CN114077094B - Light diffusion plate and method for manufacturing same - Google Patents
Light diffusion plate and method for manufacturing same Download PDFInfo
- Publication number
- CN114077094B CN114077094B CN202010812282.0A CN202010812282A CN114077094B CN 114077094 B CN114077094 B CN 114077094B CN 202010812282 A CN202010812282 A CN 202010812282A CN 114077094 B CN114077094 B CN 114077094B
- Authority
- CN
- China
- Prior art keywords
- light
- plastic substrate
- diffusion plate
- foaming
- light diffusion
- Prior art date
- Legal status (The legal status 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 status listed.)
- Active
Links
- 238000009792 diffusion process Methods 0.000 title claims abstract description 101
- 238000000034 method Methods 0.000 title claims abstract description 61
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- 238000001125 extrusion Methods 0.000 claims abstract description 60
- 238000005187 foaming Methods 0.000 claims abstract description 46
- 230000008569 process Effects 0.000 claims abstract description 46
- 239000013585 weight reducing agent Substances 0.000 claims abstract description 21
- 230000000694 effects Effects 0.000 claims abstract description 16
- 239000000975 dye Substances 0.000 claims description 92
- 229920003023 plastic Polymers 0.000 claims description 90
- 239000004033 plastic Substances 0.000 claims description 90
- 239000000758 substrate Substances 0.000 claims description 90
- 239000000463 material Substances 0.000 claims description 54
- 239000010410 layer Substances 0.000 claims description 34
- 238000006243 chemical reaction Methods 0.000 claims description 27
- 125000002080 perylenyl group Chemical group C1(=CC=C2C=CC=C3C4=CC=CC5=CC=CC(C1=C23)=C45)* 0.000 claims description 24
- CSHWQDPOILHKBI-UHFFFAOYSA-N peryrene Natural products C1=CC(C2=CC=CC=3C2=C2C=CC=3)=C3C2=CC=CC3=C1 CSHWQDPOILHKBI-UHFFFAOYSA-N 0.000 claims description 24
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 23
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 23
- 239000000843 powder Substances 0.000 claims description 22
- 239000002667 nucleating agent Substances 0.000 claims description 20
- ZYGHJZDHTFUPRJ-UHFFFAOYSA-N coumarin Chemical compound C1=CC=C2OC(=O)C=CC2=C1 ZYGHJZDHTFUPRJ-UHFFFAOYSA-N 0.000 claims description 16
- 239000004088 foaming agent Substances 0.000 claims description 16
- 239000004417 polycarbonate Substances 0.000 claims description 15
- 229920000515 polycarbonate Polymers 0.000 claims description 15
- 238000012545 processing Methods 0.000 claims description 14
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- -1 nitroso, carbonyl Chemical group 0.000 claims description 11
- 238000002156 mixing Methods 0.000 claims description 10
- 229960000956 coumarin Drugs 0.000 claims description 8
- 235000001671 coumarin Nutrition 0.000 claims description 8
- PYWVYCXTNDRMGF-UHFFFAOYSA-N rhodamine B Chemical compound [Cl-].C=12C=CC(=[N+](CC)CC)C=C2OC2=CC(N(CC)CC)=CC=C2C=1C1=CC=CC=C1C(O)=O PYWVYCXTNDRMGF-UHFFFAOYSA-N 0.000 claims description 8
- 229940043267 rhodamine b Drugs 0.000 claims description 8
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 239000002356 single layer Substances 0.000 claims description 6
- BCMCBBGGLRIHSE-UHFFFAOYSA-N 1,3-benzoxazole Chemical compound C1=CC=C2OC=NC2=C1 BCMCBBGGLRIHSE-UHFFFAOYSA-N 0.000 claims description 4
- GMQVFHZSXKJCIV-UHFFFAOYSA-N 2,2,2-trifluoro-n-(2,2,2-trifluoroacetyl)acetamide Chemical compound FC(F)(F)C(=O)NC(=O)C(F)(F)F GMQVFHZSXKJCIV-UHFFFAOYSA-N 0.000 claims description 4
- 241000224489 Amoeba Species 0.000 claims description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 4
- 125000000751 azo group Chemical group [*]N=N[*] 0.000 claims description 4
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 4
- 239000000292 calcium oxide Substances 0.000 claims description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 239000002131 composite material Substances 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 125000000524 functional group Chemical group 0.000 claims description 4
- 230000005484 gravity Effects 0.000 claims description 4
- 230000001788 irregular Effects 0.000 claims description 4
- 239000011859 microparticle Substances 0.000 claims description 4
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 4
- 239000002270 dispersing agent Substances 0.000 claims description 3
- 239000002861 polymer material Substances 0.000 claims description 3
- 239000004698 Polyethylene Substances 0.000 claims description 2
- 239000004743 Polypropylene Substances 0.000 claims description 2
- 239000004793 Polystyrene Substances 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims description 2
- 229920000573 polyethylene Polymers 0.000 claims description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 2
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 2
- 229920001155 polypropylene Polymers 0.000 claims description 2
- 229920002223 polystyrene Polymers 0.000 claims description 2
- 229920002050 silicone resin Polymers 0.000 claims description 2
- 150000003536 tetrazoles Chemical class 0.000 claims description 2
- 239000004408 titanium dioxide Substances 0.000 claims description 2
- 210000000497 foam cell Anatomy 0.000 claims 1
- 230000000052 comparative effect Effects 0.000 description 25
- 238000002834 transmittance Methods 0.000 description 12
- 239000004973 liquid crystal related substance Substances 0.000 description 9
- 238000012360 testing method Methods 0.000 description 8
- 238000003825 pressing Methods 0.000 description 7
- 239000002096 quantum dot Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 3
- 239000004156 Azodicarbonamide Substances 0.000 description 2
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 description 2
- 235000019399 azodicarbonamide Nutrition 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 238000009877 rendering Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
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
- G02F1/133606—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
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
- G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
- G02B5/0226—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures having particles on the surface
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
- G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
- G02B5/0247—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of voids or pores
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0268—Diffusing elements; Afocal elements characterized by the fabrication or manufacturing method
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0273—Diffusing elements; Afocal elements characterized by the use
- G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0273—Diffusing elements; Afocal elements characterized by the use
- G02B5/0294—Diffusing elements; Afocal elements characterized by the use adapted to provide an additional optical effect, e.g. anti-reflection or filter
-
- 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
- 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
- G02F1/133609—Direct backlight including means for improving the color mixing, e.g. white
-
- 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
- G02F1/133611—Direct backlight including means for improving the brightness uniformity
Abstract
A light diffusion plate and a manufacturing method thereof can be combined with a blue light source module comprising a plurality of blue light sub-millimeter light emitting diodes (Mini LEDs) to form a white light backlight module. At least one organic dye with the luminous wavelength of 490-650nm is added into the light diffusion plate, so that blue light emitted by the sub-millimeter light-emitting diode can be converted into white light to be emitted from a light emitting surface of the light diffusion plate. The light diffusion plate is manufactured by a foaming extrusion process, so that the light diffusion plate contains a plurality of microbubbles with the size of 60-400 mu m and the weight reduction percentage of 15-25%, light rays in the light diffusion plate are reflected, refracted or scattered, the uniformity of white light emitted from the light emitting surface is improved, and the problem of bright and dark blocks (MURA) caused by a light source of a backlight module is improved. In addition, in the foaming extrusion process, the size of the micro-bubbles is controlled to split by reducing the temperature of the front section at the outlet end of the T-shaped die, so that the wavelength of the white light emitted from the light emitting surface is narrower, and the effect of wider color gamut display is achieved.
Description
Technical Field
The present invention relates to a light diffusion plate and a method for manufacturing the same, and more particularly, to a light diffusion plate capable of combining a blue light source module including a plurality of blue sub-millimeter light emitting diodes (Mini LEDs) to form a white light backlight module and a method for manufacturing the same.
Background
Mini LED is a short for "sub-millimeter light emitting diode (Mini laser emitting diode)", meaning an LED with a die size of about 100-200 micrometers (μm). Because the grain size of Micro LEDs (Micro light emitting diodes) is below 50 microns, technical barriers such as high manufacturing cost and mass transfer still exist, so that a Mini LED with relatively mature manufacturing technology is developed as a whistle station for the development of Micro LEDs.
The Mini LED has the size and technology between that of the traditional LED and that of the Micro LED, has high yield in the manufacturing process compared with that of the Micro LED, has special-shaped cutting characteristic, and can also achieve the form of a high-curved-surface backlight module by matching with a flexible substrate. The Mini LED backlight module can adopt a local dimming design, has better color rendering, can bring finer High-Dynamic Range (HDR) partition to a liquid crystal display Panel (Liquid Crystal Display Panel; abbreviated as LCD Panel), and has a thickness similar to that of an Organic Light-Emitting Diode (OLED), and can save electricity by 80%, so that the application of backlight sources such as electricity saving, thinning, HDR, abnormal-shaped display and the like is a complaint. In the liquid crystal display using the backlight module as the light source, the Mini LED has high brightness and high contrast and high display effect, and the cost of the Mini LED backlight module is cheaper than that of the backlight module formed by RGB three primary color Mini LEDs after the Mini LED backlight module is changed to a blue light Mini LED chip as a basic light source, and the Mini LED backlight module is more suitable for being applied to the backlight modules of products such as mobile phones, tablet computers, desktop displays, televisions, vehicle panels, electronic contest notebook computers and the like.
The traditional white light LED backlight module is manufactured by encapsulating fluorescent powder directly on the upper surface of an LED chip in a dispensing mode. The fluorescent powder can generate precipitation after being mixed with glue, so that the color temperature is unevenly dispersed and cannot be concentrated; in addition, the fluorescent powder directly contacts the surface of the chip, so that the problems of overlarge heating value, poor heat dissipation of the fluorescent powder, reduced efficiency and the like are easy to occur. Another prior art is to add a quantum dot film on a light diffusion plate of a backlight module to match with a blue LED module to generate white light. The basic principle is that the blue light LED chip is combined with green light and red light quantum dots in the film to be converted into white light. The prior art has the advantages that the color gamut display is wide, the color control is more accurate, and the quantum dots are inorganic materials with good stability; however, the disadvantages are that the quantum dot film is expensive, cadmium element is toxic in the preparation process, and water and soil environment pollution can be caused if the quantum dot film is improperly treated. Therefore, the prior art of applying Mini LEDs to white light backlight modules still has drawbacks, and needs to be further improved.
Disclosure of Invention
The main purpose of the invention is to provide a light diffusion plate matched with blue light Mini LEDs, which is directly added with organic dye in the extrusion process of the light diffusion plate, and the organic dye is uniformly dispersed in plastic materials for converting blue light emitted by the blue light Mini LEDs into white light, so as to achieve the achievement of uniform dispersion and consistent color temperature and thickness. And the resin material of the light diffusion plate has high temperature resistance and good mechanical property, so that the service life of the light-emitting efficiency of the organic dye can be prolonged, and the resin material is not influenced by heat emitted by the chip. In addition, the light diffusion plate is combined by a foaming extrusion process, and a plurality of micro bubbles are mixed in the plastic material of the light diffusion plate, so that the light emission is more uniform; the size of the air hole of the micro bubble is controlled to carry out light splitting, the wavelength of the light can be narrowed, and the effect of wider color gamut display is achieved.
Another object of the present invention is to provide a method for manufacturing a light diffusion plate used with blue light Mini LEDs. The method comprises adding a nucleating agent in the foaming extrusion process of the light diffusion plate, uniformly mixing and foaming by an extrusion screw section, and reducing the temperature of the front section at about 20-30 ℃ at the outlet end of a T-die to cool and bundle the cells, thereby controlling the size of the microbubbles.
In order to achieve the above-mentioned object, the present invention discloses a light diffusion plate for being combined with a blue light source module and converting blue light into white light, comprising: a plastic substrate, at least one light color conversion material, and a plurality of micro bubbles. The plastic substrate has a light incident surface and a light emergent surface parallel to each other, and a thickness perpendicular to the light incident surface and the light emergent surface; the light incident surface is adjacent to the blue light source module, so that blue light emitted by the blue light source module can be incident into the plastic substrate through the light incident surface and can generally travel along the thickness direction. The at least one light color conversion material is dispersed in the plastic substrate, and can convert the blue light entering the plastic substrate into white light and then emit the white light from the light emitting surface. The micro bubbles are dispersed in the plastic substrate, and can perform at least one of the following functions on the light rays in the plastic substrate: reflection, refraction or scattering can improve the effect of uniform light emission on the white light emitted from the light emitting surface.
In one embodiment, the blue light source module is a sub-millimeter light emitting diode (Mini LED) array module capable of emitting the blue light; the wavelength of the blue light is 430-500nm; the at least one light color conversion material comprises one of the following: organic dye, inorganic fluorescent powder; the micro-bubbles are formed in the plastic substrate by a foaming extrusion process of the light diffusion plate.
In one embodiment, the at least one light color conversion material comprises the organic dye having an emission wavelength of 490-650 nm; the molecule of the organic dye comprises at least one of the following functional groups: azo, nitro, nitroso, carbonyl; the organic dye may comprise at least one of: perylene (Perylene), coumarin (Coumarin), eu (BTFA) 3phen, benzoxazolium dye (dye), rhodamine B (Rhodamine B), pyrelmethene dye (dye), perylene (Perylene) orange, perylene (Perylene) red.
In one embodiment, the at least one light color conversion material includes two organic dyes, wherein one of the organic dyes has a light emission wavelength of 520-530nm and the other organic dye has a light emission wavelength of 620-630nm.
In one embodiment, the organic dye is added in a proportion of 0.0001% to 5%; the weight reduction percentage of the micro bubbles to the plastic substrate is 10-35%, and the average size of each micro bubble is 60-800 mu m.
In one embodiment, the organic dye is added in a proportion of 0.01% -0.5%; the weight reduction rate of the micro bubbles to the plastic substrate is 15-25%, and the average size of each micro bubble is 60-400 mu m; the weight reduction rate has the following calculation formula:
weight reduction (%) = (W1-W2)/W2 x 100%;
W1＝H*(L1*L2*D)；
wherein: h is the average thickness (mm) of the plastic substrate; l1 is the length (mm) of the plastic substrate; l2 is the width (mm) of the plastic substrate; d is the specific gravity (g/mm 3) of the raw material of the plastic substrate; w1 is the theoretical weight (g) of the plastic substrate, i.e., the weight without the microbubbles; w2 is the actual weight (g) of the plastic substrate, i.e., the actual weight of the plastic substrate containing the plurality of microbubbles is actually weighed using a weigh scale.
In one embodiment, the size of the plurality of microbubbles is controlled by the temperature of an extrusion process of the diffuser plate; in the extrusion process of the light diffusion plate, after uniformly mixing and foaming by an extrusion screw section, reducing the temperature of the front section at the outlet end of a T-shaped die (T-die) so as to achieve the effect of cooling and converging the foam holes; wherein the temperature of the front section of the outlet end of the T-shaped DIE head (T-DIE) is reduced by 20-30 ℃.
In one embodiment, during the extrusion process, the light diffusion plate is added with a nucleating agent to assist in controlling the size of the plurality of microbubbles; the nucleating agent comprises at least one of the following: calcium carbonate, silica, and calcium oxide; the weight percentage of the nucleating agent added is 0.1% -0.5%.
In one embodiment, the thickness of the plastic substrate ranges from 0.1mm to 3.0mm; arranging a microstructure layer on the light-emitting surface of the plastic substrate; the surface of the microstructure layer is provided with a plurality of microstructures consisting of convex parts or concave parts; the plurality of microstructures may be one of: round, irregular foggy, amoeba, pyramidal.
In one embodiment, the preferred thickness range of the plastic substrate is 0.2 mm-2.0 mm; the light incident surface is one of the following: a mirror or another microstructure layer without the microstructure; the microstructure layer of the light-emitting surface is provided with a plurality of pyramid microstructures.
In order to achieve the above-mentioned object, the present invention discloses a method for manufacturing a light diffusion plate, comprising the following steps: putting a base material of a plastic substrate and at least one light color conversion material forming the light diffusion plate into foaming extrusion processing equipment through a feed inlet; uniformly mixing and foaming at a common processing temperature suitable for polycarbonate in an extrusion screw section of the foaming extrusion process equipment; extruding the uniformly mixed and foamed base material from the extruding screw section into a plate through a T-shaped die of the foaming extrusion process equipment; after the plate is rolled and formed by a roller module of the foaming extrusion processing equipment and cooled, the cooled light diffusion plate is sent out from a discharge hole of the foaming extrusion processing equipment; the method is characterized in that: after the base material and the light color conversion material are uniformly mixed and foamed in the extrusion screw section, the temperature of the front section is reduced by 20-30 ℃ at an outlet end of the T-shaped die so as to cool and converge the size of a plurality of micro bubbles contained in the plastic substrate to be within the range of 60-400 mu m.
In one embodiment, in addition to the substrate and the at least one light color conversion material, a foaming agent, a nucleating agent and a dispersing agent are also fed into a foaming extrusion process device through the feed port for uniform mixing and foaming; the typical processing temperature for polycarbonate is between 220 and 270 ℃, and the temperature of the previous stage of the T-die is about 270 ℃, and the temperature of the previous stage at the exit end of the T-die is reduced to between 240 and 250 ℃.
Drawings
FIG. 1 is a schematic side view of a preferred embodiment of the light diffusion plate of the present invention combined with a blue light source module to form a white light backlight module and disposed under a liquid crystal display panel.
Fig. 2 is a schematic exploded perspective view of a preferred embodiment of the light diffusion plate of the present invention combined with a blue light source module to form a white light backlight module and disposed under a liquid crystal display panel.
Fig. 3 is a schematic view illustrating an embodiment of a method for manufacturing a light diffusion plate according to the present invention.
FIG. 4 is a MURA chart obtained by testing each of the light diffuser plate samples shown in Table V according to the present invention.
FIG. 5 is a spectrum of the wavelengths of light intensity vs obtained according to the light diffusion plate samples shown in Table six and Table seven (example 2 and example 5) of the present invention.
List of reference numerals: 10-a light diffusion plate; 11-a plastic substrate; 111-a master layer; 112. 113-a secondary ply; 1121-a light exit surface; 1122-microstructure; 1131—a light incident surface; 12-a light color conversion material; 13-microbubbles; a 20-blue light source module; 21-a circuit board; 22; -a blue sub-millimeter light emitting diode; 30-a liquid crystal display panel; 50-foaming extrusion process equipment; 51-a feed inlet; 52-extruding the screw section; a 53-T die; 531-outlet end; 54-roller module.
Detailed Description
The invention relates to a light diffusion plate and a manufacturing method thereof. The light diffusion plate can be combined with a blue light source module comprising a plurality of blue sub-millimeter light emitting diodes (Mini LEDs) to form a white light backlight module. At least one organic dye with the luminous wavelength of 490-650nm is added into the light diffusion plate, so that blue light emitted by the sub-millimeter light-emitting diode can be converted into white light to be emitted from a light emitting surface of the light diffusion plate. The light diffusion plate is manufactured by a foaming extrusion process, so that a plurality of micro bubbles with the size of 60-800 mu m and the weight reduction percentage of 10-35% can be contained in the light diffusion plate, light in the light diffusion plate can be reflected, refracted or scattered, the uniformity of white light emitted from the light emitting surface can be improved, and the problem of light and dark blocks (MURA) caused by a light source of a backlight module can be improved. And by controlling the sizes of the micro bubbles to carry out light splitting, the wavelength of the white light emitted from the light emitting surface is narrower, and the effect of wider color gamut display is achieved. In the manufacturing method of the light diffusion plate, a nucleating agent is added in the foaming extrusion process of the light diffusion plate, and after the foaming is evenly performed by uniformly mixing and foaming by an extrusion screw section, the temperature of the front section is reduced by about 20-30 ℃ at the outlet end of a T-shaped die (T-die) so as to achieve the purpose of cooling and converging the cells, thereby controlling the sizes of the micro-bubbles.
In order to more clearly describe the polymer plastic front panel and the manufacturing method thereof according to the present invention, the following detailed description will be given with reference to the drawings.
Referring to fig. 1 and 2, a light diffusion Plate 10 (Diffuser Plate) of the present invention is combined with a blue light source Module 20 to form a white light Backlight Module (Backlight Module) and is a schematic view of a preferred embodiment disposed under a liquid crystal display Panel 30 (LCD Panel) in side view and in perspective view.
As shown in fig. 1 and 2, the light diffusion plate 10, the blue light source module 20 below the light diffusion plate 10, and the liquid crystal display panel 30 above the light diffusion plate 10 form an LCD display module. In an embodiment, the Light diffusion plate 10 of the present invention can be combined with the blue Light source module 20 located below to form a white Light backlight module for providing white Light to the liquid crystal display panel 30 located above, so it is a Direct Light (Direct Light) backlight module. The light diffusion plate 10 mainly provides the functions of converting blue light into white light, making the light output uniform, and enlarging the color gamut of the light output, and includes: a plastic substrate 11, at least one light-color conversion material 12, and a plurality of micro-bubbles 13.
In the present invention, the blue light source module 20 is a sub-millimeter light emitting diode (Mini LED) array module capable of emitting blue light, and includes a circuit board 21 and a plurality of blue sub-millimeter light emitting diodes 22 disposed on the upper surface of the circuit board in an array form. In this embodiment, the wavelength of blue light emitted from each sub-millimeter LED 22 is 430-500nm, and the grain size is about 100-200 μm.
The plastic substrate 11 has a light incident surface 1131 and a light emergent surface 1121 with relatively large length and width and parallel to each other, and a relatively small thickness perpendicular to the light incident surface 1131 and the light emergent surface 1121. The light incident surface 1131 is adjacent to the blue light source module 20, so that the blue light emitted from the blue light source module 20 can be incident into the plastic substrate 11 through the light incident surface 1131 and generally travels along the thickness direction, and is emitted upwards from the rear light emitting surface 1121 after being converted into white light. The substrate of the plastic substrate 11 of the present invention may be an amorphous or semi-crystalline plasticized material such as Polycarbonate (PC), polystyrene, polymethyl methacrylate (PMMA), polyethylene, polypropylene, polyethylene terephthalate, and the like. The plastic substrate 11 may have one of the following structures: polymethyl methacrylate (PMMA) single-layer plates, polycarbonate (PC) single-layer plates, PMMA/PC double-layer composite plates, PMMA/PC/PMMA three-layer composite plates, or other high polymer material single-layer or multi-layer co-extrusion plates, and the like. The thickness H of the plastic substrate 11 can be in the range of 0.1mm to 3.0mm, and the thickness is preferably in the range of 0.2mm to 2.0mm. In this embodiment, the plastic substrate 11 is preferably a multi-layer board (PMMA/PC/PMMA three-layer board), which may be Polycarbonate (PC) as the Main board layer 111 (Main-layer) material, and its thickness is 60% -99.99% of the total thickness of the plastic substrate 11. The thicknesses of the Sub-layers 112, 113 (Sub-layers) respectively located on the upper and lower sides of the main board layer 111 are 0.01% -40% of the total thickness of the plastic substrate 11, and the material thereof can be selected from any one of the following materials: PMMA, modified PMMA, and the like. A microstructure layer is disposed on the light-emitting surface 1121 of the plastic substrate 11 (i.e., the upper surface of the upper PMMA sub-layer 112) by extrusion molding. The surface of the microstructure layer has a plurality of microstructures 1122 composed of convex portions or concave portions, which may be regularly or irregularly distributed on the surface of the light diffusion plate 10 (the light-emitting surface 1121 of the plastic substrate 11); the plurality of microstructures 1122 may be one of the following: round, irregular foggy, amoeba, pyramidal. The light incident surface 1131 (i.e. the lower surface of the lower PMMA sub-layer 113) may be one of the following: smooth and without a mirror of microstructure, or with another microstructured layer. In the preferred embodiment of the present invention, the light incident surface 1131 (i.e. the lower surface of the lower PMMA sub-layer 113) is a mirror surface; the microstructure layer of the light-emitting surface 1121 has a plurality of pyramid microstructures 1122, and this design improves the overall luminance optimally.
The at least one light color conversion material 12 is mixed and uniformly dispersed in the material of the main board layer 111 of the plastic substrate 11, and can convert the blue light entering the plastic substrate 11 into white light and then emit the white light from the light emitting surface 1121. The at least one light color conversion material may include one of: organic dyes, inorganic phosphors, or both. In the present invention, the molecule of the organic dye contains one or more of the following functional groups: azo, nitro, nitroso, carbonyl, and the like; and, the organic dye 12 may comprise at least one of: perylene (Perylene), coumarin (Coumarin), eu (BTFA) 3phen, benzoxazolium dye (dye), rhodamine B (Rhodamine B), pyrelmethene dye (dye), perylene (Perylene) orange, perylene (Perylene) red, and the like. In one embodiment, the at least one light color conversion material 12 comprises an organic dye having an emission wavelength of 490-650 nm. In a preferred embodiment of the present invention, the at least one light color conversion material 12 comprises two or more organic dyes having different emission wavelengths, wherein one of the organic dyes has an emission wavelength of 520-530nm and the other organic dye has an emission wavelength of 620-630nm. An exemplary ratio (weight percent) of the organic dye is 0.0001% -5%, and a preferred embodiment is 0.01% -0.5%, and the amount of the organic dye is adjusted according to the kind of the organic dye and the target thickness of the light diffusion plate 10. In another embodiment, the at least one light color conversion material 12 of the present invention may also be added with one or more inorganic fluorescent powders, or mixed with organic dye and inorganic fluorescent powder and uniformly dispersed in the plastic substrate 11. However, the organic dye is generally mixed relatively more uniformly into the plastic substrate material of the light diffusion plate 10 than the inorganic fluorescent powder, and the physical properties of the light diffusion plate 10 to which the two organic dyes are added and to which no inorganic fluorescent powder is added are relatively better than those of the light diffusion plate 10 to which at least one inorganic fluorescent powder is added.
The micro bubbles 13 are dispersed in the material of the main board layer 111 of the plastic substrate 11, and the micro bubbles 13 can perform at least one of the following functions on the light in the plastic substrate 11: reflection, refraction or scattering. The micro bubbles 13 with a proper proportion can improve the effect of uniform light emission of the white light emitted from the light emitting surface 1121, so as to improve the problem of bright and dark areas (MURA) caused by the light source of the backlight module. Further, by controlling the size of the microbubbles 13 to perform light splitting, the wavelength of the white light emitted from the light emitting surface 1121 can be made narrower, and a wider color gamut display can be achieved. In the present invention, an exemplary ratio (also referred to as a weight reduction percentage or a weight reduction (%)) of the micro bubbles 13 to the plastic substrate 11 is between 10 and 35%, and an average size of the micro bubbles 13 is between 60 and 800 μm. In a preferred embodiment, the weight reduction ratio of the micro-bubbles 13 to the plastic substrate 11 is 15-25%, and the average size of the micro-bubbles 13 is preferably 60-400 μm. The weight reduction rate has a calculation formula as follows:
microbubble ratio (%) = weight loss (%) = (W1-W2)/W2 x 100%;
W1＝H*(L1*L2*D)；
Wherein (refer to fig. 2):
h is the average thickness (mm) of the plastic substrate;
l1 is the length (mm) of the plastic substrate;
l2 is the width (mm) of the plastic substrate;
d is the specific gravity (g/mm) of the raw material of the plastic substrate 3 )；
W1 is the theoretical weight (g) of the plastic substrate, i.e., the weight without the microbubbles;
w2 is the actual weight (g) of the plastic substrate, i.e., the actual weight of the plastic substrate containing the plurality of microbubbles is actually weighed using a weigh scale.
In the present invention, the plurality of micro bubbles 13 are formed in the plastic substrate 11 by a foaming extrusion process of the light diffusion plate 10; the ratio of the micro-bubbles (weight reduction ratio) of the micro-bubbles 13 can be controlled by the amount of the foaming agent, and the size of the micro-bubbles 13 is controlled by the process temperature of the light diffusion plate 11 in the foaming extrusion process and the addition of the nucleating agent (Nucleating Agents). In the present invention, the foaming agent used is selected from the commercially available existing high temperature foaming agents such as (but not limited to): 5-basic tetrazole (5-PT), azo dicarbonamide (azo dicarbonamide), etc. The amount of the foaming agent of different types and brands is equal to the amount of the generated micro-bubbles in a proper foaming temperature range, so that the weight reduction ratio of the micro-bubbles 13 to the plastic substrate 11 can be adjusted to a required range by increasing and decreasing the amount of the foaming agent. The nucleating agent is a commercially available existing nucleating agent, and comprises the following components: calcium carbonate, silica, calcium oxide, etc., which act to promote the number of nuclei and reduce the average size of the nuclei, can be used to control the size of microbubbles. Wherein, the weight percentage of the nucleating agent added is 0.01% -5% of the embodiment, and the optimal proportion is 0.1% -0.5%.
Referring to FIG. 3, a method for manufacturing a light diffusion plate 10 according to an embodiment of the invention is shown. In the foaming extrusion process of the light diffusion plate 10, firstly, the base material of the plastic substrate forming the light diffusion plate 10 is put into the foaming extrusion process equipment 50 together with at least one light color conversion material, foaming agent, nucleating agent, diffusing agent and the like through the feeding port 51 (Hopper); then, the extruder screw 52 is uniformly foamed by kneading in sequence the sections A1 to A11 (including the feeding sections A1 to A3, the compression kneading sections A4 to A8, and the metering sections A9 to A11) at a general processing temperature (the processing temperature is adjusted depending on the type of the foaming agent, and is usually 220 to 270 ℃); then, the uniformly kneaded and foamed base material from the A11 section of the extrusion screw section 52 is extruded into a plate material of a predetermined thickness and width through a T-die 53 (T-die); after that, the sheet is roll-formed and cooled by the roller module 54, and the cooled light diffusion plate 10 is sent out from the discharge port 55. In the present invention, when the base material constituting the plastic substrate, the light color conversion material, the foaming agent and the nucleating agent are uniformly mixed and foamed in the extruder screw section 52 sequentially from the section A1 to the section a11, the light diffusion plate manufacturing method of the present invention reduces the front temperature at the outlet end 531 (also called lip) of the T-die 53 (T-die) to achieve the effect of cooling and converging the cells of the microbubbles contained in the plastic substrate. Wherein the temperature of the front stage of the outlet end of the T-die 53 (T-die) is 20-30 ℃ lower than the temperature of the process of the front stage of the extrusion screw section 52 (i.e. the A11 section). For example, if the processing temperature at the A11 stage is about 270 ℃, the temperature of the front stage of the outlet end of the T-die 53 (T-die) is reduced to 240-250 ℃, thereby converging the size of the microbubbles contained therein to a range of 60-400 μm. The invention controls the size of the micro-bubbles to enable the size of the micro-bubbles to be less than 400um, the center wavelength to move backwards by 4-5 nm, and the invention has the effect of narrowing the wavelength, thus the color gamut can be wider. When the average bubble diameter size of the micro bubbles is 400-600 um, the wavelength is not narrowed, but the center wavelength moves backwards by 2-3 nm; while there is no significant effect if the average bubble diameter size of the microbubbles is >600 um. In one embodiment, the diffusing agent comprises diffusing particles composed of at least one of the following materials: calcium carbonate, silica, titanium dioxide, silicone resin microparticles, polymethyl methacrylate microparticles; the weight percentage of the added diffusing agent is 0.1% -10%.
The applicant has added a single organic dye of different wavelengths to a plurality of different light diffusion plate samples (comparative examples 1 to 5 and example 1 shown in the following table one), the wavelengths of the organic dyes added to the plurality of different samples are selected from the range of 490 to 650nm and are different from each other, the samples shown in comparative examples 1 to 5 and example 1 shown in the following table one are observed, and then the light emission color of each light diffusion plate sample and the test results of measuring The Transmittance (TT) and illuminance value (lux) of the blue light Mini LED are shown in the following table one.
Table one: light-emitting performance of several light diffusion plate samples added with single organic dyes of different wavelengths
As can be seen from the above table, the two samples of comparative example 3 and example 1 have relatively good TT, lux and color appearance (light emission closer to white light) because the wavelength of the added single organic dye is between 520 and 540nm, but the color saturation of the two samples of comparative example 3 and example 1 is still not high enough due to the lack of red light wavelength, which is only marginal. For other samples (comparative examples 1,2,4, 5), the color of the emitted light is far from that of white light because the wavelength of the single organic dye added is either below 500nm or above 560nm, which is not useful.
The applicant also added two organic dyes of different wavelengths to a plurality of different samples of light diffusion plate (comparative examples 6 to 9 and example 2 shown in table two below), and the wavelengths of the two organic dyes added to the plurality of different samples were selected from the range of 490 to 650nm and were different from each other. The samples shown in comparative examples 6 to 9 and example 2 of Table II below, in which the wavelength of the first organic dye added was in the range of 490 to 530nm and the wavelength of the second organic dye was in the range of 600 to 650nm, were examined, and the light-emitting color of each light diffusion plate sample was observed along with the blue Mini LED, and the results of the measurement of The Transmittance (TT) and illuminance (lux) were shown in Table II below.
And (II) table: light-emitting behavior of several light-diffusing plate samples with addition of two organic dyes of different wavelengths
As can be seen from the above table two, in example 2, since the wavelength of the two organic dyes added is between 520 to 530nm (green wavelength) and 620 to 630nm (red wavelength), respectively, the color appearance of TT, lux and light emission (white light emission) is relatively optimal, and the color purity is high and the color gamut is wide. In contrast, the other samples (comparative examples 6,7,8, and 9) were inferior to the sample of example 2 in terms of the color of the emitted light and the white light, since at least one of the two organic dyes added was not between 520 and 530nm or between 620 and 630 nm.
Further, the applicant added one and two kinds of inorganic fluorescent powders to two different samples of light diffusion plate (comparative example 10 and example 3 shown in the following table three), respectively; the wavelength ranges of the comparative example 10 sample to which only a single organic dye was added were 520 to 530nm, and the wavelength ranges of the two organic dyes added in the example 3 sample were 520 to 530nm and 620 to 630nm, respectively, and then the light-emitting color of each light diffusion plate sample with blue Mini LED was observed, and the test results of measuring The Transmittance (TT) and illuminance (lux) thereof were shown in the following Table III.
Table three: light-emitting performance of several light diffusion plate samples added with single inorganic fluorescent powder and two inorganic fluorescent powders with different wavelengths
As can be seen from Table three above, example 3 thus has relatively optimal TT, lux and color appearance (white light) because the wavelengths of the two inorganic fluorescent powders added are between 520-530 nm and 620-630 nm, respectively. In the sample of comparative example 10, the wavelength of the fluorescent powder was 520-530 nm, so that the color of the emitted light was still different from that of the white light, and the emitted light was not as good as that of the sample of example 3.
Applicants added inorganic fluorescent powders and organic dyes of different wavelengths to a light diffuser plate sample (example 4 shown in table four below); the wavelength range of the inorganic fluorescent powder added in the sample of example 4 is 520-530 nm, the wavelength range of the organic dye is 620-630 nm, and then the test results of observing the light color of the blue light Mini LED and measuring The Transmittance (TT) and illuminance (lux) of the sample of example 4 are shown in the following table four.
Table four: light emitting performance of light diffusion plate sample added with inorganic fluorescent powder and organic dye with different wavelengths
As can be seen from Table four, in example 4, the wavelengths of the added inorganic fluorescent powder and organic dye are respectively between 520-530 nm and 620-630 nm, so that even if the inorganic fluorescent powder and organic dye are mixed, the TT, lux and the color appearance (white light) can be relatively optimized.
Further, the applicant added foaming agents in different proportions to several different samples of light diffusion plate (comparative examples 11 to 15 and examples 2 and 5 shown in the following table five) to make the ratio of micro bubbles contained in the plastic substrate (weight reduction ratio) different, and then observed the improvement degree and luminance difference of the different ratio of micro bubbles (weight reduction ratio) to the MURA of the light diffusion plate, and the test results thereof are shown in the following table five and fig. 4. The thickness of each light diffusion plate sample in Table five was between 1.479 and 1.495mm, and two organic dyes of different wavelengths were added as well, one of which was the organic dye of No. 2 (wavelength 525nm, full width half maximum FWHM value 31 nm) and the other was the organic dye of No. 6, the wavelength 626nm, full width half maximum FWHM value 41nm. FIG. 4 is a MURA chart obtained by testing each of the light diffuser plate samples shown in Table V according to the present invention. In the MURA diagram of each light diffusion plate sample shown in FIG. 4, bright spots are arranged above the LEDs, dark spots are arranged between the LEDs, and the contrast between the bright spots and the dark spots is obvious.
Table five: light-emitting behavior of several light diffuser plate samples with different ratios of foaming agent added
As can be seen from the above table five, when the amount of the foaming agent added is increased, the shielding effect of MURA is improved, but too much luminance is lost. As shown in table five together with fig. 4, when the weight reduction ratio of the foaming agent added to the light diffusion plate sample is in the range of 15-25%, a relatively good balance of MURA and luminance can be obtained.
In addition, in the foaming extrusion process of several different samples of light diffusion plate (comparative examples 16 to 18 and examples 2,5, and 6 shown in the following Table six), the applicant used different process temperatures to control the diameters of the microbubbles (abbreviated as bubble diameters) contained in each sample of light diffusion plate. That is, in the foaming extrusion process of each light diffusion plate sample, after the extrusion screw is used for uniformly mixing and foaming, the temperature of the front section is reduced by different temperature differences at the outlet end of the T-die so as to cool and converge the micro-bubble holes, and then the bubble diameter size range of the micro-bubbles formed in each light diffusion plate sample is measured, and the test results are shown in the following Table six. The thickness of each light diffusion plate sample in Table six was 1.488-1.505 mm, and two organic dyes of different wavelengths were added as well, one of which was the organic dye of No. 2 (wavelength 525nm, full width half maximum FWHM value 31 nm) and the other was the organic dye of No. 6, the wavelength 626nm, full width half maximum FWHM value 41nm. The extrusion temperature values of columns A1, A2, A3, A4, A5 to A11, T-die, etc. shown in Table six may correspond to the process temperature values at the positions of sections A1 to A11 and T-die 53, respectively, in the foam extrusion process apparatus 50 shown in FIG. 3.
Table six: test results for controlling the bubble diameter of microbubbles contained in each light diffusion plate sample by using different process temperatures in the foaming extrusion process
As can be seen from the above table six, in combination with the positions of the sections A1 to A11 and the T-die 53 in the foaming extrusion process equipment 50 shown in FIG. 3, in the foaming extrusion process of the light diffusion plate samples (comparative examples 16 to 18 and examples 2,5 and 6), the bubble diameter of the microbubbles contained in the light diffusion plate can be reduced to a range of 60 to 400 μm by reducing the temperature of the front section of the T-die outlet end (for example, 250℃in example 5 and 240 ℃) compared with the temperature of the section A11 (for example, 270℃in both of example 5 and example 6). If the temperature of the front section of the T-die outlet end is too high, the problem that the bubble diameter is too large easily occurs too early in gas generation exists, for example, the temperature of the T-die outlet end of comparative example 17 is 270 ℃, and the bubble diameter is 155-810 mu m. On the other hand, the bubble diameter can be effectively reduced by adding the nucleating agent, and as shown in comparative example 18, even if other process conditions (including the temperature of the T-die outlet end being 270 ℃) are the same as those of comparative example 17, the bubble diameter of comparative example 18 can be reduced to 120 to 685. Mu.m.
Continuing from the above table six, when different process temperatures are used to control the bubble diameter of the microbubbles contained in each light diffuser sample during the foaming extrusion process, the wavelength shift and FWHM values of each light diffuser sample before and after the extrusion will also be different, as shown in table seven below.
Table seven: a comparison table for comparing the wavelength shift amount of the organic dye and the difference of the full width at half maximum FWHM value of each light diffusion plate sample before and after the extrusion plate when using different process temperatures to control the bubble diameter of the micro bubble in each light diffusion plate sample in the foaming extrusion process
Referring to fig. 5, a spectrum of the light wavelengths vs of the light intensity obtained according to the light diffusion plate samples (example 2 and example 5) shown in the sixth and seventh tables of the present invention is shown. The color gamut is the number of colors that a color display can display, and is also referred to as color saturation in practice. Color gamut characteristics are important indicators of the ability of a display to exhibit its color with respect to the importance of the color rendering illumination source. Color gamut characteristics of color displays are often closely related to the dominant wavelength of red, green, and blue primary lights and their color purity, and at appropriate dominant wavelengths, high purity primary lights can achieve a wider color gamut. Therefore, at an appropriate wavelength, a smaller full width half maximum FWHM value means a higher color purity, a wider color gamut, and a higher color saturation. As can be seen from the seventh content of the table and fig. 5, when the bubble diameter of the micro bubbles contained in the light diffusion plate is controlled by reducing the temperature of the front end of the T-die in the foaming extrusion process, the micro bubbles can be used to reflect, scatter or refract the passing LED light source, and different bubble diameters can obtain different effects. When the bubble diameter is smaller than 400 μm, the center wavelength of the sample of the light diffusion plate in example 6, both before and after the pressing plate, is shifted backward by about 4-5 nm, and the effect of narrowing the wavelength is achieved, so that the color gamut is wider. Specifically, the wavelength of the organic dye No. 2 of example 6 was 525nm before the plate pressing and 530nm after the plate pressing, that is, shifted 5nm backward; at the same time, the half-width value is narrowed from 31nm before the pressing plate to 37nm after the pressing plate, which corresponds to 4nm. Similarly, the front wavelength of the plate for the organic dye number 6 of example 6 was 626nm, and the rear wavelength of the plate was 630nm, that is, shifted backward by 4nm; at the same time, the half-width value is also narrowed from 41nm before the pressing plate to 36nm after the pressing plate, which corresponds to narrowing by 5nm. When the average bubble diameter of the microbubbles in the light diffusion plate samples was 400 to 600 μm, the wavelengths (half-width values) of the organic dyes of examples 2 and 6 were not narrowed, but the center wavelength was shifted about 2 to 3nm rearward in the light diffusion plate samples of examples 5 and comparative example 16. When the average bubble diameter of the microbubbles in the light diffusing plate sample is larger than 600 μm, the light diffusing plate sample of example 2 and comparative examples 17 and 18 has no effect of shifting wavelength and narrowing half width at half height.
The applicant has provided a plurality of microstructures on the light-emitting surface of a plurality of different light diffusion plate samples (example 7 and comparative example 19 shown in the following table eight), and when the light source emits light through the light diffusion plate, the average luminance of the light diffusion plate is improved by the uniform dispersion of the microstructures again, and the luminance measurement values are shown in the table eight. The thicknesses of the two light diffusion plate samples (example 7 and comparative example 19) shown in Table eight were 1.491mm and 1.485mm, respectively, both of which were added with 3% of the foaming agent, and both of which were also added with two organic dyes of different wavelengths, one of which was the organic dye of No. 2 (wavelength: 525nm, full width at half maximum FWHM value: 31 nm), and the other of which was the organic dye of No. 6, the wavelength: 626nm, full width at half maximum FWHM value: 41nm.
Table eight: the result of brightness measurement after forming a bright surface or microstructure on the light emitting surface of each light diffusion plate sample by using different rollers in the foaming extrusion process
As is clear from table eight, the light diffusion plate sample of example 7 has a plurality of pyramid-shaped microstructures on the light exit surface, but comparative example 19 does not have the microstructure, and the average luminance value of example 7 is 20020 and higher than the average luminance value 19370 of comparative example 19 on the premise that other processes and material conditions are the same as those of comparative example 19.
The above-described embodiments should not be construed as limiting the applicable scope of the present invention, but rather as limiting the scope of the invention encompassed by the technical spirit and equivalent variations defined by the claims of the present invention. All such equivalent changes and modifications as made by the claims of this invention will not depart from the spirit and scope of the present invention, and are intended to be further embodiments of the present invention.
Claims (13)
1. A light diffusion plate for being combined with a blue light source module and converting blue light into white light, comprising:
a plastic substrate having a light incident surface and a light emergent surface parallel to each other, and a thickness perpendicular to the light incident surface and the light emergent surface; the light incident surface is adjacent to the blue light source module, so that blue light emitted by the blue light source module can be emitted into the plastic substrate through the light incident surface and can generally travel along the thickness direction;
at least one light color conversion material dispersed in the plastic substrate for converting the blue light into white light and emitting the white light from the light emitting surface; the method comprises the steps of,
the micro bubbles are dispersed in the plastic substrate, and can perform at least one of the following functions on the light rays in the plastic substrate: reflection, refraction or scattering can improve the effect of uniform light emission on the white light emitted from the light emitting surface;
Wherein the weight reduction rate of the micro bubbles to the plastic substrate is 15-25%, and the average size of each micro bubble is 60-400 μm; the weight reduction rate has the following calculation formula:
weight reduction (%) = (W1-W2)/W2 x 100%;
W1＝H*(L1*L2*D)；
wherein:
h is the average thickness (mm) of the plastic substrate;
l1 is the length (mm) of the plastic substrate;
l2 is the width (mm) of the plastic substrate;
d is the specific gravity (g/mm) of the raw material of the plastic substrate 3 )；
W1 is the theoretical weight (g) of the plastic substrate, i.e., the weight without the microbubbles;
w2 is the actual weight (g) of the plastic substrate, i.e. the actual weight of the plastic substrate containing the plurality of micro-bubbles is obtained by using a scale;
wherein the micro-bubbles are formed in the plastic substrate by a foaming extrusion process of the light diffusion plate; the size of the micro-bubbles is controlled by the temperature of an extrusion process of the light diffusion plate; in the extrusion process of the light diffusion plate, after uniformly mixing and foaming by an extrusion screw section, reducing the temperature of the front section at the outlet end of a T-shaped die head so as to achieve the effect of cooling and converging the foam cells; wherein the temperature of the front section of the outlet end of the T-shaped die head is reduced by 20-30 ℃;
Wherein the processing temperature of the extrusion screw section for uniform mixing foaming is 220-270 ℃, and the front-stage temperature at the outlet end of the T-shaped die is reduced from 270 ℃ to 240-250 ℃;
wherein, in the extrusion process, a nucleating agent is added to the light diffusion plate to assist in controlling the size of the micro-bubbles; the nucleating agent comprises at least one of the following: calcium carbonate, silica, and calcium oxide; the weight percentage of the nucleating agent added is 0.1% -0.5%.
2. A light diffuser plate according to claim 1, wherein:
the blue light source module is a sub-millimeter light emitting diode (Mini LED) array module capable of emitting the blue light; the wavelength of the blue light is 430-500nm;
the at least one light color conversion material comprises one of the following: organic dye, inorganic fluorescent powder.
3. The light diffuser plate of claim 2, wherein the at least one light color conversion material comprises the organic dye having an emission wavelength of 490-650 nm; the molecule of the organic dye comprises at least one of the following functional groups: azo, nitro, nitroso, carbonyl; the organic dye may comprise at least one of: perylene (Perylene), coumarin (Coumarin), eu (BTFA) 3phen, benzoxazolium dye (dye), rhodamine B (Rhodamine B), pyrelmethene dye (dye), perylene (Perylene) orange, perylene (Perylene) red.
4. The light diffuser plate of claim 2, wherein the at least one light color conversion material comprises two organic dyes, one of the organic dyes having an emission wavelength of 520-530nm and the other organic dye having an emission wavelength of 620-630nm.
5. The light diffusion plate according to claim 2, wherein the organic dye is added in a proportion of 0.0001% to 5%.
6. The light diffusing plate of claim 5, wherein the organic dye is added in a proportion of 0.01% to 0.5%.
7. The light diffuser plate of claim 1, wherein the plastic substrate has a thickness in the range of 0.1mm to 3.0mm; arranging a microstructure layer on the light-emitting surface of the plastic substrate; the surface of the microstructure layer is provided with a plurality of microstructures consisting of convex parts or concave parts; the plurality of microstructures may be one of: round, irregular foggy, amoeba, pyramidal.
8. The light diffuser plate of claim 7, wherein the plastic substrate has a preferred thickness in the range of 0.2mm to 2.0mm; the light incident surface is one of the following: a mirror or another microstructure layer without the microstructure; the microstructure layer of the light-emitting surface is provided with a plurality of pyramid microstructures.
9. A method of manufacturing a light diffusion plate, comprising:
putting a base material of a plastic substrate and at least one light color conversion material forming the light diffusion plate into foaming extrusion processing equipment through a feed inlet;
uniformly mixing and foaming at a common processing temperature suitable for polycarbonate in an extrusion screw section of the foaming extrusion process equipment;
extruding the uniformly mixed and foamed base material from the extruding screw section into a plate through a T-shaped die of the foaming extrusion process equipment; and
after the plate is rolled and formed by a roller module of the foaming extrusion processing equipment and cooled, the cooled light diffusion plate is sent out from a discharge hole of the foaming extrusion processing equipment;
the method is characterized in that: after the base material and the light color conversion material are uniformly mixed and foamed in the extrusion screw section, the temperature of the front section is reduced by 20-30 ℃ at an outlet end of the T-shaped die so as to cool and converge the size of a plurality of micro bubbles contained in the plastic substrate to be within the range of 60-400 mu m;
wherein the weight reduction rate of the micro bubbles to the plastic substrate is 15-25%, and the average size of each micro bubble is 60-400 μm; the weight reduction rate has the following calculation formula:
Weight reduction (%) = (W1-W2)/W2 x 100%;
W1＝H*(L1*L2*D)；
wherein:
h is the average thickness (mm) of the plastic substrate;
l1 is the length (mm) of the plastic substrate;
l2 is the width (mm) of the plastic substrate;
d is the specific gravity (g/mm) of the raw material of the plastic substrate 3 )；
W1 is the theoretical weight (g) of the plastic substrate, i.e., the weight without the microbubbles;
w2 is the actual weight (g) of the plastic substrate, i.e. the actual weight of the plastic substrate containing the plurality of micro-bubbles is obtained by using a scale;
wherein, besides the base material and the at least one light color conversion material, a foaming agent, a nucleating agent and a dispersing agent are also put into a foaming extrusion process device through the feed inlet for uniform mixing and foaming;
the general processing temperature for polycarbonate is between 220-270 ℃, and the temperature of the previous stage process of the T-die is 270 ℃, and the temperature of the previous stage at the outlet end of the T-die is reduced from 270 ℃ to between 240-250 ℃;
the nucleating agent comprises at least one of the following: calcium carbonate, silica, and calcium oxide; the weight percentage of the nucleating agent added is 0.1% -0.5%;
the at least one light color conversion material comprises one of the following: organic dye, inorganic fluorescent powder;
The foaming agent comprises one of the following components: 5-basic tetrazole, azo dicarbonate;
the diffusing agent comprises diffusing particles made of at least one of the following materials: calcium carbonate, silica, titanium dioxide, silicone resin microparticles, polymethyl methacrylate microparticles; the weight percentage of the dispersing agent added is 0.1% -10%.
10. The method of claim 9, wherein the at least one light color conversion material comprises the organic dye having an emission wavelength of 490-650 nm; the molecule of the organic dye comprises at least one of the following functional groups: azo, nitro, nitroso, carbonyl; the organic dye may comprise at least one of: perylene (Perylene), coumarin (Coumarin), eu (BTFA) 3phen, benzoxazolium dye (dye), rhodamine B (Rhodamine B), pyrethoquinone dye (dye), perylene (Perylene) orange, perylene (Perylene) red; the organic dye is added in the proportion of 0.0001-5%.
11. The method according to claim 9, wherein the at least one light-color conversion material comprises two organic dyes, wherein one of the organic dyes has an emission wavelength of 520-530nm and the other organic dye has an emission wavelength of 620-630nm; the organic dye is added in the proportion of 0.01-0.5%.
12. The method of manufacturing a light diffusing plate according to claim 9, wherein the thickness of the plastic substrate is in a range of 0.2mm to 2.0mm; arranging a microstructure layer on a light-emitting surface of the plastic substrate; the surface of the microstructure layer is provided with a plurality of microstructures consisting of convex parts or concave parts; the plurality of microstructures may be one of: round, irregular foggy, amoeba, pyramidal; a light incident surface of the plastic substrate is one of the following: a mirror or another microstructured layer that does not have the microstructure.
13. The method of claim 9, wherein the plastic substrate comprises a base material of amorphous or semi-crystalline plasticized material comprising at least one of: polycarbonates (PC), polystyrene, polymethyl methacrylate (PMMA), polyethylene, polypropylene, polyethylene terephthalate; the plastic substrate has one of the following structures: polymethyl methacrylate (PMMA) single-layer plate, polycarbonate (PC) single-layer plate, PMMA/PC double-layer composite plate, PMMA/PC/PMMA three-layer composite plate or other polymer material single-layer or other polymer material multi-layer co-extrusion plates with different refractive indexes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010812282.0A CN114077094B (en) | 2020-08-13 | 2020-08-13 | Light diffusion plate and method for manufacturing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010812282.0A CN114077094B (en) | 2020-08-13 | 2020-08-13 | Light diffusion plate and method for manufacturing same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114077094A CN114077094A (en) | 2022-02-22 |
| CN114077094B true CN114077094B (en) | 2024-01-30 |
Family
ID=80280575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010812282.0A Active CN114077094B (en) | 2020-08-13 | 2020-08-13 | Light diffusion plate and method for manufacturing same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114077094B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200639486A (en) * | 2005-01-12 | 2006-11-16 | Cree Inc | Solid colloidal dispersions for backlighting of liquid crystal displays |
| TW200719055A (en) * | 2005-11-15 | 2007-05-16 | Entire Technology Co Ltd | Light diffuser having high hardness surface and the manufacturing method thereof |
| CN101596803A (en) * | 2008-06-05 | 2009-12-09 | 颖台科技股份有限公司 | Membrane structure and manufacture method thereof |
| JP2010280523A (en) * | 2009-06-03 | 2010-12-16 | Konica Minolta Opto Inc | Fluorescent substance-dispersed glass and method for producing the same |
| WO2016046715A1 (en) * | 2014-09-25 | 2016-03-31 | Università Degli Studi Di Trento | Method for manufacturing porous scaffolds for biomedical uses and scaffolds thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3161553A1 (en) * | 2014-06-26 | 2017-05-03 | Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. | Emitting film with improved light-out coupling |
| CN106896632A (en) * | 2015-12-03 | 2017-06-27 | 精工爱普生株式会社 | Fluorophor, Wavelength changing element, light supply apparatus and projecting apparatus |
-
2020
- 2020-08-13 CN CN202010812282.0A patent/CN114077094B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200639486A (en) * | 2005-01-12 | 2006-11-16 | Cree Inc | Solid colloidal dispersions for backlighting of liquid crystal displays |
| TW200719055A (en) * | 2005-11-15 | 2007-05-16 | Entire Technology Co Ltd | Light diffuser having high hardness surface and the manufacturing method thereof |
| CN101596803A (en) * | 2008-06-05 | 2009-12-09 | 颖台科技股份有限公司 | Membrane structure and manufacture method thereof |
| JP2010280523A (en) * | 2009-06-03 | 2010-12-16 | Konica Minolta Opto Inc | Fluorescent substance-dispersed glass and method for producing the same |
| WO2016046715A1 (en) * | 2014-09-25 | 2016-03-31 | Università Degli Studi Di Trento | Method for manufacturing porous scaffolds for biomedical uses and scaffolds thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114077094A (en) | 2022-02-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7866872B2 (en) | Light guide plate, light guide plate unit, and planar lighting device | |
| US7213933B2 (en) | Direct type backlight module of diffuser plate and its manufacturing method thereof | |
| CN101622494A (en) | Light emitting element and liquid crystal display device | |
| CN101334138A (en) | Mini lightbar illuminators for LCD displays | |
| CN113156708B (en) | Quantum dot diffusion plate for preventing quantum dots from being dissipated by heating, manufacturing method and backlight module | |
| CN102478187A (en) | Display backlight module and manufacturing method thereof | |
| CN102171506B (en) | Light guide plate | |
| TW200949381A (en) | Hollow backlight with structured films | |
| KR20080082534A (en) | White surface light source and liquid crystal display | |
| KR101731762B1 (en) | Manufacturing technique of diffuser plate that use luminous powder | |
| US20060110115A1 (en) | Polycarbonate resin light diffusion plate | |
| US7470038B2 (en) | Diffuser having optical structures | |
| JPWO2005096036A1 (en) | Reflective sheet and manufacturing method thereof | |
| US8524833B2 (en) | High-efficiency light diffusing polymeric film and manufacturing method thereof | |
| CN114077094B (en) | Light diffusion plate and method for manufacturing same | |
| JP2010072131A (en) | Light diffusion plate, optical sheet, backlight unit and display apparatus | |
| US11309508B2 (en) | Multi-functional optical composite board having quantum dots of high uniformity | |
| TWI753842B (en) | Light diffusion plate and method for manufacturing the same | |
| US20220049836A1 (en) | Light Diffusion Plate And Method For Manufacturing The Same | |
| JP2008081563A (en) | Light diffusion/reflection sheet | |
| CN102072439B (en) | Light source module and backlight device | |
| JP2010086669A (en) | Surface lighting device | |
| US11829031B1 (en) | Multilayer light diffuser plate and method for manufacturing the same | |
| CN218630256U (en) | Optical function board | |
| CN117169999A (en) | Multi-layer light diffusion plate and method for manufacturing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |