Optical constructs, backlight, and display system

Abstract

The backlight source includes an extended illumination source configured to emit light. The emitted light includes an emission spectrum comprising corresponding non-overlapping first emission light-wavelength (FWHM) and second emission light-wavelength (FWHM). The backlight source includes one or more light conversion films disposed on the extended emission surface, the one or more light conversion films comprising green and red emission spectra having corresponding non-overlapping green and red emission light-wavelength (FWHM) light-wavelength (FWHM). The backlight source includes optical films disposed on the one or more light conversion films opposite to the extended emission surface. For substantially collimated incident light, a first incident angle of less than about 10 degrees, and for each of mutually orthogonal in-plane first and second polarization states, the plurality of polymer layers have an average optical transmittance of less than about 10% for the wavelength across the first emission FWHM, and an average optical transmittance of greater than about 60% and less than about 95% for each of the second FWHM, the green FWHM, and the red FWHM.

Description

Technical Field

[0001] This disclosure relates to a backlight and a display system including the backlight. This disclosure also relates to optical structures used in the backlight. Background Technology

[0002] Typically, a backlight illuminates a display panel configured to display images on a display system. Currently, display panels in high-end display systems incorporate quantum dot films and blue light-emitting diodes (LEDs) in their backlights. Quantum dot films enhance the color gamut of the display system and provide more vibrant colors. However, the quantum dot materials used in quantum dot films can be expensive, and therefore, including quantum dot films in the backlight may be an obstacle to their adoption in the mainstream of display systems. Summary of the Invention

[0003] In a first aspect, this disclosure provides a backlight source for illuminating a display panel configured to display an image. The backlight source includes an extended illumination source comprising one or more light sources and an extended emitting surface. The extended illumination source is configured to emit light toward the display panel through the extended emitting surface. The emitted light includes an emission spectrum comprising a first emission peak and a second emission peak at corresponding first and second emission peak wavelengths, and corresponding non-overlapping first and second full width at half maximum (FWHM) and second full width at half maximum (FWHM). The backlight source also includes one or more light conversion films disposed on the extended emitting surface of the extended illumination source and comprising a green emission spectrum and a red emission spectrum comprising corresponding green and red peaks at corresponding green and red peak wavelengths, and corresponding non-overlapping green and red FWHMs. The green FWHM is disposed between the second FWHM and the red FWHM. The one or more light conversion films are configured to receive emitted light through an extended emitting surface and convert at least a portion of the received emitted light into green and red light having corresponding green and red wavelengths disposed in respective green and red light FWHMs and red light FWHMs. The backlight also includes an optical film disposed on the one or more light conversion films opposite to the extended emitting surface and comprising a plurality of polymer layers totaling at least 10. Each of these polymer layers has an average thickness of less than about 500 nanometers (nm). For substantially collimated incident light, a first incident angle of less than about 10 degrees, and for each of mutually orthogonal in-plane first and second polarization states, the plurality of polymer layers have an average optical transmittance of less than about 10% for the wavelength across the first emitting FWHM, and an average optical transmittance of greater than about 60% and less than about 95% for each of the second FWHM, the green FWHM, and the red FWHM.

[0004] In a second aspect, this disclosure provides a display system. The display system includes a display panel disposed on a backlight source of the first aspect. The display panel is configured to receive light emitted through an extended emitting surface and to display an image. An optical film is disposed between the display panel and one or more light conversion films.

[0005] In a third aspect, this disclosure provides an optical construct for use in a backlight of a display system. The backlight is configured to provide illumination to a display panel of the display system configured to display an image. The optical construct includes one or more light conversion films and an optical film disposed on the one or more light conversion films. The optical film includes a plurality of polymer layers totaling at least 10. Each of these polymer layers has an average thickness of less than about 500 nm. The optical construct also includes an adhesive layer for bonding the optical film to the one or more light conversion films. For substantially collimated incident light, a first incident angle less than about 10 degrees, a second incident angle not less than about 30 degrees, a violet wavelength range extending from about 390 nm to about 410 nm, a blue wavelength range extending from about 440 nm to about 460 nm, a green wavelength range extending from about 515 nm to about 540 nm, and a red wavelength range extending from about 600 nm to about 670 nm, and for each of mutually orthogonal in-plane first and second polarization states: one or more light conversion films convert at least a portion of the incident light having wavelengths in the violet wavelength range into light having wavelengths in the corresponding green wavelength range. The device has green and red light wavelengths in the long range and red light wavelength range, and has an optical transmittance greater than about 50% for each of the blue light wavelength range, green light wavelength range, and red light wavelength range; and the multiple polymer layers have an average optical transmittance of less than about 10% for the violet light wavelength range and the first incident angle, an average optical transmittance of greater than about 20% for the violet light wavelength range and the second incident angle, and an average optical transmittance of greater than about 60% and less than about 95% for each of the blue light wavelength range, green light wavelength range, and red light wavelength range, and for each of the first incident angle and the second incident angle.

[0006] Details of one or more examples of this disclosure are set forth in the accompanying drawings and the following description. Other features, objects, and advantages of this disclosure will become apparent from the description, the drawings, and the claims. Attached Figure Description

[0007] The exemplary embodiments disclosed herein can be more fully understood in light of the following detailed description taken in conjunction with the accompanying drawings. The drawings are not necessarily drawn to scale. Similar numbers used in the drawings refer to similar parts. However, it should be understood that the use of numbers to refer to parts in a given drawing is not intended to limit parts labeled with the same numbers in another drawing.

[0008] Figure 1 A schematic cross-sectional view of a display system according to an embodiment of the present disclosure is shown;

[0009] Figure 2A A detailed schematic cross-sectional view of the optical film of a display system according to an embodiment of the present disclosure is shown;

[0010] Figure 2B This is a detailed schematic cross-sectional view of the reflective polarizer of a display system according to an embodiment of the present disclosure;

[0011] Figure 3 A graph depicting the relationship between the optical transmittance of the optical film and wavelength for substantially collimated incident light incident at different incident angles, according to an embodiment of the present disclosure, is shown; and

[0012] Figure 4 A graph depicting the relationship between the optical reflectivity and wavelength of a back reflector according to an embodiment of the present disclosure is shown. Detailed Implementation

[0013] In the following description, reference is made to the accompanying drawings, which form a part thereof, and various embodiments are illustrated therein. It should be understood that other embodiments may be conceived and made without departing from the scope or spirit of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0014] In the following disclosure, the following definitions are used.

[0015] As used herein, all numbers should be considered as being modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “a or more” are used interchangeably.

[0016] As used herein, as a modifier of a characteristic or attribute, unless otherwise specifically defined, the term “approximately” means that the characteristic or attribute will be easily identifiable by a person skilled in the art without requiring absolute precision or a perfect match (e.g., within + / - 20% for quantifiable characteristics).

[0017] Unless otherwise specifically defined, the term “substantially” means a high degree of approximation (e.g., within + / -10% for quantifiable properties), but also does not require absolute precision or a perfect match.

[0018] Unless otherwise specifically defined, the term “approximately” means a high degree of approximation (e.g., within + / -5% for quantifiable properties), but also does not require absolute precision or a perfect match.

[0019] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting the scope of this disclosure. Throughout the embodiments of this disclosure, the terms “first” and “second” are interchangeable when used in conjunction with a feature or element.

[0020] As used in this article, "at least one of A and B" should be understood as meaning "only A, only B, or both A and B".

[0021] As used herein, the term "layer" generally refers to a thickness of material having a relatively uniform chemical composition within a membrane. A layer can be any type of material, including polymers, cellulose, metals, or blends thereof. A given polymer layer may comprise a single polymer type or a blend of polymers and may include additives. A given layer may be combined with or bonded to other layers to form a membrane. A layer may be partially continuous or completely continuous compared to adjacent layers or membranes. A given layer may be partially or completely co-extended with adjacent layers. A layer may contain sublayers.

[0022] Typically, a backlight illuminates a display panel configured to display images on a conventional display system. Currently, display panels in high-end display systems incorporate quantum dot films and blue light-emitting diodes (LEDs) in their backlights. Quantum dot films enhance the color gamut of the display system and provide more vibrant colors. However, the quantum dot materials used in quantum dot films can be expensive, and therefore, including quantum dot films in backlights may be an obstacle to their adoption in the mainstream of display systems.

[0023] This disclosure relates to a backlight, a display system including the backlight, and an optical structure used in the backlight.

[0024] A backlight provides illumination to a display panel configured to display an image. The backlight includes an extended illumination source comprising one or more light sources and an extended emitting surface. The extended illumination source is configured to emit light toward the display panel through the extended emitting surface. The emitted light includes an emission spectrum comprising a first emission peak and a second emission peak at corresponding first and second emission peak wavelengths, and corresponding non-overlapping first and second full width at half maximum (FWHM) and second full width at half maximum (FWHM). The backlight also includes one or more light conversion films disposed on the extended emitting surface of the extended illumination source and comprising a green emission spectrum and a red emission spectrum comprising corresponding green and red peaks at corresponding green and red peak wavelengths, and corresponding non-overlapping green and red FWHMs. The green FWHM is disposed between the second FWHM and the red FWHM. The one or more light conversion films are configured to receive emitted light through an extended emitting surface and convert at least a portion of the received emitted light into green and red light having corresponding green and red wavelengths disposed in respective green and red light FWHMs and red light FWHMs. The backlight also includes an optical film disposed on the one or more light conversion films opposite to the extended emitting surface and comprising a plurality of polymer layers totaling at least 10. Each of these polymer layers has an average thickness of less than about 500 nanometers (nm). For substantially collimated incident light, a first incident angle of less than about 10 degrees, and for each of mutually orthogonal in-plane first and second polarization states, the plurality of polymer layers have an average optical transmittance of less than about 10% for the wavelength across the first emitting FWHM, and an average optical transmittance of greater than about 60% and less than about 95% for each of the second FWHM, the green FWHM, and the red FWHM.

[0025] The emitted light can include blue light as well as violet light other than blue light. Therefore, the emission wavelength range (FWHM) of the emission spectrum can lie within both the violet and blue light wavelength ranges. One or more light conversion films can have better efficiency in converting violet light within the violet wavelength range into green and red light compared to converting blue light within the blue light wavelength range into green and red light. Specifically, one or more light conversion films can contain quantum dot materials. Quantum dot materials can have high absorption rates for violet light within the violet wavelength range. Therefore, the amount of quantum dot material required to convert violet light within the violet wavelength range can be substantially low. Thus, an extended illumination source that emits violet light in addition to blue light can reduce the amount of quantum dot material required in one or more light conversion films to convert emitted light, including both blue and violet light, into green and red light. This can reduce the cost of one or more light conversion films in the backlight. Furthermore, an optical film disposed on one or more light conversion films can reduce the amount of violet light within the violet wavelength range reaching the viewer's eyes. Specifically, the optical film can reflect a portion of violet light in the violet wavelength range that is not absorbed by the quantum dot material to reduce the amount of violet light in the violet wavelength range reaching the viewer's eye.

[0026] Therefore, the backlight of this disclosure can reduce the use of quantum dot material in one or more light conversion films in order to reduce the cost of the display system, while preventing violet light in the violet wavelength range from reaching the viewer's eyes.

[0027] Now refer to the attached diagram, Figure 1 This is a schematic exploded cross-sectional view of a display system 300 according to one embodiment of the present disclosure.

[0028] The display system 300 defines mutually orthogonal x-axis, y-axis, and z-axis. The x-axis and y-axis are in-plane axes of the display system 300, while the z-axis is a transverse axis set along the thickness of the display system 300. In other words, the x-axis and y-axis are set along the plane of the display system 300, while the z-axis is perpendicular to the plane of the display system 300.

[0029] Display system 300 includes a display panel 40. Display panel 40 is configured to display an image 42. Display panel 40 is disposed on a backlight 200. In some embodiments, display system 300 includes a backlight 200. Backlight 200 provides illumination 41 to display panel 40. Specifically, backlight 200 is configured to provide illumination 41 to display panel 40 of display system 300 configured to display image 42. In other words, display panel 40 is configured to receive illumination 41 from backlight 200 and display image 42. In some embodiments, display panel 40 includes a liquid crystal display (LCD) panel.

[0030] The backlight 200 includes an extended illumination source 21. The extended illumination source 21 includes one or more light sources 20 and an extended emitting surface 22. The extended illumination source 21 is configured to emit light 23 toward the display panel 40 through the extended emitting surface 22. In some embodiments, the display panel 40 is configured to receive the light 23 emitted through the extended emitting surface 22 and display an image 42. In some embodiments, the light 23 can be interchangeably referred to as "emitted light 23".

[0031] In some embodiments, one or more light sources 20 include at least a first light source 20 and at least a second light source 20. At least the first light source 20 is configured to emit a first emitted light 23v, and at least the second light source 20 is configured to emit a second emitted light 23b.

[0032] Therefore, in some embodiments, the emitted light 23 from one or more light sources 20 includes a first emitted light 23v emitted from at least a first light source 20 of the one or more light sources 20 and a second emitted light 23b emitted from at least a second light source of the one or more light sources 20. Thus, the emitted light 23 may be referred to as "emitted light 23v, 23b".

[0033] In some embodiments, at least the first light source 20 is a violet light source, and the first emitted light 23v is violet light. Therefore, the first emitted light 23v can be interchangeably referred to as "violet light 23v". In some embodiments, at least the second light source 20 is a blue light source, and the second emitted light 23b is blue light. Therefore, the second emitted light 23b can be interchangeably referred to as "blue light 23b". In some embodiments, the violet light 23v has a violet wavelength within the violet wavelength range. Similarly, the blue light 23b has a blue wavelength within the blue wavelength range. In some embodiments, the violet wavelength range extends from about 390 nanometers (nm) to about 410 nm, and the blue wavelength range extends from about 440 nm to about 460 nm.

[0034] In some embodiments, the extended illumination source 21 further includes a light guide 24 for receiving light 24a from one or more light sources 20 and propagating the received light 24a along its length and width. In some embodiments, the length of the light guide 24 extends substantially along the x-axis. In some embodiments, the width of the light guide 24 extends substantially along the y-axis.

[0035] The received light 24a propagates in the optical guide 24 as propagating light 24b. Furthermore, the propagating light 24b exits the optical guide 24 as exiting light 24c through the exiting surface 25. In some embodiments, the exiting surface 25 extends substantially together with the extended emitting surface 22 in both length and width. In some embodiments, the length of the exiting surface 25 extends substantially along the x-axis. In some embodiments, the width of the exiting surface 25 extends substantially along the y-axis.

[0036] In some embodiments, the emitted light 24c exits the extended illumination source 21 as emitted light 23v, 23b via the extended emitting surface 22. In some embodiments, the emitting surface 25 of the light guide 24 includes the extended emitting surface 22.

[0037] In some embodiments, the extended illumination source 21 also includes a back reflector 27. In some embodiments, the back reflector 27 extends substantially together with the extended emitting surface 22 in both length and width. The back reflector 27 may be configured to reflect any light leaving the light guide 24 and reaching the back reflector 27 back towards the light guide 24. The back reflector 27 may include a reflective surface (e.g., a metallic surface) or may have a multi-layered configuration. In some embodiments, the light guide 24 is disposed between the extended emitting surface 22 and the back reflector 27.

[0038] In some embodiments, the back reflector 27 is spaced apart from the extended emitting surface 22. In some embodiments, an optical cavity 28 is defined between the extended emitting surface 22 and the back reflector 27.

[0039] In some embodiments, one or more light sources 20 are disposed near one or more edge surfaces 26 of the light guide 24. In some embodiments, one or more light sources 20 are disposed within an optical cavity 28.

[0040] The backlight 200 also includes one or more light conversion films 15 disposed on the extended emitting surface 22 of the extended illumination source 21. In some embodiments, the one or more light conversion films 15 comprise one or more of phosphors, fluorescent dyes, and quantum dots.

[0041] One or more light conversion films 15 are configured to receive light 23v, 23b emitted through the extended emitting surface 22. The one or more light conversion films 15 are configured to convert at least a portion of the received emitted light 23v, 23b into green light 10g and red light 10r. The green light 10g and red light 10r have corresponding green and red wavelengths.

[0042] exist Figure 1In the illustrated embodiments, one or more light conversion films 15 include a green light conversion film 15g and a red light conversion film 15r. In some cases, "one or more light conversion films 15" can be interchangeably referred to as "light conversion films 15g, 15r".

[0043] In some embodiments, the green light conversion film 15g is configured to receive light 23 emitted through the extended emitting surface 22 and convert at least a portion of the received emitted light 23 into green light 10g having a green wavelength. Similarly, the red light conversion film 15r is configured to receive light 23 emitted through the extended emitting surface 22 and convert at least a portion of the received emitted light 23 into red light 10r having a red wavelength.

[0044] The backlight 200 also includes an optical film 30. The optical film 30 is disposed on one or more light conversion films 15, opposite to the extended emitting surface 22. Furthermore, in Figure 1 In the illustrated embodiments, the optical film 30 is disposed between the display panel 40 and one or more light conversion films 15. In some embodiments, the optical film 30 extends substantially together with the display panel 40 and the one or more light conversion films 15 in both length and width.

[0045] In some embodiments, the backlight 200 further includes an adhesive layer 70 that bonds the optical film 30 to one or more light conversion films 15. The adhesive layer 70 can be interchangeably referred to as the "first adhesive layer 70". Thus, in other words, the optical film 30 is bonded to one or more light conversion films 15 via the first adhesive layer 70.

[0046] In some embodiments, the backlight 200 further includes at least one barrier layer (not shown) disposed on one or more light conversion films 15. In some embodiments, the at least one barrier layer comprises a pair of barrier layers, and the one or more light conversion films 15 are disposed between the pair of barrier layers. In some embodiments, the at least one barrier layer at least partially or completely encapsulates one or more light conversion films 15. In some embodiments, the at least one barrier layer also at least partially or completely encapsulates the first adhesive layer 70.

[0047] In some embodiments, at least one barrier layer may be attached to one or more light conversion films 15 via a chemical process. In some embodiments, at least one barrier layer may be attached to one or more light conversion films 15 via crosslinking through an ultraviolet (UV) process or a thermosetting process. In some embodiments, at least one barrier layer is a moisture barrier layer. At least one barrier layer may reduce moisture permeation to one or more light conversion films 15. At least one barrier layer may have a moisture content of less than about 1 gm / m² at 50 degrees Celsius (°C), for example, as measured using Mocon. 2 / day, less than approximately 0.01 gm / m2 / day or less than about 0.001 gm / m 2 Moisture transmittance per day (MVTR).

[0048] In some embodiments, one or more light conversion films 15, optical films 30, and first adhesive layers 70 may be collectively referred to as such. Figure 1 The optical structure 400 is indicated in the document. The optical structure 400 is used in the backlight 200 of the display system 300.

[0049] In some embodiments, the backlight 200 further includes an optical diffuser 80 disposed on the optical film 30 opposite to one or more light conversion films 15. In some embodiments, the optical film 30 is bonded to the optical diffuser 80 via a second adhesive layer 71.

[0050] In some embodiments, the backlight 200 further includes a first prism film 90. The first prism film 90 is disposed on the optical film 30 opposite to one or more light conversion films 15. The first prism film 90 includes a plurality of first prisms 91. In some embodiments, the plurality of first prisms 91 extend along substantially the same first longitudinal direction. In some embodiments, the first longitudinal direction extends substantially along the y-axis.

[0051] In some embodiments, the backlight 200 further includes a second prism film 92 disposed on the first prism film 90 opposite to the optical film 30. The second prism film 92 includes a plurality of second prisms 93. The plurality of second prisms 93 extend along a substantially identical second longitudinal direction different from the first longitudinal direction. In some embodiments, the second longitudinal direction extends substantially along the x-axis.

[0052] In some embodiments, the optical diffuser 80 is disposed between the first prism film 90 and the optical film 30. In some embodiments, the optical diffuser 80 is bonded to the first prism film 90 via a third adhesive layer 72.

[0053] exist Figure 1 In the illustrated embodiments, the backlight 200 further includes a reflective polarizer 100 disposed on the optical film 30 opposite to one or more light conversion films 15. In some embodiments, the reflective polarizer 100 is bonded to the display panel 40 via a fourth adhesive layer 73. In some embodiments, each of the first adhesive layer 70, the second adhesive layer 71, the third adhesive layer 72, and the fourth adhesive layer 73 may comprise an optically clear adhesive (OCA).

[0054] Figure 2A This is a detailed schematic cross-sectional view of the optical film 30 according to an embodiment of the present disclosure.

[0055] The optical film 30 includes a plurality of polymer layers 43. The total number of the plurality of polymer layers 43 is at least 10. In some embodiments, the total number of the plurality of polymer layers 43 is at least 20, at least 50, at least 75, at least 100, at least 150, at least 200, at least 250, or at least 300.

[0056] Each polymer layer in polymer layer 43 has an average thickness t of less than about 500 nm. As used herein, the term "average thickness t" refers to the average thickness measured at multiple points across a plane (i.e., the xy plane) spanning each polymer layer in the plurality of polymer layers 43. In some embodiments, each polymer layer in polymer layer 43 has an average thickness t of less than about 400 nm, less than about 300 nm, or less than about 200 nm.

[0057] In some embodiments, the plurality of polymer layers 43 include a plurality of alternating first polymer layers 31 and second polymer layers 32. The plurality of alternating first polymer layers 31 and second polymer layers 32 are stacked along the thickness direction of the optical film 30. In some embodiments, the thickness direction extends substantially along the z-axis.

[0058] In some embodiments, the optical film 30 further includes at least one surface layer 33 disposed on a plurality of polymer layers 43. In some embodiments, the at least one surface layer 33 has an average thickness st greater than about 500 nm. As used herein, the term "average thickness st" refers to the average thickness measured at multiple points across a plane (i.e., the xy plane) of each of the at least one surface layer 33. In some embodiments, the at least one surface layer 33 has an average thickness st greater than about 750 nm, greater than about 1000 nm, greater than about 1500 nm, or greater than about 2000 nm.

[0059] exist Figure 2A In the illustrated embodiments, at least one surface layer 33 comprises a pair of surface layers 33, and a plurality of polymer layers 43 are disposed between the pair of surface layers 33. At least one surface layer 33 can protect the plurality of polymer layers 43 and also provide mechanical stability to the optical film 30. In some cases, at least one surface layer 33 can act as a protective boundary layer (PBL).

[0060] Figure 2A A substantially collimated incident light 34a is further illustrated incident on the optical film 30. In some embodiments, the substantially collimated incident light 34a is incident on the optical film 30 at a first incident angle α1. The first incident angle α1 is less than about 10 degrees. In some embodiments, the first incident angle α1 is less than about 8 degrees, less than about 6 degrees, less than about 4 degrees, less than about 2 degrees, or less than about 1 degree. In some embodiments, the first incident angle α1 is about 0 degrees.

[0061] Figure 2A Example also illustrates substantially collimated incident light 34b incident on the optical film 30 at a second incident angle α2 of not less than about 20 degrees. In some embodiments, the second incident angle α2 is not less than about 25 degrees, not less than about 30 degrees, not less than about 35 degrees, not less than about 40 degrees, not less than about 45 degrees, not less than about 50 degrees, not less than about 55 degrees, or not less than about 60 degrees. In some embodiments, the second incident angle α2 is about 40 degrees. In some embodiments, the second incident angle α2 is about 60 degrees.

[0062] Figure 2B This is a detailed schematic cross-sectional view of a reflective polarizer 100 according to an embodiment of the present disclosure.

[0063] In some embodiments, the reflective polarizer 100 includes a plurality of polymer microlayers 143. The total number of the plurality of polymer microlayers 143 is at least 10. In some embodiments, the total number of the plurality of polymer microlayers 143 is at least 20, at least 50, at least 75, at least 100, at least 150, at least 200, at least 250, at least 300, or at least 400.

[0064] In some embodiments, each polymer microlayer in polymer microlayer 143 has an average thickness t1 of less than about 500 nm. As used herein, the term "average thickness t1" refers to the average thickness measured at multiple points across a plane (i.e., the xy plane) of each polymer microlayer in the plurality of polymer microlayers 143. In some embodiments, each polymer microlayer in polymer microlayer 143 has an average thickness t1 of less than about 400 nm, less than about 350 nm, less than about 300 nm, less than about 250 nm, or less than about 200 nm.

[0065] In some embodiments, the plurality of polymer microlayers 143 include a plurality of alternating first polymer microlayers 131 and second polymer microlayers 132. The plurality of alternating first polymer microlayers 131 and second polymer microlayers 132 are stacked along the thickness direction of the reflective polarizer 100 (i.e., substantially along the x-axis).

[0066] In some embodiments, the reflective polarizer 100 further includes at least one surface layer 133 disposed on a plurality of polymer microlayers 143. In some embodiments, the at least one surface layer 133 has an average thickness st1 greater than about 500 nm. As used herein, the term "average thickness st1" refers to the average thickness measured at multiple points across a plane (i.e., the xy plane) of each of the at least one surface layer 133. In some embodiments, the at least one surface layer 133 has an average thickness st1 greater than about 750 nm, greater than about 1000 nm, greater than about 1500 nm, or greater than about 2000 nm.

[0067] exist Figure 2B In the illustrated embodiment, at least one surface layer 133 comprises a pair of surface layers 133, and a plurality of polymer microlayers 143 are disposed between the pair of surface layers 133. At least one surface layer 133 may protect the plurality of polymer microlayers 143 and may also provide mechanical stability to the reflective polarizer 100. In some cases, at least one surface layer 133 may act as a protective boundary layer (PBL).

[0068] Figure 2B A further example is a substantially perpendicular incident light 35 incident on the reflective polarizer 100, that is, the incident light 35 is incident on the reflective polarizer 100 at an angle of 0 degrees relative to the normal of the reflective polarizer 100.

[0069] Figure 3 The optical film 30 is depicted according to an embodiment of this disclosure. Figure 1 and Figure 2A The optical transmittance of the multiple polymer layers 31, 32 (as shown) is related to the first incident angle a1 and the second incident angle a2 (as shown). Figure 2A (As shown) The substantially collimated incident light 34a, 34b Figure 2A The curve 350 shows the relationship between wavelengths (as shown in the figure).

[0070] Graph 350 further depicts the effect from one or more light sources 20 ( Figure 1 The emitted light 23v, 23b (as shown in the diagram) is emitted. Figure 1 The relationship between the emission spectrum and wavelength is shown in Figure 350. Figure 350 further depicts... Figure 1 The emission spectrum of one or more light conversion films 15 shown is related to wavelength.

[0071] Wavelength is expressed in nanometers (nm) on the horizontal axis. Optical transmittance is expressed as a percentage on the left vertical axis, while emission intensity is expressed in arbitrary units (au) on the right vertical axis.

[0072] The emitted light 23v, 23b includes an emission spectrum 50. The emission spectrum 50 includes a first emission peak 51v and a second emission peak 51b at corresponding first emission peak wavelength 52v and second emission peak wavelength 52b, and corresponding non-overlapping first full width at half maximum (FWHM) 53v and second full width at half maximum (FWHM) 53b.

[0073] Specifically, the first emitted light 23v includes the first emission spectrum 50v in emission spectrum 50, and the second emitted light 23b includes the second emission spectrum 50b in emission spectrum 50. The first emission spectrum 50v includes a first emission peak 51v at the first emission peak wavelength 52v and a first emission FWHM 53v. Similarly, the second emission spectrum 50b includes a second emission peak 51b at the second emission peak wavelength 52b and a second emission FWHM 53b. As is evident from graph 350, the first emitted light 23v does not include any wavelength from the second emission FWHM 53b, and the second emitted light 23b does not include any wavelength from the first emission FWHM 53v. Therefore, the first emission FWHM 53v and the second emission FWHM 53b are non-overlapping.

[0074] In some embodiments, the first emission peak wavelength 52V is less than about 420 nm. In some embodiments, the first emission peak wavelength 52V is less than about 415 nm, less than about 410 nm, or less than about 405 nm. Figure 3 In the example shown, the first emission peak wavelength 52V is approximately 400nm.

[0075] In some embodiments, the first emitt FWHM 53v is at least 5 nm wide. In some embodiments, the first emitt FWHM 53v is at least 10 nm wide or at least 15 nm wide. In some embodiments, the first emitt FWHM 53v is less than about 40 nm wide. In some embodiments, the first emitt FWHM 53v is less than about 35 nm wide, less than about 30 nm wide, less than about 25 nm wide, or less than about 20 nm wide. Figure 3 In the example shown, the first emitter FWHM 53v is positioned between approximately 393 nm and approximately 409 nm and is approximately 16 nm wide.

[0076] In some embodiments, the second emission peak wavelength 52b is greater than about 420 nm. In some embodiments, the second emission peak wavelength 52b is greater than about 425 nm, greater than about 430 nm, greater than about 435 nm, greater than about 440 nm, greater than about 445 nm, or greater than about 450 nm. Figure 3 In the example shown, the second peak wavelength 52b is approximately 452 nm.

[0077] In some embodiments, the second emitter FWHM 53b is at least 5 nm wide. In some embodiments, the second emitter FWHM 53b is at least 10 nm wide or at least 15 nm wide. In some embodiments, the second emitter FWHM 53b is less than about 40 nm wide. In some embodiments, the second emitter FWHM 53b is less than about 35 nm wide, less than about 30 nm wide, less than about 25 nm wide, or less than about 20 nm wide. Figure 3 In the example shown, the second emitter FWHM 53b is positioned between approximately 444 nm and approximately 462 nm and is approximately 18 nm wide.

[0078] In some embodiments, the first emission peak wavelength 52V is at least 10 nm smaller than the second emission peak wavelength 52B. In some embodiments, the first emission peak wavelength 52V is at least 15 nm, at least 20 nm, at least 25 nm, at least 30 nm, at least 35 nm, or at least 40 nm smaller than the second emission peak wavelength 52B. Figure 3 In the example shown, the first emission peak wavelength 52v is about 52nm smaller than the second emission peak wavelength 52b.

[0079] One or more light conversion films 15 include a green emission spectrum 50g and a red emission spectrum 50r, which include corresponding green peaks 51g and red peaks 51r at corresponding green peak wavelengths 52g and 52r, and corresponding non-overlapping green FWHM 53g and red FWHM 53r. Specifically, the green emission spectrum 50g includes a green peak 51g and a green FWHM 53g at the green peak wavelength 52g. The red emission spectrum 50r includes a red peak 51r and a red FWHM 53r at the red peak wavelength 52r. Furthermore, the green FWHM 53g and red FWHM 53r are non-overlapping. As is evident from graph 350, the green FWHM 53g is positioned between the second FWHM 53b and the red FWHM 53r.

[0080] The green and red light wavelengths are set in the corresponding green FWHM 53g and red FWHM 53r wavelengths. Specifically, the green light wavelength is 10g (… Figure 1 The green light wavelength (as shown) is set in the green light FWHM 53g, and the red light 10r (as shown) Figure 1 The red light wavelength (as shown in the figure) is set in the red light FWHM 53r.

[0081] In some implementations, the peak wavelength of the green light, 52g, is between approximately 490 nm and approximately 560 nm. Figure 3In the illustrated example, the green light peak wavelength 52g is approximately 527 nm. In some embodiments, the second emission peak wavelength 52b is at least 100 nm smaller than the green light peak wavelength 52g. In some embodiments, the second emission peak wavelength 52b is at least 95 nm, at least 90 nm, at least 85 nm, at least 80 nm, at least 75 nm, or at least 70 nm smaller than the green light peak wavelength 52g. Figure 3 In the example shown, the second emission peak wavelength 52b is about 75 nm smaller than the green light peak wavelength 52g.

[0082] In some embodiments, the green emission FWHM 53g is positioned within a green light wavelength range extending from about 490 nm to about 560 nm. In some embodiments, the green light wavelength range extends from about 515 nm to about 540 nm. In some embodiments, the second emission FWHM 53b does not overlap with the green emission FWHM 53g.

[0083] In some embodiments, the green FWHM 53g is at least 5 nm wide. In some embodiments, the green FWHM 53g is at least 10 nm wide, at least 15 nm wide, or at least 20 nm wide. In some embodiments, the green FWHM 53g is less than about 50 nm wide. In some embodiments, the green FWHM 53g is less than about 45 nm wide, less than about 40 nm wide, less than about 35 nm wide, less than about 30 nm wide, or less than about 25 nm wide. Figure 3 In the example shown, the green FWHM 53g is set between approximately 516nm and approximately 537nm, and is approximately 21nm wide.

[0084] In some implementations, the peak wavelength of the red light 52r is between approximately 590 nm and approximately 670 nm. Figure 3 In the illustrated example, the peak red light wavelength 52r is approximately 627 nm. In some embodiments, the red light FWHM 53r is set within a red light wavelength range extending from approximately 590 nm to approximately 670 nm. In some embodiments, the red light wavelength range extends from approximately 600 nm to approximately 670 nm.

[0085] In some embodiments, the red FWHM 53r is at least 5 nm wide. In some embodiments, the red FWHM 53r is at least 10 nm wide, at least 15 nm wide, at least 20 nm wide, at least 25 nm wide, at least 30 nm wide, at least 35 nm wide, or at least 40 nm wide. In some embodiments, the red FWHM 53r is less than about 80 nm wide. In some embodiments, the red FWHM 53r is less than about 75 nm wide, less than about 70 nm wide, less than about 65 nm wide, less than about 60 nm wide, less than about 55 nm wide, less than about 50 nm wide, or less than about 45 nm wide. Figure 3 In the example shown, the red FWHM 53r is set between approximately 607 nm and approximately 648 nm, and is approximately 41 nm wide.

[0086] Table 1 below summarizes the first emission peak wavelength 52v of the first emission spectrum 50v of the first emitted light 23v from one or more light sources 20, the second peak wavelength 52b of the second emission spectrum 50b of the second emitted light 23b from one or more light sources 20, the green peak wavelength 52g of the green emission spectrum 50g of the green light conversion film 15g, and the red peak wavelength 52r of the red emission spectrum 50r of the red light conversion film 15r.

[0087]

[0088] Graph 350 includes curve 302, which depicts the first angle of incidence α1 (a1) less than about 10 degrees (e.g., 0 degrees). Figure 2A (as shown) the substantially collimated incident light 34a Figure 2A (as shown in the diagram) and the optical transmittance of the optical film 30 for each of the mutually orthogonal in-plane first polarization state p and second polarization state s. In some embodiments, the first polarization state p extends substantially along the x-axis, and the second polarization state s extends substantially along the y-axis. In some embodiments, the first polarization state p may correspond to the p-polarization state, and the second polarization state may correspond to the s-polarization state.

[0089] refer to Figure 2A and Figure 3 As is evident from curve 302, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, the optical film 30 has an average optical transmittance of less than about 10% for the wavelength across the first emission FWHM 53v. In other words, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of less than about 10% for the wavelength across the first emission FWHM 53v.

[0090] In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of less than about 8%, less than about 6%, less than about 4%, less than about 2%, less than about 1%, less than about 0.5%, or less than about 0.1% for the wavelength across the first emission FWHM 53v.

[0091] exist Figure 2A and Figure 3 In the illustrated example, for substantially collimated incident light 34a, a first incident angle a1 of about 0 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of about 0% for the wavelength across the first emission FWHM 53v.

[0092] In some embodiments, the plurality of polymer layers 31, 32 have an average optical transmittance of less than about 10% for the violet wavelength range and the first incident angle a1, for substantially collimated incident light 34a and for each of the first polarization state p and the second polarization state s.

[0093] Therefore, for each of the first polarization state and the second polarization state across the first emission FWHM 53v and / or across the violet wavelength range, the optical film 30 can substantially block substantially collimated incident light 34a incident at the first incident angle α1. Therefore, the optical film 30 can substantially reflect the first emitted light 23v incident at the first incident angle α1. Therefore, the optical film 30 can reduce the optical transmission of violet light 23v to the display panel 40, thereby reducing the exposure of violet light 23v to the viewer's eyes.

[0094] Furthermore, for each of the substantially collimated incident light 34a, the first incident angle a1, and for each of the first polarization state p and the second polarization state s, the optical film 30 has an average optical transmittance greater than about 60% and less than about 95% for each of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r. In other words, for each of the substantially collimated incident light 34a, the first incident angle a1, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 60% and less than about 95% for each of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0095] In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 65%, greater than about 70%, greater than about 75%, or greater than about 80% and less than about 90% or less than about 85% for each of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0096] exist Figure 2A and Figure 3In the illustrated example, for substantially collimated incident light 34a, a first incident angle a1 of about 0 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of about 84.5% for the second emission FWHM 53b, about 89.5% for the green light FWHM 53g, and about 90.3% for the red light FWHM 53r.

[0097] Therefore, for each of the first and second polarization states of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r, the optical film 30 can substantially transmit substantially collimated incident light 34a incident at the first incident angle a1. Thus, the optical film 30 can substantially transmit the second light 10b, the green light 10g, and the red light 10r incident at the first incident angle a1.

[0098] Furthermore, for substantially collimated incident light 34a incident at the first incident angle a1 and for each of the first polarization state and the second polarization state, the optical transmittance of the optical film 30 across the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r can be substantially higher than the optical transmittance across the first emission FWHM 53v.

[0099] Graph 350 also includes curves 304 and 306, which depict substantially collimated incident light 34b incident at different second incident angles a2. Figure 2A (as shown in the diagram) and the optical transmittance of the optical film 30 for each of the first polarization state p and the second polarization state s. Specifically, curve 304 depicts the optical transmittance of the optical film 30 for substantially collimated incident light 34b incident at a second incident angle a2 of about 40 degrees, and for each of the first polarization state p and the second polarization state s. Furthermore, curve 306 depicts the optical transmittance of the optical film 30 for substantially collimated incident light 34b incident at a second incident angle a2 of about 60 degrees, and for each of the first polarization state p and the second polarization state s.

[0100] In some embodiments, for substantially collimated incident light 34b, a second incident angle a2 of not less than about 20 degrees, and for each of the first polarization state p and the second polarization state s, the optical film 30 has an average optical transmittance greater than about 20% for the wavelength across the first emission FWHM 53v. In other words, for substantially collimated incident light 34b, a second incident angle a2 of not less than about 20 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 20% for the wavelength across the first emission FWHM 53v.

[0101] In some embodiments, for substantially collimated incident light 34b, for a second incident angle a2 of not less than about 20 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 25%, greater than about 30%, greater than about 35%, or greater than about 40% for the wavelength across the first emission FWHM 53v.

[0102] Furthermore, for substantially collimated incident light 34b and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 20% for the violet wavelength range and a second incident angle a2 of not less than 30 degrees. In some embodiments, for substantially collimated incident light 34b and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 25%, greater than about 30%, greater than about 35%, or greater than about 40% for the violet wavelength range and a second incident angle a2 of not less than 30 degrees.

[0103] As is evident from curve 304, for substantially collimated incident light 34b, for a second incident angle a2 of approximately 40 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of approximately 39.7% for the wavelength across the first emission FWHM 53v.

[0104] Furthermore, in some embodiments, for substantially collimated incident light 34b, a second incident angle a2 of not less than about 20 degrees, and for each of the first polarization state p and the second polarization state s, the optical film 30 has an average optical transmittance greater than about 60% and less than about 95% for each of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r. In other words, for substantially collimated incident light 34b, a second incident angle a2 of not less than about 20 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average transmittance greater than about 60% and less than about 95% for each of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0105] In some embodiments, for substantially collimated incident light 34b, for a second incident angle a2 of not less than about 20 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average transmittance greater than about 65%, greater than about 70%, greater than about 75%, or greater than about 80% and less than about 90% or less than about 85% for each of the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0106] As is evident from curve 304, for substantially collimated incident light 34b, for a second incident angle a2 of approximately 40 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of approximately 82.5% for the second emission FWHM 53b, an average optical transmittance of approximately 84.7% for the green light FWHM 53g, and an average optical transmittance of approximately 85.8% for the red light FWHM 53r.

[0107] Therefore, for substantially collimated incident light 34b incident at the second incident angle a2 and for each of the first and second polarization states, the optical transmittance of the optical film 30 across the second FWHM 53b, green FWHM 53g, and red FWHM 53r can be higher than the optical transmittance across the first emission FWHM 53v. Thus, the optical film 30 can substantially transmit the second light 10b, green light 10g, and red light 10r incident at the second incident angle a2.

[0108] Reference curves 302, 304, and 306, for substantially collimated incident light 34b and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31 and 32 have an average optical transmittance greater than about 60% and less than about 95% for each of the blue light wavelength range, the green light wavelength range, and the red light wavelength range, and for each of the first incident angle a1 less than about 10 degrees and the second incident angle a2 not less than about 30 degrees.

[0109] In some embodiments, for substantially collimated incident light 34b, a second incident angle a2 of not less than about 30 degrees, and for each of the first polarization state p and the second polarization state s, the optical film 30 has an average optical transmittance greater than about 50% and less than about 95% for each of the first FWHM 53v, the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r. In other words, for substantially collimated incident light 34b, a second incident angle a2 of not less than about 30 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 50% and less than about 95% for each of the first FWHM 53v, the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0110] In some embodiments, for substantially collimated incident light 34b, for a second incident angle a2 of not less than about 30 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, or greater than about 80% and less than about 90% or less than about 85% for each of the first FWHM 53v, the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0111] As is evident from curve 306, for substantially collimated incident light 34b, for a second incident angle a2 of approximately 60 degrees, and for each of the first polarization state p and the second polarization state s, the plurality of polymer layers 31, 32 have an average optical transmittance of approximately 72.7% for the first emission FWHM 53v, an average optical transmittance of approximately 77.2% for the second emission FWHM 53b, an average optical transmittance of approximately 78.5% for the green light FWHM 53g, and an average optical transmittance of approximately 80.4% for the red light FWHM 53r.

[0112] Therefore, for substantially collimated incident light 34b incident at the second incident angle a2 and for each of the first and second polarization states, the optical film 30 is substantially optically transmittant across the first FWHM 53v, the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r.

[0113] Table 2 below summarizes the average optical transmittance of the optical film 30 for substantially collimated incident light incident at different incident angles (e.g., first incident angle a1 and second incident angle a2).

[0114]

[0115] Wherein, T30(0) refers to the average optical transmittance of optical film 30 for substantially collimated incident light incident at an incident angle of about 0 degrees.

[0116] T30(20) refers to the average optical transmittance of optical film 30 for substantially collimated incident light incident at an incident angle of about 20 degrees.

[0117] T30(40) refers to the average optical transmittance of optical film 30 for substantially collimated incident light incident at an angle of incidence of approximately 40 degrees; and

[0118] T30(40) refers to the average optical transmittance of the optical film 30 for substantially collimated incident light incident at an incident angle of about 60 degrees.

[0119] In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an average optical absorptivity greater than about 20% for the wavelength across the first emission FWHM 53v. In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an average optical absorptivity greater than about 30%, greater than about 40%, greater than about 50%, greater than about 60%, or greater than about 70% for the wavelength across the first emission FWHM 53v.

[0120] In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an optical absorptivity greater than about 20% for the first emission peak wavelength 52v. In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an optical absorptivity greater than about 30%, greater than about 40%, greater than about 50%, greater than about 60%, or greater than about 70% for the first emission peak wavelength 52v.

[0121] Therefore, for substantially collimated incident light 34a incident at the first incident angle a1 and for each of the first polarization state and the second polarization state, one or more optical conversion films 15 may have good optical absorption for the wavelength across the first emission FWHM 53v. In other words, for substantially collimated incident light 34a incident at the first incident angle a1 and for each of the first polarization state and the second polarization state, one or more optical conversion films 15 may have good optical absorption for violet light 23v.

[0122] Furthermore, in some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an average optical transmittance greater than about 50% for the wavelength across the second emission FWHM 53b. In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an average optical transmittance greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, or greater than about 85% for the wavelength across the second emission FWHM 53b.

[0123] In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an optical transmittance greater than about 50% for the second emission peak wavelength 52b. In some embodiments, for substantially collimated incident light 34a, a first incident angle a1, and for each of the first polarization state p and the second polarization state s, one or more optical conversion films 15 have an optical transmittance greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, or greater than about 85% for the second emission peak wavelength 52b.

[0124] Therefore, for substantially collimated incident light 34a incident at the first incident angle a1 and for each of the first and second polarization states, the optical film 30 is substantially optically transmittant across the second emission FWHM 53b. In other words, for substantially collimated incident light 34a incident at the first incident angle a1 and for each of the first and second polarization states, the optical film 30 is substantially optically transmittant for blue light 23b.

[0125] As discussed above, one or more light conversion films 15 are configured to convert at least a portion of the received emitted light 23v, 23b into green light 10g and red light 10r having corresponding green and red wavelengths. Figure 1 (as shown in the diagram). Specifically, in some embodiments, for substantially collimated incident light 34a, a first incident angle a1 of less than about 10 degrees, and for each of the first polarization state p and the second polarization state s, one or more light conversion films 15 convert at least a portion of the substantially collimated incident light 34a having wavelengths in the violet wavelength range into green light 10g and red light 10r having wavelengths in the corresponding green and red wavelength ranges.

[0126] Furthermore, in some embodiments, for substantially collimated incident light 34a, a first incident angle a1 of less than about 10 degrees, and for each of the first polarization state p and the second polarization state s, one or more light conversion films have an optical transmittance greater than about 50% for each of the blue light wavelength range, the green light wavelength range, and the red light wavelength range. In some embodiments, for substantially collimated incident light 34a, a first incident angle a1 of less than about 10 degrees, and for each of the first polarization state p and the second polarization state s, one or more light conversion films 15 have an optical transmittance greater than about 55%, greater than about 60%, greater than about 65%, or greater than about 70% for each of the blue light wavelength range, the green light wavelength range, and the red light wavelength range.

[0127] Therefore, for substantially collimated incident light 34a incident at the first incident angle a1 and for each of the first and second polarization states, the optical film 30 is substantially optically transmittant across the blue, green, and red light wavelength ranges. In other words, for substantially collimated incident light 34b incident at the first incident angle a1 and for each of the first and second polarization states, the optical film 30 is substantially optically transmittant for blue light 23b, green light 10g, and red light 10r.

[0128] refer to Figure 1 and Figure 3 In some embodiments, the optical diffuser 80 has a diffuse optical transmittance greater than about 30% for each of the second peak wavelength 52b, the green peak wavelength 52g, and the red peak wavelength 52r. In some embodiments, the optical diffuser 80 has a diffuse optical transmittance greater than about 35%, greater than about 40%, greater than about 45%, greater than about 50%, greater than about 55%, or greater than about 60% for each of the second peak wavelength 52b, the green peak wavelength 52g, and the red peak wavelength 52r.

[0129] See Figure 2B and Figure 3 In some embodiments, for each of the substantially perpendicular incident light 35 and the second peak wavelength 52b, the green peak wavelength 52g, and the red peak wavelength 52r, the plurality of polymer microlayers 131, 132 reflect more than about 60% of the incident light 35 having a first polarization state p and transmit more than about 60% of the incident light 35 having a second polarization state s. In some embodiments, for each of the substantially perpendicular incident light 35 and the second peak wavelength 52b, the green peak wavelength 52g, and the red peak wavelength 52r, the plurality of polymer microlayers 131, 132 reflect more than about 70%, more than about 80%, or more than about 90% of the incident light 35 having a first polarization state p and transmit more than about 70%, more than about 80%, or more than about 90% of the incident light 35 having a second polarization state s.

[0130] Figure 4 An example is illustrated of a back reflector 27 according to an embodiment of the present disclosure. Figure 1 The graph 450 shows the relationship between the optical reflectivity of the back reflector 27 and the wavelength. Specifically, graph 450 includes a curve 402 depicting the relationship between the optical reflectivity of the back reflector 27 and the wavelength. More specifically, curve 402 depicts the relationship between the optical reflectivity of the back reflector 27 and the wavelength for substantially perpendicular incident light 35 (shown in the diagram). Figure 2A As shown in the figure, the optical reflectivity of the back reflector 27.

[0131] Wavelength is expressed in nanometers (nm) on the horizontal axis. Optical reflectance is expressed as a percentage of reflectance on the vertical axis.

[0132] refer to Figure 1 , Figure 3 and Figure 4 As is evident from curve 402, in some embodiments, the back reflector 27 has an average optical reflectivity greater than about 80% for each of the first FWHM 53v, the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r. In some embodiments, the back reflector 27 has an average optical reflectivity greater than about 85%, greater than about 90%, greater than about 95%, greater than about 98%, greater than about 99%, or greater than about 99.5% for each of the first FWHM 53v, the second FWHM 53b, the green FWHM 53g, and the red FWHM 53r. Figure 1 and Figure 4 In the illustrated example, the back reflector 27 has an average optical reflectance of approximately 96.7% for the first emission FWHM 53v, approximately 99.7% for the second emission FWHM 53b, approximately 99.7% for the green light FWHM 53g, and approximately 99.7% for the red light FWHM 53r.

[0133] Table 3 below summarizes the average optical reflectivity of the back reflector 27 for substantially perpendicular incident light 35.

[0134]

[0135] in,

[0136] R27(0) refers to the average optical reflectivity of the back reflector 27 for substantially perpendicular incident light 35 incident at an incident angle of 0 degrees.

[0137] refer to Figures 1 to 4One or more light conversion films 15 can be more efficient in converting emitted light 23 (i.e., having emission spectra 50V and 50B in the corresponding violet and blue wavelength ranges) into green light 10G and red light 10R than in converting only blue light in the blue wavelength range into green light 10G and red light 10R. Furthermore, as discussed above, one or more light conversion films 15 may comprise quantum dot material. The absorption rate of quantum dot material for violet light 23V can be much higher than that for blue light 23B. Therefore, the amount of quantum dot material required for converting emitted light 23 including violet light 23V can be substantially less than the amount required for converting only blue light 23B in the blue wavelength range into green light 10G and red light 10R. This reduces the cost of one or more light conversion films 15 of the backlight 200. Furthermore, an optical film 30 disposed on one or more light conversion films 15 can reduce the amount of violet light 23V reaching the viewer's eyes. Specifically, the optical film 30 can essentially block a portion of the violet 23v light that is not absorbed by the quantum dot material to reduce the amount of violet 23v light reaching the viewer's eyes.

[0138] Unless otherwise stated, all figures used in the specification and claims to indicate feature dimensions, quantities, and physical properties should be understood to be modified by the term "about". Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations and can vary according to the desired properties sought by those skilled in the art using the teachings disclosed herein.

[0139] While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used in place of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications or variations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A backlight source for providing illumination to a display panel configured to display an image, the backlight source comprising: An extended illumination source includes one or more light sources and an extended emitting surface and is configured to emit light toward the display panel through the extended emitting surface. The emitted light includes an emission spectrum comprising a first emission peak and a second emission peak at corresponding first emission peak wavelengths and corresponding non-overlapping first emission full width at half maximum (FWHM) and second emission full width at half maximum (FWHM). One or more light conversion films are disposed on the extended emitting surface of the extended illumination source and include a green light emission spectrum and a red light emission spectrum. The green light emission spectrum and the red light emission spectrum include corresponding green and red peaks at corresponding green and red peak wavelengths, and corresponding non-overlapping green and red light FWHMs. The green light FWHM is disposed between the second FWHM and the red light FWHM. The one or more light conversion films are configured to receive light emitted through the extended emitting surface and convert at least a portion of the received emitted light into green and red light having corresponding green and red wavelengths disposed in the corresponding green and red FWHMs. An optical film, disposed opposite to the extended emission surface on one or more light conversion films, comprises at least 10 polymer layers, each polymer layer having an average thickness of less than about 500 nm, such that for substantially collimated incident light, a first incident angle of less than about 10 degrees, and for each of mutually orthogonal in-plane first and second polarization states, the plurality of polymer layers have an average optical transmittance of less than about 10% for wavelength across the first emission FWHM, and an average optical transmittance of greater than about 60% and less than about 95% for each of the second FWHM, the green FWHM, and the red FWHM.

2. The backlight source of claim 1, wherein for substantially collimated incident light, a second incident angle of not less than about 20 degrees, and for each of the first polarization state and the second polarization state, the plurality of polymer layers have an average optical transmittance greater than about 20% for the wavelength across the first emission FWHM, and an average optical transmittance greater than about 60% and less than about 95% for each of the second FWHM, the green FWHM, and the red FWHM.

3. The backlight according to claim 1, wherein for substantially collimated incident light, a second incident angle of not less than about 30 degrees, and for each of the first polarization state and the second polarization state, the plurality of polymer layers have an average optical transmittance greater than about 50% and less than about 95% for each of the first FWHM, the second FWHM, the green FWHM, and the red FWHM.

4. The backlight according to claim 1, wherein for the substantially collimated incident light, the first incident angle, and for each of the first polarization state and the second polarization state, the one or more light conversion films have an average optical transmittance greater than about 50% for the wavelength across the second emission FWHM.

5. The backlight according to claim 1, wherein for the substantially collimated incident light, the first incident angle, and for each of the first polarization state and the second polarization state, the one or more light conversion films have an optical transmittance greater than about 50% for the second emission peak wavelength.

6. The backlight of claim 1, wherein for the substantially collimated incident light, the first incident angle, and for each of the first polarization state and the second polarization state, the one or more light conversion films have an average optical absorption rate greater than about 20% for the wavelength across the first emission FWHM.

7. The backlight source of claim 1, wherein the light emitted from the one or more light sources comprises a first emitted light emitted from at least a first light source among the one or more light sources and a second emitted light emitted from at least a second light source among the one or more light sources, wherein: The first emitted light includes a first emission spectrum in the emission spectrum, the first emission spectrum including a first emission peak at the first emission peak wavelength having a corresponding first emission FWHM; and The second emitted light includes the second emission spectrum in the emission spectrum, the second emission spectrum including the second emission peak at the second emission peak wavelength having the corresponding second emission FWHM; The first emitted light does not include any wavelength from the second emitted FWHM, and the second emitted light does not include any wavelength from the first emitted FWHM.

8. The backlight according to claim 1, wherein the first emission peak wavelength is less than about 420 nm.

9. The backlight source according to claim 1, wherein the second emission peak wavelength is greater than about 420 nm.

10. An optical construct for use in a backlight of a display system, the backlight being configured to provide illumination to a display panel of the display system configured to display an image, the optical construct comprising: One or more light conversion films; An optical film disposed on one or more light conversion films and comprising at least 10 polymer layers, each polymer layer having an average thickness of less than about 500 nm; and An adhesive layer that bonds the optical film to the one or more light conversion films. For substantially collimated incident light, a first angle of incidence less than about 10 degrees, a second angle of incidence not less than about 30 degrees, a violet wavelength range extending from about 390 nm to about 410 nm, a blue wavelength range extending from about 440 nm to about 460 nm, a green wavelength range extending from about 515 nm to about 540 nm, and a red wavelength range extending from about 600 nm to about 670 nm, and for each of the mutually orthogonal in-plane first and second polarization states: The one or more light conversion films convert at least a portion of the substantially collimated incident light having wavelengths in the violet wavelength range into green and red light having wavelengths in the corresponding green and red wavelength ranges, and have an optical transmittance greater than about 50% for each of the blue, green, and red wavelength ranges. The plurality of polymer layers have an average optical transmittance of less than about 10% for the violet wavelength range and the first incident angle, an average optical transmittance of greater than about 20% for the violet wavelength range and the second incident angle, and an average optical transmittance of greater than about 60% and less than about 95% for each of the blue wavelength range, the green wavelength range, and the red wavelength range, and for each of the first incident angle and the second incident angle.

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