Reflective sheet and backlight module for preventing warping and wrinkling

Abstract

The present invention provides a reflective sheet for preventing warping and wrinkling, comprising a silver-plated base film, a first adhesive layer, an aluminum-plated base film, a second adhesive layer and a PET film in contact with each other in sequence; the aluminum-plated base film comprises one or two layers of PET aluminum-plated film; the aluminum layer in each layer of the PET aluminum-plated film is closer to the silver-plated base film; when the aluminum-plated base film is a layer of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film is 100-1000nm; when the aluminum-plated base film is two layers of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film close to the silver-plated base film is 100-800nm, and the thickness of the aluminum layer in the PET aluminum-plated film close to the PET film is 100-600nm. The present invention avoids the wrinkling and warping deformation of the material caused by the contact between the PET reflective sheet and the light guide plate LED; and also solves the problem of silver film warping caused by the large amount of heat absorbed by the aluminum film. The present invention also provides a backlight module.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid crystal display backlight modules, and in particular relates to a reflective sheet and a backlight module capable of preventing warping and wrinkling. Background Art

[0002] LCD products are non-active light-emitting electronic devices that do not have light-emitting properties. They must rely on the emission of light sources in the backlight module to obtain display performance. Therefore, the brightness of the LCD is determined by its backlight module. It can be seen that the quality of the backlight determines important parameters such as the brightness, uniformity of the emitted light, and color gradation of the LCD screen, and to a large extent determines the luminous effect of the LCD screen.

[0003] The backlight module includes a lighting source, a reflector, a light guide plate, a diffuser, a brightness enhancement film (prism) and a frame. The backlight modules used by LCDs can be divided into two categories: edge-lit backlight modules and direct-lit backlight modules. Mobile phones, laptops and monitors (15 inches) mainly use edge-lit backlight modules, while LCD TVs mostly use direct-lit backlight module light sources. The backlight module light source is mainly a light-emitting diode (LED) light source as the backlight source of LCDs.

[0004] The existing commercially available reflective sheets are composed of two PET films bonded together, generally composed of a silver-plated reflective sheet and a black or white reflective sheet, or an aluminum-plated film. The silver reflective sheet has a strong reflective property and is currently used in LCD backlight modules. However, it is affected by the LED light source. In addition to the existing ambient temperature, it is also affected by the LED heat source, causing deformation or bulges on the surface of the material on the white film, black film or aluminum-plated film, or a rough surface, resulting in uneven reflected light, dark or bright light sources.

[0005] In the prior art, the problem of silver film warping has never been overcome, which further affects the reflective performance of the reflective sheet. Summary of the invention

[0006] The purpose of the present invention is to provide a reflector and backlight module that can prevent warping and wrinkling. The reflector in the present invention uses the thermal conductivity and color dispersion properties of aluminum to disperse the extra heat generated by the LED, which can simultaneously solve the problems of material surface wrinkles and silver film warping.

[0007] The present invention provides a reflective sheet for preventing warping and wrinkling, comprising a silver-plated base film, a first adhesive layer, an aluminum-plated base film, a second adhesive layer and a PET film which are in contact with each other in sequence;

[0008] The aluminum-plated base film includes one or two layers of PET aluminum-plated film; the aluminum layer in each layer of the PET aluminum-plated film is closer to the silver-plated base film;

[0009] When the aluminum-plated base film is a layer of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film is 100 to 1000 nm;

[0010] When the aluminum-plated base film is a two-layer PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film close to the silver-plated base film is 100-800nm, and the thickness of the aluminum layer in the PET aluminum-plated film close to the PET film is 100-600nm.

[0011] Preferably, the silver-plated base film comprises a silver-plated PET layer and a silver layer composited on the surface of the PET base film;

[0012] The thickness of the silver-plated PET layer in the silver-plated base film is 12 to 50 μm; the thickness of the silver layer in the silver-plated base film is 60 to 200 nm.

[0013] Preferably, when the aluminized base film is a layer of PET aluminized film, the thickness of the aluminized PET layer in the PET aluminized film is 12 to 25 μm.

[0014] Preferably, when the aluminized base film is two layers of PET aluminized film, the two layers of PET aluminized film are connected by an adhesive layer.

[0015] Preferably, the aluminum-coated base film is a two-layer PET aluminum-coated film, the thickness of the aluminum-coated PET layer in the PET aluminum-coated film close to the silver-coated base film is 10 to 25 nm, and the thickness of the aluminum-coated PET layer in the PET aluminum-coated film close to the PET film is 10 to 25 nm.

[0016] Preferably, the thickness of the PET film is 12-50 μm; the PET film is a transparent PET film, a white PET film or a black PET film.

[0017] Preferably, the aluminum-plated base film is a layer of PET aluminum-plated film, and the total thickness of the reflective sheet is 42 to 82 μm;

[0018] The aluminized base film is a two-layer PET aluminized film, and the total thickness of the reflective sheet is 70-160 μm.

[0019] The present invention provides a backlight module, comprising the above-mentioned reflective sheet for preventing warping and wrinkling.

[0020] The invention provides a reflective sheet for preventing warping and wrinkling, comprising a silver-plated base film, a first adhesive layer, an aluminum-plated base film, a second adhesive layer and a PET film which are in contact with each other in sequence; the aluminum-plated base film comprises one or two layers of PET aluminum-plated films; the aluminum layer in each layer of the PET aluminum-plated films is closer to the silver-plated base film; when the aluminum-plated base film is one layer of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film is 100-1000nm; when the aluminum-plated base film is two layers of PET aluminum-plated films, the thickness of the aluminum layer in the PET aluminum-plated film close to the silver-plated base film is 100-800nm, and the thickness of the aluminum layer in the PET aluminum-plated film close to the PET film is 100-600nm. The present invention adopts a multi-layer aluminum film design so that the reflector is evenly heated under the influence of the heat environment and the heat emitted by the LED, etc., thereby avoiding the reflector from being affected by the LED light and causing wrinkles and deformation of the material; at the same time, the present invention also arranges an uncoated PET layer on the top of the reflector. Under long-term heating or high-temperature environment, the entire film layer of the reflector will warp toward the uncoated PET layer, which can balance the bulge of the silver film caused by heating, and solves the problem of silver film warping caused by the large amount of heat absorbed by the aluminum film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 It is a schematic structural diagram of a reflective sheet for preventing warping and wrinkling when the aluminum-plated base film is a layer of PET aluminum-plated film in the present invention;

[0023] Among them, 1 is a silver-plated base film, 1-1 is a silver-plated PET layer, 1-2 is a silver layer, 2 is a first bonding layer, 3 is an aluminum-plated base film, 3-1 is an aluminum layer, 3-2 is an aluminum-plated PET layer, 4 is a second bonding layer, and 5 is a PET film;

[0024] Figure 2 It is a schematic structural diagram of a reflective sheet for preventing warping and wrinkling when the aluminum-plated base film is a two-layer PET aluminum-plated film in the present invention;

[0025] Among them, 1 is a silver-plated base film, 1-1 is a silver-plated PET layer, 1-2 is a silver layer, 2 is a first bonding layer, 3 is an aluminum-plated base film B, 3-1 is an aluminum layer B, 3-2 is an aluminum-plated PET layer B, 4 is a second bonding layer, 5 is an aluminum-plated base film A, 5-1 is an aluminum layer A, 5-2 is an aluminum-plated PET layer A, 6 is a third bonding layer, and 7 is a PET film. DETAILED DESCRIPTION

[0026] The object of the present invention is to provide a reflective sheet for preventing warping and wrinkling, comprising a silver-plated base film, a first adhesive layer, an aluminum-plated base film, a second adhesive layer and a PET film which are in contact with each other in sequence;

[0027] The aluminum-plated base film includes one or two layers of PET aluminum-plated film; the aluminum layer in each layer of the PET aluminum-plated film is closer to the silver-plated base film;

[0028] When the aluminum-plated base film is a layer of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film is 100 to 1000 nm;

[0029] When the aluminum-plated base film is a two-layer PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film close to the silver-plated base film is 100-800nm, and the thickness of the aluminum layer in the PET aluminum-plated film close to the PET film is 100-600nm.

[0030] In the present invention, the reflective sheet for preventing warping and wrinkles can be divided into two structures according to the demand for the thickness of the reflective sheet in actual production. One is that the aluminum-plated base film is two layers of PET aluminum-plated film, and the other is that the aluminum-plated base film is a single layer of PET aluminum-plated film. When a thinner reflective sheet is needed, the structure in which the aluminum-plated base film is a single layer of PET aluminum-plated film can be selected.

[0031] 1) When the aluminized base film is a layer of PET aluminized film,

[0032] The reflective sheet for preventing warping and wrinkles includes a silver-plated base film, a first adhesive layer, a PET aluminum-plated film, a second adhesive layer and a PET film that are in contact with each other in sequence; specifically, the reflective sheet for preventing warping and wrinkles includes a silver-plated PET layer, a silver layer, a first adhesive layer, an aluminum layer, an aluminum-plated PET layer, a second adhesive layer and a PET film that are in contact with each other in sequence.

[0033] In the present invention, the thickness of the silver-plated PET layer is preferably 12 to 50 μm, more preferably 20 to 40 μm, and most preferably 25 to 30 μm. Specifically, in the embodiments of the present invention, it can be 12 μm or 25 μm.

[0034] In the present invention, the thickness of the silver layer is preferably 60 to 200 nm, more preferably 80 to 150 nm, and most preferably 100 to 120 nm. Specifically, in an embodiment of the present invention, it can be 60 nm, 100 nm, 120 nm or 200 nm.

[0035] In the present invention, the first adhesive layer is preferably a polyurethane adhesive layer, and the thickness of the first adhesive layer is preferably 3-4 μm.

[0036] In the present invention, when the aluminum-plated base film is a layer of PET aluminum-plated film, the thickness of the aluminum layer should be increased accordingly, preferably 100-1000nm, more preferably 200-800nm, most preferably 400-600nm. Specifically, in the embodiments of the present invention, it can be 100nm, 400nm, 600nm or 1000nm.

[0037] In the present invention, the thickness of the aluminum-plated PET layer is preferably 12 to 25 μm, more preferably 15 to 20 μm. Specifically, in the embodiments of the present invention, it can be 12 μm or 25 μm.

[0038] In the present invention, the second adhesive layer is preferably a polyurethane adhesive layer, and the thickness of the second adhesive layer is preferably 3-4 μm.

[0039] In the present invention, the PET film may be a transparent PET film, a white PET film or a black PET film, and the thickness of the PET film is preferably 12 to 50 μm, more preferably 12 to 40 μm, and specifically, in an embodiment of the present invention, may be 12 μm or 25 μm.

[0040] When the aluminum-plated base film is a layer of PET aluminum-plated film, the total thickness of the reflective sheet is preferably 42 to 82 μm, more preferably 55 to 69 μm. Specifically, in the embodiments of the present invention, it can be 42 μm, 55 μm, 69 μm or 82 μm.

[0041] 2) When the aluminized base film is a two-layer PET aluminized film,

[0042] The reflective sheet for preventing warping and wrinkles includes a silver-plated base film, a first adhesive layer, an aluminum-plated base film B, a second adhesive layer, an aluminum-plated base film A, a third adhesive layer and a PET film that are in contact with each other in sequence. Specifically, the reflective sheet for preventing warping and wrinkles includes a silver-plated PET layer, a silver layer, a first adhesive layer, an aluminum layer B, an aluminum-plated PET layer B, a second adhesive layer, an aluminum layer A, an aluminum-plated PET layer A, a third adhesive layer and a PET film that are in contact with each other in sequence.

[0043] In the present invention, the thickness of the silver-plated PET layer is preferably 20-50 μm, more preferably 25-40 μm, most preferably 25-30 μm. Specifically, in the embodiments of the present invention, it can be 20 μm, 25 μm or 50 μm.

[0044] In the present invention, the thickness of the silver layer is preferably 60 to 200 nm, more preferably 80 to 150 nm, and most preferably 100 to 120 nm. Specifically, in an embodiment of the present invention, it can be 60 nm, 100 nm, 120 nm or 200 nm.

[0045] In the present invention, the first adhesive layer is preferably a polyurethane adhesive layer, and the thickness of the first adhesive layer is preferably 3-4 μm.

[0046] In the present invention, the thickness of the aluminum layer B is preferably 100-800 nm, more preferably 200-700 nm, most preferably 300-450 nm. Specifically, in the embodiments of the present invention, it can be 100 nm, 450 nm or 800 nm.

[0047] In the present invention, the thickness of the aluminum-plated PET layer B is preferably 10 to 25 μm, more preferably 12 to 20 μm. Specifically, in the embodiments of the present invention, it can be 10 μm, 12 μm or 25 μm.

[0048] In the present invention, the second adhesive layer is preferably a polyurethane adhesive layer, and the thickness of the second adhesive layer is preferably 3 to 4 μm.

[0049] In the present invention, the thickness of the aluminum layer A is preferably 100-600 nm, more preferably 200-500 nm, most preferably 300-400 nm. Specifically, in the embodiments of the present invention, it can be 100 nm, 300 nm or 600 nm.

[0050] In the present invention, the thickness of the aluminum-plated PET layer A is preferably 10 to 25 μm, more preferably 12 to 20 μm. Specifically, in the embodiments of the present invention, it can be 10 μm, 12 μm or 25 μm.

[0051] In the present invention, the third adhesive layer is preferably a polyurethane adhesive layer, and the thickness of the third adhesive layer is preferably 3-4 μm.

[0052] In the present invention, the PET film can be a transparent PET film, a white PET film or a black PET film, and the thickness of the PET film is preferably 20 to 50 μm, more preferably 25 to 40 μm, and specifically, in an embodiment of the present invention, it can be 20 μm, 25 μm or 50 μm.

[0053] When the aluminum-coated base film is a two-layer PET aluminum-coated film, the total thickness of the reflective sheet for preventing warping and wrinkles is preferably 70 to 160 μm, more preferably 80 to 150 μm, and most preferably 80 to 110 μm. Specifically, in an embodiment of the present invention, it can be 70 μm, 80 μm, 90 μm, 110 μm or 160 μm.

[0054] In the present invention, no matter which of the above two structures is used, an uncoated PET film is arranged on the top of the reflective sheet for preventing warping and wrinkles. Since the silver-coated base film is prone to bulge in a long-term heated environment, resulting in problems with the reflected light path and the original reflection intensity cannot be maintained, the uncoated PET film shrinks after being heated, causing the silver-coated base film to warp in the direction of the uncoated PET film, and finally reaching a balance with the bulge generated by the silver-coated base film, thereby solving the problem of silver film warping caused by the large amount of heat absorbed by the aluminum film.

[0055] The LCD reflector in the present invention is mainly composed of a PET silver-plated film, a supporting film layer is laminated as compensation, or to strengthen the stiffness structure, or to prevent light leakage. The method adopted is to laminate a polyurethane film roll to a flexible functional film, and the process includes the steps of coating, laminating, winding, and aging.

[0056] The present invention further provides a backlight module, wherein the reflective sheet in the backlight module is the reflective sheet for preventing warping and wrinkling as described above.

[0057] The invention provides a reflective sheet for preventing warping and wrinkling, comprising a silver-plated base film, a first adhesive layer, an aluminum-plated base film, a second adhesive layer and a PET film which are in contact with each other in sequence; the aluminum-plated base film comprises one or two layers of PET aluminum-plated films; the aluminum layer in each layer of the PET aluminum-plated films is closer to the silver-plated base film; when the aluminum-plated base film is one layer of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film is 100-1000nm; when the aluminum-plated base film is two layers of PET aluminum-plated films, the thickness of the aluminum layer in the PET aluminum-plated film close to the silver-plated base film is 100-800nm, and the thickness of the aluminum layer in the PET aluminum-plated film close to the PET film is 100-600nm. The present invention adopts a multi-layer aluminum film design so that the reflector is evenly heated under the action of the heat environment and the heat emitted by the LED, etc., thereby avoiding the wrinkles and deformation of the reflector material caused by the influence of the silver LED, etc.; at the same time, the present invention also arranges an uncoated PET layer on the top of the reflector. Under long-term heating or high-temperature environment, the overall film layer of the reflector will warp toward the uncoated PET layer, which can balance the bulge of the silver film caused by heating, and solves the problem of silver film warping caused by the large amount of heat absorbed by the aluminum film.

[0058] In order to further illustrate the present invention, a reflective sheet and a backlight module for preventing warping and wrinkling provided by the present invention are described in detail below in conjunction with embodiments, but it should not be understood as limiting the protection scope of the present invention.

[0059] Examples 1 to 5 The aluminized base film is a two-layer PET aluminized film

[0060] A multilayer reflector was prepared according to the parameters in Table 1, and the performance of the multilayer reflector obtained in Examples 1 to 5 was tested. The test results are shown in Table 2.

[0061] Table 1 Structural parameters of the multilayer reflector in Examples 1 to 5 of the present invention

[0062]

[0063] Table 2 Anti-wrinkle and warping performance test of the multilayer reflective sheet in Examples 1 to 5 of the present invention

[0064]

[0065] Among them, ◎ represents "no wrinkles", ○ represents "slight wrinkles", and △ represents "severe wrinkles".

[0066] The test conditions are in accordance with the industry standards for optical films of LCD backlight modules, and refer to GB / T1740-2007 or ISO4611:2010. The specific test methods are as follows:

[0067] High temperature and high humidity test: The high temperature and high humidity test is carried out in a high temperature furnace at 60°C and 95% RH for 240 hours.

[0068] LED lighting test: put the reflector into the backlight module, light up the LED backlight module (current 0.04MA / voltage 24V) in a high temperature furnace at 70℃ and test for 240HR;

[0069] High temperature storage test: put the reflector into the backlight module in a high temperature furnace at 80℃, and test it continuously for 240HR without turning on the backlight;

[0070] Thermal shock warpage test: refer to IEC 60068-2-14:2009Na or GB / T 2423.22-2012Na, run the reflector between -40℃ and 80℃ at intervals of 30min for 10 consecutive tests.

[0071] The structure of GF-80W2 is PET silver-plated film (25μm) bonded with 3-5μm polyurethane and 50μm PET white film.

[0072] Examples 6 to 10 The aluminized base film is a layer of PET aluminized film

[0073] A multilayer reflective sheet was prepared according to the parameters in Table 3, and the performance of the multilayer reflective sheets obtained in Examples 6 to 10 was tested. The test results are shown in Table 4.

[0074] Table 3 Structural parameters of the multilayer reflector in Examples 6 to 10 of the present invention

[0075] Example Silver-plated PET layer / silver layer Aluminized PET layer / aluminum layer PET layer Total thickness 6 12μm / 60nm 12μm / 100nm 12μm 42μm 7 12μm / 100nm 12μm / 400nm 25μm 55μm 8 25μm / 200nm 12μm / 600nm 12μm 55μm 9 25μm / 120nm 12μm / 600nm 25μm 69μm 10 25μm / 120nm 25μm / 1000nm 25μm 82μm

[0076] Table 4 Performance test of anti-wrinkle and anti-warping of multilayer reflective sheet in Examples 6 to 10 of the present invention

[0077]

[0078]

[0079] Among them, ◎ represents "no wrinkles", ○ represents "slight wrinkles", and △ represents "severe wrinkles".

[0080] The test conditions are in accordance with the industry standards for optical films of LCD backlight modules, and refer to GB / T1740-2007 or ISO4611:2010 test methods.

[0081] High temperature and high humidity test: The high temperature and high humidity test is carried out in a high temperature furnace at 60°C and 95% RH for 240 hours.

[0082] LED lighting test: put the reflector into the backlight module, light up the LED backlight module (current 0.04MA / voltage 24V) in a high temperature furnace at 70℃ and test for 240HR;

[0083] High temperature storage test: Put the reflector into the backlight module in a high temperature furnace, and test it continuously for 240 hours in a high temperature furnace at 80℃ without turning on the backlight;

[0084] Thermal shock warpage test: refer to IEC 60068-2-14:2009Na or GB / T 2423.22-2012Na, run the reflector between -40℃ and 80℃ at intervals of 30min for 10 consecutive tests.

[0085] The structure of GF-80W2 is PET silver-plated film (25μm) bonded with 3-5μm polyurethane and 50μm PET white film.

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A reflective sheet for preventing warping and wrinkling, comprising a silver-plated base film, a first adhesive layer, an aluminum-plated base film, a second adhesive layer and a PET film in contact with each other in sequence; The silver-plated base film comprises a silver-plated PET layer and a silver layer composited on the surface of the PET base film; The thickness of the silver-plated PET layer in the silver-plated base film is 12 to 50 μm; the thickness of the silver layer in the silver-plated base film is 100 to 120 nm; The aluminum-plated base film includes one or two layers of PET aluminum-plated film; the aluminum layer in each layer of the PET aluminum-plated film is closer to the silver-plated base film; When the aluminum-plated base film is a layer of PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film is 600-1000 nm, and the thickness of the aluminum-plated PET layer in the PET aluminum-plated film is 12-25 μm; When the aluminum-plated base film is a two-layer PET aluminum-plated film, the thickness of the aluminum layer in the PET aluminum-plated film close to the silver-plated base film is 300-450nm, and the thickness of the aluminum-plated PET layer in the PET aluminum-plated film close to the silver-plated base film is 10-25nm; the thickness of the aluminum layer in the PET aluminum-plated film close to the PET film is 300-400nm, and the thickness of the aluminum-plated PET layer in the PET aluminum-plated film close to the PET film is 12-25nm; The thickness of the PET film is 20-50 μm.

2. The reflective sheet for preventing warping and wrinkling according to claim 1, characterized in that: When the aluminized base film is two layers of PET aluminized film, the two layers of PET aluminized film are connected by an adhesive layer.

3. The reflective sheet for preventing warping and wrinkling according to claim 1, characterized in that: The PET film is a transparent PET film, a white PET film or a black PET film.

4. The reflective sheet for preventing warping and wrinkling according to claim 1, characterized in that: The aluminized base film is a layer of PET aluminized film, and the total thickness of the reflective sheet is 42 to 82 μm; The aluminized base film is a two-layer PET aluminized film, and the total thickness of the reflective sheet is 70-160 μm.

5. A backlight module, characterized in that: A reflective sheet for preventing warping and wrinkling according to any one of claims 1 to 4.

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