KR20000009532A - Wide visual field angle device for non-luminescent display - Google Patents

Abstract

PURPOSE: A wide visual field angle device for non-luminescent display is provided to enhance a visual field angle and optic efficiency. CONSTITUTION: The present invention discloses a wide visual field angle device for non-luminescent display comprising: a transparent substrate(16) which light output from a non-luminescent display is incident to; and a light refraction unit fixed on said substrate by transparent adhesive(10) having similar refractive index to that of said substrate and having plural parallel transparent rods(11) for outputting said output light(19) of said non-luminescent display incident through said substrate in state refracted by great angle. Said transparent rod is a transparent optic fiber.

Description

Wide viewing angle device for non-luminescent display

The present invention relates to a wide viewing angle device for a display, and more particularly, to a wide viewing angle device for a non-luminous display that can increase the viewing angle and light output efficiency of the non-luminous display.

In addition to cathode ray tubes, plasma displays, electroluminescent displays, and field emission displays all have phosphors, which operate on the principle of displaying information by emitting visible light. The display in which the self phosphor emits light is called an emissive display or a self emissive display. Luminescent displays have a wide range of viewing angles, ie viewing angles, because the phosphor emits light uniformly in all directions.

On the other hand, a non-luminescent display having no phosphor displays information by adjusting light of a light source without a phosphor. Since light emitted from the light source to the outside of the screen is directionally output, the viewing angle may be narrowed. If the viewing angle is narrow, screen brightness, color contrast, etc. vary depending on the position of the observer, and a problem arises in that it is difficult for many people to obtain accurate information on one display. Therefore, there is a need for a method for widening the viewing angle of a non-luminous display.

Liquid crystal displays representing non-luminescent displays electrically control the molecular arrangement of the liquid crystal to determine the transmission and blocking of light. The path through which light travels inside the liquid crystal display is a light source, a polarizing plate, a liquid crystal, and a polarizing plate, and the viewing angle becomes narrow due to the influence of the liquid crystal. Currently, the narrow viewing angle problem is pointed out as the biggest disadvantage of the liquid crystal display, and the following techniques have been proposed as a way to solve this problem.

The film compensation method adds a retardation film on the liquid crystal layer to compensate for the refractive anisotropy of the liquid crystal layer. This method is simple in principle but has a disadvantage of being expensive.

In-plane switching (IPS) method forms an electric field in the horizontal direction inside the liquid crystal cell so that the arrangement of the liquid crystals is changed in the horizontal direction. However, the viewing angle can be widened, but the aperture ratio is low.

VA (Vertical Alignment) method is a method to align the liquid crystal from the initial to the vertical direction to reduce the change in color or brightness according to the angle of the observer. There is difficulty.

The multi-domain method divides the alignment direction of the liquid crystal into one pixel so that light is output at various angles, and the process is complicated.

The method of using the scattering layer or the diffusing layer is a method of attaching the scattering layer on the upper polarizer to spread the final output light at various angles. This method has a disadvantage in that the light loss is large.

Although the above methods are applied to liquid crystal displays, most of them have a disadvantage in that the process is very difficult and the manufacturing cost is high because the structure of the liquid crystal must be physically adjusted.

In the case of an optical waveguide display, which is another type of non-luminescent display, the viewing angle may be narrowed because the light output from the light source is directional. In order to compensate for this, a method of inserting a scattering layer or a diffusion layer has been proposed, but as described above, there is a problem in that the light loss is large.

The technical problem to be achieved by the present invention is to provide a wide viewing angle device for a non-luminous display that can increase the viewing angle and light output efficiency of the non-luminous display.

1A is a view illustrating a wide viewing angle device for a non-luminescent display according to an embodiment of the present invention.

1B is a view illustrating a wide viewing angle device for a non-light emitting display according to another embodiment of the present invention.

FIG. 2A is a diagram illustrating a refraction phenomenon that occurs when a light beam is incident on another curved surface, and FIG. 2B is a diagram illustrating a refraction phenomenon that occurs when the light beam passes through a medium having a circular cross section.

3 is a view showing a liquid crystal display with a wide viewing angle device according to the present invention.

4A is a diagram illustrating a phenomenon that occurs when the incident angle of light is small on the transparent rod surface, and FIG. 4B is a diagram illustrating a phenomenon that occurs when the incident angle of light is large.

FIG. 5A is a view illustrating a reflection phenomenon appearing at the edge of the transparent rod, and FIG. 5B is a view illustrating a wide viewing angle device according to the present invention in which an opaque material is applied to prevent reflection.

6A is a cross-sectional view of a typical optical waveguide display, and FIG. 6B is an enlarged view of a portion A. FIG.

7A is a view showing an optical waveguide display with a wide viewing angle device according to the present invention, and FIG. 7B is an enlarged view of a portion B. FIG.

FIG. 8A is a view for explaining a wide viewing angle device for a non-light emitting display according to another embodiment of the present invention, and FIG. 8B is a front view of FIG. 8A.

<Description of the symbols for the main parts of the drawings>

10 ... transparent glue, 11 ... transparent rod,

14 ... focus, 16 ... substrate.

In order to achieve the above object, a non-light-emitting display wide viewing angle device according to the present invention includes a substrate of transparent material on which light output from a non-luminescent display is incident; And a plurality of parallel arranged transparent rods fixed on the substrate by a transparent adhesive having a refractive index similar to the refractive index of the substrate to refractively output the output light of the non-luminescent display incident through the substrate at a large angle. It includes a light refracting portion provided.

The transparent rod is preferably an optical fiber of a transparent material.

The non-luminescent display wide viewing angle device may be coupled to the light refraction portion by a transparent adhesive having a refractive index similar to the refractive index of the substrate to protect the light output from the light refraction portion to the outside. It is preferable to further include.

Further, a film of opaque material is further formed between the transparent rods in the direction in which the light output from the non-luminescent display is incident to prevent the light reflected from the surfaces of the plurality of transparent rods from entering the edges of the adjacent transparent rods. It is preferable that it is done.

In addition, the optical refraction unit has a plurality of transparent rods of two layers having a structure superimposed so as to be orthogonal to each other so as to obtain a wide viewing angle in the four directions up, down, left, and right, the surface of the plurality of transparent rods between the plurality of transparent rods It is preferable that a film made of an opaque material is further formed to block light reflected from the incident light from the edges of the adjacent transparent rods.

Hereinafter, a wide viewing angle device for a non-light emitting display according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1A is a view illustrating a wide viewing angle device for a non-luminescent display according to an embodiment of the present invention. A wide viewing angle device for a non-luminous display according to an embodiment of the present invention shown in FIG. 1A includes a substrate 16 and a substrate of transparent material on which visible rays 19 output from a non-luminous display (not shown) are incident. Refractive output of the output light 19 of the non-luminescent display, which is fixed on the substrate 16 by the transparent adhesive 10 having the same refractive index as the refractive index n1 of 16 and is incident through the substrate 16, at a large angle In order to achieve this, it is provided with a plurality of transparent rods 11 arranged in parallel to serve as a light refracting portion. Here, the transparent adhesive 10 does not necessarily have the same refractive index as the substrate 16, and may have a similar refractive index, and it is preferable to use a transparent optical fiber as the transparent rod 11.

An operation of the non-light-emitting display wide viewing angle device according to the embodiment of the present invention configured as described above will be described with reference to FIG. 1A.

In the wide viewing angle device for a non-luminous display according to an embodiment of the present invention, the visible light 19 output from the non-luminous display (not shown) is widened by being refracted at different angles by the plurality of transparent rods 11. You will have a viewing angle.

N1 is a refractive index of the substrate 16 and the transparent adhesive agent 10, n2 is a refractive index of the transparent rod 11, n3 is a refractive index of the atmosphere, and has a relationship of n2> n1> n3.

FIG. 1B is a view illustrating a wide viewing angle device for a non-luminous display according to another embodiment of the present invention. The non-light emitting display wide viewing angle device of FIG. 1B is formed on the transparent rod 11 in the wide viewing angle device of FIG. 1A. The transparent protective plate 13 is attached using the transparent adhesive 12, and an opaque film 18 is further formed between the transparent rods 11.

A wide viewing angle device for a non-luminous display according to another embodiment of the present invention shown in Figure 1b, the transparent substrate 16, the visible light (19) output from the non-luminous display (not shown) is incident; The output light 19 of the non-luminescent display, which is fixed on the substrate 16 by the transparent adhesive 10 having the same refractive index as the refractive index n1 of the substrate 16 and is incident through the substrate 16, has a large angle. The plurality of transparent rods 11 by the plurality of transparent rods 11 arranged in parallel to serve as the optical refraction portion and the transparent adhesive 12 having the same refractive index as the refractive index n1 of the substrate 16. And a protective plate 13 made of a transparent material for outputting light output from the plurality of transparent rods 11 to the outside, and each transparent rod in a direction in which the light 19 output from the non-luminescent display is incident ( 11) the reflection from the surface of the plurality of transparent rods 11 Has a non-transparent film 18 for blocking incident to the other edge of the transparent rod which is adjacent the light is formed.

An operation of the non-light-emitting display wide viewing angle device according to another embodiment of the present invention configured as described above will be described with reference to FIG. 1B.

In the wide viewing angle device for a non-luminous display according to another embodiment of the present invention, the visible rays 19 output from the non-luminous display (not shown) are refracted at different angles by the plurality of transparent rods 11. The refracted visible rays are refracted once more at the interface between the protective plate 13 of the transparent material and the atmosphere, thereby obtaining a wider viewing angle. Here, the opaque film 18 formed between the transparent rods 11 in the direction in which the light output from the non-luminescent display is incident is directed to the edges of other transparent rods where the light reflected from the surfaces of the plurality of transparent rods 11 is adjacent. It is to block the incident and a detailed description thereof will be described later with reference to FIGS. 4 to 5.

N1 is the refractive index of the board | substrate 16, the transparent adhesive agents 10 and 12, and the protective plate 13, n2 is the refractive index of the transparent rod 11, and n3 is the refractive index of the atmosphere.

FIG. 2A illustrates a refraction phenomenon that occurs when a plurality of light rays coming from a light source (not shown) enter another medium having a curved surface. Assuming the light source is far enough away, the light coming from the light source can be treated as a number of parallel rays. When the parallel rays 22 enter the medium 21 having the refractive index n 1 from the medium 20 having the refractive index n 1, the incident light rays are refracted at different angles if the boundary between the two media is curved. At one point they come together. The distance from the boundary of two media having different refractive indices to the position 23 where the light rays converge is called the focal length f. This focal length f is expressed by equation (1).

Where f is the focal length and r is the radius of the imaginary circle formed by the surface.

FIG. 2B shows the refraction phenomenon that occurs when the cross section of the medium 26 having the refractive index n 2 is limited to a circular space. When light ray 27 is incident from medium 25 having a refractive index of n1 to medium 26 having a refractive index of n2, primary refraction occurs. Assuming refractive index n2 is greater than refractive index n1, light ray 27 is refracted in the direction of the center of circular medium 26. Also, when the primary refracted light exits from the circular medium 26 to a medium having a refractive index of n1, secondary refraction occurs at the interface, and the refraction occurs in a direction in which a plurality of light rays converge at one point. Multiple rays 27 traveling in parallel cause two refractions while passing through a high refractive index medium 26 having a circular cross section. The light refracted twice converges to a point with a shorter focal length than in the case of FIG. θ _r Spreads with). In addition, the larger the difference between the refractive indices of the two media, the shorter the focal length f, and thus the divergence angle of the light increases. On the other hand, the smaller the difference in refractive index, the longer the focal length f and the divergence angle of the light decreases.

3 is a view showing a liquid crystal display with a wide viewing angle device according to the present invention. On the polarizing film 30 of a liquid crystal display, the some transparent rod 32 provided with the opaque film 36 is attached using the transparent adhesive 31 of refractive index n1. A glass substrate 33 having a refractive index of n1 serving as a protective plate is attached to the plurality of transparent rods 32 by using the transparent adhesive 35. In the liquid crystal display, since the light passing through the liquid crystal (not shown) and the polarizing film 30 is unevenly distributed according to the azimuth angle, the luminance and the color contrast are increased as the observer moves away from the direction perpendicular to the polarizing film 30. There is a different problem.

The wide viewing angle device of the present invention composed of the transparent adhesives 31 and 35 of FIG. 3, the plurality of transparent rods 32 with the opaque film 36, and the glass substrate 33 is in a vertical direction from the polarizing film 30. Refracting rays 34 are refracted and spread out at a wide angle past the focal point. In this case, it is preferable that the width of one pixel and the diameter of the transparent bar are designed to be the same and aligned with each other. Since the surface of the transparent bar 32 is curved, parallel rays of light constituting the luminous flux meet with the surface of the transparent bar 32 at different angles. Therefore, each ray is refracted at a different angle, and the reflectance on the surface of the transparent rod 32 increases as the angle with the normal at the incident position increases.

4A is an incident angle ( θ ₁ When the) is small and shows the phenomenon appearing on the surface of the transparent rod 32, the reflectance of the light is low, most of the light is refracted into the transparent rod 32. 4b is the incident angle ( θ ₃ In the case where the) is large, the phenomenon appearing on the surface of the transparent rod 32 is shown, and the light reflectance is high and most of the light is reflected to the outside.

As shown in FIGS. 4A and 4B, the incident angle is increased as the incident light enters a position closer to the center of the circle 40 representing the cross section of the transparent rod 32. θ ₁ ) Is smaller and the incident angle ( θ ₃ ) Becomes large. Therefore, most of the light incident to the edge of the transparent rod 32 is at the surface θ ₃ It is reflected with and enters into the neighboring transparent rod.

FIG. 5A illustrates a phenomenon that occurs when the phenomenon shown in FIG. 4B occurs when the opaque film 36 is not present in the wide viewing angle device attached to the liquid crystal display illustrated in FIG. 3. In the absence of the opaque film 36 as shown in FIG. 5A, the reflected light 50 is totally reflected at the interface between the transparent substrate 33 and the atmosphere, or mixed with light emitted from other neighboring pixels or at an undesired position. It causes the problem of light being emitted. In order to solve this problem, as shown in FIG. 5B, an opaque material film 54 is applied between the individual transparent rods 32 to block the light 52 incident to the edges of the transparent rods 32.

6A is a diagram illustrating a structure of a general optical waveguide display. The core 61 is disposed between the upper cladding 62 and the lower cladding 63, and the lower cladding 63 is made of a material whose refractive index changes when an electric field is applied. An upper portion of the upper cladding 62 includes an absorbing layer 64 and an upper electrode 65, and a scattering layer 60 and a lower electrode 66 are positioned below the lower cladding 63.

In the optical waveguide display configured as described above, when an electric field is applied between the upper electrode 65 and the lower electrode 66, the refractive index of the lower cladding 63 is changed so that the light traveling through the core 61 is lower the cladding 63. The light scattering layer 60 reaches the scattering layer 60 and is uniformly scattered in almost all directions in the scattering layer 60, and the scattered light passes through the transparent lower electrode 66 and is output to the outside of the screen.

FIG. 6B is an enlarged view of portion A of FIG. 6A. Since light incident on the scattering layer 60 is scattered in almost all directions as shown in FIG. 6B, the amount of light output to the outside of the screen is scattered layer 60. ) Is very small compared to the amount of light incident on the light, resulting in a low light efficiency.

7A is a view showing an optical waveguide display to which a wide viewing angle device according to the present invention is attached. In FIG. 7A, the roles of the upper electrode 75, the lower electrode 76, the absorbing layer 74, the upper cladding 72, the lower cladding 73 and the core 71 are the same as those of FIG. 6A, and in FIG. 7A. The wide viewing angle device 70 according to the present invention is positioned under the transparent lower electrode 76 instead of the scattering layer 60 of FIG. 6A. FIG. 7B is an enlarged view of a portion B of FIG. 7A. Referring to FIG. 7B, a plurality of light rays passing parallel to each other through the lower cladding 73 may pass through a wide viewing angle device through the lower electrode 76 of a transparent material. 70).

The plurality of incident light rays 77 are refracted at various angles while passing through the transparent adhesive 81, the transparent rod 82, and the glass substrate 83, thereby creating a wide viewing angle. In this case, since there is little light reflected inside the screen, the light efficiency output to the outside is very high. In this case, since the light beam is obliquely entered without entering the wide viewing angle device 70 vertically, the light beam does not deviate greatly from the position of the designated pixel even after the light incident on the edge of the transparent bar 82 is reflected. Thus, in this case, an opaque film is not necessary.

FIG. 8A is a view for explaining a wide viewing angle device for a non-light emitting display according to another embodiment of the present invention, and FIG. 8B is a front view of FIG. 8A.

FIG. 8A has a structure in which the wide viewing angle device of FIG. 1 has a plurality of transparent rods 11 of one layer while overlapping the plurality of transparent rods of two layers. The light from the non-luminescent display is refracted up and down through the plurality of transparent rods 92 at the bottom, and is refracted left and right through the plurality of transparent rods 90 at the top. Therefore, the wide viewing angle device of FIG. 8A has a feature of obtaining a wide viewing angle in up, down, left, and right directions. FIG. 8B is a front view of FIG. 8A, in which a plurality of transparent rods 90 at the top and a plurality of transparent rods 92 at the bottom are arranged orthogonal to each other, and opaque films 94 and 96 coated between the individual transparent rods are disposed. Forms a net shape. The transparent rod regions 98 existing between the top opaque film 94 and the bottom opaque film 96 are preferably aligned with the individual pixels of the bottom non-luminescent display.

As described above, the wide viewing angle device for the non-luminous display according to the present invention has an advantage of increasing the viewing angle and light efficiency of the non-luminous display such as a liquid crystal display and an optical waveguide display.

Claims (5)

A transparent substrate on which light output from the non-luminescent display is incident; And A plurality of parallel arranged transparent rods for refractively outputting the output light of the non-luminescent display incident on the substrate by a transparent adhesive having a refractive index similar to the refractive index of the substrate at a large angle A wide viewing angle device for a non-luminous display, characterized in that it comprises a light refracting portion. The wide viewing angle device of claim 1, wherein the transparent rod is an optical fiber made of a transparent material. The method of claim 1, further comprising a protective plate made of a transparent material for outputting the light output from the optical refraction portion coupled to the optical refraction portion by a transparent adhesive having a refractive index similar to the refractive index of the substrate to the outside. Wide viewing angle device for non-luminescent display. The non-transparent material of claim 1, wherein light reflected from the surfaces of the plurality of transparent rods is prevented from entering the edges of adjacent transparent rods between the transparent rods in the direction in which the light output from the non-luminescent display is incident. A wide viewing angle device for a non-light-emitting display, characterized in that a further film is formed. According to claim 1, wherein the optical refraction portion has a plurality of transparent rods of two layers having a superimposed structure so as to be orthogonal to each other so as to obtain a wide viewing angle in the four directions of up, down, left, and right, wherein each of the plurality of transparent rods A non-light-emitting display wide viewing angle device, characterized in that the film of opaque material is further formed to block the light reflected from the transparent rod surface of the adjacent transparent rod incident.