KR20080109732A - Optical display with fluted optical plate - Google Patents

Abstract

A display system has a light source, a display panel and an arrangement of light management layers disposed between the light source and the display panel. The light source illuminates the display panel through the arrangement of light management layers. The arrangement of light management layers includes a fluted plate that has a front layer facing the display panel, a back layer facing the light source, and a plurality of connecting members connecting the front and back layers. In some embodiments the fluted plate includes a first light management layer, a cross member substantially parallel to, and spaced apart from, the first light management layer, and an arrangement of first connecting members connecting the cross member and the first light management layer. ® KIPO & WIPO 2009

Description

Optical display with grooved optical plate {OPTICAL DISPLAY WITH FLUTED OPTICAL PLATE}

TECHNICAL FIELD The present invention relates to optical displays, and more particularly to a display system that is illuminated from behind as can be used in LCD monitors and LCD televisions.

Liquid crystal displays (LCDs) are optical displays used in devices such as laptop computers, hand-held calculators, digital clocks, and televisions. Some LCDs include a light source located on the side of the display, where a light guide is positioned to guide light from the light source to the back of the LCD panel. Other LCDs, such as some LCD monitors and LCD televisions (LCD-TVs), are directly illuminated using a number of light sources located behind the LCD panel. This arrangement is becoming more and more common in large displays because the optical power requirement to achieve a certain level of display brightness increases with the square of the display size, while the area available for positioning the light source along the sides of the display. This only increases linearly with the display size. In addition, some LCD applications, such as LCD-TVs, require that the display be bright enough to be viewed from a greater distance than other applications, and the viewing angle requirement for LCD-TVs is generally LCD monitors and hands. It is different from the requirements of the held device.

Some LCD monitors and most LCD-TVs are usually illuminated from behind by a number of cold cathode fluorescent lamps (CCFLs). These light sources are linear and extend across the entire width of the display, with the result that the back of the display is illuminated by a series of bright stripes separated by darker areas. Such an illumination profile is not desirable, so a diffuser plate is used to smooth the illumination profile at the back of the LCD device.

Currently, in LCD-TV diffusers, randomization of polymethyl methacrylate (PMMA), poly (carbonate), cycloolefin, polymethylmethacrylate in combination with various dispersed phases including glass, polystyrene beads and CaCO ₃ particles Polymer matrices of copolymer or polystyrene are used. These plates often deform or warp after exposure of the lamp to elevated temperatures. In addition, some diffuser plates are equipped with diffuse characteristics that vary spatially across their width in an attempt to make the illumination profile at the back of the LCD panel more uniform. Such nonuniform diffusers are sometimes called printed pattern diffusers. They are expensive to manufacture and increase manufacturing cost since the diffusion pattern must be aligned with the illumination source during assembly. In addition, the diffuser plate requires customized extrusion compounding to evenly distribute the diffuser particles throughout the polymer matrix, which also adds cost.

Moreover, to prevent warping or other types of physical distortion, the diffuser plate should be of minimum thickness for its height and width. As the size of the display increases, this means that the diffuser plate also becomes thicker and thus the weight of the display increases.

One embodiment of the present invention relates to a display system having a light source, a display panel, and an arrangement of a light management layer disposed between the light source and the display panel. The light source illuminates the display panel through an array of light management layers. The arrangement of the light management layer includes a fluted plate having a front layer facing the display panel, a back layer facing the light source, and a plurality of connecting members connecting the front layer and the back layer.

Another embodiment of the invention is directed to a light management unit comprising a grooved layer. The grooved layer includes a first light management layer, a cross member that is substantially parallel to the first light management layer and spaced apart from the first light management layer, and connects the horizontal member to the first light management layer. It has an arrangement of a first connecting member.

These and other aspects of the present application will be apparent from the detailed description below. In no event, however, should the above summary be construed as limiting the claimed technical subject matter, which should be limited only by the appended claims, which may be amended during the procedure.

The invention may be more fully understood in view of the following detailed description of various embodiments of the invention in conjunction with the accompanying drawings in which like reference numerals indicate like elements.

1 shows schematically a display device using a grooved plate;

2A is a schematic illustration of a grooved plate;

2B and 2C schematically show a grooved plate with an optical film attached thereto.

3 schematically illustrates a grooved plate having a spatially variable single pass transmission.

4 schematically illustrates a grooved plate having a spatially variable refractive index.

5A and 5B schematically show grooved plates with upper and lower layers each having a spatially varying thickness.

6A and 6B schematically illustrate grooved plates with upper and lower layers each having a spatially varying thickness;

7A, 7B and 7C schematically show grooved plates with grooves of different cross-sectional shapes.

8A is a schematic plan view of a grooved plate showing grooves arranged in parallel.

8B is a schematic plan view of a grooved plate showing a set of parallel grooves arranged vertically;

9 and 10 schematically illustrate grooved plates with optically useful surface structures.

11A, 11B, 12A, and 12B schematically illustrate various optical film arrangements including grooved plates.

13A and 13B schematically show the construction of a grooved plate using spine attached to an optical film.

14A and 14B schematically show the configuration of a grooved plate using double-sided spines attached to an optical film.

15 and 16 schematically illustrate different film arrangements formed around a double sided spine.

FIG. 17 schematically shows the construction of a grooved plate using a first layer and a second layer with interconnecting members; and FIG.

18 schematically illustrates a display system in which a heat transfer medium flows through a groove of a grooved plate.

While the present invention may follow various modifications and alternative forms, specific forms thereof will be illustrated and described in detail by way of example. However, it should be understood that there is no intention to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

The invention is applicable to liquid crystal displays (LCD or LC displays) and to LCDs used in LCDs and edge type LCDs, such as LCD monitors and LCD televisions (LCD-TVs), which are directly illuminated from behind.

Diffusion plates currently used in LCD-TVs are based on polymer matrices formed as rigid sheets, such as polymethyl methacrylate (PMMA), polycarbonate (PC) or cyclo-olefins. The sheet comprises diffused particles, for example organic particles, inorganic particles or voids (bubbles). These plates often deform or warp after being exposed to the elevated temperature of the light source used to illuminate the display. These plates are also more expensive to manufacture and assemble the final display device.

The present application discloses a direct illuminated LCD device having an array of light management layers located between the LCD panel itself and the light source. The arrangement of the light management layer can include a diffusion layer whose transmission and haze levels are designed to provide a direct LC display whose luminance is relatively uniform across the display.

A schematic exploded view of an exemplary direct LC display device 100 is shown in FIG. 1. Such a display device 100 may be used for an LCD monitor or an LCD-TV, for example. Display device 100 is based on the use of LC panel 102 which typically includes an LC layer 104 disposed between panel plates 106. The plate 106 is often formed of glass and may include an alignment layer and an electrode structure on its inner surface for controlling the orientation of the liquid crystal in the LC layer 104. The electrode structures are typically arranged to define the area of the LC panel pixels, ie the LC layer, in which the orientation of the liquid crystal can be controlled independently of the adjacent area. In addition, color filters may be provided with one or more plates 106 to impart color to the displayed image.

The upper absorbing polarizer 108 is located on the LC layer 104, and the lower absorbing polarizer 110 is located below the LC layer 104. In the illustrated embodiment, the upper and lower absorbing polarizers are located outside of the LC panel 102. The absorbing polarizers 108, 110 and the LC panel 102 are combined to control the light transmission from the backlight 112 through the display 100 to the viewer. In some LC displays, the absorbing polarizers 108 and 110 may be arranged with their transmission axes perpendicular. When a pixel of the LC layer 104 is not activated, that pixel may not change the polarization of light passing through it. Thus, when the absorbing polarizers 108 and 110 are vertically aligned, the light passing through the lower absorbing polarizer 110 is absorbed by the upper absorbing polarizer 108. On the other hand, when the pixel is activated, the polarization of the light passing through rotates so that at least some of the light passing through the lower absorbing polarizer 110 also passes through the upper absorbing polarizer 108. When the different pixels of the LC layer 104 are selectively activated, for example by the controller 114, the light exits the display at some desired location and forms an image that the viewer sees. The controller may include, for example, a computer or television controller that receives and displays television images. Optional one or more layers 109 may be provided over the upper absorbing polarizer 108, for example to provide mechanical and / or environmental protection for the display surface. In one exemplary embodiment, layer 109 may include a hardcoat over absorbing polarizer 108.

It will be appreciated that some types of LC displays may operate in a different manner than described above. For example, the absorbing polarizers can be aligned in parallel and the LC panel can rotate the polarization of the light when in an inactive state. Regardless, the basic structure of such displays remains similar to that described above.

The backlight 112 includes a plurality of light sources 116 that generate light to illuminate the LC panel 102. A linear cold cathode fluorescent tube extending across the display device 100 is commonly used as the light source 116 in the display device 100. However, other types of light sources may be used, such as filament or arc lamps, light emitting diodes (LEDs), lasers, flat fluorescent panels or external fluorescent lamps. This enumeration of light sources is not intended to be exhaustive or exhaustive, but merely illustrative.

The backlight 112 may also include a reflector 118 that reflects light traveling downward from the light source 116, ie away from the LC panel 102. Reflector 118 may also be useful for reproducing light within display device 100 as described below. The reflector 118 may be a specular reflector or may be a diffuse reflector. One example of a specular reflector that can be used as the reflector 118 is Vikuiti ™ Enhanced Specular Reflection (ESR) film available from 3M Company, St. Paul, Minn., USA. Examples of suitable diffuse reflectors include polymers such as polyethylene terephthalate (PET), polycarbonate (PC), polypropylene, polystyrene, etc., into which diffuse reflecting particles such as titanium dioxide, barium sulfate, calcium carbonate and the like have been introduced. Other examples of diffuse reflectors including microporous materials and fibril containing materials are discussed in US Pat. No. 6,780,355 (Kretman et al.).

An array of light management layers 120 is located between the backlight 112 and the LC panel 102. The light management layer affects light traveling from the backlight 112 to improve the operation of the display apparatus 100. For example, the array 120 of light management layers can include a diffusion layer 122. The diffusion layer 122 is used to diffuse the light received from the light source to increase the uniformity of the illumination light incident on the LC panel 102. As a result, this allows the viewer to perceive brighter images more uniformly. Diffusion layer 122 may include bulk diffusion particles distributed throughout the layer, or may include one or more surface diffusion structures, or a combination thereof.

In addition, the arrangement of the light management layer 120 may include a gain diffuser, which is a layer that diffuses light generally in the viewing direction. In some embodiments, the gain diffuser includes transparent particles that protrude from the surface of the film, thus providing optical power to the light passing through the particles. This reduces the divergence of the light, leading to an increase in on-axis brightness, often called gain. Some types of gain diffusers are described in more detail in US Pat. No. 6,572,961 (Koyama et al.).

The array of light management layers 120 may also include a reflective polarizer 124. The light source 116 typically generates unpolarized light, but the bottom absorbing polarizer 110 only transmits one polarization state, so that approximately half of the light generated by the light source 116 is the LC layer 104. ) Does not penetrate. However, reflective polarizer 124 may be used to reflect light that would otherwise have been absorbed by the bottom absorbing polarizer, so that light can be reproduced by reflection between reflective polarizer 124 and reflector 118. At least a portion of the light reflected by the reflective polarizer 124 returns to the reflective polarizer 124 in a polarization state that is transmitted through the reflective polarizer 124 and the lower absorption polarizer 110 to the LC layer 104 after the polarization is removed. I can go. In this manner, the reflective polarizer 124 may be used to increase the fraction of light emitted by the light source 116 and reaching the LC layer 104, so that the image produced by the display device 100 is Is brighter.

Any suitable type of reflective polarizer, such as a multilayer optical film (MOF) reflective polarizer; Diffusely reflective polarizing film (DRPF) such as continuous / disperse phase polarizers, wire grid reflective polarizers or cholesteric reflective polarizers can be used.

Both MOF and continuous / disperse phase reflective polarizers rely on the difference in refractive index between at least two materials, which are typically polymeric materials, to selectively reflect light in one polarization state while transmitting light in an orthogonal polarization state. . Some examples of MOF reflective polarizers are described in co-owned US Pat. No. 5,882,774 (Jonza et al.). Commercially available examples of MOF reflective polarizers include Viquity DBEF-D200 and DBEF-D440 multilayer reflective polarizers, including diffusing surfaces available from 3M Company, St. Paul, Minn.

Examples of suitable DRPFs include continuous / disperse phase reflective polarizers as described in co-owned U.S. Patent No. 5,825,543 (Ouderkirk et al.) And, for example, co-owned U.S. Patent No. 5,867,316 (Carlson) Carlson et al.). Another suitable type of DRPF is described in US Pat. No. 5,751,388 (Larson).

Some examples of suitable wire grid polarizers include those described in US Pat. No. 6,122,103 (Perkins et al.). Wire grid polarizers are particularly available from Moxtek Inc., Orem, Utah, USA.

Some examples of suitable cholesteric polarizers include, for example, those described in US Pat. No. 5,793,456 (Broer et al.) And US Pat. No. 6,917,399 (Pekorny et al.). A cholesteric polarizer is often provided with a quarter wave retarding layer on the output side such that light passing through the cholesteric polarizer is converted to linear polarized light.

The array of light management layers 120 may also include a brightness enhancement layer 128. The brightness enhancement layer is a layer that includes a surface structure that redirects off-axis light in a direction closer to the axis of the display. This increases the amount of light propagating on-axis through the LC layer 104, thus increasing the brightness of the image as seen by the viewer. One example is a prismatic luminance enhancement layer having a plurality of prismatic ridges that redirect illumination light through refraction and reflection. Examples of prismatic brightness enhancing layers that can be used in display devices are Viquity, a prismatic film available from 3M Company, St. Paul, Minn., Including BEFII 90/24, BEFII 90/50, BEFIIIM 90/50, and BEFIIIT. BEFII and BEFIII families.

The array 120 of light management layers can also include a support layer 130, which can be used to provide support for other light management layers. In some arrangements, one of the other light management layers may be integrally formed with the support layer 130. For example, some existing televisions include diffusing particles in a relatively thick (2-3 mm) rigid polymer sheet, thus combining the function of providing support and light diffusing properties in a single layer.

The support layer 130 advantageously comprises a grooved plate, which is a plate comprising a groove or space between two surfaces of the plate. A cross-sectional view of an exemplary grooved plate 200 is shown schematically in FIG. 2A. The grooved plate 200 includes a first layer 202 and a second layer 204, with a connecting member 206 connecting the first layer 202 and the second layer 204. The open space 208 surrounded by the connecting member 206 and the first and second layers 202, 204 can be considered a groove.

The grooved plate 200 is self-supporting and may be used to provide support for other light management layers in some exemplary embodiments. The grooved plate 200 may be made of any suitable material, for example an organic material such as a polymer. For example, grooved plate 200 may be formed using any suitable method, such as extrusion and molding.

The thickness of the grooved plate 200 and the size of the grooves 208 can be selected according to the particular application. For example, the grooved plate may range in thickness from a few millimeters, for example approximately 1 mm to 4 mm, or may be thicker. The grooved plate 200 may also be thinner, for example about 50 μm or more in thickness. In addition, the spacing between the centers of the grooves 208 can be selected to be any suitable value. For example, the spacing can range from about 1 to 4 mm or more. In other embodiments, the groove spacing may be smaller, for example reduced to about 50 μm or less.

The use of grooved plates can reduce the weight of display systems such as televisions. For example, in a 10 inch cm (40 inch) LCD-TV, a conventional solid diffuser plate is typically about 1 kg (2.3 lbs) in weight and accounts for about 5% of the total weight of the television. The grooved plate has a weight of only a portion of the comparable solid plate, usually about 25%, so that the grooved plate can provide only about 1% of the total weight of the television.

In addition, the grooved plate has the mechanical advantage of an "I-beam" in which the upper and lower plates are separated by the air space and the connecting member. Thus, grooved plates provide high resistance to warping and curling under high lighting conditions typical of many display systems.

The direction of the grooves can be oriented in the desired direction with respect to the light source. For example, if the light source is long as in most fluorescent lamps, the grooves may be oriented parallel to the light source or not to be parallel. The particular orientation between the light source and the grooves in a given design of the light source and the grooved plate may provide improved illumination uniformity and also improved thermal response, for example improved warping, curling, and the like.

Suitable polymeric materials for the grooved plate may be amorphous or semicrystalline and may include homopolymers, copolymers or blends thereof. Polymer foams may also be used. Examples of polymeric materials include amorphous polymers such as poly (carbonate) (PC); Poly (styrene) (PS); Acrylates such as acrylic sheets supplied under the ACRYLITE® brand by Cy Industries, Inc., Rockaway, NJ; Acrylic copolymers such as isooctyl acrylate / acrylic acid; Poly (methylmethacrylate) (PMMA); PMMA copolymer; Cycloolefins; Cycloolefin copolymers; Acrylonitrile butadiene styrene (ABS); Styrene acrylonitrile copolymers (SAN); Epoxy; Poly (vinylcyclohexane); PMMA / poly (vinylfluoride) blends; Atactic poly (propylene); Poly (phenylene oxide) alloys; Styrenic block copolymers; Polyimide; Polysulfones; Poly (vinyl chloride); Poly (dimethyl siloxane) (PDMS); Polyurethane; Poly (carbonate) / aliphatic PET blends; Semicrystalline polymers such as poly (ethylene) (PE); Poly (propylene) (PP); Olefin copolymers such as PP / PE copolymers; Poly (ethylene terephthalate) (PET); Poly (ethylene naphthalate) (PEN); Polyamides; Ionomers; Vinyl acetate / polyethylene copolymers; Cellulose acetate; Cellulose acetate butyrate; Fluoropolymers; Poly (styrene) -poly (ethylene) copolymers; PET and PEN copolymers; And blends comprising one or more of the polymers listed above.

Some exemplary embodiments of the grooved plate 200 include a polymeric material that is substantially transparent to light. Some other exemplary embodiments may include a diffusion material in the grooved plate 200 using, for example, a polymer matrix comprising diffusion particles. The polymer matrix can be any suitable type of polymer that is substantially transparent to visible light, such as any of the polymeric materials listed above.

The diffusing particles may be any type of particles useful for diffusing light, for example transparent particles, diffusing reflecting particles whose refractive index is different from the surrounding polymer matrix, or voids or bubbles in the matrix. Examples of suitable transparent particles include solid or hollow inorganic particles, for example glass beads or glass shells, solid or hollow polymer particles, for example solid polymer spheres or polymer hollow shells. Examples of suitable diffusely reflective particles include particles or beads such as PS, PMMA, polysiloxane, titanium dioxide (TiO ₂ ), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ), magnesium sulfate (MgSO ₄ ), and the like. In addition, voids in the polymer matrix can be used to diffuse light. Such voids may be filled with a gas, for example air or carbon dioxide.

Other additives may be provided in the grooved plate. For example, the grooved plate may include an antioxidant such as Irganox 1010 available from Ciba Specialty Chemicals, Tarrytown, NY. Other examples of additives include one or more of anti-weathering agents, UV absorbers, disturbing amine light stabilizers, dispersants, lubricants, antistatic agents, pigments or dyes, nucleating agents, flame retardants and blowing agents or nanoparticles. This may be included.

All of the grooved plate 200 may be formed of a diffusion material, or selected portions of the grooved plate 200 may be made of the diffusion material. For example, the first layer 202 or the second layer 204 may be formed of a diffusion material and the remainder of the plate 200 is formed of some other material. In other embodiments, both the first and second layers 202, 204 may be formed of a diffusion material. When a grooved plate 200 formed of a diffusion material is used in the display system as illustrated in FIG. 1, the grooved plate not only provides mechanical support but also provides a diffusion function, so that a separate diffusion layer can be omitted. Can be.

In another exemplary embodiment, the grooved plate 200 may be provided with a diffusion layer 210, as shown schematically in FIG. 2B, for example. The diffusion layer 210 may be attached to the first layer 202 or the second layer 204. In addition, in some embodiments, a diffusion layer may be attached to each of the first and second layers 202, 204. The diffusion layer 210 may be attached to the grooved plate 200 using an adhesive layer (not shown), or in other embodiments the diffusion layer 210 may adhere to the grooved plate 200 itself. Adhesive layer.

Commercially available materials suitable for use as the diffusion layer include 3M ™ Scotchcal ™ Diffuser Films, types 3635-70 and 3635-30 available from 3M Company, St. Paul, Minn. 3M ScotchCal ElectroCut ™ Graphic Film, type 7725-314. Other commercially available diffusers include acrylic foam tapes such as 3M VHB ™ Acrylic Foam Tape No. 4920.

In some exemplary embodiments, the diffusion layer 210 has a uniform diffusion characteristic across its width, that is, the amount of diffusion experienced by light is the same for the points across the width of the diffusion layer 210.

Diffusion layer 210 may be supplemented or replaced with an optionally patterned or optional patterned diffuser 210a. Optional patterned diffuser 210a may include a patterned diffusion surface, such as, for example, titanium dioxide (TiO ₂ ) particles, or a printed layer of diffuser. The patterned diffuser 210a may be placed on the diffuser layer 210 between the diffuser layer 210 and the grooved plate 200. In addition, the patterned diffuser can be attached to the grooved plate 200 formed at least in part from a diffusing material.

The grooved plate 200 may be protected from UV light, for example, by including an ultraviolet (UV) absorbing material or a material resistant to the effects of UV light. Cyasorb ™ UV-1164, available from Cytec Technology Corporation, Wilmington, Delaware, USA, and Tinuvin ™, available from Ciba Specialty Chemicals, Tarrytown, NY, USA. Suitable UV absorbing compounds, including 1577, are commercially available. The grooved plate 200 may also include a brightness enhancing phosphor that converts UV light into visible light.

Other materials may be included in the layer of the grooved plate 200 to reduce the adverse effects of UV light. One example of such a material is an impaired amine light stabilizing composition (HALS). In general, the most useful HALS are those derived from tetramethyl piperidine and those that can be considered as polymerizable tertiary amines. Suitable HALS compositions are commercially available under the trade designation “Tinuvin” from Ciba Specialty Chemicals Corporation, Tarrytown, NY, for example. One such useful HALS composition is Tinuvin 622. UV absorbing materials and HALS are further described in US Pat. No. 6,613,819 (Johnson et al.).

In another embodiment, the grooved plate 200 may have two diffusion layers 210, 212 attached to the first and second layers 202, 204 of the grooved plate 200, respectively. Diffusion layers 210 and 212 may be attached directly to each layer 202 and 204 of grooved plate 200 as shown in FIG. 2C, respectively, or using a layer of adhesive (not shown). Can be attached.

The two diffusion layers 210, 212 may have the same diffusion characteristics or may have different diffusion characteristics. For example, the diffusion layer 210 may have a different transmission or haze level than the second diffusion layer 212 or may be of a different thickness.

The optical properties of the grooved plate may be uniform across its width, but this is not necessary. In some exemplary embodiments, for example the grooved plate 300 shown in FIG. 3, the amount of diffusion imparted by the grooved plate 300 itself is spatially across the width of the plate 300. Can be changed to This can be achieved, for example, by introducing bulk diffuse particles unevenly across extruded grooved plates. The graph on the grooved plate shows the spatial variation of single pass transmittance (T). Single pass transmission is the proportion of incident light that passes through the grooved plate 300, with higher levels of transmission indicating less diffusion and lower levels of transmission indicating more diffusion. In the illustrated example, the periodicity of the spatial change in transmittance is equal to the separation distance between the connecting members 306. This spatial change in diffusion can be useful to reduce the non-uniformity of the brightness of the transmitted light due to the connecting member 306. However, the change in T does not have to have this periodicity, and the change in T may or may not have any other periodicity.

Another optical feature of the grooved plate that can vary across the grooved plate 400 is the refractive index of one or both of the first and second layers 402, 404, as schematically shown in FIG. 4. to be. Such a change can be achieved, for example, by unevenly introducing materials of different refractive index across the extruded grooved plate. The graph on the grooved plate 400 shows the spatial change in refractive index. In the illustrated example, the periodicity of the spatial variation of the refractive index is equal to the separation distance between the connecting members 406. This spatial change in diffusion can be useful to reduce the non-uniformity of the brightness of the transmitted light due to the connecting member 406. However, the change in the refractive index does not have to have such periodicity, and the change in the refractive index may or may not have any other periodicity.

In some demonstrative embodiments, one or more of the layers of the grooved plate may have a thickness that varies across the plate. For example, in the grooved plate 500 shown schematically in FIG. 5A, the thickness of the first layer 502 is relatively thin at the center of the plate 500 from being relatively thin at the edge of the plate 500. Varying to thick, the second layer 504 maintains a constant thickness across its width. Changes in the thickness of the first layer 502 can be used, in particular, to provide additional strength to the plate or to change the optical characteristics of the plate. In the illustrated example, where the first layer 502 includes bulk diffusing particles of uniform concentration, a change in the thickness of the first layer 502 can be used to provide a spatially varying diffusion feature. In the illustrated example, the diffusion of light through the central portion of the plate 500 is greater than at the edges.

In other embodiments, the second layer 504, or both the first layer 502 and the second layer 504, may have a variable thickness. For example, as shown in FIG. 5B, the grooved plate 520 has a first layer 522 of constant thickness and a second layer 524 of variable thickness. It will be appreciated that changes in the thickness of the first layer 502, 522 and / or the second layer 504, 524 may be periodic or aperiodic.

In some embodiments, the surface of the material surrounding the space or groove may be parallel or perpendicular to the outer surface of the grooved plate, but this is not a requirement. In some demonstrative embodiments, the surface of the first or second layer forming the grooves may not be parallel to the top surface of the grooved plate. This is due to one particular grooved plate 600 where the lower surface 602a of the first layer 602 is not parallel to the upper surface 604a of the second layer 604 for at least a portion of the groove 608. Is schematically shown in FIG. 6A. Thus, the cross-sectional shape of some grooves 608a is not square or rectangular.

The bottom surface of the groove may also not be parallel to the bottom surface of the second layer. For example, in the embodiment of FIG. 6B, the thickness of both the first and second layers 622, 624 is not constant over the width of the plate 620. In another exemplary embodiment, the first layer can be a constant thickness, only the second plate has a non- constant thickness.

The grooves do not have to be quadrilateral in shape and may take other shapes. For example, in one exemplary embodiment shown schematically in FIG. 7A, the grooved plate 700 is a triangular connecting member 706 connecting between the first layer 702 and the second layer 704. Has Thus, the groove 708 also has a triangular cross section. In another exemplary embodiment, shown schematically in FIG. 7B, the grooved plate 720 has upper and lower layers 722, 724 having sinusoidal shaped inner surfaces 722a, 724a forming a groove 728. Has The connecting member 726 is formed where the sinusoidal surfaces coincide.

In another exemplary embodiment, shown schematically in FIG. 7C, the grooved plate 730 has upper and lower layers 732, 734 connected together through a curved connecting member 736. In the illustrated embodiment, the curved connecting member 736 alternately bends in one direction and curved in the opposite direction to produce a corrugated effect.

In addition to those illustrated herein, many different cross sections can be used for the connecting member and the groove. In addition, the illustrated embodiments are presented for illustrative purposes only and are not intended to limit the scope of the present invention to only those cross sections illustrated herein.

In some exemplary embodiments, for example the grooved plate 800 shown schematically in FIG. 8A showing a top view of the plate 800, the grooves 808 are linear and arranged parallel to each other. In another exemplary embodiment, for example, the grooved plate 820 schematically illustrated in FIG. 8B, the grooves 828 are linear but perpendicular to the first group but parallel to each other with the first group of grooves parallel to each other. It is arranged to have a second group of grooves 828. In other embodiments, different grooves may be placed at different angles from each other.

In some embodiments, the surface of the first or second layer may be flat and have an antireflective coating. In other embodiments, the first and / or second layer may provide some optical functionality. For example, the outer or inner surface of the first and / or second layer can have a matte finish. In other exemplary embodiments, the first and second layers may have some surface structure. For example, the grooved plate 900 shown schematically in FIG. 9 has first and second layers 902, 904 attached together through a connecting member 906. In this particular embodiment, the top surface 910 of the first layer 902 has a series of prismatic ribs 912. Ribs 912 may lie parallel to each other, in which case surface 910 acts as a prismatic luminance enhancing layer, redirecting some off-axis light exemplified by rays 914. It proceeds in a direction more parallel to the axis 916.

Grooved plates may have other types of surfaces. In another example, shown schematically in FIG. 10, the first layer 1002 of the grooved plate 1000 includes an upper portion comprising a series of lenses 1012 that provide optical power to light 1014 passing through the plate. Has a surface 1010. Lens 1012 has the same width as the spacing between connecting members 1006 but is not required. The lens 1012 may be a lenticular lens that extends across the width of the plate 1000. Lenses of this type are particularly well suited to plates made using extrusion processes. Other methods, such as molding, may be used to form the lens 1012.

The grooved plate can be used to support other optical layers in the display. For example, one or more other layers may be attached to the grooved plate. The examples below are presented to illustrate some possible combinations of grooved plates and other layers. 11A shows an arrangement 1100 of an optical layer having a grooved plate 1101 with a reflective polarizing layer 1110 attached to the top surface of the top layer 1102. The reflective polarizing layer 1110 may be attached using an adhesive, for example a transparent adhesive or a light diffusing adhesive. The prism type luminance enhancement layer 1112 may be attached on the reflective polarization layer 1110. In some demonstrative embodiments, it may be desirable for at least some of the light to enter the brightness enhancement layer 1112 through an air interface or an interface that progresses from a low refractive index to a high refractive index. Thus, a layer of low refractive index material, such as a fluorinated polymer, may be positioned between the brightness enhancing layer 1112 and the subsequent layer below the brightness enhancing layer 1112.

In another exemplary embodiment, an air gap may be provided between the brightness enhancement layer 1112 and the layer underneath the brightness enhancement layer 1112. One approach to providing an air gap is to include a structure on one or both of the brightness enhancing layer 1112 and opposing faces of the layer underneath the brightness enhancing layer 1112. In the illustrated embodiment, the bottom surface 1114 of the brightness enhancement layer 1112 is configured to have a protrusion 1116 in contact with an adjacent layer. Thus, voids 1118 are formed between the protrusions 1116, so that light entering the luminance enhancement layer 1112 at locations between the protrusions 1116 enters through the air interface. In another embodiment, the reflective polarization layer 1110 may be omitted and the prismatic luminance enhancement layer 1112 may be directly attached to the grooved plate 1101. In some embodiments, the grooved layer 1101 may provide light diffusion or separate diffusion layers may be provided, for example (i) grooved layers and (ii) reflective polarizing layers 1110. And / or to the lower layer 1104 of the grooved layer 1101 or between the prismatic luminance enhancement layer 1112 or the first layer 1102 of the grooved layer 1101. .

Other approaches may be used to form voids to provide an air interface to light entering the brightness enhancement layer. For example, the brightness enhancing layer can have a flat bottom surface, and adjacent layers are structured to have protrusions. These and additional approaches are discussed in US Pat. No. 7,010,212 (Emmons et al.). Any one of the grooved plates discussed herein can be configured to provide an air interface to light entering the brightness enhancement layer.

The order of the films attached to the grooved plate 1101 may be different. For example, a reflective polarization layer 1110 may be attached to the prismatic surface of the brightness enhancement layer 1112, and the brightness enhancement layer 1112 is attached to the grooved plate 1101. This arrangement 1120 is schematically illustrated in FIG. 11B. The attachment of the optical film to the prismatic surface of the brightness enhancement layer is further described in US Pat. No. 6,846,089 (Stevenson et al.).

An exemplary embodiment is illustrated schematically in FIG. 12A illustrating an arrangement 1200 in which one or more films are attached to the bottom layer of the grooved plate. In this embodiment, a reflective polarizer 1210 is attached to the second layer 1204 of the grooved plate 1201, and a prismatic luminance enhancement layer 1212 is attached to the first layer of the grooved plate 1201. Attached. An optional diffusion layer 1214 may be attached to the bottom surface of reflective polarizer 1210. In other embodiments, the grooved plate itself may provide some diffusion. In such cases, it may be desirable for the grooved plate 1201 to not considerably polarize light passing through the reflective polarizer 1210.

Another exemplary embodiment 1220 of a grooved plate 1201 attached to an array of light management films is schematically illustrated in FIG. 12B. In this embodiment 1220, the diffusion layer 1222 is attached to the grooved plate 1201. The intermediate layer 1224 is disposed on the diffusion layer 1222, and the prismatic luminance enhancing layer 1226 is disposed above the intermediate layer 1224. Diffusion layer 1222 can be, for example, acrylic foam tape, which is deformed when intermediate layer 1224 is pressed into foam tape, creating a recessed area where the intermediate layer seats. Interlayer 1224 may have an optical function, for example, interlayer 1224 may be a reflective polarizer film. Examples of other suitable arrangements of light management films that can be used with grooved plates are described in more detail in US Patent Application Publication 2006/0082699 (Gehlsen et al.).

In addition to molding, there are other ways to make grooved plates. One method is to attach a spine with a pre-attached connecting member to another optical film. This approach is shown schematically in FIGS. 13A and 13B. Spine 1302 has an array of transverse members 1304 and connecting members 1306. The connecting member 1306 may be formed integrally with the horizontal member 1304. For example, spine 1302 can be formed by molding or extrusion. Spine 1302 may be formed of the same type of material as described above for the grooved plate. Thus, spine 1302 may be formed of an optically transparent or light scattering material.

The optical film 1310 is attached to the connecting member 1306. The optical film can be any suitable type of film. For example, the film 1310 may be a prismatic luminance enhancing film, a diffusing film, a reflective polarizing film, a gain diffuser film, a lens film, an absorbing polarizer, a matte film, or the like. In addition, the optical film 1310 may simply be a transparent film. Moreover, the optical film may also be attached to the spine 1302 under the transverse member 1304.

13B shows an optical film 1310 attached to the connecting member 1306. The film 1310 may be attached to the connecting member using any suitable method. For example, the lower surface 1312 of the film 1310 and / or the tip 1314 of the connecting member 1306 may be glued using an adhesive, which adhesive may be attached to the lower surface 1312 and the connecting member tip 1314. ) Is placed in contact and then cured. In another approach where both the film 1310 and the connecting member 1306 are formed of a polymerizable material, the film 1310 and the connecting member 1306 are placed in contact before each polymerizable material is fully crosslinked. Film 1310 and connecting member 1306 are then crosslinked together. For example, several other approaches can be used, which immediately contact the optical film to the molten polymer to form a bond between the optical film and the groove immediately after extrusion. In another approach, the grooves can be heated (after extrusion) and then laminated. Coextruded grooves may also be employed whereby the grooves are formed of one material, such as a matrix (non-adhesive structural member) in which other materials are coextruded onto the tip (adhesive material).

After the film 1310 is attached, the film 1310 and the spine 1302 together form a plate with grooves 1316.

In another embodiment schematically illustrated in FIGS. 14A (with the elements separated) and 14B (with the elements attached together), the spine 1402 is connected to each side of the transverse member 1404 with a connecting member 1406a, 1406b). Two optical films 1410a and 1410b may be attached to each set of connecting members 1406a and 1406b. Optical films 1406a and 1406b can be any desired type of optical film, such as transparent films, diffuser films, prismatic brightness enhancing films, reflective polarizing films, and the like.

After at least one of the films 1410a, 1410b is attached to the spine 1402, the films 1410a, 1410b and the spine 1402 together form a plate with grooves 1416.

One particular embodiment of an array 1500 of optical films that includes a spine 1502 of the type shown in FIG. 14B is schematically illustrated in FIG. 15. In this embodiment, the diffusion layer 1510 is attached to the lower connecting member 1506b and the prismatic luminance enhancing layer 1512 is attached to the upper connecting member. Reflective polarization layer 1514 may optionally be attached to the structured side of prismatic brightness enhancement layer 1512.

Another exemplary arrangement 1600 is schematically illustrated in FIG. 16 where a reflective polarizer 1514 is located between the diffusion layer 1510 and the spine 1502.

Another approach to attaching the two layers together is to use interconnectable layers. For example, the two layers may be mechanically attached to each other using an attachment mechanism such as that used to seal a food storage bag. An exemplary embodiment of this mechanism is shown in FIG. 17 showing portions of the top and bottom layers 1702, 1704. Each layer 1702, 1704 has respective interconnecting members 1706, 1708 facing the other layer. When the two layers 1702 and 1704 are pressed together, the interconnecting members 1706 and 1708 are fastened together to form a connecting member. Layers 1702 and 1704 with each interconnect member 1706 and 1708 can be formed using, for example, an extrusion process. Interconnect member 1706 may be the same shape as interconnect member 1708, but is not required.

Regardless of whether the spine is used to connect the top and bottom layers, the grooved plate can be formed in a partially continuous process. The film and optional spine forming the upper and lower layers can be taken out from each roll and attached together. Once the layers are attached to each other, the resulting grooved product is relatively rigid. Individual plates can be cut from continuous grooved products.

Grooved plates can be used to improve thermal management in display systems such as television displays or monitors. An exemplary embodiment of the display system 1800 shown schematically in FIG. 18 includes one or more light sources 1802, grooved plate 1804, an array of light management layers 1806, and display panel 1808. do. Coolant may flow through the grooves of the grooved plate 1804, which leads to lower operating temperatures of the display system. The coolant may be air and in some embodiments air may flow through vertically oriented grooves solely due to natural convection. In another embodiment, the coolant may be forced through the groove by the coolant circulator. For example, fan 1810 may be used to force air through the groove of grooved plate 1804. In another embodiment, a transparent fluid such as water may be forced through the groove by the pump.

It is to be understood that many different possible arrangements are within the scope of the present invention, in which different layers appear in a different order from the bottom up, or in different positions relative to the spine.

The present invention should not be considered limited to the specific embodiments described above, but rather should be understood to cover all aspects of the invention as appropriately set forth in the appended claims. Many modifications, equivalent processes, as well as numerous structures, which may be applied to the present invention upon review of this specification, will be readily apparent to those skilled in the art. For example, freestanding optical films can also be used in display devices with grooved plates to which other optical layers are attached. The display can also use more than one grooved plate. The grooves of the plurality of grooved plates may be arranged parallel to each other, or the grooves of one plate may be oriented so that they are not parallel to the grooves of the plate with the other grooves. To be included.

Claims (19)

Having a display panel side facing towards the display panel and a backlight side facing towards the backlight; An arrangement of the first light management layer, the horizontal member substantially parallel to the first light management layer and spaced apart from the first light management layer, and the first connecting member integral with the horizontal member and attached to the first light management layer. An optical management unit for use between the display panel and the backlight comprising a fluted layer comprising. The light management unit of claim 1, wherein the first light management layer includes one of a diffusion layer, a brightness enhancement layer, and a reflective polarization layer. The light management unit of claim 1, further comprising a second light management layer attached to the grooved layer. The light management unit according to claim 3, wherein the arrangement of the second connection members connects the second light management layer and the transverse member. The light management unit of claim 3, wherein the second light management layer is connected to the first light management layer such that the first light management layer is positioned between the transverse member and the second light management layer. The second connecting member of claim 1, wherein the first connecting member is disposed on the display panel side of the horizontal member and extends from the horizontal member, and is disposed on the backlight side of the horizontal member and extends from the horizontal member. And a second light management layer attached to the connecting member. Light source; Display panel; And An array of light management layers disposed between the light source and the display panel to cause the light source to illuminate the display panel therethrough; The arrangement of the light management layer includes a grooved plate, the grooved plate including a front layer facing the display panel, a back layer facing the light source, and a plurality of connecting members connecting the front layer and the back layer. Display system. The display system of claim 7, wherein the arrangement of the light management layers comprises at least one of a reflective polarizing layer, a diffusing layer, and a prismatic luminance enhancing layer. The display system of claim 7, wherein at least a portion of the grooved plate is formed of a diffusion material. The display system of claim 7, wherein the arrangement of the light management layers further comprises at least one of a diffuser layer, a reflective polarizer layer, and a prismatic luminance enhancement layer. The display system of claim 7, wherein at least one of the front layer and the back layer comprises a first light management layer. The display system of claim 11, wherein the first light management layer comprises at least one of a prismatic brightness enhancement layer, a diffusion layer, and a reflective polarization layer. 12. The connecting member of claim 11 wherein the connecting member comprises first and second connecting members, the first connecting member is attached to the transverse member and connected to the front layer, and the second connecting member is attached to the transverse member and connected to the back layer. And the first light management layer is attached to one of the first connection member and the second connection member, and further comprises a second light management layer connected to the other of the first connection member and the second connection member. . 8. The display system of claim 7, further comprising a controller coupled to control the image displayed by the display panel. The display system of claim 7 wherein the display panel comprises a liquid crystal display (LCD). 8. The display system of claim 7, further comprising a coolant circulator for forcing the cooling medium through the grooves of the grooved plate. The display system of claim 16, wherein the coolant circulator is a fan and the coolant is air. 8. The display system of claim 7, wherein the grooves of the grooved plate are arranged vertically to allow natural convection of air therethrough. 8. A display system according to claim 7, wherein the connecting member comprises a first connecting member attached to the front layer and a second connecting member attached to the back layer, wherein the first connecting member is engaged with the second connecting member.

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