TW202312529A - Thin direct type backlight module - Google Patents

Abstract

A thin direct type backlight module is disclosed. A thin film circuit board of the thin direct type backlight module is used to carry the Mini LEDs, the thin film circuit board is completed by defining a plurality of circuit structures on the upper surface of the thin film circuit board in the etching process, and the upper surface of the thin film circuit board has a mesh support structure that is simultaneously formed in the same etching process and is of the same material. A reflective paint of the thin direct type backlight module is painted on the thin film circuit board and position for the Mini LEDs is reserved. A thin light guide plate of the thin direct type backlight module is laminated on the reflective paint and is provided with a plurality of through holes to accommodate the Mini LEDs after the punching process, and the bottom surface of the thin light guide plate is equipped with optical dots to adjust the uniformity of the light output after the through holes receives the Mini LEDs light. An optical glue of the thin direct type backlight module is used to fill the corresponding through holes in order to cover the Mini LED after the thin light guide plate and the film circuit board are bonded. Through the above structure, the overall thickness of the back light module can be effectively reduced, and the purpose of thinning can be achieved.

Description

Thin direct type backlight module

The invention relates to the field of backlight modules, in particular to a thin direct-lit backlight module.

The backlight module is a light supply product commonly used in various electronic devices. It has the advantage of providing uniform light in a planar shape, and is the preferred light source for displays or luminous keyboards. Based on the current technology and product requirements, electronic devices using backlight modules are mostly developing towards thinning. Therefore, as a member of electronic device components, relevant manufacturers have also begun to devote themselves to improving and adjusting the thickness of the backlight module.

According to the relative position of the light source and the light guide element, the backlight module can be divided into two types in principle: direct type or side type. sideways. Taking the direct-type backlight module as an example, most of them adopt the method of thinning and improving the light guide element to reduce the overall thickness. In addition, there are also improvements to the structure of the light source to find another way to reduce the thickness. Taking the circuit components in the traditional light source structure as an example, they are generally implemented using flexible or rigid circuit boards. The disadvantage of rigid circuit boards is that they are thicker, which is no longer suitable for today's thinning requirements. Flexible circuit boards are wired after wiring. After the processing process, there are problems such as insufficient rigidity and poor electrical contact. In the part of the light guide element, the light utilization rate of the light source and the assembly and installation of the light source must also be considered under the thin design. These problems are in electronic devices such as luminous keyboards that require complicated wiring and light source settings. It is even more influential. Therefore, how to further thin the backlight module, and at the same time, have a good configuration and combination between the light source structure and the light guide element, and have a satisfactory light output performance in application is an urgent problem to be solved at present.

In view of this, the inventor of the present invention conceived and proposed a thin direct-lit backlight module based on years of rich technical experience in related industries, so as to effectively solve various deficiencies of current backlight modules.

One purpose of the present invention is to provide a thin direct-type backlight module, which is specially designed for the circuit and light guide structure, so as to effectively reduce the thickness of the backlight module, so as to make the electronic products used in conjunction with thinness and excellent light output Performance application requirements.

In order to achieve the above purpose, the present invention proposes a thin direct type backlight module in one embodiment, including: a thin film circuit board, used to carry a plurality of sub-millimeter light-emitting diodes, which is made of a copper foil film in a wet etching process The plurality of circuit structures defined in the above is completed on its upper surface, and the upper surface of the thin film circuit board has a plurality of mesh support structures that are formed simultaneously and of the same material in the same etching process mentioned above. The pattern range of each mesh support structure is It is defined by at least one circuit structure frame; a reflective coating is printed on the thin film circuit board, and the mounting position of the plurality of sub-millimeter light-emitting diodes is reserved; a thin light guide plate is stacked on the On the reflective coating, the thin light guide plate is provided with a plurality of through holes for accommodating the sub-millimeter light-emitting diodes after the punching process, and the lower surface of the thin light guide plate is provided with a plurality of optical dots to adjust the The light output uniformity of the through holes after receiving the light of the sub-millimeter light-emitting diodes; and a plurality of optical adhesives, which are used to fill in the corresponding through holes in sequence after the thin light guide plate and the thin film circuit board are bonded. The holes cover the plurality of submillimeter light-emitting diodes. In this way, the traditional FPCB structure is replaced by a specially designed thin film circuit board, which can effectively reduce the thickness of the backlight module. At the same time, the thin film circuit board is formed in the same etching process to form a mesh support structure to strengthen the thin film circuit board. Structural strength; and through the dot layout of the light guide plate, and the through-hole structure are used to accommodate and receive sub-millimeter light-emitting diodes, so as to eliminate the inconvenience of light reception after thinning.

It is disclosed in one embodiment that the reflective paint is white ink, which has the advantages of easy application and high reflective performance.

In addition, in order to better shield light leakage, in another embodiment, the lower surface of the thin film circuit board has a light-shielding paint.

In yet another embodiment, the lower diameter of the through holes of the thin light guide plate is smaller than the upper diameter, so as to reduce the air gap at the position adjacent to the sub-millimeter light-emitting diodes and increase the amount of light entering.

Further, based on the above-mentioned embodiment, based on the consideration of the convenience of the manufacturing process and the precision of the formed structure, in another embodiment, the through holes of the thin light guide plate are cut from the top of the thin light guide plate through a knife die. Made, and the knife mold a slope.

In order to improve the concealment and uniform light effect, in one embodiment, the thin direct-type backlight module further includes a shielding sheet stacked on the thin light guide plate. The shielding sheet includes a diffuse reflection sheet body and a light-shielding layer. The diffusion reflector body has a plurality of openings; the light-shielding layer is coated on the upper surface of the diffuse reflection sheet body, and the light-shielding layer is sandwiched with the edges of each opening to form a blank area, wherein the light-shielding layer The white area has a light-transmitting property.

Based on the technology of the above-mentioned embodiment, in another embodiment, the shielding sheet further has a plurality of downwardly extending convex ribs for passing through the plurality of positioning holes of the thin light guide plate, and then sticking against the film circuit board , to enhance the overall fixing strength and resist expansion and contraction.

To sum up, the thin direct type backlight module proposed by the present invention replaces the traditional FPCB with a specially designed thin film circuit board, so that the thin film circuit board has excellent structural rigidity and meets the requirements of thinning at the same time. Adjusting the structural characteristics of the thin light guide plate will effectively avoid the problem of unfavorable light reception by the light guide plate, and improve the use efficiency of the sub-millimeter light-emitting diodes and the uniformity of the overall light output, thereby greatly improving the light quality of the backlight module. Further, based on the requirement of improving various performances, the present invention also proposes more detailed technical features, as described in the above embodiments.

Thinning is one of the important development directions and requirements of today’s backlight module products. The current difficulty lies in the lack of rigidity and the problem of alignment with the light guide element when thinning the circuit board. When the thinning is used as a design method, it will cause the problems of low light utilization rate and light uniformity. Therefore, how to avoid the above-mentioned problems while having a thinner structure will be a difficult problem that needs to be overcome urgently. Based on this, the inventor proposes a thin-type direct-lit backlight module, whose film circuit board structure effectively replaces the traditional FPCB, and can still maintain the rigidity of the circuit board in the case of extremely thin thickness, while the light guide performance part, It is to effectively overcome the problems of low light utilization rate, uneven light output or insufficient brightness faced by thin light guide plates. Hereinafter, the thin direct type backlight module of the present invention will be described in combination with words and figures. Wherein, the structural dimensions shown in each figure, such as thickness, length and width, etc., are only for illustrating and explaining the technical features of the present invention, and do not represent actual rulers and regulations, and are described first.

Please refer to FIGS. 1A and 1B , which are partial exploded schematic diagrams of a thin direct type backlight module according to an embodiment of the present invention and partial exploded schematic diagrams from another viewing angle. Among them, the structural modeling or setting and distribution state shown in each figure are for illustrative purposes only, and do not represent the actual structural size or shape. The thin direct type backlight module 1 includes a thin film circuit board 10 , a reflective paint 11 , a thin light guide plate 12 and a plurality of optical adhesives 13 . The thin direct-lit backlight module 1 can be applied to a light-emitting keyboard as a light source for the light-emitting keyboard, so that each key can obtain light to realize light emission.

The thin film circuit board 10 is used to carry a plurality of sub-millimeter light-emitting diodes 2 (Mini LEDs). The thin film circuit board 10 is completed by defining a plurality of circuit structures 101 on its upper surface in a wet etching process of a copper foil film, and The upper surface of the thin film circuit board 10 has a plurality of mesh support structures 102 formed simultaneously in the same etching process and made of the same material. The pattern range of each mesh support structure 102 is defined by at least one circuit structure 101 . In other words, the mesh support structure 102 is located on the upper surface of the thin film circuit board 10 where there is no circuit structure 101, so the pattern range of the mesh support structure 102 will form a state surrounded by at least one circuit structure 101, The distribution pattern of the mesh support structure 102 and the line structure 101 is not limited to that shown in FIG. 1A .

In practice, the thin film circuit board 10 can be made of a thin polyimide substrate plus copper foil. Polyimide is a type of high molecular polymer (Polyimide, PI for short, a copper foil is provided on the PI film, and the circuit structure 101 and the mesh support structure 102 are formed synchronously after a wet etching process. The upper surface of the thin film circuit board 10 can be used to arrange the sub-millimeter light-emitting diodes 2 through the assembly process. The circuit structure 101 of the thin-film circuit board 10 is used to electrically connect the sub-millimeter light-emitting diodes 2, and the grid The shape support structure 102 is used to enhance the stiffness of the thin film circuit board 10 to avoid warping and deformation during subsequent processes. Specifically, the thickness of the thin film circuit board 10 is in principle less than 0.5 mm. For example, in an implementation state, the thickness of the PI base film plus the copper foil is only about 30.5 μm. After the sub-millimeter light-emitting diode 2 is arranged on the upper surface of the thin-film circuit board 10 and punched, it will be baked in a tin furnace to fix the sub-millimeter light-emitting diode 2. At this time, in such a thin case, the thin-film circuit board Insufficient structural stiffness of the board 10 will result in curling deformation. Therefore, after the thin film circuit board 10 of this embodiment is subjected to a wet etching process, the circuit structure 101 for forming electrical conduction is left, and a mesh support structure 102 is simultaneously formed in the area to be removed by etching, so that The mesh support structure 102 eliminates the internal stress generated by the baking process, and prevents curling and deformation. It is particularly worth mentioning that during the design process, the inventors also conducted tests by keeping the complete copper foil in the area of the film circuit board 10 outside the circuit structure 101 that was originally planned to be etched and removed. When the entire copper foil is reserved for the baking process, the entire copper foil is also baked together, resulting in internal stress, which worsens the degree of deformation. Therefore, in other words, whether the area of the thin film circuit board 10 to be etched and removed is to completely remove the copper foil or keep a complete sheet of copper foil, it cannot resist the deformation caused by the baking process. Therefore, the mesh support structure 102 must be used to eliminate internal stress and prevent deformation. In addition, the feature of the mesh support structure 102 of the present invention is that it can absorb internal stress during the manufacturing process to enhance structural stiffness and provide support performance. Therefore, in other fields, there may be disclosures of mesh structures made of conductive materials, such as mesh ground layers or circuit lines applied to fibers, etc. These mesh structures are only used as structures for electrical conduction , which is completely different from the purpose and effect of the present invention for improving structural stiffness. Other similar mesh applications can also be found in the fields of touch control, battery units, or anti-EMI. However, these mesh applications are the same as the above-mentioned ones, and they are all related to electricity without the effect of rigid support and improving structural stiffness. It should not be confused with the mesh support structure 102 of the present invention.

Next, the reflective paint 11 is printed on the thin film circuit board 10 , and the mounting positions of the submillimeter light-emitting diodes 2 are reserved. In practice, when the reflective paint 11 is printed on the thin film circuit board 10, the area where the sub-millimeter light-emitting diode 2 is to be placed will be left blank, so as to facilitate the subsequent setting of the sub-millimeter light-emitting diode 2. Please refer to Section 1A here. As shown in the figure. The reflective paint 11 can replace the structure of the reflective sheet, which helps to reduce the thickness of the thin direct type backlight module 1 .

The thin light guide plate 12 is stacked on the reflective paint 11 , and the thin light guide plate 12 has a plurality of through holes 121 for accommodating the submillimeter light emitting diodes 2 after the molding process. The lower surface of the thin light guide plate 12 is provided with a plurality of optical dots 122 to adjust the uniformity of the light emitted by the through hole 121 after receiving the light from the submillimeter light-emitting diode 2 . In a specific application, in an implementation state, the thickness of the thin light guide plate 12 can be less than 0.3 mm, and it can be a relatively thin sheet structure. Wherein, because the thickness of the thin light guide plate 12 is quite thin, it is not feasible to provide blind holes for accommodating sub-millimeter light-emitting diodes 2 on the thin light guide plate 12, because the thin light guide plate 12 is generally made of such as PC, etc. It is made of plastic, so it has resilience. If a blind hole is provided, it will be difficult to injection mold, and it will not be able to stably form the shape of the lamp cup formed by the sub-millimeter light-emitting diode 2 . Therefore, the structure on the thin light guide plate 12 for accommodating the submillimeter light-emitting diode 2 must be a through hole 121 . In addition, setting the optical dots 122 on the lower surface of the thin light guide plate 10 also has functional significance. Experimental tests have proved that when the optical dots 122 are placed on the lower surface, the use efficiency of the submillimeter light-emitting diodes 2 can be effectively improved by about 46 %, the uniformity of light output can be improved by about 13%, and it has a significant optimization effect on the quality of light output. And when the thin direct-type backlight module 1 is applied to a luminous keyboard, the optical dots 122 can be set at the predetermined assembly positions corresponding to the keys, so that the keys can obtain light. Among them, the arrangement state of the optical network dots 122 shown in FIG. 1B is only to illustrate the structural features of the lower surface of the thin light guide plate 12, and its scale, size and distribution density are only for illustration, and do not represent the actual arrangement state.

Please also refer to FIG. 2 here, which is a schematic diagram of a combination of a thin direct-lit backlight module according to an embodiment of the present invention. After the thin light guide plate 12 is attached to the thin film circuit board 10 , the optical glue 13 can be disposed in each through hole 121 . In other words, the optical adhesive 13 is used to sequentially fill the corresponding through holes 121 after laminating the thin light guide plate 12 and the thin film circuit board 10 , and to cover the submillimeter light emitting diodes 2 . In this way, the submillimeter light-emitting diode 2 can be effectively protected.

Through the above-mentioned technical features, the thin direct-type backlight module 1 proposed by the present invention achieves the purpose of thinning through the copper foil laminated structure, and eliminates the deformation problem that is easy to occur after thinning the circuit board through the mesh support structure 102 . At the same time, aiming at the light utilization rate of the thin light guide plate 12, the uniformity of light output, and the combination with the submillimeter light-emitting diode 2 and the thin film circuit board 10, the structure of the through hole 121 and the optical dots 122 arranged on the lower surface are also used. To solve the problem, a thinner product with excellent use efficiency and structural strength is provided. In particular, the thin film circuit board 10 is different from the traditional FPCB in that it is a thin film circuit board with a mesh support structure 102 and a circuit structure 101 made by one-time etching, and the reflective coating 11 can be used to omit the setting of reflection. In this way, the overall thickness can be effectively reduced. Therefore, compared with the traditional backlight module with FPCB and the backlight module with reflectors, the thin direct-type backlight module 1 of the present invention has the above-mentioned features, and To achieve a further thinning effect. After the thin film circuit board 10 and the thin light guide plate 12 are attached to each other, the sub-millimeter light-emitting diode 2 can be accommodated through the through hole 121, so as to achieve the functions of precise alignment and receiving light. The millimeter light-emitting diode 2 can be almost completely accommodated in the through hole 121 , which helps to increase the amount of light received by the thin light guide plate 12 , thereby improving the utilization rate of light.

Further, the reflective paint 11 can be made of white paint, so as to have excellent reflective effect, instead of the reflective sheet. On the other hand, the lower surface of the thin film circuit board 10 may have a light-shielding paint 103 , such as printing black ink, to shield possible light leakage and improve the overall light-emitting effect.

Please refer to FIG. 3 for further matching, which is a schematic cross-sectional view of a partial assembly of a thin direct-lit backlight module according to an embodiment of the present invention. In order to improve the performance of the through hole 121 in receiving the light from the sub-millimeter light-emitting diode 2, in an implementation state, the lower diameter of the through-hole 121 of the thin light guide plate 12 can be made smaller than the upper diameter, so that the light-emitting diode can be placed close to the sub-millimeter light-emitting diode. The body 2 position narrows the air gap to increase the amount of light entering. Wherein, in order to facilitate the description of the above-mentioned structural features, the overall structure is simply shown in FIG. 3 , and some elements, such as the circuit structure 101 , the mesh support structure 102 , the reflective paint 11 and the light-shielding paint 103 , are omitted.

As for the formation method of the through holes 121, in an application state, the through holes 121 of the thin light guide plate 12 are cut from the top of the thin light guide plate 12 through a die, and the die is inclined. Through the aforementioned knife film cutting method, the extruded material can be made at the bottom, and the air gap can be further reduced to increase the amount of light entering. When the through hole 121 is made in the above manner, in principle, the inner surface of the through hole 121 will form an extruding surface 1211 and an inclined surface sequentially connected from top to bottom in response to the top-to-bottom cutting movement of the knife die. 1212 and extrusion surface 1213. And when the angle θ of the inclined surface 1212 in the through hole 121 changes more, the amount of light entering increases accordingly. For example, when the angle θ of the inclined surface 1212 is 90 degrees, that is, when the upper and lower diameters of the through hole structure are equal, sub-millimeter light is emitted. The amount of light entering the diode 2 can be 100%; when the angle θ of the slope 1212 is 85 degrees, the amount of light entering increases to 102%; when the angle θ of the slope 1212 is 80 degrees, the amount of light entering increases to 105%; the angle θ of the slope 1212 is At 75 degrees, the amount of incoming light increases by 107%, which roughly shows that the amount of incoming light increases by 2% for every change of 5 degrees.

For the thin direct type backlight module 1 , the data of the experimental examples that can be implemented are presented below. In this experimental example, the overall thickness of the thin film circuit board 10 is 0.075mm, the reflective paint 11 is white paint and the reflectivity is 75%, the material of the thin light guide plate 12 is PC, and the thickness is 0.2mm, and the diameter above the through hole 121 is 1.184mm, the bottom diameter is 0.911mm, the thickness of the submillimeter LED 2 is 0.18mm, and the optical glue 13 is UV glue with a refractive index of 1.5. For more detailed gauge data, the vertical length of the extrusion surface 1211 is 0.034mm, the vertical length of the inclined surface 1212 is 0.145mm, and the vertical length of the extrusion surface 1213 is 0.019mm. However, the above-mentioned various gauge data are only information of an experimental example, and cannot be used to limit the feature range of the thin direct-lit backlight module.

Please refer to Figures 4 and 5 again, which are partial exploded schematic diagrams and partial assembled cross-sectional schematic diagrams of a thin direct type backlight module according to another embodiment of the present invention. Based on the previous description of the embodiments, the same technical features will not be repeated here, and the same components are described with the same reference numerals. In order to improve the quality of the light output of the thin direct-type backlight module 1, and to prevent uneven brightness or partial bright spots caused by some unnecessary light output, when the thin-type direct-type backlight module 1 is applied to a light-emitting keyboard, it is The above-mentioned adverse phenomenon can be avoided by painting the bottom of the iron parts in the luminous keyboard black, but this method has poor concealment and uniform light effect. Therefore, the present invention also proposes a corresponding solution to this problem, that is, to make the thin direct-type backlight module 1 further include a shielding sheet 14, which is stacked on the thin light guide plate 12, and the shielding sheet 14 includes a diffuse reflective sheet body 141 and a light-shielding layer 142, the diffuse reflector body 141 has a plurality of openings 1411, the light-shield layer 142 is coated on the upper surface of the diffuse reflector body 141, and the light-shield layer 142 is interposed with the edges of each opening 1411 to form a gap The white area 143, wherein the blank area 143 has a light-transmitting property. Through the masking sheet 14, the effect of concealing blemishes and uniform light can be achieved, so that the performance of light emission is more excellent and meets the requirements. Among them, in order to facilitate the description of the above-mentioned structural features, the overall structure is simply shown in FIG. 5 , and some components, such as the circuit structure 101 , the mesh support structure 102 , the reflective paint 11 and the light-shielding paint 103 , are omitted.

When designing the structure of the shielding sheet 14, the inventor stacked other components on the thin direct-lit backlight module 1, such as the keys of the light-emitting keyboard, for testing. Firstly, when the thin direct type backlight module 1 is not provided with the shielding sheet 14, although the thin light guide plate 12 has the highest average luminance because there is no shielding sheet on the top side, the light can be reflected back into the thin light guide plate 12, but However, there are insufficient light uniformity, light leakage, and uneven brightness and darkness. Then choose a shielding sheet structure without openings and completely coated with light-shielding material. At this time, the light is absorbed because the shielding sheet does not have a reflective area, so the average luminance will drop by about 20% after installation, which will cause the problem of insufficient light brightness. , the effect of light adjustment is still insufficient. Another test is to open a hole in the shielding sheet to confirm whether the light will not be directly absorbed by the shielding sheet because it can pass through the hole. However, after the test, it is found that the reflected light will still be blocked by the shielding sheet, so the average luminance does not change. It has been improved, and the effect of adjusting the light is still not enough. With the above-mentioned shielding sheet 14 structure with blank area 143 stacked behind the thin light guide plate 12, the bright spot where the light is bounced by the key can be eliminated by the blank area 143 to form a uniform aperture, which solves the problem of large-angle light leakage. The problem of uneven light and dark, and has the effect of concealing and evening light. Here, the through-hole 121 is taken as an example with the same diameter at both ends, but when the above-mentioned through-hole 121 has a structure in which the lower diameter is smaller than the upper diameter, the shielding sheet 14 can also be added.

Further, please refer to FIG. 6 , which is a schematic cross-sectional view of a partial assembly of a thin direct-lit backlight module according to a second embodiment of the present invention. In this embodiment, the shielding sheet 14 further has a plurality of downwardly extending ribs 144 for passing through the plurality of positioning holes 123 of the thin light guide plate 12 , and then sticking against the thin film circuit board 10 . Let the shielding sheet 14 pass through the positioning hole 123 through the convex rib 144, which can achieve excellent overall fixing and anti-expansion and contraction effects, so as to prevent the heat energy brought by the action of the sub-millimeter light-emitting diode 2 from causing the alignment assembly of each component. Influence. Wherein, the protruding ribs 144 can be disposed adjacent to the opening 141 of the shielding sheet 14 , or disposed at any position of the shielding sheet 14 . And here, the through hole 121 is taken as an example in which both ends have the same diameter, but when the aforementioned through hole 121 has a structure in which the lower diameter is smaller than the upper diameter, a shielding sheet 14 can also be added. Wherein, in order to facilitate the description of the above-mentioned structural features, the overall structure is simply shown in FIG. 6 , and some components, such as the circuit structure 101 , the mesh support structure 102 , the reflective paint 11 and the light-shielding paint 103 , are omitted.

To sum up, the thin direct-type backlight module disclosed in the present invention has excellent structural rigidity and light emitting performance while achieving the purpose of thinning. Aiming at the problem that the thinned light guide plate is not easy to align and fix and receive light, it is solved through the design of the through hole, and for the structure of the circuit board that provides electrical properties, the thin direct type backlight module of the present invention is connected with the circuit The mesh support structure formed in the same etching process greatly improves the structural stiffness of the thinned film circuit board, and effectively prevents the curling deformation caused by the baking process after the sub-millimeter light-emitting diodes are stamped. Further thinning the circuit board design. As for the performance of various aspects of the thin direct-lit backlight module, detailed technical features that can be further added are also proposed in the above content, such as the choice of reflective coatings, or the need for shielding light leakage and adjusting the state of light, which can make the film circuit board under the Install light-shielding paint on the surface, or cover the thin light guide plate with a shielding sheet, etc., and consider the light utilization efficiency, so that the upper diameter of the through hole is larger than the lower diameter, so as to receive more incident light. To reiterate here, the thin direct type backlight module has successfully thinned the laminated light guide plate and light source components to achieve the effect of reducing the overall thickness, overcoming various difficulties encountered in reducing the thickness of backlight module products in the past, Regardless of structural strength, rigidity, or light guide and light output performance, the thin direct-lit backlight module is solved and improved by specific technical means. Through the film-shaped circuit board with a mesh support structure and a circuit structure that has a one-time etching process, the curling deformation caused by the baking process is eliminated, and the film-shaped circuit board is effectively fixed by sub-millimeter light-emitting diodes after baking. After the body, its structure is still maintained, and at the same time, the reflector element is omitted by the reflective paint, and the overall thickness is relatively reduced. As for the part of the light guide plate that is too thin to obtain enough incident light or the uniformity of light output is difficult to adjust, it is solved by the through-hole design and the optical dots on the lower surface. Therefore, the thin direct-type backlight module is actually a thinned laminated backlight module product proposed by means different from the prior art.

1: Thin direct type backlight module 10: Thin film circuit board 101: Line structure 102: Mesh support structure 103: Blackout paint 11: Reflective paint 12: Thin light guide plate 121: through hole 1211: extrusion surface 1212: Bevel 1213: extrusion surface 122: Optical dots 123: Locate the hole 13: Optical glue 14: masking film 141: Diffuse reflector body 1411: opening 142: shading layer 143: blank area 144: convex rib 2: Submillimeter LEDs θ: slope angle

FIG. 1A is a partial exploded view of a thin direct-lit backlight module according to an embodiment of the present invention. FIG. 1B is a partially exploded schematic diagram of another viewing angle of a thin direct-type backlight module according to an embodiment of the present invention. Fig. 2 is a schematic diagram of a combination of a thin direct type backlight module according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of a partial assembly of a thin direct type backlight module according to an embodiment of the present invention. Fig. 4 is a partial exploded view of a thin direct-lit backlight module according to another embodiment of the present invention. Fig. 5 is a schematic cross-sectional view of a partial assembly of a thin direct type backlight module according to another embodiment of the present invention. Fig. 6 is a schematic cross-sectional view of a partial assembly of a thin direct type backlight module according to a second embodiment of the present invention.

1: Thin direct type backlight module

10: Thin film circuit board

101: Line structure

102: Mesh support structure

11: Reflective paint

12: Thin light guide plate

121: through hole

2: Submillimeter LEDs

Claims (7)

A thin direct type backlight module, comprising: A thin film circuit board, used to carry a plurality of sub-millimeter light-emitting diodes, is completed by defining a plurality of circuit structures on the upper surface of a copper foil film in a wet etching process, and the upper surface of the thin film circuit board has a In the above-mentioned same etching process, a plurality of network support structures of the same material are formed simultaneously, and the pattern range of each network support structure is defined by at least one line structure frame; A reflective paint, printed on the film circuit board, and reserved for the mounting positions of the plurality of submillimeter light-emitting diodes; A thin light guide plate stacked on the reflective coating, the thin light guide plate is provided with a plurality of through holes for accommodating the sub-millimeter light-emitting diodes after the punching process, and the lower surface of the thin light guide plate A plurality of optical dots are provided to adjust the uniformity of light emitted by the through-holes after receiving the light from the sub-millimeter light-emitting diodes; and A plurality of optical adhesives are used to fill in the corresponding through-holes sequentially after laminating the thin light guide plate and the film circuit board, and to cover the plurality of submillimeter light-emitting diodes. The thin direct type backlight module according to Claim 1, wherein the reflective paint is white ink. The thin direct type backlight module according to Claim 1, wherein the lower surface of the thin film circuit board has a light-shielding paint. The thin direct type backlight module according to claim 1, wherein the diameter of the bottom of the through holes of the thin light guide plate is smaller than the diameter of the top. The thin direct type backlight module according to claim 4, wherein the through holes of the thin light guide plate are cut from the top of the thin light guide plate downwards through a knife mold, and the knife mold has an inclined surface. The thin direct-type backlight module as described in Claim 1 further includes a shielding sheet stacked on the thin light guide plate, the shielding sheet includes a diffused reflective sheet body and a light-shielding layer, and the diffused reflective sheet body There are a plurality of openings; the light-shielding layer is coated on the upper surface of the diffuse reflector body, and the light-shielding layer is sandwiched with the edges of each opening to form a blank area, wherein the blank area has a light-transmitting property . The thin direct-lit backlight module according to claim 6, wherein the shielding sheet further has a plurality of downwardly extending ribs for passing through the plurality of positioning holes of the thin light guide plate, and then affixed against the thin light guide plate. thin film circuit boards.

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