KR20110016423A - Luminance inhancement optical substrate with anti-interference-fringe structure - Google Patents

Abstract

PURPOSE: An improved luminance optical substrate with an anti-interference-fringe structure reduce an interference-fringe in low price. CONSTITUTION: An optical substrate having unevenness comprises: a substrate; an light input side(52) on one side of the substrate; a uneven light output side(54) on the backside of the substrate; and prisms which are arranged in parallel with the light output side.

Description

Luminance reinforcing optical substrate with interference fringe prevention structure {LUMINANCE INHANCEMENT OPTICAL SUBSTRATE WITH ANTI-INTERFERENCE-FRINGE STRUCTURE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical substrate having an uneven surface, and more particularly to an optical substrate for luminance enhancement for use in a flat panel display having a flat light source.

Flat panel displays are commonly used in televisions, computers, and mobile devices (mobile phones, PDAs, etc.). LCD is a type of flat panel display, which uses LC (liquid crystal) module with pixel array.

1 is an example of an LCD, wherein the LCD 10 includes an LC module 12, a flat panel type backlight module 14, and a plurality of optical films between the LC module 12 and the backlight module 14. The LC module 12 includes liquid crystals disposed between two transparent substrates and a control circuit forming a two-dimensional pixel array. The backlight module 14 is a flat light source and includes an edge type light source and a planar light source as shown in FIG. 1, which is a linear light source 16 disposed at an edge of the light guide plate 18. The reflector 20 is installed to emit light from the light source 16 to the edge of the light guide plate 18. The light guide plate has a configuration for dispersing light through a flat top surface facing the LC module 12, where the bottom surface opposite the LC module 12 is a tapered plane that reflects or scatters light. The vertical diffusion films 22 and 24 of the optical film diffuse light emitted from the plane of the light guide plate 18. The optical films have upper and lower uneven surfaces and the optical substrates 26 and 28 of the present invention, and these optical substrates redistribute the light so that the light emitted therefrom is vertical. Optical substrates 26 and 28 are known in the art as brightness reinforcing films, light redirecting films, and diffusion films. Light entering the LC module 12 through the optical films has a relatively strong intensity uniformly and vertically throughout the plane of the LC module 12. The LCD 10 is used for televisions, notebooks, monitors, mobile phones, PDAs, cameras, and the like.

There is a growing need to reduce LCD power consumption, thickness and weight without compromising image quality. Therefore, it is necessary to reduce the power consumption, weight and thickness of the backlight module and various optical films. In this regard, many lighting technologies have been developed to reduce power consumption without harming luminance. In some cases, the design of the backlight module 14 with the light source 16, the reflector 20 and the light guide plate 18 may be improved, while the diffusion films 22 and 24 and the brightness enhancement films 26 and 28 may be used. Technology has also been concentrated on improving.

The brightness enhancement films 26 and 28 of the LCD 10 enhance the brightness by using a prism structure to send light to an optical axis perpendicular to the display, and by using a display that uses less power to generate a desired level of optical axis illumination. To this end, prism grooves, lenticular grooves, or pyramids are arranged on the light output surface of the luminance reinforcing film to change the film / air interference angle with respect to the light exiting from the film, and the obliquely incident light is emitted vertically. To this end, the two brightness enhancement films used in many LCDs are rotated with respect to each other about an axis perpendicular to the film plane so that the grooves of each film are 90 degrees relative to each other, so that the light along the two planes orthogonal to the light output plane is Let it flow.

Many efforts have been made to develop the uneven surface of the luminance reinforcing film. 2 shows the structure of various conventional luminance reinforcing films. The upper surface, which is the light output surface of the brightness enhancement film, is uneven, and the light input surface of the lower surface is a flat surface. When using a brightness reinforcement film for LCD, the flat bottom surface is covered with the uneven surface of another brightness reinforcement film, and the optical interference between the flat surface of the upper reinforcement film and the uneven surface or flat surface of the lower brightness reinforcement film is repeated on the display (black and white repeating). Visible defects in the form of interference fringes. The effect on the image due to interference fringes, defects, stains, or irregularities may be covered by the diffusion film 22 on the luminance reinforcing film 26 of FIG.

In order to reduce the thickness of LCD optical films, there have been many attempts to reduce the number of optical films from four to three. In this regard, although the lower diffusion film 24 and the brightness enhancement film 28 are maintained in separate structures, the functions of the upper diffusion film 22 and the brightness enhancement film 26 are combined into one hybrid film structure. Triple-layer displays are widely used in portable devices, helping to reduce the overall size of these devices.

There have been many efforts to develop a hybrid type luminance reinforcing film. As shown in FIG. 3, US Pat. No. 5,995,288 introduces a coating of a particle layer on the bottom surface opposite to the top surface of the uneven surface of the optical substrate. As shown in FIG. 4, US Pat. No. 5,598,280 introduces a method of forming small protrusions on the bottom surface of the optical substrate to improve the uniformity of luminance. Another technique is to change the prism structure of the uneven surface of the optical substrate. As shown in FIG. 5B, U.S. Patent No. 6,798,574 introduces a technique of diffusing light at a wider angle by forming fine protrusions on the surface of the prism of the uneven surface of the optical substrate.

However, the hybrid type luminance reinforcing film described above is complicated in structure and requires a lot of manufacturing costs, and is inefficient in adjusting light at a desired angle.

In addition, since there is no separate diffusion film between the bottom surface of the LC module and the uneven surface of the upper hybrid luminance reinforcing film, an interference pattern in which a black and white pattern is repeated may be generated. The upper structure of the luminance reinforcing film and the pixel array of the LC module are known to cause interference fringes or moire fringes.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive optical substrate having a surface structure that reduces interference patterns while reinforcing luminance.

An optical substrate of the present invention for achieving the above object, the substrate; An optical input surface on one side of the substrate; Uneven light output surface opposite the substrate; And an elongated prism array disposed side by side on the light output surface, wherein the prism has a horizontally deformed section. In the optical substrate of the present invention, the prism is meandering from above, where the prisms are arranged side by side, and the mountains of adjacent prisms can be parallel. In addition, the spacing between adjacent mountains may be the same in the x-z plane. In addition, each prism may have a sinusoidal shape. Moreover, it can also be winding to a certain wavelength of a prism. In addition, each prism can be tortuous in any form, the height of the mountain is constant along the prism, or the height of the mountain can change along the prism, in which case the height of the mountain changes regularly or irregularly. In addition, when the height of the mountain changes, structural irregularities may be distributed on the light output surface. At this time, there is a prism formed of a flat surface on the light output surface, and the irregular portion may have a structure corresponding to the non-flat section. Alternatively, the irregular portions may have a structure such as a structural defect expected in the manufacturing process of the light output surface, or the irregular portions may be regularly or irregularly distributed on the light output surface. Also, the prism may have hills and valleys, and irregular portions may correspond to flat valleys or hills. Meanwhile, structural irregularities may be distributed on the light input surface in the optical substrate of the present invention. In addition, the substrate may have a base layer and an uneven layer, the base layer may have a flat bottom surface constituting the light input surface and an upper surface supporting the uneven layer, and the uneven layer may have a top surface constituting the uneven light output surface.

The present invention also includes a display module for showing an image in accordance with the image data; A backlight module illuminating the display module; And a lighting reinforcement module positioned between the display module and the backlight module to enhance illumination brightness of the display module and having the optical substrate of claim 1 as the first optical substrate. At this time, the illumination reinforcing module further includes a second optical substrate having an uneven type light output surface and an optical input surface, the uneven type light output surface of the first optical substrate is adjacent to the light input surface of the second optical substrate, It is preferred if the prisms of the two optical substrates are arranged crosswise about the z-axis so that they are orthogonal to each other. In this case, it is preferable that the uneven type light output surface of the second optical substrate is similar to the uneven type light output surface of the first optical substrate. In this case, there may be no separate diffusion layer between the light input surface of the second optical substrate and the backlight module, or there may be no separate diffusion layer between the uneven light output surface of the first optical substrate and the display module.

The invention also provides a flat panel display described above; And a control device which sends image data to the flat panel display in order to show an image suitable for the image data.

1 is an exploded perspective view of a conventional LCD;
2 is a perspective view of a conventional optical substrate having a different surface structure;
3 to 5 are cross-sectional views and perspective views of a conventional hybrid luminance enhanced optical substrate;
6A is a perspective view of an optical substrate having an uneven surface in accordance with the present invention;
6B-F are photographs showing simulation results of light diffusion effects along two orthogonal vertical planes of an optical substrate at various waveforms;
7A is a perspective view of an uneven surface of which a mountain height is changed according to another example of the present invention;
7B-F are photographs showing simulation results of light diffusion effects along two orthogonal vertical planes of optical substrates of various heights;
8A is a perspective view of an uneven surface in which irregularities are distributed according to another example of the present invention;
8B is a perspective view of an uneven surface in which irregularities are distributed according to another example of the present invention;
8C to G are photographs showing simulation results of light diffusion effects along two orthogonal vertical planes of an optical substrate having irregular portions distributed therein;
9 is a SEM photograph of a prototype optical substrate having irregular portions distributed therein and a prism waveform according to another example of the present invention;
10 is an exploded perspective view of an LCD with an optical substrate according to an example of the present invention;
11 is a front view of an electronic device having an LCD panel on which an optical substrate of the present invention is mounted;
12 is a perspective view of an optical substrate on which regular and regular prisms are arranged;
Figure 13 is a perspective view of an optical substrate having structural features combined on the uneven surface in accordance with the present invention.

In the flat panel display of FIG. 10, the backlight LCD 100 includes an LC display module 112, a backlight module 114 in the form of a flat light source, and a plurality of optical films between the LC module 112 and the backlight module 114. . The LC module 112 includes liquid crystals between two transparent substrates and a control circuit forming a two-dimensional pixel array. The backlight module 114 distributes light in a planar shape, and the linear light source 116 is disposed at the edge of the light guide plate 118. A reflector 129 is installed to direct light from the linear light source 116 into the light guide plate 118 through the edge of the light guide plate 118. The light guide plate only needs to have a structure for dispersing light in an upper plane facing the LC module 112, and the bottom surface opposite the LC module 112 may be inclined or scattered light. The vertical diffusion films 122 and 124 forming the optical film diffuse light emitted from the plane of the light guide plate 118. The two diffusion films will be described later in detail, but in some cases, the upper diffusion film 122 or the lower diffusion film 124 may be omitted. In this case, the overall thickness of the LCD 100 is reduced. The diffusion film and the additive film are distinguished from the optical substrate for luminance enhancement described later. Specifically, the diffusion film does not have a prism structure. Diffusion film does not have the function of scattering and scattering the light and increasing the brightness by shining the light toward the display. The optical substrate has a prism structure to provide both light diffusion and luminance enhancement.

Specifically, the optical film of FIG. 6A has one or more optical substrates according to the present invention, which not only diffuses the light, but also redistributes the light so that the light from the film exits perpendicular to the film surface. In the illustrated embodiment, two structurally similar optical substrates 126 and 128 are arranged such that the prism structures are orthogonal. These optical substrates 126 and 128 reinforce luminance while spreading light, and send light to the display. Light entering the LC module 112 through this optical film is uniform across the surface of the LC module 112 and has a relatively strong intensity. If there are optical substrates 126 and 128, there is no need to arrange a separate diffuser plate between the LC module 112 and the upper optical substrate 126. In addition, the presence of the optical substrates 126 and 128 reduces the occurrence of interference fringes between the substrates and between the upper substrate and the LC module 112. On the other hand, even if only one of the optical substrates 126 and 128, for example, only the lower optical substrate 128, the interference fringes and the light diffusion effect can be acceptable.

The optical substrates of the present invention can be used in LCDs such as televisions, notebook computers, monitors, portable devices such as mobile phones, digital cameras, PDAs, and the like.

Although the light source 116 has been described as being disposed at the edge of the light guide plate 118 of the backlight module 114, other types of light sources, such as arranging an LCD array at the edge or surface of the light guide plate, are also within the scope of the present invention.

The optical substrate 50 of FIG. 6A may be used for the optical substrates 126 and 128 of FIG. The optical substrate 50 has a light input surface 52 and a light output surface 54, the light output surface having a prism structure in which an elongated elongated prism 58 is arranged in a side by side arrangement 56. Prism 58 draws a gentle curve. On the other hand, a plurality of small prism sections are connected to each other in a specific curved section of the prism, it may take a whole winding shape. In the illustrated embodiment, the light input surface 52 is smooth, planar and polished rather than irregular. The light input surface 52 may be dispersed, frosted or mat-like on the surface as introduced in US Patent Application 12 / 832,021, filed Jul. 7, 2010. The illustrated light output surface and the light input surface are generally parallel to each other.

In the embodiment of FIG. 6A, the prism 58 array 56 is arranged with the peaks 60 and valleys 62 next to each other. A wavy surface is formed between adjacent hills 60 and valleys 62. These wavefronts follow a sinusoidal shape with constant wavelength and amplitude, but may be irregular in wavelength or amplitude (see FIG. 9). The vertex of the mountain is at right angles, and the mountain or valley can be constant or similar in height or depth to the substrate plane. The cross-sectional shape of the prism 58 in the x-z plane is constant. On the other hand, the horizontal waveform may be irregular and the wavelength or amplitude may be variable.

The pitch, the spacing between adjacent hills / vales, is constant in the x-z plane. In this case, the light output surface and the light input surface are parallel to each other as a whole of the optical substrate.

Hereinafter, a description will be given with reference to the x, y, z rectangular coordinate system. In FIG. 6A, the x axis is transverse in the direction crossing the hill and the valley, and the y axis is perpendicular to the x axis in the longitudinal direction of the prism 58. The longitudinal direction of the prism is the direction in which the mountain 60 extends from the end of the prism 58 to the end, and the prism is serpentine about the y axis. The light input surface 52 is in the x-y plane. Structurally, the x and y axes follow the orthogonal edge of the substrate. The z axis is orthogonal to the x axis and the y axis. The edge showing the ends of the arrays 56 of prisms 58 arranged side by side is in the x-z plane in FIG. 6A. The cross section of the prism 58 is taken in the x-z plane at several places along the y axis. The horizontal direction is the x-y plane and the vertical direction is the z direction.

The substrate 50 has a two-layer structure, wherein the upper surface layer 68 forms a light output surface 54, and the lower base layer 66 forms a flat light input surface 52. The two layers are bonded to each other to form a substrate 50. As is well known, the substrate may be a single layer structure instead of a two layer structure, which is also within the scope of the present invention. The optical substrate 50 may have a single structure in which the base is integral with the prism structure forming the surface.

The surface layer 68 and the base layer 66 may be made of different materials. The surface layer 68 may be made of a transparent material, preferably a polymerizable resin which is a resin that is cured by ultraviolet rays or visible light. Generally, the surface layer 68 is formed by coating a composition comprising a polymerizable, crosslinkable resin on a master mold or master drum and then curing. The base layer 66 is usually made of polyethylene terephthalate (PET), but may also be made of a transparent material such as the surface layer 68. The base layer 66 has a thickness necessary to impart structural stability as a final luminance reinforcing film.

The dimensions are as follows:

Thickness of the base layer = several tens of micrometers to several mm

Height of acid measured from top of base layer = tens to hundreds of μm

Depth of valley from top of base layer = 0.5 μm to several hundred μm

Peak angle of the mountain = 70 degrees to 110 degrees

Pitch between acids = tens to hundreds of micrometers

Wavelength W of the horizontal corrugated prism W = several tens of micrometers to several mm

Horizontal strain D (twice the amplitude of prism) = tens to hundreds of μm

The peak height may vary for each prism at the light output surface of the optical substrate (see FIGS. 13 and 7A). The height of the mountain can change regularly or arbitrarily. The change in the height of the mountain in FIG. 7A is regular and is in the form of a sine wave. Mountain height changes may be irregular. These irregularities can be a kind of structural defect that occurs during manufacturing, such as the non-flat portion of the prism structure (see Figure 8a). These structural irregularities are regularly or irregularly distributed on the light output surface. Irregular portions on the light output surface may mask defects that can be recognized by a user due to structural defects that may occur during manufacturing. See US patent application Ser. No. 11 / 825,139, filed Jul. 2, 2007, for defect shielding effects of structural irregularities.

Of light diffusion effect  Computer simulation

A computer simulation model was taken for the trend analysis of the light diffusion effect with two luminance enhanced optical substrates orthogonally arranged. In general, as will be described in detail later, for trend analysis, only one substrate has a corrugated prism structure, and the prism height is comfortable and there are flat irregular portions. Only one optical substrate can easily determine the effect of the uneven surface. The upper substrate has a straight triangular prism on one side and the opposite surface is smooth or smooth. The lower substrate has corrugated prisms on only one side, but with varying mountain heights and flat irregular areas. The uneven surface of the lower substrate is adjacent to the flat surface of the upper substrate, and the opposite surface of the lower substrate is a smooth surface. Light enters the smooth light input surface of the lower substrate. The light diffusion effect of the light output surface of the upper substrate is obtained by using a simulation model. Reflectors, light guide plates, or other elements were not considered.

The light diffusion effect along the x-z and y-z planes of the optical substrate 50 having a constant wavelength W = 100 μm and a different horizontal strain D with different waveforms was investigated by computer simulation. The combination of the upper optical substrate 70 and the lower optical substrate 50 having a straight uniform prism 71 array was simulated (see FIG. 12). The upper substrate 70 and the lower substrate 50 were z The x axis of the upper substrate 70 coincided with the y axis of the lower substrate 50 by rotating 90 degrees about the axis. The bottom surface of the upper substrate 70 is smooth to face the uneven surface of the lower substrate 50. The peak of the upper substrate 70 has a pitch of 50 µm and a vertex angle of 90 degrees, and the peak of the peak of the upper substrate 70 is also similar to the peak angle. Lambertian light enters the light input surface of the bottom substrate. The light diffusing effect can be easily achieved with only one of the two optical substrates having a wave shaped prism structure or changing the height and flat irregularities in other simulations.

6b to f show the results of the simulation for the lower optical substrate 50 having a wave shaped prism having a wavelength W of 100 μm and a strain D of 0, 10, 20, 30, and 40 μm. The left figure shows the light diffusion effect in the x-z plane of the lower substrate 50 having the prism structure of Fig. 6A, and the right figure shows the light diffusion effect in the y-z plane of this substrate. From the simulation results, a clear light diffusion effect trend can be seen, and the uniformity of the distribution of the diffused light of the upper substrate 70 is improved as the strain D increases. From the simulation results, it can be seen that the diffused light on the light output surface increases rapidly in the x and y directions as the strain D increases. The output light is diffused more in the transverse direction (x-z plane) than in the longitudinal direction (y-z plane). When W = 0 (FIG. 6B), the output light is more concentrated and does not diffuse.

For the simulation trend analysis according to the mountain height, in the optical substrate 72 of FIG. 7A, only the mountain height of each prism is changed. The rate of change of the height of this prism is V.

Computer simulations were performed to analyze the light diffusion effect in the x-z and y-z planes of the optical substrate 72 having a V height change rate. Similarly, the combination of the upper optical substrate 70 and the lower optical substrate 72 in which the prism 71 is arranged in a straight line and is regularly arranged, the upper substrate 70 and the lower substrate 72 with respect to the z axis When rotated 90 degrees, the x axis of the upper substrate 70 coincided with the y axis of the lower substrate 72. Simulation conditions are similar to the simulations of FIGS. 6B-F. The bottom surface of the upper substrate 70 facing the uneven surface of the lower substrate 72 is smooth. The upper substrate has a pitch of 50 µm, the vertex angle is 90 degrees, and the dimensions of the lower substrate are similar. Lambertian light enters the light input surface of the bottom of the lower substrate.

7B-F show the results of the simulation of the lower optical substrate 72 having the acid height strain V = 0, 10, 20, 30, 40 μm. The left figure shows the light diffusion effect in the x-z plane of the lower substrate 72 having the prism structure of FIG. 7A, and the right figure shows the light diffusion effect in the y-z plane of this substrate. From the simulation results, it can be seen that the light diffusion effect does not change significantly even if the acid height strain V increases. The uniformity of the distribution of the diffused light of the upper substrate 70 only increases slightly even if the strain V is large. From the simulation results, it can be seen that the diffused light on the light output surface does not change greatly in the x and y directions even when the strain V is large. The output light is concentrated even if the acid height strain V changes, and does not diffuse much.

8A shows an example of an optical substrate 76 having only irregularities 78 in a prism for simulation trend analysis. To simplify the simulation model, it was considered to have a regular, straight prism with a flat gap 82 between the prisms 84. In FIG. 8B, the area ratio of the flat irregular portion to the total area is adjusted using b / a = R. 8c to g show trends of light diffusion effects of structures with R = 0, 2.5, 5, 10, and 20%, respectively.

Computer simulations were performed to analyze light diffusion effects in the x-z and y-z planes of the optical substrates 80 having different Rs. Similarly, the combination of the upper optical substrate 70 and the lower optical substrate 80 in which the prism 71 is straight and regularly arranged is simulated. The upper substrate 70 and the lower substrate 80 with respect to the z axis are simulated. When rotated 90 degrees, the x axis of the upper substrate 70 coincided with the y axis of the lower substrate 80. Simulation conditions are similar to the simulations of FIGS. 6B-F. The bottom surface of the upper substrate 70 facing the uneven surface of the lower substrate 80 is smooth. The upper substrate has a pitch of 50 µm, the vertex angle is 90 degrees, and the dimensions of the lower substrate are similar. Lambertian light enters the light input surface of the bottom of the lower substrate.

8C-G show the results of the simulation for the lower optical substrate 80 at R = 0, 2.5, 5, 10, 20%. The left figure shows the light diffusion effect in the x-z plane of the lower substrate 80 having the prism structure of FIG. 8B, and the right figure shows the light diffusion effect in the y-z plane of this substrate. From the simulation results, it can be seen that the light diffusion effect does not change significantly even if the acid height R increases. However, even if the R of the diffused light distribution of the upper substrate 70 is large, it hardly changes. From the simulation results, it can be seen that the diffused light of the light output surface hardly changes in the x and y directions even if R is large. The output light is concentrated even if R changes, and does not diffuse very much.

On the basis of various types of trend analysis according to the abnormal waveform prism, the change in the height of the mountain, and the flat irregularity, the following light diffusion effects were observed. The total diffused light at the output surface of the upper optical substrate increases rapidly as the horizontal strain D of the corrugated prism increases. The total diffused light of the upper optical substrate is only slightly increased even if the acid height change rate V increases. Therefore, the horizontal strain D of the waveform prism greatly influences the light diffusion. The ratio R of the flat irregular portion has little effect on the rate of change of the horizontal strain or the height of the mountain. From the above analysis, it can be seen that by combining various methods, interference fringes can be reduced without harming diffusion.

The above simulation does not consider the effects of regularly or irregularly combining the horizontal strain D, the change in the height of the mountain V, and the ratio R of the flat irregular portion. Prisms were parallel in all simulation structures. Proper application of the horizontal strain D, the change in the height of the mountain V, and the ratio R of the flat irregular portion can be expected to improve the diffusion effect.

Experiment result

The prototype optical substrate according to the present invention was produced by calculating and distributing the horizontal strain, the height change rate, and the ratio of the flat irregular portion. 9A is a SEM photograph of the waveform prism and the flat irregular portion having various sizes. 9B is an enlarged photograph of FIG. 9A. In the optical substrate 77 of FIG. 13, the waveform prism is parallel as shown in FIG. 6A, and the change in the height of the mountain is shown in FIG. 7A, and the flat irregular portion 78 is shown in FIG. 8A.

While observing the interference fringe, the prism is straight, so that one side has a waveform prism strain, a change in the height of the mountain, and no flat irregularities, and the other side is a flat top optical substrate. This upper substrate is placed on the prototype optical substrate of the present invention. The prototype lower substrate according to the present invention is laminated on the upper straight prism optical substrate in a computer simulation arrangement. The backlight of FIG. 10 is illuminated on the stacked substrate. On the upper light output surface of the upper linear prism optical substrate, an interference fringe, a pattern in which black and white is repeated, is observed.

Table 1 shows the performance of the nine examples of lower prototype optical substrates. Based on the level 5 interference fringes (0-5 scale) shown in the reference case in which two straight prism films were stacked crossing each other. The gain is the ratio of the luminance of each embodiment to the luminance of the light guide plate.

Example Wave Prism
Horizontal strain Mountain height
Rate of change (㎛) flatness
Irregular part
(Μm) Interference
level
benefit Average (μm) (Μm) One 25 55 <10 2.1 0 1.55 2 24 48 <10 4.3 0 1.51 3 26 39 <10 8.3 0 1.46 4 12 21 <10 10.4 One 1.46 5 29 54 <10 1.1 0 1.54 6 28 53 <10 2.5 0 1.54 7 30 55 <10 0.1 0 1.54 8 25 38 <10 0 1.5 1.55 9 28 45 <5 0 0 1.54

In Examples 4 and 8 the levels were reduced from 5 to 1 and 1.5. In all other examples there was no interference fringe. Example 4 mixes a strain of 12 μm with a flat irregularity ratio of 10.4%, showing significant improvement and better performance in interference fringes compared to Example 8, which has a strain of 25 μm with no irregularities. In other words, it can be seen that the irregular portion is useful for light diffusion to remove the pattern. However, as shown in Examples 1 to 4, the larger the area of the flat irregular portion, the lower the gain. To maintain the gain without loss, the flat irregularities must be specifically arranged, and the range of the flat irregularities must be adjusted in some cases. In general, the effect of the flat irregular portion on the interference fringe depends on the total area, number, shape, size and position of the flat irregular portion.

It is not essential to combine the rate of horizontal strain, peak height change, and the ratio of irregularities to reduce interference fringes properly. For example, an optical substrate may have only a horizontal strain rate without a change in acid height and irregularities. As shown in Example 9, if the horizontal strain is 28 µm and the height change rate is small, the interference fringes can be eliminated without any irregularities. In addition, when the change in the height of the mountain becomes zero, the effect of removing the interference fringe can be seen even if only a flat irregular portion is a little.

Uneven surface according to the present invention can be made by a variety of techniques, for example, by using a rigid tool to precisely mold the irregular prism shape can be made. A hard tool is an example of a very small diamond tool installed in a CNC (computer numerical control) machine. You can make a few variations on these machines or install drilling tools to create prisms with different irregularities. For example, conventional STS (Slow Tool Servo), FTS (Fast Tool Servo), ultrasonic vibration device and the like. U.S. Patent No. 6,581,286 introduces an example of making a groove in an optical film by a screw processing method using FTS. The tool can be mounted on a lathe to make the peak of the peak constant with respect to the x-z plane along the y direction of the prism. By using this device to form a surface in the mold while increasing the degree of freedom, the uneven surface of the optical substrate described above can be made.

The optical board is formed directly using the original plate, or the optical board is formed by duplicating the right plate with an electric shareholder. The shape of the mold is in the form of a belt, drum, plate, cavity. Molds are used to form prismatic structures on substrates by hot embossing, ultraviolet or thermoset processes. Molds are also used to mold optical substrates by injection molding. The substrate or coating material is an organic, inorganic or hybrid light transmitting material and may contain diffused, birefringent, refractive modified particles.

A more detailed description of the method of forming a substrate having an uneven surface is described in US Pat. No. 7,618,164.

The optical substrates 50, 72, 80, and 77 of the present invention have an uneven prism light output surface, and combine an elongated prism with a deliberately made irregular portion and a prism acid change rate, for example, when used in an LCD. Reduce interference fringes and mask user visible defects. The LCD provided with the optical substrate of the present invention can be used for an electronic device. As shown in FIG. 11, the LCD 100 according to the present invention is installed in an electronic product 110 such as a PDA, a mobile phone, a TV, a monitor, a portable computer, a refrigerator, and the optical substrate described above is installed in the LCD 100. . The electronic device 110 includes a control panel including a housing, a user interface 116 such as a key or a button, a controller 112 for managing image data directed to the LCD 100, a processor, an A / D converter, a memory, a storage device, and the like. 118, a power source 114 such as a battery or an external connection jack.

Claims (23)

Board;
An optical input surface on one side of the substrate;
Uneven light output surface opposite the substrate; And
An elongated prism array disposed side by side on the light output surface;
And the prism has a horizontally deformed section. The optical substrate of claim 1, wherein the prism is twisted when viewed from above. The optical substrate of claim 2, wherein the prisms are disposed side by side and the mountains of adjacent prisms are parallel to each other. The optical substrate of claim 2, wherein the spacing between adjacent mountains is the same in the x-z plane. 3. An optical substrate according to claim 2, wherein each prism has a sinusoidal shape. The optical substrate of claim 2, wherein the optical substrate is twisted at a predetermined wavelength of the prism. 3. An optical substrate according to claim 2, wherein each prism is serpentine in any form. 3. An optical substrate according to claim 2, wherein the peak height is constant along the prism. 3. An optical substrate according to claim 2, wherein the height of the mountain varies along the prism. 10. The optical substrate of claim 9, wherein the peak height changes regularly or irregularly. The optical substrate according to claim 9, wherein structural irregularities are distributed on the light output surface. 12. The optical substrate according to claim 11, wherein there is a prism made of a flat surface on the light output surface, and the irregular portion has a structure corresponding to a non-flat section. 12. The optical substrate of claim 11, wherein the irregularities have a structure such as a structural defect expected in manufacturing a light output surface. The optical substrate of claim 11, wherein the irregular portions are regularly or irregularly distributed on the light output surface. 12. The optical substrate of claim 11, wherein the prism has peaks and valleys, and the irregular portions correspond to flat valleys or peaks. The optical substrate of claim 2, wherein structural irregularities are distributed on the light input surface. 3. The substrate of claim 2, wherein the substrate has a base layer and an uneven layer, the base layer has a flat bottom surface forming an optical input surface and an upper surface supporting an uneven layer, and the uneven layer has an upper surface forming an uneven light output surface. An optical substrate, characterized in that. A display module showing an image according to the image data;
A backlight module illuminating the display module; And
And an illumination reinforcement module positioned between the display module and the backlight module to enhance illumination brightness of the display module and having the optical substrate of claim 1 as the first optical substrate. 19. The optical reinforcing module of claim 18, wherein the illumination reinforcing module further comprises a second optical substrate having an uneven light output surface and an optical input surface, wherein the uneven light output surface of the first optical substrate is an optical input surface of the second optical substrate. Adjacent to and intersecting the prisms of these two optical substrates about the z-axis so that they are orthogonal to each other. 20. The flat panel display of claim 19, wherein the concave-convex light output surface of the second optical substrate is similar to the concave-convex light output surface of the first optical substrate. 21. The flat panel display of claim 20, wherein there is no separate diffusion layer between the light input surface of the second optical substrate and the backlight module. 19. The flat panel display of claim 18, wherein there is no separate diffusion layer between the uneven light output surface of the first optical substrate and the display module. A flat panel display of claim 18; And
And a control device which sends the image data to the flat panel display in order to show the image suitable for the image data.

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