A ceramic composite reflective sheet and a backlight module

Abstract

The present invention provides a ceramic composite reflector, which comprises a first PET layer, a silver layer, a first adhesive layer, a ceramic layer, a second PET layer, a second adhesive layer and a support layer in contact in sequence; the thickness of the support layer is 1 / 3 to 2 / 3 of the thickness of the first PET layer; the ceramic layer contains 85 to 100 wt% of Al2O3 and 0 to 15 wt% of additives, and the additives are SiO2 and / or TiO2. In the present invention, a ceramic layer is added in the middle of the reflector, and additives such as SiO2 are added, so that the heat conduction continuity of the ceramic layer mainly composed of alumina is better, and heat can be more effectively dispersed. At the same time, by arranging the reflector between two PET film layers, the shrinkage and bending effects of the silver layer and the aluminum layer can also be balanced, making the structure of the reflector more stable. The present invention also provides a backlight module.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid crystal display backlight modules, and particularly relates to a ceramic composite reflector and a backlight module. Background Art

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

[0003] The backlight module includes a lighting source, a reflector, a light guide plate, a diffusion sheet, a brightness enhancement film (prismatic sheet), and a frame, etc. The backlight modules used in LCDs can be mainly divided into two categories: side-light type backlight modules and direct-light type backlight modules. Mobile phones, laptop computers, and monitors (15 inches) mainly use side-light type backlight modules, while most liquid crystal TVs use direct-light type backlight module light sources. The backlight module light source mainly uses a light-emitting diode (LED) light source as the backlight of the LCD.

[0004] The existing commercially available reflector is composed of two PET films laminated together, generally laminated by a silver-plated reflector and a black or white reflector, or an aluminized film. In order to ensure that the backlight module maintains excellent performance under various environmental conditions, especially in the high-temperature environment during the operation of electronic products, the backlight module will undergo a high-temperature test before leaving the factory to detect the high-temperature operation performance of the backlight module. However, in the existing technology, the reflector in the backlight module often generates white film, black film, or wrinkles in the aluminized film in a high-temperature environment, resulting in the inability to guarantee its performance under high-temperature operating conditions. Summary of the Invention

[0005] The purpose of the present invention is to provide a ceramic composite reflector and a backlight module. The ceramic composite reflector in the present invention can solve the problem of warping of the reflector at high temperature.

[0006] The present invention provides a ceramic composite reflector, including a first PET layer, a silver layer, a first adhesive layer, a ceramic layer, a second PET layer, a second adhesive layer, and a support layer that are in contact in sequence;

[0007] The thickness of the support layer is 1 / 3 to 2 / 3 of the thickness of the first PET layer;

[0008] The ceramic layer contains ceramic powder, and the ceramic powder is 90 to 100 wt% of Al2O3 and 0 to 10 wt% of an additive, and the additive is SiO2 and / or TiO2.

[0009] Preferably, the support layer is a transparent PET film, a white PET film, a black PET film or a PET aluminized film;

[0010] The PET aluminized film is a PET layer coated with an aluminum layer, and the aluminum layer therein is in contact with the second adhesive layer.

[0011] Preferably, the thickness of the support layer is 10-20 μm; the thickness of the first PET layer is 20-40 μm.

[0012] Preferably, the thickness of the ceramic layer is 0.5-5 μm;

[0013] The thickness of the second PET layer is 35-45 μm.

[0014] Preferably, the ceramic layer is prepared by coating with a ceramic slurry, and the ceramic slurry includes ceramic powder, polyurethane glue and ethyl acetate; the ceramic powder contains 85-100 wt% of Al2O3 and 0-15 wt% of additives, and the additives are SiO2 and / or TiO2.

[0015] Preferably, the mass ratio of the ceramic powder to the polyurethane glue is (5-20):(40-60).

[0016] Preferably, the solid content of the ceramic slurry is 10-30%.

[0017] Preferably, the total thickness of the ceramic composite reflector is not more than 85 μm.

[0018] The present invention provides a backlight module, including the ceramic composite reflector described above.

[0019] The present invention provides a ceramic composite reflector, including a first PET layer, a silver layer, a first adhesive layer, a ceramic layer, a second PET layer, a second adhesive layer and a support layer in contact in sequence; the thickness of the support layer is 1 / 3-2 / 3 of the thickness of the first PET layer; the ceramic layer contains 85-100 wt% of Al2O3 and 0-15 wt% of additives, and the additives are SiO2 and / or TiO2. The present invention finds through research that in the prior art, the shrinkage rates of the silver layer and the aluminum layer are different in a high-temperature environment, and both are prone to bending in their own directions, resulting in an unstable structure of the reflector, and thus unstable warping. The present invention adds a ceramic layer in the middle of the reflector and adds additives such as SiO2, so that the ceramic layer mainly composed of alumina has better heat conduction continuity and can more effectively disperse heat. At the same time, setting the reflector between two PET film layers can also balance the shrinkage and bending effects of the silver layer and the aluminum layer, making the structure of the reflector more stable. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0021] Figure 1 It is a schematic structural diagram of a ceramic composite reflector in an embodiment of the present invention.

[0022] Among them, 1 is the first PET layer, 2 is the silver layer, 3 is the first adhesive layer, 4 is the ceramic layer, 5 is the second PET layer, 6 is the second adhesive layer, and 7 is the support layer. Detailed implementation manners

[0023] The present invention provides a ceramic composite reflector, including a first PET layer, a silver layer, a first adhesive layer, a ceramic layer, a second PET layer, a second adhesive layer, and a support layer that are in contact in sequence;

[0024] The thickness of the support layer is 1 / 3 to 2 / 3 of the thickness of the first PET layer;

[0025] The ceramic layer contains 85 to 100 wt% of Al2O3 and 0 to 15 wt% of additives, and the additives are SiO2 and / or TiO2.

[0026] In the present invention, the thickness of the first PET layer is preferably 20 to 40 μm, more preferably 25 to 35 μm, and most preferably 25 to 30 μm; specifically, in the embodiments of the present invention, it can be 25 μm.

[0027] The thickness of the silver layer is preferably 100 to 150 nm, more preferably 110 to 140 nm, and most preferably 120 to 130 nm. Specifically, in the embodiments of the present invention, it can be 100 nm, 110 nm, 120 nm, 130 nm, or 140 nm.

[0028] In the present invention, the thickness of the first adhesive layer is preferably 3 to 4 μm.

[0029] In the present invention, the main components of the ceramic layer include ceramic powder, and the ceramic powder includes Al2O3. Preferably, it further includes additives SiO2 and / or TiO2. The mass fraction of Al2O3 in the ceramic powder is preferably 85-100%, more preferably 90-95%. The mass fraction of the additives in the ceramic powder is preferably 0-15%, more preferably 5-10%. Specifically, in the embodiments of the present invention, it can be 5% or 10%. In the present invention, adding some SiO2 and / or TiO2 to Al2O3 can make up for the defects of Al2O3 and make the thermal conductivity of the coating more continuous. However, if the addition amount of the additive is too small, the modification effect is not good; if the addition amount of the additive is too large, it is likely to cause a decrease in the thermal conductivity of the coating.

[0030] In the present invention, the particle size of Al2O3 in the ceramic powder is preferably 30±5μm, the particle size of SiO2 is preferably 35±5μm, and the particle size of TiO2 is preferably 35±5μm;

[0031] The thickness of the ceramic layer is preferably 0.5-5μm, more preferably 1-4μm, and most preferably 1.5-3.5μm. Specifically, in the embodiments of the present invention, it can be 1.0μm, 1.5μm, 2.0μm or 3.0μm.

[0032] In the present invention, the ceramic coating is prepared by coating ceramic slurry, and the specific steps are as follows:

[0033] The prepared ceramic slurry is coated on the surface of the PET film layer by roll-to-roll gravure coating. The coating temperature is preferably 100-130°C, more preferably 110-120°C, and the coating speed is preferably 30-50m / min, more preferably 40m / min.

[0034] In the present invention, the ceramic slurry includes ceramic powder, polyurethane glue and ethyl acetate, and the composition of the ceramic powder is the same as that of the ceramic powder described above, which will not be elaborated here.

[0035] In the present invention, the ceramic powder and polyurethane glue are mixed evenly, and then ethyl acetate is added to adjust the solid content to 10-30% to obtain the ceramic slurry.

[0036] In the present invention, the mass ratio of the ceramic powder to the polyurethane glue is preferably (5 - 20):(40 - 60), more preferably (10 - 15):(45 - 55), and most preferably 10:50. The solid content of the ceramic slurry is preferably 10 - 30%, more preferably 15 - 25%, and most preferably 20%. In the present invention, the solid content of the ceramic slurry affects the thickness of the ceramic layer to a certain extent. For example, a ceramic slurry with a solid content of 10% is more suitable for coating a 1.0 μm coating, a ceramic slurry with a solid content of 15% is more suitable for coating a 1.5 μm coating, a ceramic slurry with a solid content of 20% is more suitable for coating a 2.0 μm coating, and a ceramic slurry with a solid content of 30% is more suitable for coating a 3.0 μm coating.

[0037] In the present invention, the thickness of the second PET layer is preferably 35 - 45 μm, more preferably 38 - 40 μm. Specifically, in the embodiments of the present invention, it can be 38 μm.

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

[0039] In the present invention, the support layer is preferably a transparent PET film, a white PET film, a black PET film, or a PET aluminized film; wherein, the PET aluminized film is a PET layer coated with an aluminum layer, and the aluminum layer is in contact with the second adhesive layer. The thickness of the aluminum layer is preferably 150 - 250 nm, more preferably 180 - 220 nm, and most preferably 200 - 210 nm. Specifically, in the embodiments of the present invention, it can be 180 nm, 190 nm, 200 nm, 210 nm, or 220 nm.

[0040] The thickness of the support layer is preferably 10 - 20 μm, more preferably 12 - 18 μm, and most preferably 12 - 15 μm. Specifically, in the embodiments of the present invention, it can be 12 μm.

[0041] In the present invention, the thickness of the support layer is preferably 1 / 3 - 2 / 3 of the thickness of the first PET layer, more preferably 1 / 2. Under this thickness relationship, it is more beneficial to the structural stability of the reflective sheet in the present invention and can avoid warping.

[0042] The present invention also provides a backlight module, and the reflective sheet in the backlight module is the ceramic composite reflective sheet described above.

[0043] In the present invention, other components in the backlight module, such as a light guide plate, a diffusion sheet, a brightness enhancement film, etc., can all adopt related components commonly used in the art, and the present invention does not make special restrictions on this.

[0044] The present invention provides a ceramic composite reflector, which comprises a first PET layer, a silver layer, a first adhesive layer, a ceramic layer, a second PET layer, a second adhesive layer and a support layer in contact in sequence; the thickness of the support layer is 1 / 3 to 2 / 3 of the thickness of the first PET layer; the ceramic layer contains 85 to 100 wt% of Al2O3 and 0 to 15 wt% of additives, and the additives are SiO2 and / or TiO2. The present invention finds through research that in the prior art, the shrinkage rates of the silver layer and the aluminum layer of the reflector are different in a high-temperature environment, and both are prone to bending in their own directions, resulting in unstable structure of the reflector and thus unstable warping. The present invention adds a ceramic layer in the middle of the reflector and adds additives such as SiO2, so that the ceramic layer mainly composed of alumina has better heat conduction continuity and can disperse heat more effectively. At the same time, setting the reflector between two PET film layers can also balance the shrinkage and bending effects of the silver layer and the aluminum layer, making the structure of the reflector more stable.

[0045] In order to further illustrate the present invention, the following provides a detailed description of a ceramic composite reflector and a backlight module provided by the present invention in conjunction with embodiments, but it should not be construed as a limitation to the protection scope of the present invention.

[0046] Examples 1 to 3

[0047] Ceramic powders with components of Al2O3, 90% Al2O3 + 10% SiO2, and 90% Al2O3 + 10% TiO2 were mixed evenly with polyurethane glue at a mass ratio of 10 (glue): 50 (ceramic powder), and then ethyl acetate was added to adjust the solid content to 10 to 30%. By means of roll-to-roll gravure coating, at a machine speed of 40 m / min and a temperature of 110 °C, coating was carried out on the surface of a 38-μm-thick PET film to obtain a PET layer coated with a ceramic layer, and the thickness of the ceramic layer was adjusted according to the solid content of the ceramic slurry.

[0048] A silver-coated PET film (silver layer 120 nm, PET thickness 25 μm), a PET layer coated with a ceramic layer, and an aluminum-coated PET layer (aluminum layer thickness 200 nm, PET layer thickness 12 μm) were laminated to obtain a reflector.

[0049] The reflectors in Examples 1 to 3 were subjected to performance tests, and the results are shown in Table 1.

[0050] Table 1 Performance test results of the reflectors in Examples 1 to 3 of the present invention

[0051]

[0052]

[0053] Examples 4 to 6

[0054] Ceramic powder materials with compositions of Al2O3, 95% Al2O3 + 5% SiO2, and 95% Al2O3 + 5% TiO2 were mixed with polyurethane glue at a mass ratio of 10 (glue): 50 (ceramic powder materials). After being uniformly mixed, ethyl acetate was added to adjust the solid content to 10 - 30%. By means of roll-to-roll gravure coating, at a machine speed of 40 m / min and a temperature of 110 °C, coating was carried out on the surface of a 38-μm-thick PET film sheet to obtain a PET layer coated with a ceramic layer, and the thickness of the ceramic layer was adjusted according to the solid content of the ceramic slurry.

[0055] A silver-plated PET film sheet (silver layer 120 nm, PET thickness 25 μm), a PET layer coated with a ceramic layer, and an aluminum-plated PET layer (aluminum layer thickness 200 nm, PET layer thickness 12 μm) were laminated to obtain a reflector.

[0056] The reflectors in Examples 4 - 6 were subjected to performance tests, and the results are shown in Table 2.

[0057] Table 2 Performance test results of the reflectors in Examples 4 - 6 of the present invention

[0058]

[0059] Examples 7 - 9

[0060] Ceramic powder materials with compositions of Al2O3, 80% Al2O3 + 20% SiO2, and 80% Al2O3 + 20% TiO2 were mixed with polyurethane glue at a mass ratio of 10 (glue): 50 (ceramic powder materials). After being uniformly mixed, ethyl acetate was added to adjust the solid content to 10 - 30%. By means of roll-to-roll gravure coating, at a machine speed of 40 m / min and a temperature of 110 °C, coating was carried out on the surface of a 38-μm-thick PET film sheet to obtain a PET layer coated with a ceramic layer, and the thickness of the ceramic layer was adjusted according to the solid content of the ceramic slurry.

[0061] A silver-plated PET film sheet (silver layer 120 nm, PET thickness 25 μm), a PET layer coated with a ceramic layer, and an aluminum-plated PET layer (aluminum layer thickness 200 nm, PET layer thickness 12 μm) were laminated to obtain a reflector.

[0062] The reflectors in Examples 7 - 9 were subjected to performance tests, and the results are shown in Table 3.

[0063] Table 3 Performance test results of the reflectors in Examples 7 - 9 of the present invention

[0064]

[0065] In Tables 1 to 3, the data in the column of "Warpage height (mm) at 80°C (240 h) high-temperature storage" are represented by the warpage heights of the silver layer and the aluminum layer. For example, 0-2 means that the warpage height of the silver layer is 0 mm and the warpage height of the aluminum layer is 2 mm.

[0066] The test conditions are the in-line specification criteria for the optical film of the LCD backlight module, and refer to GB / T 1740-2007 or ISO4611:2010. The specific test method is as follows:

[0067] Running test: Place the reflector into the backlight module, and in a high-temperature furnace at 70°C, light up the LED backlight module (current 0.04 mA / voltage 24 V) for testing for 240 h;

[0068] High-temperature storage test: Use a high-temperature furnace to place the reflector into the backlight module, and in a high-temperature furnace at 80°C, continuously test for 240 h without lighting the backlight.

[0069] It can be seen from the data in Tables 1 to 3 that when the addition amount of SiO2 and / or TiO2 is too small, due to the poor thermal conductivity continuity of the Al2O3 powder, warpage is likely to occur. When the addition amount of SiO2 and / or TiO2 is too large, warpage deformation is likely to occur at 80°C / 240 h, and wrinkles are generated due to insufficient thermal conductivity during the 70°C / 240 h test.

[0070] It can be seen from the data in Table 1 that since the ceramic layer is adjacent to the silver layer, the warpage of the aluminized layer is relatively large. After increasing the thickness of the ceramic layer (i.e., increasing the solid content of the ceramic slurry), the warpage decreases until no warpage occurs at 3.0 μm.

[0071] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A ceramic composite reflector, comprising a first PET layer, a silver layer, a first adhesive layer, a ceramic layer, a second PET layer, a second adhesive layer, and a support layer that are sequentially in contact; The thickness of the support layer is 1 / 3 to 2 / 3 of the thickness of the first PET layer; The ceramic layer contains ceramic powder, and the ceramic powder is 90 to 100 wt% of Al2O3 and 0 to 10 wt% of additives, and the additives are SiO2 and / or TiO2; The ceramic layer is prepared by coating with a ceramic slurry, and the ceramic slurry includes ceramic powder, polyurethane glue, and ethyl acetate; the solid content of the ceramic slurry is 10 to 30%; The support layer is a PET aluminized film; the PET aluminized film is a PET layer coated with an aluminum layer, and the aluminum layer therein is in contact with the second adhesive layer.

2. The ceramic composite reflector according to claim 1, wherein, The thickness of the support layer is 10 to 20 μm; the thickness of the first PET layer is 20 to 40 μm.

3. The ceramic composite reflector according to claim 1, wherein The thickness of the ceramic layer is 0.5 to 5 μm; The thickness of the second PET layer is 35 to 45 μm.

4. The ceramic composite reflector according to claim 1, wherein The mass ratio of the ceramic powder to the polyurethane glue is (5 to 20):(40 to 60).

5. The ceramic composite reflector according to claim 1, wherein The total thickness of the ceramic composite reflector is not greater than 85 μm.

6. A backlight module, characterized in that, Including the ceramic composite reflector according to any one of claims 1 to 5.

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