TW201514550A - Luminance enhancement optical substrates with anit-interference-fringe structure - Google Patents

Abstract

An optical substrate having a structured light output surface that comprises rows of laterally arranged snaking, wavy or meandering longitudinal prism structures. The prism structures at the light output surface may be viewed as comprising rows of laterally meandering longitudinal prisms and/or sections of curved segments coupled end-to-end to form the overall meandering longitudinal prism structures. The laterally meandering rows of longitudinal prism structures are arranged in parallel laterally (side-by-side), defining parallel peaks and valleys (a facet is defined between each adjacent peak and valley). In one embodiment, the lateral waviness is regular with a constant or variable wavelength and/or wave amplitude (or extent of lateral deformation). The lateral waviness may generally follow a sinusoidal profile, or other curved profile. The structured light output surface may further include varying peak heights along each wavy prism structure and/or pre-defined structural irregularities such as non-facet flat section distributed in the structure surface.

Description

Brightness-enhancing optical substrate with anti-interference fringe structure

The present invention relates to an optical substrate having a structured surface, particularly to an optical substrate that enhances brightness; and more particularly to a substrate for brightness enhancement of a flat panel display having a planar light source.

Flat panel display technology is commonly used in television displays, computer displays, and displays on handheld electronic devices such as mobile phones, personal digital assistants (PDAs, etc.). A liquid crystal display (LCD) is a flat panel display that uses a liquid crystal module having a pixel array to generate a picture.

1 illustrates an LCD display as an example (this display may be modified to include an optical substrate in accordance with the present invention). The backlit liquid crystal display 10 includes a liquid crystal display module 12, a planar light source formed by the backlight module 14, and a plurality of optical films interposed between the liquid crystal module 12 and the backlight module 14. The liquid crystal module 12 includes liquid crystal sandwiched between two transparent substrates, and a control circuit for defining a two-dimensional pixel array. The backlight module 14 provides a planar light distribution, a backlight that extends the light source on a plane or an edged backlight as shown in FIG. 1, which provides a linear light source 16 on the edge of the light guide plate 18. The reflective sheet 20 is used to direct light from the linear light source 16 through the edge of the light guide plate 18 into the light guide plate 18. The light guide plate is structured (eg, a tapered plate and a light reflecting and/or scattering surface defined at the bottom and facing away from the liquid crystal module 12) to distribute and direct light through a plane facing the topmost end of the liquid crystal module 12. The optical film may include an upper diffusion sheet 22 and a lower diffusion sheet 24 that diffuse light from the plane of the light guide plate 18. The optical film further comprises upper and lower structured surfaces, optical substrates 26 and 28 in accordance with the present invention that redistribute the passing light such that light exiting the optical film can be directed closer to the normal to the surface of the optical film. . In the prior art, optical substrates 26 and 28 are commonly referred to as illumination or enhancement brightness diaphragms, light redirecting diaphragms, and directional diffusers. The light entering the liquid crystal module 12 by the combination of the optical films described above is uniformly distributed in the planar region of the liquid crystal module 12 and has a relatively high normal light intensity. The liquid crystal display 10 can be used as a display screen such as a television, a notebook computer, a screen, a portable electronic device such as a mobile phone, a personal digital assistant, a camera, and the like.

The demand for reducing the power consumption, thickness and weight of the liquid crystal screen and maintaining the quality is gradually increasing. Therefore, it is desirable to reduce the power consumption, weight and thickness of the backlight module, and to reduce the thickness of the optical film. In this regard, many light reflection techniques have been developed to reduce power consumption while not compromising the brightness of the display. Some developments are directed to backlight modules to improve overall light output performance (eg, designing a backlight film stack as shown in FIG. 1 that includes light source 16, reflective sheet 20, and light guide plate 18). There are also other developments for the diffusers 22 and 24 and the illumination/brightness enhancement sheets 26 and 28.

In the backlit liquid crystal display 10, the brightness enhancement sheets 26 and 28 adopt a prismatic structure to guide light along a viewing axis (for example, the normal of the display), which enhances the light intensity of the viewer to the display and makes the system use better. The low power produces the desired phase illumination level. Heretofore, the brightness enhancement film has parallel prismatic grooves, grating grooves or triangular prisms on the light exit plane of the film, which can change the angle between the light exiting the film and the film/air interface. And, the light that causes oblique incidence on the other surfaces of the diaphragm is redistributed to a normal that is closer to the exit surface. The brightness enhancement sheet has a smooth light incident surface through which light from the backlight module passes. In the past, many liquid crystal displays used two layers of brightness enhancement sheets (such as the liquid crystal display shown in Figure 1) that rotate about an axis perpendicular to the plane of the diaphragm, such that the grooves of the individual diaphragm layers are nine relative to each other. Ten degrees, this aligns the light to two planes perpendicular to the light output surface.

In the past, many people have been working to develop the structural surface of brightness enhancement sheets. 2 is a diagram showing the structure of a brightness enhancement sheet disclosed in various prior art. The light output surface (the topmost surface shown in the figure) of the brightness enhancement sheet has a structure, and the light incident surface (the bottommost surface in the figure) is flat and smooth (for example, bright). When the brightness enhancement surface is used in a liquid crystal display, its shiny bottom surface is placed over the structural surface of another brightness enhancement sheet, bringing between one of the two brightness enhancement sheets and the other of the bright or structural surfaces Optical perturbations cause undesired visual products such as interfering corrugations in the display (ie, bright and dark interlaced repeating patterns). Effects from unwanted ripples, physical defects, line currents, stains, and unevenness that are undesirable and affecting vision can be masked by the use of an upper diffuser (e.g., diffuser 22 above brightness enhancement sheet 26).

To date, in order to reduce the thickness of the overall optical film in a liquid crystal display, many techniques have focused on reducing the number of optical films from four sheets (e.g., optical films 22, 24, 26, and 28 of Figure 1) to three. In this regard, generally, the lower diffusion sheet 24 and the brightness enhancement sheet 28 are maintained in two separate structures, however the top diffusion sheet and the brightness enhancement sheet are combined into a single hybrid type diaphragm structure. This three-piece display is widely used in handheld electronic devices and notebook computers, and in particular, it is intended to reduce the size of such products.

Many people are committed to developing hybrid brightness enhancement sheets. See Figure 3 of the U. Referring to Figure 4 of U.S. Patent 5,598,280, a method of forming a small convex structure on the underside of an optical substrate is disclosed to improve illumination uniformity. Others have also attempted to adjust the structure of the prismatic surface of the optical substrate. For example, please refer to Figure 5 of U.S. Patent 6,789,574, which provides a fine projection on a prismatic surface for diffusing light in a certain direction at a greater angle.

However, the above-described hybrid brightness enhancement sheet involves a relatively complicated structure and requires a relatively high manufacturing cost. Even the hybrid brightness enhancement sheet is less efficient in guiding light within the desired viewing angle.

In other words, the lack of a hybrid brightness enhancement sheet with a structured surface on the top and individual top diffusion sheets between the undersides of the liquid crystal module may produce interference ripples that exhibit black and white patterns. The surface structure of the brightness enhancement sheet and the pixel array in the liquid crystal module may cause interference ripple or moiré pattern.

There is therefore still a need for a cost effective optical substrate that provides a structured surface that enhances brightness and reduces interference patterns, whether used in brightness enhancement sheets or in liquid crystal modules.

The present invention is directed to an optical substrate having a structured surface that enhances brightness or illumination and reduces display image interference ripple. The substrate of one embodiment of the present invention is in the form of film, paper, sheet, and the like, which may be elastic or rigid, and the substrate has a structured light exiting surface comprising a transversely serpentine or curved longitudinal prismatic structure. The columns that are arranged. In one embodiment, the prismatic structure on the light exiting surface can be viewed as comprising longitudinally curved longitudinal prisms and/or continuous curved sections joined end to end (eg, sections curved in a particular direction, or approximately A curved section in the shape of a C) to form a curved longitudinal prismatic structure in which the assembly is curved. In one embodiment, the laterally curved columns of longitudinal prism structures are arranged in parallel laterally (side by side) and define parallel peaks and troughs (a facet is defined between each adjacent crest and trough). In one embodiment, the transverse undulations are regularly fixed or varying wavelengths and/or amplitudes (or degrees of lateral deformation). The transverse wavy shape may have a shape that is approximately sinusoidal, or other curved shape. In another embodiment, the transverse undulations have random wavelengths and amplitudes. In one embodiment, the peaks have a fixed or similar height and/or a trough having a fixed or similar depth in the plane of the substrate. At a particular cross-section, the highest point between adjacent peaks/valleys can be fixed. In one embodiment, the optical substrate comprises a light incident surface that is unstructured, smooth, flat or smooth. In one embodiment, in the overall optical substrate structure, the light exit surface and the light incident surface are both approximately parallel to each other (ie, an optical substrate that is generally oblique) is not formed.

In another embodiment, the structured light exit surface further comprises a peak height that varies along the wavy prismatic structure.

In a further embodiment, the structured light exit surface further comprises a predefined structural irregularity distributed over the surface of the structure, with or without varying peak heights. The predetermined structural irregularities may be in-kind into the expected structural defects, such as non-facet flat sections in the prismatic structure of the structural surface.

The optical substrate can include a base portion that can be a separate layer of tantalum from the layer having the structured surface, or a prismatic structure that can be integrated or singulated to the surface of the structure. The base portion provides the necessary thickness to provide structural integrity to the final brightness enhancing film.

The disclosure is the best mode for carrying out the invention. The invention has been described herein with reference to various embodiments and drawings. These disclosures are intended to depict the principal principles of the invention and should not be limited. Those skilled in the art will appreciate that various changes and modifications can be made in accordance with the scope of the invention. The scope of the invention should be defined by the scope of the patent application.

The present invention is directed to an optical substrate having a structure that enhances illumination or brightness and reduces interference ripple. In one aspect of the invention, the optical substrate is presented in the form of a film, paper, sheet or the like, which may be elastic or rigid, having a structured light exit surface comprising a serpentine arrangement of lateral alignment , wavy or curved long prismatic structure.

In the context of the present invention, the optical substrate of the present invention can be applied to a display device having display panels which can be flat or curved, rigid or soft, and have a display pixel array. The planar light source provides illumination to cover the area of the pixel array. Accordingly, a display panel having a display pixel that bends the display surface, the backlight can encompass a pixel array within the curved surface to effectively provide illumination to the curved display plane. The invention will be further described below by way of various embodiments.

Figure 10 illustrates an embodiment of a flat panel display. The backlight liquid crystal display 100 according to an embodiment of the present invention includes a liquid crystal display module 112, a flat light source as the backlight module 114, and a plurality of optical films interposed between the liquid crystal module 112 and the backlight module 114. The liquid crystal module 112 includes liquid crystal sandwiched between two transparent substrates, and a control circuit for defining a two-dimensional pixel array. The backlight module 114 provides a flat light distribution. Whether it is a backlit type light source, the light source extends in a plane or an edge-lit type light source. As shown in FIG. 10, a line light source 116 is provided. At the edge of the light guide plate 118. The reflective sheet 120 is used to direct light from the line source 116 through the edge of the light guide plate 118 to enter the light guide plate 118. The light guide plate has a structure (for example, a tapered plate and a light reflecting and/or light scattering surface defined on a bottom surface facing the liquid crystal module 112) for distributing and guiding light through the facing liquid crystal module The top surface of 112. The optical film may include optical upper and lower diffusers 122 and 124 for diffusing light from the surface of the flat surface of the light guide plate 118. It is to be noted that, based on the optical diffusion characteristics of the optical substrate of the present invention as described below, although FIG. 10 shows two diffusion sheets, in one embodiment, at least the upper diffusion sheet 122 is unnecessary. The lower diffusion sheet 124 can also be omitted. This can reduce the overall thickness of the liquid crystal display 100. It should be noted that the diffusion sheet or layer is different from the optical substrate (i.e., the brightness or illumination enhancement sheet described below) in which the diffusion sheet does not have a prismatic structure. The diffuser scatters and distributes light rather than directing light to enhance illumination. The optical substrate of the present invention has a prismatic structure designed to diffuse light and enhance illumination.

In particular, the optical film shown in FIG. 6a further comprises an optical substrate relating to one or more structured surfaces of the present invention, which can diffuse light and redistribute the traversed light, so that the light distribution of the emitted film can be Guided to travel along the normal to the diaphragm. In the illustrated embodiment, it has two structured optical substrates 126 and 128 (which may have similar structures) in relation to the present invention, arranged with a longitudinal prismatic structure that is perpendicular to the two substrates. The structures of the optical substrates 126 and 128 are used to diffuse light and enhance illumination brightness, redirecting light out of the display. The light entering the liquid crystal module 112 after passing through the combined optical film is evenly distributed in the plane of the liquid crystal module 112 in the space, and has a relatively strong normal light intensity. The structured optical substrates 126 and 128 reduce the need for individual diffusers between the liquid crystal module 112 and the upper structural substrate 126. Furthermore, the structural optical substrates 126 and 128 associated with the present invention can reduce interference patterns generated between the substrates and between the liquid crystal module and the upper substrate. Optionally, corresponding to the present invention, only one of the optical substrates 126 and 128 needs to have a structure (e.g., only the lower optical substrate 128) to provide an acceptable level of interference and optical diffusion.

The optical substrate relating to the present invention can be used for a liquid crystal display screen such as a television, a notebook computer, a screen, a handheld device such as a mobile phone, a digital camera, a personal digital assistant or the like to make the display brighter.

When the backlight module 114 is displayed as a light source 116 disposed at the edge of the light guide plate 118, the backlight module can be set for another light source, such as an array of LEDs located at the edge of the light guide plate, or a planar LED array on the light guide plate. Without departing from the spirit and scope of the invention.

FIG. 6a illustrates a structural view of an optical substrate 50, which may be used in the structured optical substrate 126 and/or 128 of FIG. 10, in accordance with an embodiment of the present invention. The optical substrate 50 has a light incident surface 52 and a light exit surface 54 having a prismatic structure, which may be a parallel array 56 of a plurality of longitudinal prisms 58 extending transversely. The longitudinal prism 58 is curved laterally in a smooth curve. In another embodiment (not shown), the curved section (that is, the section curved in a particular direction, or a curved section having a C-shape) is coupled to each other at both ends to form a unitary body Curved longitudinal prismatic structure. In the illustrated embodiment, the light incident surface 52 is unstructured but smooth and flat and/or smooth. It is to be understood that the light incident surface 52 can be textured (eg, frost or matte finish or particles dispersed on the surface; see U.S. Patent Application Serial No. 12/832,021, filed on Jul. 7, 2010, the It is fully quoted as the disclosure of this specification). In the illustrated embodiment, in the overall optical substrate structure, the light exit surface and the structured light incident surface are substantially parallel to each other (that is, a substrate structure that is not tapered as a whole is formed, such as a backlight module). Light guide plate, either convex or concave)

In the embodiment of Fig. 6a, the transverse curved columns 56 of the longitudinal prisms 58 are arranged to be laterally parallel (side by side) and define parallel wave fronts 60 and troughs 62. A wavy facet is defined between each adjacent wave front 60 and trough 62. In the embodiment illustrated in Figure 6a, the lateral undulations are regular, have a fixed wavelength and/or amplitude (i.e., the extent of lateral deformation), and generally have a sinusoidal shape. The lateral undulations may have other waveforms, which may be irregular and/or random wavelengths and/or amplitudes (or lateral deformations) (see the embodiment of Figure 9). The angle of the apex of the wave front may be a right angle, and the wave fronts on the entire substrate plane have the same or similar height and/or the troughs have the same or similar depth. Each prism 58 has a fixed segment shape in the x-z plane. In other embodiments, the lateral waveforms may be irregular and have more variable wavelengths and amplitudes.

To simplify the reference, the following xyz vertical coordinates will be used to explain the various directions. As shown in Figure 6a, the x-axis is the direction across the wave front and trough, also known as the lateral or span direction. The y-axis is perpendicular to the x-axis and generally follows the direction of the long sides of the prism 58. The direction of the long side of the prism can be used as an approximate direction in which the wave front 60 advances from one end of the prism 58 to the other end, and the prisms are curved along the y-axis direction. The light incident surface 52 is located in the x-y plane. For a square optical substrate, the x-axis and the y-axis can be along two sides perpendicular to each other on the substrate. The z-axis is perpendicular to the x-axis and the y-axis. The edge of one end of the curved row 56 showing the lateral arrangement of the prismatic blocks 58 is located in the x-z plane, as shown in Figure 6a, which also represents a cross-sectional view in the x-z plane. The reference frame of the section of the prism 58 is a section on the x-z plane at different points on the y-axis. Further, the reference frame in the horizontal direction is the x-y plane, and the reference frame in the vertical direction is the z direction.

In the illustrated embodiment, substrate 50 includes two separate layers, with a top structured surface layer 68 having a structured light exit surface 54 and a bottom base layer 66 having a flat light incident surface 52. The two layers are adhered together to form the substrate 50. It will be appreciated that the substrate may be constructed of a single integrated physical material layer rather than two separate physical layers without departing from the scope and spirit of the invention. The optical substrate 50 can be a single or monolithic structure comprising a prismatic structure with the base integrated into the surface defining the structure.

In the illustrated embodiment, the structural surface layer 68 and the base layer 66 are constructed of different materials. The structured surface layer 68 can be constructed of an optically transparent material, preferably a polymeric resin such as an ultraviolet or visible radiation photohardenable resin. In general, the structural surface 54 is coated with a coating composition having a resinizable bridging resin on the main mold or the main tympanic chamber and undergoes a hardening process. The base layer 66 may be made of PET (polyethylene terephthalate) material, but may be made of the same transparent material as the structural layer 68. The substrate layer 66 provides the necessary thickness for structural integrity to complete the fabrication of the optical illumination enhancement sheet.

The dimensions of the surface of the structure are generally as follows, for example: Thickness of the base layer = height of tens of microns to several centimeters of peaks (measured from the top of the base layer) = tens to hundreds of microns from the top of the base layer to the bottom of the trough Spacing = apex angle of about 0.5 to several hundred micron peaks = about 70 to 110 degrees spacing of adjacent peaks = tens to hundreds of micrometers Wavelength of transverse wavy prisms W = tens of microns to several centimeters Lateral deformation D (that is, twice the amplitude of the transverse wavy prism) = several to several hundred microns

In another embodiment, the structured light exit surface of the optical substrate further has a wavy prismatic structure on the surface of the structure that varies in peak height, which is additional to the transversely wavy prismatic structure (see figure 13, also seen in Figure 7a). The peak height can be changed in a sequential, semi-sequential or random and quasi-random manner. Figure 7a shows the regularity of the peaks and the sequential changes, along with a common sine wave.

In another embodiment, the structured light exit surface further comprises a predetermined structural irregular portion on the surface of the structure, with or without a varying peak height. This preset irregularity may be equivalent to a structurally undesired structural defect in the process, such as a non-faceted flat portion of the prismatic structure in the surface of the structure (eg, on a peak or trough) (see Figure 9 and Figure 13). Also seen in Figure 8a). Structural irregularities are distributed across the light exit surface of the structure, using at least one of sequential, semi-sequential or random and quasi-random. The predetermined irregularities introduced into the light exiting surface can cause some user-perceptible defects caused by defects in the structure, and such structural defects are unintentionally included in the structural light exiting surface during the process. The pre-defined structurally irregular defect masking effect can be further referred to in U.S. Patent Application Serial No. 11/825,139, filed on Jan. 2, 2007, the entire disclosure of which is hereby incorporated by reference. Computer simulation of optical diffusion effects:

The computer simulation model was used as a motion analysis of the optical diffusion effect, comprising only two interlaced brightness enhancement optical substrates in accordance with the present invention. In general, for the purpose of the motion analysis, only one of the substrates has a wavy prismatic structure, a varying prism peak height or a flat irregular shape, which will be fully described below. Only one of the two substrates has a structure, and the effect of the structured surface is easier to determine. The upper substrate has a linear triangular prism structure on one side and a bright or smooth surface on the other side. The underlying substrate is structured using only one of a corrugated prism, a prism peak height, or a flat irregularity. The underlying structural surface is adjacent to the shiny side of the upper substrate and the other side of the lower substrate is bright or smooth. The light source is input from a smooth light incident surface of the substrate. The simulation model is thus simplified and used to obtain the optical diffusion profile of the light emitted from the upper substrate. Light reflectors, light guides, and other components are not specifically considered here.

A computer simulation was used to investigate the light diffusion effect along the xz plane and the yz plane of the substrate 50, which has varying degrees of wavy structure (i.e., varying degrees of lateral deformation D) and the same wavelength W = 100 μm. . The simulation is performed on a combination of an upper optical substrate 70 (see FIG. 12) and a lower optical substrate having a substrate 50 having a vertically aligned, uniform array of regular prisms 71, wherein the upper substrate 70 and the lower substrate 50 is rotated 90 degrees about the z-axis such that the x-axis of the upper substrate 70 is aligned with the y-axis of the lower substrate 50. The lower substrate 70 facing the structural surface of the lower substrate 50 is smooth toward the lower side. The upper substrate 70 has a peak of a highest point of 50 μm and an apex angle of 90 degrees. The lower substrate has similar peak peaks and apex angles. Lambertian light is directed to the light incident surface at the bottom of the lower substrate. The optical diffusion effect of the diaphragm architecture can be more easily achieved by structuring only one of the two optical substrates into a transversely wavy prismatic structure (or varying peak heights and flat irregularities in other simulations).

Figures 6b to 6f respectively represent some simulation results corresponding to the lower substrate 50 having wavy prisms having a wavelength of W = 100 μm and deformations of D = 0, 20, 30, 40 μm. The left side of Figures 6b to 6f represents the optical diffusion effect produced along the x-z plane of the substrate, and the substrate 50 has a prismatic structure having the features of the present invention as shown in Figure 6a. The right side of Figures 6b to 6f represents the optical diffusion effect produced along the y-z plane of the substrate, and the substrate 50 has a prismatic structure having the features of the present invention as shown in Figure 6a. Based on the simulation results, the trend of the optical diffusion effect can be clearly seen by a general person, in which the diffusion of the light emitted from the upper substrate 70 has a significant change in the uniformity of the high deformation D. These simulation results show that as the reverse deformation D is higher, the diffused light from the exit surface rapidly increases in the x direction and the y direction. Compared to the direction of the long side (y-z plane), the emitted light is diffused more in the lateral or transverse direction (x-z plane). With a deformation of 0 (as in Figure 6b), the emitted light can be more concentrated and significantly less diffuse.

In order to achieve the purpose of the dynamics analysis simulating the effect of varying the peak height, FIG. 7a shows a schematic view of the optical substrate 72 with only varying peak heights along each elongated prismatic structure. The peak height of the prismatic structure changes with the variable V.

The computer simulation was used to investigate optical diffusion effects along the x-y plane and the y-z plane on an optical substrate 72 having varying degrees of peak height variable V. As described in the previous embodiment, the simulated process consists of an upper optical substrate 70 (see FIG. 12) having straight, uniform and regular prisms 71 of lateral columns, and a lower optical substrate having the structure of the optical substrate 72. The upper optical substrate 70 and the lower optical substrate 72 are rotated about the z-axis such that the x-axis of the upper substrate 70 can be aligned with the y-axis of the lower substrate 72. The remaining simulated conditions are similar to the simulated conditions of Figures 6b through 6f previously. The lower side of the upper substrate 70 facing the lower surface of the lower substrate 72 is smooth. The upper substrate 70 has a peak apex of 50 μm and an apex angle of 90 degrees. The lower substrate 72 has similar peak apex and apex angles. The Lambertian light system is directed to the light incident surface at the bottom of the lower substrate.

Figures 7b to 7f represent simulation results of the lower substrate 72 of V = 0, 10, 20, 30, 40 μm having peak height variables, respectively. The left side of Figures 7b to 7f represents the optical diffusion effect along the x-z plane of the lower substrate 72, the substrate of which has a prismatic structure of the features of the invention as shown in Figure 7a. The right side of Figures 7b to 7f represents the optical diffusion effect along the y-z plane of the lower substrate 72. It can be seen from the results of the simulation that the optical diffusion effect does not change greatly with the increase of the peak height variable V, wherein the uniformity of the diffused outgoing light distribution from the upper substrate 70 is only slightly increased, at a higher peak height variable V. The simulation results show that with the increased peak height variable V, the diffused light along the x and y axes does not change significantly from the exit surface. The output light is still concentrated and less diffuses as the peak height variable V changes.

However, in order to achieve a flat irregular simulated motion analysis, FIG. 8a illustrates an optical substrate 76 having only a predetermined irregularity 78 distributed in the prismatic structure of the substrate. To simplify the simulation model, the structure is repositioned into a straight regular prismatic prism 84 with flat grooves 82 between adjacent prisms 84. The ratio R of b to a (as shown in Fig. 8b) is used to control the percentage of the total area of the flat irregularities. Figures 8c to 8g show the trend of optical diffusion effects for structures with ratios R = 0, 2.5, 5, 10 and 20%.

Computer simulations were used to investigate the optical diffusion effects along the x-z plane and the y-z plane on optical substrates 80 having varying degrees of ratio R. As described in the previous embodiment, the simulation is carried out in the following combinations: an upper optical substrate 70 having a straight uniform and regular prism 71 lateral array (as shown in FIG. 12) and a lower substrate having a structure of the optical substrate 80, wherein the upper substrate 70 and The lower substrate 80 is rotated 90 degrees around the z-axis such that the x-axis of the upper substrate 70 is aligned with the y-axis of the lower substrate 80. The remaining simulation conditions are similar to the previous simulations of Figures 6b through 6f. The lower side of the upper substrate 70 facing the structural surface of the lower substrate 50 is smooth. The upper substrate 70 has a peak height of 50 μm and an apex angle of 90 degrees. The lower substrate 80 has similar peak heights and apex angles. The Lambertian light system is directed to the light incident surface at the bottom of the lower substrate.

Figures 8c to 8g represent simulation results for the lower optical substrate 80 having ratios R = 0, 2.5, 5, 10, respectively. The left side of Figures 8c to 8g represents the optical diffusion effect of the lower substrate 80 along the y-z plane, which has the prismatic structure of the features of the present invention, as shown in Figure 8b. The right side of Figures 8c to 8g represents the optical diffusion effect of the lower substrate 80 along the y-z plane. From these simulation results, it is understood that the optical diffusion effect does not change greatly with increasing R, in which the diffused emitted light from the upper substrate 70 is distributed with little change in uniformity. The simulation results show that with the increasing R, the diffused rays from the exit surface do not change significantly along the x and y directions. Although the ratio R changes, the concentration of the output light and the less diffuseness remain at the same level.

Based on the previously described wavy prism structure, peak height variation, and flat irregularity, etc., using different modes of motion analysis, the following optical diffusion effects can be observed, each of which is considered separately. When the lateral deformation D of the wavy prism structure is gradually increased, the overall diffused light from the light exiting surface of the upper substrate is rapidly increased. When the peak height variation V is gradually increased, the overall diffused light from the exit surface of the upper substrate is slightly increased. Accordingly, the lateral deformation D of the wavy prism produces more significant effects on the diffused light. The flattened irregularity ratio R has the least effect compared to the lateral deformation and the peak height variation. According to previous diffusion analysis, it is expected that the effect of combining different methods can reduce interference ripple without sacrificing diffusion.

The previously described simulation does not consider randomly or regularly arranging different degrees of lateral deformation D, a combination of peak height variable V and flat rule ratio R. All simulated structures are parallel to the prism. It is expected that if the lateral deformation D, the peak height variable V, and the flat regular ratio R are used at appropriate positions and heights, the diffusion effect can be enhanced. Experimental results:

The prototype of the optical substrate according to the present invention is made to include a combination of lateral prism deformation, peak height variation, and irregularity, which is calculated and properly distributed at various positions and heights. Figure 9a is a SEM photograph showing wavy prisms and flat irregularities of different sizes. Figure 9b is an enlarged view of Figure 9a. Figure 13 is a perspective view of an optical substrate 77 having lateral wavy prisms (as in Figure 6a), prism peak height variations (section 79, as shown in Figure 7a), and flat irregularities 78 (as shown in Figure 8a). Show).

When interfering corrugations are observed, an upper optical reinforcing substrate having a smooth surface on one side and an irregular surface having no smooth wave prism deformation, peak height variation or flatness is implemented. The upper straight prismatic substrate is stacked above the prototype of the present invention. Each of the lower substrate prototypes according to the present invention, like the computer simulation arrangement, is stacked alternately with the upper straight prism substrate. The stacked substrates are illuminated by a backlight as shown in FIG. Interference corrugations (light and dark staggered lines) can be observed above the light exit surface of the upper straight prism substrate.

Table 1 shows the performance of nine embodiments of the lower substrate prototype. The degree of interference ripple is referred to the interference ripple (scaled from 0 to 5) divided into levels 5, in a reference example of an enhancement diaphragm with two interleaved straight prisms. The gain is the ratio of the brightness of an embodiment thereof to the light guide of this embodiment.

Examples 4 and 8 reduced the rating from 5 to 1 and 1.5. Interference ripples are eliminated in other embodiments. Compared to the 25 μm deformation in the absence of irregularities in Example 8, Example 4 shows that a deformation of 12 μm mixed with a flat irregularity of 10.4% can produce a significant improvement and better performance of the interference ripple. This shows that irregularities are useful for eliminating diffused light from the ripples. However, Embodiments 1 to 4 show that the larger the area of the flat irregular shape, the lower the gain. In order to maintain the gain, the flat irregularities should be intentionally arranged and the range of irregularities should be controlled for different needs in different applications. In general, the effect of flat irregularities on interfering corrugations depends on the total area, number, shape, size, and flat irregularity of the flat irregularities.

Table 1 <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> </td><td> wavy horizontal </td><td> prismatic deformation </td><td> peak height variation</td><td> flat irregularity</td><td> interference ripple</td><td> </td></tr><tr><td > Examples </td><td> Average (μm) </td><td> Maximum (μm) </td><td> (μm) </td><td> (%) </td>< Td> degree</td><td> gain</td></tr><tr><td> 1 </td><td> 25 </td><td> 55 </td><td> < 10 </td><td> 2.1 </td><td> 0 </td><td> 1.55 </td></tr><tr><td> 2 </td><td> 24 </ Td><td> 48 </td><td> <10 </td><td> 4.3 </td><td> 0 </td><td> 1.51 </td></tr><tr> <td> 3 </td><td> 26 </td><td> 39 </td><td> <10 </td><td> 8.3 </td><td> 0 </td>< Td> 1.46 </td></tr><tr><td> 4 </td><td> 12 </td><td> 21 </td><td> <10 </td><td> 10.4 </td><td> 1 </td><td> 1.46 </td></tr><tr><td> 5 </td><td> 29 </td><td> 54 </ Td><td> <10 </td><td> 1.1 </td><td> 0 </td><td> 1.54 </td></tr><tr><td> 6 </td> <td> 28 </td><td> 53 </td><td> <10 </td><td> 2.5 </td><td> 0 </td><td> 1.54 </td>< /tr><tr> <td> 7 </td><td> 30 </td><td> 55 </td><td> <10 </td><td> 0.1 </td><td> 0 </td>< Td> 1.54 </td></tr><tr><td> 8 </td><td> 25 </td><td> 38 </td><td> <10 </td><td> 0 </td><td> 1.5 </td><td> 1.55 </td></tr><tr><td> 9 </td><td> 28 </td><td> 45 </ Td><td> <5 </td><td> 0 </td><td> 0 </td><td> 1.54 </td></tr></TBODY></TABLE>

In order to provide an acceptable degree of interference ripple reduction, a combination of lateral waveform variation, peak height variation, and irregularity ratio is not necessary. For example, an optical substrate may only contain lateral deformation without peak height variation and irregularities. As shown in Example 9, a lateral deformation of 28 μm and a slight peak height variation can also eliminate interference ripples. In addition, even if the peak height variation is reduced to zero, if some flat irregularities still exist, there is still an effect of eliminating interference ripples.

The structured surface of the object of the present invention can be produced in accordance with the number of process techniques, including a micromachining process using a mold made of a hard tool for the manufacture of the above-described irregular prismatic profile. The hardware tool can be a very small diamond tool that is mounted on a computer numerically controlled machine (for example, turning, milling, and cutting/shaping machines). Preferably, these machines may incorporate vibration or disturbance generators to assist in the movement of the tool for small offsets and to assist in the production of irregular prisms of varying degrees. The conventional Slow Tool Servo (STS), Fast Tool Servo (FTS), and ultrasonic vibration machines are examples that can be implemented. For example, U.S. Patent No. 6,581,286 discloses one of the applications of FTS, which is used to make grooves on an optical film by means of thread cutting. The tool is mounted on the machine to create a constant peak angle in the x-z plane in the y-direction of the prism. The above surface of the optical substrate can be obtained by using the above machine to form a surface in the mold to increase more degrees of freedom.

The master can be used to mold the optical element directly or to electrically form another replicated master that is used to mold the optical element. The mold can be in the form of a belt, a drum, a disk or a groove. The mold can be used to form a crucible structure on the substrate by hot engraving and/or by adding ultraviolet drying or thermal expansion material to the structure. The mold can also be used to form an optical component by injection molding. The substrate or coating material can be an organic, inorganic or a mixture of optically transparent materials, and can comprise suspension diffusion, birefringence or reflection adjusting particles.

For a further discussion of the process of forming a substrate having a structured surface, reference is made to U.S. Patent No. 7,618,164, the entire disclosure of which is incorporated herein by reference.

According to the invention, the optical substrate (i.e., 50, 72, 80, 77) comprises prismatic posts, structured light exiting surfaces having elongated prisms that are laterally curved, pre-defined, intentionally created irregularities, and/ Or a combination of prismatic wavefront variations, the combination of which enhances brightness, reduces ripple interference, and masks the user's deficiencies. An LCD having an optical substrate of the features of the present invention can be used in an electronic device. As shown in FIG. 11, an electronic device 110 (which may be a PDA, a cell phone, a television, a display screen, a portable computer, a refrigerator, etc.) includes an LCD 100 in accordance with an embodiment of the present invention. The LCD 100 includes the optical substrate of the above features of the present invention. The electronic device 110 can be further included in a suitable housing, such as a user input interface such as a button and a button (shown schematically as block 116), and the image data control electronic circuit, such as a management image data stream controller that is passed to the LCD 100 ( Illustrated in block 112, an electronic circuit designed for electronic device 110, which may include a processor, analog to digital converter, memory device, data storage device, etc. (shown collectively as indicated by block 118), and a power supply Such as a power supply, a battery, or a socket for connecting an external power source (shown schematically as block 114), and the like are well-known techniques.

It will be appreciated by those skilled in the art that various modifications and changes can be made in the structure and the process disclosed in the present invention without departing from the scope and spirit of the invention. The present invention is intended to cover modifications and variations of the present invention, which are within the scope of the appended claims.

50‧‧‧Optical substrate
52‧‧‧Light incident surface
54‧‧‧Light shot surface
56‧‧‧Parallel columns
58‧‧‧ longitudinal prism
60‧‧‧Crest
62‧‧‧Valley
66‧‧‧ grassroots
68‧‧‧Structural surface layer
70‧‧‧Upper optical substrate
71‧‧‧ prism
72‧‧‧lower optical substrate
76‧‧‧Optical substrate
77‧‧‧Optical substrate
78‧‧‧ irregular
Section 79‧‧‧
80‧‧‧Optical substrate
82‧‧‧ trench
84‧‧‧ prism
100‧‧‧LCD display
110‧‧‧Electronic devices
112‧‧‧LCD module
114‧‧‧Backlight module
116‧‧‧Line light source
118‧‧‧Light guide
120‧‧‧reflector
122‧‧‧Upper diffusion film
124‧‧‧Diffuser
126‧‧‧Optical substrate
128‧‧‧Optical substrate
V‧‧‧ peak height variable
W‧‧‧wavelength of transverse wavy prism
D‧‧‧Transverse deformation

To fully understand the nature and advantages of the invention, and the preferred embodiments, reference should be In the following figures, like reference numerals are used for similar or similar elements. 1 is a schematic diagram showing the architecture of a prior art LCD; FIGS. 2A-2C illustrate prior art optical substrates having different surface structures; and FIGS. 3 to 5B illustrate a prior art hybrid brightness-enhanced optical substrate; Figure 6a is a perspective view of an optical substrate having a structured surface in the present invention; Figures 6b-6f represent optical diffusion effect simulations along two orthogonal vertical planes of the two substrates, with varying degrees of lateral amplitude. Figure 7a is a perspective view of a structured surface having different peak heights in the present invention; Figures 7b-7f represent optical diffusion effect simulations along two orthogonal vertical planes of two substrates, the two substrates having different heights. Figure 8a is a schematic perspective view of a structured surface having a predetermined irregular distribution of the present invention; Figure 8b is a perspective view of a structured surface having a predetermined irregular distribution in another embodiment of the present invention; Figure 8c-8g Representing the optical diffusion effect simulation along two orthogonal vertical planes of the two substrates, the two substrates have a predetermined irregular distribution thereon. 9A-9b are SEM images of an optical substrate prototype having a corrugated prism and a predetermined irregular distribution; FIG. 10 is a view showing an LCD structure having an optical substrate according to an embodiment of the present invention; An electronic device of an LCD panel comprising an optical substrate according to an embodiment of the present invention; FIG. 12 is a perspective view of an optical substrate having a uniform prismatic lateral array; and FIG. 13 is an optical substrate according to an embodiment of the present invention. An optical substrate having a structured surface combined with structural features.

50‧‧‧Optical substrate

52‧‧‧Light incident surface

54‧‧‧Light shot surface

56‧‧‧Parallel columns

58‧‧‧ longitudinal prism

60‧‧‧Crest

62‧‧‧Valley

66‧‧‧ grassroots

68‧‧‧Structural surface layer

Claims (10)

a light directing film comprising a light input surface, a structured light output surface relative to the light input surface, and a reference plane between the light input surface and the structured light output surface, the reference plane being perpendicular to a thickness direction of the light guiding film, wherein the structured light output surface comprises a plurality of curved microstructures, wherein a cross-sectional view of the curved microstructures defines a plurality of valleys, the valleys including a first valley and a second valley And a distance from the first valley to the reference plane is different from a distance from the second valley to the reference plane. The light guiding film of claim 1, wherein each of the curved microstructures is a turn. a light directing film comprising a light input surface, a structured light output surface relative to the light input surface, and a reference plane between the light input surface and the structured light output surface, the reference plane being perpendicular to a thickness direction of the light directing film, wherein the structured light output surface comprises a plurality of curved microstructures, wherein a cross-sectional view of the curved microstructures defines a plurality of valleys, wherein each valley has a distance from the reference plane The distances vary with different locations of the valleys on the structured light output surface. The light guiding film of claim 3, wherein each of the curved microstructures is a turn. a light guiding film comprising: a substrate having a first surface; and a plurality of curved microstructures disposed over the first surface of the substrate; wherein a cross-sectional view of the curved microstructures defines a plurality of valleys, The valleys include a first valley and a second valley, wherein the distance of the first valley to the first surface is different from the distance of the second valley to the first surface. The light guiding film of claim 5, wherein each of the curved microstructures is a turn. The light guiding film of claim 5, wherein the curved microstructures are arranged in a first order in a width direction thereof. a light directing film comprising: a substrate having a first surface; and a plurality of curved microstructures disposed over the first surface of the substrate; wherein a cross-sectional view of the curved microstructures defines a plurality of valleys, wherein Each of the valleys has a distance from the first surface, the distances varying with different locations of the valleys on the surface of the curved microstructures. The light guiding film of claim 8, wherein each of the curved microstructures is one turn. The light guiding film of claim 8, wherein the curved microstructures are arranged in a first order in a width direction thereof.