U.S. patent application number 17/071380 was filed with the patent office on 2021-01-28 for backlight module and display device.
This patent application is currently assigned to BEIJING BOE OPTOELECTRONICS TECHNOLOGY CO., LTD.. The applicant listed for this patent is BEIJING BOE OPTOELECTRONICS TECHNOLOGY CO., LTD., BOE TECHNOLOGY GROUP CO., LTD.. Invention is credited to Zewen GAO, Yutao HAO, Pei QIN, Haiwei SUN, Shuo WANG, Ming ZHAI, Shubai ZHANG.
Application Number | 20210026204 17/071380 |
Document ID | / |
Family ID | 1000005150489 |
Filed Date | 2021-01-28 |
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United States Patent
Application |
20210026204 |
Kind Code |
A1 |
GAO; Zewen ; et al. |
January 28, 2021 |
BACKLIGHT MODULE AND DISPLAY DEVICE
Abstract
A backlight module and a display device are disclosed, and the
backlight module includes: a light source component, a wavelength
selection film, and a first light emitting film laminated in
sequence. The light source component is configured to emit light of
a first wavelength range, the wavelength selection film transmits
the light of the first wavelength range and reflect at least light
of a second wavelength range, the second wavelength range does not
coincide with the first wavelength range, and the first light
emitting film is configured to excite and emit blue light under an
illumination of the light of the first wavelength range.
Inventors: |
GAO; Zewen; (Beijing,
CN) ; HAO; Yutao; (Beijing, CN) ; ZHANG;
Shubai; (Beijing, CN) ; SUN; Haiwei; (Beijing,
CN) ; ZHAI; Ming; (Beijing, CN) ; QIN;
Pei; (Beijing, CN) ; WANG; Shuo; (Beijing,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BEIJING BOE OPTOELECTRONICS TECHNOLOGY CO., LTD.
BOE TECHNOLOGY GROUP CO., LTD. |
Beijing
Beijing |
|
CN
CN |
|
|
Assignee: |
BEIJING BOE OPTOELECTRONICS
TECHNOLOGY CO., LTD.
Beijing
CN
BOE TECHNOLOGY GROUP CO., LTD.
Beijing
CN
|
Family ID: |
1000005150489 |
Appl. No.: |
17/071380 |
Filed: |
October 15, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16669953 |
Oct 31, 2019 |
|
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17071380 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 2202/36 20130101;
G02F 1/133603 20130101; G02F 1/133614 20210101; G02F 1/133607
20210101; G02F 1/133606 20130101 |
International
Class: |
G02F 1/13357 20060101
G02F001/13357 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 11, 2019 |
CN |
201910287280.1 |
Claims
1-20. (canceled)
21: A backlight module, comprising: a light source component, a
wavelength selection film, and a first light emitting film
laminated in sequence, wherein the light source component is
configured to emit at least light of a first wavelength range, the
wavelength selection film is configured to transmit the light of
the first wavelength range and reflect at least light of a second
wavelength range, the second wavelength range does not coincide
with the first wavelength range, and the first light emitting film
is configured to excite and emit blue light under an illumination
of the light of the first wavelength range.
22: The backlight module of claim 21, wherein the light source
component is a near-infrared light source component, and the first
wavelength range is a near-infrared wavelength range.
23: The backlight module of claim 22, wherein the first wavelength
range is a range of 970 to 980 nm.
24: The backlight module of claim 21, wherein the first light
emitting film is an up-conversion light emitting film comprising
up-conversion light emitting particles and a transparent polymer
material.
25: The backlight module of claim 24, wherein a material of the
up-conversion light emitting particles comprises NaYF4
nanoparticles doped at a mass ratio of Yb:Tm of 20%:0.5%, and the
transparent polymer material is polymethyl methacrylate.
26: The backlight module of claim 24, wherein the up-conversion
light emitting particles have a particle size of 10 to 30 nm.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Chinese Patent
Application No. 201910287280.1 filed on Apr. 11, 2019, the entire
disclosure of which is incorporated herein by reference in its
entirety as part of the present application.
TECHNICAL FIELD
[0002] Embodiments of the present disclosure relate to a field of
liquid crystal display devices, and more particularly to a
backlight module and a display device.
BACKGROUND
[0003] A backlight module is a module for providing a backlight for
a liquid crystal display device (LCD), and is an important
component of the LCD. A portion of light emitted by the backlight
module is reflected by a prism film toward a light source
component, and then reflected by a white oil on a surface of the
light source component. so that the reflected portion of the light
is emitted out from the backlight module. However, the reflectance
of the white oil to the light is only 80%, so there are problems of
light loss and low light efficiency.
SUMMARY
[0004] The embodiments of the present disclosure provide a
backlight module, including: a light source component, a wavelength
selection film, and a first light emitting film laminated in
sequence. The light source component is configured to emit at least
light of a first wavelength range. The wavelength selection film is
configured to transmit the light of the first wavelength range and
reflect at least light of a second wavelength range, and the second
wavelength range does not coincide with the first wavelength range.
The first light emitting film is configured to excite and emit blue
light under an illumination of the light of the first wavelength
range.
[0005] For example, the light source component is an ultraviolet
light source component, and the first wavelength range is an
ultraviolet wavelength range.
[0006] For example, the first wavelength range is a range of 254 to
365 nm.
[0007] For example, the first light emitting film is a photonic
crystal film including photonic crystal microspheres.
[0008] For example, the photonic crystal micrspheres are
microspheres, respective one of which comprises a core comprising
polystyrene and a shell comprising a copolymer of methyl
methacrylate and fluorescamine derivative.
[0009] For example, the photonic crystal microspheres have a
particle size of 170 to 210 nm.
[0010] For example, the light source component is a near-infrared
light source component, and the first wavelength range is a
near-infrared wavelength range.
[0011] For example, the first wavelength range is a range of 970 to
980 nm.
[0012] For example, the first light emitting film is an
up-conversion light emitting film comprising up-conversion light
emitting particles and a transparent polymer material.
[0013] For example, a material of the up-conversion light emitting
particles comprises NaYF4 nanoparticles doped at a mass ratio of
Yb:Tm of 20%:0.5%, and the transparent polymer material is
polymethyl methacrylate.
[0014] For example, the up-conversion light emitting particles have
a particle size of 10 to 30 nm.
[0015] For example, the wavelength selection film is a laminated
film comprising ZnSe nano-films and SiO.sub.2 nano-films that are
sequentially and repeatedly laminated.
[0016] For example, a total number of layers of the ZnSe nano-films
and the laminated SiO.sub.2 nano-films that are sequentially and
repeatedly laminated is 300 to 800.
[0017] For example, the backlight module further includes a second
light emitting film laminated on a light emitting side of the first
light emitting film. The second light emitting film is configured
to excite and emit red and green light under an illumination of the
blue light, so as to emit white light by mixing the red light and
the green light with the blue light.
[0018] For example, the second light emitting film is a quantum dot
film or a phosphor film.
[0019] For example, the backlight module further includes a prism
film laminated on a light emitting side of the second light
emitting film.
[0020] The embodiments of the present disclosure provide a
backlight module, including a light source component, a wavelength
selection film. a first light emitting film, a second light
emitting film. and a prism film laminated in sequence. The light
source component is configured to emit at least light of a first
wavelength range. The wavelength selection film is configured to
transmit the light of the first wavelength range and reflect at
least light of a second wavelength range, and the second wavelength
range does not coincide with the first wavelength range. The first
light emitting film is configured to excite and emit blue light
under an illumination of the light of the first wavelength range.
The second light emitting film is laminated on a light emitting
side of the first light emitting film and is configured to excite
and emit red light and green light under an illumination of the
blue light, so as to emit white light by mixing the red light and
the green light with the blue light.
[0021] For example, the light source component includes a
mini-LED.
[0022] For example, the backlight module further includes a
reflection layer disposed on a side of the light source component
away from the wavelength selection film.
[0023] The embodiments of the present disclosure provide a display
device including a backlight module, the backlight module
comprises: a light source component, a wavelength selection film,
and a first light emitting film laminated in sequence, the light
source component is configured to emit at least light of a first
wavelength range, the wavelength selection film is configured to
transmit the light of the first wavelength range and reflect at
least light of a second wavelength range, the second wavelength
range does not coincide with the first wavelength range, and the
first light emitting film is configured to excite and emit blue
light under an illumination of the light of the first wavelength
range.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The present invention will become more fully understood from
the detailed description given hereinafter and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention and wherein:
[0025] FIG. 1 is a schematic structural view of a backlight module
provided by at least one embodiment of the present disclosure;
[0026] FIG. 2 is a schematic structural view of a wavelength
selection film provided by at least one embodiment of the present
disclosure;
[0027] FIG. 3 is a schematic view of the reflectance to the light
of a wavelength selection film provided by at least one embodiment
of the present disclosure;
[0028] FIG. 4 is a schematic view of the reflectance to the light
of another wavelength selection film provided by at least one
embodiment of the present disclosure.
DETAILED DESCRIPTION
[0029] In order to make objects, technical details and advantages
of the embodiments of the invention apparent, the technical
solutions of the embodiments will be described in a clearly and
fully understandable way in connection with the drawings related to
the embodiments of the present disclosure. Apparently, the
described embodiments are just a part but not all of the
embodiments of the present disclosure. Based on the described
embodiments herein, those skilled in the art can obtain other
embodiment(s), without any inventive work, which should be within
the scope of the present disclosure.
[0030] Unless otherwise defined, all the technical and scientific
terms used herein have the same meanings as commonly understood by
one of ordinary skill in the art to which the present invention
belongs. The terms "first," "second," etc., which are used in the
description and the claims of the present disclosure, are not
intended to indicate any sequence, amount or importance, but
distinguish various components. Also, the terms such as "a," "an,"
etc., are not intended to limit the amount, but indicate the
existence of at least one. The terms "comprise," "comprising,"
"include," "including," etc., are intended to indicate that the
elements or the objects stated before these terms encompass the
elements or the objects and equivalents thereof listed after these
terms, but do not preclude other elements or objects. The phrases
"connect", "connected", etc., are not intended to be limited to a
physical connection or mechanical connection, but may include an
electrical connection, directly or indirectly. The terms "on,"
"under," "right," "left" and the like are only used to indicate
relative position relationship, and when the absolute position of
the object which is described is changed, the relative position
relationship may be changed accordingly.
[0031] A micro (Mini) LED refers to a flip LED chip for display
with a size between 10 and 200 .mu.m (for example 20 and 80 .mu.m).
Compared to a conventional backlight module, the Mini-LED has a
smaller light mixing distance, so that the brightness uniformity
and the color contrast are improved; and the Mini-LED can be used
with a flexible substrate to achieve a curved surface LCD display
similar to an OLED display effect. Due to the maturity of LCD
technology, the mini-LED has a cost advantage compared with the
OLED. However, the existing mini-LED technology has the following
two problems. First, the light efficiency is low. In the
conventional mini-LED structure, only 80% of the light is reflected
by the white oil of a light panel, so that the light loss is high
and the utilization efficiency of light is low. Second, the light
mixing distance is too large. The existing mini-LED backlight
module is direct type, requiring a certain mixing distance. The
mixing distance can be shortened by increasing the arrangement
density of the chip, but the cost is increased, causing the problem
of large light mixing distance difficult to be solved.
[0032] A photonic crystal is formed by spatially periodic
arrangement of dielectric materials having different dielectric
constants (or refractive index). This periodic structure prevents
light of a certain frequency range from propagating therefrom. This
frequency range is called a photonic band gap, and the
non-propagating light undergoes coherent diffraction on the surface
to produce a structural color. Photonic crystals with ultraviolet
light response characteristic can emit fluorescence under the
excitation of ultraviolet light. Therefore, such photonic crystals
not only have a structural color, but also have a fluorescence
emitting characteristic. When the photonic band gap is matched with
its fluorescence emission spectrum, there is a fluorescence
enhancement effect, and the photonic crystal is assembled by
nano-scale microspheres, each of which can emit fluorescence, so
that a point source of a certain frequency can be converted into a
uniform surface source.
[0033] Up-conversion nanoluminescence is a non-linear luminescence
phenomenon because a short-wavelength light is emitted after two or
more long-wavelength photons are continuously absorbed. Inorganic
rare earth ions are not capable of realizing up-conversion
luminescence alone, and the luminescence is achieved by doping the
matrix material. At present, in the up-conversion nanomaterial
doped with lanthanide elements, the lanthanide ion is a
photosensitive element, and is doped in a suitable host crystal to
emit a laser. Therefore, the modulation of the emission wavelength
of the up-conversion nanoparticles can be achieved by doping with a
suitable lanthanide ion. The up-conversion nano-luminescence has a
narrow half-peak width of the emission peak and a long fluorescence
lifetime, and has been widely used in applications such as
up-conversion lasers, display and biological fluorescent
labels.
[0034] The main purpose of the present disclosure is to provide a
backlight module with a novel structure and a display device, which
can solve the problem of light loss in the backlight module and
achieve the purpose of improving the light efficiency.
[0035] As shown in FIG. 1, the embodiments of the present
disclosure provide a backlight module, including: a light source
component 1, a wavelength selection film 2, a first light emitting
film 3 a second light emitting film 4 and a prism film 5 laminated
in sequence. The light source component is used to emit at least
light of a first wavelength range. The wavelength selection film 2
allows the light of the first wavelength range emitted by the first
source component 1 to pass through, and reflect light of a blue
wavelength band, a red wavelength band and a green wavelength band.
The first light emitting film 3 is capable of exciting and emitting
blue light under the illumination of the light of the first
wavelength range.
[0036] Specifically, the backlight module in the embodiments of the
present disclosure, which is an important component of a liquid
crystal display device (LCD), is used for supplying a sufficient
and uniform light source for the liquid crystal display device, so
that the liquid crystal display device can display the image
normally.
[0037] The light source component 1 is preferably a light panel,
and may be a flexible light panel or a rigid light panel, which may
be selected depending on the need. In addition, the light of the
first wavelength range emitted by the light source component 1 is
matched with the first light emitting film 3, that is, the emitted
light of the first wavelength range can excite the first light
emitting film 3 to make it emit the blue light.
[0038] The wavelength selection film 2 is a film for transmitting
the light of the first wavelength range emitted from the light
source component 1 and reflecting the light of the blue light
wavelength band, the red light wavelength band, and the green light
wavelength band. The wavelength selection film 2 can regulate the
transmission range and the reflection range of the light by
regulating the relationship between the difference of the
refractive index on the film surface and the wavelength. For
example, ZnSe and SiO.sub.2 are used as materials, and the
wavelength selection film 2 is formed by alternately laminating the
ZnSe film and the SiO.sub.2 film, and the specific number of layers
of the laminating films can be selected according to actual need.
At present, three kinds of wavelength selection films have been
commercialized, the first one of which transmits the light in the
wavelength range of 220-350 nm while reflects the light in the
wavelength range of 350-800 nm, the second one of which transmits
the light in the wavelength range of 320-480 nm while reflects the
light in the wavelength range of 480-800 nm, and the third one of
which reflects the light in the wavelength range of 320-480 nm
while transmits the light in the wavelength range of 480-800 nm.
One of the common wavelength selection films has a reflectance of
98% to the light of 400-800 nm wavelength and a reflectance of 15%
to the light of 200-400 nm wavelength.
[0039] For example, the first light emitting film 3 is a blue light
emitting film capable of emitting the blue light under the
excitation of the light of the first wavelength range. That is, the
first light emitting film 3 is adapted to the light source
component 1. For example, the first light emitting film 3 may be a
photonic crystal film or an up-conversion light emitting film.
[0040] The second light emitting film 4 is a film capable of
emitting the red light and the green light under the excitation of
the blue light. For example, the existing red-green light emitting
film 4 can be used, which will not be described in detail in the
present disclosure. The prism film 5 is a film capable of
transmitting light. The parameters such as the prism angle, the
prism distribution or the like of the prism film 5 may configured
according to specific needs. The prism film 5 may also be a
conventional prism film, which will not be described in detail in
the present disclosure.
[0041] In the backlight module provided by the embodiments of the
present disclosure, the wavelength selection film 2 and the first
light emitting film 3 are disposed between the light source
component 1 and the second light emitting film 4. After the light
of the first wavelength range emitted by the light source component
1 passes through the wavelength selection film 2, it is irradiated
on the first light emitting film 3, and the first light emitting
film 3 is excited to emit light of a blue light wavelength band,
i.e., the blue light, which is then irradiated on the second light
emitting film 4. The second light emitting film 4 is excited to
emit light of a red light wavelength band and a green light
wavelength band, i.e., the red light and the green light
respectively, and finally the three kinds of light are mixed to
emit the white light. Because the wavelength selection film 2
allows only the light of the first wavelength range emitted by the
light source component 1 to pass through, the white light reflected
by the prism film 5, which includes the light of the blue light
wavelength band, the red light wavelength band, and the green light
wavelength band, can be totally reflected by the wavelength
selection film 2, and then be transmitted through the prism film 5,
thereby solving the problem that the backlight module has light
loss and low light efficiency. In addition, in the embodiments of
the present disclosure, by providing the first light emitting film
3, the light emitted from the light source component 1 is
irradiated onto the first light emitting film 3 after passing
through the wavelength selection film 2. Because the first light
emitting film 3 is an integral film rather than one or more chips
that emit light, the first light emitting film 3 excites and emits
blue light as a surface light source, which can directly irradiate
on the second light emitting film 4, and make the second light
emitting film 4 emit the red light and the green light, which are
mixed with the blue light to finally generate the white light.
Thus, it is not necessary to provide a certain light mixing space
between the first light emitting film 3 and the second light
emitting film 4, thereby solving the technical problem that the
light mixing distance is too large.
[0042] As shown in FIG. 1, in the specific implementations, the
light source component 1 and the first light emitting film 3 are
adapted to each other, for example:
[0043] In at least one embodiment of the present disclosure, the
light source component 1 is an ultraviolet light source component,
and the first light emitting film 3 is a photonic crystal film.
[0044] Specifically, the photonic crystal is formed by spatially
periodic arrangement of dielectric materials having different
dielectric constants (or refractive index). This periodic structure
prevents light of a certain frequency range from propagating
therefrom. This frequency range is called a photonic band gap, and
the non-propagating light undergoes coherent diffraction on the
surface to produce a structural color. Photonic crystals with a
ultraviolet light response characteristic can emit fluorescence
under the excitation of ultraviolet light. Therefore, such photonic
crystals not only have a structural color, but also have a
fluorescence emitting characteristic. When the photonic band gap is
matched with its fluorescence emission spectrum, there is a
fluorescence enhancement effect. Therefore, in at least one
embodiment of the present disclosure, the photonic crystal film is
selected as the first light emitting film 3, and the ultraviolet
light source component is matched as the light source component 1,
so that the ultraviolet light emitted from the ultraviolet light
source component is irradiated on the photonic crystal film to
enable the photonic crystal film emit blue fluorescence.
[0045] For example, the wavelength of the ultraviolet light emitted
by the light source component 1 is in a range of 254-365 nm; and
the photonic crystal film is assembled with photonic crystal
microspheres having a particle size of 170-210 nm.
[0046] Specifically, the ultraviolet light having a wavelength of
254-365 nm is matched with the photonic band gap of the photonic
crystal film to enable the photonic crystal film to emit the blue
light. The photonic crystal film assembled by the photonic crystal
microspheres with a particle size of 170-210 nm has a photonic band
gap matched with the fluorescence emission spectrum, which can
enhance the fluorescence and further improve the brightness, that
is, increase the brightness of the blue fluorescence emitted by the
photonic crystal film. The particle size of the photonic crystal
microspheres is for example 190 nm. In addition, the photonic
crystal film is assembled by nano-scale microspheres, and each
microsphere can emit fluorescence. Therefore, when ultraviolet
light is irradiated on the photonic crystal film, all photonic
crystal microspheres of the photonic crystal film emit blue
fluorescence, forming a uniform surface light source, shortening
the light mixing distance between the first light emitting film 3
and the second light emitting film 4. The method of assembling a
photonic crystal film by using a photonic crystal microsphere may
include an inkjet printing process and an industrial lifting
assembly process, and thus the photonic crystal produced has a
face-centered cubic structure.
[0047] For example, the photonic crystal microspheres are
microspheres, respective one of which comprises a core comprising
polystyrene and a shell comprising a copolymer of methyl
methacrylate and fluorescamine derivative.
[0048] Specifically, the photonic crystal microspheres provided by
the embodiments of the present disclosure may be manufactured by
the following method, but is not limited to this manufacturing
method:
[0049] 1 g of styrene and 0.006 g of emulsifier sodium lauryl
sulfate are dissolved in 70 mL water, heated with 75.quadrature.
water bath under the protection of nitrogen and a mechanical
stirring at a speed of 350 r/min; 9 mg of sodium persulfate, 130 mg
of ethylene sodium hydrogen sulfate, 9 mg of sodium persulfate are
sequentially added, to initiate polymerization with a reaction time
of 10 min; 19 g of styrene, 0.06 g of sodium lauryl sulfate, 0.06 g
of sodium dodecyl diphenyl ether disulfonate, and a mixture of 0.1
g of hydrogen peroxide and 22.5 g of water are slowly added with a
reaction time of 2 h; 6.25 mg of sodium persulfate, 25 mg of sodium
hydrogen sulfite, 6.25 mg of sodium persulfate are sequentially
added with a reaction time of 15 min; 10 g of methyl methacrylate,
0.0125 g of sodium dodecyl sulfate, 0.0525 g of sodium dodecyl
diphenyloxide disulfonate, 0.075 g of sodium dodecyl diphenyl ether
disulfonate, 0.5 g of fluorescamine derivative, and a mixture of 1
g of acrylic acid and 10 g of water are slowly added with a
reaction time of 2.5 h. Then the polymer photonic crystal
microspheres with a core-shell structure are obtained.
[0050] The added amount of above-mentioned various materials is
only the applicable amount in the manufacturing method. When mass
production is required, the amount of each of the above materials
can be adjusted in an equal proportion, and the parameters such as
the reaction time can also be adjusted.
[0051] In at least one embodiment of the present disclosure, the
light source component 1 is a near-infrared light source component,
and the first light emitting film 3 is an up-conversion light
emitting film.
[0052] Specifically, the up-conversion light emitting film includes
up-conversion light emitting particles, and up-conversion light
emitting particle luminescence is a non-linear luminescence
phenomenon because a short-wavelength light is emitted after two or
more long-wavelength photons are continuously absorbed. Inorganic
rare earth ions are not capable of realizing up-conversion
luminescence alone, and the luminescence is achieved by doping the
matrix material. The lanthanide may be doped in the up-conversion
light emitting particles, and the lanthanide ion is a
photosensitive element, and is doped in a suitable host crystal to
emit a laser. Therefore, the modulation of the emission wavelength
of the up-conversion light emitting particles can be achieved by
doping with a suitable lanthanide ion. In addition, the
up-conversion light emitting particle luminescence is characterized
by a narrow half-peak width of the emission peak and a long
fluorescence lifetime. Thus, under the illumination of the
near-infrared light, the up-conversion light emitting film can emit
the blue light.
[0053] For example, the light source component 1 emits a
near-infrared light having a wavelength of 970-980 nm. The
up-conversion light emitting film comprises up-conversion light
emitting particles having a particle size of 10-30 nm and a
transparent polymer material, in which the transparent polymer
material can be used as a bonding material for up-conversion light
emitting particles. For example, the up-conversion light emitting
particles is uniformly distributed throughout the up-conversion
light emitting film.
[0054] Specifically, for example, the wavelength of the
near-infrared light emitted from the light source member 1 is 980
nm, and the up-converted light emitting particles have a particle
size of 20 nm. Because the up-conversion light emitting film
comprises a mixture of up-conversion light emitting particles
having the particle size of 20 nm and a transparent polymer
material, and the up-conversion light emitting particles are
uniformly distributed, when the near-infrared light is irradiated
on the up-conversion light emitting film, all of the up-conversion
light emitting particles in the up-conversion light emitting film
are excited to form a blue surface light source, which greatly
reduces the mixing distance and reduces the cost of the backlight
module. Further, by modulating the concentration of the
up-conversion light emitting particles in the up-conversion light
emitting film, the intensity of the blue surface light source can
be regulated. Thus, the concentration of the up-conversion light
emitting particles in the up-conversion light emitting film can be
adjusted according to actual need, which is not limited by the
present disclosure.
[0055] For example, the material of the up-conversion light
emitting particles comprises NaYF4 nanoparticles doped at a mass
ratio of Yb:Tm of 20%:0.5%, and the transparent polymer material is
polymethyl methacrylate (PMMA).
[0056] Specifically, the up-conversion light emitting particles
provided by the embodiments of the present disclosure can be
manufactured by the following method, but is not limited to this
manufacturing method:
[0057] 0.24 g of YCl.sub.3.6H.sub.20, 0.078 g of
YbCl.sub.3.6H.sub.2O, and 0.0019 g of TmCl.sub.3.6H.sub.2O are
dissolved in methanol, 6 ml of oleic acid and 15 ml of 1-octadecene
are added in a 100 ml three-necked flask, and the mixed methanol
solution is added, stirred and heated to 80.degree. C. until the
methanol is evaporated. Next, nitrogen gas is supplied to the
reaction vessel for protection, and the temperature is further
raised to 150.degree. C. After being heated for 30 minutes, the
reaction product is cooled to the room temperature. 0.1482 g of
NH.sub.4F and 0.1 g of NaOH are dissolved in methanol and added to
the three-neck flask, stirred for 30 min then heated to 80.degree.
C. Nitrogen gas is continuously supplied after the completion of
the evaporation of the solvent. Then, the temperature is raised to
300.degree. C. at a heating rate of 15.degree. C./min, the air is
condensed and maintained for 60 min, and finally cooled to the room
temperature. The nitrogen gas is turned off, and a yellow-brown
transparent solution is obtained. Then, the obtained solution is
poured into ethanol to precipitate, and centrifuged to obtain a
white precipitate, which is then dissolved by adding cyclohexane,
and then precipitated with methanol and allowed to stand for 30
min. A precipitate is obtained by centrifugation, and ethanol is
again added thereto. The mixture is centrifuged to obtain
up-conversion light emitting particles. The up-conversion light
emitting particles produced by the above method have a rod-like
structure and a spherical structure and have a diameter of 20 nm.
The up-conversion light emitting particles emit blue light with
wavelengths of 450 nm and 475 nm under the excitation of
near-infrared light with a wavelength of 980 nm.
[0058] In the above-mentioned manufacturing method, the added
amount of above-mentioned various materials is only the applicable
amount in the manufacturing method. When mass production is
required, the amount of each of the above materials can be adjusted
in an equal proportion, and the parameters such as the reaction
time can also be adjusted.
[0059] Specifically, the up-conversion light emitting film provided
by the embodiments of the present disclosure may be manufactured by
the following method, but is not limited to this manufacturing
method:
[0060] A surface modification process is performed on the
up-conversion light emitting particles for the purpose that the
up-conversion light emitting particles can be uniformly mixed with
PMMA in a subsequent film forming process. The surface modification
process is as follows: dissolve 6 mg of the obtained up-converted
light emitting particles in 5 ml of cyclohexane, and add a
hydrochloric acid solution (pH=4) thereto, followed by stirring for
1 hour. Further add acetone and then centrifuge to obtain a white
precipitate which is then dissolved in 5 ml of deionized water.
Then slowly add dropwise 1 ml of ethanol solution containing 60 mg
of Si-PEG into the water solution obtained in the last step and
stir in the meantime. After a reaction time of 12h, the modified
up-conversion light emitting particles are obtained by
centrifugation.
[0061] Preparation of the up-conversion light emitting film is as
follows: first, mix 20 ml of PMMA and 1 ml of NaYF4:20% Yb, 0.5% Tm
in ethanol (concentration range can be 1-6 mg/ml) to obtain a
polymerization precursor, and then add the initiator, 0.25 g of
azobisisobutyronitrile, and stir at 60.degree. C. for 2 h to carry
out prepolymerization. NaYF4:20% Yb, 0.5% means NaYF4 nanoparticles
doped at a mass ratio of Yb:Tm of 20%:0.5%. After that, the
temperature is raised to 80.degree. C., and the polymerization is
completed after 45 minutes of reaction. The product is allowed to
stand for 1 h, the bubbles are discharged, a film is formed by a
spin coating process, and the film is subjected to high temperature
treatment to remove the remaining monomers, thereby finally
obtaining the up-conversion light emitting film. The modulation of
NaYF4:20% Yb, 0.5% Tm can achieve the modulation of blue light
intensity.
[0062] It should be noted that in the above-mentioned manufacturing
method for the up-conversion light emitting film by uniformly
mixing the up-conversion light emitting particles with PMMA, the
amount of above-mentioned various materials is only the applicable
amount in the manufacturing method. When mass production is
required, the amount of each of the above materials can be adjusted
in an equal proportion, and the parameters such as the reaction
time can also be adjusted.
[0063] As shown in FIG. 2 and FIG. 3, in the specific
implementations, the wavelength selection film 2 is a laminated
film comprising ZnSe nano-films and SiO.sub.2 nano-films that are
sequentially and repeatedly laminated, and the parameters of the
film are as shown in Table 1; the total number of layers of the
ZnSe nano-films and the laminated SiO.sub.2 nano-films that are
sequentially and repeatedly laminated is 300 to 800. In addition,
using ZnSe and SiO.sub.2 materials to form the wavelength selection
film 2 is only a preferred method, and is not specifically limited.
The wavelength selection film 2 may also comprises other materials,
as long as they can archive the transmitting of the ultraviolet
light and the near infrared light and the reflecting of the light
in the blue, red, and green wavelength bands.
TABLE-US-00001 TABLE 1 Parameters of film Number of layers 1 2 . .
. 399 400 401 402 . . . 409 410 Material ZnSe SiO.sub.2 . . . ZnSe
SiO.sub.2 ZnSe SiO.sub.2 . . . ZnSe SiO.sub.2 Thickness/nm 57.69
101.49 . . . 57.69 101.49 43.27 76.12 . . . 43.27 76.12 Number of
layers 411 412 . . . 809 810 811 812 . . . 1209 1210 Material ZnSe
SiO.sub.2 . . . ZnSe SiO.sub.2 ZnSe SiO.sub.2 . . . ZnSe SiO.sub.2
Thickness/nm 50.48 88.8 . . . 50.48 88.8 60.58 106.56 . . . 60.58
106.56 Number of layers 1211 1212 . . . 1409 1410 1411 1412 . . .
1809 1810 Material ZnSe SiO.sub.2 . . . ZnSe SiO.sub.2 ZnSe
SiO.sub.2 . . . ZnSe SiO.sub.2 Thickness/nm 66.35 116.71 . . .
66.35 116.71 72.12 126.86 . . . 72.12 126.86
[0064] Specifically, the multilayer ZnSe nano-films 21 and the
multilayer SiO.sub.2 nano-films 22 are sequentially alternately
laminated, and the numbers of the ZnSe nano-films 21 and the
SiO.sub.2 nano-films 22 are equal, that is, the total number of
layer is an even number. The ZnSe nano-film 21 preferably has a
thickness of 40-60 nm, the SiO.sub.2 nano-film 22 preferably has a
thickness of 80 to 130 nm. The specific properties of the
wavelength selection film 2 obtained by the above techniques
conditions are shown in FIG. 3 and FIG. 4, in which FIG. 3 is the
reflection state of the wavelength selection film 2 to the light
with wavelength below 800 nm. It can be seen that the reflectivity
of the wavelength selection film 2 to the ultraviolet light with a
wavelength of 254-365 nm is less than 30%. That is, the
transmission effect is good. And it can be seen that the
reflectivity of the wavelength selection film 2 to the red light
with a wavelength of 620-760 nm, the green light with a wavelength
of 495-570 nm and the blue light with a wavelength of 476-495 nm is
100% or near 100%. That is, the wavelength selection film 2 can be
applied to the backlight module in which the light source component
1 is an ultraviolet light source component, and the first light
emitting film 3 is a photonic crystal film. Further, FIG. 4 is the
reflection state of light the wavelength selection film 2 to light
with wavelength between 350 and 1200 nm. It can be seen that the
reflectivity of the wavelength selection film 2 to the
near-infrared light with a wavelength of 970-980 nm is around 30%.
That is, the transmission effect is good. And it can be seen that
the reflectivity of the wavelength selection film 2 to the red
light with a wavelength of 620-760 nm, the green light with a
wavelength of 495-570 nm and the blue light with a wavelength of
476-495 nm is 100% or near 100%. That is, the wavelength selection
film 2 can be applied to the backlight module in which the light
source component 1 is a near-infrared light source component, and
the first light emitting film 3 is an up-conversion light emitting
film.
[0065] In a specific implementation, the second light emitting film
4 is a quantum dot film or a phosphor film.
[0066] Specifically, quantum dots are invisible to the naked eye,
with extremely tiny inorganic nanocrystals. Once it is stimulated
by light, the quantum dots emit very pure colored light, so the
quantum dot film may be used as the second light emitting film 4
under a controllable cost.
[0067] In addition, the photonic crystal film may be selected from
other phosphors that can emit the blue light under excitation of
the ultraviolet light, such as a mixture of a urethane
group-containing phthalimide and a fluorescamine, or a derivative
of a diphenyl hydrazine and a diphenyl fluorene-based group. The
up-conversion light emitting particles in the up-conversion light
emitting film may be selected from the up-conversion light emitting
particles doped with other lanthanide materials to emit blue
light.
[0068] For example, the light source component 1 provided by at
least one embodiment of the present disclosure may be an LED, a
mini LED, and a micro blue chip, etc., which is not limited by at
least one embodiment of the present disclosure.
[0069] For example, in a backlight module provided by at least one
embodiment of the present disclosure, a side of the light source
component 1 away from the wavelength selection film 2 may be
provided with a reflection layer 6, and the reflection layer 6 may
be formed by coating the reflection material or attaching the
reflection sheet. It should be noted that providing the reflection
layer 6 on the side of the light source component 1 away from the
wavelength selection film 2 can reflect the light escaping from the
light source component 1 to the wavelength selection film 2,
thereby improving light utilization efficiency.
[0070] At least one embodiment of the present disclosure display
device including a backlight. As shown in FIG. 1, the backlight
module includes a light source component 1, a wavelength selection
film 2, a first light emitting film 3, a second light emitting film
4 and a prism film 5 laminated in sequence. The light source
component 1 is configured to emit at least light of a first
wavelength range, the wavelength selection film 2 allows the light
of the first wavelength range emitted by the first source component
1 to pass through, and reflect the light of a blue wavelength band,
a red wavelength band and a green wavelength band. The first light
emitting film 3 is capable of exciting and emitting blue light
under the illumination of the light of the first wavelength range.
The second light emitting film 4 is laminated on a light emitting
side of the first light emitting film 3, and the second light
emitting film 4 is configured to excite and emit red light and
green light under the illumination of the blue light, so as to emit
white light by mixing the red light and the green light with the
blue light. The prism film 5 is laminated on a light emitting side
of the second light emitting film 4.
[0071] Specifically, the backlight module described in this
embodiment can use the backlight module provided in the foregoing
embodiment. The specific implementation structure can be referred
to the related content described in the foregoing embodiment, and
details are not described herein again.
[0072] As shown in FIG. 1. the display device provided by the
embodiments of the present disclosure uses a backlight module in
which the wavelength selection film 2 and the first light emitting
film 3 are provided between the light source component 1 and the
second light emitting film 4. After the light of the first
wavelength range emitted by the light source component 1 passes
through the wavelength selection film 2 it is irradiated on the
first light emitting film 3, and the first light emitting film 3 is
excited to emit light of a blue light wavelength band, i.e., the
blue light, which is then irradiated on the second light emitting
film 4. The second light emitting film 4 is excited to emit light
of a red light wavelength band and a green light wavelength band,
i.e., the red light and the green light, and finally the three
kinds of light are mixed to emit the white light. Because the
wavelength selection film 2 allows only the light of the first
wavelength range emitted by the light source component 1 to pass
through, the white light reflected by the prism film 5, which
includes the light of the blue light wavelength band, the red light
wavelength band, and the green light wavelength band, can be
totally reflected by the wavelength selection film 2, and then be
transmitted through the prism film 5, thereby solving the problem
that the backlight module has light loss and low light efficiency.
In addition, in the embodiments of the present disclosure, by
providing the first light emitting film 3, the light emitted from
the light source component 1 is irradiated onto the first light
emitting film 3 after passing through the wavelength selection film
2. Because the first light emitting film 3 is an integral film
rather than one or more chips that emit light, the first light
emitting film 3 excites and emits blue light as a surface light
source, which can directly irradiate on the second light emitting
film 4, and make the second light emitting film 4 emit the red
light and the green light, which are mixed with the blue light to
finally generate the white light. Thus, it is not necessary to
provide a certain light mixing space between the first light
emitting film 3 and the second light emitting film 4, thereby
solving the technical problem that the light mixing distance is too
large.
[0073] What are described above is related to the illustrative
embodiments of the disclosure only and not limitative to the scope
of the disclosure; the scopes of the disclosure are defined by the
accompanying claims.
* * * * *