Crossed light bar and backlight module for eliminating firefly phenomenon

Abstract

The application relates to an interlaced light bar and a backlight module for eliminating the firefly phenomenon. The backlight module sequentially comprises a first light bar, a second light bar, a substrate, a reflecting sheet, a light guide plate, a diffusion sheet, a light enhancement sheet, a module edge covering layer, a heat dissipation metal plate, an edge covering light shielding film, a hollow triangular heat dissipation area and a light propagation cavity. The first light bar and the second light bar are designed in an interlaced mode, and the first light bar and the second light bar are both provided with right-angled triangular reflecting platforms. The direct LED range falls on the right-angled triangular reflecting platforms, and then the light is reflected to the light guide plate through the angle design of the reflecting right-angled triangular platforms and the light propagation cavity, and finally the light is reflected to the light guide plate, so that the firefly phenomenon is eliminated. The application can effectively eliminate the firefly phenomenon, the ingenious light propagation cavity design makes the light more effectively reflected and propagated, the utilization rate of the light is increased, the light leakage phenomenon of the backlight module can be prevented under certain conditions, and the heat dissipation of the LED light source is strengthened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of LED backlight, and particularly relates to an interlaced light bar for eliminating firefly phenomenon and a backlight module thereof. BACKGROUND

[0002] With the development of display technology, TFT-LCD technology was born in the 1960s. TFT-LCD has the advantages of color fidelity, clear picture quality, thinness, energy saving, etc., and is widely used in many fields. In addition to TFT-LCD, there are OLED, QLED, Micro-LED and other new display technologies. OLED has become the mainstream display technology due to its excellent characteristics, but its short service life and easy aging. LCD needs a backlight source, which increases the thickness and is contrary to the trend of thinness. The backlight module of LCD can be divided into direct type and side-in type. The side-in type backlight module makes the liquid crystal display thinner and smaller, which meets the trend of lightness and thinness, and is widely used.

[0003] At present, the light source of the side-in type backlight module is replaced by a light bar composed of a plurality of lamp beads instead of the original CCFL light source. Since it is a plurality of non-continuous point light sources, there will be obvious bright and dark alternation phenomenon on the light-in side of the light guide plate, which is called firefly phenomenon or Hot Spots. This seriously affects the picture quality of the backlight module.

[0004] There are several effective solutions to deal with the firefly phenomenon at present. One is to increase the number of LED lamp beads and arrange the lamp beads more closely. However, this solution not only increases the cost, but also generates a large amount of heat due to the close arrangement of the lamp beads, which accelerates the aging of the device. The second is to make a sawtooth microstructure on the light-in side of the light guide plate and cooperate with the local dot adjustment on the light-in side of the light guide plate to soften the strong light area and the weak light area. However, this design is difficult to debug, the effect is not easy to achieve, and it takes a long time to improve.

[0005] Therefore, in order to eliminate the negative influence of the firefly phenomenon in the backlight module on the display effect, researchers have carried out a lot of work. The patent application publication number CN109031785A discloses a lamp strip assembly, a manufacturing method thereof, a backlight module and a display device. The patent application discloses a method for forming a close lamp bead by setting a plurality of stacked lamp strips and a nesting hole between two adjacent lamp beads. The method can alleviate the phenomenon of light and dark alternation on the light-in side of the light guide plate, that is, improve the firefly phenomenon on the light-in side of the light guide plate. However, this improved method still increases the number of LED lamp beads on a single lamp strip, and can only improve the firefly phenomenon to a certain extent. The patent application publication number CN112612074A discloses a backlight module and a display device. The patent application discloses a method for absorbing and reflecting part of the light overflowing from the light guide plate by adding a reflecting sheet with absorption and reflection effects on the upper edge of the light guide plate and the LED light source, so as to improve the firefly phenomenon on the light-in side of the light guide plate. However, this improved structure can only improve the firefly phenomenon to a certain extent, and cannot fundamentally eliminate the firefly phenomenon. SUMMARY

[0006] The present application aims to overcome the shortcomings of eliminating the firefly phenomenon in the existing side-in backlight module, and provide an interleaved lamp strip and a backlight module for eliminating the firefly phenomenon, so as to eliminate the firefly phenomenon.

[0007] In the present application, in view of the shortcomings of increasing cost and heat caused by increasing the number of LED lamp beads on a single lamp strip, a staggered double lamp strip is provided as a light source, and the single lamp strip is regularly and closely arranged by lamp beads and right-angled triangular reflecting tables, effectively solving the heating problem caused by increasing the number of LED lamp beads on a single lamp strip. In view of the shortcomings of light overflow caused by adding a reflecting sheet on the upper edge of the light guide plate and the LED light source, a symmetrical and close light propagation cavity structure is designed. The lamp strip and the light-in side of the light guide plate are reserved a certain light propagation distance, and then the light is reflected to the light-in side of the light guide plate through the angle design of the reflecting right-angled triangular table and the light propagation cavity, effectively solving the light overflow and the firefly phenomenon. Unlike the light source directly attached to the light-in side of the light guide plate, the light source of the present application has a certain light propagation distance from the light-in side of the light guide plate, so the light source area is large. In addition, the design of the reflecting right-angled triangular table and the light propagation cavity structure makes the light source area close, and finally achieves the effect of eliminating the firefly phenomenon. Unlike the method of improving the firefly phenomenon by adding a reflecting sheet, the closed light propagation cavity can more effectively solve the light overflow and the firefly phenomenon.

[0008] In order to achieve the above object, the technical scheme of the present application is: an interleaved light bar for eliminating firefly phenomenon, comprising a first light bar with right-angled triangle reflecting platforms and LED lamps regularly and closely arranged with the right-angled triangle reflecting platforms, a second light bar with right-angled triangle reflecting platforms and LED lamps regularly and closely arranged with the right-angled triangle reflecting platforms, and the light source range of the LED lamps of the first light bar can just fall on the length of the right-angled triangle reflecting platforms of the second light bar; similarly, the light source range of the LED lamps of the second light bar can just fall on the length of the right-angled triangle reflecting platforms of the first light bar, and finally the light is reflected to the light entrance side of the light guide plate of the backlight module. In the traditional design, the light source is directly pasted to the light entrance side of the light guide plate, so that when the light is directly incident into the light guide plate, the light source range falling on the light entrance side of the light guide plate will be small, and when the distance between the LED lamps is large, there will be obvious firefly phenomenon on the light entrance side of the light guide plate; the design of the present application can make most of the light be reflected to the light entrance side of the light guide plate, thereby enhancing the utilization rate of the light and producing a close light source area, so as to eliminate the firefly phenomenon.

[0009] In an embodiment of the present application, the right-angled triangle reflecting platform has the following relationship according to the relationship between the direct light of the Lambertian light source and the direct distance and the reflection law:

[0010] S △ = S LED + 2*x

[0011] x / sin theta = z / sin (90°-theta)

[0012] Wherein, theta is the maximum angle of the outgoing light, which is approximately the included angle between the central optical axis and the outgoing light of the LED lamp; x is the distance between the right end of an LED lamp in the first light bar and the left end of the nearest LED lamp in the second light bar; z is the distance between the upper and lower of the first light bar and the second light bar; S LED is the length of the LED lamps of the first light bar and the second light bar; S △ is the length of the right-angled triangle reflecting platform.

[0013] In an embodiment of the present application, the center distance between the LED lamps of the first light bar and the LED lamps of the second light bar (i.e. the distance of the right-angled triangle reflecting platform plus the length of an LED) can be between 20-21mm, and the distance between the first light bar and the second light bar can be between 2-3mm. The bottom surface of the right-angled triangle reflecting platform covers the entire longitudinal light bar, and the surface is made of ceramic, plastic or metal material, and the outer surface is wrapped with white polyester (PET) reflective film or white polypropylene (PP) reflective film.

[0014] The present application also provides a backlight module using the interleaved light bar for eliminating firefly phenomenon as described above, further comprising a substrate, a reflecting sheet, a light guide plate, a diffusion sheet, a light enhancement sheet and a light propagation cavity for realizing light propagation arranged in sequence from bottom to top.

[0015] In an embodiment of the present application, the light propagation cavity is designed symmetrically up and down, the light emitting surfaces of the first and second light bars are perpendicular to the light in side of the light guide plate, and three hollow triangular heat dissipation regions are arranged on the upper, middle and lower parts of the light propagation cavity, the angle of the hollow triangular heat dissipation region and the angle of the right-angled triangular reflecting platform can make the light of the LED lamp reflect to the light in side of the light guide plate through the light propagation cavity, and the light source and the light in side of the light guide plate have a predetermined light propagation distance. The traditional light propagation cavity design is to add a reflecting sheet on the upper edge of the LED light source or a single light bar with a right-angled platform reflection, which not only misses light and reduces the utilization rate of light, but also cannot ensure that each light emitting part of the LED light source can be effectively reflected to the light in side of the light guide plate. In the design of the present application, the angle of the triangular heat dissipation region and the angle of the right-angled triangular reflecting platform on the light bar can make the light of the LED lamp reflect to the light in side of the light guide plate through the light propagation cavity, and the light source and the light in side of the light guide plate have a certain light propagation distance, so the light source area is large, and the design of the reflecting right-angled triangular platform and the light propagation cavity structure makes the light source area close, thereby finally achieving the effect of eliminating the firefly phenomenon.

[0016] In an embodiment of the present application, according to the geometric optics and the reflection law, the following relationships exist for the light propagation cavity:

[0017] The cross-sectional shape of the light propagation cavity is a shape formed by subtracting three triangular heat dissipation regions from a rectangle, the left lower vertex of the cross-sectional shape of the light propagation cavity and the light guide plate is taken as point A, and the vertices B, C, D, E, F, G, H and I of the cross-sectional shape of the light propagation cavity can be obtained in anticlockwise order, wherein A and D are of the same height, F and I are of the same height, the LED lamps of the first and second light bars are located in the cross-sectional shape of the light propagation cavity, which is a rectangle, and B and H are respectively one vertex of the two LED lamps, and one side of the two LED lamps is respectively a segment of BC and HG; A' is the lower in light critical point of the light in side of the light guide plate, D' is the light out critical point of the left end of the LED lamp of the first light bar, OD is perpendicular to OE and intersects at point O, DD" is perpendicular to DE and intersects at D" point on the LED lamp of the first light bar, and then

[0018] ∠ODE+∠EDA'+∠A'DA=90°

[0019] ∠EDA'+∠A'DA+∠ADD”=90°

[0020] ∠ODE+∠ADD”+∠CDD'=90°

[0021] ∠ADD”=∠D'DD”

[0022] Wherein, ∠D'DD" and ∠ADD" are the incident angle and the exit angle respectively, and ∠ODE, ∠EDA', ∠A'DA and ∠CDD' are the structural parameters of the light propagation cavity.

[0023] In an embodiment of the present application, in the light propagation cavity, BB' is perpendicular to AB' and intersects at point B', the longitudinal distance S of the light guide plate from the LED lamp of the first lamp strip AB' is between 1.0-1.1mm, the transverse distance S of the light guide plate from the right end of the LED lamp of the first lamp strip BB' is between 0.9-1.0mm, the transverse distance S of the light guide plate from the transverse end of the light propagation cavity CB' is between 2.4-2.5mm, the bottom S of the middle hollow triangular heat dissipation area FD is between 2.0-2.1mm, the height S OE is between 0.6-0.7mm, ∠ODE is between 28°-32°, and the angle ∠ABH of the light guide plate and the LED lamp at the right end of the first lamp strip is between 42°-47°.

[0024] In an embodiment of the present application, assuming that the central exit light of the LED lamp of the first lamp strip is reflected by the reflection structure, i.e. the hypotenuse HH', of the right triangle reflection platform of the second lamp strip to the central point E' of the light entry side of the light guide plate, making the corresponding normal line E"H" of HH' intersect HH' at point H" and EE' at point E", by the similarity of △HGH' and ∠H"EE", the following relationship is obtained:

[0025] S HG / S GH' =S H”E / S EE”

[0026] Wherein, △HGH', ∠H"EE", S HG , S GH' , S H”E and S EE” are the structural parameters of the light propagation cavity.

[0027] In an embodiment of the present application, the length S △ of the right triangle reflection platform is between 18-19mm, the width S HG of the right triangle reflection platform is between 1.5-1.6mm, the height S GH' of the right triangle reflection platform is between 0.4-0.5mm.

[0028] The application further provides the staggered light bar for eliminating the firefly phenomenon, which comprises a third light bar of a direct light source and a fourth light bar with a predetermined angle with the third light bar, and the third light bar is provided with a right triangle reflecting platform, the upper part of the light source of the third light bar emits light which is reflected into the light entrance side of the light guide plate, the lower part of the light source of the third light bar emits light which is directly emitted into the light entrance side of the light guide plate, and the critical part of the light emitted from the lower part of the light source of the third light bar is just incident on the light entrance critical point of the light entrance side of the light guide plate; the light emitted from the light source of the fourth light bar is reflected into the light entrance side of the light guide plate through the right triangle reflecting platform of the third light bar, and the critical part of the light emitted from the left part of the light source of the fourth light bar is just at the critical point L of the reflecting structure of the light propagation cavity, and the critical part of the light emitted from the right part of the light source of the fourth light bar is just at the vertex point M" of the right triangle reflecting platform of the third light bar, and finally all the light is incident or reflected to the light entrance side of the light guide plate of the backlight module.

[0029] The application further provides the backlight module adopting the staggered light bar for eliminating the firefly phenomenon, which further comprises a substrate, a reflecting sheet, a light guide plate, a diffusion sheet, a light enhancement sheet and a light propagation cavity for realizing light propagation which are sequentially arranged from bottom to top.

[0030] The cross-sectional shape of the light propagation cavity is a shape formed by subtracting two triangles of a left lower part ∠MLK' and a right lower part ∠KLK" from a rectangle PK"K'N, the cross-sectional shape of the light propagation cavity and the cross-sectional shape of the light guide plate are a rectangle with a left lower vertex as a point J, and in a counterclockwise order, the vertices K, L, M, N and P of the cross-sectional shape of the light propagation cavity can be obtained, a point M' is a wide end point of the right triangle reflecting platform, a point M" is a high end point of the right triangle reflecting platform, the length of the base of the right triangle reflecting platform of the third light bar is between 6.0-7.0mm, the height is between 0.5-0.7mm, the base width is between 1.2-1.4mm, and the base covers a part of the longitudinal light bar; the specification size of the light propagation cavity is respectively S NP between 2.5-2.6mm, S M'K' between 1.3-1.4mm, S K'L between 1.2-1.3mm, S MK' between 0.6-0.7mm, ∠KLK" is between 42°-47°, and ∠MLK' is between 30°-35°.

[0031] Compared with the prior art, the application has the following beneficial effects:

[0032] 1. The staggered light bar design, the LED light bar is opposite, the direct LED range just falls on the reflection right triangle table, then through the angle design of the reflection right triangle table and the light propagation cavity, finally the light is reflected to the light guide plate light side, the LED light source and the light guide plate light side are reserved a certain distance, so that the light can be fully dispersed, finally eliminate the firefly phenomenon, and under the premise of not increasing a large number of lamp beads, avoid the heating problem caused by a dense LED light bar.

[0033] 2. The ingenious light propagation cavity design, the range of light propagation cavity is reduced as much as possible, so that the light can be more effectively reflected and propagated, and the utilization rate of light is increased.

[0034] 3. The reflection cavity and the light guide plate are attached using the edge covering light shielding film; the optical film, the light guide plate and the reflection sheet are tightly attached, the edge covering layer is provided outside the light guide plate light side, the utilization rate of light is enhanced, and light leakage is prevented.

[0035] 4. The hollow triangular area is arranged between the light propagation cavity and the edge covering light shielding film, and the hollow triangular area adopts a stable triangular structure, which increases the stability of the structure and greatly enhances the heat dissipation of the LED light source. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The existing technology diagram for the LED light source of the traditional side-in backlight module to enter the light guide plate;

[0037] Figure 2 The technical diagram of the staggered light bar of the present application for eliminating the firefly phenomenon to enter the light guide plate;

[0038] Figure 3 The first light bar improvement diagram of the present application for eliminating the firefly phenomenon;

[0039] Figure 4 Another aspect diagram of the first light bar of the present application for eliminating the firefly phenomenon;

[0040] Figure 5 The staggered light bar of the present application for eliminating the firefly phenomenon is one aspect diagram;

[0041] Figure 6 Another aspect diagram of the staggered light bar of the present application for eliminating the firefly phenomenon;

[0042] Figure 7 The backlight module intermediate section view of the staggered light bar of the present application for eliminating the firefly phenomenon;

[0043] Figure 8 The aspect diagram of the backlight module of the present application;

[0044] Figure 9Another perspective view of the backlight module of the present application;

[0045] Figure 10 Another embodiment of the light propagation cavity in the backlight module of the present application for eliminating the firefly phenomenon staggered light bar;

[0046] Figure 11 Another light propagation path diagram in the backlight module of the present application for eliminating the firefly phenomenon staggered light bar;

[0047] Figure 12 Another light propagation path diagram in the backlight module of the present application;

[0048] Figure 13 Another light propagation path diagram in the backlight module of the present application;

[0049] Figure 14 Another light propagation path diagram in the backlight module of the present application;

[0050] Figure 15 Another light propagation path diagram in the backlight module of the present application;

[0051] Figure 16 Another light propagation path diagram in the backlight module of the present application;

[0052] Figure 17 Another light propagation path diagram in the backlight module of the present application;

[0053] Figure 18 Another light propagation path diagram in the backlight module of the present application;

[0054] Figure 19 Another light propagation path diagram in the backlight module of the present application;

[0055] Figure 20 Another embodiment of the light propagation cavity in the backlight module of the present application for eliminating the firefly phenomenon staggered light bar;

[0056] Figure 21 Another light propagation path diagram in the backlight module of the present application for another embodiment;

[0057] Figure 22 Another light propagation path diagram in the backlight module of the present application for another embodiment;

[0058] Figure 23 Another light propagation path diagram in the backlight module of the present application for another embodiment;

[0059] Figure 24 Another light propagation path diagram in the backlight module of the present application for another embodiment;

[0060] Figure 25Another light propagation path diagram of another embodiment of the backlight module of the present application;

[0061] Figure 26 Another light propagation path diagram of another embodiment of the backlight module of the present application;

[0062] In the figure: 101-first light bar; 1011-LED light in the first light bar; 10111-light source range of the LED light in the first light bar falling on the light-incident side of the light guide plate; 1012-right triangle reflecting platform of the first light bar; 1041-light-incident side of the light guide plate; 201-second light bar; 2011-LED light in the second light bar; 2012-right triangle reflecting platform of the second light bar; 301-third light bar; 3011-LED light in the third light bar; 3012-right triangle reflecting platform of the third light bar; 401-fourth light bar; 4011-LED light in the fourth light bar; 102-substrate; 103-reflective sheet; 104-light guide plate; 105-diffusion sheet; 106-enhanced light sheet; 107-module edge layer; 108-heat dissipation metal plate; 109-edge light shielding film; 110-hollow triangle heat dissipation area; 111-light propagation cavity. DETAILED DESCRIPTION

[0063] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Note that the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on these embodiments, other embodiments can be obtained by those of ordinary skill in the art without creative efforts, and these embodiments also belong to the protection scope of the present application.

[0064] When describing the embodiments of the present application, it needs to be explained that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the common orientation or positional relationship when the product of the present application is used. This is only for the convenience of description and simplification, and does not indicate or limit that the device or element must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present application.

[0065] Please refer to Figure 1 , which is a prior art diagram showing that the LED light source of the conventional side-in backlight module is incident into the light guide plate. When the LED light 1011 is directly incident into the light guide plate 104, the light source range 10111 of the LED light 1011 falls on the light-incident side 1041 of the light guide plate 104, and when the LED light 1011 has a large spacing, there will be a clear bright-dark alternating phenomenon, i.e. firefly phenomenon, on the light-incident side 1041 of the light guide plate 104. This will cause the picture quality of the backlight module to be seriously affected.

[0066] In order to improve the above problems, please refer to Figure 2It is shown in the technical drawing of the application that the staggered light bar eliminates the firefly phenomenon. Figure 2 The light source of the staggered light bar can compensate the light and dark alternation caused by the firefly phenomenon and avoid the problem that the heat generated by the dense LED light of a light bar is difficult to dissipate without increasing a large number of lamp beads.

[0067] Further, in order to realize the effect of eliminating the firefly phenomenon by the staggered light bar, please refer to Figure 3 and Figure 4 It is shown in the first light bar improvement drawing and the other orientation drawing of the application that eliminates the firefly phenomenon. According to the basic direction of the X, Y and Z axes set by the first light bar 101, the LED light 1011 and the right-angled triangle reflecting platform 1012 are arranged on the first light bar 101. The LED light 1011 and the right-angled triangle reflecting platform 1012 are closely and regularly arranged. The bottom surface covers the entire longitudinal light bar and is made of ceramic, plastic or metal material, and the outer surface is wrapped with white polyester (PET) reflecting film or white polypropylene (PP) reflecting film.

[0068] Please refer to Figure 5 and Figure 6 It is shown in the one orientation drawing and the other orientation drawing of the staggered light bar of the application that eliminates the firefly phenomenon. The LED light source is a Lambertian light source, and the light intensity distribution satisfies:

[0069] I = I0 COS θ

[0070] Wherein, I0 is the light intensity of the central optical axis, and θ is the included angle between the central optical axis and the light source exit light. Because when θ increases, the light intensity of the light source exit light decreases, when θ increases to a certain range, such as ≥ 70°, the light intensity at this time is very low, so it does not affect the overall light intensity, and the exit light intensity distribution of < 70° can be preferentially designed. This part of light (≥ 70° exit light) is reflected in the final reflecting cavity and finally enters the light guide plate.

[0071] Here, the thickness of the light guide plate 104 is selected as 2mm, as shown in Figure 6 In order to make the light directly emitted by the LED light fall into the right-angled triangle reflecting platform, the distance between the first light bar 101 and the second light bar 201 is set as z. Through the relationship between the Lambertian light source direct light and the direct distance and the sine theorem, the following formula is obtained:

[0072] S △ = S LED + 2 * x

[0073] x / sin θ = z / sin (90°- θ)

[0074] Wherein, S is the maximum angle of the light, which can be approximated as the angle between the central axis and the light source, here we take θ = 70 °; x is the distance between the right end of a LED light in the first light bar and the left end of a LED light in the second light bar; z is the distance between the first light bar and the second light bar; S LED is the length of the LED light of the first light bar and the second light bar. △ is the length of the right triangle reflecting platform.

[0075] Further, from Figure 5 and Figure 6 It can be known that the first light bar 101 and the second light bar 201 are staggered designed, and the light source range of the LED light 1011 of the first light bar 101 can be just able to fall on the right triangle reflecting platform 2012 of the second light bar 201; similarly, the light source range of the LED light 2011 of the second light bar 201 can be just able to fall on the right triangle reflecting platform 1012 of the first light bar 101, so that the light can be fully reflected and utilized, and this design can well compensate the firefly phenomenon caused by the direct incidence of the single light bar into the light receiving surface of the light guide plate 104. More preferably, the center distance between the LED light 1011 of the first light bar 101 and the LED light 2011 of the second light bar 201 can be between 20-21mm, and the distance between the first light bar 101 and the second light bar 201 can be between 2-3mm.

[0076] Please refer to Figure 7 , Figure 8 and Figure 9 , which are the middle cross-sectional view and the other two orientation views of the staggered light bar backlight module for eliminating the firefly phenomenon. It includes the first light bar 101, the second light bar 201, the substrate 102, the reflecting sheet 103, the light guide plate 104, the diffusion sheet 105, the light enhancement sheet 106, the module edge layer 107, the heat dissipation metal plate 108, the edge light shielding film 109, the hollow triangle heat dissipation area 110, and the light propagation cavity 111. Wherein the light bar is Figure 5 and Figure 6The substrate 102 is arranged in staggered manner, preferably, the thickness of the substrate 102 is between 1.5-2.5mm, and the substrate 102 can be one of a metal substrate, a ceramic substrate or a glass substrate; the thickness of the light guide plate 104 is between 1.2-2.0mm, and the shape of the light guide plate 104 includes one of a flat plate, a T shape and a combination thereof, and the material of the light guide plate 104 can be one of polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS) or glass; the edge width of the module edge layer 107 is between 1.0-2.0mm, and the material of the module edge layer 107 can be one of black rubber, plastic material or composite material, the module edge layer 107 tightly adheres the diaphragm and the light guide plate to prevent light leakage; the heat dissipation metal plate 108 covers the entire light source generating area, and the material of the heat dissipation metal plate 108 can be one of aluminum, copper or aluminum alloy, the high-thermal-conductivity material enables efficient heat dissipation, and the heat dissipation metal plate 108 also serves as a function of loading and receiving the LED light bar; the hollow triangular heat dissipation area 110 is a difference set part of the rectangular light source generating area and the light propagation cavity, and the middle of the hollow triangular heat dissipation area 110 is supported by a thin sheet of ceramic or metal material, and the whole is one of ceramic or metal material, due to the hollow design and the high-thermal-conductivity material, the heat dissipation of the LED light source is greatly enhanced.

[0077] Further, please refer to Figure 10 , which is an embodiment of the light propagation cavity in the backlight module of the staggered light bar for eliminating the firefly phenomenon. Because the light propagation cavity 111 is designed in symmetrical manner up and down, the LED light of the lower part is selected for design analysis, and the LED lights of the second light bar 201 are divided into left and right parts for analysis.

[0078] As shown in Figure 10 , the positions between the two LED light bars and the light guide plate are preliminarily determined, the distance between the light emitting surface of the LED light and the lower edge of the light guide plate 104, i.e. the vertical distance from A to the LED light, is about 0.4mm, the horizontal distance between the LED light bar and the light guide plate, i.e. the horizontal distance S AB , is about 1mm, and a certain light reflection space is reserved.

[0079] In order to more clearly show the rationality of the size design of the staggered light bar and the light propagation cavity for eliminating the firefly phenomenon, please refer to Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 and Figure 19 , which are the light propagation path diagram and other light propagation path diagrams of the light propagation cavity in the backlight module of the staggered light bar for eliminating the firefly phenomenon.

[0080] First, the cross-sectional shape of the light propagation cavity is a rectangle minus the three triangles corresponding to the three hollow triangular heat dissipation areas. Taking the lower left vertex of the cross-sectional shape of the light propagation cavity and the cross-sectional shape of the light guide plate (i.e., the rectangle) as point A, and proceeding counter-clockwise, we can obtain the vertices B, C, D, E, F, G, H, and I of the cross-sectional shape of the light propagation cavity; let A' be the light-incident critical point at the lower edge of the light-incident side of the light guide plate. For example... Figure 11 , 12 As shown in Figures 13 and 14, we will first discuss the light propagation path of the left half. To ensure that all outgoing light rays (≥70°) fall into the light-incident side of the light guide plate 104, and to reserve sufficient space for light reflection, we first set the vertical reflection structure S. CD If the value is 1mm, then S can be derived. DE The vertical distance is 1mm, at which point, if... Figure 11 As shown, large-angle light rays pass through the vertical reflection structure S CD The light is reflected to the light-incident side of the light guide plate 104. According to the law of reflection, when the light from the left half passes through point D and the upper structure, the light angle (>70°) is due to most of the large-angle light rays already reflected from the vertical reflection structure S. CD The light is reflected to the light-incident side of the light guide plate 104 (calculated at 30°). Since all light rays are considered to be incident, a critical ray is set to enter the portion above the lower edge of the light-incident side of the light guide plate 104. Because S... AD The horizontal distance is approximately 2.5mm. Therefore, we can assume the critical ray reaches the lower edge A' of the light guide plate at approximately 0.1mm. By the Pythagorean theorem, ∠A'DA is approximately 4°. Drawing vertical auxiliary lines from points D and D' (the critical point of light output from the light strip), and a horizontal auxiliary line from point E, we obtain the following relationship:

[0081] ∠ODE + ∠EDA' + ∠A'DA = 90°

[0082] ∠EDA'+∠A'DA+∠ADD”=90°

[0083] ∠ODE + ∠ADD” + ∠CDD' = 90°

[0084] ∠ADD”=∠D'DD”

[0085] Where ∠D'DD” and ∠ADD” are the incident angle and the exit angle, respectively, and ∠CDD'=30°, we find that ∠ODE is approximately 30°. Then, by the Pythagorean theorem, we can find the hypotenuse S of the right triangle. DE With a thickness of approximately 1.15mm, the structural parameters of the hollow triangular heat dissipation area can be obtained as follows: S FD Approximately 2mm, S OE Approximately 0.7mm, S CDThe diameter is approximately 0.7 mm, and ∠ODE is approximately 30°. The light propagation path at this point is as follows: Figure 12 As shown.

[0086] Because the light propagation cavity 111 is symmetrical vertically, its general structure is already determined. Next, the propagation paths of the remaining light rays (0–30°) in the left half are verified, ensuring that all light rays are reflected to the light-incident side of the light guide plate 104. The light propagation path at this point is as follows: Figure 13 and Figure 14 As shown, according to the law of reflection, the requirements are met. More preferably, the dimensions of the light propagation cavity 111 are as follows: the longitudinal distance S between the light guide plate 104 and the first lamp strip 101 is... AB' The lateral distance S between the light guide plate 104 and the right end of the first light strip 104 is between 1.0-1.1mm. BB' The distance S between the lateral end of the light guide plate 104 and the light propagation cavity 111 is between 0.9-1.0 mm. CB' Between 2.4-2.5mm, with a hollow triangular area in the middle and a bottom S of 110. FD Between 2.0-2.1mm, high S OE The angle between 0.6-0.7mm, ∠ODE between 28°-32°, and the angle ∠ABH between the right end of the light guide plate 104 and the first light strip 101 between 42°-47° are all within the range of 0.6-0.7mm.

[0087] like Figure 15 , Figure 16 , Figure 17 , Figure 18 and Figure 19 As shown, let's discuss the light propagation path of the right half. Let point H' be the endpoint corresponding to the height of the right-angled triangular reflector of the first LED strip, point H" be the endpoint where the LED center light reaches the right-angled triangular reflector of the first LED strip, and point E' be the center endpoint of the light guide plate on the light-incident side. The angle bisector of ∠EH"E' intersects the line EE' at point E". Since the structure of the light propagation cavity 111 is roughly determined, when determining the propagation of the light in the right half, when the outgoing light passes through the reflection structure HH' of the right-angled triangular reflector, we can assume that the light is just reflected to the center point E' of the light guide plate on the light-incident side. Figure 15 As shown, draw a horizontal auxiliary line at point E. At this point, the critical value of the outgoing ray just passes through EH” and intersects at point H”. Let S be... EH” Approximately 1.8mm, actual measured S EE” Given a value of 0.5mm, and considering the similarity between △HGH' and △H”EE” (where point E” is the intersection of EE' and H”E”), the following relationship holds:

[0088] S HG / S GH' =S H”E / SEE”

[0089] Known S HG = 1.5mm, then the S GH' = 0.42mm, the structure parameters of the right triangle reflecting table can be determined as: S HG = 1.5mm, S GH' = 0.42mm, the light propagation path is shown in Figure 15 .

[0090] Because the structure parameters of the light propagation cavity 111 and the right triangle reflecting table are determined, the propagation path of the right half light is verified again, so that all the light can be reflected to the light-in side of the light guide plate 104, the light propagation path is shown in Figure 16 , Figure 17 , Figure 18 and Figure 19 , which meets the requirements according to the reflection law. More preferably, the specifications of the right triangle reflecting table 1012(2012) are as follows: the length S △ of the right triangle reflecting table 1012(2012) is between 18-19mm, the width S HG of the right triangle reflecting table 1012(2012) is between 1.5-1.6mm, and the height S GH' of the right triangle reflecting table 1012(2012) is between 0.4-0.5mm.

[0091] The staggered lamp bar design, the LED lamp bars are oppositely arranged, the direct LED range just falls on the reflecting right triangle reflecting table, then the light is finally reflected to the light-in side of the light guide plate through the angle design of the reflecting right triangle reflecting table and the light propagation cavity, the LED light source is reserved a certain distance from the light-in side of the light guide plate, so that the light can be fully dispersed, and finally the firefly phenomenon is eliminated.

[0092] Please refer to Figure 20 , which is another embodiment of the light propagation cavity in the staggered lamp bar backlight module for eliminating the firefly phenomenon. Figure 10The light propagation design method is as follows: first, the cross-sectional shape of the light propagation cavity is a rectangle PK"K'N minus two triangles △MLK' and △KLK" in the lower left and right parts, the cross-sectional shape of the light propagation cavity and the cross-sectional shape of the light guide plate are a rectangle with the left lower vertex as point J, and the vertices K, L, M, N, and P of the cross-sectional shape of the light propagation cavity are obtained in anticlockwise order, point K' is the intersection of the extension line of straight line NM and the horizontal extension line of point L, point K" is the intersection of the extension line of straight line JK and the horizontal extension line of point L, point M' is the wide end point of the right-angled triangular reflecting platform, and point M" is the high end point of the right-angled triangular reflecting platform, the light propagation cavity 111 includes a third lamp strip 301 of a direct light source and a fourth lamp strip 401 having a certain angle with the third lamp strip 301, and the third lamp strip 301 is provided with a right-angled triangular reflecting platform 3012, the base length of the right-angled triangular reflecting platform 3012 of the third lamp strip 301 is between 6.0-7.0 mm, the height is between 0.5-0.7 mm, the base width is between 1.2-1.4 mm, the base covers a part of the longitudinal lamp strip 301, and the fourth lamp strip 401 is not provided with a right-angled triangular reflecting platform. More preferably, the specification size of the light propagation cavity 111 is as shown in the figure, which is respectively: S NP between 2.5-2.6 mm, S M'K' between 1.3-1.4 mm, S K'L between 1.2-1.3 mm, S MK' between 0.6-0.7 mm, ∠KLK" is between 42°-47°, and ∠MLK' is between 30°-35°.

[0093] In order to more clearly show the rationality of the staggered lamp strip and the size design of the light propagation cavity for eliminating the firefly phenomenon, please refer to Figure 21 , Figure 22 , Figure 23 , Figure 24 , Figure 25 and Figure 26 , which show another embodiment of a light propagation path diagram and other light propagation path diagrams of a backlight module with staggered lamp strips for eliminating the firefly phenomenon. As shown in Figure 21 , Figure 22 and Figure 23 , the upper part of the light source of the third lamp strip 301 is reflected into the light entrance side of the light guide plate 104, the lower part is directly injected into the light entrance side of the light guide plate 104, and the lower light source critical part is just all injected into the light entrance side of the light guide plate 104, which is independent of the fourth lamp strip 401. As shown in Figure 24 , Figure 25 and Figure 26As shown, the light source of the fourth light bar 401 reflects light into the light entrance side of the light guide plate 104 through the reflection structure of the reflection cavity, and the left critical part of the light source is just at the connection point M of the reflection structure, and the right critical part of the light source is just at the vertex of the right-angled triangular reflection platform 3012 of the third light bar 301.

[0094] The arrangement mode of the right-angled triangular reflection platform and the LED lamp in the third light bar is the same as that of the first light bar and the second light bar, except that the parameters of the right-angled triangular platform (length, width and height) are different. The fourth light bar does not need the right-angled triangular reflection platform because the LED in the third light bar has already directly entered the light guide plate. However, the third light bar and the fourth light bar still satisfy the staggered distribution of the LED.

[0095] In order to guarantee efficient use of light, the inner side of the light propagation cavity 111, the exposed part of the LED light bar and the rest of the periphery of the light guide plate 104 except the light entrance side are all attached with reflective film, and the connection part of the light propagation cavity 111 and the light guide plate 104 is attached with the edge covering light shielding film 109 to prevent light leakage; the optical film, the light guide plate and the reflective film are tightly attached, and the rest of the periphery of the light guide plate 104 except the light entrance side is provided with the module edge covering layer 107, which enhances the utilization rate of light and prevents light leakage.

[0096] It should be noted that, for the fully described present application, there can be various transformed, modified embodiments, not limited to the specific modes of the above-described embodiments. The above-described embodiments are only a description of the present application, not a limitation of the application. In general, the protection scope of the present application should include those transformations, substitutions and modifications that are obvious to those skilled in the art.

Claims

1. A staggered light bar to eliminate the firefly phenomenon, characterized in that, The first light bar comprises a right-angled triangular reflector and LED lamps arranged regularly and closely to the right-angled triangular reflector, the second light bar comprises a right-angled triangular reflector and LED lamps arranged regularly and closely to the right-angled triangular reflector, and the light source range of the LED lamps of the first light bar can fall on the long side of the right-angled triangular reflector of the second light bar, and the light source range of the LED lamps of the second light bar can fall on the long side of the right-angled triangular reflector of the first light bar. S △ = S LED + 2*x The right-angled triangular reflector has the following relationship according to the relationship between Lambert light and the distance of direct reflection and the reflection law: Wherein, θ is the maximum angle of the outgoing light; x is the distance between the right end of a LED lamp in the first lamp strip and the left end of a LED lamp in the nearest second lamp strip; z is the distance between the first lamp strip and the second lamp strip; S LED is the length of the LED lamp of the first lamp strip and the second lamp strip. △ is the length of the right triangle reflecting platform.

2. A backlight module using the staggered light bar to eliminate the firefly phenomenon as claimed in claim 1, characterized in that, x / sinθ = z / sin(90°-θ) 3. The backlight module of claim 2, wherein, The backlight module further comprises a substrate, a reflective sheet, a light guide plate, a diffusion sheet, a light enhancement sheet and a light propagation cavity for realizing light propagation.

4. The backlight module of claim 3, wherein, The light propagation cavity is symmetrically designed, the light emitting surface of the first light bar and the second light bar is perpendicular to the light incident side of the light guide plate, and the light propagation cavity is provided with three hollow triangular heat dissipation regions, the angle of the hollow triangular heat dissipation region and the angle of the right-angled triangular reflector can make the light of the LED lamps reflected to the light incident side of the light guide plate through the light propagation cavity, and the light source and the light incident side of the light guide plate have a predetermined light propagation distance. The light propagation cavity has the following relationship according to the geometric optics and the reflection law: The cross-sectional shape of the light propagation cavity is a shape formed by subtracting three triangles corresponding to the three hollow triangular heat dissipation regions from a rectangle, the left lower vertex of the cross-sectional shape of the light propagation cavity and the cross-sectional shape of the light guide plate, i.e. a rectangle, is taken as point A, and the vertices B, C, D, E, F, G, H and I of the cross-sectional shape of the light propagation cavity can be obtained in anticlockwise order, wherein A and D are of the same height, F and I are of the same height, the LED lamps of the first light bar and the second light bar are located in the cross-sectional shape of the light propagation cavity which is a rectangle, B and H are respectively one vertex of the two LED lamps, and one side of the two LED lamps is respectively a segment of BC and HG; A' is the lower light incident critical point of the light incident side of the light guide plate, D' is the light emitting critical point of the left end of the LED lamps of the first light bar, OD is perpendicular to OE and intersects at point O, DD" is perpendicular to DE and intersects at D" point on the LED lamps of the first light bar, and ∠ODE + ∠EDA' + ∠A'DA = 90° ∠EDA' + ∠A'DA + ∠ADD" = 90° ∠ODE + ∠ADD" + ∠CDD' = 90° ∠ADD" = ∠D'DD" 5. The backlight module of claim 4, wherein, The light ray propagation cavity, make BB' AB' intersect at point B', then the light guide plate distance the first lamp bar LED lamp longitudinal distance S AB' Between 1.0-1.1mm, the light guide plate distance the first lamp bar LED lamp right end of the transverse distance S BB' Between 0.9-1.0mm, the light guide plate distance the light ray propagation cavity transverse end distance S CB' Between 2.4-2.5mm, the middle of the hollow triangular heat dissipation area base length S FD Between 2.0-2.1mm, high S OE Between 0.6-0.7mm, ∠ODE between 28°-32°, the light guide plate and the first lamp bar right end of the LED lamp angle ∠ABH between 42°-47°.

6. The backlight module of claim 4, wherein, Wherein, ∠D'DD" and ∠ADD" are the incident angle and the exit angle respectively, and ∠ODE, ∠EDA', ∠A'DA and ∠CDD' are the structural parameters of the light propagation cavity. Suppose that the central outgoing light of the LED lamps of the first light bar is reflected to the center point E' of the light incident side of the light guide plate through the reflection structure, i.e. the hypotenuse HH', of the right-angled triangular reflector of the second light bar, the corresponding normal line E"H" of HH' intersects HH' at point H", and EE' at point E", and there is the following relationship between the similar triangles HGH' and H"EE": S HG / S GH' = S H”E / S EE” wherein, AHGH', AH"EE", the width S of the right triangle reflecting platform HG , the height S of the right triangle reflecting platform GH' , the distance S between the point H" and E H”E and the distance S between the points E and E" EE” are the structural parameters of the light ray propagation cavity.

7. The backlight module of claim 6, wherein, the length S of the right triangle reflecting table △ between 18-19 mm, the width S of the right triangle reflecting table HG between 1.5-1.6 mm, the height S of the right triangle reflecting table GH' between 0.4-0.5 mm.

8. An interleaved light bar to eliminate the firefly phenomenon, characterized in that, The third light bar including direct light source and the fourth light bar with a predetermined angle with the third light bar, and the third light bar is provided with a right triangle reflection platform, the LED light in the third light bar is arranged closely with the right triangle reflection platform, the LED light in the fourth light bar is arranged relative to the right triangle reflection platform in the third light bar, the light rays of the upper part of the light source of the third light bar are reflected into the light entrance side of the light guide plate, the light rays of the lower part of the light source of the third light bar are directly injected into the light entrance side of the light guide plate, and the critical part of the light rays of the lower part of the light source of the third light bar is just incident on the critical point of the light entrance side of the light guide plate; the light rays of the light source of the fourth light bar are reflected into the light entrance side of the light guide plate through the right triangle reflection platform of the third light bar, and the critical part of the light rays of the left part of the light source of the fourth light bar is just at the critical point M of the reflection structure of the light ray propagation cavity, the critical part of the light rays of the right part of the light source of the fourth light bar is just at the vertex of the right triangle reflection platform of the third light bar, and finally all the light rays are incident or reflected to the light entrance side of the light guide plate of the backlight module.

9. A backlight module using the staggered light bar to eliminate the firefly phenomenon as claimed in claim 8, characterized in that, It also includes a substrate, a reflection sheet, a light guide plate, a diffusion sheet, a light enhancement sheet and a light ray propagation cavity for realizing light ray propagation arranged in sequence from bottom to top.

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