Backlight module and its preparation methodTechnical field
The present invention relates to a kind of lcd technology, more particularly to backlight module and preparation method thereof.
Background technology
Liquid crystal display (LCD) has the advantages that fuselage is thin, low in energy consumption, radiationless, is widely used, for example, moveMobile phone, digital camera, computer, television screen etc..Liquid crystal display on existing market is most of for backlight liquidCrystal display, it includes liquid crystal display and backlight module, and liquid crystal panel is oppositely arranged with backlight module, and backlight module is carried for liquid crystal displayFor light source.Liquid crystal display shows figure and color by being modulated to the light that backlight module sends.
Fig. 1 shows a kind of existing backlight module.This backlight module is including square backboard 4, in backboard 4And the glue frame 3, circular by glue frame 3 and the light guide plate in backboard 4 is installed on by glue frame 3 fitted with each madial wall of backboard 42, the lamp bar 5 of the one end of light guide plate 2 is arranged on, the diffusion sheet 7 on light guide plate 2 is covered in, and be covered in the reflection on diffusion sheet 7Type polaroid 8.Black double-sided glue 6 bonds together backlight module and liquid crystal display 1, and edge to backlight module 6 hidesLight.Light-emitting component (not shown) is provided with lamp bar 5.The light that light-emitting component sends incides leaded light from the side of light guide plate 2In plate 2.These light, by being projected from the exiting surface of light guide plate 2 after one or many reflection, then pass through and expand in light guide plate 2Discrete piece 7 is atomized.Reflection type polaroid 8 is filtered into polarized light transmission to liquid crystal display 1 to the light that part is atomized again, a partThe light being atomized is reflected to diffusion sheet 7.Glue frame 3, backboard 4, black double-sided glue 6 are non-reflective, directive glue frame 3, backboard 4, blackThe light of color double faced adhesive tape 6 is absorbed, and light is largely leaked from there, so results in backlight efficiency low.Backlight efficiencyLiquid crystal display power consumption, lifting use cost can be lowly lifted, portable display cruising time is reduced, is reduced outdoor readableProperty.
The content of the invention
The technical problems to be solved by the invention are how to improve the backlight efficiency of backlight module.
For above-mentioned technical problem, the present invention proposes a kind of backlight module, and it includes：Light guide plate, one plate face isExiting surface；Reflectance coating, reflectance coating includes the facial area being covered on the exiting surface, wherein, it is provided with only in the facial areaCan transmission-polarizing light reflected light grid region, the reflecting surface of the reflectance coating is towards the light guide plate.
In a specific embodiment, the reflecting grating area is located at the middle part of exiting surface, and the reflectance coating is covered inThe part at exiting surface edge forms the shading region for shading.
In a specific embodiment, a side of light guide plate is incidence surface, and the reflectance coating also includes covering successivelyThe multiple side areas covered on each side of the light guide plate except incidence surface.
In a specific embodiment, the light guide plate also includes the back side relative with the exiting surface, the reflectionFilm also includes the back panel being covered on the back side.
In a specific embodiment, the reflectance coating includes transparent flexible board and is sequentially laminated on flexible boardTransparent dielectric layer and metallic reflector, the flexible board abuts against with the light guide plate, and the metallic reflector is described anti-The part penetrated in grating region is arranged to wiregrating.
In a specific embodiment, the scope value in the cycle of the wiregrating is 20~500nm, and its dutycycle is0.1~0.9.
In a specific embodiment, the material of the transparent dielectric layer include SiO2, SiO, MgO, Si3N4, TiO2,One or more in Ta2O5.
In a specific embodiment, the material of metallic reflector uses Al, Ag or Au.
The invention allows for a kind of method for making backlight module, comprise the following steps：
S10：Transparent dielectric layer is deposited in a plate face of flexible board；
S20：Metallic reflector is deposited on transparent dielectric layer；
S30：Wiregrating is formed after carrying out patterned process to metallic reflector；
S40：Another plate face of flexible board is connected on light guide plate, and causes that wiregrating is covered in the exiting surface of light guide plateOn.
In a specific embodiment, metallic reflector is carried out at patterning using photoetching process in step s 30Reason.
Light from the incidence surface incidence light guide plate of light guide plate, reflect by directive reflected light grid region after being reflected through one or manyGrating region is only capable of transmission-polarizing light and reflects other light, and thus these light can be recycled.Using the back of the body of this structureLight module can greatly improve the utilization rate emitted beam to luminescent device, and then improve brightness and the backlight effect of backlight moduleRate.
Brief description of the drawings
The invention will be described in more detail below based on embodiments and refering to the accompanying drawings.Wherein：
Fig. 1 is a kind of complete section schematic diagram of LCDs of the prior art；
Fig. 2 is the complete section schematic diagram of the backlight module in a kind of embodiment of the invention；
Fig. 3 is the schematic top plan view of the backlight module in a kind of embodiment of the invention；
In the accompanying drawings, identical part uses identical reference.Accompanying drawing is not drawn according to actual ratio.
Specific embodiment
Below in conjunction with accompanying drawing, the invention will be further described.
As shown in Fig. 2 in the present embodiment, backlight module 10 include light guide plate 11, the reflectance coating 12 of covering light guide plate 11,The luminescent device 19 of the one end of light guide plate 11 is arranged on, the glue frame 18 of light guide plate 11 and luminescent device 19 is accommodated and is covered in leaded lightThe diffusion sheet 17 on the top of plate 11.Luminescent device 19 can be adhered in glue frame 18.Luminescent device 19 switches on power backward light guide plate11 emit beam.Light is in the light guide plate 11 by once or multilayer refraction and directive diffusion sheet 17, light guide plate being projected in lightPolarised light is filtered into when 11.Diffusion sheet 17 is atomized the polarised light.
Light guide plate 11 is transparency carrier.Light guide plate 11 generally uses rectangular slab.Reflectance coating 12 wraps up light guide plate 11.Reflectance coating12 reflecting surface is minute surface.The reflecting surface of reflectance coating 12 is towards light guide plate 11.Light guide plate 11 is generally by higher transparent of refractive indexMaterial is made.The transparent material can be the makrolon or polymethyl methacrylate of optical grade.Light guide plate 11 is substantially squareThe platy structure of shape.One plate face of light guide plate 11 is exiting surface 31, and another plate face relative with exiting surface 31 is the back side.LeadThe back side of tabula rasa 11 is provided with intensive reflective site.Reflective site is usually disposed as outwardly salient point array.Light guide plate11 each side and exiting surface 31 are smooth.One side of light guide plate 11 is incidence surface 32.
As shown in figure 3, reflectance coating 12 is covered on light guide plate 11.Reflectance coating 12 is covered in light guide plate 11 except incidence surface 32On each face.In the present embodiment, reflectance coating 12 include flexible board 16, the transparent dielectric layer 30 that is covered on flexible board 16 andIt is covered in the metallic reflector 13 on transparent dielectric layer 30.Flexible board 16 is abutted against with light guide plate 11.Flexible board 16 is using transparentMaterial is made, for example resin material.Transparent dielectric layer 30 is deposited on flexible board 16.The material of transparent dielectric layer 30 includesSiO2、SiO、MgO、Si3N4、TiO2、Ta2O5In one or more.Imaginary part of the metallic reflector 13 preferably using refractive index is bigMetal material, for example, using the one kind in Al, Ag, Au.Metallic reflector 13 is deposited on transparent dielectric layer 30.In this realityApply in example, the two sides of metallic reflector 13 is reflecting surface, it is only necessary to by therein one facing to light guide plate 11.
Reflectance coating 12 includes facial area 41, back panel 43 and multiple sides area 42.The facial area 41 of reflectance coating 12 is coveredOn the exiting surface 31 of light guide plate.Reflected light grid region 14 and shading region 15 are provided with facial area 41.In reflected light grid region 14Interior metallic reflector 13 is arranged to wiregrating.Wiregrating is arranged side by side and evenly spaced metal wire 20 for a plurality of.The width of metal wire 20Degree is identical.The slit 21 of hollow out is formed between adjacent two metal line 20.It is preferably to be parallel to each other between many metal lines 20 and setsPut.Wavelength of the width of slit 21 less than the light that luminescent device 19 sends.The back panel 43 of reflectance coating 12 is covered in light guide plate 11The back side on.Multiple side areas 42 of reflectance coating 12 are respectively overlay in light guide plate 11 except on each side of incidence surface.Preferably,Reflectance coating 12 is structure as a whole.
Luminescent device 19 is active light-emitting component.Incidence surface of the luminescent device 19 near light guide plate 11.Luminescent device 19Light emission direction is towards light guide plate 11.In the present embodiment, luminescent device 19 is provided with multiple, and multiple luminescent devices 19 are along entering lightThe bearing of trend in face is arranged successively.The distance between two neighboring luminescent device 19 interval is uniform.Luminescent device 19 is preferably to be sent outThe Light-Emitting Diode of optical diode, more preferably blue light-emitting.
Glue frame 18 is configured to disk-like structure.In the present embodiment, glue frame 18 is configured to square disc shape.Glue frame 18 accommodates light guide plate11 and luminescent device 19.Luminescent device 19 is preferably mounted on the madial wall of glue frame 18.Luminescent device 19 can be bonded inIn glue frame 18.Glue frame 18 is made using elasticity or flexible material, and cushioning effect is played to external force.Glue frame 18 wraps large areaReflectance coating 12, is avoided that reflectance coating 12 is scraped off.
Diffusion sheet 17 is covered on the reflectance coating 12 of exiting surface 31.Diffusion sheet 17 can be bonded in reflectance coating 12On.Diffusion sheet 17 includes a large amount of transparent particles.So, can be reflected when light passes through transparent particle, light beam is repeatedly through thoroughlyScattered to all directions after bright particulate.It is atomized after light passes through diffusion sheet 17, the light after atomization is softer, it is more equal to be distributedIt is even.
The power supply of luminescent device 19 is connected, the light that luminescent device 19 sends is injected from the incidence surface 32 of light guide plate 11.HairThe light beam that optical device 19 sends enter into light guide plate 11 after directive reflectance coating 12 and reflective site and reflected to all directions.WhenDuring light directive reflected light grid region 14, due to the slit 21 of wiregrating at this width less than light wavelength, polarization direction perpendicular toMetal wire 20 TM polarization luminous energy transmit reflected light grid region 14 and enter into diffusion sheet 17 and be atomized, and polarization direction parallel toThe TE polarised lights of metal wire 20 can be then reflected in light guide plate 11 so as to be recycled.Again because light guide plate 11 is by reflectance coating12 coverings, the light of the back panel 43 of directive reflectance coating 11 can be reflected off and reuse, the side area of directive reflectance coating 1142 light can be reflected off and reuse, and light is only capable of being revealed from incidence surface 32, thus greatly improves to photophoreThe utilization rate that part 19 emits beam, thus, improves brightness and the backlight efficiency of backlight module 10.
Preferably, reflected light grid region 14 is located at the middle part of exiting surface 31, and shading region is provided with around reflected light grid region 1415.As described in the background art, in the prior art, the edge light leak of liquid crystal display is prevented using black double-sided glue.Black is doubleFace glue absorbs light and causes light utilization low.And shading region 15 is provided with around reflected light grid region 14, shading regionThe light at the edge of exiting surface 31 can be reflected back in light guide plate 11 and recycled by 15, so both be avoided that liquid crystal display edge light leakThe utilization rate of light is improve again.
Preferably, the scope value in the cycle of wiregrating is 20~500nm, and its dutycycle is 0.1~0.9.The cycle of wiregratingRefer to the width sum of the width with wall scroll slit 21 of single metal line 20.Dutycycle refers to the width and wall scroll of single metal line 20The ratio between width of slit 21.So, the transmitted light of the outgoing of reflected light grid region 14 has particularly apparent polarization property.
A kind of method for making above-mentioned backlight module 10 is described below, the method is comprised the following steps：
S10：Transparent dielectric layer 30 is deposited in a plate face of flexible board 16；
Transparent dielectric layer 30 is deposited in a plate face of flexible board 16, the step can be excellent with physical gas-phase depositionChoosing uses vacuum evaporation process.
S20：Metallic reflector 13 is deposited on transparent dielectric layer 30；
The step can be with physical gas-phase deposition, it is preferred to use vacuum evaporation process or sputter coating process.
S30：Wiregrating is formed after carrying out patterned process to metallic reflector 13；
Patterned process is carried out to metallic reflector 13 using photoetching process in the step.In the present embodiment, first in goldCoated with nano imprint lithography glue-line on category reflecting layer 13；Then by the metallic mold for nano-imprint imprint lithography glue-line of volume to volume withReflected light grid region 14 forms photoresist grating；Etching technics is used to etch metallic reflector 13 to etch wiregrating again；Finally goExcept photoresist.
S40：Another plate face of flexible board 16 is connected on light guide plate 11, and causes that wiregrating is covered in light guide plate 11In light extraction.
Reflectance coating 12 is folded, flexible board 16 is mutually bonded with light guide plate 11.By the facial area 41 of reflectance coating 12Alignd with the exiting surface 31 of light guide plate, back panel 43 is alignd with the back panel 43 of light guide plate 11, multiple side areas 42 and light guide plateThree sides correspondence align.
The making production efficiency of backlight module 10 is high in this way, and step is simple.
Although by reference to preferred embodiment, invention has been described, is not departing from the situation of the scope of the present inventionUnder, various improvement can be carried out to it and part therein can be replaced with equivalent.Especially, as long as in the absence of structure punchingProminent, the every technical characteristic being previously mentioned in each embodiment can combine in any way.The invention is not limited in textDisclosed in specific embodiment, but all technical schemes including falling within the scope of the appended claims.