JPH09211411A - Liquid crystal display method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display method and device to display in a large scale in parallel without losing resolution and being conspicuous by its boundary lines of plural liquid crystal panels. SOLUTION: Each of plural liquid crystal panel faces uses one consisting of a light source of parallel light illumination to illuminate the panel face from the back by making the parallel light or its approximate light incident on the panel face nearly vertically, a liquid crystal panel 1, and a lens array 4 of converging lenses placed on the panel face in each cell or pixel of the liquid crystal panel 1, and in front of the plural liquid crystal display panel 1, concave lenses 9 and a projection screen 5 are arranged in the order and the concave lenses 9 are arranged in a corn-shaped light flux of the transmission light formed by the converging lens by cell or pixel of the liquid crystal panel 1. Also, a length between the liquid crystal panel 1 and the projection screen 5 is made to be such one as the exit light passing through the converging lens and the concave lens 9 by cell or pixel forms a luminescent point onto the projection screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display method and a liquid crystal display device, and more particularly to a liquid crystal display device in which a plurality of liquid crystal panels are arranged in parallel to form a larger liquid crystal display device. The present invention relates to a thin large-sized liquid crystal display device in which a boundary between a plurality of liquid crystal panels is made inconspicuous by individually projecting a transmitted light flux onto a screen surface to obtain an integrated image.

[0002]

2. Description of the Related Art In a general liquid crystal display device, liquid crystal is filled between two flat substrates on which pixel electrodes are formed, and by applying a voltage between them, the alignment of liquid crystal molecules is controlled to switch light. This is a device for displaying an image. This technique is fine and precise, and it is known that it is technically and economically difficult to form a large-sized display device with a single liquid crystal panel. As a solution to this problem, a method of enlarging and projecting a small liquid crystal display device onto a projection screen surface by a lens optical system is adopted, and it has reached the stage of being commercially available.

In contrast to the magnifying projection method, recently, a method of joining a plurality of small liquid crystal panels to obtain a large-area display body has been announced. There are two types, one is a method of precisely polishing the end faces of the liquid crystal panel and joining them accurately to make one large panel while making it impossible to distinguish the joints, and the other is Multiple small panels are arranged side by side at an appropriate narrow interval, illuminated from the back of the liquid crystal panel using parallel light, and the image displayed by each liquid crystal panel is projected at equal size using a lens array in which a large number of small lenses are arranged. , It is a method of displaying it by projecting it on the screen surface with a slight magnification using a concave Fresnel lens, and by enlarging it, it is possible to adjust so that the end faces of each liquid crystal panel can exactly overlap. Has a feature that makes it inconspicuous (the former is Asia Display '9
5, processingings-p. 201: Large
Area Liquid Crystal Displ
ayRealized by Tilling of
Four Back Panels, the latter is the same pr
ocedings-p. 197: LCD Multi
-Panel Display-1995, 10, 16
~ 18 held-. ).

[0004]

The display image of a liquid crystal display device is gradually becoming higher in quality as far as it is viewed by a direct view type, and reaches the same level as that of a CRT. However, if it is a direct-view type and can be upsized, it is thin and thus has a wide range of applications such as a high-quality wall-mounted television, but as described above, it is difficult to upsize.
Therefore, the magnifying projection type was manufactured, but when magnifying and projecting with a lens system, especially in high-magnification magnifying projection, the resolution is lowered and the image quality is inevitably deteriorated. .

On the other hand, in the method of accurately attaching the end faces of the liquid crystal panel to form one large panel, since the liquid crystal display device is a direct view type, the image quality itself can be kept as high as that of a general display body. However, there is a drawback in that precise manufacturing is required for manufacturing, productivity is low, and the cost is high.

Further, in the method of juxtaposing a plurality of liquid crystal panels side by side and projecting an image with a lens array, although the image is slightly magnified, it is projected at substantially the same magnification, which is advantageous in comparison with the high magnification magnifying projection method. is there. However, the method of projecting the image formed on each unit panel with the lens array is the method of recombining the images that are projected in small divisions with the unit lenses of the lens array to display the entire image, so each lens of the lens array is displayed. Must be precisely aligned with the same focal length, which makes it difficult to manufacture. If the constituent lenses are non-uniform, the projected image by that lens will be different from the projected images of the other lenses and will disturb the entire image.

Further, in this method, as in the case of the magnifying projection method, in principle, an image forming optical system of a lens is used, so that the optical path length from the display image to the projection image depends on the focal length of the lens. Since it is theoretically determined and its optical path length cannot be changed, the device as a whole must be thick. That is, it is impossible to reduce the thickness.

As described above, the conventional ones are insufficient as thin and large-sized liquid crystal display devices which are currently most demanded and which are inexpensive and can obtain high-quality images, and are not capable of satisfying this demand. Absent.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to arrange a plurality of liquid crystal panels inconspicuously in parallel without deteriorating the resolution and to display a large display. A liquid crystal display method and a liquid crystal display device are provided.

[0010]

A liquid crystal display method of the present invention which achieves the above object is a method of arranging a plurality of liquid crystal display panels in parallel to form a larger liquid crystal display device. As a parallel light illumination light source for illuminating parallel light or its approximate light from the back surface of the liquid crystal display panel substantially perpendicularly to the panel surface, a liquid crystal panel, and a liquid crystal cell or liquid crystal pixel of the liquid crystal panel on the panel surface. A lens array composed of converging lenses arranged directly or close to each other is used, and a concave lens and a projection screen are arranged in this order on the front surface of the plurality of liquid crystal display panels arranged in parallel, and the converging lens is used to The concave lens is arranged in a cone-shaped light flux of transmitted light formed in a liquid crystal cell or a liquid crystal pixel unit of a liquid crystal panel, and the liquid crystal panel and the projection screen are arranged. The distance between the emission is a method which is characterized in that the emitted light transmitted through the convergent lens and the concave lens of each liquid crystal cell or liquid crystal pixel is the distance at which the bright spot with respect to the projection screen.

Further, the liquid crystal display device according to the present invention is a liquid crystal display device in which a plurality of liquid crystal display panels are combined in parallel, and each of the plurality of liquid crystal display panels receives parallel light or its approximate light from the back surface of the liquid crystal display panel. A collimated illumination light source that illuminates a panel surface by being incident substantially perpendicularly thereto, a liquid crystal panel, and a lens array including a converging lens arranged directly or close to the panel surface for each liquid crystal cell or liquid crystal pixel of the liquid crystal panel. The concave lens and the projection screen are arranged in this order on the front surface of the plurality of liquid crystal display panels that are composed in parallel, and the transmitted light formed by the converging lens in the liquid crystal cell or the liquid crystal pixel unit of the liquid crystal panel. The concave lens is arranged in the cone-shaped light beam, and the distance between the liquid crystal panel and the projection screen is set in front of each liquid crystal cell or liquid crystal pixel. It is characterized in that the converging lens and emitted light transmitted through the concave lens has a distance to be a bright spot with respect to the projection screen.

In this case, it is desirable that the surface of the projection screen which intersects the light flux from the liquid crystal cell or liquid crystal pixel unit is light diffusive.

It is also desirable that the projection screen be gray.

Further, it is desirable that a black boundary line is provided in a portion adjacent to the liquid crystal cell or the liquid crystal pixel projected on the projection surface of the projection screen in a range that does not obstruct the light flux.

Further, it is desirable that the converging lens existing in the unit of the liquid crystal cell or the liquid crystal pixel is configured to condense the light transmitted through the liquid crystal cell or the pixel substantially uniformly at the focal position of the lens array.

Further, the lens array may be formed in a lenticular lens shape in units of columns of liquid crystal cells or liquid crystal pixels.

Further, the concave lens can be constructed as a lens having a continuous surface or a Fresnel lens.

Further, the parallel light illumination light source is arranged such that the illumination light sources are arranged in parallel on the back surface of the liquid crystal panel or installed at the end of the light guide plate to obtain parallel light or its approximate light. Is desirable.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Among the above-mentioned conventional methods, in the method of projecting a plurality of liquid crystal panels in parallel, in principle, the optical path length of the imaging lens optical system is constant, so long as the same lens is used. , The optical path length cannot be changed. Although it is practically desirable to make the thickness of the display device as thin as possible, it is concluded from the above-mentioned literature that the minimum optical path length (the thinnest device) is practically 1: 1 projection. There is. However, since this projection method images and projects the original image on the screen surface, it is not possible to further shorten the optical path length to form a thinner device.

The present invention is based on the principle described below.
Without using the above-mentioned imaging lens system, the light from the cells or pixels of the liquid crystal panel is independently condensed, and the projection screen is placed in the condensed light flux, whereby a remarkably thin liquid crystal display is obtained. The inventors have found that a device can be manufactured, and have invented a thin liquid crystal display device based on a novel principle.

The principle of construction of the liquid crystal display device of the present invention will be described below with reference to the drawings. FIG. 1 shows a projection screen in the optical path before condensing of a luminous flux group obtained by providing a condenser lens for each R, G, B cell of the liquid crystal panel in the method of utilizing the condensed luminous flux of the present invention. It is the optical-path figure arrange | positioned. R, G,
Transmission illumination is performed from the back surface of the liquid crystal panel 1 in which the B cells 2 are regularly arranged by using parallel light 3. In the case of FIG. 1, the parallel light 3 corresponds to the LCD Multi-Panel D described above.
As described in “isplay”, it is obtained by using the fluorescent tubes 6 arranged in parallel and the light guide tube sheet 7 having a transparent cone-shaped light guide section. 3 formed in the liquid crystal panel 1
The primary color cells 2, that is, the red cells (R), the green cells (G), and the blue cells (B) are formed by providing any of the three primary color filters corresponding to each cell. Therefore, each color cell R, G, B includes all general cell components. In order to display a color image on the liquid crystal panel 1, a change in the orientation of liquid crystal molecules when a voltage is applied to each cell 2 is used, and a polarizing plate (may not be used) arranged on both sides of the liquid crystal layer is used. It is well known that the function of transmitting or blocking the parallel illumination light 3 is electrically controlled by the light switching function by the cooperative action.

The parallel illumination light 3 passes through each of the primary color cells 2 which are the constituent elements of the liquid crystal panel 1 and becomes a corresponding color light. For example, the transmitted light of the red cell (R) becomes red light. If the parallel transmitted light is not disturbed, the transmitted light of each primary color cell 2 does not disturb the arrangement of the R, G, B cells of the liquid crystal panel 1, so that the R, G in the exactly same arrangement and in a clearly separated state. , B light flux is emitted outside the panel 1.

When the projection screen 5 is placed parallel to the liquid crystal panel 1 at a position where the light flux is blocked, the light flux is projected as a bright spot on the screen 5 surface, and a bright light flux projection image can be seen from the opposite side of the projection surface. it can. In this case, if perfectly parallel light is transmitted, theoretically, even if the distance between the screen 5 and the liquid crystal panel 1 (screen distance) is an arbitrary position, the same projected image as the liquid crystal panel 1 is always obtained. Will be obtained.

However, in reality, perfect parallel light illumination is impossible, and since the liquid crystal panel 1 also has a slight light diffusing property, the transmitted light flux is disturbed and the adjacent cells are affected to add and mix lights. And the cell boundaries of each other become unclear.
Here, if the distance from the liquid crystal panel 1 to the projection screen 5 is large, the cell boundaries are disturbed due to the disturbance of the light flux, and the cell array of the liquid crystal panel 1 cannot be reproduced. for that reason,
Even if the liquid crystal panel 1 is electrically switched, the resolution is deteriorated on the projection surface of the screen 5, and the action may not be apparent. In this state, the image displayed on the liquid crystal panel 1 can no longer be reproduced, the projected image becomes unclear, and the image cannot be put to practical use.

Therefore, according to the present invention, the converging lens group 4 is arranged such that one converging lens is positioned on the exit surface of each primary color cell 2, and the characteristics of each converging lens are collimated to make the exit light parallel light again. The above problem can be easily solved by using a lens or condensing light at a specific focal point by positive refracting power.

In FIG. 1, as a method that is easier to manufacture than to obtain parallel light, a convex lens is arranged on each of the two surfaces of the R, G, and B cells, and each lens is focused at a focal point P at the same distance. The projection screen 5 is arranged in parallel with the liquid crystal panel 1 at an appropriate position in the condensing cone.

Since the screen 5 traverses and scatters the light flux, a bright image of the projected area of the light flux can be obtained for each cell. Since the light flux has a conical cone shape, the light does not reach between the adjacent cells and thus becomes a dark portion, so that the boundary between the bright images is clearly separated. This state means that when each of the constituent cells 2 of the liquid crystal panel 1 is optically switched, the effect can be completely reproduced on the screen 5 surface. That is, the image displayed on the liquid crystal panel 1 is 1: 1.
It means that it can be reproduced on the surface of the projection screen 5 with the size of. Even if the position of the screen 5 is closer to the liquid crystal panel 1 (screen-3) or further away (screen-1), the bright projection area of the light flux formed on the surface of the screen 5 changes, but The cell boundaries are clearly distinguished and the display effect is exactly the same.

As can be seen from FIG. 1, the area of the light flux of each cell 2 brightly projected on the screen surface varies depending on the position of the screen 5 in the light flux cone. The closer the position of the screen 5 is to the lens focal point P, the smaller the area of each light beam, and the closer it is to the liquid crystal panel 1, the larger the area of the individual light beams.
Approach the area of. On the other hand, it is natural that the light intensity is condensed and becomes stronger as the projection area is smaller, and becomes weaker as the projection area is larger. However, the light intensity of cell 2 (light intensity x area)
Can be said to be the same whether the position of the screen 5 is (screen-1), (screen-2) or (screen-3). This means that the brightness of the display image does not change depending on the position of the screen 5 (size of the projected bright spot) in a general macroscopic observation of visually observing the projection screen 5.

Further, since the display is performed by synthesizing two cells, the projected image with the cells clearly separated on the screen 5 surface is exactly the same as the original image displayed on the liquid crystal panel 1. I can say. That is, although the image of the conventional image projection method is always accompanied by the deterioration of the resolution, the present invention has a great feature that the resolution is the same as that of the original image. Therefore, by using the light beam projection method of the present invention, the distance between the liquid crystal panel 1 and the projection screen 5 can be reduced, and a thin liquid crystal display device can be manufactured in which the obtained projected image does not deteriorate the resolution of the original display image. .

In FIG. 1, when the projection screen 5 is located outside the focal point P, since the light beam has an inverted conical shape, the light beam cross-sectional area gradually increases as the screen moves away, but the boundary between adjacent cells is clear. As long as
It is the same as the above effect. However, when the neighboring cells become large enough to overlap, the above effect is gradually reduced. Since it is practically difficult to adjust such a position, it is easier to install the projection screen 5 within the focus P.

In the lens group 4 in which the converging lenses are arranged in cell units, the display panel can be arranged in any arrangement such as a parallel linear stripe arrangement of R, G, B cells, or a staggered arrangement or a delta arrangement. it can.

The lens group 4 arranged in the cell unit of FIG. 1 may be arranged in the pixel 22 unit composed of a set of adjacent R, G and B as shown in FIG.
Since the lens-transmitted light is also cone-shaped, if the screen 5 is placed in the cone, the adjacent pixels 22 are clearly distinguished as described above. Further, the cone-shaped light flux is R,
When all G and B cells are transmitted, naturally R,
Since G and B three primary colors are included, white is produced by the additive mixing of light. If the cell B is shielded, R + G is emitted and yellow light is emitted. If the cell G is shielded, magenta light is emitted. If the cells G and B are shielded, red light is emitted, and thus a multicolor coloring function is exerted within the light flux of one pixel 22.

In FIG. 1, since it is a unit of 2 cells, it is not preferable to overlap adjacent cells. However, in FIG. 2, since it is a unit of 22 pixels, even if there is mixing of colored light due to cell overlapping within that unit, Since the principle of display is that an image line or a color image is originally formed in units of pixels 22, no problem occurs. The primary color (primary color), the secondary color (mixture of two colors), and the tertiary color (mixture of three colors) obtained by the color light selected in the RGB unit are the primary colors of other RGB unit pixels 22, The target color image can be obtained as a whole by properly combining the secondary color and the tertiary color. Regarding the resolution, since the image configuration is performed in units of pixels 22, it can be reproduced in the same manner as the original image as long as the projected pixel does not change. Therefore, as shown in FIG.
And a light beam cone for each pixel 22 is used, the same effect as that of the above cell unit method can be obtained.

In the case of FIG. 2, the individual lens for each pixel 22 is naturally larger than in the case of FIG. 1, so that there is an advantage that the lens group 44 can be easily designed and manufactured. The effect is theoretically the same as the case where the individual lenses are arranged in the cell 2 unit of FIG.

If the R, G, B cells 2 or pixels 22 are arranged in a stripe pattern, one rod-shaped lens group (lenticular lens or kamaboko lens) can be used instead of the lens group for each cell 2 or pixel 22. . In this case, the boundary between the cell 2 or the pixel 22 in the direction parallel to the lenticular lens becomes unclear, which causes some resolution and deterioration in image quality, but it is practically acceptable, and in the production of the lens group. On the other hand, it has the advantage of being extremely easy and inexpensive.

Next, the basic structure of the large-sized liquid crystal display device of the present invention in which a plurality of display panels having the above-mentioned configuration as shown in FIG. 1 or 2 are arranged in parallel will be described. The basic required specifications of a large-sized liquid crystal display device are that it is thin, and that joints of a plurality of display panels in a parallel arrangement do not interfere with image observation. The structure in which this joint cannot be recognized is most desirable.

As described above, conventionally, the panels are arranged in parallel at appropriate intervals, a lens system is provided on each panel to enlarge the panel (display image), and only the display image of the adjacent panel is displayed on the screen surface. There is a method of making the seams inconspicuous by splicing them together and erasing the space between the panels (see L
CD Multi-Panel Display). The panel expansion ratio in this case is reported to be 1.2 times.

When the screen is arranged in the condensed light flux of the lens group 4 of the present invention described above, if the scattered light of the light source 6 is made into the parallel light 3 by using the light guide sheet 7, for example,
Since the projected bright spots accurately reproduce the pitch of the cells 2 or the pixels 22 of the original panel 1 and become a 1: 1 projection as shown in FIG. 1, as long as the screen and the liquid crystal panel are arranged in parallel,
Adjacent panel spacing is saved and panel images cannot be stitched together.

Therefore, as shown in FIG. 3, a plurality of liquid crystal panels L ₁ (1), L ₂ (1), ... L _n (1) are arranged in parallel and arranged in parallel with the projection screen 5, and the screen 5 If the projected images of the planes can be enlarged and the edges of the display images from the respective panels L ₁ , L ₂ , ... L _n can be overlapped with each other, the adjacent panels L ₁ , which are arranged at a slight distance, L
The effective display image edges of ₂ , ... L _n can be brought into contact with each other accurately (in FIG. 3, each lens of the lens group 4 is represented by a simple rectangle for simplicity).

The enlargement ratio for effective display image edge of the panel L _1, L ₂ of the adjacent overlap on the screen 5 side is adjacent panels L _1, L _2, of the effective display image edge of · · · L _n It is determined by the distance and the distance between the screen 5 and the image end thereof, and as a means for enlarging, a concave lens 9 may be arranged between the minute lens groups 4 and 44 and the screen 5 as shown in FIG. The concave lens 9 refracts the light beam cone that has passed through the lens group 4 in the outer peripheral direction, and the focal points P1 ′, P2 ′ ...
Are farther than the focal points P1, P2 ... Therefore, the pitch of the bright spots on the screen 5 becomes larger than the pitch of the original cells 2 or the pixels 22, and the entire image of the projected display image is enlarged.

Here, it is desirable that the concave lens 9 has a quadrangular outer periphery in accordance with the size of the liquid crystal panel 1. The reason for this is that the smaller the distance between the adjacent panels is, the smaller the enlargement ratio is and the smaller the curvature of the concave lens 9 is. Therefore, the processing is easy and the thickness can be reduced. To make a thinner plate-shaped or sheet-shaped lens, a Fresnel lens that is a concave lens can be used, as is well known.

By the way, if the enlarging effect of the concave lens 9 is too large, the light flux becomes diffused, and the projected cells 2 or pixels 22 cross the boundary between them. In this case, the projected individual cells or pixels are overlapped with each other, so that the resolution is lowered and the color reproduction of the color image is deteriorated, which is not preferable. Therefore, the magnifying effect must be limited to the range where the projected cells or pixels on the screen 5 are clearly distinguished.

Based on the above theory, in the plurality of parallel liquid crystal panels 1 illuminated by the parallel light 3, the combination of the lens groups 4 and 44 and the concave lens 9 causes the luminous points of the luminous flux to be projected on the surface of the screen 5 as an enlarged image type. It was shown that it is possible to obtain a joined image in which the joint between adjacent images becomes inconspicuous when visually observed.

Next, members that can be used in the large-sized liquid crystal display device of the present invention will be described. With respect to the projection screen 5, it is necessary to project a light beam and make it shine on the screen surface, and therefore the projection surface 8 must be light-scattering. Generally, it is best to use a semitransparent cloth or paper, or a commercially available transparent glass or plastic plate (made of acrylic resin, polyester resin, vinyl chloride resin, or other resin) with a white pigment applied on one surface. Cheap but transparent glass or plastic plate or sheet with one surface roughened (mechanically roughened product, chemically roughened product, etc.), fine powder with different light refractive index on the transparent plate surface Applied with a binder,
Alternatively, fine glass beads coated in the same manner can be used. The light-scattering surface may be on the inside or outside of the screen, but it is not necessary to consider the refraction of the light flux, interface reflection, etc. if it is formed on the inner side, and mechanical abrasion due to external force etc. can be protected. Therefore, it is more preferable.

To increase the image contrast on the projection surface,
A slightly gray screen is more visually suitable than a pure white screen, and it is effective to color the screen to a gray level of 0.2 to 0.5. Further, more preferably, if a black boundary (black matrix) is formed on the projection surface 8 of the screen 5 in units of cells or pixels and the projection light beam is aligned so as to be projected within the black boundary line, the whole is obtained. Since the effect of the above gray coloring and the stray light that may be generated due to various causes are absorbed and blocked, a display image with better image quality can be obtained.

Next, a lens (convex lens) group (lens array) that collects transmitted light is required for each cell or pixel of the liquid crystal panel 1. There are several methods for producing the lens groups 4 and 44. is there. For example, one of them is a method of producing a lens press mold having a curvature of a focal length defined by a required size and press-molding a plastic sheet, or a method of injection-molding a lens sheet,
Apply a transparent curable resin such as photocurable or thermosetting resin to the liquid crystal panel surface (generally the glass surface), align the lens press mold with the cell or pixel array accurately, and apply light or heat. It is a method of peeling the template after curing.

The former method can obtain a lens sheet which can be mass-produced and is inexpensive, but in general, heat is applied, so that the dimensional change of the lens sheet at room temperature occurs due to the thermal expansion coefficient of the press die. It is necessary to adjust the press conditions etc. accurately. Also, the lens sheet must be accurately aligned and fixed to the panel side.

On the other hand, the latter is advantageous in that it can be cured even at room temperature, especially when a photocurable resin is used, and if the initial alignment is accurate, there is almost no error even if the mold is peeled and removed. When the template is made of an opaque material such as metal, light can be applied from the panel side, and when it is made of a transparent material such as glass,
It can be photocured through it (known as the 2P method). However, mass productivity is inferior to the former method. In the photo-curing method, many acrylic photosensitive resins and other suitable resins are already on the market, and they can be selectively used.

As another known method for manufacturing the lens groups 4 and 44, there are known methods such as an optical hologram lens forming method and an impurity diffusion method (ion doping etc.).

The hologram lens is made of a photosensitive material for hologram (silver salt emulsion, photosensitive resin, etc.) in which laser beams are interfered with each other to produce a hologram having a lens effect. There is a method of drawing a line and utilizing the diffraction effect.

The impurity diffusion method utilizes the fact that, for example, alkali ions such as Na ions of a soda glass component are replaced with other metal ions and the like, and a difference in refractive index occurs depending on the ion replacement density. As an example, after forming a pinhole mask such as a metal thin film on the surface of the substrate, when performing ion doping or molten salt immersion from this pinhole, the diffusion substitution region spreads out in a hemispherical shape around the pinhole, and, Concentration differences in doping and diffusion displacement material are continuously formed in the substrate. Therefore, the highest concentration is in the vicinity of the pinhole, and the lower the concentration is, the lower the concentration becomes. This difference in concentration continuously changes the refractive index of the substrate, so that the transmitted light is refracted. The principle that a lens effect can be obtained by using this is used (for example, Society for I
nformation Display (SID) '9
2 Digest. 269). This effect can be obtained not only by using glass but also by doping a specific polymer film coated on a transparent substrate with another ion atom.

Since both the hologram lens and the ion-doping lens utilize diffraction or refraction of light, the region for obtaining the lens effect is formed in the material thereof, and thus constitutes a plane lens group. Further, since optical processing or photolithography technology can be used, there is an advantage that the formation and arrangement of the minute lens groups can be performed with extremely high accuracy.

When the projected image on the screen 5 is viewed, the quality of the image quality is determined by the psychological influence which cannot be discussed only by the physical quantity of light. In the subject etc., if necessary,
It is also possible to design and process by continuously changing the curvatures of the lens groups 4 and 44 so that they differ between the central part and the peripheral part.

The light beam cone obtained by the minute lens groups 4 and 44 can only be projected at the same size as described above.
The concave lens 9 for refracting the light flux and enlarging and projecting it is necessary. Since the characteristic unevenness of the concave lens 9 is reproduced as the unevenness of the projected image or the distortion of the screen, its quality is important.
Generally, a polished glass lens commercially available as an optical lens is preferable. In order to reduce the cost, a transparent plastic lens using an acrylic resin or the like can be used if appropriately selected. The curvature of the concave lens 9 is determined by the distance from the concave lens 9 to the screen 5 and the enlargement ratio.

If importance is attached to the thinness of the display device, a sheet type Fresnel lens can be used as the concave lens 9, and it is preferable to use a glass or transparent plastic Fresnel lens as the material.

Regarding the device or member for obtaining the parallel light 3 for illuminating the liquid crystal panel 1, the LCD Multi described above is used.
-A method for obtaining parallel light described in the Panel Display by utilizing parallel arrangement of fluorescent tubes 6 and multiple reflection of a light guide tube 7 structure having a transparent cone-shaped light guide section can be used. A method for improving the parallelism of collimated light can be performed within the technical range.

Further, an edge light type backlight in which a thin fluorescent tube used in a general small liquid crystal display is attached to an end of a glass plate or an acrylic plate is also processed in a prism shape for efficient use of light. And the addition of a microlens group has been devised, and it has become possible to obtain output light of considerably high quality as parallel light, and it is possible to selectively use them.

As described above, since the technology and members for manufacturing the large-sized liquid crystal display device of the present invention have been established, the intended large-sized liquid crystal display device can be easily manufactured by using the basic principle of the present invention. it can.

In the present invention described above, a plurality of liquid crystal panels are arranged in parallel to perform a large-scale display of approximately 1: 1. However, a luminous flux of transmitted light is formed in liquid crystal cells or liquid crystal pixels. Since the principle is that the projected image of the light flux is projected and arrayed on the projection screen surface, there is basically no reduction in resolution, and a display image with substantially the same image quality as a direct-view type liquid crystal display device can be obtained. In addition, since the image forming lens system is not used, the influence of distortion such as lens distortion can be minimized. Therefore, minimizing the change in the straight line at the edge of the adjacent panel image,
It is possible to make the joints of each other precise and inconspicuous.

Further, the use of the transmitted light flux of the liquid crystal cell or the liquid crystal pixel unit has an advantage that the optical path length can be remarkably shortened as compared with the method of using the image projection optical system, and the thickness of the large display device ( The depth can be reduced to make a thin device.

Further, the processing and manufacturing for obtaining the luminous flux of the liquid crystal cell or the liquid crystal pixel unit is generally carried out for each individual liquid crystal panel, and the completed panels are mechanically and accurately fixed in parallel. Since the device is completed, it is extremely easy to increase the size.

Further, since a comparatively small display panel is used, the manufacturing yield of the panel itself is high and the cost is low. Since it is used, a large display device can be manufactured at a low cost in accordance with the display panel used. . Further, depending on the design of each liquid crystal panel, it is possible to use both the individual display device and the large display device, which is extremely advantageous in production.

[0063]

EXAMPLES Examples 1 to 3 of the liquid crystal display device of the present invention will be described below.
Will be explained in detail. [Example 1] The effective display area is 210 mm x 160 mm,
Two glass liquid crystal panels for transmitted light color display having a frame portion (non-display portion) of 4 mm were used to fabricate a liquid crystal display device having a size twice (210 mm × 320 mm) with their long sides being adjacent to each other.

First, as a projection screen, a commercially available self-colored paint was diluted with a little toluene on one surface of a transparent glass plate, uniformly spin-coated and dried to form a semi-transparent film having a thickness of 2 μm. Was used.

The liquid crystal panel had the above size, the cell pitch was 110 μm × 330 μm, and the color filter used was a stripe type in which R, G, and B were sequentially arranged in strips. There is no restriction on the liquid crystal driving method, but the TFT method is used.

In order to form a microlens group on a liquid crystal panel in cell units, a metal press die that can obtain a spherical lens group designed to have a focal length of 80 mm has a linear expansion coefficient similar to that of a glass substrate. Invar material (main component: Fe, Ni, etc.) was cut and produced, and the surface thereof was smoothly polished.

Then, a transparent thermosetting acrylic resin is applied to the uneven surface of the press die, and while accurately aligning the cell position of the liquid crystal panel and the lens position of the press die with an aligner, the glass surface of the panel is After that, the mixture was left to stand at 90 ° C. overnight for curing, and after cooling, the panel and the press mold were peeled off. By this operation, an acrylic resin microlens group having a focal length of 80 mm could be formed on the glass surface of the panel.

Next, a concave lens having substantially the same size as the liquid crystal panel was placed in parallel on this lens group. The concave lens was made of glass, and the distance from the liquid crystal panel was 5 mm.

Next, using the microlens group and the liquid crystal panel with a concave lens, a jig was prepared which could fix the above semitransparent glass screen and the liquid crystal panel in parallel, first fixed the screen thereto, and then shown in FIG. As described above, the panel surface was separated from the scattering surface of the screen by 50 mm, and the adjacent sides of the effective image areas of the two panels were set to 10 mm and arranged in parallel. That is, a liquid crystal panel, a minute lens, a concave lens,
An apparatus having a configuration in which the projection screen is arranged in this order is obtained.

In this embodiment, as a light source for transmitted illumination, a single light source of a 200 W metal halide lamp (manufactured by Iwasaki Electric Co., Ltd.) was used in order to experimentally obtain near-ideal parallel light. A black light-shielding plate with a 2 mm pinhole opened 100 mm from the light source with a distance of about 1 m was used, and the output light from the pinhole was regarded as a point light source, near the panel rear face of the above assembled liquid crystal display device. A large glass convex lens for collimation was installed to obtain parallel light.

Even if the illumination light source is strong, the light utilization efficiency by the light shielding plate and the collimating lens was not so good,
Good quality parallel light was obtained. This parallel light was used to irradiate from the back surface of the liquid crystal display device assembled in this example.

The entire area of the two liquid crystal panel images was projected on the screen surface, but slight overlap was observed at the edges of the adjacent images, so adjustment was made by hand to obtain good adjacent images. . As a result, although the light utilization efficiency was poor and the display image was slightly dark, a good composite image was obtained in which the joined portion of the two images was visually inconspicuous.

When the projected image was observed with a microscope, each pixel was clearly separated, and therefore no reduction in resolution was observed.

[Embodiment 2] A liquid crystal panel (so-called 10-inch panel) used in Embodiment 1 is used, and a 20-inch display is formed in a square-shaped array (2 × 2 array in vertical and horizontal alignment). Was prepared. The projection screen also has a size of 2
The same glass plate as in Example 1 having a semitransparent film was used only for 0-inch display.

For the production of the minute lens group, a method of producing a flat lens sheet is used which obtains a lens effect by utilizing a refractive index change by an impurity diffusion method (or an ion substitution method). However, in this embodiment, since the process is performed in pixel units (including 3 cells of R, G, and B in each unit) instead of cell units, the size of one lens is a pixel size of 330 μm ×
Same as 330 μm.

Specifically, N of the same size as the liquid crystal panel is used.
Glass substrate containing alkali ions such as a (thickness 1 mm)
Using Ti, a thin film of Ti metal is vapor-deposited on the surface thereof, and then a window for ion exchange is formed by etching at a pixel pitch by a photolithography method, and the residual Ti film is used as a mask.
A molten salt of thallium nitrate was used for immersion in the molten salt to replace the alkali ions with the thallium ions.

The refractive index changes due to this ion substitution, and since hemispherical diffusion is replaced from the mask opening, a lens effect is exhibited. However, since the pixels are arranged in a mesh, there is a portion where ion substitution is not performed even if the closest packing is attempted. Since this portion does not have a lens effect and thus does not have a light-collecting effect and adversely affects pixel separation, Ti of the mask is circularly etched and removed again by the photolithography method and left as a mask for unnecessary light.

Further, since the difference in refractive index becomes larger in the portion where the number of ion substitutions is large, and the general lens is a short focus lens, the desired long focus lens cannot be obtained. Therefore, it has been necessary to experimentally select the glass material, the substitution conditions, and the like so that a good ion substitution density can be obtained.

In some cases, the focal length does not reach the target distance. In this case, a curable transparent acrylic resin having a refractive index of about 1.5 (a slightly lower refractive index than glass) is applied to the lens surface. The coating was applied to a uniform thickness of about 30 μm to extend the focal length and achieve the purpose.

Since this diffusing lens group is one glass plate, it was fixed to each other by aligning it with the pixels of the liquid crystal panel.

Then, similarly to the previous example, a concave lens cut into the same size as the panel substrate is adhered onto the minute diffusing lens plate to bend the condensed light beam in the outer peripheral direction to have an expanding effect. The four panels were arranged side by side in a square shape at 10 mm intervals and were fixed together with the projection screen at a distance of 50 mm from the panels. Next, a common parallel light source was installed on the back surface of the four panels.

In the parallel light source of this example, tubular fluorescent lamps (40 W) are used as light sources arranged in parallel at intervals of 50 mm, and a light guide plate is provided at a position 50 mm from the fluorescent lamps in parallel with the fluorescent lamp array to scatter. The light was adjusted in parallel, and the distance between the light guide plate and the panel was set to about 10 mm.

This light guide plate is made of an aramid resin plate having a thickness of about 20 mm, which has a thermal expansion and contraction property similar to that of glass, and 1 mm holes are formed by laser processing at the same pitch as the pixel pitch. The entire surface including the rear opening is electrolessly plated with Ag by a silver mirror reaction so as to serve as a light shielding film and a multiple reflection film.

In this apparatus, the projected image was observed from the screen side, and although the seams were slightly adjusted, it was possible to observe a good composite image in which the image joining portion was not so conspicuous.

[Embodiment 3] In Embodiments 1 and 2, the solid content is 2 in the material for forming the semitransparent light scattering film of the projection screen.
% Carbon black powder was mixed and used by being gray-colored with a reflection density of 0.5, the apparent contrast was improved as compared with Examples 1 and 2, and the display image was easier to see.

Also, instead of coloring in gray, the second embodiment is used.
In, a black matrix having a line width of 50 μm was formed according to the calculated value of the projection pixel pitch, and the projection pixels were aligned and observed. As a result, the contrast was improved, and it was easier to see and a sharp display image was obtained. .

Although the liquid crystal display method and the liquid crystal display device of the present invention have been described above based on the explanation of the principle and some embodiments, the present invention is not limited to these and various modifications can be made. .

[0088]

As is clear from the above description, according to the liquid crystal display device of the present invention, basically no deterioration in resolution occurs, and a display image having substantially the same image quality as that of the direct-view type liquid crystal display device is obtained. can get. In addition, it is possible to minimize the change in the straight line of the edge portion of the adjacent panel image, and to make the mutual joining precise and inconspicuous. In addition, it is extremely easy to increase the size, and the thickness (depth) of the large display device can be reduced to form a thin device. Further, there is an advantage that it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is an optical path diagram showing a configuration of an example of a liquid crystal display panel which is a premise of the present invention.

FIG. 2 is an optical path diagram showing the configuration of another example of the liquid crystal display panel which is the premise of the present invention.

FIG. 3 is a diagram for explaining a configuration when a plurality of liquid crystal display panels are arranged in parallel according to the present invention.

FIG. 4 is an optical path diagram showing a configuration of an example of each liquid crystal display panel arranged in parallel according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal panel 2 ... Cell 3 ... Parallel light 4 ... Convergence lens group 5 ... Projection screen 6 ... Fluorescent tube 7 ... Light guide tube sheet 8 ... Projection surface 9 ... Concave lens 22 ... Pixel 44 ... Convergence lens group L ₁ , L ₂ ... LCD panel

Claims (9)

[Claims] 1. A method of arranging a plurality of liquid crystal display panels in parallel to form a larger liquid crystal display device, wherein parallel light or its approximate light is emitted from the back surface of the liquid crystal display panel as a plurality of liquid crystal display panels. And a liquid crystal panel, and a lens array composed of converging lenses arranged directly or close to the panel surface for each liquid crystal cell or liquid crystal pixel of the liquid crystal panel. Using a thing, in the front of the plurality of liquid crystal display panels arranged in parallel, a concave lens, a projection screen are arranged in this order,
The concave lens is arranged in a cone-shaped light flux of transmitted light formed in a liquid crystal cell or a liquid crystal pixel unit of the liquid crystal panel by the converging lens, and a distance between the liquid crystal panel and the projection screen is set to a liquid crystal cell or a liquid crystal. A liquid crystal display method, wherein a distance at which the emitted light transmitted through the converging lens and the concave lens for each pixel becomes a bright spot with respect to the projection screen. 2. A liquid crystal display device comprising a plurality of liquid crystal display panels combined in parallel, wherein parallel light or its approximate light is made to enter the panel surfaces substantially vertically from the back surface of the liquid crystal display panels. Parallel light source for illuminating with a parallel light source, a liquid crystal panel, and a lens array composed of converging lenses arranged directly or close to the panel surface for each liquid crystal cell or liquid crystal pixel of the liquid crystal panel, and the parallel composition The concave lens,
Arranged in the order of the projection screen, the concave lens is arranged in a cone-shaped light flux of transmitted light formed by the converging lens in a liquid crystal cell or liquid crystal pixel unit of the liquid crystal panel, and the liquid crystal panel and the projection screen. The liquid crystal display device is characterized in that the light emitted from the converging lens and the concave lens of each liquid crystal cell or liquid crystal pixel becomes a bright spot with respect to the projection screen. 3. The liquid crystal display device according to claim 2, wherein the projection screen has a light-diffusing surface that crosses a light flux from a liquid crystal cell or a liquid crystal pixel unit. 4. The liquid crystal display device according to claim 2, wherein the projection screen has a gray color. 5. A black boundary line is provided in an area adjacent to a liquid crystal cell or a liquid crystal pixel projected on the projection surface of the projection screen within a range that does not obstruct the light flux.
5. The liquid crystal display device according to any one of items 4 to 4. 6. The converging lens existing in a liquid crystal cell or liquid crystal pixel unit is configured to focus light transmitted through the liquid crystal cell or pixel substantially uniformly at a focal position of the lens array. The liquid crystal display device according to any one of claims 2 to 5. 7. The liquid crystal display device according to claim 2, wherein the lens array is formed in a lenticular lens shape in units of columns of liquid crystal cells or liquid crystal pixels. 8. The concave lens is composed of a lens having a continuous surface or a Fresnel lens.
8. The liquid crystal display device according to any one of items 1 to 7. 9. The parallel light illuminating light source is configured such that the illuminating light source is arranged in parallel on the back surface of the liquid crystal panel or is installed at an end of a light guide plate to obtain parallel light or its approximate light. Any one of claims 2 to 8 characterized in that
The liquid crystal display device according to the item.