CN102537767A - Display backlight module with multilayer multilayer film reflection sheet and manufacturing method thereof - Google Patents

Abstract

The invention provides a display backlight module with multilayer film reflector and a manufacturing method thereof, in particular to a multilayer film reflector composed of a plurality of mutually overlapped high polymer films with different refractive indexes. The embodiment of the display backlight module comprises a backlight source module, such as a direct-type or lateral-type light source, and further comprises a first multilayer film reflector, a second multilayer film reflector and an optical film, wherein the optical film can be a diffusion film.

Description

Display backlight module with multilayer multilayer film reflection sheet and manufacturing method thereof

technical field

The invention relates to a display backlight module with multi-layer film reflection sheets and a manufacturing method thereof, in particular to a display backlight module provided with two or more multi-layer film reflection sheets that can adjust the wavelength range of light sources.

Background technique

Backlight modules applied to liquid crystal display (LCD) panels can be classified into edge type and direct type according to the light source structure.

The structure of the side light source shown in Figure 1, the light source itself may be a cathode fluorescent tube (CCFL) or a light emitting diode (LED), which is arranged on the side of the panel. The side-facing backlight module shown in Fig. 1 is arranged under the liquid crystal display panel 101, and the backlight module usually includes a prism sheet (prism) 102 that helps light diffuse, a diffuser film (diffuser) 103 that helps light uniformity, and a wedge shape. The light guide plate (light guide plate) 104, the light source 105 is arranged on one side of the light guide plate 104, and the backlight module has a reflector (reflector) 106 that can reflect light into the panel at the bottom.

Wherein, the light is emitted by the light source 105, and the light is dispersed in the whole display panel through the light guide plate 104, the downgoing light will be reflected into the panel by the reflective sheet 106, and the upgoing light can pass through the combination of the diffusion film 103 and the prism sheet 102. The optical system uniformizes the light, and the diffusion film 103 can reduce light and dark problems caused by light interference, so that the light entering the liquid crystal display panel 101 can emit light evenly. Among them, each optical element, such as the diffusion film 103 and the light guide plate 104, can produce some diffusion particles or structures on its surface or inside through the process, and through the principle of reflection and refraction, the light is more disordered and the effect of uniformity is improved.

FIG. 2 is a schematic diagram of a direct-lit backlight module in the prior art. The direct-type backlight module is to place light sources such as cathode lamps or light-emitting diodes directly under the liquid crystal display panel 201. The direct-type backlight module includes a prism sheet 202 that helps light diffuse and a diffusion film that helps light uniformity. 203 and a light box 204 with a light source 205 and a reflective structure 206 . Different from the side light source, the direct light source can direct light to the liquid crystal display panel 201. In order to obtain a uniform light source, optical elements such as prism sheets and diffusion films are also required. The surface or interior of the optical elements can also be produced by process Particles or structures for diffusion.

In the prior art, for each optical element used in the backlight module, reference may be made to the optical module of a display disclosed in US Pat. No. 7,763,331, and reference may be made to FIG. 3 for related drawings.

This example shows a liquid crystal display device 30, wherein the main components are the liquid crystal panel 301 and the backlight optical module below it, the optical module includes an optical film 303, a brightness enhancing film (brightnessenhancing film) 305, a light guide plate 307 and a light source 308 on one side thereof , there is a reflective plate 309 under the light guide plate 307 for reflecting the downward light.

The optical film 303 can be a diffusion film, a reflective polarizing film or another brightness enhancement film. In this example, the brightness enhancement film 305 is arranged between the light guide plate 307 and the liquid crystal panel 301. Generally speaking, the upper and lower surfaces of the liquid crystal panel 301 have polarizing films. If there is loss, the brightness enhancement film 305 (such as DBEF, prismatic brightness enhancement film) composed of multi-layer reflective polarizing modules can help improve the brightness of the backlight and save energy consumption.

Contents of the invention

In order to provide a solution different from the optical elements in the prior art backlight module, the present invention proposes a backlight module applied to liquid crystal displays, which includes a side-facing or direct-type backlight module. On the surface, two or more multi-layer reflective sheets are specially provided. The multi-layer reflective sheet is composed of multiple layers of polymer films with different refractive indices and superimposed on each other. It is arranged between the backlight module and the between LCD panels. In one embodiment, there is an additional optical film, such as a diffuser film.

Specifically, the display backlight module according to one aspect of the present invention includes: a side-to-type backlight module; a first multilayer film reflector, arranged between the side-to-type backlight module and a liquid crystal display panel, by It is composed of multiple layers of polymer films with different refractive indices and superimposed on each other, which is designed to reflect or penetrate light with a specific wavelength range by using the interference principle; and a diffusion film attached to the first multi-layer film One side of the reflection sheet uses the microstructure in the film to evenly diffuse the light generated by the side-facing backlight module. Wherein, the side-type backlight module further includes: a side-type light source; a light guide plate coupled to the side-type light source; a reflective sheet arranged on one side of the light guide plate to reflect the side In the light of the type light source, the down-going light entering the light guide plate; a second multi-layer film reflector is arranged on a light-emitting surface of the side-type backlight module, and consists of multiple layers with different refractive indices and superimposed on each other. Composed of high molecular polymer films, which use the interference principle to design reflection or penetration of light with a specific wavelength range; a reflection cavity is defined between the second multi-layer film reflector and the reflector, and the light passes through the reflection cavity Multiple reflections, refractions and scattering are generated inside.

According to a further improved technical solution of the present invention, a surface structure is coated or extruded on one surface of the first multilayer reflective sheet or the second multilayer reflective sheet.

According to a further improved technical solution of the present invention, the surface structure of the first multilayer reflective sheet or the second multilayer reflective sheet further includes a plurality of diffusion particles.

According to a further improved technical solution of the present invention, a diffusion film is attached to the surface of the first multilayer reflective sheet or the second multilayer reflective sheet.

According to a further improved technical solution of the present invention, the diffusion film on the surface has a plurality of diffusion particles.

According to a further improved technical solution of the present invention, the multilayer structure of the first multilayer reflective sheet or the second multilayer reflective sheet further includes an ultraviolet reflective layer that reflects ultraviolet rays.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made through a uniaxial stretching process.

According to the further improved technical solution of the present invention, after the first multilayer reflective sheet or the second multilayer reflective sheet undergoes the uniaxial stretching process, the average transmittance in the spectrum of 400nm to 700nm is between 30% and 90%. between.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made by a biaxial stretching process.

According to the further improved technical solution of the present invention, after the first multilayer reflective sheet or the second multilayer reflective sheet undergoes the biaxial stretching process, the average transmittance in the spectrum of 400nm to 700nm is between 30% and 90% %between.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made through a biaxial stretching process, and the multilayer reflective sheet has polarizing properties.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made through a biaxial stretching process, and the multilayer reflective sheet does not have polarizing properties.

According to a further improved technical solution of the present invention, the display backlight module is applied to a liquid crystal display device, and further includes: a direct-type backlight module, including: a light source; a reflector, coupled to the light source, for reflecting The down-going light generated by refraction of the light from the light source; a second multi-layer film reflector, arranged on a light-emitting surface of the direct-type backlight module, composed of multiple layers of high molecular polymers with different refractive indices and superimposed on each other Composed of thin films, which use the interference principle to design reflection or penetration of light with a specific wavelength range; a reflection cavity is defined between the multi-layer film reflection sheet and the reflection plate, and the light generates multiple reflections and refractions in the reflection cavity and scattering; and a first multi-layer film reflection sheet, which is arranged between the direct-type backlight source module and a liquid crystal display panel, and is composed of multiple polymer films with different refractive indices and superimposed on each other, wherein Using the principle of interference to design reflection or penetration of light with a specific wavelength range; and a diffusion film, attached to one side of the first multi-layer film reflection sheet, using the microstructure in the film to evenly diffuse the direct-type backlight module generated light.

According to the further improved technical solution of the present invention, the light source of the direct-lit backlight module is a light emitting diode array.

According to the further improved technical solution of the present invention, the light-emitting diode array is composed of multiple sets of red, green and blue light-emitting diodes, laser diodes, or light-emitting diodes that excite phosphors with blue light or light-emitting diodes that excite multi-color phosphors with ultraviolet light. Composed of light emitting elements.

According to a further improved technical solution of the present invention, a surface structure is coated or extruded on one surface of the first multilayer reflective sheet or the second multilayer reflective sheet.

According to a further improved technical solution of the present invention, the surface structure of the first multilayer reflective sheet or the second multilayer reflective sheet further includes a plurality of diffusion particles.

According to a further improved technical solution of the present invention, a diffusion film is attached to the surface of the first multilayer reflective sheet or the second multilayer reflective sheet.

According to a further improved technical solution of the present invention, the diffusion film on the surface has a plurality of diffusion particles.

According to a further improved technical solution of the present invention, the multilayer structure of the first multilayer reflective sheet or the second multilayer reflective sheet further includes an ultraviolet reflective layer that reflects ultraviolet rays.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made through a uniaxial stretching process.

According to the further improved technical solution of the present invention, after the first multilayer reflective sheet or the second multilayer reflective sheet undergoes the uniaxial stretching process, the average transmittance in the spectrum of 400nm to 700nm is between 30% and 90% %between.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made by a biaxial stretching process.

According to the further improved technical solution of the present invention, after the first multilayer reflective sheet or the second multilayer reflective sheet undergoes the biaxial stretching process, the average transmittance in the spectrum of 400nm to 700nm is between 30% and 90% %between.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made through a biaxial stretching process, and the multilayer reflective sheet has polarizing properties.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is made through a biaxial stretching process, and the multilayer reflective sheet does not have polarizing properties.

According to another aspect of the present invention, it provides a method for manufacturing a display backlight module, comprising: setting a liquid crystal display panel; setting a backlight module, having a light source and a light-reflecting element; setting a first multilayer film reflector The first multi-layer reflective film is composed of multiple layers of polymer films with different refractive indices and superimposed on each other. It is designed to reflect or transmit light with a specific wavelength by using the principle of interference. range of light; a second multi-layer reflective sheet is provided to be bonded to the backlight module, and the second multi-layer reflective sheet is composed of multiple polymer films with different refractive indices and superimposed on each other. Using the principle of interference to design reflection or penetration of light with a specific wavelength range; and, a reflection cavity is defined between the second multi-layer film reflection sheet and the reflection element in the backlight module, and the light is in the reflection cavity Multiple reflection, refraction and scattering are generated; and an optical film is arranged between the first multilayer film reflection sheet and the second multilayer film reflection sheet.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet and the second multilayer reflective sheet are produced by a co-extrusion process.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet or the second multilayer reflective sheet is also subjected to a uniaxial stretching process to form an optical element with a polarization effect.

According to the further improved technical solution of the present invention, the average transmittance of the first multilayer reflective sheet or the second multilayer reflective sheet produced by the uniaxial stretching process in the spectrum of 400nm to 700nm is between 30% and 90%. between.

According to a further improved technical solution of the present invention, the first multilayer reflective sheet and the second multilayer reflective sheet also undergo a biaxial stretching process, so as to control the The ratio of P-polarization to S-polarization of light from the film reflector.

According to the further improved technical solution of the present invention, the average transmittance of the first multilayer reflective sheet or the second multilayer reflective sheet produced by the biaxial stretching process in the spectrum of 400nm to 700nm is between 30% and 90%. between.

According to the further improved technical solution of the present invention, the backlight module is a side-lit backlight module.

According to the further improved technical solution of the present invention, the backlight source module is a direct-down type backlight source module.

According to the further improved technical solution of the present invention, the light source of the direct-lit backlight module is a light-emitting diode array, and the light-emitting diode array is composed of multiple groups of light-emitting elements with red, green, blue, or other types of light-emitting diodes. .

According to a further improved technical solution of the present invention, a surface structure is formed on a surface of the first multilayer reflective sheet or the second multilayer reflective sheet by a coating process.

According to a further improved technical solution of the present invention, the surface structure has a plurality of diffusion particles.

According to a further improved technical solution of the present invention, the multilayer structure of the multilayer film reflective sheet further includes an ultraviolet reflective layer produced by a process of co-extrusion, coating, sputtering or evaporation.

In particular, in the backlight module of a general liquid crystal display, an optical film for increasing light, increasing diffusion, and uniformity is usually provided, such as the reflective brightness-enhancing film (DBEF) of 3M ^TM Company, or some multi-layer films are used to form multiple The optical film that reflects the light path, or the optical structure that uses the surface structure to generate the diffusion function. One of the multilayer reflectors in the backlight module of the display will replace the reflective brightness enhancement film (DBEF) of 3M ^TM Company, which is commonly used in the backlight module in the prior art, and cooperate with another multilayer reflector to achieve effective mixing. The effect of light and polarized light can be designed by using the principle of interference to reflect or penetrate light with a specific wavelength range.

According to an embodiment, at least the first multilayer reflective sheet and the second multilayer reflective sheet are simultaneously arranged in the backlight module of the liquid crystal display, and the principle of interference between multilayer thin films with different refractive indices in the multilayer reflective sheet is used , set the light to be reflected or transmitted with a specific wavelength range, and a more uniform backlight can be obtained due to the increase in the optical path and multiple reflections.

An embodiment of the display backlight module includes a backlight module, such as a direct-type or side-type light source, and also includes the above-mentioned first and second multi-layer film reflectors, and another optical film.

As far as the light source is concerned, the present invention specifically proposes that it can be applied to a direct-lit backlight module in which the light source is a light-emitting diode array, and the light-emitting diode array can be mainly composed of a plurality of white lights, and can also be selected to be composed of multiple sets of array-type light-emitting diodes. A backlight composed of multiple groups of red, green, and blue color combinations, a combination of blue light-emitting diodes and yellow phosphors, or other types of light-emitting diodes.

The process of the above-mentioned display backlight module is mainly to install a liquid crystal display panel first, and to install a backlight module, and to install two or more multilayer polymer films with different refractive indices and superimposed on each other. A reflective sheet is laminated, and an optical film is pasted, and then combined on a surface of the liquid crystal display panel. The optical film can be a diffusion film.

In particular, the multi-layer reflective sheet can be produced by a co-extrusion process, and can be further processed by a uniaxial stretching process to form an optical element with a polarization effect. Or through a biaxial stretching process, the ratio of P polarization and S polarization of the light passing through the multilayer film reflection sheet can be controlled.

According to the main embodiment described in the present invention, especially the side-light type display backlight module, there is a first multi-layer film reflector, which has the ability to reflect light in a specific wavelength range, and is also combined with a diffusion film, which is combined with the first multi-layer film. Laminate the reflective sheet on the other surface of the LCD panel. The module includes a backlight module, and the optical components mainly include a backlight diffusion film, a second multi-layer reflective sheet, a light source, a light guide plate and a reflective sheet. The second multilayer reflective sheet is arranged on a light-emitting surface of the backlight module, and has the ability to reflect light in a specific wavelength range because of internal interference. A reflective cavity is defined, and light can generate multiple reflections, refraction and scattering in the reflective cavity.

After the above-mentioned first multi-layer reflective sheet or the second multi-layer reflective sheet undergoes a uniaxial stretching process, the average transmittance of the spectrum 400nm-700nm can be between 30% and 90%.

And the first multi-layer reflective sheet or the second multi-layer reflective sheet can be made through a biaxial stretching process, and the average transmittance of the spectrum 400nm-700nm is also between 30% and 90%. The wavelengths of 400nm to 700nm described in the present invention generally refer to the general range of visible light bands, but each person's eye structure will have different perceptions of wavelengths, and the wavelengths of visible light may also be slightly shifted to longer or shorter wavelengths. .

Another embodiment discloses a direct-lit display backlight module, wherein a first multilayer reflective sheet and another second multilayer reflective sheet are provided between the liquid crystal display panel and the light source module, and the two multilayer reflective sheets Other optical films, such as diffusion films, brightness enhancement films, etc., can be arranged between them.

The manufacturing method of the display backlight module includes setting a liquid crystal display panel and a backlight module, the liquid crystal display panel and the backlight module have multilayer optical elements, including setting a first multilayer film reflection sheet and a second multilayer film reflection sheet, And at least one optical film is arranged between the first multilayer film reflection sheet and the second multilayer film reflection sheet.

Description of drawings

FIG. 1 is a schematic structural view of a side-facing backlight module in the prior art;

FIG. 2 is a schematic diagram of a direct-lit backlight module in the prior art;

FIG. 3 is a schematic diagram of a backlight module applied to a liquid crystal display in the prior art;

4 is a schematic diagram of Embodiment 1 of a display backlight module of the present invention;

5 is a schematic diagram of Embodiment 2 of the display backlight module of the present invention;

Fig. 6 shows the process flow diagram of the display backlight module of the present invention;

FIG. 7A, FIG. 7B and FIG. 7C are schematic diagrams of structural embodiments of the multilayer reflective sheet of the present invention;

Figure 8 shows the manufacturing method of the embodiment of the multi-layer reflective sheet of the present invention; and

9A and 9B are schematic diagrams showing different stretching directions of different multi-layer reflective sheets in the backlight module of the present invention.

Description of main component symbols

current technology:

Liquid crystal display panel 101 Prism sheet 102

Diffusion film 103 Light guide plate 104

Light source 105 Reflector 106

Liquid crystal display panel 201 Prism sheet 202

Diffusion film 203 Light box 204

Light source 205 Reflective structure 206

Liquid crystal display device 30 LCD panel 301

Optical film 303 Brightness enhancement film 305

Light guide plate 307 Reflector plate 309

Light source 308

Invention embodiment:

Lateral backlight module 40 LCD panel 401

The first multi-layer reflective film 403 Diffusion film 405

Backlight diffusion film 406 Second multi-layer reflective film 407

Side light source 408 Light guide plate 409

Reflective sheet 410 Direct type backlight module 509

The first multilayer reflective sheet 503 The second multilayer reflective sheet 507

Liquid crystal display panel 501 First diffusion film 505

Light source 508 Second diffusion film 506

Reflective sheet 510 Surface structure 70, 62

Diffusion particles 708, 709 Substrates 711, 712

Polymer optical film 701, 703, 705, 707

Stretching directions 911, 912, 913, 914

Backlight module 901 The first multi-layer reflector 903

Diffusion film 905 Second multi-layer reflective sheet 907

LCD panel 909

Steps S601-S609 Backlight Module Manufacturing Method

Steps S801-S807 Manufacturing method of multilayer film reflection sheet

Detailed ways

The present invention proposes a display backlight module and its manufacturing method, which is different from the general way of providing optical elements such as light-enhancing films and diffusion films, in particular setting at least two layers of high molecular polymers with different refractive indices and superimposed on each other. The multi-layer reflective sheet composed of thin films, each multi-layer reflective sheet uses the principle of interference, can select the light to be reflected or penetrated with a specific wavelength range through design, and obtain a more uniform backlight.

As far as the material is concerned, the film of the above-mentioned high molecular polymer can be selected from the group or copolymer or mixture composed of the following high molecular substances: ethylene terephthalate (PolyethyleneTerephthalate, PET), polycarbonate (Polycarbonate , PC), tri-acetyl cellulose (Tri-acetyl Cellulose, TAC), polymethylmethacrylate particles (Polymethylmethacrylate, PMMA), MS plastic (Methylmethacrylate styrene), polypropylene (Polypropylene, PP), polystyrene (Polystyrene , PS), polymethyl methacrylate (PMMA), or cycloolefin copolymer (Cyclic Olefin Copolymer, COC), polyethylene naphthalate (Polyethylene Naphthalate, PEN), polyvinyl fluoride (Ethylene-Tetrafluoroethylene, ETFE), polylactic acid (Polylactide, PLA), coPEN, coPET, among which coPET and coPEN are copolymers mixed with part of PET and part of PEN in a certain proportion.

For an embodiment of the display backlight module, reference may be made to the schematic diagram of the embodiment shown in FIG. 4 , especially a side-facing backlight module applied to a liquid crystal display panel.

Shown in the figure is the backlight module arranged under the liquid crystal display panel 401, which includes a side-type backlight module 40, the optical elements therebetween may include multilayer optical films, at least a first multilayer film reflector 403 and Diffusion film 405, and a second multi-layer reflective film 407 may be provided on a light-emitting surface of the side-type backlight module 40, and in another embodiment, a backlight diffusion film 406 may be provided on the light-emitting surface . In particular, the newly added multi-layer film reflectors 403 and 407 are composed of multi-layer optical films with different refractive indices to produce the effects of diffusion and light enhancement.

There are at least two sets of multi-layer reflective sheets 403, 407 in the above-mentioned module. This is a structure in which multiple layers of thin films with different refractive indices are superimposed on each other. Please refer to the description of FIG. 7A to FIG. 7C of the present invention. One side of the side-type backlight module 40 is provided with a side-type light source 408, which is coupled to a light guide plate 409 to guide light into the backlight module. Sheet 410.

Among them, the light guide plate 409 effectively guides the light source 408 into the side-type backlight module 40 through the design of the internal and surface structures, and the light may go upward to the second multi-layer film reflector 407 during the traveling process, and the downward direction produced by refraction The light needs to be reflected by the reflective sheet 410 and then enter the backlight module 40 .

In particular, the first multilayer reflective sheet 403 is arranged at a position closer to the liquid crystal display panel 401, and the second multilayer reflective sheet 407 is arranged in the side-type backlight module 40, which can also be provided to assist diffusion Backlight diffuser film 406 for the light source. Here, the main purpose of the backlight diffusion film 406 is to provide support and provide a uniform light effect. The material of the backlight diffusion film 406 can generally be PC, PMMA, MS or PS, and the thickness is about 500um-6mm.

The diffusion film 406 can be a structural type or a diffusion film with diffusion particles added. The diffusion film 406 is attached to one side of the first multilayer film reflector 403, and the microstructure in the film is used to uniformly diffuse the side-facing backlight module 40 to produce The light is diffused by the microstructure in the film. Diffusion film 406 is combined with multi-layer film reflection sheet 407, which can produce better uniform effect

In the side-type backlight module 40, in addition to the backlight diffusion film 406 and the second multi-layer reflective sheet 407, there is also a reflective sheet 410, which defines a reflective cavity, and the light can generate multiple reflections and refractions in this cavity. and scattering, thereby increasing the optical path and achieving the purpose of homogenization.

The above-mentioned first multi-layer reflective sheet 403 and second multi-layer reflective sheet 407 will provide multiple light paths for multiple reflections and transmissions, because the structure is relatively thin and will not consume too much energy. In this way, the multi-layer reflective sheets 403 and 407 can not only produce the effect of light uniformity, but also have the effect of increasing light due to reflection and penetration of the multi-layer film. In particular, the principle of optical interference can be used to selectively reflect or transmit light with a specific wavelength range, to allow light in a specific wavelength range to pass through, or to reflect light in other wavelength ranges. The structure of the present invention can be matched with the design of the multi-layer film reflector to produce different designs, including the polarization effect produced by the extension process, or the difference in the polarization ratio of each P light and S light, or the design of the polarization direction. Made on demand.

In another embodiment, during the manufacturing process of the above-mentioned multilayer optical film, an ultraviolet reflective layer (not shown in the figure) that reflects ultraviolet (UV) can be specially added to reflect the excess ultraviolet rays generated by the light source, and can be used in Extruded or coated on other optical films. In this embodiment, unlike other methods of using materials that absorb ultraviolet rays, the ultraviolet reflective layer can reflect ultraviolet rays generated by light sources such as light-emitting diodes (LEDs), laser diodes (Laser diodes), and cold cathode tubes (CCFLs). and can be reused. When the light source is a semiconductor light source such as a laser diode or a light-emitting diode, the efficiency of the light-emitting diode can be improved by utilizing the function of several layers of optical films to effectively reflect ultraviolet rays. At present, the main semiconductor white light sources are mainly in the following three ways: 1. The white light emitting module is composed of red, blue and green three-color light-emitting diode grains, which has the advantages of high luminous efficiency and high color rendering, but at the same time, due to different color grain epitaxial materials Different, so that the voltage characteristics are also different. Therefore, the cost is high, the design of the control circuit is complicated, and the light mixing is not easy. 2. Proposed for Nichia to excite yellow YAG (Y3Al5O12:Ce; yttrium aluminum garnet) phosphors with blue light-emitting diodes to produce white light-emitting diodes, which is the mainstream method in the current market. The white light-emitting diode developed by Nichia Chemicals in Japan is filled with optical glue mixed with yellow YAG phosphor powder on the periphery of the blue light-emitting diode chip. The blue light emitted by the blue light-emitting diode chip has a wavelength of about 400-530nm. The light emitted by the LED chip excites the yellow phosphor to generate yellow light. But at the same time, part of the blue light will also be emitted, and this part of the blue light is combined with the yellow light emitted by the phosphor to form a white light with two wavelengths mixed with blue and yellow. However, this kind of white light emitting diode made of blue light emitting diode chips and yellow light phosphors has the following disadvantages: 1. Since blue light accounts for most of the luminous spectrum, there will be high color temperature and unevenness. Phenomenon. Based on the above reasons, it is necessary to increase the chance of interaction between the blue light and the yellow light phosphor to reduce the intensity of the blue light or increase the intensity of the yellow light. 2. Because the light-emitting wavelength of the blue light-emitting diode will change with the increase of temperature, it is difficult to control the color of the white light source. 3. Due to the weak red spectrum of light emission, the color rendition is poor.

Another way to obtain white light is to excite a certain proportion of blue, green, and red phosphors in the transparent optical adhesive with ultraviolet laser or ultraviolet light-emitting diodes. After excitation, white light mixed with three wavelengths can be obtained. Three-wavelength white light-emitting diodes have the advantage of high color rendering, but have the disadvantage of insufficient luminous efficiency. At present, white light LEDs are made of ultraviolet (UV) or blue light chips and phosphors. Their common disadvantages are insufficient luminance and difficulty in uniformity control. At present, the industry solves the problem of insufficient brightness of light-emitting diodes by increasing light transmittance and deriving or extracting more available light from the crystal grains. For example, using transparent conductive materials to increase the amount of light emitted by the crystal grains, changing the design of the epitaxy of the crystal grains or the electrode structure in order to extract more available luminescence.

In addition, when ultraviolet LEDs are used as the light source for exciting white light, the shorter the wavelength of ultraviolet rays, the greater the damage to human eyes. Therefore, it is necessary to block ultraviolet rays in the structure of white light LEDs and prevent ultraviolet rays from leaking out. The multilayer reflective sheet of the present invention is not provided with an absorber that absorbs ultraviolet light, but the function of increasing optical efficiency is achieved by arranging an ultraviolet reflective layer in the multilayer reflective sheet, especially for those excited by ultraviolet LEDs with high color rendering properties. The white light LED produced is more direct help. Applying this technology to the backlight of the LCD module can increase the LED luminous efficiency and improve the brightness of the backlight, and can reduce the sensitivity of the LED color to temperature changes and improve the color stability. .

For example, if the light source is a combination of blue light-emitting diode (LED) and yellow phosphor, the above-mentioned ultraviolet reflection layer can reflect the ultraviolet rays generated by the light source into the backlight module, and then reflect them out, not only can not affect other optical components , can also reuse to excite the LED phosphor, and can also increase the luminous efficiency of the LED. In the above-mentioned state of using ultraviolet excitation to generate white light, the part of the phosphor can be considered to add components that can be excited by ultraviolet light. That is to say, the mixed white light generally has two primary colors. ) contains at least two peaks, it may be excited by ultraviolet light other than the light of the original light-emitting diode to produce white light.

Other optical elements, such as optical films such as diffusion film 405 or 406, can then be combined on one surface of the first multilayer reflective sheet 403 or the second multilayer reflective sheet 407 to receive the Produces more uniform light. The diffuser film 405 or 406 mainly confuses the path of incoming light through its surface structure or particles, or built-in diffusion particles in the process, or contains bubbles in the interior, so as to produce a diffusion effect.

For another direct light source, reference may be made to the schematic diagram of Embodiment 2 of the display backlight module of the present invention shown in FIG. 5 .

The bottom of the liquid crystal display panel 501 displayed therein also includes a direct-type backlight module 509 and a multilayer optical film, including a first multilayer film reflective sheet 503 disposed close to the liquid crystal display panel 501, and the first multilayer film is laminated with the first multilayer film. The first diffusion film 505 of the film reflection sheet 503 may be provided with other diffusion films, such as another second diffusion film 506 as shown, according to the design.

In this example, the direct-lit backlight module 509 composed of the light source 508 and the reflective sheet 510 further includes a second multi-layer reflective sheet 507 . Wherein, the reflector 510 is coupled to the light source 508 and is mainly used to reflect the downgoing light generated by refraction of the light from the light source 508 .

The first multi-layer reflective sheet 503 is disposed between the direct type backlight module 509 and the liquid crystal display panel 501 . The second multi-layer film reflector 507 is arranged on the light-emitting surface of the direct-type backlight module 509, and defines a reflection cavity with the reflective element (reflector 510) in the direct-type backlight module 509, where light can Multiple reflections, refractions and scattering are generated in the cavity, thereby increasing the optical path and achieving the purpose of homogenization.

Like the multi-layer multi-layer film reflection sheet applied in the backlight module of the side light source, the above-mentioned first multi-layer film reflection sheet 503 and the second multi-layer film reflection sheet 507 will provide multiple reflection and transmission The light path can produce the effect of light uniformity, and the effect of adding light is caused by the reflection and penetration of the multi-layer film. And the optical interference principle can be used to selectively reflect or penetrate the light with a specific wavelength range, so that the light of a specific wavelength range can pass through, or the light of other wavelength ranges can be reflected.

In this example, one or more diffusion films can be selected, such as the first diffusion film 505 or the second diffusion film 506, or can be used in combination, and the diffusion film will be attached to one side of the first multilayer film reflection sheet 503 , using the microstructure in the film to evenly diffuse the light generated by the direct-lit backlight module

It is worth mentioning that the light source of the direct-lit backlight module can be an array of light-emitting diodes, and the preferred embodiment is composed of multiple groups of light-emitting elements with red, green, and blue colors, or other combinations of light-emitting diodes. LED array.

Refer to FIG. 6 for the process flow chart of the above-mentioned display backlight module of the present invention.

The steps start as S601, setting up a liquid crystal display panel, and step S603 setting up a backlight module. The backlight module includes two types of backlight modules: side-light or direct-light.

Next, as in step S605 , a first multi-layer reflective sheet is provided, and the first multi-layer reflective sheet composed of multiple layers of polymer films with different refractive indices laminated to each other is bonded to the liquid crystal display panel.

Next, an optical film is provided, especially between the first multi-layer reflective sheet and the underlying structure, which can be a diffusion film for uniformly dispersing the light source, a brightness enhancement film or other types of optical films with specific functions (step S607 ).

On the light emitting surface of the backlight module, i.e., the upper surface in the figure, a second multilayer reflective sheet is provided (step S609), and the interference and multiple reflections generated by the multilayer film structure are used to form a uniform backlight, and the required penetration can be selected. or reflected wavelengths of light.

The above process is applied to a display backlight module with a side-type or a direct-type light source. In particular, the second multi-layer reflective sheet formed in the above step S609 can be integrated into the side-type backlight module, which is also a part of the backlight module, and can also be supplemented with other optical films, as shown in Figure 4 Backlight diffusion film (406); and in the display backlight module of the direct light source, the first and second multilayer film reflectors, or more layers of multilayer film reflectors will be arranged on the backlight module and the liquid crystal display panel together between.

The structure of the above-mentioned first and second multilayer film reflectors is that multiple layers of high and low refractive index are stacked sequentially. The schematic diagram shows the stacked polymer optical films 701, 703, 705, 707 as shown in Fig. 7A. The number of stacked layers of multilayer polymer optical films inside the upper multilayer film reflector can range from dozens to hundreds of layers, and the figure only shows the multilayer structure, not the structure of hundreds of layers. The multi-layer film structure forms an interference condition, which allows the light to be emitted after multiple reflections, which has the effect of homogenizing the light source; it can also reflect the reflected light again, which has the effect of increasing light. The optical characteristics can be changed by the thickness of the overall multi-layer film reflector, the degree of extension in the material and the process, and can be designed according to actual needs. The characteristics of the multi-layer reflective sheet can be adjusted according to requirements, especially after the uniaxial or biaxial stretching process, the transmittance of light with a spectrum of 400nm-700nm can be between 30% and 90%.

When the light source is composed of multiple colors, such as using a light source composed of red, green and blue multi-color LEDs, the phenomenon of uneven color mixing often occurs, which is called moiré (MURA). Or the biaxial stretching process can effectively adjust the ratio of P and S polarization states, and only use biaxial stretching to adjust the light without polarization state. When the light is repeatedly reflected in the multilayer film reflector and the reflector and the optical module The light path length of each light source will be effectively lengthened, the luminance uniformity and color uniformity of the backlight module will be increased, and the MURA phenomenon will be reduced.

In addition to the above-mentioned multilayer film structure, the multilayer reflective sheet also includes an ultraviolet reflective layer made by a co-extrusion process or a coating process, in which light-transmitting plastic particles that reflect ultraviolet rays can be added to make the multilayer film reflective sheet. The ultraviolet reflection layer is formed in the multi-layer film reflection sheet. Another process may also include sputtering or evaporating an anti-ultraviolet film on the multi-layer reflective sheet or plating it on a base material and then laminating it with the multi-layer reflective sheet.

In manufacturing, in particular, when the multilayer reflective sheet is formed, it can be stretched in the uniaxial or biaxial direction, including machine or artificial stretching, so that the molecular chain and alignment structure of the internal polymer can be changed. Change its physical properties, especially the properties of polarized light.

For example, after using uniaxial stretching (generally, the uniaxial stretching ratio can reach 1.5 to 6 times, or even a larger ratio, depending on the demand and the film material), where the film material includes Polyethylene Terephthalate (Polyethylene Terephthalate, PET), polycarbonate (Polycarbonate, PC), tri-acetyl cellulose (Tri-acetyl Cellulose, TAC), polymethylmethacrylate particles (Polymethylmethacrylate, PMMA), MS plastic (Methylmethacrylate styrene), polypropylene (Polypropylene, PP), polystyrene (Polystyrene, PS), polymethyl methacrylate (PMMA), or cycloolefin copolymer (Cyclic Olefin Copolymer, COC), polyethylene naphthalate (Polyethylene Naphthalate, PEN), Polyethylene-Tetrafluoroethylene (ETFE), polylactic acid (Polylactide, PLA). The optical element after the uniaxial stretching process can have a polarization effect in a specific direction, and the wavelength range of the polarized light can be adjusted accordingly.

If it is a biaxial stretching process (biaxial stretching, the two-axis stretching magnification can be different, or it can be sequential biaxial or simultaneous biaxial stretching), in addition to adjusting the wavelength range, it can better control the intensity of the light passing through the multi-layer film reflector. The ratio of P polarization to S polarization. And it can cooperate with the characteristics of other optical films (such as the above-mentioned diffusion film and brightness enhancement film) to make the overall backlight module more uniform, diffuse, eliminate chromatic aberration, adjust polarization state, adjust reflectivity, reduce moire (MURA) and can use The principle of interference modulates light in a specific wavelength range.

Embodiments Please refer to FIG. 7B and FIG. 7C , which are schematic diagrams of structural embodiments of the multi-layer reflective sheet of the present invention.

The multilayer reflective sheet shown in FIG. 7B is formed by extrusion or coating on a surface (such as the upper surface or the lower surface in the figure) outside the structural polymer optical films 701, 703, 705, and 707. Surface structure 70. The surface structure 70 can generally be composed of microstructures with a length or width of about 5 um to 100 um, and the shape of the microstructures forming the surface structure 70 is usually spherical, hemispherical, prism or pyramid. etc., or consist of various structures that can diffuse light. The distribution of the microstructures can be uniform or chaotic and non-uniform, so as to avoid overlapping with other components to produce moiré patterns. The function of the surface structure 70 is to confuse the optical path of the emitted light, increase the optical path, and increase the uniformity of the light. In addition, diffusion particles 708 can also be added in the process of making the surface structure 70 to increase the diffusion ability of light. The diffusion particles 708 can be selected from polymers such as acrylic, silicon dioxide, or titanium dioxide. The difference in rate causes refraction and scattering of light, and the shape of the particles can also be elongated or close to ellipse or round, and the diffusion particles 708 can be mixed inside the optical glue used for coating.

The two sides of the polymer optical film 701, 703, 705, and 707 of the multilayer film reflector shown in FIG. The surface structures 70 and 62 are formed by the coating process on the upper and lower sides, and the diffusion particles 708 and 709 can be formed at the same time, thereby increasing the diffusion ability of the multi-layer film reflection sheet. In this example, the upper surface structure 70 can be bonded (by lamination process, lamination) to the diffusion film or other optical films in the display backlight module of the present invention to form an integral optical element, such as reflection in each multilayer film A first diffusion film is pasted on the upper surface of the sheet, a second diffusion film is pasted on the lower surface, and there may be a plurality of diffusion particles in optical elements such as the first diffusion film and the second diffusion film.

The above-mentioned substrates 711 and 712 for forming the surface structure are used as plastics supporting the structure of the multilayer film reflector, which can be polycarbonate (PC), polypropylene (Polypropylene, PP), PS plastic (Polystyrene, PS), polypropylene Methyl methacrylate (PMMA), MS plastic (Methylmethacrylate styrene), acrylic butadiene styrene (ABS), polyethylene terephthalate (PET), polyacetal plastic (Polyoxymethylene, POM), Nylon (Nylon), polyethylene naphthalate (Polyethylene Naphthalate, PEN), or CoPEN or CoPET (Ethylene-Tetrafluoroethylene, ETFE), polylactic acid (Polylactide, PLA), etc. materials, but not limited to the above.

Fig. 8 shows the manufacturing method of the embodiment of the multi-layer reflective sheet of the present invention.

Such as step S801, using co-extrusion process (co-extrusion) to make a multi-layer film reflective sheet formed by multi-layer polymer film, wherein one or more extruders can be used to transport polymer materials of different materials After entering the interior of a co-extrusion die, after extrusion, it can go through the steps of cooling and shaping, drawing and cutting, such as step S803, to form a multi-layer film reflection sheet.

In the meantime, an online uniaxial stretching process can be adopted after extrusion and before shaping, or a uniaxial stretching process can be performed after offline (offline) film wrapping to form an optical element with a polarizing effect; either online or offline Executing a biaxial stretching process, so as to control the ratio of P polarization and S polarization of the light passing through the multilayer film reflection sheet, or form a multilayer film reflection sheet without polarization characteristics (step S805), the extension process changes the multilayer film The physical properties of the reflector produce an optical element that reflects light for a specific wavelength range, while changing the polarization effect according to the extension ratio of uniaxial or biaxial. Finally, a surface structure can be formed on the multi-layer reflective sheet (step S807).

9A and 9B are schematic diagrams showing different stretching directions of different multi-layer reflective sheets in the backlight module of the present invention.

When the multi-layer reflective sheet is stretched, the molecules in the material or other additional particles will produce a more regular stretching direction during the stretching process, thereby resulting in an extended axis (stretching axis) is significantly different from the optical rotation perpendicular to this axis, producing a polarized effect.

FIG. 9A shows a schematic diagram of a set of backlight modules, including a backlight module 901 , a first multilayer reflective sheet 903 , a diffusion film 905 , a second multilayer reflective sheet 907 and a liquid crystal display panel 909 . According to this embodiment, the stretching process shown in FIG. 8 is introduced in the manufacturing process of the first multilayer reflective sheet 903 and the second multilayer reflective sheet 907. After uniaxial stretching or biaxial stretching with different ratios, The molecular arrangement of the first multilayer film reflection sheet 903 and the second multilayer film reflection sheet 907 have different directions, which are respectively the stretching directions 911 and 912 in the figure, so as to extend the design of the process, so that the two multilayer film The reflection sheets 903, 907 have different characteristics, and produce different effects when the light passes through the backlight module.

FIG. 9B shows that the above-mentioned first multilayer reflective sheet 903 and second multilayer reflective sheet 907 are designed to be located on upper and lower layers, and have different stretching directions 913 , 914 , and are not even vertically designed. In this way, the first multilayer reflective sheet 903 and the second multilayer reflective sheet 907 are designed to have different optical characteristics, such as polarization effects in different directions after being stretched, and the polarization direction can be asymmetrical, or rotated by an angle, and It can have different polarization ratios for different polarized light (P light, S light), and even produce different penetrating light effects through different thickness designs. The optical films of different layers in the figure have different stretching directions 913, 914, and have an included angle.

Based on the above content, in addition to the diffusion film with diffusion effect, the display backlight module proposed by the present invention is specially provided with two or more multi-layer film reflection sheets formed by laminating multiple layers of different refractive index films. properties:

1. The first multilayer reflective sheet and the second multilayer reflective sheet are set in the backlight module of the liquid crystal display at the same time, and the interference principle between the multilayer thin films with different refractive indices in the multilayer reflective sheet is used to set the desired Reflect or transmit light with a specific wavelength range, and can obtain a more uniform backlight due to the increased optical path and multiple reflections;

2. A reflective cavity is defined between the first multi-layer film reflector and the reflector (reflector) in the backlight module. In this cavity, the light will produce multiple reflections, refraction, scattering and other physical phenomena, thereby increasing the confusion. The path of light achieves the function of homogenization;

3. The first multilayer reflector and the second multilayer reflector are designed to be located on the upper and lower layers, and their polarization directions can be asymmetrical or rotated by an angle;

4. The transmittance of the multilayer film reflector can be changed by the material, thickness and extension multiple conditions of the multilayer film;

5. By controlling the reflectivity and transmittance, the MURA state of the light source can be adjusted after being used with the diffusion film, which can assist the diffusion film and the light guide plate to increase the uniformity function, so that the display backlight module can produce a more uniform light;

6. The physical properties of the multilayer reflective film can be adjusted by the uniaxial stretching process, so that the light in different polarization states has different reflectivity and refractive index. By adjusting the reflectivity and refractive index of the multilayer reflective film penetration rate;

7. At least two groups of multi-layer film reflectors are matched with each other, which can be designed to produce effects of different optical characteristics, including the generation of light with a specific polarization state, P light and S light with different polarization ratios;

8. The biaxially stretched multi-layer film reflector can be designed as a film without polarizing effect, but can be designed as a film with reflection and filter effect;

9. A layer of ultraviolet reflective layer can be selectively made in the multilayer film reflector to reflect the excess ultraviolet rays generated by the light source, so that they can be reused, and stimulate specific components in the LED phosphor to increase the luminous efficiency.

The above description is only a preferred feasible embodiment of the present invention, and does not limit the patent scope of the present invention. Therefore, all equivalent structural changes made by using the description of the present invention and the contents of the accompanying drawings are all included in the scope of the present invention in the same way. Inside.

Claims (38)

1. A display backlight module, applied in a liquid crystal display device, comprising: One-sided backlight module, including: One side light source; a light guide plate coupled to the side light source; A reflective sheet, arranged on one side of the light guide plate, used to reflect the down-going light entering the light guide plate among the light rays of the side light source; A second multi-layer film reflection sheet is arranged on a light-emitting surface of the side-type backlight module, and is composed of multiple layers of polymer films with different refractive indices and superimposed on each other, which is designed using the principle of interference Reflecting or penetrating light with a specific wavelength range; a reflection cavity is defined between the second multi-layer reflective sheet and the reflective sheet, and the light generates multiple reflections, refraction and scattering in the reflection cavity; and A first multi-layer film reflection sheet is arranged between the side-type backlight module and a liquid crystal display panel, and is composed of multiple layers of polymer films with different refractive indices and superimposed on each other. The principle design reflects or transmits light with a specific wavelength range; and A diffusion film is attached to one side of the first multi-layer film reflection sheet, and the light generated by the side-type backlight module is evenly diffused by using the microstructure in the film. 2 . The display backlight module according to claim 1 , wherein a surface structure is coated or extruded on a surface of the first multilayer reflective sheet or the second multilayer reflective sheet. 3. The display backlight module according to claim 2, wherein the surface structure of the first multilayer reflective sheet or the second multilayer reflective sheet further comprises a plurality of diffusion particles. 4. The display backlight module according to claim 2, wherein a diffusion film is attached to the surface of the first multilayer reflective sheet or the second multilayer reflective sheet. 5. The display backlight module according to claim 4, wherein the diffusion film on the surface has a plurality of diffusion particles. 6 . The display backlight module according to claim 1 , wherein the multilayer structure of the first multilayer reflective sheet or the second multilayer reflective sheet further includes an ultraviolet reflective layer that reflects ultraviolet rays. 7. The display backlight module according to claim 1, wherein the first multi-layer reflective sheet or the second multi-layer reflective sheet is manufactured by a uniaxial stretching process. 8. The display backlight module according to claim 7, wherein, after the first multi-layer reflective sheet or the second multi-layer reflective sheet undergoes the uniaxial stretching process, the average value in the spectrum of 400nm to 700nm The penetration rate is between 30% and 90%. 9. The display backlight module according to claim 1, wherein the first multi-layer reflective sheet or the second multi-layer reflective sheet is manufactured by a biaxial stretching process. 10. The display backlight module according to claim 9, wherein, after the first multi-layer reflective sheet or the second multi-layer reflective sheet undergoes the biaxial stretching process, in the spectrum of 400nm-700nm The average penetration rate is between 30% and 90%. 11. The display backlight module according to claim 1, wherein the first multilayer reflective sheet or the second multilayer reflective sheet is made by a biaxial stretching process, and the multilayer reflective sheet Polarizing properties. 12. The display backlight module according to claim 1, wherein the first multilayer reflective sheet or the second multilayer reflective sheet is made by a biaxial stretching process, and the multilayer reflective sheet Does not have polarizing properties. 13. A display backlight module, applied in a liquid crystal display device, comprising: All the way down type backlight module, including: a light source; A reflector, coupled to the light source, for reflecting a down-going light generated by refraction of light from the light source; A second multi-layer film reflection sheet is arranged on a light-emitting surface of the direct-lit backlight module, and is composed of multiple layers of high-molecular polymer films with different refractive indices and superimposed on each other, wherein the reflection is designed by using the interference principle Or penetrate light with a specific wavelength range; a reflective cavity is defined between the multilayer reflective sheet and the reflective plate, and the light generates multiple reflections, refraction and scattering in the reflective cavity; and A first multi-layer film reflection sheet is arranged between the direct-type backlight module and a liquid crystal display panel, and is composed of multiple polymer films with different refractive indices and superimposed on each other, wherein the principle of interference is used Designed to reflect or transmit light with specific wavelength ranges; and A diffusion film is attached to one side of the first multi-layer film reflection sheet, and the light generated by the direct-type backlight module is evenly diffused by using the microstructure in the film. 14. The display backlight module according to claim 13, wherein the light source of the direct type backlight module is a light emitting diode array. 15. The display backlight module according to claim 14, wherein the light-emitting diode array is composed of multiple groups of red, green and blue light-emitting diodes, laser diodes, or blue light-excited phosphor powder or ultraviolet light-excited multiple light-emitting diodes. Composed of light-emitting elements of light-emitting diodes with colored phosphors. 16 . The display backlight module according to claim 13 , wherein a surface structure is coated or extruded on a surface of the first multilayer reflective sheet or the second multilayer reflective sheet. 17. The display backlight module according to claim 16, wherein the surface structure of the first multilayer reflective sheet or the second multilayer reflective sheet further comprises a plurality of diffusion particles. 18. The display backlight module according to claim 16, wherein a diffusion film is attached to the surface of the first multilayer reflective sheet or the second multilayer reflective sheet. 19. The display backlight module of claim 18, wherein the diffusion film on the surface has a plurality of diffusion particles. 20. The display backlight module according to claim 13, wherein the multi-layer structure of the first multi-layer reflective sheet or the second multi-layer reflective sheet further comprises an ultraviolet reflective layer that reflects ultraviolet rays. 21. The display backlight module according to claim 13, wherein the first multilayer reflective sheet or the second multilayer reflective sheet is manufactured by a uniaxial stretching process. 22. The display backlight module according to claim 21, wherein, after the first multi-layer reflective sheet or the second multi-layer reflective sheet undergoes the uniaxial stretching process, it has a spectrum of 400nm-700nm The average penetration rate is between 30% and 90%. 23. The display backlight module according to claim 13, wherein the first multi-layer reflective sheet or the second multi-layer reflective sheet is manufactured by a biaxial stretching process. 24. The display backlight module according to claim 23, wherein, after the first multi-layer reflective sheet or the second multi-layer reflective sheet undergoes the biaxial stretching process, it has a spectrum between 400nm and The average transmittance at 700nm is between 30% and 90%. 25. The display backlight module according to claim 13, wherein the first multilayer reflective sheet or the second multilayer reflective sheet is made by a biaxial stretching process, and the multilayer reflective sheet Polarizing properties. 26. The display backlight module according to claim 13, wherein the first multilayer reflective sheet or the second multilayer reflective sheet is made by a biaxial stretching process, and the multilayer reflective sheet Does not have polarizing properties. 27. A method of manufacturing a display backlight module, comprising: A liquid crystal display panel is provided; A backlight module is provided with a light source and a reflective element; A first multi-layer reflective sheet is provided to be bonded to the liquid crystal display panel. The first multi-layer reflective sheet is composed of multiple polymer films with different refractive indices and superimposed on each other. Using interference The principle design reflects or penetrates light with a specific wavelength range; A second multi-layer reflective sheet is provided to be bonded to the backlight module. The second multi-layer reflective sheet is composed of multiple polymer films with different refractive indices and laminated with each other. Using interference The principle design reflects or penetrates light with a specific wavelength range; and, a reflective cavity is defined between the second multilayer film reflective sheet and the reflective element in the backlight module, and the light is in the reflective cavity multiple reflections, refractions and scattering within the cavity; and An optical film is arranged between the first multilayer reflective sheet and the second multilayer reflective sheet. 28. The manufacturing method of a display backlight module according to claim 27, wherein the first multi-layer reflective sheet and the second multi-layer reflective sheet are produced by a co-extrusion process. 29. The manufacturing method of the display backlight module according to claim 28, wherein the first multi-layer reflective sheet or the second multi-layer reflective sheet also undergoes a uniaxial stretching process to form a polarizing effect Optical element. 30. The method for manufacturing a display backlight module according to claim 29, wherein the first multilayer reflective sheet or the second multilayer reflective sheet produced by the uniaxial stretching process has a spectrum between 400nm and The average transmittance at 700nm is between 30% and 90%. 31. The manufacturing method of a display backlight module according to claim 28, wherein the first multilayer reflective sheet and the second multilayer reflective sheet are further subjected to a biaxial stretching process, so as to control the The ratio of P polarization and S polarization of the light of the first multilayer film reflection sheet or the second multilayer film reflection sheet. 32. The manufacturing method of the display backlight module according to claim 31, wherein, the first multi-layer reflective sheet or the second multi-layer reflective sheet produced by the biaxial stretching process has a spectrum between 400nm and The average transmittance at 700nm is between 30% and 90%. 33. The manufacturing method of a display backlight module according to claim 27, wherein the backlight module is an edge-lit backlight module. 34. The method for manufacturing a display backlight module according to claim 27, wherein the backlight module is a direct-type backlight module. 35. The manufacturing method of a display backlight module according to claim 34, wherein the light source of the direct-lit backlight module is an array of light emitting diodes, and the array of light emitting diodes has three colors of red, green and blue in multiple groups, Or other types of light-emitting diodes. 36. The method for manufacturing a display backlight module according to claim 27, wherein a coating process is used to form a surface on one surface of the first multilayer reflective sheet or the second multilayer reflective sheet structure. 37. The method of manufacturing a display backlight module according to claim 36, wherein the surface structure has a plurality of diffusion particles. 38. The manufacturing method of the display backlight module according to claim 27, wherein, the multilayer structure of the multilayer film reflection sheet also includes an ultraviolet ray made by a co-extrusion, coating, sputtering or evaporation process. reflective layer.

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