TWI232603B - LED backlight module - Google Patents

Abstract

The present invention provides an LED backlight module including a back-bezel, a plurality of LEDs, a diffusion plate and a diffusion sheet. Said LEDs are set on the back-bezel. The diffusion plate is set above said LEDs and comprising a plurality of optical microstructures on its surface. And the diffusion sheet is set above the diffusion plate by a predetermined height. The light from said LEDs occurs total reflection on the surfaces of both diffusion plate and sheet, this causing the light mixing adequately in the LED backlight module. Then the light leaves the LED backlight module through the upper surface of the diffusion sheet. Within, said optical microstructures are needed for turning the light toward the diffusion sheet.

Description

1232603 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to an LED (1ightemit ΐ indi ode) backlight module, in particular to an LED backlight module with an auxiliary diffuser plate, and Auxiliary diffuser. [Previous technology] LED (Light Emitting Diode) light source will have breakthrough help for liquid crystal display products, the main reason is that the LED's luminous efficiency has been greatly improved, it is generally believed that the current stage of LED, technically has The efficiency of cold cathode lamps is about half, and even in 2005, the luminous efficacy of LEDs is expected to go hand in hand with cold cathode lamps. Of course, this is only in terms of LED brightness. If the high response speed characteristics of LEDs are applied, and the three LED light sources, red, blue, and green, are sequentially switched on and turned on at high speed, it can replace high-priced color filters in liquid crystal panels and increase the fineness of liquid crystal display products. Fatness and brightness ◦ From this perspective, the impact of LED light sources on the future development trend of liquid crystal display products will be comprehensive and thorough. In addition to being applied to liquid crystal display products, once the luminous efficacy of LEDs can be equal to (or exceed) that of cold-cathode lamps, its application will inevitably be expanded. For example, LED lamps have been used in many signal light sources. , Such as traffic lights and traffic lights, if the light-emitting efficiency has progressed, the most likely application is to extend it to the lighting source, and LED has low power consumption and low heating characteristics , Will pose a great threat to all current lighting sources.

Page 6 1232603 V. Description of the invention (2) 凊 Refer to Figure 1, which is a side sectional view of a conventional LED backlight module. The LED backlight module 10 includes a frame 12, a plurality of LEDs 14, a reflection sheet 16 and a diffusion sheet 18. Since the LED backlight module 10 shown in FIG. 1 is arranged at the bottom, the upper surface of the diffusion sheet 18 above it is the light exit surface of the LED backlight module 10, thereby providing light to The LCD panel ** is usually called a direct-type backlight module. _ Among them, a plurality of L E D 1 4 are arranged on the bottom plate of the frame 12 to serve as a light source in the l £ d backlight module 10. As shown in Fig. 1, L E D 1 4 can be divided into a light emitting region 1 4 1 in the upper half and a base 1 4 3 in the lower half. · The reflection sheet 16 can reflect the light from the light-emitting area 1 4 1 of the LED 14 upward _, so that the light can be fully used. The reflection sheet 16 is erected on the frame 12 with its edge portion, and a plurality of LED holes are provided therein so that the light-emitting area 141 of the LED 14 passes through and is located on the reflection sheet 16; the base 143 is on the reflection sheet 1 Below 6 is a base 1 4 3 series which can be used in some conventional techniques: to support the reflection sheet 16. The light-transmitting diffusion sheet 18 is also erected on the frame 12 by using its edge portion. By making the material of the diffusion sheet 18 different from the refractive index of the air, part of the light incident on the diffusion sheet 18 can be totally reflected. As shown in Fig. 1, the light is reflected or totally reflected between the diffuser 18 and the reflector 16 multiple times, which can improve the mixing effect of the various colors of light emitted by [£ 1 4], so that the chromaticity and brightness of the light After being more uniform, the LED backlight module 丄 0 is removed from the upper surface of the diffusion sheet 18 again. Generally speaking, the reason why the LED backlight module 1 〇 particularly needs to emphasize the mixed light effect of various colors of light is that the individual LED 1 4 series can produce red, green,

1232603 V. Description of the invention (3) 葭 and other different colors, such as “αα 土 # 雨 #, light”, but the LED backlight module 1 is provided to the liquid crystal panel imaging C: chroma and brightness, otherwise it will become a subsequent liquid e has a good mixing ^ Γ S prime. Therefore, ′ is required in the LED backlight module 10, so that the light emitted from the LED backlight module 10 has a uniform degree and color P. Going to Λ &, Qi Yu's thinking, because LED 1 4 is side-emitting (si de 2 1 2 is not the same as Λ is the backlight module 10 shown in Figure 1, LE D14 side of the LED14 side square ^^ Shooting / green emits upwards, but emits light toward γ repeatedly, and when the LED backlight 桓 is emitted from the reflector U and the diffuser 18, and the light is only Λ 2… 1 angle). Strong angle If If ^ Figure II, Figure II shows the LED luminous intensity arrow: the light path at an angle of about 80 degrees from the normal line l in Figure II (such as within the angle of the degree: then = the strongest position of 2 degrees, refer to At its plus or minus 2. When the LED generates #, it is the range of light to be emitted. From this figure, we can see that most of the springs are indeed emitting light toward its side. It is necessary to have :: You know, in the light module It is necessary to make it right, so that the ud backlight module mention # 之 # 靖 八 has uniform chromaticity and brightness. However, first, first, 'provided by the spring module ,, said. Control you from As shown in the first example of the familiar LED back, the / first mechanism still needs to be improved. Shibu is in the better mixing room for LED backlight modules. The characteristics of surface light, Avoid two; :: still taking into account the light] Gen good results with this first actuator

1232603 V. Description of the invention (4) "-and sacrificed the overall luminous efficiency of the LED backlight module. = Xuanzhong is still lacking—a kind of light that can take into account both: the LED backlight grip of the fruit, 7w ° Aunt Jiuzheng, and Yichang #Learning technology mixed light effect is not a bird & 111 r ί # ^ Fff1 # ^ ^ ^ # ^ ^ ^ Two ^, and can be quickly and easily integrated into the existing King of LED backlight module clothing, in order to facilitate the industry's competitiveness in cost and other aspects. , T :: Yu! Research and development personnel in related fields of LED backlight modules, while solving the shortcomings of the conventional technology, so as to further improve the quality of LED backlight module products. 4 迠 [Summary of the Invention] The main purpose of the present invention is to provide an LED backlight module with a mixed light effect. The photoluminescence rate of the member turtle is another purpose of the present invention is that Fuyi can quickly and easily integrate into the existing LE type LEDe light module, which can be used in the module manufacturing process. The LED backlight module system provided by the present invention, LED, a reflection sheet, a diffusion sheet, and a ** several parts of the frame of the LED backlight module

The reflective sheet, the diffuser sheet, and the two-light module in the plurality of LEDs are arranged on the bottom plate of the frame '^ an L light emitting area and a base. Individual led systems are available; ^ Dagger includes a color light. ’, Three red, green and blue

1232603 V. Description of the invention (5) The reflective sheet wood δ is on the frame, which has a plurality of led holes, which can be fitted on the outside of the LED so that the light-emitting area of the LED is located on the reflective sheet, and the base of the LED is located on Under the reflection sheet and carrying the reflection sheet. The auxiliary diffusion plate is mounted on the frame and is arranged above the LED; the surface of the auxiliary diffusion plate has a plurality of optical microstructures. The diffusion sheet is mounted on the frame and is arranged above the auxiliary diffusion plate at a predetermined height. The LED backlight module uses the upper surface of the diffusion sheet as a light emitting surface.

The diffusion sheet and the auxiliary diffusion plate are transparent. And because the refractive index of the material of the diffusion sheet and the auxiliary diffusion plate is different from that of air, the light generated by these LEDs can be caused by total reflection on the surface of the auxiliary diffusion plate and the diffusion sheet, and reflection on the surface of the reflection sheet. In the LED backlight module, the light is sufficiently mixed, and the LED backlight module is separated from the light emitting surface. The optical microstructures on the surface of the auxiliary diffusion plate are used to guide the light inside the LED backlight module to the diffusion sheet and the light emitting surface above.

The present invention provides an LED backlight module having both luminous efficiency and light mixing effect. The present invention provides an LED backlight module having both a diffusion sheet and an auxiliary diffusion plate, which has a good light mixing effect. The improvement of the auxiliary diffuser plate improves the disadvantage that the LED backlight module of the prior art has poor luminous efficiency. In addition, the new technology developed by the present invention has excellent convenience in manufacturing, and can be quickly and easily integrated into the existing lEd backlight module manufacturing process. At the same time, the auxiliary diffusion plate of the present invention further brings the effect of improving the brightness of the LED moonlight module. In this way, the invention not only meets the cost and manufacturing considerations of the industry, but also has considerable progress.

1232603

It is beneficial to improve the competitiveness of the industry. [Implementation method] Η. Figures 3 and 3 are side cross-sectional views of the LED backlight module of the present invention. L: The 40 series includes a frame 42 having a bottom plate, a plurality of LEDs 44, a reflection sheet 46, a diffusion sheet 48, and a diffusion plate 52. Month and month 48 and a supplement

The bottom plate 421 is a part of the frame 42 of the LED backlight module 40, and is made of a compound material such as aluminum or magnesium or a PC material. The frame 42 can carry the LEDs 44, the reflection sheet 46, the diffusion sheet 48, and the auxiliary diffusion plate 52 in the led backlight module 40. A plurality of LEDs 44 are disposed on the bottom plate 421, and each of the LEDs 44 includes a light-emitting area 441 and a base 4 4 3. Individual LED44 series can produce three colors of red, green and blue. The reflection sheet 46 is mounted on the frame 42 and has a plurality of LED holes 46 that can be fitted on the outside of the LED 44 so that the light emitting area 441 of the LED 44 is located on the reflection sheet 46 and the base 44 3 of the LED 44 is located on the reflection sheet. 46 下 ， 和 carrying reflection sheet 46. It is worth noting that, above the reflecting sheet 46, and provided with the auxiliary diffusion plate 5 2 provided by the present invention, which is erected on the frame 4 2 'and is disposed above the LED 4 4; the surface of the auxiliary diffusion plate 5 2 The system has a plurality of optical microstructures 5 2 1. As shown in FIG. 3, in one embodiment of the present invention, the above optical microstructures 5 2 1 are formed on the upper surface of the auxiliary diffusion plate 52. The diffusion sheet 4 8 is mounted on the frame 4 2 and is disposed at a predetermined height.

Page 11 1232603 V. Description of the invention (7) 52ΐΓ LED backlight module 40 is based on the diffuser sheet 48 as the output surface. In an embodiment of the invention, the predetermined height is between 25 mm and 35 mm and the auxiliary diffusion plate 52 has a thickness of about ⑽ ⑽. According to the LED backlight module 40 of the present invention shown in FIG. 3, the 'expansion 48' and the auxiliary diffusion plate 52 are transparent. However, the “refraction index” of the diffuser plate 48 and the auxiliary diffuser plate 52 is different from that of the material. The refractive index of the material is different from that of the hollow-shaped shooter. The result of refracting the sheep by j% work is that these LEDs are produced by 44 kg. The light rays can be mixed in the LED moonlight frame 40 by the t reflection generated on the surface of the auxiliary diffusion plate 52 and the diffusion plate 48 and the reflection generated on the surface of the reflection plate 46. (The upper surface of the diffuser sheet 48) leaves the LED backlight module 40. The optical microstructures 52 1 on the surface of the auxiliary diffuser plate 52 are used to guide the light inside the LEDf light module 40 easily to the upper side of the LEDf light module 40. The optical microstructure 5 2 1 of the diffuser sheet 48 and the light-emitting surface shown in FIG. 3 (see arrow a) on the upper surface of the auxiliary diffuser 5 2 can change its optical path, and the diffuser sheet 4 is directed upward. 8 (such as arrow a). A layer of reflective film (not shown) can be laid on the surface of the side wall of the frame 4 2 and the reflective sheet 4 6, such as E60L silver produced by Toray Company. Reflective film to reduce the loss of light during multiple reflections. Considering the overall optical uniformity of the LED backlight module 40 step by step, a specular reflector (ESR dot, enhanced specular reflector) can be formed on the lower surface of the auxiliary diffusion plate 52 and corresponding to the position directly above each LED 44. ) 5 2 3 to prevent LED40 directly

Page 12 1232603 V. Description of the invention (8) The light emitted upward destroys the overall optical uniformity of the LED backlight module 40. Because the conventional LED backlight module has the dilemma of luminous efficiency and mixed light effect, but for liquid crystal display products that value light chromaticity and brightness uniformity, it is also desirable to use the one shown in Figure 2. LED backlight module to meet the needs of fully mixed light. Therefore, the LED backlight module 40 provided by the present invention has an auxiliary diffusion plate 52, and the optical microstructures 5 2 1 on the surface of the auxiliary diffusion plate 52 can increase the surface area of the auxiliary diffusion plate 52 and increase the surface area of the auxiliary diffusion plate 52. Opportunity for light emission; and by forming the optical microstructures 5 2 1 on the upper surface of the auxiliary diffusion plate 5 2 instead of a flat surface design, the incident angle and flatness of light on the upper surface of the auxiliary diffusion plate 5 2 are made flat. The surface is different, and it is less likely to generate total reflection and easy to emit light, so as to direct the light inside the LED backlight module 40 to the diffusion sheet 48 above it. As one of the reasons for the poor luminous efficiency of conventional LED backlight modules is that LEDs are side-emitting (sideemi 11: ing), most of the light generated by them is not directly emitted to the upper light emitting surface, as shown in the figure. As shown in Figure 3, the main light emitting angle of the LED is within a range of 80 degrees from the normal L and plus or minus 20 degrees. Therefore, the optical microstructures 5 2 1 on the surface of the auxiliary diffusion plate 5 2 according to the present invention are light rays that can help the side of the LED 4 4 to emit light, and part of the light is between the auxiliary diffusion plate 5 2 and the reflection sheet 46. Light reflected back and forth (or total reflection) corrects it

Page 13 1232603 V. Description of the invention (9) The light path is guided to the diffusion sheet 48. This can make the auxiliary diffusion plate 52 to increase the overall chromaticity and brightness uniformity, but not to reduce the luminous efficiency of the LED backlight module. ,

In practice, the material of the auxiliary diffusion plate 52 may be selected from acrylic materials (PMMA), polycarbonate materials (PC materials), or cycloolefin polymer materials (COPs, Zeonor). The formation of the microstructure 521 can be provided in advance with a structure corresponding to the optical microstructure 5 2 1 on a mold for manufacturing the auxiliary diffusion plate 5 2 so that the optical microstructure 5 2 1 is injection-molded on the auxiliary diffusion plate 5 2. Made in one piece. In another embodiment, the optical microstructure 521 may be a v_cut structure, and a V-cut scraper may be used to form an original acrylic material (ρ μ μ a), a polycarbonate material (pc material), or a cycloolefin. Polymeric materials (C0Ps,

The desired optical microstructure 521 is formed on the surface of the Zeonor) to form the auxiliary diffusion plate 52 of the present invention. In this regard, the auxiliary diffusion plate provided by the present invention has excellent convenience in manufacturing.

Take the optical microstructure 521 of the V-cut structure as an example. As shown in FIG. 3, a plurality of v-cut structures (optical microstructure 521) arranged in parallel & Because its structure is similar to 稜鏡, it can have the effect of collecting light; and because the individual V-cut structure is very small, and each V-CuU ^ distribution is quite even, its light-collecting effect does not cause LED ^ = The backlight module 40 has uneven brightness and improved brightness. The design and distribution density of 疋 ’V-cut structure worthy of consideration must be considered

1232603 V. Description of the invention (10) It measures the actual light output of the backlight, and can be used to fill the dark areas and increase the overall brightness. According to an embodiment of the present invention, the distance between two adjacent V-cuts in the V-cut structure may be between 1 and 300 / im; and, depending on whether there is a dark area on the light emitting surface of the actual LED backlight module 40, Then, the interval distance of the V-cu 暗 structure corresponding to the position of the dark area can be set to be short (the density of the V-cut structure is higher) to increase the brightness of the dark area and thereby improve the uneven light output caused by the dark area. The height of individual V-c u ΐ structures can be tens of // m. In addition to the considerations mentioned above in implementing the present invention, when the LED backlight module 40 of the present invention is applied to a liquid crystal display product, conventional optical films can be used on the diffusion sheet 48 to improve the overall optical performance, such as Upper and lower diaphragms, upper and lower diffusers ... and so on. Please refer to FIG. 4, which is a side sectional view of another embodiment of the present invention. In addition to the embodiment shown in FIG. 3, the optical microstructure 5 2 1 in the present invention may also be disposed on the lower surface of the auxiliary diffusion plate 52 as shown in FIG. 4. In terms of the quality of light provided, the difference between the LED backlight module 50 in Fig. 4 and the LED backlight module 40 in Fig. 3 is not far behind. FIG. 5 is a side sectional view of another embodiment of the present invention. In the LED backlight module 60, the optical microstructure 5 2 1 a is disposed on the upper surface of the auxiliary diffusion plate 5 2, and the optical microstructure 5 2 1 b is disposed on the lower surface of the auxiliary diffusion plate 52. Six are perspective views of the auxiliary diffusion plate 5 2 of FIG. 5, in which the optical microstructure 5 2 1 a and the optical microstructure 5 2 1 b are arranged perpendicular to each other.

Page 151232603 V. Description of the invention (11) Taking the V-cut structure as an example, the V-cut structure can be used to form V-cut structures on the upper and lower surfaces of the auxiliary diffuser plate 52 in a direction perpendicular to each other, so as to realize the figure 6 Show the auxiliary diffuser 5 2. The advantage of this implementation mode is that the light collection effect of the LED backlight module caused by the optical microstructure will not only be evenly distributed in the form of fine parallel lines, but also uniformly distributed in the form of dots arranged in an array. To sum up, the present invention provides an LED backlight module that can take into account both luminous efficiency and light mixing effect. The present invention provides an LED backlight module with both a diffusion sheet and an auxiliary diffusion plate. Light mixing effect, and by using the optical microstructure of the auxiliary diffusion plate, it is possible to avoid sacrificing the light emitting efficiency of the LED backlight module while improving the light mixing effect. Furthermore, the new technology developed by the present invention has excellent manufacturing convenience. It can be quickly and easily integrated into the existing LED backlight module manufacturing process. At the same time, the auxiliary diffuser plate of the present invention further brings the effect of improving the brightness of the LED backlight module. The optical microstructure can adjust the distribution density to improve the dark area of the light emitting surface of the LED backlight module and improve the uniformity of light. In this way, the invention not only meets the industry's cost and manufacturing considerations, but also has considerable progress, which is conducive to improving the competitiveness of the industry.

Although the present invention is explained as above with a preferred example, it is not intended to limit the spirit and the entity of the present invention, but only to the above-mentioned embodiments. For those who are familiar with this technology, it is easy to understand and use other components or methods to produce the same effect. Therefore, modifications made without departing from the spirit and scope of the present invention I

Page 16 1232603

Page 12322603 Brief description of the drawings [Simplified description of the drawings] The above detailed description and the many advantages of this invention can be easily understood through the following detailed description combined with the attached drawings, among which: Figure 1 is a conventional LED Side sectional view of the backlight module; Figure 2 shows the angular range of strong LED luminous intensity; Figure 3 is a side sectional view of the LED backlight module of the present invention; Figure 4 is a side sectional view of another embodiment of the present invention; A side sectional view of another embodiment of the present invention; and FIG. 6 is a perspective view of the auxiliary diffuser plate of FIG. 5.

[Figure number comparison table] LED backlight module 1 0, 20, 40, 50, 60 Frame 1 2, 42 LED14, 44 Light-emitting area 141, 441 Base 143, 443 Reflective sheet 16, 46 Diffusion sheet 1 8, 4 8 Base plate 4 2 1 LED hole 46 1 Auxiliary diffusion plate 52 Optical microstructure 5 2 1, 5 2 1 a, 5 2 1 b Mirror reflection sheet 5 2 3

Arrow a, a ’normal line L

Claims (1)

1232603 Correction to increase the state day: / 洚-: --- VI. Patent application scope ♦ 1. An LED backlight module includes: a base plate; a plurality of LEDs arranged on the base plate; an auxiliary diffusion A plate is disposed above the LED, the surface of the auxiliary diffusion plate has a plurality of optical microstructures; and a diffusion sheet is disposed above the auxiliary diffusion plate at a predetermined height. The LED backlight module is formed of the diffusion sheet. The upper surface is a light-emitting surface. 2. The LED backlight module according to item 1 of the scope of patent application, wherein the predetermined height between the auxiliary diffusion plate and the diffusion sheet is between 25mm ~ 3 5mm 〇3. As described in item 1 of the scope of patent application The LED backlight module, wherein the optical microstructures are formed on an upper surface of the auxiliary diffusion plate. 4. The LED backlight module according to item 1 of the scope of patent application, wherein the optical microstructures are formed on the lower surface of the auxiliary diffusion plate. 5. The LED backlight module according to item 1 of the scope of patent application, wherein the optical microstructures are formed on the upper and lower surfaces of the auxiliary diffusion plate. 6. The LED backlight module according to item 1 of the scope of patent application, wherein the above optical microstructures are V-cut structures. Amendment of MJL 1232603 on page 19 6. Scope of patent application 7 • The optical microstructures on the surface of the auxiliary diffusion plate of the LED backlight module described in item 5 of the patent application are perpendicular to the lower surface of the auxiliary diffusion plate The optical microstructures. 8. The backlight module according to item 1 of the scope of the patent application, wherein the material of the auxiliary diffusion plate is selected from the group consisting of acrylic materials, polycarbonate materials, and cycloolefin polymer materials. 9. The LED backlight module according to item 1 of the scope of patent application, wherein the light generated by the LEDs is totally reflected between the optical microstructure and the surface of the diffusion sheet, and the LED backlight module The light is sufficiently mixed in the medium and leaves the LED backlight module from the light emitting surface. 10. An auxiliary diffuser plate used in an LED backlight module. The LED backlight module includes at least a base plate, a plurality of LEDs, and a diffusion sheet. The LEDs are placed on the bottom plate, and the diffuser sheet. It is arranged above the LED, so that the light generated by the LED is totally reflected on the diffusion sheet, and the LED backlight module is emitted from the upper surface of the diffusion sheet, wherein the auxiliary diffusion plate is used to enhance the LED backlight module. The internal light mixing effect is arranged between the LED and the diffusion sheet, and is a predetermined height away from the diffusion sheet, and the surface of the auxiliary diffusion plate has a plurality of optical microstructures for directing light above it. Diffuser. 11. The auxiliary diffusion plate as described in item 10 of the scope of patent application, wherein Amendment on page 20: AV »· ,,, 1232603 VI. Patent Application Range The predetermined height between the auxiliary diffuser and the diffuser is between 25mm and 3 5mm 〇 1 2. In the auxiliary diffusion plate, the optical microstructures are formed on an upper surface of the auxiliary diffusion plate. 1 3. The auxiliary diffusion plate as described in item 10 of the scope of patent application, wherein the optical microstructures are formed on the lower surface of the auxiliary diffusion plate. 14. The auxiliary diffusion plate as described in item 10 of the scope of patent application, wherein the optical microstructures are formed on the upper and lower surfaces of the auxiliary diffusion plate. 15. The auxiliary diffuser plate as described in item 10 of the scope of patent application, wherein the optical microstructures are V-cut structures. 16. The auxiliary diffusion plate according to item 14 of the scope of the patent application, wherein the optical microstructures on the surface of the auxiliary diffusion plate are perpendicular to the optical microstructures on the lower surface of the auxiliary diffusion plate. 1 7. The auxiliary diffusion plate according to item 10 of the scope of patent application, wherein the material of the auxiliary diffusion plate is selected from the group consisting of acrylic materials, polycarbonate materials, and cycloolefin polymer materials. Page 21