WO2019108696A1

WO2019108696A1 - Light apparatus including a light guide plate

Info

Publication number: WO2019108696A1
Application number: PCT/US2018/062912
Authority: WO
Inventors: Steven Roy Burdette; Raymond Geroe Greene; Dhananjay Joshi; Shenping Li; Krishna Hemanth VEPAKOMMA
Original assignee: Corning Incorporated
Priority date: 2017-11-29
Filing date: 2018-11-28
Publication date: 2019-06-06
Also published as: TW201925882A

Abstract

A light apparatus can comprise a back plate comprising a material comprising a linear coefficient of thermal expansion of from about 30 x 10-7 /°C to about 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. The light apparatus can also comprise a light guide plate comprising a material comprising a linear coefficient of thermal expansion about equal to the linear coefficient of thermal expansion of the back plate. The light apparatus can further comprise a first intermediate layer that can attach the light guide plate to the back plate and at least partially circumscribe a space defined between the back plate and the light guide plate. The first intermediate layer can comprise a Young's Modulus of from about 50 MPa to about 100 GPa.

Description

LIGHT APPARATUS INCLUDING A LIGHT GUIDE PLATE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 62/617,379 filed on January 15, 2018 and U.S. Provisional Application Serial No. 62/592,021 filed on November 29, 2017, the contents of each of which are relied upon and incorporated herein by reference in their entireties.

FIELD

[0002] The present disclosure relates generally to light apparatus and, more particularly, to light apparatus including a light guide plate.

BACKGROUND

[0003] It is known to provide a display apparatus with a polymeric light guide plate that acts as a backlight for the display apparatus. The polymeric light guide plate is typically mounted relative to a frame of the display apparatus.

SUMMARY

[0004] The following presents a simplified summary of the disclosure to provide a basic understanding of some embodiments described in the detailed description.

[0005] In some example embodiments, a light apparatus can comprise a back plate. The back plate can comprise a material comprising a linear coefficient of thermal expansion of from about 30 x 10-7 /°C to about 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. The back plate can further comprise a first major surface, a second major surface, and a thickness defined between the first major surface and the second major surface. The light apparatus can also comprise a light guide plate. The light guide plate can comprise a material comprising a linear coefficient of thermal expansion about equal to the linear coefficient of thermal expansion of the back plate. The light guide plate can also comprise a first major surface, a second major surface, and a thickness defined between the first major surface of the glass light guide plate and the second major surface of the glass light guide plate. The light apparatus can further comprise a first intermediate layer at least partially circumscribing a space defined between the back plate and the light guide plate. The first intermediate layer can attach the light guide plate to the back plate by contacting an outer portion of the first major surface of the light guide plate and the first major surface of the back plate. The first intermediate layer can comprise a Young’s Modulus of from about 50 MPa to about 100 GPa.

[0006] In some embodiments, the first intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

[0007] In some embodiments, the light apparatus can comprise a display panel and a second intermediate layer disposed between the light guide plate and the display panel. The display panel can comprise a thickness defined between a first major surface of display panel and a second major surface of the display panel. The second intermediate layer can attach the display panel to the light guide plate by contacting the first major surface of the display panel and the second major surface of the light guide plate.

[0008] In some embodiments, the first intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

[0009] In some embodiments, the thickness of the display panel can be from about 0.8 mm to about 1.8 mm.

[0010] In some embodiments, the second major surface of the back plate can comprise a first outermost surface of the light apparatus. The second major surface of the display panel can comprise a second outermost surface of the light apparatus. An overall thickness of the light apparatus can be defined between the first outermost surface and the second outermost surface.

[0011] In some embodiments, the overall thickness of the light apparatus can be within a range of from about 2.35 mm to about 13.7 mm.

[0012] In some embodiments, the second intermediate layer can comprise a Young’s Modulus that is less than the Young’s Modulus of the first intermediate layer.

[0013] In some embodiments, the Young’s Modulus of the second intermediate layer can be from about 0.005 MPa to about 0.5 MPa. [0014] In some embodiments, the light apparatus can include a light source optically coupled to an edge of the light guide plate.

[0015] In some embodiments, the light guide plate can comprise a rectangular light guide plate. The first intermediate layer can comprise a first segment extending along a first edge of the rectangular light guide plate, a second segment extending along a second edge of the rectangular light guide plate, and a third segment extending along a third edge of the rectangular light guide plate.

[0016] In some embodiments, the light apparatus can comprise a light source optically coupled to a fourth edge of the rectangular light guide plate.

[0017] In some embodiments, the material of the back plate can comprise a Young’s modulus of from about 10 GPa to about 350 GPa.

[0018] In some embodiments, the material of the back plate can comprise glass.

[0019] In some embodiments, the material of the light guide plate can comprise a Young’s modulus of from about 60 GPa to about 90 GPa.

[0020] In some embodiments, the material of the light guide plate can comprise glass.

[0021] In some embodiments, the back plate can comprise an area that is larger than an area of the light guide plate.

[0022] In some embodiments, the thickness of the back plate can be within a range of from about 0.5 mm to about 5 mm.

[0023] In some embodiments, the thickness of the light guide plate can be within a range of from about 0.5 mm to about 5 mm.

[0024] In some embodiments, the first intermediate layer can comprise a thickness between the first major surface of the light guide plate and the first major surface of the back plate within a range of from about 0.05 mm to about 0.3 mm.

[0025] In some embodiments, the display panel can comprise a liquid crystal display panel.

[0026] In some example embodiments, a light apparatus can comprise a glass back plate comprising a first major surface, a second major surface, and a thickness defined between the first major surface and the second major surface. The light apparatus can comprise a glass light guide plate comprising a first major surface, a second major surface, and a thickness defined between the first major surface of the glass light guide plate and the second major surface of the glass light guide plate. The light apparatus can comprise a first intermediate layer at least partially circumscribing a space defined between the glass back plate and the glass light guide plate. The first intermediate layer can attach the glass light guide plate to the glass back plate by contacting an outer portion of the first major surface of the glass light guide plate and the first major surface of the glass back plate. The first intermediate layer can comprise a Young’s Modulus of from about 50 MPa to about 100 GPa. The light apparatus can further comprise a display panel comprising a thickness defined between a first major surface of the display panel and a second major surface of the display panel. The light apparatus can still further comprise a second intermediate layer. The second intermediate layer can attach the display panel to the light guide plate by contacting the first major surface of the display panel and the second major surface of the light guide plate. The second intermediate layer can comprise a Young’s Modulus that is less than the Young’s Modulus of the first intermediate layer. The light apparatus can further comprise a light source optically coupled to an edge of the glass light guide plate.

[0027] In some embodiments, the first intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

[0028] In some embodiments, the second intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

[0029] In some embodiments, the second major surface of the glass back plate can comprise a first outermost surface of the light apparatus. The second major surface of the display panel can comprise a second outermost surface of the light apparatus. An overall thickness of the light apparatus can be defined between the first outermost surface and the second outermost surface.

[0030] In some embodiments, the display panel can comprise a liquid crystal display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] These and other features, embodiments and advantages are better understood when the following detailed description is read with reference to the accompanying drawings, in which: [0032] FIG. 1 is a front elevational view of an embodiment of a light apparatus in accordance with the disclosure;

[0033] FIG. 2 is a rear elevational view of the light apparatus of FIG. 1;

[0034] FIG. 3 is a sectional view of the light apparatus along line 3-3 of FIG. i;

[0035] FIG. 4 is a sectional view of a left side and a top side of the light apparatus along line 4A-4A of FIG. 2, wherein a sectional view of the right side of the light apparatus along line 4B-4B of FIG. 2 would appear as a mirror image of FIG. 4 about a vertical axis; and

[0036] FIG. 5 is a sectional view of a left side and a top side of a second embodiment of the light apparatus along line 4A-4A of FIG. 2, wherein a sectional view of the right side of the second embodiment of the light apparatus along line 4B- 4B of FIG. 2 would appear as a mirror image of FIG. 5 about the vertical axis.

DETAILED DESCRIPTION

[0037] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0038] FIGS. 1-4 illustrate a light apparatus 101 such as a LED display apparatus, LCD display apparatus or other type of display apparatus. The light apparatus 101 can include a back plate 103. In some embodiments, the back plate 103 can include a material comprising a linear coefficient of thermal expansion of from about 30 x 10-7 /°C to about 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. In further embodiments the linear coefficient of thermal expansion of the back plate 103 can be from 40 x 10-7 /°C to 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. In further embodiments the linear coefficient of thermal expansion of the back plate can be from 70 x 10-7 /°C to 90 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. Providing the back plate 103 with a linear coefficient of thermal expansion within the above-identified ranges can minimize the overall change in dimension of the back plate 103 under temperature fluctuations. In further embodiments, the material of the back plate 103 can comprise a Young’s modulus of from about 10 GPa to about 350 GPa, such as from about 60 GPa to about 150 GPa although other ranges of Young’s modulus may be provided in further embodiments. Providing the back plate 103 with a Young’s modulus from about 10 GPa to about 350 GPa (e.g., from about 60 GPa to about 150 GPa) can help the back plate 103 act as a structural member to help prevent flexing of the light apparatus 101 when supporting the light apparatus 101 and/or handling the light apparatus 101.

[0039] In some embodiments, the material of the back plate 103 can comprise glass although ceramic, composite materials (e.g., glass-ceramic, ceramic-plastic) may be provided in further embodiments. For instance, the back plate 103 can comprise a material (e.g., glass) with a linear coefficient of thermal expansion of from about 30 x 10-7 /°C to about 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C and a Young’s modulus of from about 10 GPa to about 350 GPa. In some embodiments, the back plate 103 may be provided as various glass types that may optionally be finished and/or treated to increase the strength. For instance, in one embodiment, the back plate 103 may comprise soda lime glass that is edge finished and/or thermally tempered to increase the strength of the back plate 103. The back plate 103 may be opaque, translucent or transparent depending on the application. In some embodiments, the back plate 103 can be treated to provide a framed appearance due to a laterally extending portion 414. For instance, treatment can provide the back plate 103 with different colors or textures that reflect, refract, or filter light to provide the framed appearance.

[0040] As shown in FIG. 4, the back plate 103 can include a first major surface 401, a second major surface 403, and a thickness 405 defined between the first major surface 401 and the second major surface 403. As shown, in some embodiments, the first major surface 401 and the second major surface 403 can comprise substantially parallel planar surfaces. Although not shown, the first and second major surface may comprise curved shapes, for example, with the first major surface 401 comprising a concave shape and the second major surface 403 comprising a convex shape. The thickness 405 of the back plate 103 can be minimized to reduce the weight of the light apparatus 101 while still having sufficient thickness to resist deformation under the weight of the light apparatus 101, during handling of the light apparatus 101 and/or under application of other exterior forces to the light apparatus 101. In some embodiments, the average thickness 405 of the back plate 103 can be within a range of from about 0.5 millimeters (mm) to about 5 mm although other thicknesses may be provided in further embodiments. In some embodiments, the average thickness 405 of the back plate 103 can be within a range of from about 1 mm to about 4 mm, such as from about 2 mm to about 3 mm. In further embodiments, the average thickness 405 may be substantially the same throughout at least a portion or substantially the entire area of the back plate 103.

[0041] In some embodiments, the back plate 103 can comprise outer peripheral edges in the shape of a rectangle although other polygonal or curvilinear shapes may be provided in further embodiments. For instance, as shown in FIGS. 1 and 2, the back plate 103 can include a first peripheral edge 105a, a second peripheral edge 105b, and a third peripheral edge 105c. As further shown in FIG. 2, the back plate 103 can include a fourth peripheral edge 105d. The peripheral edges 105a-d are shown in a rectangular shape, wherein the area of the back plate 103 is rectangular. As shown, to form the rectangular shape, the second peripheral edge 105b can be parallel to the fourth peripheral edge 105d and the first peripheral edge 105a can be parallel to the third peripheral edge 105c. As further shown, the second and fourth peripheral edges 105b, 105d can be perpendicular to the first and third peripheral edges 105a, 105c.

[0042] As shown in FIG. 4, the light apparatus 101 can further include a light guide plate 407 that may comprise a wide variety of materials that can transmit light. In some embodiments, the light guide plate 407 can include a material comprising a linear coefficient of thermal expansion about equal to the linear coefficient of thermal expansion of the back plate 103. For instance, the light guide plate 407 can include a linear coefficient of thermal expansion of from about 30 x 10-7 /°C to about 100 x 10- 7 /°C at a temperature within a range of from 0°C to 300°C. In further embodiments the linear coefficient of thermal expansion of the light guide plate 407 can be from 40 x 10-7 /°C to 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. In further embodiments the linear coefficient of thermal expansion of the light guide plate 407 can be from 70 x 10-7 /°C to 90 x 10-7 /°C at a temperature within a range of from 0°C to 300°C. Providing the light guide plate 407 with a linear coefficient of thermal expansion within the above-identified ranges can minimize the overall change in dimension of the light guide plate 407 under temperature fluctuations. Furthermore, providing the light guide plate 407 with a material comprising a thermal coefficient of thermal expansion about equal to the linear coefficient of thermal expansion of the back plate 103 can prevent little if any thermal expansion mismatch between the back plate 103 and the light guide plate 407 during temperature fluctuations. As such, a rigid and fixed connection can be provided between the light guide plate 407 and back plate 103 without thermal fluctuations damaging the very stiff and fixed connection as the light guide plate 407 and back plate 103 would similarly expand and/or contract under temperature differentials. Furthermore, a very stiff and fixed connection between the light guide plate 407 and the back plate 103 can effectively combine the light guide plate 407 and the back plate 103 as a reinforced rigid support member that can greatly increase the structural integrity and stiffness of the light apparatus 101. The combined reinforced rigid support member created by the back plate 103 being fixedly attached to the light guide plate 407 can to help inhibit bending, twisting or other distortions of the light apparatus 101 under any one or combination of its own weight, external forces, and/or internal forces (such as from thermal mismatch of components of the light apparatus).

[0043] In further embodiments, the material of the light guide plate 407 can comprise a Young’s modulus of from about 60 GPa to about 90 GPa, such as from about 60 GPa to about 80 GPa, such as from about 60 GPa to about 70 GPa. Providing the light guide plate 407 with such a Young’s modulus within the above- identified ranges can help the light guide plate 407 act as a structural member to help prevent flexing of the light apparatus 101 when supporting the light apparatus 101 and/or handling the light apparatus 101. In some embodiments, the material of the light guide plate 407 can comprise the same material as the back plate 103. For instance, in some embodiments, light guide plate 407 can comprise glass that can have a linear coefficient of thermal expansion and/or Young’s modulus within the ranges referenced with respect to the light guide plate 407 above. For instance, in one embodiment, the light guide plate 407 can include glass with a linear coefficient of thermal expansion of from about 30 x 10-7 /°C to about 100 x 10-7 /°C at a temperature within a range of from 0°C to 300°C and a Young’s modulus of from about 10 GPa to about 350 GPa.

[0044] If provided, the glass of the light guide plate 407 may be transparent to allow light to pass through the light guide plate 407 to further allow the light guide plate 407 to function as a back light. Thus, in some embodiments, a material of the light guide plate 407 can comprise glass to allow the light guide plate 407 to function as a back light while also allowing the light guide plate 407 to enhance the overall structural integrity and stiffness of the light apparatus 101 by fixedly attaching the light guide plate 407 to the back plate 103. Thus, the light guide plate 407 can function as a back light while also being effectively combined with the back plate 103 as a reinforced rigid support member to help inhibit bending, twisting or other distortions of the light apparatus 101 under any one or combination of its own weight, external forces, and/or internal forces (such as from thermal mismatch of components of the light apparatus).

[0045] As shown in FIG. 4, the light guide plate 407 can include a first major surface 409, a second major surface 411, and a thickness 413 defined between the first major surface 409 and the second major surface 411. As shown, in some embodiments, the first major surface 409 and the second major surface 411 can comprise substantially parallel planar surfaces. Although not shown, the first and second major surface may comprise curved shapes, for example, with the first major surface 409 comprising a convex shape and the second major surface 411 comprising a concave shape. The thickness 413 of the light guide plate 407 can be minimized to reduce the weight of the light apparatus 101 while still having sufficient thickness to resist deformation under the weight of the light apparatus 101, during handling of the light apparatus 101 and/or under application of other exterior forces to the light apparatus 101. In some embodiments, the average thickness 413 of the light guide plate 407 can be within a range of from about 0.5 mm to about 5 mm, such as from about 1 mm to about 4 mm, such as from about 1 mm to about 2 mm, although other thicknesses may be provided in further embodiments. In further embodiments, the average thickness 413 may be substantially the same throughout at least a portion or substantially the entire area of the light guide plate 407.

[0046] In some embodiments, the light guide plate 407 can comprise outer peripheral edges in the shape of a rectangle although other polygonal or curvilinear shapes may be provided in further embodiments. Although not shown, the light guide plate 407 can include a first peripheral edge parallel to the first peripheral edge 105a of the back plate 103, a second peripheral edge parallel to the second peripheral edge 105b of the back plate 103, and a third peripheral edge parallel to the third peripheral edge 105c of the back plate 103. Furthermore, as shown in FIG. 3, the light guide plate 407 can include a fourth peripheral edge 301 parallel to the fourth peripheral edge 105d of the back plate 103. As shown, a light source 303 can be optically coupled to the fourth peripheral edge 301 of the light guide plate 407. In some embodiments, the light source 303 can include an interface 305 designed to optically connect the light source 303 with the fourth peripheral edge 301 of the light guide plate 407 such that light may travel in direction 307 into the fourth peripheral edge 301 wherein the light guide plate 407 functions as a back light for the display panel 107

[0047] As shown, in some embodiments, the peripheral edges of the light guide plate 407 can comprise a rectangular shape that can provide the major surface of the light guide plate 407 with a rectangular area. For instance, as shown in FIGS. 1 and 4, the back plate 103 can include a larger area than the area of the light guide plate 407 such that a portion 414 of the peripheral edges 105a-c can each extend a distance 415 laterally beyond a corresponding peripheral edge 417 of the light guide plate 407. In some embodiments, the distance 415 can be within a range of from about 2 mm to about 8 mm, such as from about 4 mm to about 6 mm although other distances may be provided in further embodiments. In some embodiments, the portion 414 can include a coating 416 (see FIG. 4) such as paint (e.g., black paint) or the portion 414 can be frosted, etched, colored or otherwise treated to provide a framed feature. For instance, if the light apparatus 101 is provided with a display panel 107, the framed feature can provide the light apparatus 101 with the appearance of a picture on glass.

[0048] FIG. 5 illustrates another light apparatus 501 that can have features that are similar or identical to features of the light apparatus 101 discussed throughout this application. Thus, features described with respect to one of the embodiments of FIGS. 4 and 5 can equally apply to the other of the embodiments FIGS. 4 and 5 throughout the disclosure. As such, to simplify discussion, reference to features of one of the embodiments of FIGS. 4 and 5 is understood to apply to the other embodiment of FIGS. 4 and 5. Unlike the embodiment illustrated in FIG. 4, the alternative embodiment shown in FIG. 5 can include the peripheral edges 105a-c that do not laterally extend a distance beyond a corresponding peripheral edge 417 of the light guide plate 407. As shown in FIG. 5, in some embodiments, a cap 504 may be provided to mask peripheral edge areas of the light apparatus 101. In some embodiments, to minimize light loss from the peripheral edge 417 of the light guide plate 407, a reflector with a reflectance from about 0.8 to about 0.99 for visible light may be placed between the cap 504 and the peripheral edge 417 of the light guide plate 407, or in other embodiments an air gap (O.Olmm to 2mm) may be provided between the cap 504 and the peripheral edge 417 of the light guide plate 407.

[0049] The light guide plate 407 and/or the back plate 103 can include a diagonal from 7 cm (centimeters) to 4.3 m (meters) although other sized light guide plates and back plates may incorporate features of the disclosure. For purposes of the disclosure, a diagonal of a plate (e.g., light guide plate 407 or the back plate 103) is considered the dimension extending between opposite comers of the plate (e.g., opposite corners of a rectangular back plate 103 shown in FIG. 2). For instance, with reference to the back plate 103 shown in FIG. 2, the back plate 103 can include a rectangular back plate 103 (including the illustrated rectangular area) with the first and third peripheral edges 105a, 105c defining a width of the back plate 103 and second and fourth peripheral edges 105b, 105d defining a height of the back plate 103. The diagonal of the first and third peripheral edges 105a, 105c shown in FIG. 2 is the dimension extending between the opposite comers of the rectangular the back plate 103 shown in FIG. 2. The diagonal of the rectangular back plate 103 shown in FIG. 2, is also considered the hypotenuse of a right triangle with one of the first and third peripheral edges 105a, 105c and one of the second and fourth peripheral edges 105b, 105d. In some embodiments, throughout the disclosure, the aspect ratio of the width relative to the height of the light guide plate 407 and/or back plate 103 can be from about 1 :1 to about 4:1 although other aspect ratios may be provided in further embodiments.

[0050] As shown in FIG. 4, the light apparatus 101 can include a first intermediate layer 419 that can attach the light guide plate 407 to the back plate 103. In some embodiments, the first intermediate layer 419 can at least partially circumscribe a space 421 defined between the back plate 103 and the light guide plate 407. In some embodiments, the first intermediate layer 419 can include at least one segment, such as one, two, three, four or more segments. For instance, as shown, the first intermediate layer 419 can include three segments 419a-c (see dashed lines in FIG. 1) that may closely follow corresponding peripheral edge segments of the peripheral edge 417 of the light guide plate 407 to partially circumscribe the space 421 to provide access to the space 421. In some embodiments, as shown, the light guide plate 407 can comprise a rectangular light guide plate, wherein the first intermediate layer 419 comprises a first segment 419a extending along a first edge of the rectangular light guide plate 407, a second segment 419b extending along a second edge of the rectangular light guide plate 407, and a third segment 419c extending along a third edge of the rectangular light guide plate 407. Although not shown, in some embodiments, the first intermediate layer 419 may include four segments that closely follow corresponding edge segments of the peripheral edge of the light guide plate to entirely circumscribe the space 421.

[0051] In some embodiments, the first major surface 409 of the light guide plate 407 can include printed ink droplets, can be etched, or otherwise treated to extract light through the first major surface 409 of the light guide plate 407. In some embodiments, a reflective material 423 such as a mirror or reflective foil may be positioned within the space 421 between the light guide plate 407 and the back plate 103. In use, the reflective material 423 can reflect light extracted from the first major surface 409 back into the light guide plate 407 such that the light eventually passes through the second major surface 411 of the light guide plate 407. Although not shown, in some embodiments, the first major surface 401 of the back plate 103 can comprise a highly reflective surface such as a highly polished surface wherein the reflective material 423 may be omitted.

[0052] As shown in FIG. 4, the first intermediate layer 419 can attach the light guide plate 407 to the back plate 103 by contacting an outer portion of the first major surface 409 of the light guide plate 407 and the first major surface 401 of the back plate 103. As shown, in FIG. 5, the first intermediate layer can also attach the light guide plate 407 to the back plate 103 by contacting an outer portion of the first major surface 409 of the light guide plate 407 and an outer portion the first major surface 401 of the back plate 103. The first intermediate layer 419 can comprise a Young’s Modulus of from about 50 MPa to about 100 GPa, such as about 200 MPa to about 50 GPa, such as from about 500 MPa to about 10 GPa. Providing the first intermediate layer 419 with a Young’s Modulus within the above-listed ranges can provide the above-referenced rigid and fixed connection between the light guide plate 407 and the back plate 103. As mentioned above, the rigid and fixed connection can effectively combine the light guide plate 407 and the back plate 103 as a reinforced rigid support structure to greatly enhance the structural integrity and stiffness of the light apparatus 101. Furthermore, the relatively high Young’s Modulus of the first intermediate layer 419 (e.g., from about 50 MPa to about 100 GPa) can be provided without damaging the light guide plate 407, back plate 103 or first intermediate layer 419 under temperature fluctuations in embodiments where the linear coefficient of thermal expansion of the back plate 103 is about equal to the linear coefficient of thermal expansion of the light guide plate 407.

[0053] Referring to FIG. 5, the first intermediate layer 419 can include a thickness 502 between the first major surface 409 of the light guide plate 407 and the first major surface 401 of the back plate 103. In some embodiments, as shown, the thickness 502 can equal the thickness of the space 421. If provided with reflective material 423, the thickness 502 can be within a range of from about 0.1 mm to about 0.5 mm, such as 0.2 mm to 0.4 mm, such as 0.3 mm. However, if the reflective material 423 (e.g., foil layer) is omitted, the thickness 502 may be even smaller. For instance, if reflection is provided by the first major surface 401 of the back plate 103, rather than reflective material positioned within the space 421, the thickness 502 can be greater than 0.05 mm, such as within a range of from about 0.05 mm to about 0.3 mm, such as from about 0.05 mm to about 0.2 mm, such as from about 0.05 mm to about 0.1 mm. Referring to FIG. 4, the first intermediate layer 419 can include a width 425 from about 1 mm to about 5 mm, such as from about 2 mm to about 4 mm such as about 3 mm although other widths may be provided in further embodiments. Providing a reduced width 425 can help reduce interference with a display area while providing a sufficiently high width 425 to increase that bonding area and consequently further rigidify the light apparatus 101.

[0054] In some embodiments, the first intermediate layer 419 can be provided with mechanical and optical properties to enhance the performance of the light apparatus 101. For instance, referring to FIG. 5, the first intermediate layer 419 can include a first adhesive layer 503, a second adhesive layer 505 and an optional spacer layer 507. The first adhesive layer 503, the second adhesive layer 505 and optional spacer layer 507 can be chosen for desired mechanical properties. For instance, the first adhesive layer 503, the second adhesive layer 505, and spacer layer 507 can provide the first intermediate layer 419 with a relatively high Young’s Modulus (e.g., as set forth above of from about 50 MPa to about 100 GPa, such as about 200 MPa to about 50 GPa, such as from about 500 MPa to about 10 GPa). Such relatively high Young’s Modulus of the first intermediate layer 419 can provide a rigid connection between the back plate 103 and the light guide plate 407. In some embodiments, the first adhesive layer 503 and the second adhesive layer 505 can comprise resin (e.g., polyvinyl butyral), epoxy, or other adhesive type.

[0055] In some embodiments, the first intermediate layer 419 can include reflective properties designed to reflect light escaping the light guide plate 407 within the vicinity of the first intermediate layer 419 back into the light guide plate 407 to allow the light guide plate to more efficiently act as a back light for a display area of the light apparatus 101. In some embodiments, the first intermediate layer 419 can include a reflectance from about 0.6 to about 0.99 for visible light, such as from about 0.8 to 0.99, such as from 0.9 to 0.95. For purposes of this application, reflectance is considered total hemispherical reflectance (i.e., diffuse reflection or specular reflection) of white visible light (i.e., light with wavelengths of 390 nanometers (nm) - 700 nm). The reflectance of the intermediate layer 419 can be measured by using the method reported by the article entitled“Optical Reflectance Measurements for Commonly Used Reflectors” published on IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 55, NO. 4, p.2432, AUGUST 2008. In this method, the light source can be a stable un-polarized laser source with a broadband width covering 390- 700nm, a tunable laser with a wavelength tuning range from 390-700nm, or include three lasers emitting at blue (such as, with wavelength ~480nm), green (such as, with wavelength ~550nm), and red (such as, with wavelength ~650nm), respectively. The laser beam is used to shine onto a reflector (such as the intermediate layer 419) at a fixed angle of incidence. The reflected light’s angular distribution is measured by an array of silicon photodiodes. The photodiodes are movable to cover 2p of the solid angle. A computer program controls the motion of the light source and the photodiode array, and the data collection. The incidence angle of the laser beam varies in the range of 0 to 90 degrees, such as 10 to 80 degrees. At each incidence angle of the laser beam, the angular distribution of light reflectance was measured. The reflectance for each incidence at each wavelength can be calculated by integrating the measured angular distribution of light reflectance. Finally, the reflectance of the reflector under the test is achieved by the average for all of these angles and all wavelengths.

[0056] In some embodiments, the outer surface of the spacer layer 507 facing the light guide plate can be designed to provide specular reflectance or diffuse reflectance, but specular reflectance is preferred. For example, the spacer layer 507 can comprise an aluminum foil layer, or a silver foil layer to provide a specular reflective surface that faces the light guide plate 407. In such embodiments, the second adhesive layer 505 can comprise a transparent layer where the first intermediate layer 419 can provide specular reflection of light escaping from the light guide plate 407 off the outer reflective surface of the spacer layer 507, through the transparent second adhesive layer 505 and back into the light guide plate 407. For purposes of this application, an adhesive layer is considered transparent if at least 60% of visible light passes through a 5 millimeter (mm) length of the adhesive layer. Transparent adhesive layers of the disclosure can pass at least 60% for visible light, such as at least 80%, such as at least 90%, such as at least 95% of visible light through a 5 mm length of the adhesive layer. In further embodiments, the outer surface of the spacer layer 507 facing the light guide plate 407 or the spacer 515 itself can comprise a specular reflective film or a diffuser reflective film, but a specular reflective film is preferred. In still further embodiments, the second adhesive layer 505 itself can provide diffuse reflectance. For instance, a pigment particle mixture used in white paint, such as a silica or titanium dioxide (TiCk), can be disbursed in an otherwise transparent second adhesive layer 505 to provide diffuse reflectance of light back to the light guide plate 407.

[0057] In some embodiments, the spacer layer 507, if provided, may operate to isolate the first adhesive layer 503 from the second adhesive layer 505. The spacer layer 507 can also function to increase the Young’s Modulus of the first intermediate layer 419 and/or provide the first intermediate layer 419 with a desired thickness 502. In some embodiments, the spacer can comprise metal (e.g. a metal foil), such as steel, silver, aluminum or other material.

[0058] In some embodiments, even with the rigid connection, the first intermediate layer 419 can be removed for purposes of repair, recycling or the like. Thus, the light guide plate 407 may be removable from the back plate 103. In some embodiments, a hot wire can be used to remove the attachment layer for repairing or reconstructing the light apparatus 101. Any residual portions of the attachment layer attached to the light guide plate 407 and/or back plate 103 can be removed with solvent or other processes.

[0059] In some embodiments, the light apparatus 101 can be provided without a display panel 107. In such embodiments, the light apparatus may operate as a lighting device where light is emitted from the light guide plate 407 to provide a light source. Alternatively, as shown in FIGS. 1 and 3-5, embodiments of the light apparatus 101, 501 can include the display panel 107. In some embodiments, the display panel can include a thickness 426 defined between a first major surface 428 and a second major surface 430 of the display panel 107. In further embodiments, as shown, the thickness 426 of the display panel can be defined between a major surface of a first glass substrate 429 and the second major surface 430 of the display panel 107. Although not necessary, the display panel can be flexed (e.g., from a flat orientation to a bent orientation in some embodiments). In some embodiments, the display panel may be flat although the display panel may have a curved shape or other shape in further embodiments. The thickness 426 can be within a range of from about 0.8 mm to about 1.8 mm, such as from about 1.2 mm to about 1.4 mm although other thicknesses may be provided in further embodiments. In some embodiments, the display panel 107 can be provided as a light emitting diode display panel (LED display panel), a liquid crystal display panel (LCD panel) or other type of display panel. By way of example, the display panel 107 is illustrated as an LCD display panel although other types of display panels may be provided in further embodiments. Referring to FIG. 4, if provided, the LCD panel can optionally include various example components such as an inner polarizer layer 427, the first glass substrate 429, a thin film transistor 431, a liquid crystal 433, a common electrode 435, a RGB color filter 437, a second glass substrate 439 and an outer polarizer layer 441.

[0060] As further shown in FIG. 4, the light apparatus 101 can further include a second intermediate layer 443 that can attach the display panel 107 to the light guide plate 407. In some embodiments, the second intermediate layer 443 can at least partially circumscribe a space 447 defined between the light guide plate 407 and the display panel 107. In some embodiments, the second intermediate layer 443 can include at least one segment, such as one, two, three, four or more segments. In some embodiments, the second intermediate layer 443 can include three segments that can correspond to the three segments 419a-c of the first intermediate layer 419 discussed above. As can be appreciated in FIGS. 4 and 5, in some embodiments, the three segments of the second intermediate layer 443 may be laterally aligned with one another although other relative arrangements may be provided in further embodiments. The three segments of the second intermediate layer 443, if provided, can partially circumscribe the space 447 to provide access to the space 447. Although not shown, in some embodiments, the second intermediate layer 443 may include four segments to entirely circumscribe the space 447. As shown in FIG. 5, optical components, such as a diffuser sheet 509 and a prism sheet 511 may be positioned within the space 447 to prepare light from the light guide plate 407 to be received by the display panel 107.

[0061] The second intermediate layer 443 can include a thickness 513 between the second major surface 411 of the light guide plate 407 and the first major surface 428 of the display panel 107. In some embodiments, as shown, the thickness 513 can equal the thickness of the space 447. To provide sufficient space for the diffuser sheet 509 and the prism sheet 511, the thickness 513 can be within a range of from about 0.5 mm to about 1.6 mm, such as from about 0.8 mm to about 1.5 mm, such as from about 1.2 mm to about 1.4 mm although other thicknesses may be provided in further embodiments.

[0062] The second intermediate layer 443 can be disposed between the light guide plate 407 and the display panel 107. The second intermediate layer 443 can attach the display panel 107 to the light guide plate 407 by contacting a major surface of the first glass substrate 429 of the display panel 107 and the second major surface 411 of the light guide plate 407. The second intermediate layer 443 can include a width 445 that can be similar or identical to the width 425 of the first intermediate layer 419 although the different widths may be provided in further embodiments.

[0063] Due to the various components (e.g., layers) of the display panel 107, the linear coefficient of thermal expansion of the display panel 107 may not match the coefficient of thermal expansion of the light guide plate 407. In some embodiments, the Young’s Modulus of the second intermediate layer 443 may be selected to reduce stress on the display panel 107 and/or the attachment of the display panel 107 with the light guide plate with the second intermediate layer 443. In some embodiments, the second intermediate layer 443 can include a Young’s Modulus that is less than the Young’s Modulus of the first intermediate layer 419. In some embodiments, the Young’s Modulus of the second intermediate layer is from about 0.005 MPa to about 0.5 MPa. Consequently, the Young’s Modulus of the first intermediate layer 419 can be selected relatively higher than the Young’s Modulus of the second intermediate layer to allow a rigid fixed attachment between the back plate 103 and the light guide plate 407 to effectively combine the light guide plate 407 and the back plate 103 as a reinforced rigid support structure to greatly enhance the structural integrity and stiffness of the light apparatus 101. Furthermore, the Young’s Modulus of the second intermediate layer 443 can be selected relatively lower than the Young’s Modulus of the first intermediate layer 419 to provide attachment of the display panel 107 to the light guide plate 407 while accommodating thermal mismatch between the display panel 107 and light guide plate 407 under temperature fluctuations. The display panel 107 can therefore be carried by the reinforced rigid support structure provided by light guide plate 407 and back plate 103 that can be rigidly and fixedly attached to one another.

[0064] In some embodiments, the second intermediate layer 443 can include a spacer layer 515 sandwiched between a first adhesive layer 517 and a second adhesive layer 519. In some embodiments, the spacer layer 515 of the second intermediate layer 443 can be identical to the spacer layer 507 of the first intermediate layer 419. Furthermore, in some embodiments, the first adhesive layer 517 of the second intermediate layer 443 can be identical to the second adhesive layer 505 of the first intermediate layer 419. Still further, the second adhesive layer 519 can comprise a double sided adhesive tape in some embodiments. As such, due to the relatively low Young’s modulus of the second intermediate layer 443, a compliant attachment can be provided between the display panel 107 and the light guide plate 407 to accommodate dimensional differentials developed during temperature fluctuations that may occur due to a mismatch in the linear coefficient of thermal expansion between the glass light guide plate 407 and the display panel 107. As such, stress can be avoided that my cause mechanical failure or mura effect or light leakage due to warping of the display panel 107.

[0065] In some embodiments, the second intermediate layer 443 can include reflective properties designed to reflect light escaping the light guide plate 407 within the vicinity of the second intermediate layer 443 back into the light guide plate 407 to allow the light guide plate to more efficiently act as a back light for a display area of the light apparatus 101. In some embodiments, like the first intermediate layer 419 discussed above, the second intermediate layer 443 can include a reflectance from about 0.6 to about 0.99 for visible lights, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

[0066] In some embodiments, the outer surface of the spacer layer 515 facing the light guide plate can be designed to provide the above-referenced diffuse reflectance or specular reflectance. For example, the spacer layer 515 can comprise an aluminum foil layer, or a silver foil layer to provide a specular reflective surface that faces the light guide plate 407. In such embodiments, the first adhesive layer 517 can comprise a transparent layer where the second intermediate layer 443 can provide specular reflection of light escaping from the light guide plate 407 off the outer reflective surface of the spacer layer 515, through the transparent first adhesive layer 517 and back into the light guide plate 407. In further embodiments, the outer surface of the spacer layer 515 facing the light guide plate 407 or the spacer layer 515 itself can comprise a specular reflective film or diffuser reflective film, but specular reflective film is preferred. In still further embodiments, the first adhesive layer 517 itself can provide diffuse reflectance. For instance, a pigment particle mixture used in white paint, such as a silica or titanium dioxide (TiCk), can be disbursed in an otherwise transparent first adhesive layer 517 to provide diffuse reflectance of light back to the light guide plate 407.

[0067] In some embodiments, features of the light apparatus 101 discussed above can provide a relatively thin design that can reduce weight and enhance appearance while still maintaining the structural integrity of the light apparatus 101. For instance, referring to FIGS. 3 and 4, the second major surface 403 of the back plate 103 can comprise a first outermost surface of the light apparatus 101. The second major surface 430 of the display panel 107 can comprise a second outermost surface of the light apparatus 101. An overall thickness 449 of the light apparatus 101 is defined between the first outermost surface and the second outermost surface. In some embodiments, the overall thickness of the light apparatus is within a range of from about 2.35 mm to about 13.7 mm, such as from about 4.5 mm to about 7.1 mm.

[0068] It should be understood that while various embodiments have been described in detail with respect to certain illustrative and specific examples thereof, the present disclosure should not be considered limited to such, as numerous modifications and combinations of the disclosed features are possible without departing from the scope of the following claims.

Claims

What is claimed is:

1 A light apparatus comprising:

a back plate comprising a material comprising a linear coefficient of thermal expansion of from about 30 x 10⁷ /°C to about 100 x 10 ⁷ /°C at a temperature within a range of from 0°C to 300°C, the back plate comprising a first major surface, a second major surface, and a thickness defined between the first major surface and the second major surface;

a light guide plate comprising a material comprising a linear coefficient of thermal expansion about equal to the linear coefficient of thermal expansion of the back plate, the light guide plate comprising a first major surface, a second major surface, and a thickness defined between the first major surface of the glass light guide plate and the second major surface of the glass light guide plate; and

a first intermediate layer at least partially circumscribing a space defined between the back plate and the light guide plate, the first intermediate layer attaching the light guide plate to the back plate by contacting an outer portion of the first major surface of the light guide plate and the first major surface of the back plate, wherein the first intermediate layer comprises a Young’s Modulus of from about 50 MPa to about 100 GPa.

2. The light apparatus of claim 1, wherein the first intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

3. The light apparatus of any one of claim 1 and claim 2, further comprising a display panel and a second intermediate layer disposed between the light guide plate and the display panel, the display panel comprising a thickness defined between a first major surface of display panel and a second major surface of the display panel, the second intermediate layer attaching the display panel to the light guide plate by contacting the first major surface of the display panel and the second major surface of the light guide plate.

4. The light apparatus of claim 1, wherein the second intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible lights, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

5. The light apparatus of any one of claims 3 and 4, wherein the thickness of the display panel is from about 0.8 mm to about 1.8 mm.

6. The light apparatus of any one of claims 3-5, wherein the second major surface of the back plate comprises a first outermost surface of the light apparatus, the second major surface of the display panel comprising a second outermost surface of the light apparatus, and an overall thickness of the light apparatus is defined between the first outermost surface and the second outermost surface.

7. The light apparatus of claim 6, wherein the overall thickness of the light apparatus is within a range of from about 2.35 mm to about 13.7 mm.

8. The light apparatus of any one of claims 3-7, wherein the second intermediate layer comprises a Young’s Modulus that is less than the Young’s Modulus of the first intermediate layer.

9. The light apparatus of claim 8, wherein the Young’s Modulus of the second intermediate layer is from about 0.005 MPa to about 0.5 MPa.

10. The light apparatus of any one of claims 1-9, further comprising a light source optically coupled to an edge of the light guide plate.

11. The light apparatus of any one of claims 1-9, wherein the light guide plate comprises a rectangular light guide plate, wherein the first intermediate layer comprises a first segment extending along a first edge of the rectangular light guide plate, a second segment extending along a second edge of the rectangular light guide plate, and a third segment extending along a third edge of the rectangular light guide plate.

12. The light apparatus of claim 11, further comprising a light source optically coupled to a fourth edge of the rectangular light guide plate.

13. The light apparatus of any one of claims 1-12, wherein the material of the back plate comprises a Young’s modulus of from about 10 GPa to about 350 GPa.

14. The light apparatus of any one of claims 1-13, wherein the material of the back plate comprises glass.

15. The light apparatus of any one of claims 1-14, wherein the material of the light guide plate comprises a Young’s modulus of from about 60 GPa to about 90 GPa.

16. The light apparatus of any one of claims 1-15, wherein the material of the light guide plate comprises glass.

17. The light apparatus of any one of claims 1-16, wherein the back plate comprises an area that is larger than an area of the light guide plate.

18. The light apparatus of any one of claims 1-17, wherein the thickness of the back plate is within a range of from about 0.5 mm to about 5 mm.

19 The light apparatus of any one of claims 1-18, wherein the thickness of the light guide plate is within a range of from about 0.5 mm to about 5 mm.

20. The light apparatus of any one of claims 1-19, wherein the first intermediate layer comprises a thickness between the first major surface of the light guide plate and the first major surface of the back plate within a range of from about 0.05 mm to about 0.3 mm.

21. The light apparatus of any one of claims 1-20, wherein the display panel comprises a liquid crystal display panel.

22. A light apparatus comprising: a glass back plate comprising a first major surface, a second major surface, and a thickness defined between the first major surface and the second major surface; a glass light guide plate comprising a first major surface, a second major surface, and a thickness defined between the first major surface of the glass light guide plate and the second major surface of the glass light guide plate;

a first intermediate layer at least partially circumscribing a space defined between the glass back plate and the glass light guide plate, the first intermediate layer attaching the glass light guide plate to the glass back plate by contacting an outer portion of the first major surface of the glass light guide plate and the first major surface of the glass back plate, wherein the first intermediate layer comprises a Young’s Modulus of from about 50 MPa to about 100 GPa;

a display panel comprising a thickness defined between a first major surface of the display panel and a second major surface of the display panel;

a second intermediate layer attaching the display panel to the light guide plate by contacting the first major surface of the display panel and the second major surface of the light guide plate, the second intermediate layer comprising a Young’s Modulus that is less than the Young’s Modulus of the first intermediate layer; and

a light source optically coupled to an edge of the glass light guide plate.

23. The light apparatus of claim 22, wherein the first intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

24. The light apparatus of any one of claims 22 and 23, wherein the second intermediate layer includes a reflectance of from about 0.6 to about 0.99 for visible light, such as from 0.8 to 0.99, such as from 0.9 to 0.95.

25. The light apparatus of any one of claims 22-24, wherein the second major surface of the glass back plate comprises a first outermost surface of the light apparatus, the second major surface of the display panel comprises a second outermost surface of the light apparatus, and an overall thickness of the light apparatus is defined between the first outermost surface and the second outermost surface.

26. The light apparatus of any one of claims 22-25, wherein the display panel comprises a liquid crystal display panel.