JP2020518966A - Light guide having equiangular spiral curvature and device including the light guide - Google Patents

Abstract

The light guide has at least one light emitting surface and at least one light coupling surface, and at least a portion of the light coupling surface has a conformal spiral curvature. Also disclosed herein are optical assemblies that include at least one light source optically coupled to the light guides, as well as display devices, lighting devices, and electronic devices that include such assemblies.

Description

Related application

This application is related to US provisional application No. 62/500775 filed on May 3, 2017 and US provisional application No. filed on November 29, 2017 under Section 119 of the US Patent Law. No. 62/592,147, which claims the benefit of priority, the content of each application is the subject matter of which the present application is relied upon and is hereby incorporated by reference in its entirety.

The present disclosure relates generally to light guides having at least one light coupling surface having a conformal spiral curvature, and display devices and lighting devices including such light guides.

Liquid crystal displays (LCDs) are commonly used in various electronic devices such as mobile phones, laptops, electronic tablets, TVs and computer monitors. Conventional LCDs typically include blue light emitting diodes (LEDs) and color conversion elements such as light emitters or quantum dots (QDs). LEDs can also be used in lighting applications, eg in combination with color conversion elements in luminaires. For example, blue light from an LED can be directed through a color conversion medium that, upon passage, can convert some of the light into green and/or red light. The combination of blue, green and red light is perceived by the human eye as white light.

Color conversion elements, such as light emitters and QDs, do not have 100% quantum efficiency in the converted light and some of the light energy can be absorbed as heat by the color conversion element. Additionally, the color conversion process itself can generate heat due to, for example, Stokes shift during conversion from short wavelengths to long wavelengths. In some cases, 20% to 40% of the absorbed light is converted to heat. Excessive heat can degrade the color conversion element, so it is important to establish a suitable cooling or heat sink path to dissipate the heat generated and maintain the color conversion element within the desired operating temperature. sell. While phosphor materials are capable of operating at moderate temperatures (eg, up to about 300°C), QD materials are extremely temperature sensitive and can be subject to degradative effects at temperatures above about 100°C.

Due to the temperature sensitivity of QDs, conventional backlight units (BLUs) are generally configured to avoid close proximity and/or direct contact between QDs and LEDs. Such a configuration may be referred to as a "remote" configuration. For example, as shown in the LCD assembly of FIG. 1, the QD is a glass that can be placed above (but not in direct physical contact with) an LED array 2 placed on a printed circuit board (PCB) 3. Alternatively, they are often provided in the form of polymer tubes, capillaries, sheets or films, for example QDEF (QD enhancement film) 1. Therefore, the light 4 emitted from the LED 2 can pass through the QD when traveling to the liquid crystal (LC) panel 5. The BLU 6 can further include a heat sink 7 attached to the PCB that can dissipate the heat generated by the LEDs.

However, the assembly does not provide sufficient cooling because the heat from the QD is dissipated primarily by natural or forced convection aerodynamic forces 8 passing through the gap between the LED and the QDEF. The thermal conductivity of QDEF itself is relatively low, and it does not benefit from direct thermal contact with heat sink 7. As such, the LCD assembly can operate at low light intensity and/or power to protect the QD from thermal degradation that can undesirably cause an overall reduction in display or illumination brightness. Additionally, such an assembly can cause significant material waste because the QDs are distributed evenly throughout the LED array rather than being discretely placed only above each individual LED in the array.

Therefore, it would be advantageous to provide an optical assembly that includes a patterned color conversion medium that can eliminate material waste and thus reduce the cost of such devices. It would also be advantageous to provide an optical assembly that includes a heat sink path or other cooling mechanism capable of dissipating the heat generated by the color conversion medium. Further, it would be advantageous to provide an optical assembly having a reduced total thickness.

The present disclosure, in various embodiments, relates to a light guide, the light guide having at least one light emitting surface and at least one light coupling surface, and at least a portion of the at least one light coupling surface. Has an equiangular spiral curvature.

The light guide may, in some embodiments, include a plate having a first major surface, an opposite second major surface and at least one edge surface, the at least one edge surface being a light coupling surface. including. In an alternative embodiment, the light guide may include a disc having a first major surface, an opposite second major surface and an edge surface, the edge surface comprising a light coupling surface. The second major surface of the lightguide plate or disc may include a light emitting surface. The light guide plate or disc first major surface is patternable to have at least one of a color conversion medium, a light scattering feature, and a reflective material. The reflective layer is capable of at least partially encapsulating the color conversion medium patterned on the first major surface.

According to various embodiments, the light guide can include an annulus having an inner wall surface, an outer wall surface and at least one edge surface, the at least one edge surface including a light coupling surface. In some embodiments, the outer wall surface comprises a light emitting surface. In an additional embodiment, the annulus comprises a hollow cylinder. According to another embodiment, the light guide may include a rod having a first end surface, a second end surface, an outer wall surface and an edge surface, the edge surface including a light coupling surface. At least one of the first end surface, the second end surface and the outer wall surface may include a light emitting surface.

Also disclosed herein is an optical assembly including at least one light source optically coupled to the light guide, eg, optically coupled to at least one light coupling surface. In various embodiments, at least one light source is bonded to the printed circuit board. The optical assembly, in certain embodiments, can further include a transparent substrate having a major surface patterned with at least one of a color conversion medium, a light scattering feature, and a reflective material. A reflective layer is capable of at least partially encapsulating a patterned color conversion medium on a major surface of a transparent substrate. According to a non-limiting embodiment, the optical assembly can further include a diffusing layer disposed near at least one light emitting surface of the light guide.

The optical assembly can include a stack having, for example, a thickness of less than about 10 mm or less than about 5 mm. The light guide and/or the transparent substrate can include glass, plastic or combinations thereof. Also disclosed herein are display devices, lighting devices, and electronic devices that include such light guides and optical assemblies or arrays thereof.

Additional features and advantages of the disclosure are set forth in the following detailed description, some of which are readily understood by one of ordinary skill in the art from such a description, or the following detailed description, claims and Those skilled in the art will be aware of the practice of the methods described herein, including the accompanying drawings.

While both the general description above and the following detailed description present various embodiments of the disclosure, they are intended to provide an overview or framework for understanding the nature and character of the claims. Please understand what you are doing. The accompanying drawings are provided to provide a better understanding of the disclosure and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure and, together with the description, are used to explain the basic schemes and operations of the disclosure.

The following detailed description can be better understood when read in connection with the following figures, where like reference numerals are used to refer to like elements where possible.
It is a figure which shows an example of LCD assembly. FIG. 6 is a side view of a lightguide plate according to a disclosed embodiment. FIG. 6 is a plan view illustrating a light guide plate according to an embodiment disclosed. FIG. 6 is a perspective view illustrating a light guide plate according to an embodiment disclosed. FIG. 7 is a side view of a lightguide disc in accordance with a disclosed embodiment. FIG. 6 is a plan view illustrating a light guide disc according to a disclosed embodiment. FIG. 6 is a perspective view of a lightguide disc in accordance with a disclosed embodiment. FIG. 6 is a side view of a lightguide annulus according to a disclosed embodiment. FIG. 6 is a plan view showing a light guide annulus according to a disclosed embodiment. FIG. 6 is a perspective view illustrating a light guide annulus according to a disclosed embodiment. FIG. 7 is a side view of a lightguide rod according to a disclosed embodiment. FIG. 6 is a plan view illustrating a light guide rod according to an embodiment disclosed. FIG. 6 is a perspective view illustrating a light guide rod according to an embodiment disclosed. FIG. 6 illustrates total internal reflection at a lightguide plate that includes at least one edge having a conformal spiral curvature according to another embodiment of the disclosure. FIG. 5 illustrates a coordinate system used to form a constant angle of incidence curve according to various embodiments of the disclosure. FIG. 7 illustrates a constant angle of incidence curve according to additional embodiments of the disclosure. FIG. 7 shows a light guide with a truncated light coupling surface having a conformal spiral curvature. FIG. 7 shows a light guide having a light coupling surface with two conformal spiral curvature profiles. FIG. 6 shows ray tracing paths for a light coupling surface having a single conformal spiral curvature profile. FIG. 5 is a diagram showing ray tracing paths of an optical coupling surface having a plurality of conformal spiral curvature profiles. FIG. 11B is an enlarged view of the ray tracing path shown in FIG. 11A. FIG. 11B is an enlarged view of the ray tracing path shown in FIG. 11B. 6 is a graph showing a plot of light source alignment tolerances for a light guide having a light coupling surface with a single conformal spiral curvature profile and a plurality of conformal spiral curvature profiles. FIG. 6 is a side view showing a light guide plate having a main surface on which a color conversion medium is patterned and including a reflection layer. FIG. 6 is a side view showing a light guide plate having a main surface on which a color conversion medium and a reflective material are patterned. FIG. 3 is a side view showing a substrate having a major surface on which a color conversion medium is patterned and including a reflective layer. FIG. 6 shows an optical assembly including a combination of light guide and substrate. FIG. 6 is a plan view showing a substrate on which a color conversion medium is patterned. It is a top view which shows the substrate by which the color conversion medium and the reflective material were patterned. It is a perspective view which shows the multilayer substrate containing a color conversion layer and a reflective layer. FIG. 6 illustrates an optical assembly according to various embodiments of the disclosure. FIG. 6 illustrates an optical assembly array according to another embodiment of the disclosure. FIG. 6 illustrates an optical assembly array according to another embodiment of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to certain embodiments of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to certain embodiments of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to certain embodiments of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to another embodiment of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to another embodiment of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to another embodiment of the disclosure. FIG. 6 illustrates a light emission intensity profile of an optical assembly according to another embodiment of the disclosure. FIG. 6 illustrates an optical assembly according to various embodiments of the disclosure. FIG. 6 illustrates an output illumination profile for an optical assembly according to a disclosed non-limiting embodiment. FIG. 6 illustrates an output illumination profile for an optical assembly according to a disclosed non-limiting embodiment.

Various embodiments of the disclosure will now be discussed with reference to FIGS. 2-22, which illustrate exemplary embodiments of light guides, optical assemblies, their components and their features or characteristics. A display device and a lighting device including the assembly are also disclosed herein. The following general description is intended to provide an overview of the claimed assemblies and devices, and throughout the disclosure, various aspects will be more specifically described with reference to the non-limiting illustrated embodiments. To consider. Embodiments are interchangeable in the context of the disclosure.

Disclosed herein is a light guide having at least one light emitting surface and at least one light coupling surface, wherein at least a portion of the at least one light coupling surface has a conformal spiral curvature. It is the body. Suitable materials from which the light guide can be constructed include optically transparent materials such as glass and plastic. As used herein, the term "transmissive" means greater than about 80% in the visible region of the spectrum (about 420-750 nm) of a light guide, substrate or material measured over a path length of 1 mm. Intended to have an optical transmission of. For example, the exemplary transmissive lightguide, substrate or material has a visible light range of greater than about 85%, such as greater than about 90%, or greater than about 95%, including the range and all subranges therein. Can have a light transmittance of.

Suitable transparent materials may include, for example, any glass known in the art for use in displays and other electronic devices. Exemplary glasses include, but are not limited to, aluminosilicate glass, alkali aluminosilicate glass, borosilicate glass, alkali borosilicate glass, aluminoborosilicate glass, alkali aluminoborosilicate glass and Other suitable glasses may be included. The substrates herein can be chemically and/or thermally toughened in various embodiments. Non-limiting examples of suitable commercially available substrates include, but are not limited to, Corning Incorporated's EAGLE XG(R), Lotus(TM), Iris(TM), Willow(R). And Gorilla®. According to some non-limiting embodiments, glass chemically strengthened by ion exchange may be suitable as the substrate. In other embodiments, polymeric materials such as plastics (eg, polymethylmethacrylate “PMMA”, methylmethacrylate styrene “MS” or polydimethylsiloxane “PDMS”) can be used as suitable permeable materials.

2-5 show a variety of non-limiting light guides 100A-100D, each having at least one light emitting surface and at least one light coupling surface, at least a portion of the light coupling surface. It has an equiangular spiral curvature. According to FIG. 2, the light guide 100A may be in the form of a sheet or plate having at least one edge surface 103. The light guide plate (LGP) 100A has a first main surface 101 and an opposite second main surface 102, either of which is operable as a light emitting surface. In the illustrated embodiment, the second major surface 102 can be used as a light emitting surface and the edge surface 103 can be used as a light coupling surface. At least a part of the edge surface 103 is shaped so as to obtain a conformal spiral curvature. 2A-2C show a symmetrical and rectangular LGP 100A having two light coupling surfaces (eg, edge surface 103), the LGP 100A has a symmetrical shape and asymmetry with less than or more than 4 edges. It should be understood that it may have any regular or irregular polygonal shape, including various shapes, such as triangles, squares, diamonds, trapezoids, pentagons, hexagons and other suitable shapes. Shapes that include at least one curvilinear edge surface 103 are also contemplated herein. Additionally, the first major surface 101 and the second major surface 102 are shown as planar and parallel in FIGS. 2A-2C, but each of these surfaces has one or more axes of curvature. It should be understood that they may be included and/or may not be parallel to each other.

As shown in FIGS. 3A to 3C, the light guide body 100B may be in the form of a disc having an edge surface 103. Similar to FIGS. 2A-2C, the lightguide disc 100B can also have a first major surface 101 and an opposite second major surface 102, either of which is operable as a light emitting surface. .. In the illustrated embodiment, the second major surface 102 can be used as a light emitting surface and the edge surface 103 can be used as a light coupling surface. At least a part of the edge surface 103 is shaped so as to obtain a conformal spiral curvature. Although FIGS. 3A-3C show a symmetric and circular lightguide disc 100B, disc 100B can be any regular or irregular shape, including curved edge surfaces, including symmetrical and asymmetrical shapes. It should be understood that, for example, it may have a circular shape, an oval shape and other free curved shapes. Additionally, the first major surface 101 and the second major surface 102 are shown as planar and parallel in FIGS. 3A-3C, but each of these surfaces has one or more axes of curvature. It should be understood that they may be included and/or may not be parallel to each other.

4A-4C, the light guide 100C may additionally be in the form of a hollow annulus having an edge surface 103, an outer wall surface 104 and an inner wall surface 104'. In the illustrated embodiment, the outer wall surface 104 can be used as a light emitting surface and the edge surface 103 can be used as a light coupling surface. At least a part of the edge surface 103 is shaped so as to obtain a conformal spiral curvature. 4A-4C show a symmetrical and cylindrical lightguide annulus 100C having a circular cross-sectional shape, the annulus 100C having a symmetrical shape and asymmetry with one or more straight or curved edges. It is understood that it may have any regular or irregular cross-sectional shape, including circular, oval, triangular, square, rhombic, trapezoidal, pentagonal, hexagonal and other suitable cross-sectional shapes, including I want to be done.

5A-5C, the light guide 100D may further be in the form of a rod having an edge surface 103, an outer wall surface 104, a first end surface 106 and a second end surface 107. In the illustrated embodiment, the outer wall surface 104, the first end surface 106 and/or the second end surface 107 can be used as a light emitting surface, and the edge surface 103 can be used as a light coupling surface. At least a part of the edge surface 103 is shaped so as to obtain a conformal spiral curvature. 5A-5C show a symmetrical and cylindrical light guide rod 100D having a circular cross-sectional shape, the rod 100D having a symmetrical shape and asymmetry with one or more straight or curved edges. It is understood that it may have any regular or irregular cross-sectional shape, including circular, oval, triangular, square, rhombic, trapezoidal, pentagonal, hexagonal and other suitable cross-sectional shapes, including I want to be done.

2-5, the edge surface 103 is generally shown as having a convex curved surface for ease of reference, although the specific nature of its conformal spiral curvature and the resulting shape. Will be discussed in more detail below. Conformal spiral curvature is also discussed in US Provisional Application No. 62/347351 filed June 8, 2016, which application is incorporated herein by reference in its entirety. ..

The curvature of the light coupling surface (eg, edge surface 103) of the light guide depends, in some embodiments, on the desired optical path of the light emitted by the light source that is optically coupled to the light guide. For example, according to FIG. 6, the curvature of the light coupling surface 105 is such that the light 110 emitted from the light source (eg, LED) 111 optically coupled to the light guide 100 is critical to the inner side 105 ′ of the light coupling surface 105. It can be designed to hit at angles greater than the angle and to be “trapped” within the lightguide by total internal reflection (TIR). As used herein, the term "optical coupling" refers to the fact that a light source is positioned relative to a light guide for introducing or entering light into the light guide. Intended for display. The light source can be optically coupled to the light guide even though it is not in direct physical contact with the component. In some embodiments, the light source is optically coupleable to at least one light coupling surface 105. According to various embodiments, for example, as shown in FIG. 6, the light source 111 includes a first light source 111 near the light coupling surface 105 such that the light is incident on the inner side 105 ′ of the light coupling surface 105. It can be arranged on the main surface 101 or in the vicinity thereof.

Total Internal Reflection (TIR) is a technique in which light propagating in a first material having a first index of refraction (eg, glass, plastic, etc.) has a second index of refraction that is lower than the first index of refraction. This is a phenomenon in which it can be completely reflected at the interface with a material (for example, air). TIR is Snell's law, which describes the refraction of light at the interface between two materials with different refractive indices:

Can be described using. According to Snell's law, n ₁ is the refractive index of the first material, n ₂ is the refractive index of the second material, and θ _i is the angle of the incident light at the interface with respect to the normal to the interface. (Incident angle), and θ _r is a refraction angle of refracted light with respect to the normal line. When the refraction angle (θ _r ) is 90° and, for example, sin(θ _r )=1, Snell's law is

Can be expressed as The incident angle θ _i under the condition may be referred to as a critical angle θ _c . Light having an incident angle larger than the critical angle (θ _i >θ _c ) undergoes total internal reflection in the first material, while light having an incident angle equal to or smaller than the critical angle (θ _i ≦θ _c ). Light is emitted from the first material.

In the example case of the interface between air (n ₁ =1) and glass (n ₂ =1.5), the critical angle (θ _c ) can be calculated to be approximately 42°. Therefore, when the light propagating in the glass strikes the interface between air and glass at an incident angle of more than 42°, all incident light is reflected from the interface at an angle equal to the incident angle. When the reflected light strikes the second interface having the same refractive index relationship as the first interface, the light incident on the second interface is also reflected at the reflection angle equal to the incident angle.

Thus, one or more edge surfaces of the light guides disclosed herein “trap” light, eg, unless there is a change in interface conditions or until a change in interface conditions occurs. Light incident on the light coupling surface of the light guide may be repeatedly propagated within the light guide and may be, for example, reflected such that it is reflected along the light coupling surface 105 (eg, edge surface 103). It is reflected between the other surfaces of the optical body (for example, the first main surface 101, the second main surface 102, the outer wall surface 104 and the inner wall surface 104′ and/or the first end surface 106 and the second end surface 107). Is configurable. In some embodiments, the curvature of the light coupling surface 105 (eg, edge surface 103) is such that substantially all light 110 emitted from the light source 111 has an incident angle regardless of whether the light source itself has an origin. It can be designed to hit the optical coupling surface with θ _i [where θ _i >θ _c ]. For example, the light 110 emitted from the upper corner(s) of the light source 111 may have a minimum angle of incidence with respect to the light coupling surface 105, so that the light coupling surface 105 may be removed from that location on the light source 111. Even the emitted light can be configured to have an incident angle θ _i that is greater than the critical angle θ _c . According to a non-limiting embodiment, at least one light coupling surface 105 (eg, edge surface 103) of the light guide is configured such that substantially all of the light from the light source 111 has a constant angle of incidence (θ _i ) [where [theta] _i =k>[theta] _c ] can be configured to hit the optical coupling surface 105 (for example, the edge surface 103).

The constant incident angle curve r(θ) of the light coupling surface can be constructed by defining a coordinate system with the origin defined at the upper corner of the light source. As shown in FIG. 7, the tangent vector to the curve r(θ)

Is equation (1), that is,

Can be drawn using

Is a unit vector representing the direction of the ray,

Is

Is a unit vector orthogonal to. Note that

and

The dot product of is

Can be expressed by where α is

When

Is the angle formed by. Since the angle of incidence is the complement of α, equation (2) is given by the following equation (3):

Can be rewritten as Equation (3) is further differentiated in polar coordinates by equation (4):

Can be simplified to obtain The solution of Equation (4) is Equation (5), that is,

, Where r(0) is the starting point or origin of the curve r(θ) at θ=0.

FIG. 8 shows an exemplary constant incident angle curvature to the light coupling surface, where r(0)=0.4 mm and θ _i =42°. The range [0<θ<π] of the angle θ of the light emitted from the light source 111 is shown, and the incident angle θ _i =42° with respect to the edge surface is generated. Note that for angles θ>π, the constant angle of incidence curve defines a helix, also called a logarithmic spiral, a conformal spiral or a growth spiral. Thus, a light coupling surface having a constant angle of incidence curvature may include at least one region having a conformal helix curvature. In some embodiments, substantially all light coupling surfaces can have a conformal spiral curvature. In other embodiments (eg, the truncated surface case shown in FIG. 9), at least a portion of the light coupling surface may have a conformal spiral curvature.

The extreme value of the curve r(θ) [0<θ<π] can be expressed as an angle θ _p =θ _i +π/2. The Cartesian coordinates of the extreme value are expressed by the equations (6a) and (6b), that is,

Can be expressed by The boundary or maximum bound 116 of the right convex surface of the y-axis occurs at the angle θ _i . Thus, the Cartesian coordinates for the rightmost point are equations (7a) and (7b), that is,

Can be expressed by The value of x _r can be used to determine the maximum radius of the light source that can be optically coupled to the edge surface.

According to FIG. 9, the light coupling surface 105 of the light guide is at least partially truncated so as to include more than one portion in certain embodiments. The first portion 105A may include straight edges that may or may not be orthogonal to the horizontal centerline of the lightguide 100, and in various embodiments, at various angles to the centerline, such as The angle may range from about 80° to about 100°, for example from about 85° to about 95°, for example about 90°. At least a portion of the light coupling surface 105, eg, the second portion 105B, may have a conformal spiral curvature. According to additional embodiments, as shown in FIG. 10, the light coupling surface 105 can include two or more portions having a conformal spiral curvature. For example, the second portion 105B can have one conformal spiral curvature profile and the third portion 105C can have another conformal spiral curvature profile, these profiles being equal or different, and And/or have different or equal constant angles of incidence θ _i . Of course, additional parts with additional profiles can be provided without limitation.

The ray tracing path from the light source to the light guide is shown in detail at two levels in FIGS. 11A, 11B and 12A, 12B (enlarged view). 11A and FIG. 12A (enlarged view) show a ray tracing path of a light guide having a straight edge portion and two conformal spiral curvature profile portions, and FIGS. 12B shows a ray tracing path of a light guide having a straight edge portion and a single conformal spiral curvature profile portion. Without wishing to be bound by theory, it is believed that the incorporation of two or more conformal spiral curvature profiles with straight edge portions as a selection means can reduce the effect of misalignment of the light source on optical coupling efficiency. The position of the light source with respect to the light guide can be critical and can affect the amount of light that leaks through the edges of the light guide. The light source can theoretically be arranged such that the light leakage is minimal, but the actual position of the light source in practice is not limited to the following, but the manufacturing tolerance of the printed circuit board (PCB), Various misalignment angles may be included due to several factors, including warpage of the PCB and/or PCB backing structure, soldering of the light source(s) to the PCB. If the light source is offset from its ideal position, for example if the light source extends beyond the edge of the light guide, a large amount of light may be lost as light leakage. By providing an additional curvature profile (eg, the third portion 105C in FIG. 10), some of these potential light leaks can be captured and redirected into the light guide.

FIG. 13 is a graph plotting light leakage from a light guide as a function of LED misalignment. Output leakage is the output output through the light guide edge(s), the output output through the light emitting surface(s) and the light guide edge(s). Calculated as the sum of the output and the output. A positive number of misalignments represents misalignment in the direction of the truncated edge of the lightguide. The misregistration in FIG. 13 is limited to −0.1 mm in the negative direction, which means that any further misregistration in that direction will result in a TIR for the conformal spiral curvature profile(s). This is because the satisfaction of the condition may cause an error. Even at an ideal light source position (zero misalignment), light leakage is 20% for lightguides with a single conformal spiral curvature profile (Plot A), multiple conformal spiral curvature profiles It is 21% for the light guide (plot B). Some of the power leaks between the light source and the light guide, and the rest of the leak can be caused by light exiting the light guide edge after multiple reflections within the light guide. If the light source has a misalignment of 0.12 mm, the light leakage increases from 20% to 25% for a single profile lightguide. However, even if there is the same amount of positional deviation, light leakage does not increase in the light guides having a plurality of profiles. As shown in FIG. 13, the light guides of a plurality of profiles can tolerate the positional deviation of the light source up to 0.41 mm, as compared with the light guide of a single profile that can only tolerate the positional deviation of 0.22 mm An 86% improvement in misalignment tolerance is obtained.

2-5, at least one light source 111 may be optically coupled to light guides 100A-100D to form an optical assembly. For example, one or more light sources can be located near the edge surface 103. In the case of the light guide plate 100A or the light guide disc 100B, the light source can be arranged on the first main surface 101 near the edge surface 103 or in the vicinity thereof. The cross-sectional views shown in FIGS. 2A, 3A, 4A, and 5A show two light sources 111 on each of the opposing edge surfaces 103. However, it should be understood that multiple light sources can be arranged along one or more light coupling surfaces. For example, multiple light sources can be arranged along opposite edge surfaces, eg, as shown in FIG. 2B. In other embodiments, multiple light sources may be arranged along a single light coupling surface as shown in FIGS. 3B, 4B and 5B. Alternatively, in the case of a light guide with multiple edge faces, for example a square or rectangular light guide, one or more light sources can be placed along any one or more edge faces without restriction. Is.

Each size of the light guide body 100 may depend on the size of the light source 111. In certain embodiments, the thickness of light guide 100 is scalable to approximately align with the narrowest dimension of light source 111. For example, a lightguide optically coupled to a 0.7 mm x 0.7 mm LED can have a thickness of less than 5 mm. Thus, the thickness of the lightguide, including the range and all subranges therein, is in the range of about 1 mm to about 10 mm, such as about 2 mm to about 9 mm, about 3 mm to about 8 mm, about. It can range from 4 mm to about 7 mm or about 5 mm to about 6 mm. In some embodiments, the thickness of the lightguide is less than about 5 mm, including less than about 5 mm, such as less than about 4.5 mm, less than about 4 mm, less than about 3.5 mm or about including the range and all subranges therein. It may be less than 3 mm, for example in the range of about 3 mm to about 5 mm.

As shown in FIGS. 14A and 14B, one or more surfaces of light guide 100 can be patterned to have color conversion media, light scattering or diffusing features, and/or reflective materials. In the illustrated non-limiting embodiment, the first major surface 101 includes the color conversion medium 112 and the reflective layer 135. Alternatively, as discussed in more detail below, the color conversion medium 112, the light scattering features and/or the reflective layer 135 may be a separate component that may be provided in an optical assembly including the light guide 100, eg, a transparent substrate. Can also be provided. The color conversion medium 112 can include at least one color conversion element, such as a light emitter, quantum dots and/or luminophores, such as a phosphor and/or a light emitting polymer. The color conversion medium 112 or light scattering features may form regions of modified interface conditions such that reflected light incident on the color conversion medium 112 or light scattering features is forward scattered at angles less than the critical angle θ _c. .. In certain embodiments, the color conversion medium can be used for the dual purpose of scattering incident light and converting it to different wavelengths.

As shown in more detail in FIG. 6, the light 110 emitted by the light source 111 is generated in the light guide 100 due to the TIR promoted by the curvature of the light coupling surface 105 (eg, the edge surface 103), It can be reoriented. In this case, the TIR within the light guide may be “destroyed” or interrupted in the areas where the color conversion media 112 are distributed so that the light 110 can escape from the light guide 100 as outgoing light 110 ′. The color conversion medium is also capable of modifying the light 110 such that the emitted light 110' has a different wavelength than the original wavelength of the light 110.

The reflective layer 135 can be disposed on the major surface of the light guide 100 and can encapsulate at least a portion of the color conversion medium 112 or light scattering features (not shown). In a non-limiting embodiment, the reflective layer may include a metal film, such as a film including one or more of Al, Au, Ag, Pt, Pd, Cu, alloys thereof, and combinations thereof. According to various embodiments, multiple layers of metal film, such as a silver layer coated with an aluminum layer, can also be used. In certain embodiments, the reflective layer 135 can include a material that has a high thermal conductivity, such as a material that can dissipate heat from the color conversion medium 112. Further, the reflective layer 135 may also include a ductile material that is expandable and/or stretchable under thermal stress (eg, due to thermal expansion of the color conversion material) without the appearance of cracks or pores. .. Thus, the reflective layer 135 can be used both as a heat path to dissipate heat from the color conversion medium 112 and/or as an airtight barrier to prevent deterioration of the color conversion medium 112 due to moisture and/or air. Other arrangements of color conversion medium 112, light scattering features and reflective layer 135 are discussed in more detail below. It should be understood that these embodiments are interchangeable with the embodiments shown in FIGS. 2-5 without limitation.

As an alternative to delivering light directly through the color conversion medium (“delivery” mode), the optical assemblies disclosed herein may, for example, allow light to be spread over a larger area before it strikes the color conversion medium. The light emitted by the light source is reflected one or more times using a light guide having at least one light coupling surface disclosed herein having a predetermined curvature at ("reflecting" mode). Is configurable. In this way, the luminous flux in the device can be significantly reduced to two orders of magnitude or more. In other words, the reflected light incident on the color conversion medium may have an intensity of less than 10% or less than 1% of the original light emitted from the light source. Moreover, because light can also be reflected from the reflective surface below the color conversion medium, the reflective mode configuration can also have the additional benefit of passing light through the color conversion medium more than once, and thus at different wavelengths. Opportunity for conversion of light to is increased.

Also, the use of a "remote" configuration, in which the color conversion medium is spaced from the light source, in combination with a "reflective" mode not only reduces the light flux to which the medium and/or the base material is exposed, but also occurs. An additional heat sink path is also formed that dissipates all of the heat. In addition, the “remote” configuration allows the LEDs to operate at lower temperatures, thus eliminating the need to use thermal pathways to cool the color conversion medium (eg, in the case of conformal coating of phosphors). It has the additional advantage of being efficient. Therefore, the life of the optical assembly may also be extended compared to prior art devices, due to one or more of the advantages described above.

As discussed above with respect to FIG. 14A, lightguide 100 can have at least one surface patterned to have a color conversion medium, a light scattering feature and/or a reflective material. As used herein, the term "patterning" may mean that media, features and/or materials are in the plane of the light guide or substrate, for example randomly or planned. Well, which may be repetitive or non-repetitive, intended to be indicia of being present in any given pattern or design, which may be uniform or non-uniform ing. As discussed herein, the pattern may have a slope from one edge of the substrate to the other edge.

Regarding the light guide plate 100A of FIGS. 2A to 2C or the light guide disc 100B of FIGS. 3A to 3C, one or both of the first main surface 101 and the second main surface 102 is a color conversion medium, a light It can be patterned to have at least one of a scattering feature and a reflective material. In some embodiments, the second major surface 102 can be a light emitting surface and the first major surface 101 is patterned to have a color conversion medium, a light scattering feature and/or a reflective material. be able to. For the lightguide annulus 100C of FIGS. 4A-4C, one or both of the outer wall surface 104 and the inner wall surface 104' can be patterned to have at least one of a color conversion medium, a light scattering feature and a reflective material. Is. In various embodiments, the outer wall surface 104 can be a light emitting surface and the inner wall surface 104' can be patterned to have a color conversion medium, light scattering features and/or reflective material. With respect to the light guide rod 100D of FIGS. 5A-5C, the outer wall surface 104 can be patterned to have at least one of a color conversion medium, a light scattering feature and a reflective material, and the first end surface 106 and/or Alternatively, the second end surface 107 can be the light emitting surface(s).

In some embodiments, the reflective layer 135 may be continuous, for example as shown in Figure 14A. In an additional embodiment, a discontinuous reflective layer 135' as shown in Figure 14B can also be incorporated. Since metals, such as aluminum, can be slightly absorptive, a continuous reflective metal coating can result in a slight attenuation of the light emitted from the light guide. Thus, in some embodiments, the reflective layer may be provided only in the area corresponding to the deposited portion of the color conversion medium 112. Thus, the region 137 may have a glass-air interface or a plastic-air interface that provides greater TIR. Additionally, although not shown, the portion of surface 101 corresponding to region 137 is provided with other light scattering features that can be used to achieve the desired color balance of the transmitted light, such as white scattering particles. You can also Although it is shown in FIG. 14B that the light guide 100 includes the patterned color conversion medium 112, the configuration shown in FIG. 14B and the configuration shown in FIG. 14A are similar to the transparent substrate 130 shown in FIG. 14C. Is also applicable. Substrate 130 can include any transparent material, such as glass and plastics disclosed herein. As shown in FIG. 15, the light guide body 100 may include at least one recess 150 in which the transparent substrate 130 may be bonded to the light guide body 100 or combined therewith. The transparent substrate can include one or more functional units including, but not limited to, color conversion, light scattering, light absorption, light reflection, polarization functional units, and combinations thereof.

FIG. 14C shows an alternative embodiment of the exemplary transparent substrate 130 having a first major surface 131 and a second major surface 132, the major surface 131 being patterned to have the color conversion medium 112. It is shown. The ink layer 138 can be provided between the color conversion medium 112 and the reflective layer 135. The ink layer 138 can include, for example, a reflective white ink, such as a metal oxide (eg, TiO ₂ ), and can be used to partially or completely obscure the reflective layer 135 from view. If desired, the ink layer 138 can also be applied to areas where the color conversion medium 112 is not present, along the entire first major surface 131 of the transparent substrate 130, as shown in FIG. 14C. Alternatively, the ink layer 138 can be provided only in the area containing the color conversion medium 112. Although FIG. 14C shows the transparent substrate 130 including the patterned color conversion medium 112, the configuration shown in FIG. 14C is also applicable to the light guide body 100. The transparent substrate may alternatively include a major surface patterned to have a color conversion medium and/or a reflective material having the configuration shown in FIGS. 14A, 14B.

The color conversion medium can be deposited using any method known in the art. Suitable deposition methods include printing, such as inkjet printing, screen printing, microprinting and the like, coatings such as spin coating, slot coating, dip coating and the like, drop casting, pipetting, photolithography. Or any combination thereof may be included. In certain embodiments, drops of color conversion medium suspended in one or more solvents can be deposited on the surface of the light guide or substrate in any desired pattern. The solvent(s) can be removed by drying at ambient temperature or elevated temperature as a selection means. Similarly, the color conversion medium may include photoresist that can be selectively removed using a photomask having a desired pattern. In some embodiments, the quantum dot suspended photoresist may include a scattering medium for scattering blue light. Light scattering features, such as TiO ₂ particles, can be printed on the surface and/or can be provided by etching or laser damaging on or under the surface.

The color conversion medium 112 and/or light scattering features may also be encapsulated or encapsulated by a protective layer, such as a reflective layer 135, as shown in Figures 14A-14C. The method of depositing the reflective layer can include, for example, a sputtering process or a vapor deposition process. For example, the color conversion medium 112 can be deposited on the major surface of the light guide 100 or the substrate 130, such as a glass or plastic substrate, and subsequently, such that the color conversion medium 112 is at least partially encapsulated. A protective metal film can be sputtered or deposited on the surface. In various embodiments, the light guide or substrate and the reflective layer can form an airtight capsule containing a color conversion medium.

In additional embodiments, the light guide or transparent substrate may have one or more cavities in which color conversion media can be deposited. The cavities can be provided by, for example, pressing, molding, cutting or any other suitable method. According to additional embodiments, the reflective layer includes about 0.1 μm to about 10 μm, such as about 0.5 μm to about 9 μm, about 1 μm to about 8 μm, including the range and all subranges therein. Can have a thickness in the range of about 2 μm to about 7 μm, about 3 μm to about 6 μm, or about 4 μm to about 5 μm.

According to various embodiments, the color conversion medium and/or the light scattering features are of a suitable density that results in a substantially uniform light output intensity across the light guide, with a main density of the light guide or transparent substrate. The surface can be patterned. An exemplary pattern is shown in FIG. 16A with areas A having increased density and areas B-E having decreased density. In each region, each individual dot represents a discrete "island" of the color conversion medium. In some embodiments, the density of the color conversion medium may be greater in area A than area B, in area B greater than area C, in area C greater than area D, and in area D greater than area E. It may be large, for example A>B>C>D>E.

In certain embodiments, the density of the color conversion medium and/or light scattering features near the light source is one end to the other suitable for forming a desired light output distribution across the light guide, for example. May be higher than the density at points further from the light source, and vice versa, so that a gradient to Referring again to FIG. 16A, the position of the light source (not shown) is indicated by the plurality of apertures 140. Aperture 140 may, for example, allow the color conversion medium in the area of the light source, the light scattering features, to allow light to enter the lightguide without returning by reflection at the reflective layer and directly passing through the area of the color conversion medium. It may be formed such that the reflective layer and/or the reflective layer is removed. Aperture 140 is, in some embodiments, a photolithographic technique that selectively removes the color conversion medium and/or reflective layer from desired areas, or a mechanical means of removing a portion of the substrate to form a void. Can be formed using, for example, machining. The pattern shown in FIG. 16A can be applied directly to the light guide or a separate transparent substrate.

FIG. 16B illustrates another exemplary pattern of color conversion media and reflective material. The color conversion media 112 may be arranged in a continuous or more dense manner in an area near the light source (not shown), the position of which is indicated by the aperture 140. The color conversion medium 112 can be patterned with increased density in areas further from the light source, such as the central area shown in FIG. 16B. As a selection means, a continuous sheet of color conversion medium can be machined to remove the color conversion medium in the desired areas to form empty voids, which are then filled with a discontinuous reflective layer 135'. It is possible. In the illustrated embodiment, a single layer may include an island of reflective layer 135 ′ surrounded by color conversion medium 112. The pattern shown in FIG. 16B can be applied directly to the light guide or a separate transparent substrate.

In an alternative embodiment, the multilayer substrate may be provided in an optical assembly, such as the configuration shown in Figure 16C. A continuous sheet of color conversion medium 112 (e.g., QDEF from 3M or RN16-006 from Nanoco) can be machined to remove the color conversion medium in desired areas to form empty voids 155. A separate reflective layer 135 (eg, 3M ESR) can then be inserted between the color conversion medium and the backing sheet 160 as a selection means and adhered to the machined color conversion medium. The backing sheet 160 may be provided in some embodiments to provide additional mechanical support for the multilayer sheet, or in other embodiments eliminated to reduce the total thickness of the optical assembly. You can also The backing sheet 160 can be constructed of any of the materials disclosed herein, including glass, plastic and metal. In some embodiments, the backing sheet 160 may include a heat conductive material, such as metals such as aluminum, silver, copper and the like.

Returning to FIG. 8, it should be noted that rays that reflect along regions of conformal spiral curvature tend to travel along the top of the curve and thus may leave the gap 115 near the light source. Thus, the light striking the first major surface of the light source may have a non-uniform distribution, eg a low ray distribution near the light source. When patterning the color conversion medium 112 and/or the light scattering features on a light guide or transparent substrate, areas of increased density are placed near the light source(s), corresponding to the gap 115. can do. Therefore, in areas of high light distribution where excessively bright light intensity can occur, the density of the color conversion and/or light scattering islands is reduced so that the light rays strike the reflective layer and continue to be reflected within the light guide. The probability can be increased. In areas of low light distribution, eg near the light source, the density of the color conversion and/or light scattering areas is increased so that the light rays hit the color conversion and/or light scattering areas and are scattered out of the light guide. The probability can be increased.

Since the color conversion medium and/or the light scattering features can be patterned to provide substantially uniform intensity of the emitted light, optical assemblies using the lightguides disclosed herein are otherwise In this case, it can be integrated into a device, for example a display device or a lighting device, without a gap between the light guide and the other parts of the device, which may require diffusion of the emitted light. Thus, even if the light guide is relatively thick, or if the optical assembly includes a diffusing layer, the overall thickness of the assembly can be reduced, as discussed in more detail below. In certain embodiments, the total thickness of the optical assembly can be less than about 10 mm, or less than about 5 mm.

The color conversion medium 112 can, in some embodiments, include at least one color conversion element that can be suspended in an organic or inorganic matrix, such as silicone or other suitable material. In certain embodiments, the color conversion element can be suspended in a thermally conductive matrix. According to various embodiments, the color conversion material has a thickness in the range of, for example, about 5 μm to about 400 μm, including all of the range and subranges therein, for example, about 10 μm to about 300 μm, about 20 μm. To about 200 μm, or about 50 μm to about 100 μm in thickness. The at least one color conversion element can be selected, for example, from light emitters, quantum dots (QDs) and luminophores, such as phosphors or light emitting polymers and the like. Exemplary emitters include, but are not limited to, red and green emitting emitters such as yttrium and zinc sulfide based emitters such as yttrium aluminum garnet (YAG), Eu ²⁺ doped red nitride. Objects, and combinations thereof.

The QD can change shape and/or size depending on the desired wavelength of emitted light. For example, the frequency of the emitted light can increase as the size of the quantum dots decreases, eg, the color of the emitted light shifts from red to blue as the size of the quantum dots decreases. Upon irradiation with blue light, ultraviolet light, or near-ultraviolet light, the quantum dots are capable of converting light into longer wavelength red, yellow, green or blue wavelengths. According to various embodiments, the color conversion element can be selected from QDs that emit at red and green wavelengths upon irradiation with blue, ultraviolet or near-ultraviolet light.

In various embodiments, the color conversion medium 112 can be configured to include the same or different types of color conversion elements, such as elements that emit light of different wavelengths. For example, in some embodiments, the light guide 100 or transparent substrate 130 can be patterned to have a mixture of color conversion elements that emits both green and red wavelengths, such as individual color conversion media. Each "island" of can include both red and green QDs. However, according to other embodiments, the individual islands may only include color conversion elements emitting the same wavelength, eg one island containing only green quantum dots, or one island being a red emitter. May include only. In another embodiment, a single region (eg, regions A-E in FIG. 16A) can be divided into, for example, wheel spokes, pie pieces, or checkerboard grids, with green conversion to every other subregion. The elements are filled with the red color conversion element in between. Such an embodiment can be significant, for example, in avoiding re-conversion of light, for example in avoiding re-conversion from green to red after conversion from blue to green or vice versa.

The choice of the color conversion pattern configuration and the type and amount of color conversion media to be placed at each location to achieve the desired display or lighting effect is within the discretion of one of skill in the art. Also, red and green emitting devices have been discussed above, but are not limited to red, orange, yellow, green, blue or any other color in the visible spectrum (eg, about 420 nm to 750 nm). It should be understood that any type of color conversion element capable of emitting light of any wavelength, including, can be used. For example, in solid state lighting applications, quantum dots with different dimensions can be combined for emulating blackbody output, which can provide good color rendering. Such a device can include, for example, color conversion elements of different types and/or different sizes that emit at different wavelengths, for example visible wavelengths. In some examples, combinations of color conversion elements that emit three or more different wavelengths, such as four or more, five or more, or six or more different wavelengths, can be used.

Devices The light guides and optical assemblies disclosed herein can be used in a variety of applications, including, but not limited to, display applications and lighting applications. For example, a lighting device, such as a luminaire or solid state lighting device, can include a light guide or an optical assembly disclosed herein. Also, the light guide and optics assembly can be incorporated into a TV, computer, handheld device or similar display, such as a backlight unit (BLU).

For example, FIG. 17 illustrates a cross-sectional view of an exemplary optical assembly 200 that includes the light guide 100 disclosed herein. The optical assembly may further include a printed circuit board (PCB) 122 on which one or more light sources 111 may be mounted, for example by soldering. In certain embodiments, the PCB can be attached to at least one heat sink (not shown). The PCB 122 can also be provided with one or more thermal vias (not shown) that can be placed to form the heat sink path. The thermal vias, in some embodiments, are made of a conductive material (eg, metal, eg, Cu, Ag, etc.) that allows heat to be transported from one side of the PCB 122 to the other side and to a heat sink (if present). It may include holes or openings in the PCB 122 that are filled.

In certain embodiments, as shown in FIG. 17, a spacer substrate 126 having at least one cavity 128 as a selection means can be used to provide a housing for the light source 111. In other embodiments (not shown), a transparent substrate 130 can be provided in the assembly, which is positioned relative to the PCB 122 to provide a housing for the light source(s) 111. It may have one or more cavities (not shown) that are matable. An adhesive layer 124, such as thermal tape or silicone tape, can be used to attach the spacer substrate 126 to the PCB 122. A light source medium 134, such as silicone, can be used to fill the cavity of the spacer substrate 126 (or substrate 130). However, in some embodiments, the cavity may not be filled with media, for example the cavity may contain air.

In the optical assembly 200 shown in FIG. 17, the transparent substrate 130 includes a color conversion medium, a light scattering feature and/or a reflective material (not shown), such as shown in FIGS. 14A-14C or 16A-16C. It is possible to pattern. The adhesive layer 124 can be used to attach the transparent substrate 130 to the spacer substrate 126 (if present) or to the PCB 122. Similarly, the light guide body 100 can be attached to the transparent substrate 130 using the adhesive layer 124. In certain embodiments, one or more or all of the adhesive layers 124 can include an optically clear adhesive. In additional embodiments, one or more or all adhesive layers 124 can include a heat conductive adhesive. In yet another embodiment, one or more or all of the adhesive layers 124 can have an index compatible with the light guide and/or the transparent substrate, such as the index of refraction of the light guide and/or the transparent substrate. It can have a refractive index within 5%.

According to additional embodiments, the light guide 100 may include plastic and the transparent substrate 130 may include glass. Of course, as discussed above, the lightguide 100 has a major surface patterned to have a color conversion medium (eg, as shown in FIGS. 14A-14B) and/or a light scattering feature and/or a reflective material. In such an embodiment, the transparent substrate 130 may not be present in the device. The light guide 100 is positionable relative to the PCB 122 so that the light source(s) 111 are near the edge surface(s) (not numbered) of the light guide 100. Will be placed.

Although not shown in FIG. 17, the optical assembly may further include a diffusing layer that may be provided to improve the uniformity of the light emitted from it. Such a diffusion layer can be provided near the light emitting surface of the light guide 100 and can be attached to the light guide using an additional adhesive layer 124 as a selection means. Exemplary diffusing layers include, but are not limited to, textured, roughened or particle filled to form light diffusing features on the order of wavelengths of light to be diffused or less, eg, submicron sized diffusing features. Can include polymer sheets such as acrylic sheets, polycarbonate sheets and polyethylene terephthalate sheets. An exemplary particle-filled polymer sheet can include titania or alumina, for example, having a particle size of about 500 nm or less. Textured polymer sheets are commercially available from Luminit™. In certain embodiments, a color conversion medium, a light scattering feature and/or a reflective material traverses the light emitting surface of the light guide, for example, as shown in FIGS. 14A-14C or 16A-16C. It can be arranged on the main surface of the light guide and/or the transparent substrate in a pattern capable of forming a sufficiently uniform light color and/or light intensity. In such cases, the diffusing layer can be eliminated from the optical assembly as it further reduces the total thickness of the optical assembly.

As discussed above, the optical assemblies disclosed herein have a thin film nature as compared to prior art optical assemblies due to the at least partial absence of an air gap between the light source and the light guide. Has been improved. Currently commercially available optical assemblies can have a total thickness of greater than 15 mm. In contrast, the optical assemblies disclosed herein can have a total thickness of less than about 10 mm. For example, an exemplary optical assembly with a diffusing layer can have a thickness of less than about 10 mm, and an exemplary optical assembly without a diffusing layer can have a thickness of less than about 5 mm. The thickness of the optical assembly with or without the diffusing layer, in some embodiments, is in the range of about 4 mm to about 10 mm, including all of the range and subranges therein, eg, about 4. It can range from 5 mm to about 9 mm, about 5 mm to about 8 mm, or about 6 mm to about 7 mm.

FIG. 18 shows a plan view of an exemplary device that includes an array of light guides 100 having a light coupling surface 105 that is optically coupled to an array of light sources 111. In the illustrated embodiment, the light source 111 is arranged so as to surround the circumference of each light guide body 100. Although eight light sources 111 are shown per light guide 100 in the array, it should be understood that the number is arbitrary and that any number of light sources can be used. The position of the light source(s) 111 may also be different from that shown in FIG. 18, without limitation, if desired. The patterned color conversion medium (not shown) can also be adjusted as desired to suit the number and location of the light source(s) 111(s).

The light source(s) 111 can also be located in a central position, as shown in the non-limiting embodiment of FIG. In such a configuration, the light coupling surface 105 ″ may have a dome-like shape located in the central region of the light guide 100, for example, a conformal spiral curvature forms a dome-like shape. It can rotate about the center axis normal to the lower light source 111. The dome-shaped light coupling surface 105'' reflects and guides the light from the light source(s) 111 until it contacts the color conversion medium and is converted and emitted from the light guide. The light can be redirected back into the light body 100. Also, although four light sources 111 are shown per light guide 100 in the array, it should be understood that the number is arbitrary and that any number of light sources can be used. The position of the light source(s) 111 may also be different from that shown in FIG. 19 without limitation, as desired. The patterned color conversion medium (not shown) can also be adjusted as desired to suit the number and location of the light source(s) 111(s).

It will be appreciated that the various disclosed embodiments can include the particular features, elements or steps described in connection with the particular embodiment. Also, although described in connection with a particular embodiment, various combinations or permutations in which the particular feature, element or step is not described are interchangeable or combinable with the alternative embodiment. It will also be understood.

Also, as used herein, the term "said," "one," or "a" means "at least one," unless explicitly indicated otherwise. It should also be understood that it should not be limited to "only". Thus, for example, the designation "one cavity" includes examples having one such "cavity" or more than one such "cavity" unless the context clearly dictates otherwise. Similarly, "plurality" or "array" is intended to indicate two or more, so that "cavity array" or "plurality of cavities" refers to two or more such cavities.

Ranges can be expressed herein as from one particular "approximate" value, and/or to another "approximate" value. When expressing such a range, each example includes from one particular value and/or to another particular value. Similarly, where the prefix "about" is used to describe a value as an approximation, it should be understood that the particular value forms another aspect. Furthermore, it should also be understood that the endpoints of each of the ranges are significant both in relation to the endpoint on the other side, and independently of the endpoint on the other side.

All numerical values expressed herein are to be construed as including "about" whether stated or not, unless expressly indicated to the contrary. However, it should be understood that each numerical value referred to can also be considered strictly, regardless of whether or not the value is expressed as "about". Thus, “dimensions less than 10 mm” and “dimensions less than about 10 mm” both include embodiments “dimensions less than about 10 mm” and embodiments “dimensions less than 10 mm”.

Unless explicitly stated otherwise, none of the methods described herein are intended to be construed as requiring execution of the steps in a particular order. Thus, it is expressly stated that the method claims do not actually refer to the order in which the steps are followed, or that each step in the claims or the description should be limited to a particular order. No indication of any particular order is intended at all.

Various features, elements or steps of particular embodiments have been disclosed using the transitional phrase “comprising”, which may consist of the transitional phrases “consisting of” or “consisting essentially of”. It is to be understood that the phrase “A” is used to suggest an alternative embodiment including the various features, elements or steps that can be described. Thus, for example, alternative embodiments suggested for methods involving A+B+C include method embodiments consisting of A+B+C and method embodiments consisting essentially of A+B+C.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and perspective of the disclosure. Combinations, subcombinations and variations of modifications of the embodiments of the present disclosure that incorporate the spirit and substance of the present disclosure are conceivable to those skilled in the art, and therefore the present disclosure includes the scope of the appended claims and It should be construed as including all that are applicable in terms of their equivalents.

The following examples are intended as non-limiting and illustrative examples in terms of the present invention as defined in the claims.

Example 1
A light guide plate with two light-coupling edges with an equiangular spiral curvature (see, eg, FIGS. 2A-2C) at a constant angle of incidence θ _i =42°, a PMMA with a refractive index n=1.5. Manufactured from. The light guide plate has a width of 38.5 mm, a length of 45 mm and a thickness of 4.608 mm. The light guide plate was used as two optical assemblies to form a first optical assembly coupled to four LEDs and a second optical assembly coupled to six LEDs. Each LED was soldered to a PCB and supplied with an operating current of 200 mA from a power source of Keithley. The optical assembly has a total thickness of 5.3 mm.

An Ocean Optic spectrometer was used to measure the spectrum of the light emitted by the optical assembly. A Chroma Meter (CS160) from Konica Minolta was used to measure the color and brightness of the light emitted by the optical assembly. The optical assembly was photographed and inspected using a digital camera with a zoom lens. The light emission intensity profiles of the first optical assembly (4 LEDs, 0.0039 second exposure) measured along rows and columns near the center of the light guide are shown in Figures 20A and 20B, respectively. In a separate experiment, 7400 nits were produced at the center of the lightguide when four LEDs were illuminated at an operating current of 100 mA. The light emission intensity profile of the second optical assembly (6 LEDs, 0.01013 second exposure) measured along a row near the center of the light guide is shown in FIG. 20C. A 16.5 x 45 mm illuminated area (43% of total area) was created in the center of the lightguide with the designed light coupling edge.

The first optical assembly (4 LEDs) was incorporated into a stack that included a reflective film and a Nanoco Corporation QD film located on the bottom surface (first major surface) of the light guide plate. Patterns designed to improve the brightness and color uniformity of the light emitted from the light guide were created on the QD film using mechanical means. In some cases, the diffuser film is placed on the top surface (second major surface) of the light guide plate, thus increasing the thickness of the stack to 9.7 mm. FIG. 6 shows the light emission intensity profiles of an optical assembly (4 LEDs, 0.0039 sec exposure) including a diffusion film and an unpatterned QD film, measured along rows and columns near the center of the light guide, respectively. 21A and 21B. FIG. 21C shows a light emission intensity profile of an optical assembly (4 LEDs, 0.01 second exposure) containing a patterned QD film without a diffusion film, measured along a row near the center of the light guide, FIG. 21C. Shown in. The light emission intensity profile of an optical assembly (4 LEDs, 0.04 second exposure) containing a patterned QD film and a diffusion film, measured along a row near the center of the light guide, is shown in FIG. 21D. Laminates containing diffuser films produce less radiation, probably due to imperfections in manufacturing, but the uniformity of intensity distribution is improved over laminates without such films. Even with a diffusion film, such laminates have a reduced thickness compared to currently commercially available LCD laminates having a total thickness of 15 mm or greater.

Example 2
The optical assembly 300 shown in FIG. 22 was designed as an exemplary embodiment of an assembly having a total thickness of less than 5 mm. The light guide plate 100A (see FIGS. 2A-2C) was composed of PMMA with a refractive index n=1.5. The light guide plate has a width of 50 mm, a length of 60 mm and a thickness of 4.035 mm. The light coupling edge 105 is truncated so that a straight edge portion and a profile portion with a constant incident angle θ _i =42° are formed (see FIG. 9). The light L is emitted from the second main surface 102 of the light guide plate 100A.

The design here includes a transparent substrate 130 with a refractive index n=1.5. The transparent substrate has a width of 50 mm, a length of 60 mm and a thickness of 0.3 mm. The main surface of the transparent substrate is masked to form a QD( For example, it is patterned so as to have a 3M QDEF).

Four light sources 111 (blue LEDs from Flip Chip Opto, 450 nm, >0.42 W, 0.5 A) are mounted on a FR4 PCB 122 having a thickness of 0.508 mm. The LED has a length and width of 0.875 mm and a thickness of 0.145 mm. The spatial distribution of LEDs is almost evenly diffused. A current C can be applied to the electrical circuitry of the PCB 122 to control the light output of the LED. An LED can generate a light output equivalent to 1 W with a high diode current. Heat H from the LEDs and/or color conversion media can be conducted through a metal layer (not shown) on the bottom surface of PCB 122. The PCB 122 has metal wires and pads for connection to the LEDs, and thermal vias that transport heat from the top surface to the bottom surface of the PCB.

The light guide plate 100A is applied to the transparent substrate 130 using an optically transparent index-adapted adhesive layer 124A (Silicone adhesive from Dow Coming, n=1.5) having a thickness of 0.025 mm. It is installed. The transparent substrate 130 is attached to the PCB 122 using a thermally conductive adhesive layer 124B from Dow Coming. An aperture 140 corresponding to the light source 111 is provided on each of the adhesive layers 124A and 124B and the transparent substrate 130. The apertures 140 have a pitch of 25 mm and are spaced 12.5 mm from the substrate edge. The total thickness of the optical assembly is 4.92 mm. For example, by using smaller LEDs, such as Lumileds diodes (455 nm, >0.65 W, 0.5 A), by patterning the color conversion medium and reflective material directly into the lightguide, and/or more. Thinner assemblies can also be obtained by using a lightguide with a high index of refraction, eg n>1.7.

Example 3
The optical assembly 300 described in Example 2 was assembled using Lighttools ray propagation software with the following assumptions: (1) The space between the top surface of the LED and the bottom surface of the light guide was filled with an exponential adaptation layer. (2) The refractive index of the light guide, the transparent substrate and the index adaptation layer is n=1.5; (3) the upper surface of the transparent substrate is optically coupled to the lower surface of the light guide; 4) The quantum dots of the transparent substrate form a simple scattering surface with uniform diffusion properties; (5) the reflective layer has a broadband mirror surface; (6) all other surfaces are of high quality. It is an optical surface; and (7) except for the lower surface (second main surface) of the light guide, all other light guide surfaces are considered to be in contact with air. The LED surface was set as the illuminating surface and the receiver was placed in the light output plane parallel to the first main surface (light emitting surface) of the light guide and just outside this surface. Lighting properties were calculated using Lighttools at the light output plane.

An optical assembly containing a glass substrate uniformly coated with QD was used for baseline calculation. The output illumination profile (W/mm ² ) of such an optical assembly is shown in Figure 23A. The illumination profile shows four areas of high intensity corresponding to the four LEDs. Irradiation uniformity, measured by the ratio of the standard deviation to the average, is 41%. Without wishing to be bound by theory, it is believed that the illumination uniformity of the optical assembly can be improved by providing the optical assembly with a diffusing layer, although such a layer increases the overall thickness of the device. However, even with such a diffusion layer, the total thickness of the assembly can still be less than 10 mm, an improvement over currently available assemblies with thicknesses greater than 15 mm.

The optical assembly 300 prepared in Example 2 and including the patterned transparent substrate 130 was also inspected using Lighttools software. The output irradiation profile (W/mm ² ) is shown in FIG. 23B. The irradiation profile is much more uniform than the baseline profile shown in FIG. 23A. Irradiation uniformity, measured by the ratio of the standard deviation to the mean, was 18.5%, a significant advance over baseline assembly and currently available assemblies.

The brightness measured at the light output plane was calculated to be above 50,000 nit for a total input power of 4 W from the LED. The brightness can be increased by adding more LEDs along the light-coupling surface(s) if desired. Considering the QD as a scattering layer that does not perform color conversion, 61% of the LED output is the light output plane, 29% of the LED output is the optical coupling edge (50 mm width), and 10% of the LED output is non- Emitted at the light-coupling edge (60 mm length). Without wishing to be bound by theory, it is believed that more power can be provided to the light output plane by applying a reflective coating to the non-light coupling edges.

The preferred embodiments of the present invention will be described below item by item.

Embodiment 1
A light guide,
At least one light emitting surface and at least one light coupling surface, at least a portion of said at least one light coupling surface having a conformal helix curvature,
Light guide.

Embodiment 2
The light guide is
The first major surface,
A light guide plate having an opposite second major surface and at least one edge surface, the at least one edge surface including the light coupling surface;
The light guide according to the first embodiment.

Embodiment 3
The light guide is
The first major surface,
A light guide disk having an opposite second major surface and an edge surface, the edge surface including the light coupling surface.
The light guide according to the first embodiment.

Embodiment 4
The second major surface includes the light emitting surface,
The light guide according to the second or third embodiment.

Embodiment 5
The light guide further comprises at least one of a color conversion medium, a light scattering feature and a reflective material patterned on the first major surface.
The light guide according to the fourth embodiment.

Embodiment 6
A reflective layer is disposed on the first major surface and at least partially encapsulates the color conversion medium patterned on the first major surface;
The light guide according to the fourth embodiment.

Embodiment 7
The light guide is
Inner wall surface,
An outer wall surface and a light guide annulus having at least one edge surface, the at least one edge surface including the light coupling surface.
The light guide according to the first embodiment.

Embodiment 8
The outer wall surface includes the light emitting surface,
The light guide according to the seventh embodiment.

Embodiment 9
The light guide annulus includes a hollow cylinder,
The light guide according to the seventh embodiment.

Embodiment 10
The light guide is
The first end face,
The second end face,
An outer wall surface, and a light guide rod having an edge surface, the edge surface including the optical coupling surface,
The light guide according to the first embodiment.

Embodiment 11
At least one of the first end surface, the second end surface and the outer wall surface includes the light emitting surface,
The light guide according to embodiment 10.

Embodiment 12
An optical assembly including at least one light source optically coupled to a light guide according to any one of embodiments 1-11.

Embodiment 13
The at least one light source is bonded to a printed circuit board,
The optical assembly according to embodiment 12.

Embodiment 14
The optical assembly further includes a transparent substrate having a major surface patterned with at least one of a color conversion medium, a light scattering feature and a reflective material,
The optical assembly according to embodiment 12 or 13.

Embodiment 15
A color conversion medium is patterned on the major surface and a reflective layer at least partially encapsulates the color conversion medium;
The optical assembly according to embodiment 13.

Embodiment 16
The optical assembly further includes a diffusing layer disposed near the at least one light emitting surface of the light guide.
16. The optical assembly according to any one of Embodiments 12 to 15.

Embodiment 17
The optical assembly includes a stack having a total thickness of less than about 10 mm.
The optical assembly of any one of embodiments 12-16.

Embodiment 18.
The laminate has a total thickness of less than about 5 mm,
The optical assembly according to embodiment 17.

Embodiment 19.
The light guide and the transparent substrate include glass, plastic or a combination thereof.
The optical assembly according to embodiment 12.

Embodiment 20
A display device, a lighting device, or an electronic device, including the optical assembly according to any one of Embodiments 12 to 19.

Embodiment 21
The device comprises an array of optical assemblies,
The apparatus according to embodiment 20.

Claims (15)

A light guide,
At least one light emitting surface and at least one light coupling surface, at least a portion of said at least one light coupling surface having a conformal helix curvature,
Light guide. The light guide is
The first major surface,
A light guide plate having an opposite second major surface and at least one edge surface, the at least one edge surface including the light coupling surface;
The light guide according to claim 1. The light guide is
The first major surface,
A light guide disk having an opposite second major surface and an edge surface, the edge surface including the light coupling surface.
The light guide according to claim 1. The second major surface includes the light emitting surface,
The light guide according to claim 2 or 3. The light guide further comprises at least one of a color conversion medium, a light scattering feature and a reflective material patterned on the first major surface.
The light guide according to any one of claims 1 to 4. A reflective layer is disposed on the first major surface and at least partially encapsulates the color conversion medium patterned on the first major surface;
The light guide according to claim 4. The light guide is
Inner wall surface,
An outer wall surface and a light guide annulus having at least one edge surface, the at least one edge surface including the light coupling surface.
The light guide according to claim 1. The light guide is
The first end face,
The second end face,
An outer wall surface, and a light guide rod having an edge surface, the edge surface including the optical coupling surface,
The light guide according to claim 1. At least one of the first end surface, the second end surface and the outer wall surface includes the light emitting surface,
The light guide according to claim 8. An optical assembly including at least one light source optically coupled to the light guide of claim 1. The at least one light source is bonded to a printed circuit board,
The optical assembly according to claim 10. The optical assembly further includes a transparent substrate having a major surface patterned with at least one of a color conversion medium, a light scattering feature and a reflective material,
The optical assembly according to claim 10 or 11. A color conversion medium is patterned on the major surface and a reflective layer at least partially encapsulates the color conversion medium;
The optical assembly according to claim 12. The optical assembly further includes a diffusing layer disposed near the at least one light emitting surface of the light guide.
An optical assembly according to any one of claims 10 to 13. A display device, a lighting device, or an electronic device, comprising the optical assembly according to any one of claims 10 to 14.

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