WO2019024605A1 - 面光源及显示装置 - Google Patents

面光源及显示装置 Download PDF

Info

Publication number
WO2019024605A1
WO2019024605A1 PCT/CN2018/090697 CN2018090697W WO2019024605A1 WO 2019024605 A1 WO2019024605 A1 WO 2019024605A1 CN 2018090697 W CN2018090697 W CN 2018090697W WO 2019024605 A1 WO2019024605 A1 WO 2019024605A1
Authority
WO
WIPO (PCT)
Prior art keywords
light source
sub
diffraction grating
waveguide layer
dimensional diffraction
Prior art date
Application number
PCT/CN2018/090697
Other languages
English (en)
French (fr)
Inventor
孟宪东
王维
董学
吕敬
陈小川
谭纪风
高健
孟宪芹
Original Assignee
京东方科技集团股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 京东方科技集团股份有限公司 filed Critical 京东方科技集团股份有限公司
Priority to US16/329,456 priority Critical patent/US11256010B2/en
Publication of WO2019024605A1 publication Critical patent/WO2019024605A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1814—Diffraction gratings structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1814—Diffraction gratings structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings
    • G02B5/1819—Plural gratings positioned on the same surface, e.g. array of gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133605—Direct backlight including specially adapted reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1861—Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1866—Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133614—Illuminating devices using photoluminescence, e.g. phosphors illuminated by UV or blue light
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/06—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 integrated waveguide
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2202/00—Materials and properties
    • G02F2202/36—Micro- or nanomaterials
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/22—Function characteristic diffractive

Definitions

  • the present disclosure relates to the field of display technologies, and in particular, to a surface light source and a display device.
  • Liquid crystal display as a light-transmitting display, requires a backlight structure to provide the brightness required for display.
  • Light Emitting Diode (LED) light source is the most commonly used light source in LCD direct-lit backlight structure. It has long life, small size and low voltage, but it is a point light source, and its uniformity of illumination is difficult. control.
  • a waveguide layer having opposite first and second surfaces; the second surface of the waveguide layer comprising a light extraction structure for uniformly deriving total reflection propagation in the waveguide layer Light
  • each of the light sources being located on a side of the first surface
  • each of the two-dimensional diffraction grating structures in one-to-one correspondence with the light source, each of the two-dimensional diffraction grating structures being located between the corresponding light source and the light-taking structure, each of the A two-dimensional diffraction grating structure is in contact with the waveguide layer, and the two-dimensional diffraction grating structure is configured to introduce light emitted by the corresponding light source into the waveguide layer.
  • an orthographic projection of the light source at the waveguide layer is located at a position of a corresponding two-dimensional diffraction grating structure at an orthographic projection center of the waveguide layer.
  • the two-dimensional diffraction grating structure satisfies the following conditions:
  • D is the diameter of the two-dimensional diffraction grating structure
  • d is the distance between the light source and the waveguide layer near a side surface of the two-dimensional diffraction grating structure.
  • the waveguide layer satisfies the following conditions: Where h is the thickness of the waveguide layer, ⁇ is the incident angle of light incident on the waveguide layer, and D is the diameter of the two-dimensional diffraction grating structure.
  • the thickness of the waveguide layer is greater than or equal to 2 microns.
  • the light extraction structure comprises one or a combination of the following: a plurality of dot structures, a plurality of grating structures.
  • the refractive index of the two-dimensional diffraction grating structure is greater than the refractive index of the waveguide layer.
  • the two-dimensional diffraction grating structure comprises a first sub-grating and a plurality of second sub-gratings surrounding the first sub-grating, the orthographic projection of the first sub-grating on the waveguide layer is circular
  • the orthographic projection of the plurality of second sub-gratings on the waveguide layer is a ring shape concentric with the circular shape and having a different radius.
  • the period, the line width, and the height of the first sub-grating and the at least one second sub-grating are not completely the same; the periods, line widths, and heights of at least two of the second sub-gratings are not completely the same.
  • the first sub-grating includes a plurality of first sub-structures
  • the line widths of the first sub-structures are not equal and the heights are not equal; or, the line widths of the first sub-structures are equal and the heights are not equal; or the line widths of the first sub-structures are not equal The height is equal.
  • each second sub-grating includes a plurality of second sub-structures
  • the line widths of the second sub-structures are not equal and the heights are not equal; or, the line widths of the second sub-structures are equal and the heights are not equal; or the line widths of the second sub-structures are not equal The height is equal.
  • the two-dimensional diffraction grating structure is in contact with the first surface; the light source has a set distance from the first surface.
  • the two-dimensional diffraction grating structure is in contact with the second surface; the light-projecting structure and the orthographic projection of the two-dimensional diffraction grating structure on the waveguide layer do not overlap each other.
  • the light source is in contact with the first surface.
  • the light source is a monochromatic light source
  • the surface light source further includes: a monochromatic light conversion layer located on a light exiting side of the surface light source;
  • the monochromatic light conversion layer is for converting monochromatic light emitted by the light source into white light.
  • the monochromatic light conversion layer comprises one or a combination of the following: a fluorescent film layer, a quantum dot film layer.
  • the method further includes: a reflective layer located on a side of the monochromatic light conversion layer away from the waveguide layer.
  • the embodiment of the present disclosure further provides a display device including the surface light source provided by the embodiment of the present disclosure.
  • Figure 1 is a distribution diagram showing the light field distribution of a single LED light source showing a Bob curve
  • FIG. 2 to FIG. 7 are schematic structural diagrams of a surface light source according to some embodiments of the present disclosure.
  • FIG. 8 is a schematic structural diagram of a two-dimensional diffraction grating structure in a surface light source according to some embodiments of the present disclosure.
  • FIG. 9 is a schematic top plan view of a two-dimensional diffraction grating structure according to some embodiments of the present disclosure.
  • FIG. 10 is a schematic diagram of an optimization process of a two-dimensional diffraction grating structure according to some embodiments of the present disclosure.
  • FIG. 11 is a schematic diagram of a light field size of an LED light source according to some embodiments of the present disclosure.
  • FIG. 12 is a schematic cross-sectional view of a first sub-grating along a direction parallel to a waveguide layer according to some embodiments of the present disclosure
  • Figure 13 is a schematic cross-sectional view along line AA' of Figure 12;
  • FIG. 14 is a schematic cross-sectional view of a first sub-grating along its diameter according to some embodiments of the present disclosure
  • 15 is a schematic cross-sectional view of a first sub-grating along its diameter according to some embodiments of the present disclosure
  • Figure 16 is a schematic cross-sectional view of the two-dimensional diffraction grating structure shown in Figure 9 along the radial direction;
  • FIG. 17 is a graph showing a relationship between a principal ray angle and an optical coupling efficiency provided by some embodiments of the present disclosure.
  • FIG. 18 is a schematic cross-sectional view showing a diameter direction of a two-dimensional diffraction grating structure in one cycle of any sub-grating according to some embodiments of the present disclosure
  • FIG. 19 is a partial optimization result diagram of optical coupling efficiency of each sub-grating of a two-dimensional diffraction grating structure according to some embodiments of the present disclosure.
  • FIG. 20 is a schematic structural diagram of a display device according to some embodiments of the present disclosure.
  • FIG. 21 is a schematic diagram showing the principle of a two-dimensional diffraction grating structure having high coupling efficiency for light rays of two polarization directions according to some embodiments of the present disclosure.
  • the direct-lit backlight structure is improved by increasing the longitudinal light-mixing distance between the LEDs and reducing the spacing between the LEDs. Light-emitting uniformity of the direct-lit backlight structure.
  • the longitudinal light mixing distance between adjacent LED light sources in the direct type backlight structure in the related art is in the range of 2 mm (mm) to 22 mm.
  • the horizontal spacing between the LEDs is small, the number of LEDs used in the direct-lit backlight structure is very large, about tens of thousands.
  • Embodiments of the present disclosure provide a surface light source and a display device for reducing the thickness of a surface light source, that is, a direct type backlight structure, and reducing the number of LEDs used in the surface light source to reduce cost.
  • a surface light source provided by an embodiment of the present disclosure, as shown in FIG. 2 to FIG. 7, includes:
  • the waveguide layer 1 has a first surface 11 and a second surface 12 opposite thereto; the second surface 12 of the waveguide layer 1 comprises a light-harvesting structure 2 for uniformly deriving the total reflection propagation in the waveguide layer 1 Light
  • each of the light sources 3 being located on a side of the first surface 11;
  • each of the two-dimensional diffraction grating structures 4 is in one-to-one correspondence with the light source 3, and each of the two-dimensional diffraction grating structures 4 is located between the corresponding light source 3 and the light-taking structure 2, and each two-dimensional diffraction grating structure 4 In contact with the waveguide layer 1, the two-dimensional diffraction grating structure 4 is used to introduce light emitted from the corresponding light source 3 into the waveguide layer 1.
  • the light energy and direction emitted from the light extraction structure 2 are evenly distributed, so that there is no light mixing distance in the surface light source.
  • the uniformity of the point source is difficult to control. Therefore, it is not necessary to increase the longitudinal light mixing distance of the light source 3 to achieve uniform light output, thereby reducing the overall thickness of the surface light source and reducing the production cost.
  • the uniformity of the light emitted by the surface light source is controlled by the light-harvesting structure 2, so that the single light source 1 can provide an overall backlight of the single-area region, so that the number of the light sources 1 in the surface light source can be greatly reduced, thereby cut costs.
  • the two-dimensional diffraction grating structure 4 may be located on the first surface 11 of the waveguide layer 1, that is, the two-dimensional diffraction grating structure 4 and A surface 11 is in contact, and at this time, the light source 3 needs to have a set distance from the first surface 11.
  • the two-dimensional diffraction grating structure 4 may also be located on the second surface 12 of the waveguide layer 1 , that is, the two-dimensional diffraction grating structure 4 .
  • the orthographic projection of the light-harvesting structure 2 and the two-dimensional diffraction grating structure 4 on the waveguide layer 1 generally does not overlap each other; that is, when the light-harvesting structure 2 and the two-dimensional diffraction grating structure 4 are simultaneously located in the waveguide
  • the position of the two-dimensional diffraction grating structure 4 may be omitted.
  • the light source 1 when the two-dimensional diffraction grating structure 4 is in contact with the second surface 12, as shown in FIG. 5 and FIG. 7, the light source 1 may be in contact with the first surface 11, This can further reduce the thickness of the surface light source.
  • the two-dimensional diffraction grating structure 4 and the waveguide layer 1 may each adopt a transparent material.
  • the material of the two-dimensional diffraction grating structure 4 may be selected from silicon nitride (Si). 3 N 4 ), the material of the waveguide layer 1 may be selected from indium tin oxide (ITO) or Si 3 N 4 , which is not limited herein.
  • the refractive index of the two-dimensional diffraction grating structure 4 is generally greater than the refractive index of the waveguide layer 1. In this way, the light passing through the surface light source has high optical coupling efficiency, thereby improving the utilization rate of the light source 1 and saving energy.
  • the refractive index of the waveguide layer 1 needs to be larger than that of the medium contacting the waveguide layer 1 except the two-dimensional diffraction grating structure 4 and the light extraction structure 2. Rate, thereby achieving total reflection transmission of light in the waveguide layer 1.
  • the medium in contact with the waveguide layer 1 is air, that is, the refractive index of the waveguide layer 1 needs to be larger than the refractive index of air.
  • the light extraction structure 2 may include one or a combination of the following: a plurality of dot structures, a plurality of grating structures.
  • the light taking structure 2 may be a separate structure, or may be directly formed on the waveguide layer 1.
  • the dot structure may directly sit on the second surface 12 of the waveguide layer 1, and the grating structure may be independent of the waveguide layer 1. There is no limit here.
  • the distance between the light source 1 and the light extraction structure 2 is different, and the light intensity of the light reaching the light extraction structure 2 is also different, and the light according to the light extraction structure 2 needs to be obtained.
  • the design of the size and the dense arrangement of the dot structure is strongly designed, or the period, duty cycle and height of the grating structure are designed according to the light intensity reaching the light-taking structure 2.
  • the typical size of the dot structure is in the range of 0.1 to 1 mm.
  • the diffraction efficiency of the two-dimensional diffraction grating structure 4 at different positions on the surface of the waveguide layer 1 can be set differently, and the diffraction efficiency of the two-dimensional diffraction grating structure 4 near the position of the light source 1 is smaller than the diffraction efficiency away from the position of the light source 1, thereby The light energy emitted by the light taking structure 2 is evenly distributed.
  • the orthographic projection of the light source 3 in the waveguide layer 1 is generally located in the corresponding two-dimensional diffraction grating structure 4 in the waveguide layer 1 . At the center of the projection.
  • the two-dimensional diffraction grating structure 4 may be, for example, a structure as shown in FIG. 8 , and the two-dimensional diffraction grating structure 4 includes a plurality of sub-structures 41 and a two-dimensional diffraction grating structure. 4
  • the X direction and the Y direction along the rectangular coordinate plane in which it is located have periodicity, that is, the substructures 41 are periodically arranged in the X direction and the Y direction.
  • the lengths of a and e correspond to the line widths of the two-dimensional diffraction grating structure 4 in the X direction and the Y direction, respectively, and the length of c corresponds to the height of the two-dimensional diffraction grating structure 4 (when each substructure 41 is stepped)
  • the two-dimensional diffraction grating structure 4 includes a plurality of height parameters, and the lengths of b and d correspond to the periods of the two-dimensional diffraction grating structure 4 in the X direction and the Y direction, respectively.
  • the lengths of a and e may be equal or unequal, and the lengths of b and d may be equal and unequal, that is, the line widths and periods of the two-dimensional diffraction grating structure 4 in the X direction and the Y direction are equal.
  • the two-dimensional diffraction grating structure 4 may also be disposed such that there is no gap between the adjacent two sub-structures 41, that is, the two-dimensional diffraction grating structure 4 is in the X direction.
  • the line width in the Y direction is equal to the period of the two-dimensional diffraction grating structure 4 in the X direction and the Y direction.
  • the sub-structure 41 is periodically arranged along the X direction and the Y direction, that is, one sub-structure 41 corresponds to one period of the two-dimensional diffraction grating structure 4.
  • the two-dimensional diffraction grating structure 4 may have other shapes corresponding to one cycle of the two-dimensional diffraction grating structure 4, which is not limited herein.
  • the two-dimensional diffraction grating structure 4 may include a first sub-grating 42 and a plurality of second sub-gratings 43 surrounding the first sub-grating 42 .
  • the orthographic projection of the first sub-grating 42 on the waveguide layer 1 is circular
  • the orthographic projection of the plurality of second sub-gratings 43 on the waveguide layer 1 is a ring having a concentricity with a circular shape and a different radius.
  • FIG. 9 is an illustration of a two-dimensional diffraction grating structure 4 including three sub-gratings.
  • the two-dimensional diffraction grating structure 4 of the above-mentioned surface light source provided by the embodiment of the present disclosure may also have other shapes, and the first sub-grating and the second sub-grating may also have other shapes, which are not limited herein.
  • the structure of the two-dimensional diffraction grating structure 4 in the above-mentioned surface light source can be optimized by strict coupling wave theory and related algorithms (for example, simulated annealing algorithm).
  • the two-dimensional diffraction grating structure 4 that performs high-efficiency coupling of the light beam with the divergence angle of the LED of -60° to 60° into the waveguide layer 1 for total reflection transmission is optimized. Includes the following steps:
  • FIG. 11 is a schematic diagram of the light field of the right half of the LED light source 3.
  • the light source 3 having a distance d from the waveguide layer 1 since the main energy is concentrated in the range of 0° to 60°, the light source is 3
  • the light field size L at the lower surface of the waveguide layer 1 can be determined:
  • the lower surface L of the waveguide layer 1 is sampled into a plurality of equally spaced small regions P, so that the optical coupling efficiency of the light passing through the small region P of the light source 3 satisfies a preset condition.
  • Each small area P in FIG. 11 corresponds to each sub-grating of the two-dimensional diffraction grating structure 4. Since the size of the LED light source 3 is determined, the angular range of the small area P of the sample emitted by the LED light source 3 passes through the sample It is determined that the angle of view of the LED light source 3 passing through each small area P is determined.
  • the range of the light angle distribution through each small area P may be limited to, for example, 5 degrees. It should be noted that the range of the light angle distribution through each small area P can be determined according to the size of the LED light source 3 and the distance between the LED light source 3 and the waveguide layer 1.
  • the structure of each sub-grating is optimized, so that the light emitted by the light source 3 and reaching the two-dimensional diffraction grating structure 4 and then re-emitted is totally reflected and transmitted in the waveguide layer 1, and the coupling efficiency of the chief ray in each small region is small.
  • each sub-grating in the two-dimensional diffraction grating structure 4 can be optimized by quantizing the range of the ray angle of the LED light source 3 from the field of view.
  • the preset condition that the optical coupling efficiency is satisfied may be set according to actual needs, and the preset condition of the optical coupling efficiency selected by the embodiment of the present disclosure is such that the light source 3 emits and reaches the two-dimensional diffraction grating structure 4 and then exits again.
  • the light coupling efficiency of the light is greater than 60%.
  • the size of the two-dimensional diffraction grating structure 4 on the surface of the waveguide layer 1 corresponds to the entire light field of the LED light source 3.
  • the two-dimensional diffraction grating structure 4 satisfies the following conditions. :
  • D is the diameter of the two-dimensional diffraction grating structure 4
  • d is the distance between the light source 3 and the surface of the waveguide layer 1 near the two-dimensional diffraction grating structure 4.
  • the period, the line width, and the height of the first sub-grating 42 and the at least one second sub-grating 43 are not completely the same, and the periods of the at least two second sub-gratings 43 are The line width and height are not exactly the same. Since the grating is sensitive to the angle of the incident light, the sub-gratings are set to have different periods, line widths and heights, so that the coupling efficiency of a two-dimensional diffraction grating structure 4 to incident light of multiple angles can be realized, and the efficiency is further improved.
  • the first sub-grating 42 may include a plurality of first sub-structures 421 ; specifically, for example, FIG. 5
  • FIG. 5 In the two-dimensional diffraction grating structure 4, the cross-sectional view of the first sub-grating 42 in the direction parallel to the waveguide layer 1 is as shown in FIG. 12, and the cross-sectional view of the first sub-grating 42 along AA' in FIG.
  • each period 42' of the first sub-grating 42 includes three annular first sub-structures 421 (the first sub-structure 421 corresponding to the center of the first sub-grating 42 can be regarded as a ring having an inner ring radius of 0);
  • the line widths of the first sub-structures 421 may not be equal, and the heights may not be equal.
  • the line widths f1 and heights of the three first sub-structures 421 in any period of the first sub-grating 42 shown in FIGS. 12 and 13 F2 is not equal.
  • the line widths of the first sub-structures 421 are equal and the heights are not equal, that is, the cross-sectional view of the first sub-grating 42 along its diameter may also be as shown in FIG. 14 , and the three first sub-structures in any period 42′
  • the line width f1 of 421 is equal, but the height f2 is not equal.
  • the line widths of the first sub-structures 421 are unequal and equal in height, that is, the cross-sectional view of the first sub-grating 42 along its diameter is as shown in FIG. 15, and each period 42' includes a line of the annular first sub-structure 421. Both the width f1 and the height f2 are equal. It can be understood that when the line width f1 and the height f2 of the first sub-structure 421 are the same, a gap needs to exist between the adjacent first sub-structures 421.
  • each second sub-grating 43 may include a plurality of second sub-structures 431;
  • the line widths of the second sub-structures 431 may not be equal, and the heights may not be equal; or the line widths of the second sub-structures 431 are equal and the heights are not equal; or the line widths of the second sub-structures 431 are not equal.
  • the height is equal.
  • the orthographic projection on the waveguide layer 1 is a two-dimensional grating as shown in FIG. 9
  • a cross-sectional view along the diameter direction thereof is as shown in FIG.
  • the first sub-grating 42 and the two second sub-gratings 43 each include at least two periods, and the first sub-grating 42 and the second sub-grating 43 include three line widths f1 and a height f2 in one period 42' (43').
  • the first substructure 421 and the second substructure 431 are all unequal.
  • the coupled wave algorithm based on simulated annealing algorithm is selected to optimize the two-dimensional diffraction grating structure 4 in a global form.
  • the optical coupling efficiency diagram corresponding to the incident angle of each small area P is as shown in FIG. As can be seen from Fig.
  • the optical coupling efficiency of the chief ray is greater than 60%
  • the structural parameters of the corresponding sub-grating are shown in Table 1, and the optimized one is in one cycle of any sub-grating.
  • a cross-sectional view of the two-dimensional diffraction grating structure 4 in the diameter direction is as shown in FIG. 18, and includes four line widths f1 which are not equal, and the height f2 is not equal to the first sub-structure 421 (second sub-structure 431).
  • the partial optimization result of the optical coupling efficiency of each sub-grating of the two-dimensional diffraction grating structure 4 is as shown in FIG. 19, the I angle in FIG. 19 represents the incident angle of the light incident on the grating, and T represents the transmission efficiency of the grating. R represents the reflection efficiency of the grating, and the numbers after T and R represent the diffraction order.
  • the circled portion of the black thick line frame in Fig. 19 represents the diffraction angle at which the angle satisfies the total reflection condition. It can be seen from the efficiency column that the optimized result is obtained.
  • the two-dimensional diffraction grating structure 4 can deflect most of the light diffraction at the total reflection angle to achieve coupling in the waveguide layer 1, that is, total reflection transmission occurs.
  • the size of each small region P may not be equal, so that any one of the corresponding The width of the grating along the radial direction of the two-dimensional diffraction grating structure 4 is also not equal.
  • the obtained two-dimensional diffraction grating structure 4 is obtained as long as the light entering the waveguide layer 1 through the two-dimensional diffraction grating structure 4 is totally reflected and transmitted in the waveguide layer 1 and has high coupling efficiency, and each sub-grating is in one cycle.
  • Substructures having equal line widths but not equal heights may be included, or substructures of equal height but unequal line widths may be included.
  • the above-mentioned surface light source provided by the embodiment of the present disclosure
  • the waveguide layer 1 can satisfy the following conditions:
  • h is the thickness of the waveguide layer 1
  • ⁇ is the incident angle of the light emitted from the light source 3 and reaching the waveguide layer 1 after reaching the two-dimensional diffraction grating structure 4.
  • the diffraction of the light entering the waveguide layer 1 at the interface between the waveguide layer 1 and the two-dimensional diffraction grating structure 4 destroys the total reflection process of the light, and therefore the thickness of the waveguide layer 1 satisfies the above conditions, from two-dimensional diffraction.
  • the light diffracted into the waveguide layer 1 at the center position of the grating structure 4 is not subjected to the diffraction modulation of the two-dimensional diffraction grating structure 4 to destroy the total reflection transmission condition during the total reflection transmission.
  • the thickness of the waveguide layer 1 may be, for example, 2 micrometers.
  • the thickness of the waveguide layer 1 may also be increased to several tens of micrometers, which is not limited herein.
  • the light source 3 may be an LED, and the chip of the LED may be selected from an inorganic semiconductor material or an organic light emitting material, which is not limited herein.
  • the light source 3 may be a monochromatic light source.
  • a monochromatic light source for example, an LED with a blue color of light can be selected, and an LED with an optical band of ultraviolet light can be selected.
  • a monochromatic light source with a color of other colors can be selected, which is not limited herein.
  • the method further includes: a monochromatic light conversion layer 5 located on the light exiting side of the surface light source, and the monochromatic light conversion layer 5 is used for The light emitted from the light source 3 is converted into white light.
  • the monochromatic light conversion layer 5 may include one or a combination of the following: a fluorescent film layer, a quantum dot film layer.
  • the fluorescent film layer may, for example, be selected from yttrium aluminum garnet (Y 3 Al 5 O 12 :Ce ⁇ 3+); the quantum dot film layer includes a quantum dot material, and the quantum dots are composed of a finite number of atoms, Dimensional dimensions are all on the order of nanometers.
  • Quantum dots are generally spherical or spheroidal, usually made of a semiconductor material consisting of elements of IIB-VIA or IIIA-VA of the periodic table, or two or more semiconductor materials, elements of IIB-VIA.
  • the semiconductor material of the composition may be, for example, cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), zinc selenide (ZnSe), etc.
  • the semiconductor material composed of elements of IIIA to VA may be, for example, indium phosphide. (InP), indium arsenide (InAs), etc., and quantum dots having a stable diameter of 2 to 20 nm.
  • the reflective layer 6 located on the side of the monochromatic light conversion layer 5 away from the waveguide layer 1 may be further included.
  • the reflection layer 6 since the utilization of the two-dimensional diffraction grating structure 4 to couple the light emitted from the LED light source 3, there will inevitably be a reflection diffraction loss, so that the reflection layer 6 can be provided to re-use the light that reflects the diffraction loss.
  • the reflective layer 6 may be a metal film layer, for example, aluminum or silver may be selected as the metal material, and the reflective layer may also be a multilayer dielectric film or other material having a function of reflecting light.
  • the LED light source 3 may be disposed on the reflective layer 6 and located between the waveguide layer 1 and the reflective layer 6, and the two-dimensional diffraction grating structure 4
  • the waveguide layer 1 is disposed near the first surface 11 of the LED light source 3, and the dot structure as the light extraction structure 2 is disposed on the second surface 12 of the waveguide layer 1 away from the LED light source 3, and the fluorescent film layer as the monochromatic light conversion layer 5 is located.
  • the light extraction structure 2 is disposed on the reflective layer 6 and located between the waveguide layer 1 and the reflective layer 6, and the two-dimensional diffraction grating structure 4
  • the waveguide layer 1 is disposed near the first surface 11 of the LED light source 3
  • the dot structure as the light extraction structure 2 is disposed on the second surface 12 of the waveguide layer 1 away from the LED light source 3, and the fluorescent film layer as the monochromatic light conversion layer 5 is located.
  • the light extraction structure 2 is disposed on the reflective layer 6 and located between the waveguide layer 1 and the reflective layer 6, and the
  • the two-dimensional diffraction grating structure 4 and the light-taking structure 2 may be disposed on the first surface 11 of the waveguide layer 1 away from the LED light source 3.
  • the light extraction structure 2 is not provided at the position where the waveguide layer 1 is provided with the two-dimensional diffraction grating structure 4, and the two-dimensional diffraction grating structure 4 is a reflection type grating.
  • the LED light source 3 can also be directly in contact with the first surface 11 of the waveguide layer 1 adjacent to the LED light source 3, as shown in FIG. 5, that is, the LED light source 3 and the waveguide layer 1
  • the distance between the two is zero, and the surface light source shown in FIG. 5 can further reduce the thickness of the surface light source compared to the surface light source shown in FIG.
  • the LED light source 3 may also be disposed under the fluorescent film layer 5 and located between the waveguide layer 1 and the fluorescent film layer 5 toward the waveguide layer.
  • the light exiting, the two-dimensional diffraction grating structure 4 and the light-taking structure 2 are both disposed on the second surface 12 of the waveguide layer 1 remote from the LED light source 3.
  • the distance between the LED light source 3 and the waveguide layer 1 is about zero, and the light extraction structure 2 is not provided at the position where the waveguide layer 1 is provided with the two-dimensional diffraction grating structure 4, and the two-dimensional diffraction grating structure 4 is a reflection type grating.
  • the LED light source 3 can also be directly in contact with the first surface 11 of the waveguide layer 1 adjacent to the LED light source 3, as shown in FIG. 7, that is, the LED light source 3 and the waveguide layer 1 The distance between the two is zero.
  • the surface light source shown in Fig. 7 can further reduce the thickness of the surface light source.
  • the distance between the light source 3 and the waveguide layer 1 has no influence on the light uniformity of the surface light source, and the distance between the light source 3 and the waveguide layer 1 only affects the light coupling efficiency of the surface light source.
  • the greater the distance between the light source 3 and the waveguide layer 1 the higher the light coupling efficiency of the surface light source.
  • the thickness of the integrated surface light source and the light coupling efficiency required by the surface light source are required to determine the light source.
  • the distance between the light source 3 and the waveguide layer 1 is greater than or equal to zero.
  • an embodiment of the present disclosure further provides a display device including the above surface light source provided by the embodiment of the present disclosure.
  • the above display device provided by the embodiment of the present disclosure may be a liquid crystal display device.
  • the display device provided by the embodiment of the present disclosure includes a surface light source 10 , a lower polarizer layer 20 on the surface light source 10 , a display panel 30 on the lower polarizer layer 20 , and a display panel 30 .
  • the upper polarizer layer 40, wherein the surface light source 10 can be any of the surface light sources provided by the embodiments of the present disclosure.
  • the two-dimensional diffraction grating structure 4 makes the light coupling efficiency of the light of any polarization direction emitted by the light source 3 satisfy a preset condition.
  • the preset condition that the optical coupling efficiency is satisfied may be, for example, that the optical coupling efficiency is greater than 60%.
  • the first two-dimensional diffraction grating structure 4 is optimized for the first polarization direction of the light, and then the second polarization direction of the light is optimized, and the first polarization direction of the light is different from the second polarization direction of the light.
  • the second two-dimensional diffraction grating structure 4, and then the optimized first two-dimensional diffraction grating structure 4 and the second two-dimensional diffraction grating structure 4 are again optimized (for example, adjusting the height and line width of different positions in the two-dimensional direction of the grating), Superimposed to form a two-dimensional diffraction grating structure 4, the light coupling efficiency of the light of the first polarization direction and the second polarization direction is greater than 60%, that is, the two-dimensional diffraction grating structure 4 is made by the light source 3
  • the two polarization directions of the emitted light have higher optical coupling efficiency, which further improves the utilization of the light source in the surface light source.
  • the schematic diagram of the two-dimensional diffraction grating structure 4 in the surface light source having high coupling efficiency for the two polarization directions of light is shown in FIG. 21, and the two-dimensional diffraction grating structure 4 is optimized.
  • the first two-dimensional diffraction grating structure and the second two-dimensional diffraction grating structure are again optimized and superposed. It should be noted that the two-dimensional diffraction grating structure 4 in FIG.
  • 21 is a schematic cross-sectional view parallel to the plane of the waveguide layer 1,
  • the structure corresponding to the cross section 4' of the diffractive grating structure 4 in the Y direction and the cross section 4" of the two-dimensional diffraction grating structure 4 along the X direction respectively make the optical coupling efficiency of the light of the two polarization directions satisfy the preset condition, two-way
  • the arrow represents the polarization direction of the light whose polarization direction is parallel to the paper surface
  • the solid dot represents the polarization direction of the light whose polarization direction is perpendicular to the paper surface.
  • the structure corresponding to the cross section 4' of the two-dimensional diffraction grating structure 4 in the Y direction is for the polarization direction and
  • the reflection of the light in the direction corresponding to the solid dot is less and the optical coupling efficiency is higher, and the opposite of the direction of the polarization direction and the direction corresponding to the double-headed arrow
  • the structure corresponding to the cross section 4" of the two-dimensional diffraction grating structure 4 in the X direction has less reflection of light having the same direction of polarization and the direction corresponding to the double-headed arrow, and the light coupling efficiency is higher, and for the polarization direction and the solid circle
  • the light in the direction corresponding to the point has more reflection, and the angles of the angles a and b in the figure are larger than the total reflection critical angle when the waveguide layer satisfies the total reflection condition, and thus the cross section 4' in the Y direction with the two-dimensional diffraction grating structure 4.
  • the above display device may adopt a local diming technique to reduce power consumption, improve imaging contrast, increase gray scale, and reduce image sticking.
  • the surface light source and the display device have a problem that the surface light source does not have a light mixing distance because the light is totally reflected and transmitted in the waveguide layer, and there is no problem that the uniformity of the point source light source is difficult to control, and there is no need to increase the light source.
  • the longitudinal light mixing distance is used to achieve uniform light output, thereby reducing the overall thickness of the surface light source and reducing the production cost.
  • the uniformity of the light emitted by the surface light source is controlled by the light-taking structure, so that a single light source can provide an overall backlight of a single block, so that the number of light sources in the surface light source can be greatly reduced, thereby reducing the cost.

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Planar Illumination Modules (AREA)
  • Liquid Crystal (AREA)

Abstract

一种面光源（10），包括波导层（1）和光栅结构（4），波导层具有相对设置的第一表面（11）和第二表面（12），光栅结构设置在波导层的第一或第二表面，光栅结构用于将入射至光栅结构的光线导入到波导层中并在波导层中全反射传播。这种面光源结构使得从光场调制层出射的光的能量及方向均匀分布，减少了面光源的厚度及面光源中LED的使用数目。还公开了一种显示装置。

Description

面光源及显示装置
相关申请的交叉引用
本公开要求在2017年8月01日提交中国专利局、申请号为201710647865.0、发明名称为“一种光场调制层、背光结构及显示装置”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本公开涉及显示技术领域，尤其涉及一种面光源及显示装置。
背景技术
液晶显示器(Liquid Crystal Display，LCD)作为一种透光型显示器，显示时需要背光结构提供显示所需要的亮度。发光二极管(Light Emitting Diode，LED)光源是目前LCD直下式背光结构中最常用的光源，它具有寿命长，体积小，低电压等特点，但是它属于点型光源，其发光的均匀性很难控制。
发明内容
本公开实施例提供的一种面光源，其中，包括：
波导层，所述波导层具有相对的第一表面和第二表面；所述波导层的所述第二表面包括取光结构，所述取光结构用于均匀导出在所述波导层全反射传播的光线；
多个光源，各所述光源位于所述第一表面一侧；
多个二维衍射光栅结构，各所述二维衍射光栅结构与所述光源一一对应，各所述二维衍射光栅结构位于对应的所述光源与所述取光结构之间，各所述二维衍射光栅结构与所述波导层接触，所述二维衍射光栅结构用于将对应的所述光源发出的光线导入所述波导层。
可选地，所述光源在所述波导层的正投影位于对应的所述二维衍射光栅 结构在所述波导层的正投影中心位置处。
可选地，所述二维衍射光栅结构满足如下条件：
Figure PCTCN2018090697-appb-000001
其中，D为所述二维衍射光栅结构的直径，d为所述光源与所述波导层靠近所述二维衍射光栅结构一侧表面之间的距离。
可选地，所述波导层满足如下条件：
Figure PCTCN2018090697-appb-000002
其中，h为所述波导层的厚度，θ为入射至所述波导层的光线入射角，D为所述二维衍射光栅结构的直径。
可选地，所述波导层的厚度大于等于2微米。
可选地，所述取光结构包括下列之一或其组合：多个网点结构、多个光栅结构。
可选地，所述二维衍射光栅结构的折射率大于所述波导层的折射率。
可选地，所述二维衍射光栅结构包括第一子光栅和环绕所述第一子光栅的多个第二子光栅，所述第一子光栅在所述波导层上的正投影为圆形，所述多个第二子光栅在所述波导层上的正投影为与所述圆形同心且半径不同的环形。
可选地，所述第一子光栅和至少一个所述第二子光栅的周期、线宽、高度不完全相同；至少两个所述第二子光栅的周期、线宽、高度不完全相同。
可选地，在所述第一子光栅的任一个周期内，所述第一子光栅包括多个第一子结构；
各所述第一子结构的线宽不相等、高度也不相等；或，各所述第一子结构的线宽相等、高度不相等；或，各所述第一子结构的线宽不相等、高度相等。
可选地，在每一所述第二子光栅的任一个周期内，每一第二子光栅包括多个第二子结构；
各所述第二子结构的线宽不相等、高度也不相等；或，各所述第二子结 构的线宽相等、高度不相等；或，各所述第二子结构的线宽不相等、高度相等。
可选地，所述二维衍射光栅结构与所述第一表面接触；所述光源与所述第一表面具有设定距离。
可选地，所述二维衍射光栅结构与所述第二表面接触；所述取光结构与所述二维衍射光栅结构在所述波导层上的正投影互不重叠。
可选地，所述光源与所述第一表面接触。
可选地，所述光源为单色光源；
所述面光源还包括：位于所述面光源出光侧的单色光转换层；
所述单色光转换层用于将所述光源出射的单色光转换为白光。
可选地，所述单色光转换层包括下列之一或其组合：荧光膜层、量子点膜层。
可选地，还包括：位于所述单色光转换层远离所述波导层一侧的反射层。
本公开实施例还提供了一种显示装置，包括本公开实施例提供的面光源。
附图说明
图1为单个LED光源的光场分布呈现琅勃曲线的分布图；
图2至图7分别为本公开一些实施例提供的面光源的结构示意图；
图8为本公开一些实施例提供的面光源中二维衍射光栅结构的结构示意图；
图9为本公开一些实施例提供的二维衍射光栅结构的俯视结构示意图；
图10为本公开一些实施例提供的二维衍射光栅结构的优化流程示意图；
图11为本公开一些实施例提供的LED光源的光场尺寸示意图；
图12为本公开一些实施例提供的第一子光栅沿平行于波导层方向上的截面示意图；
图13为图12沿AA’的截面示意图；
图14为本公开一些实施例提供的第一子光栅沿其直径的截面示意图；
图15为本公开一些实施例提供的第一子光栅沿其直径的截面示意图；
图16为图9所示的二维衍射光栅结构沿半径方向截面示意图；
图17为本公开一些实施例提供的主光线角与光耦合效率曲线图；
图18为本公开一些实施例提供的在任一子光栅的一个周期内二维衍射光栅结构直径方向的截面示意图；
图19为本公开一些实施例提供的二维衍射光栅结构每一子光栅的光耦合效率的部分优化结果图；
图20为本公开一些实施例提供的显示装置的结构示意图；
图21为本公开一些实施例提供的二维衍射光栅结构对两个偏振方向的光线具有高耦合效率的原理示意图。
具体实施方式
由于单个LED光源的光场分布呈现琅勃曲线分布且大致相同，如图1所示，其主要能量集中在-60°～60°，在0°能量最强。LED的这一特点将导致过热(hot-spot)现象，即使用点光源LED作为光源的画面会出现明显的亮暗交替现象，进而影响显示的效果。
目前为了增强LCD的显示能力，避免出现hot-spot现象，提高人眼观看图像的舒适度，直下式背光结构中通过增大LED之间的纵向混光距离，以及减少LED之间的间距来提高直下式背光结构的出光均匀性。相关技术中的直下式背光结构中相邻的LED光源之间的纵向混光距离在2毫米(mm)～22mm范围。并且由于LED之间的水平间距很小，因而直下式背光结构中LED的使用数目非常庞大，约为几万颗。
即通过增大LED之间的纵向混光距离及减少LED间距来提高直下式背光结构均匀性的做法，不仅会大大增加直下式背光结构的整体厚度，同时增加了直下式背光结构中LED的使用数目，进而增加成本，造成了一定的LED使用数量冗余。
本公开实施例提供了一种面光源及显示装置，用以减少面光源即直下式 背光结构的厚度，且减少面光源中LED的使用数目，以降低成本。
本公开实施例提供的一种面光源，如图2至图7所示，包括：
波导层1，波导层1具有相对的第一表面11和第二表面12；波导层1的第二表面12包括取光结构2，取光结构2用于均匀导出在波导层1全反射传播的光线；
多个光源3，各光源3位于第一表面11一侧；
多个二维衍射光栅结构4，各二维衍射光栅结构4与光源3一一对应，各二维衍射光栅结构4位于对应的光源3与取光结构2之间，各二维衍射光栅结构4与波导层1接触，二维衍射光栅结构4用于将对应的光源3发出的光线导入波导层1。
具体地，在本公开实施例提供的上述面光源中，由于光在波导层1全反射传输，使从取光结构2出射的光能量及方向均匀分布，可以使面光源中不存在混光距离，不存在点光源均匀性难控制的问题，因此，无需通过增加光源3的纵向混光距离来实现均匀出光，从而可以减少面光源的整体厚度，降低生产成本。并且，通过面光源出射的光线的均匀性由取光结构2控制，这样，单个光源1就可以提供单块区域的整体背光，从而可以很大比例减少面光源中的光源1的数目，从而可以降低成本。
可选地，在本公开实施例提供的上述面光源中，如图2和3所示，二维衍射光栅结构4可以位于波导层1的第一表面11，即二维衍射光栅结构4与第一表面11接触，此时，光源3需要与第一表面11具有设定距离。
可选地，在本公开实施例提供的上述面光源中，如图4至图7所示，二维衍射光栅结构4也可以位于波导层1的第二表面12，即二维衍射光栅结构4与第二表面12接触，此时，取光结构2与二维衍射光栅结构4在波导层1上的正投影一般互不重叠；即当取光结构2与二维衍射光栅结构4同时位于波导层1的第二表面12时，设置二维衍射光栅结构4的位置可以不设置取光结构2。
可选地，在本公开实施例提供的上述面光源中，当二维衍射光栅结构4 与第二表面12接触时，如图5和图7所示，光源1可以与第一表面11接触，这样可以进一步降低面光源的厚度。
可选地，在本公开实施例提供的上述面光源中，二维衍射光栅结构4与波导层1可以均采用透明材料，例如，二维衍射光栅结构4的材料可以选则氮化硅(Si 3N 4)，波导层1的材料可以选择氧化铟锡(ITO)或Si 3N 4等，在此不做限定。
可选地，在本公开实施例提供的上述面光源中，二维衍射光栅结构4的折射率一般大于波导层1的折射率。这样可以保证通过面光源的光具有较高的光耦合效率，从而可以提高光源1的利用率，节约能源。
需要说明的是，在本公开实施例提供的上述面光源中，波导层1的折射率需要大于与除了二维衍射光栅结构4和取光结构2之外的与波导层1接触的介质的折射率，从而实现光在波导层1全反射传输。例如，如图2所示，与波导层1接触的介质为空气，即波导层1的折射率需要大于空气的折射率。
可选地，在本公开实施例提供的上述面光源中，取光结构2可以包括下列之一或其组合：多个网点结构、多个光栅结构。具体地，取光结构2可以是单独的结构，也可以是直接做在波导层1上，例如网点结构可以直接坐在波导层1的第二表面12上，光栅结构可以独立于波导层1，在此不做限定。
需要说明的是，在本公开实施例提供的上述面光源中，光源1与取光结构2的距离不同，光到达取光结构2的光强也不相同，需要根据到达取光结构2的光强对网点结构的大小及疏密排布进行设计，或根据到达取光结构2的光强对光栅结构的周期、占空比以及高度进行设计。
可选地，在本公开实施例提供的上述面光源中，网点结构的典型尺寸(网点结构的长或宽)在0.1～1毫米范围。具体地，可以设置二维衍射光栅结构4在波导层1表面不同位置的衍射效率不同，靠近光源1的位置的二维衍射光栅结构4的衍射效率小于远离光源1位置的衍射效率，从而使得从取光结构2出射的光线能量均匀分布。
可选地，在本公开实施例提供的上述面光源中，如图2至图7所示，光 源3在波导层1的正投影一般位于对应的二维衍射光栅结构4在波导层1的正投影中心位置处。
可选地，在本公开实施例提供的上述面光源中，二维衍射光栅结构4例如可以是如图8所示的结构，二维衍射光栅结构4包括多个子结构41，二维衍射光栅结构4沿其所在的直角坐标平面的X方向和Y方向，都具有周期性，即子结构41沿X方向和Y方向周期性排布。图4中a、e的长度分别对应于二维衍射光栅结构4沿X方向、Y方向的线宽，c的长度对应于二维衍射光栅结构4的高度(当每个子结构41呈台阶状时，二维衍射光栅结构4就包括多个高度参数)，b、d的长度分别对应于二维衍射光栅结构4沿X方向、Y方向的周期。a、e的长度可以相等也可以不相等，b、d的长度可以相等不相等，即二维衍射光栅结构4沿X方向、Y方向的线宽和周期相等。
并且，相邻的两个子结构41之间存在间隙，当然二维衍射光栅结构4也可以设置成相邻的两个子结构41之间不存在间隙的结构，即二维衍射光栅结构4在X方向、Y方向的线宽等于二维衍射光栅结构4在X方向、Y方向的周期。需要说明的是，如图4所示的二维衍射光栅结构4，子结构41沿X方向和Y方向周期性排布，即一个子结构41与二维衍射光栅结构4的一个周期相对应，当然，二维衍射光栅结构4中，与二维衍射光栅结构4的一个周期相对应也可以为其他形状的结构，在此不做限定。
可选地，本公开实施例提供的上述面光源中，如图9所示，二维衍射光栅结构4可以包括第一子光栅42和环绕第一子光栅42的多个第二子光栅43，第一子光栅42在波导层1上的正投影为圆形，多个第二子光栅43在波导层1上的正投影为与圆形同心且半径不同的环形。图9是以二维衍射光栅结构4包括三个子光栅为例进行说明的。当然，本公开实施例提供的上述面光源中的二维衍射光栅结构4也可以为其他形状，第一子光栅和第二子光栅的也可以为其他形状，在此不做限定。
需要说明的是，本公开实施例提供的上述面光源中的二维衍射光栅结构4的结构，可以通过严格耦合波理论以及相关算法(例如模拟退火算法)优化 得到。如图10所示，当光源3为LED光源，对将LED的发散角度为-60°～60°的光束高效率耦合进入波导层1进行全反射传输的二维衍射光栅结构4的优化，具体包括以下步骤：
S101、确定光源3在波导层1下表面的光场尺寸；
从光学视场角(光源3的有效出光范围)出发，量化LED在波导层1特定位置处的光线角度范围，如图11所示，LED光源3设置在波导层1的下方，由于LED光源3出射光分布对称，因此图11为LED光源3右半部分光场示意图，对于距离波导层1的距离为d的光源3来说，由于其主要能量集中在0°～60°范围内，因此光源3在波导层1下表面的光场尺寸L可以确定：
L＝d/tan(30°)；
S102、将波导层1下表面L采样分为若干等间隔的小区域P，使得光源3经过每个小区域P的光线的光耦合效率满足预设条件。
图11中的每个小区域P对应于二维衍射光栅结构4的每一子光栅，由于LED光源3的尺寸是确定的，那么由LED光源3发出的光束经过采样的小区域P的角度范围是确定的，即LED光源3经过每个小区域P的视场角是确定的。
在本公开实施例提供的上述面光源中，为实现高耦合效率，经过每个小区域P的光线角度分布范围，例如可以限制在5°以内。需要说明的是，经过每个小区域P的光线角度分布范围，可以根据LED光源3的尺寸以及LED光源3与波导层1之间的距离确定。优化得出每一子光栅的结构，使得由光源3发出的、到达二维衍射光栅结构4后再次出射的光，在波导层1全反射传输，并且对每个采样小区域内的主光线耦合效率最高，同时保证每个采样区域的边缘光线的耦合效率尽量高。这样，通过上述从视场角度出发量化LED光源3的光线角度范围的方式，便可以优化得出二维衍射光栅结构4中每一子光栅的结构。
具体地，光耦合效率满足的预设条件可以根据实际需要进行设置，本公开实施例选择的光耦合效率的预设条件为：使得由光源3发出的、到达二维 衍射光栅结构4后再次出射的光的光耦合效率大于60％。
根据上述对二维衍射光栅结构4的优化思路，二维衍射光栅结构4在波导层1表面的尺寸与LED光源3的整个光场相对应，可选地，二维衍射光栅结构4满足如下条件：
Figure PCTCN2018090697-appb-000003
其中，D为二维衍射光栅结构4的直径，d为光源3与波导层1靠近二维衍射光栅结构4的表面之间的距离。
可选地，本公开实施例提供的上述面光源中，第一子光栅42和至少一个第二子光栅43的周期、线宽、高度不完全相同，至少两个第二子光栅43的周期、线宽、高度也不完全相同。由于光栅对入射光的角度比较敏感，将子光栅设置为具有不同的周期、线宽和高度，从而可以实现一个二维衍射光栅结构4对多个角度的入射光的耦合效率较高，进一步提高光源3的利用率。
可选地，本公开实施例提供的光场调制层中，在第一子光栅42的任一个周期内，第一子光栅42可以包括多个第一子结构421；具体地，例如图5所示的二维衍射光栅结构4中，第一子光栅42沿平行于波导层1方向上的截面图如图12所示，第一子光栅42沿图12中AA’的截面图如图13所示，第一子光栅42的每一个周期42’包括三个环形的第一子结构421(第一子光栅42圆心对应的第一子结构421可以看作是内环半径为0的环形)；
各第一子结构421的线宽可以不相等、高度也可以不相等，图12和13所示的第一子光栅42的任一周期内的三个第一子结构421的线宽f1、高度f2均不相等。
或者，各第一子结构421的线宽相等、高度不相等，即第一子光栅42沿其直径的截面图也可以如图14所示，任一周期42’内的三个第一子结构421的线宽f1相等，但高度f2不相等。
或者，各第一子结构421的线宽不相等、高度相等，即第一子光栅42沿其直径的截面图如图15所示，每一个周期42’包括环形的第一子结构421的 线宽f1和高度f2均相等，可以理解的是，当第一子结构421的线宽f1和高度f2均相同时，相邻的第一子结构421之间需要存在间隙。
同理，可选地，本公开实施例提供的光场调制层中，在每一第二子光栅43的任一个周期内，每一第二子光栅43可以包括多个第二子结构431；
各第二子结构431的线宽可以不相等、高度也可以不相等；或，各第二子结构431的线宽相等、高度不相等；或，各第二子结构431的线宽不相等、高度相等。
具体地，例如当不同子光栅的周期、线宽、高度均不相同、在波导层1上的正投影如图9所示的二维光栅，沿其直径方向的截面图如图16所示，第一子光栅42和两个第二子光栅43均包括至少两个周期，第一子光栅42和第二子光栅43在一个周期42’(43’)内包括三个线宽f1和高度f2均不相等的第一子结构421和第二子结构431。
根据上述设计方式，选择基于模拟退火算法的耦合波算法，以全局的形式优化二维衍射光栅结构4，具体参数如下：LED光源3的尺寸为0.2mm、d＝2mm、波导层1的折射率为1.5、二维衍射光栅结构4的折射率为2、采取等间隔量化L(L＝3.5mm)以及小间隔区域数目为19个，优化得到通过每一子光栅的主光线角(即主光线入射到每个小区域P的入射角)对应的光耦合效率图如图17所示。从图17中可以看出，对于每一子光栅，主光线的光耦合效率都大于60％，相应的子光栅的结构参数表1所示，优化得到的在任一子光栅的一个周期内，沿二维衍射光栅结构4直径方向的截面图如图18所示，包括四个线宽f1不相等，高度f2也不相等第一子结构421(第二子结构431)。
相应地，二维衍射光栅结构4每一子光栅的光耦合效率的部分优化结果如图19所示，图19中的I角度代表入射到光栅的光线的入射角，T代表光栅的透过效率，R代表光栅的反射效率，T、R之后的数字代表衍射级数，图19中黑色粗线框圈出的部分代表角度满足全反射条件的衍射角度，通过效率一列可以看出，优化得到的二维衍射光栅结构4可以将绝大多数的光衍射偏折在全反射角度上，实现在波导层1中耦合，即发生全反射传输。
需要说明的是，在对二维衍射光栅结构4优化的过程中，在将光场尺寸L划分成若干小区域P时，每个小区域P的尺寸也可以不相等，这样对应的任一子光栅沿二维衍射光栅结构4半径方向上的宽度也不相等。优化得到的二维衍射光栅结构4，只要使得通过二维衍射光栅结构4进入波导层1的光在波导层1全反射传输并且具有较高的耦合效率即可，每一子光栅一个周期内的还可以包括线宽相等但高度不相等的子结构，或者包括高度相等但线宽不相等的子结构。
表1
小区域P序号 周期(μm) 最小线宽(nm) 主光线入射角度(°)
1 1 180 0
2 0.9 183 2.7
3 0.95 145 11.3
4 1 56 17
5 1 184 22
6 1.05 91 27
7 1.1 94 31
8 1.1 64 35
9 1.1 73 39
10 1.1 73 42
11 1.1 80 45
12 1.1 80 48
13 1.1 80 50
14 1.1 80 52
15 1.1 80 55
16 1.1 80 56
17 1.1 105 58
18 1.1 105 60
19 1.1 105 61
为了保证从LED光源3出射的光经过二维衍射光栅结构4耦合进入波导层1进行全反射传输的光不被二维衍射光栅结构4破坏，可选地，本公开实施例提供的上述面光源中，波导层1可以满足如下条件：
Figure PCTCN2018090697-appb-000004
其中，h为波导层1的厚度，θ为由光源3发出的、到达二维衍射光栅结构4后入射到波导层1的光的入射角。需要说明的是，进入波导层1后的光在波导层1和二维衍射光栅结构4的界面发生衍射便会破坏光的全反射过程，因此波导层1的厚度满足上述条件，从二维衍射光栅结构4中心位置衍射进入波导层1内的光在全反射传输过程中，不会被二维衍射光栅结构4的衍射调制而破坏全反射传输条件。
可选地，本公开实施例提供的上述面光源中，波导层1的厚度例如可以为2微米，当然波导层1的厚度也可以增加到几十微米，在此不做限定。
可选地，本公开实施例提供的上述面光源中，光源3可以是LED，LED的芯片例如可以选择无机半导体材料或有机发光材料，在此不做限定。
可选地，本公开实施例提供的上述面光源中，光源3可以为单色光源。例如，可以选择出光颜色为蓝色的LED，也可以选择出光波段在紫外光范围的LED，当然也可以选择出光颜色为其他颜色的单色光源，在此不做限定。
可选地，在本公开实施例提供的上述面光源中，如图3至图7所示，还可以包括：位于面光源出光侧的单色光转换层5，单色光转换层5用于将光源3出射的光转换为白光。
可选地，本公开实施例提供的上述面光源中，单色光转换层5可以包括下列之一或其组合：荧光膜层、量子点膜层。
具体地，荧光膜层例如可以选择掺铈钇铝石榴石(Y 3Al 5O 12:Ce^3+)；量子点膜层包括量子点材料，量子点是由有限数目的原子组成，其三个维度尺寸均在纳米数量级。量子点一般为球形或类球形，通常由元素周期表中IIB～ⅥA或IIIA～VA的元素组成的半导体材料制成，也可以由两种或两种以上的 半导体材料组成，IIB～ⅥA的元素组成的半导体材料例如可以是硫化镉(CdS)、硒化镉(CdSe)、碲化镉(CdTe)、硒化锌(ZnSe)等，IIIA～VA的元素组成的半导体材料例如可以是磷化铟(InP)、砷化铟(InAs)等，量子点的稳定直径在2～20nm的纳米粒子。
可选地，在本公开实施例提供的上述面光源中，如图3至图7所示，还可以包括：位于单色光转换层5远离波导层1一侧的反射层6。
具体地，由于利用率二维衍射光栅结构4对LED光源3出射的光线进行耦合，将不可避免地有反射衍射损失，因此设置反射层6可以使反射衍射损失的光线重新被利用。可选地，反射层6可以采用金属膜层，金属材料例如可以选择铝或银，反射层也可以采用多层介质膜或者其他具有反射光线作用的材料。
具体地，在本公开实施例提供的上述面光源中，如图3所示，LED光源3可以设置在反射层6上、且位于波导层1和反射层6之间，二维衍射光栅结构4设置在波导层1靠近LED光源3的第一表面11，作为取光结构2的网点结构设置在波导层1远离LED光源3的第二表面12，作为单色光转换层5的荧光膜层位于取光结构2之上。
具体地，在本公开实施例提供的上述面光源中，如图4所示，二维衍射光栅结构4与取光结构2可以均设置在波导层1远离LED光源3的第一表面11，此时，LED光源3与波导层1之间的距离大约零，在波导层1设置有二维衍射光栅结构4的位置不设置取光结构2，二维衍射光栅结构4为反射型光栅。在如图4所示的面光源的基础上，也可以使得LED光源3直接与波导层1靠近LED光源3的第一表面11接触，如图5所示，即LED光源3与波导层1之间的距离为零，相比于图4所示的面光源，图5所示的面光源可以进一步减小面光源的厚度。
具体地，在本公开实施例提供的上述面光源中，如图6所示，LED光源3也可以设置在荧光膜层5之下、且位于波导层1和荧光膜层5之间朝向波导层1出光，二维衍射光栅结构4和取光结构2均设置在波导层1远离LED光 源3的第二表面12。此时，LED光源3与波导层1之间的距离大约零，在波导层1设置有二维衍射光栅结构4的位置不设置取光结构2，二维衍射光栅结构4为反射型光栅。在如图6所示的面光源的基础上，也可以使LED光源3直接与波导层1靠近LED光源3的第一表面11接触，如图7所示，即LED光源3与波导层1之间的距离为零，相比于图6所示的面光源，图7所示的面光源可以进一步减小面光源的厚度。
需要说明的是，本公开实施例提供的上述面光源中，光源3与波导层1的距离对面光源的出光均匀性并无影响，光源3与波导层1的距离仅影响面光源的光耦合效率，原则上，光源3与波导层1的距离越大，面光源的光耦合效率越高，在对面光源进行设计时，需要综合面光源的厚度和面光源所需要实现的光耦合效率来决定光源3与波导层1之间的距离。可选地，本公开实施例提供的上述面光源中，光源3与波导层1的距离大于等于零。
基于同一发明构思，本公开实施例还提供的一种显示装置，包括本公开实施例提供的上述面光源。
例如，本公开实施例提供的上述显示装置可以是液晶显示装置。
如图20所示，本公开实施例提供的显示装置包括面光源10、位于面光源10之上的下偏光片层20、位于下偏光片层20之上的显示面板30以及位于显示面板30之上的上偏光片层40，其中，面光源10可以是本公开实施例提供的任一种面光源。
需要说明的是，当采用本公开实施例提供的如图10所示的方法对二维衍射光栅结构4进行优化的过程中，只能针对光线的一个偏振方向进行优化，即只有一个偏振方向的光线被二维衍射光栅结构4调制后具有较高的光耦合效率。可选地，本公开实施例提供的上述面光源中，二维衍射光栅结构4使得由光源3出射的任一偏振方向的光线的光耦合效率满足预设条件。光耦合效率满足的预设条件例如可以是光耦合效率大于60％。例如，在针对光线的第一偏振方向进行优化得到第一二维衍射光栅结构4，之后再对光线的第二偏振方向进行优化，光线的第一偏振方向与光线的第二偏振方向不同，得到第 二二维衍射光栅结构4，之后对优化得到的第一二维衍射光栅结构4和第二二维衍射光栅结构4再次进行优化(例如调整光栅二维方向不同位置的高度和线宽)，叠加形成一个二维衍射光栅结构4，该二维衍射光栅结构4使得第一偏振方向和第二偏振方向的光线的光耦合效率均大于60％，即该二维衍射光栅结构4使得由光源3出射的两个偏振方向的光线都具有较高的光耦合效率，进一步提高面光源中光源的利用率。
对于如图20所示的显示装置，其面光源中的二维衍射光栅结构4对两个偏振方向的光线具有高耦合效率的原理示意图如图21所示，二维衍射光栅结构4由优化得到的第一二维衍射光栅结构和第二二维衍射光栅结构再次优化叠加形成，需要说明的是，图21中二维衍射光栅结构4为沿平行于波导层1所在平面的的截面示意图，二维衍射光栅结构4沿Y方向的截面4’对应的结构和二维衍射光栅结构4沿X方向的截面4”对应的结构分别使得两个偏振方向的光的光耦合效率满足预设条件，双向箭头代表偏振方向平行于纸面的光线的偏振方向，实心圆点代表偏振方向垂直于纸面的光线的偏振方向。二维衍射光栅结构4沿Y方向的截面4’对应的结构对于偏振方向与实心圆点对应的方向一致的光线的反射较少且光耦合效率较高，而对于偏振方向与双向箭头对应的方向一致的光的反射较多，二维衍射光栅结构4沿X方向的截面4”对应的结构对于偏振方向与双向箭头对应的方向一致的光线的反射较少且光耦合效率较高，而对于偏振方向与实心圆点对应的方向一致的光的反射较多，图中角a、b的度数大于波导层满足的全反射条件时的全反射临界角，因此与二维衍射光栅结构4沿Y方向的截面4’对应的结构和二维衍射光栅结构4沿X方向的截面4”对应的结构对应的偏振方向的光线，进入波导层1可以进行全反射传输。
需要说明的是，本公开实施例提供的上述显示装置，可以采用局部背光调节(Local diming)技术来减少功耗，提高成像对比度，增加灰阶数、及减少残影等。将显示装置的面光源划分成多个小区域(Block)；当显示装置工作时，根据相应小区域对应显示内容的灰度，来调整背光的明暗对比度；以此 达到节能、增加画质的目的。
综上，本公开实施例提供的面光源及显示装置，由于光在波导层全反射传输，使得面光源不存在混光距离，不存在面光源点光源均匀性难控制的问题，无需通过增加光源的纵向混光距离来实现均匀出光，从而可以减少面光源的整体厚度，降低生产成本。并且通过面光源出射的光线的均匀性由取光结构控制，这样，单个光源就可以提供单块区域的整体背光，从而可以很大比例减少面光源中的光源的数目，从而可以降低成本。
显然，本领域的技术人员可以对本公开进行各种改动和变型而不脱离本公开的精神和范围。这样，倘若本公开的这些修改和变型属于本公开权利要求及其等同技术的范围之内，则本公开也意图包含这些改动和变型在内。

Claims (18)

  1. 一种面光源，其中，包括：
    波导层，所述波导层具有相对的第一表面和第二表面；所述波导层的所述第二表面包括取光结构，所述取光结构用于均匀导出在所述波导层全反射传播的光线；
    多个光源，各所述光源位于所述第一表面一侧；
    多个二维衍射光栅结构，各所述二维衍射光栅结构与所述光源一一对应，各所述二维衍射光栅结构位于对应的所述光源与所述取光结构之间，各所述二维衍射光栅结构与所述波导层接触，所述二维衍射光栅结构用于将对应的所述光源发出的光线导入所述波导层。
  2. 根据权利要求1所述的面光源，其中，所述光源在所述波导层的正投影位于对应的所述二维衍射光栅结构在所述波导层的正投影中心位置处。
  3. 根据权利要求1所述的面光源，其中，所述二维衍射光栅结构满足如下条件：
    Figure PCTCN2018090697-appb-100001
    其中，D为所述二维衍射光栅结构的直径，d为所述光源与所述波导层靠近所述二维衍射光栅结构一侧表面之间的距离。
  4. 根据权利要求1所述的面光源，其中，所述波导层满足如下条件：
    Figure PCTCN2018090697-appb-100002
    其中，h为所述波导层的厚度，θ为入射至所述波导层的光线入射角，D为所述二维衍射光栅结构的直径。
  5. 根据权利要求4所述的面光源，其中，所述波导层的厚度大于等于2微米。
  6. 根据权利要求1所述的面光源，其中，所述取光结构包括下列之一或其组合：多个网点结构、多个光栅结构。
  7. 根据权利要求1所述的面光源，其中，所述二维衍射光栅结构的折射 率大于所述波导层的折射率。
  8. 根据权利要求1所述的面光源，其中，所述二维衍射光栅结构包括第一子光栅和环绕所述第一子光栅的多个第二子光栅，所述第一子光栅在所述波导层上的正投影为圆形，所述多个第二子光栅在所述波导层上的正投影为与所述圆形同心且半径不同的环形。
  9. 根据权利要求8所述的面光源，其中，所述第一子光栅和至少一个所述第二子光栅的周期、线宽、高度不完全相同；至少两个所述第二子光栅的周期、线宽、高度不完全相同。
  10. 根据权利要求9所述的面光源，其中，在所述第一子光栅的任一个周期内，所述第一子光栅包括多个第一子结构；
    各所述第一子结构的线宽不相等、高度也不相等；或，各所述第一子结构的线宽相等、高度不相等；或，各所述第一子结构的线宽不相等、高度相等。
  11. 根据权利要求9-10任一项所述的面光源，其中，在每一所述第二子光栅的任一个周期内，每一第二子光栅包括多个第二子结构；
    各所述第二子结构的线宽不相等、高度也不相等；或，各所述第二子结构的线宽相等、高度不相等；或，各所述第二子结构的线宽不相等、高度相等。
  12. 根据权利要求1所述的面光源，其中，所述二维衍射光栅结构与所述第一表面接触；所述光源与所述第一表面具有设定距离。
  13. 根据权利要求1所述的面光源，其中，所述二维衍射光栅结构与所述第二表面接触；所述取光结构与所述二维衍射光栅结构在所述波导层上的正投影互不重叠。
  14. 根据权利要求13所述的面光源，其中，所述光源与所述第一表面接触。
  15. 根据权利要求1～14任一项所述的面光源，其中，所述光源为单色光源；
    所述面光源还包括：位于所述面光源出光侧的单色光转换层；
    所述单色光转换层用于将所述光源出射的单色光转换为白光。
  16. 根据权利要求15所述的面光源，其中，所述单色光转换层包括下列之一或其组合：荧光膜层、量子点膜层。
  17. 根据权利要求1～14任一项所述的面光源，其中，还包括：位于所述单色光转换层远离所述波导层一侧的反射层。
  18. 一种显示装置，其中，包括权利要求1～17任一项所述的面光源。
PCT/CN2018/090697 2017-08-01 2018-06-11 面光源及显示装置 WO2019024605A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US16/329,456 US11256010B2 (en) 2017-08-01 2018-06-11 Area light source and display device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201710647865.0A CN107193070B (zh) 2017-08-01 2017-08-01 一种光场调制层、背光结构及显示装置
CN201710647865.0 2017-08-01

Publications (1)

Publication Number Publication Date
WO2019024605A1 true WO2019024605A1 (zh) 2019-02-07

Family

ID=59884986

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/090697 WO2019024605A1 (zh) 2017-08-01 2018-06-11 面光源及显示装置

Country Status (3)

Country Link
US (1) US11256010B2 (zh)
CN (1) CN107193070B (zh)
WO (1) WO2019024605A1 (zh)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107193070B (zh) 2017-08-01 2020-07-28 京东方科技集团股份有限公司 一种光场调制层、背光结构及显示装置
CN107608134B (zh) * 2017-09-27 2019-07-12 京东方科技集团股份有限公司 导光结构、直下式背光模组及显示面板
CN108050439B (zh) * 2018-01-03 2020-02-28 京东方科技集团股份有限公司 背光模组及显示装置
CN109581669B (zh) * 2019-01-23 2021-07-13 歌尔股份有限公司 投影光路及头戴显示设备
CN109856861B (zh) 2019-04-02 2021-04-16 京东方科技集团股份有限公司 一种显示面板、显示装置，以及显示面板的驱动方法
CN110471210B (zh) 2019-08-22 2022-06-10 京东方科技集团股份有限公司 彩膜基板、显示面板及显示装置
CN111045250A (zh) * 2019-12-06 2020-04-21 深圳市华星光电半导体显示技术有限公司 光转换结构及显示装置
WO2021114526A1 (zh) * 2019-12-13 2021-06-17 海信视像科技股份有限公司 一种显示装置
WO2023070478A1 (zh) * 2021-10-28 2023-05-04 京东方科技集团股份有限公司 发光基板及其制备方法和发光装置
CN113985519B (zh) * 2021-12-24 2022-04-08 深圳铅笔视界科技有限公司 一种光波导器件、显示装置和显示设备

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06224851A (ja) * 1993-01-22 1994-08-12 Nippon Sheet Glass Co Ltd 機能性光カプラ
CN1116719A (zh) * 1993-10-18 1996-02-14 松下电器产业株式会社 衍射光学器件
CN1959490A (zh) * 2005-11-02 2007-05-09 群康科技(深圳)有限公司 背光模组及采用该背光模组的液晶显示装置
KR20080028133A (ko) * 2006-09-26 2008-03-31 주식회사 영실업 회절격자가 구비된 도광체 및 이를 이용한 면광원장치
CN105549150A (zh) * 2016-03-04 2016-05-04 东南大学 一种全息波导显示装置
CN107193070A (zh) * 2017-08-01 2017-09-22 京东方科技集团股份有限公司 一种光场调制层、背光结构及显示装置

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100419528C (zh) * 2003-08-14 2008-09-17 鸿富锦精密工业（深圳）有限公司 背光模组及其导光板
CN100405154C (zh) * 2003-12-08 2008-07-23 鸿富锦精密工业（深圳）有限公司 背光模组
CN100376958C (zh) 2004-02-19 2008-03-26 鸿富锦精密工业（深圳）有限公司 导光板及背光模组
CN100492120C (zh) * 2005-12-16 2009-05-27 群康科技(深圳)有限公司 背光模组及其导光板
KR101272054B1 (ko) * 2008-12-26 2013-06-05 엘지디스플레이 주식회사 액정표시장치
US8585268B2 (en) * 2011-10-21 2013-11-19 Ergophos, Llc Light-guide panel for display with laser backlight
KR101657954B1 (ko) * 2014-02-05 2016-09-21 삼성디스플레이 주식회사 백라이트 어셈블리 및 이를 포함하는 표시 장치
CN107624163B (zh) * 2015-05-09 2020-11-06 镭亚股份有限公司 基于颜色扫描光栅的背光体及使用该背光体的电子显示器
CN106526738B (zh) * 2016-12-28 2019-11-22 武汉华星光电技术有限公司 一种导光板及制作方法、背光模组、液晶显示模组

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06224851A (ja) * 1993-01-22 1994-08-12 Nippon Sheet Glass Co Ltd 機能性光カプラ
CN1116719A (zh) * 1993-10-18 1996-02-14 松下电器产业株式会社 衍射光学器件
CN1959490A (zh) * 2005-11-02 2007-05-09 群康科技(深圳)有限公司 背光模组及采用该背光模组的液晶显示装置
KR20080028133A (ko) * 2006-09-26 2008-03-31 주식회사 영실업 회절격자가 구비된 도광체 및 이를 이용한 면광원장치
CN105549150A (zh) * 2016-03-04 2016-05-04 东南大学 一种全息波导显示装置
CN107193070A (zh) * 2017-08-01 2017-09-22 京东方科技集团股份有限公司 一种光场调制层、背光结构及显示装置

Also Published As

Publication number Publication date
CN107193070A (zh) 2017-09-22
CN107193070B (zh) 2020-07-28
US20200166680A1 (en) 2020-05-28
US11256010B2 (en) 2022-02-22

Similar Documents

Publication Publication Date Title
WO2019024605A1 (zh) 面光源及显示装置
US11237429B2 (en) Light guiding assembly and fabricating method thereof, backlight module and display device
JP6389570B2 (ja) 量子ドットバックライトモジュール及び表示装置
US8079743B2 (en) Display backlight with improved light coupling and mixing
TWI541472B (zh) 背光模組
WO2019062137A1 (zh) 导光结构、直下式背光模组及显示面板
US11391877B2 (en) Backlight source and manufacturing method thereof, and display device
TWI408463B (zh) 光源模組及照明裝置
US9618681B2 (en) Quantum dot backlight module and display device
WO2018166154A1 (zh) 一种光源器件及显示装置
TW201303362A (zh) 光控制鏡片及其光源裝置
KR102411120B1 (ko) 표시 장치
WO2021018219A1 (zh) 显示面板和显示装置
US20160320541A1 (en) Backlight module and display device
WO2019019598A1 (zh) 背光模组及其制作方法、显示装置以及导光装置
US20130163258A1 (en) Lens for uniform illumination
WO2019134562A1 (zh) 背光源及其制作方法、显示装置
WO2017118214A1 (zh) 光学调制器、背光源模组及显示装置
WO2019153791A1 (zh) 像素结构、显示面板、显示装置及显示方法
WO2019061779A1 (zh) 一种阵列基板、掩膜板及阵列基板制作方法
TWI506346B (zh) 散熱光學透鏡與使用該散熱光學透鏡的背光模組
TWI414835B (zh) 導光板及背光模組
Kim et al. Integration of prism sheet on quantum dot film with bridge patterns to enhance luminance of LED backlight unit
TWM555484U (zh) 具有量子點膜的光源模組
Hu et al. A method to design freeform lens for uniform illumination in direct-lit led backlight with high distance-height ratio

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18840247

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 03/06/2020)

122 Ep: pct application non-entry in european phase

Ref document number: 18840247

Country of ref document: EP

Kind code of ref document: A1