CN113075816A - Backlight module and display device - Google Patents
Backlight module and display device Download PDFInfo
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- CN113075816A CN113075816A CN202110283685.5A CN202110283685A CN113075816A CN 113075816 A CN113075816 A CN 113075816A CN 202110283685 A CN202110283685 A CN 202110283685A CN 113075816 A CN113075816 A CN 113075816A
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- 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
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- 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
- G02B6/0033—Means for improving the coupling-out of light from the light guide
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- 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
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0055—Reflecting element, sheet or layer
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- 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
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
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- 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
- G02B6/0065—Manufacturing aspects; Material aspects
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- 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
- G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
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- 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
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- 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
- G02F1/1339—Gaskets; Spacers; Sealing of cells
- G02F1/13394—Gaskets; Spacers; Sealing of cells spacers regularly patterned on the cell subtrate, e.g. walls, pillars
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- 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
- G02F1/1343—Electrodes
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- Optics & Photonics (AREA)
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- Mathematical Physics (AREA)
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Abstract
The invention provides a backlight module and a display device, which comprise a light guide plate and a light source arranged on one side of the light guide plate, wherein the light guide plate comprises a first transparent substrate and a second transparent substrate which are oppositely arranged, and a polymer liquid crystal layer positioned between the first transparent substrate and the second transparent substrate, the thickness of the polymer liquid crystal layer is gradually increased from one side close to the light source to one side far away from the light source, and the light emitting intensity of the light guide plate is improved by increasing the number of the polymer liquid crystals far away from the light source, so that the light emitting uniformity of the light guide plate is realized.
Description
Technical Field
The application relates to the technical field of display, in particular to a backlight module and a display device.
Background
Liquid Crystal Display (LCD) devices are widely used in various electronic products, and a backlight module for providing a light source to the LCD panel is required because the LCD panel itself does not have a light emitting function.
At present, Polymer Dispersed Liquid Crystal (PDLC)/Polymer Network Liquid Crystal (PNLC) is used as a light guide plate of a backlight module, and through the conversion of the light guide plate between a transparent state and a fog state, the light emitting area of the backlight can be regulated by controlling the light emission of the LEDs in a partitioning manner, so that the display effect of high brightness and million-level contrast can be realized. However, since such a light guide plate is generally of a homogeneous structure, the effect of the light intensity component is weakened along with the increase of the propagation distance in the light transmission process, resulting in uneven light emission at a position far away from the LED light source.
Disclosure of Invention
In order to solve the above technical problem, an embodiment of the present invention provides a backlight module, including a light guide plate and a light source disposed at one side of the light guide plate, where the light guide plate includes a first transparent substrate and a second transparent substrate that are disposed opposite to each other, and a polymer liquid crystal layer disposed between the first transparent substrate and the second transparent substrate;
wherein the thickness of the polymer liquid crystal layer gradually increases from the side close to the light source to the side far away from the light source.
According to the backlight module provided by the embodiment of the invention, the light guide plate comprises a first transparent electrode and a second transparent electrode which are oppositely arranged between the first transparent substrate and the second transparent substrate, and the polymer liquid crystal layer is positioned between the first transparent electrode and the second transparent electrode.
According to the backlight module provided by the embodiment of the invention, the light guide plate comprises a plurality of supporting columns which are positioned between the first transparent substrate and the second transparent substrate and used for supporting the first transparent substrate and the second transparent substrate, and the heights of the supporting columns are gradually increased from one side close to the light source to one side far away from the light source.
According to the backlight module provided by the embodiment of the invention, the first transparent substrate is obliquely arranged relative to the second transparent substrate.
According to the backlight module provided by the embodiment of the invention, the first transparent substrate is arranged in parallel relative to the second transparent substrate, the light guide plate comprises a transparent film layer arranged on one side of the second transparent substrate facing the first transparent substrate, and the support column is arranged between the first transparent substrate and the transparent film layer.
According to the backlight module provided by the embodiment of the invention, the thickness of the transparent film layer is gradually reduced from the side close to the light source to the side far away from the light source.
According to the backlight module provided by the embodiment of the invention, the material of the transparent film layer comprises optical transparent adhesive.
According to the backlight module provided by the embodiment of the invention, the liquid crystal in the polymer liquid crystal layer is polymer dispersed liquid crystal or polymer network liquid crystal.
According to the backlight module provided by the embodiment of the invention, the backlight module further comprises a reflector plate positioned on one side of the light guide plate far away from the light-emitting surface.
On the other hand, the embodiment of the invention also provides a display device, which comprises a display panel and the backlight module.
The backlight module comprises a light guide plate and a light source arranged on one side of the light guide plate, wherein the light guide plate comprises a first transparent substrate and a second transparent substrate which are oppositely arranged, and a polymer liquid crystal layer positioned between the first transparent substrate and the second transparent substrate, the thickness of the polymer liquid crystal layer is gradually increased from one side close to the light source to one side far away from the light source, the light intensity of the polymer liquid crystal layer is improved by increasing the number of the polymer liquid crystals far away from the light source, and the light emission uniformity of the light guide plate is realized.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required in the embodiments are briefly described below. The drawings in the following description are only some embodiments of the present application, and it will be obvious to those skilled in the art that other drawings can be obtained from the drawings without inventive effort.
FIG. 1(a) is a schematic view illustrating light propagation of a conventional backlight module when a voltage is applied;
FIG. 1(b) is a schematic view illustrating light propagation of a conventional backlight module when no voltage is applied;
fig. 2 is a schematic structural diagram of a backlight module according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another backlight module according to an embodiment of the invention;
fig. 4 is a schematic structural diagram of another backlight module according to an embodiment of the invention;
fig. 5 is a schematic structural view illustrating a first transparent substrate and a second transparent substrate of a backlight module provided in an embodiment of the invention, which are arranged in parallel;
fig. 6 is a schematic structural view illustrating a first transparent substrate and a second transparent substrate of another backlight module according to an embodiment of the invention, which are disposed in parallel.
Detailed Description
Specific structural and functional details disclosed herein are merely representative and are provided for purposes of describing example embodiments of the present application. This application may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
In the description of the present application, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified. Furthermore, the term "comprises" and any variations thereof is intended to cover non-exclusive inclusions.
Directional phrases used in this disclosure, such as [ upper ], [ lower ], [ inner ], [ outer ], etc., refer only to the directions of the appended drawings. Accordingly, the directional terms used are used for explanation and understanding of the present invention, and are not used for limiting the present invention. In the drawings, elements having similar structures are denoted by the same reference numerals.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
For the convenience of understanding the technical solutions of the present invention, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
Fig. 1(a) and (b) are schematic diagrams illustrating light propagation corresponding to a backlight module with and without voltage applied thereto, respectively, where the backlight module 1 includes a light guide plate 20, the light guide plate 20 has a light incident surface, a first surface and a second surface opposite to the first surface, and the second surface is a light emitting surface; the light source 10 is disposed adjacent to the light incident side surface of the light guide plate 20, and the backlight module further includes a first transparent substrate 201 and a second transparent substrate 202 disposed opposite to each other, and a polymer liquid crystal layer 30 disposed between the first transparent substrate 201 and the second transparent substrate 202; optionally, the liquid crystal in the polymer liquid crystal layer 30 is a polymer dispersed liquid crystal or a polymer network liquid crystal.
The conventional liquid crystal display mode needs a polarizing film, so that the utilization rate of light is greatly reduced, which is a problem to be solved urgently. A polymer/liquid crystal composite film, which includes both polymer dispersed liquid crystal and polymer network liquid crystal, is the earliest proposed liquid crystal display technology without a polarizer. PDLC is prepared by mixing low molecular liquid crystal with prepolymer, carrying out polymerization reaction under certain conditions to form micron-sized liquid crystal particles 301 which are uniformly dispersed in a polymer network, and then obtaining a material with electro-optic response characteristics by utilizing dielectric anisotropy of liquid crystal molecules, wherein the PDLC has a structure that the liquid crystal is dispersed through polymers, namely the liquid crystal is separated in the polymer phase; PNLC has a structure in which liquid crystal is dispersed in a polymer network, and the liquid crystal in the polymer network has a continuous phase. As the polymer layer (polymer layer), a photo-setting resin can be used. For example, PNLC irradiates a solution in which a liquid crystal is mixed with a photopolymerizable polymer precursor (monomer) with ultraviolet light to polymerize the monomer to form a polymer, and disperses the liquid crystal in a network of the polymer.
For PNLC, in the off state, namely zero electric field, because the liquid crystal exists in a multi-domain state in the network, the distribution of the director of each liquid crystal domain is random, and the incident light is scattered at the interface of the domains due to the discontinuous change of the refractive index and is expressed as a scattering state; when voltage is applied to the PNLC, the electric field enables the directors in all the liquid crystal domains to be arranged into a single domain state along the direction of the electric field, the medium is uniform in refractive index for incident light, the PNLC is in the condition of light transmission under the application of enough voltage, and if the electric field is sufficiently large, the vertical transmittance reaches the maximum and is in a transparent state.
As shown in fig. 1(a) and (b), taking the polymer liquid crystal layer 30 as a polymer dispersed liquid crystal as an example, specifically, the polymer liquid crystal layer 30 includes liquid crystal particles 301 uniformly distributed therein, in fig. 1(a), after an external voltage is applied, the optical axes of the liquid crystal particles 301 in the polymer liquid crystal layer 30 are aligned perpendicular to the PDLC surface, i.e. aligned with the electric field direction, the effective refractive index of the liquid crystal particles 301 is substantially matched with the refractive index of the polymer, no obvious interface is formed, a substantially uniform medium is formed, so that the incident light is not scattered, the polymer liquid crystal layer 30 is in a transparent state, the LED light incident from the side surface is totally reflected in the polymer liquid crystal layer 30 and is not emitted from the light emitting surface of the light guide plate 20, and the light guide plate 20 is in a dark state.
Under the condition of no external voltage, as shown in fig. 1(b), the optical axis orientations of the liquid crystal particles 301 in the polymer liquid crystal layer 30 are random and present a disordered state, the effective refractive index of the liquid crystal particles 301 is not matched with the refractive index of the polymer, so that the incident light is strongly scattered, at this time, the polymer liquid crystal layer 30 is present a scattering state, the LED light incident from the side surface changes the propagation direction of the incident light in the polymer liquid crystal layer 30 due to the scattering effect of the polymer liquid crystal, so that the light exits from the light exit surface of the light guide plate 20, the light emitted from the light source 10 is guided out through the light guide plate 20, and the uniform backlight is provided for the display.
As shown in fig. 1(b), since the polymer liquid crystal layer 30 has a homogeneous structure, the light intensity component is weakened along with the increase of the transmission distance during the transmission process of the light emitted from the LED, resulting in the occurrence of uneven light emission on the light emitting surface. Specifically, as shown in fig. 1(b), when light enters the light guide plate 20, the angle of the incident light entering the light exit surface of the light guide plate 20 is gradually reduced through multiple reflections inside the light guide plate 20, and therefore, the intensity of the light exiting from the side close to the LED light source 10 is greater than the intensity of the light exiting from the side far from the LED light source 10, which causes the light guide plate 20 to emit light unevenly.
Fig. 2 is a schematic structural view of a backlight module according to the present invention, the backlight module includes a light guide plate 20 and a light source 10 disposed at one side of the light guide plate 20, the light guide plate 20 includes a first transparent substrate 201 and a second transparent substrate 202 disposed opposite to each other, and a polymer liquid crystal layer 30 disposed between the first transparent substrate 201 and the second transparent substrate 202; wherein, the thickness of the polymer liquid crystal layer 30 gradually increases from the side close to the light source 10 to the side far away from the light source 10. Specifically, the light guide plate 20 has at least one side light incident surface, a first surface and a second surface opposite to the first surface, wherein the second surface is a light emitting surface; the light source 10 is disposed adjacent to the light incident side surface of the light guide plate 20, and the light emitted from the light source 10 is guided out through the light guide plate 20 to provide uniform backlight for the display panel. The first transparent substrate 201 is disposed close to the first surface, the second transparent substrate 202 is disposed close to the second surface, the thickness of the polymer liquid crystal layer 30 gradually increases from a side close to the light source 10 to a side far from the light source 10, and since the liquid crystal particles 301 are uniformly distributed in the polymer liquid crystal layer 30, the larger the thickness (cell gap) of the polymer liquid crystal layer 30 is, the more the number of the liquid crystal particles 301 formed after polymerization is, the higher the probability of being scattered in the light transmission process is, and thus the scattering degree is enhanced.
Optionally, the liquid crystal in the polymer liquid crystal layer 30 is a polymer dispersed liquid crystal or a polymer network liquid crystal.
In this embodiment, the cell gap of the polymer liquid crystal layer 30 is designed in a gradient manner, so that the cell gap of the polymer liquid crystal layer is larger at a position far away from the light source 10 than at a position near the light source 10, and therefore the polymer liquid crystal layer 30 is in a wedge shape in a direction from the light source 10 to the position far away from the light source 10, as shown in fig. 2, the polymer liquid crystal layer 30 is disposed between the first transparent substrate 201 and the second transparent substrate 202, so that the light guide plate 20 is also in a wedge shape in a direction from the light source 10 to the position far away from the light source 10. Since the degree of scattering of the polymer liquid crystal layer 30 is in direct proportion to the cell gap, that is, the larger the cell gap is, the larger the scattering degree of the polymer liquid crystal layer 30 is, the stronger the scattering effect on light is, the light emitting efficiency is correspondingly increased, the light guide plate 20 with the wedge-shaped structure has a gradient scattering degree in a scattering state, that is, as the cell gap of the polymer liquid crystal layer 30 increases away from the light source 10 to increase the degree of scattering of light therefrom, as shown in fig. 2, the problem that when the backlight module conducts light by using polymer liquid crystal, the light emitted by the light source 10 is reduced along with the increase of the transmission distance in the transmission process is solved, therefore, by adjusting and designing the thickness variation of the polymer liquid crystal layer 30 in the direction from the light source 10 to the direction away from the light source 10, the light emitting uniformity of the light guide plate 20 can be realized.
Optionally, the material of the first transparent substrate 201 and the second transparent substrate 202 is Polycarbonate (PC), polymethyl methacrylate (PMMA), or Methyl methacrylate-styrene copolymer (MS).
In a specific embodiment, the light guide plate 20 includes a first transparent electrode 211 and a second transparent electrode 212 disposed between the first transparent substrate 201 and the second transparent substrate 202, and the polymer liquid crystal layer 30 is disposed between the first transparent electrode 211 and the second transparent electrode 212, and the polymer liquid crystal layer 30 is controlled to switch between a transparent state and a scattering state by forming an electric field between the first transparent electrode 211 and the second transparent electrode 212.
Specifically, as shown in fig. 3, the second transparent substrate 202 is disposed opposite to the first transparent substrate 201; the first transparent electrode 211 is positioned on one side of the first transparent substrate 201 facing the second transparent substrate 202; the second transparent electrode 212 is located on the side of the second transparent substrate 202 facing the first transparent substrate 201, the polymer liquid crystal layer 30 is located between the first transparent electrode 211 and the second transparent electrode 212, and an electric field acting on the polymer liquid crystal layer 30 can be formed between the first transparent electrode 211 and the second transparent electrode 212.
Optionally, the material of the first transparent electrode 211 and the second transparent electrode 212 is nano silver, graphene, ITO (indium tin oxide), a nano material composite film, or a two-dimensional material film.
Specifically, in the present embodiment, when no electric field is formed between the first transparent electrode 211 and the second transparent electrode 212, the optical axis orientations of the liquid crystal particles 301 in the polymer liquid crystal layer 30 are random, and the polymer liquid crystal layer 30 is in a scattering state; when an electric field is formed between the first transparent electrode 211 and the second transparent electrode 212, liquid crystals in the polymer liquid crystal layer 30 are oriented perpendicular to the liquid crystal display panel along the direction of the electric field, the effective refractive index of the liquid crystal particles 301 is substantially matched with the refractive index of the polymer, and the polymer liquid crystal layer 30 is in a transparent state, and the polymer liquid crystal layer 30 can be controlled to be switched between the transparent state and the scattering state by changing the electric field between the first transparent electrode 211 and the second transparent electrode 212.
In a specific embodiment, the backlight module provided by the present invention includes a driving circuit, wherein the driving circuit may be formed on a flexible circuit board. Further, the driving circuit is respectively connected to the first transparent electrode 211 and the second transparent electrode 212, so as to control the polymer liquid crystal layer 30 to switch between a transparent state and a scattering state. When the polymer liquid crystal layer 30 is in a scattering state, the driving circuit controls the voltage between the first transparent electrode 211 and the second transparent electrode 212 to be zero or a smaller voltage, the liquid crystal particles 301 are not deflected, the polymer liquid crystal layer 30 is converted into the scattering state, and light incident from the side of the light guide plate 20 can be emitted from the light emitting side of the backlight module under the scattering effect of the polymer liquid crystal layer 30; when the polymer liquid crystal layer 30 is switched to the transparent state, a large voltage is applied between the first transparent electrode 211 and the second transparent electrode 212 through the driving circuit, at this time, the liquid crystal particles 301 are deflected, and the polymer liquid crystal layer 30 is switched to the transparent state, so that the light guide plate 20 does not deflect the laterally incident light to display the dark state.
It can be understood that the above-mentioned control method of applying a voltage to the first transparent electrode 211 and the second transparent electrode 212 to make the polymer liquid crystal layer 30 in the transparent state and making no electric field between the first transparent electrode 211 and the second transparent electrode 212 to control the polymer liquid crystal layer 30 in the scattering state is only an example, and other control methods may be used, for example, the first transparent electrode 211 and the second transparent electrode 212 make the polymer liquid crystal layer 30 in a transparent state under a voltage difference, the first transparent electrode 211 and the second transparent electrode 212 make the polymer liquid crystal layer 30 in a scattering state under another voltage difference, as long as the polymer liquid crystal layer 30 is controlled to switch between the transparent state and the scattering state by the electric field between the first transparent electrode 211 and the second transparent electrode 212.
Because the common substrate is made of PC or PMMA, the transparent electrode is easily deformed by patterning, and the transparent electrode can be deposited on a glass layer, and then bonded with the transparent substrate by using Optical Clear Adhesive (OCA) bonding or the like.
In a specific embodiment, in the backlight module provided by the present invention, the light guide plate 20 includes a plurality of supporting pillars 40 located between the first transparent substrate 201 and the second transparent substrate 202 and used for supporting the first transparent substrate 201 and the second transparent substrate 202, and the heights of the supporting pillars 40 are gradually increased from a side close to the light source 10 to a side far from the light source 10. Specifically, as shown in fig. 3, the supporting columns 40 are used to form a receiving space between the first transparent electrode 211 and the second transparent electrode 212, the polymer liquid crystal layer 30 is filled between the supporting columns 40, and the variation of the thickness of the polymer liquid crystal layer 30 can be realized by the variation of the heights of the supporting columns 40, in fig. 3, the height of the supporting column 40 from the side close to the light source 10 is smaller than the height of the supporting column 40 from the side far from the light source 10, so that the thickness of the polymer liquid crystal layer 30 gradually increases from the side close to the light source 10 to the side far from the light source 10.
Alternatively, the cross-sectional shape of the supporting column 40 may be a circle, an ellipse, a cross, a regular polygon, a flower shape, or a diamond shape.
It should be noted that the supporting columns 40 shown in fig. 3 are only examples, and a person skilled in the art may set the number and the position distribution of the specific supporting columns 40 according to actual requirements, in addition, the supporting columns 40 shown in fig. 3 are only an optional implementation manner for supporting the first transparent substrate 201 and the second transparent substrate 202, and a person skilled in the art may also support the first transparent substrate 201 and the second transparent substrate 202 by other manners, such as frame glue and the like.
In a specific embodiment, in the backlight module provided by the present invention, the first transparent substrate 201 is disposed obliquely with respect to the second transparent substrate 202. Specifically, as shown in fig. 3, the first transparent electrode 211 is horizontally disposed next to the first transparent substrate 201, the second transparent electrode 212 is horizontally disposed next to the second transparent substrate 202, which is inclined with respect to the first transparent electrode 211, and a vertical distance between the first transparent electrode 211 and the second transparent electrode 212 is equal to a height of the supporting pillar 40, such that a thickness of the polymer liquid crystal layer 30 gradually increases from a side close to the light source 10 to a side far away from the light source 10, and a light intensity of the polymer liquid crystal layer is improved by increasing a number of the polymer liquid crystals far away from the light source 10, thereby realizing a uniformity of light emitted from the light guide plate 20.
Optionally, the second transparent electrode 212 is horizontally disposed next to the second transparent substrate 202, the first transparent electrode 211 is obliquely disposed next to the first transparent substrate 201 relative to the second transparent electrode 212, and a vertical distance between the first transparent electrode 211 and the second transparent electrode 212 is equal to a height of the supporting pillar 40, so that a thickness of the polymer liquid crystal layer 30 gradually increases from a side close to the light source 10 to a side far from the light source 10. Moreover, since the second transparent electrode 212 and the second transparent substrate 202 close to the light-emitting surface are both horizontally disposed, the light-emitting surface can be kept horizontal in this embodiment, and the uniformity of the light emitted from the light guide plate 20 can be better controlled.
Alternatively, as shown in fig. 4, the second transparent electrode 212 is disposed adjacent to the second transparent substrate 202 and inclined with respect to the first transparent electrode 211, the first transparent electrode 211 is disposed adjacent to the first transparent substrate 201 and inclined with respect to the second transparent electrode 212, and a vertical distance between the first transparent electrode 211 and the second transparent electrode 212 is equal to a height of the supporting pillar 40, so that a thickness of the polymer liquid crystal layer 30 gradually increases from a side close to the light source 10 to a side far from the light source 10. Moreover, since the first transparent substrate 201 and the second transparent substrate 202 are both disposed in an inclined manner, the gradient of the thickness variation of the polymer liquid crystal layer 30 is increased, that is, compared with the case where only the second transparent substrate 202 is disposed in an inclined manner in fig. 3, in this embodiment, the thickness variation of the polymer liquid crystal layer 30 from the side close to the light source 10 to the side far from the light source 10 is more obvious, the number of polymer liquid crystals at the position far from the light source 10 is further increased, the light emitting intensity at the position far from the light source 10 is improved, and the light emitting uniformity of the light guide plate 20 is realized.
In a specific embodiment of the backlight module provided by the present invention, the first transparent substrate 201 is disposed in parallel with respect to the second transparent substrate 202, the light guide plate 20 includes a transparent film layer 50 disposed on a side of the second transparent substrate 202 facing the first transparent substrate 201, and the supporting pillars 40 are disposed between the first transparent substrate 201 and the transparent film layer 50. Specifically, as shown in fig. 5, the second transparent electrode 212 is horizontally disposed next to the second transparent substrate 202, the first transparent electrode 211 is horizontally disposed next to the first transparent substrate 201, the light guide plate 20 further includes a transparent film layer 50 disposed on the first transparent electrode 211 and facing the second transparent electrode 212, the supporting pillar 40 is disposed between the second transparent electrode 212 and the transparent film layer 50, so that the height of the supporting pillar 40 plus the thickness of the transparent film layer 50 is equal to the vertical distance between the first transparent electrode 211 and the second transparent electrode 212, wherein the height of the supporting pillar 40 gradually increases from the side close to the light source 10 to the side far from the light source 10, and the thickness of the transparent film layer 50 gradually decreases from the side close to the light source 10 to the side far from the light source 10, by controlling the height of the supporting pillars 40 and the thickness of the transparent film layer 50, the first transparent electrode 211 and the second transparent electrode 212 are parallel to each other, i.e., the vertical distance therebetween is equal, and the first transparent substrate 201 and the second transparent substrate 202 are also parallel to each other.
Alternatively, the side of the transparent film 50 close to the second transparent electrode 212 may be a curved surface, or may be an inclined plane, as long as the thickness of the transparent film 50 gradually decreases from the side close to the light source 10 to the side far from the light source 10.
Optionally, as shown in fig. 6, the second transparent electrode 212 is disposed adjacent to the second transparent substrate 202 horizontally, the transparent film layer 50 is disposed between the first transparent electrode 211 and the first transparent substrate 201, the first transparent electrode 211 is disposed adjacent to the first transparent substrate 201 horizontally, the light guide plate 20 further includes a transparent film layer 50 disposed on the first transparent electrode 211 and facing the second transparent electrode 212, the supporting pillar 40 is disposed between the first transparent electrode 211 and the second transparent electrode 212, so that the height of the supporting pillar 40 is equal to the vertical distance between the first transparent electrode 211 and the second transparent electrode 212, wherein the height of the supporting pillar 40 gradually increases from a side close to the light source 10 to a side far away from the light source 10, and the thickness of the transparent film layer 50 gradually decreases from a side close to the light source 10 to a side far away from the light source 10, by controlling the height of the supporting pillars 40 and the thickness of the transparent film layer 50, the first transparent substrate 201 and the second transparent substrate 202 are parallel to each other, i.e., the vertical distance therebetween is equal. Compared with the embodiment in fig. 5 in which the transparent film 50 is located between the first transparent electrode 211 and the second transparent electrode 212, in this embodiment, no transparent film 50 is disposed between the first transparent electrode 211 and the second transparent electrode 212, so as to avoid that the transparent film 50 may affect the control of the electric field between the first transparent electrode 211 and the second transparent electrode 212 on the polymer liquid crystal layer 30.
Optionally, the material of the transparent film layer 50 is an optically transparent adhesive.
In a specific embodiment, the backlight module further includes a reflective sheet 60 located on a side of the light guide plate 20 away from the light exit surface. Specifically, as shown in fig. 6, the reflective sheet 60 is disposed on a side of the first transparent substrate 201 away from the light exit surface, and the reflective sheet 60 controls reflection and refraction of light, so that a light path is controllable, and light that is not scattered in the light guide plate 20 is reflected and enters the light guide plate, thereby improving utilization rate of the light.
Optionally, the reflective sheet 60 surrounds the remaining surface of the light guide plate 20 except for the light incident side surface and the light exit side surface, so as to further enhance the reflection and refraction of light, thereby improving the utilization rate of light.
The material of the reflective sheet 60 is not limited, and the material of the reflective sheet 60 should be a material with high reflectivity, such as Ag (silver), Cu (copper), or a polycarbonate resin composition.
In addition, in order to further improve the display effect, the backlight module may further include a prism sheet (not shown) located on one side of the light exit surface of the light guide plate 20, and the prism sheet is used to concentrate the dispersed light to be emitted within a certain range, so as to improve the brightness of the light within the range;
optionally, the backlight module further includes a diffusion sheet (not shown) disposed on a side of the prism sheet facing away from the light exit surface of the light guide plate 20, and the uniformity of light emitted from the backlight module can be improved by the diffusion sheet; the material and structure of the diffusion sheet are not limited, as long as the light passes through the diffusion sheet and forms a uniform surface light source. The base material of the diffusion sheet may be, for example, PET (polyethylene terephthalate)/PC/PMMA, which have a high light transmittance. In addition, some scattering particles can be added into the base material of the diffusion sheet, and light can continuously pass through media with different refractive indexes when passing through the diffusion sheet, and simultaneously, a plurality of refraction, reflection and scattering phenomena can occur, so that the light can be diffused, and the effect of widening the visual angle can be achieved. The diffusion sheet may be an upper diffusion sheet or a lower diffusion sheet. When the diffusion sheet is an upper diffusion sheet, the diffusion sheet should have high light transmittance; when the diffusion sheet is a lower diffusion sheet, it should have a higher degree of scattering.
The embodiment of the invention also provides a display device, which comprises the backlight module and the display panel, wherein the display panel is arranged on one side close to the light-emitting surface of the light guide plate.
In summary, the present invention provides a backlight module and a display device, including a light guide plate and a light source disposed at one side of the light guide plate, wherein the light guide plate includes a first transparent substrate and a second transparent substrate disposed opposite to each other, and a polymer liquid crystal layer disposed between the first transparent substrate and the second transparent substrate, the thickness of the polymer liquid crystal layer is gradually increased from a side close to the light source to a side far from the light source, and the light intensity of the light guide plate is improved by increasing the amount of the polymer liquid crystal at the position far from the light source, so as to achieve uniformity of the light emitted from the light.
In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.
Claims (10)
1. The backlight module is characterized by comprising a light guide plate and a light source arranged on one side of the light guide plate, wherein the light guide plate comprises a first transparent substrate and a second transparent substrate which are oppositely arranged, and a polymer liquid crystal layer positioned between the first transparent substrate and the second transparent substrate;
wherein the thickness of the polymer liquid crystal layer gradually increases from the side close to the light source to the side far away from the light source.
2. The backlight module according to claim 1, wherein the light guide plate comprises a first transparent electrode and a second transparent electrode disposed opposite to each other between the first transparent substrate and the second transparent substrate, and the polymer liquid crystal layer is disposed between the first transparent electrode and the second transparent electrode.
3. The backlight module according to claim 2, wherein the light guide plate comprises a plurality of support pillars between the first transparent substrate and the second transparent substrate for supporting the first transparent substrate and the second transparent substrate, and the height of the support pillars increases from a side close to the light source to a side far from the light source.
4. The backlight module as claimed in claim 3, wherein the first transparent substrate is disposed obliquely with respect to the second transparent substrate.
5. The backlight module according to claim 3, wherein the first transparent substrate is disposed in parallel with respect to the second transparent substrate, the light guide plate comprises a transparent film layer disposed on a side of the second transparent substrate facing the first transparent substrate, and the support posts are disposed between the first transparent substrate and the transparent film layer.
6. The backlight module as claimed in claim 5, wherein the thickness of the transparent film layer is gradually decreased from a side close to the light source to a side far from the light source.
7. The backlight module as claimed in claim 6, wherein the material of the transparent film layer comprises an optically transparent adhesive.
8. The backlight module as claimed in claim 1, wherein the liquid crystal in the polymer liquid crystal layer is polymer dispersed liquid crystal or polymer network liquid crystal.
9. The backlight module as claimed in claim 1, wherein the backlight module further comprises a reflective sheet located on a side of the light guide plate away from the light-emitting surface.
10. A display device comprising a backlight module and a display panel, wherein the backlight module is the backlight module according to any one of claims 1 to 9.
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| CN202110283685.5A CN113075816A (en) | 2021-03-17 | 2021-03-17 | Backlight module and display device |
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| CN202110283685.5A CN113075816A (en) | 2021-03-17 | 2021-03-17 | Backlight module and display device |
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Application publication date: 20210706 |