Slim type back light unit

Abstract

The present invention relates to a slim backlight unit for implementing an ultra-slim display with mini LEDs, and more specifically, to a slim backlight unit comprising: a substrate on which a plurality of point light sources are mounted; a reflector coupled to the upper part of the substrate and having through holes formed corresponding to the positions of each of the point light sources so that light emitted from each of the point light sources is irradiated in an upward direction; and a transparent resin that surrounds the point light sources and is coupled inside the through holes to diffuse the light emitted from the point light sources.

Description

Technology Field

[0001] The present invention relates to a slim backlight unit, and more particularly to a slim backlight unit for implementing an ultra-slim display using mini-LEDs. Background Technology

[0002] FIG. 1 is a perspective view of a square reflective cup matrix and a reflective cup according to the same, as described in Registration No. 10-0985956, and FIG. 2 is a drawing of a reflector plate as described in Application No. 10-2019-7026620.

[0003] The prior art introduced in Fig. 1 introduces a reflector structure configured by arranging multiple reflective shapes, each having a symmetrical shape having a circular, elliptical, or parabolic shape, with a hole formed for applying an LED on the focal plane, and configuring the reflector structure so that light emitted from the LED forms a uniform light source across the entire opening (upper side) of the reflector.

[0004] However, since this structure is formed with a rotationally symmetrical reflector shape, it imposes limitations on securing light uniformity when the left and right spacing of the LEDs is different, and the strong light from the front of the LEDs cannot be dispersed, which limits the reduction of product thickness.

[0005] In addition, when forming a surface light source using a reflector, maximizing the reflector's function by maximizing the area of ​​light emitted from the source requires increasing the height of the reflector and the number of light sources (reducing the spacing between light sources), which leads to issues of increased product thickness and rising costs.

[0006] Meanwhile, the prior art introduced in FIG. 2 introduces a reflector structure for increasing contrast ratio by arranging multiple reflective shapes in which holes for applying LEDs are formed on the lower surface of a reflector having a side slope, changing the light path emitted from the side of the LED to the reflector to form a surface light source with a uniform distribution, and minimizing light leakage to the light source group.

[0007] However, since this structure concentrates only the light emitted from the sides of the LED to create a uniform surface light source, it cannot disperse the strong light emitted from the front of the LED, which limits the reduction of the product thickness. Prior art literature

[0008] (0001) Korean Registered Patent No. 10-0985956 (0002) Korean Patent Application No. 10-2019-7026620 The problem to be solved

[0009] The technical problem that the present invention aims to solve is to provide a slim backlight unit that can be applied to realize an ultra-slim display using Mini LEDs.

[0010] Another technical problem that the present invention aims to solve is to provide a slim backlight unit capable of reducing the number of light sources and the thickness of the product by forming an intaglio dispersion pattern on the top of a transparent resin surrounding a point light source, thereby increasing the light transmission capability due to the dispersion effect of emitted light in the front (normal) direction caused by the internal total reflection effect resulting from the formation of an air layer, the light-guiding effect of the transparent resin itself, and uniform light emission by an independent square-shaped aspherical reflector.

[0011] Another technical problem that the present invention aims to solve is to provide a slim backlight unit capable of increasing the contrast ratio by having a reflector block light guided between each group (Block) of point light sources.

[0012] Another technical problem that the present invention aims to solve is to provide a slim backlight unit capable of increasing brightness by increasing the light extraction (out-coupling) efficiency within the light source through the reduction of the difference in refractive index caused by a transparent resin around the point light source, and by preventing light loss resulting from the application of additional components to disperse strong light at the front of the light source. means of solving the problem

[0013] The slim backlight unit of the present invention for achieving the above technical problem comprises: a substrate on which a plurality of point light sources are mounted; a reflector coupled to the upper part of the substrate and having through holes formed corresponding to the positions of each of the point light sources so that light emitted from each of the point light sources is irradiated in an upward direction; and a transparent resin that surrounds the point light sources and is coupled inside the through holes to diffuse the light emitted from the point light sources.

[0014] In addition, the inner surface of the through hole has a square aspherical shape and is characterized by reflecting light emitted from the point light source.

[0015] In addition, the vertical height of the inner surface of the through hole (P y2 ) is, 0.2㎜ ≤ P y2 It is characterized by being composed of ≤ 1.0 mm.

[0016] In addition, the straight distance (P) from the center of the point light source to the lower inner surface of the through hole x0 ) is, '(0.3×S / 2) ≤ P x0 It is formed by the relationship '≤ (0.6×S / 2), where S = distance between the centers of adjacent point light sources', and the straight distance (P) from the center of the point light source to the upper inner surface of the through hole. x2 ) is, 'P x2 = G / 2, where G = the distance between adjacent through holes, is formed by the relationship, and the aspherical shape of the inner surface of the through hole is 'B x,y (t) = (1-t) 2 P x0,y0 + 2t(1-t)P x1,y1 + t 2 P x2,y2 , at this time, formed by the Bezier curve formula for t∈[0,1]', where 'P x0 ≤ P x1 ≤ (P x2 × 0.5), (P y2 × 0.2)≤ P y1 ≤ (P y2× 0.8), at this time P y2 = Characterized by being formed under the condition of the height of the above-mentioned reflector.

[0017] In addition, the upper surface of the transparent resin is characterized by having an intaglio dispersion pattern formed thereon to disperse light emitted from the point light source.

[0018] In addition, the above point light source is, (S H ) ≤ (0.4 × P y2 ) and (S W ) ≤ 0.5㎜ (here, S H = Height of the above point light source, P y2 = Height of the above reflector, S W = Characterized by being configured with the condition of the width of the above-mentioned intaglio dispersion pattern.

[0019] In addition, the above-mentioned intaglio dispersion pattern is W ≤ (0.1×S) and D ≥ (0.4×P y2 ) (where W = width of the intaglio dispersion pattern, S = distance between the centers of adjacent point light sources, D = depth of the intaglio dispersion pattern, P y2 = Characterized by being configured under the condition of the height of the above reflector.

[0020] In addition, the shape of the above-mentioned intaglio dispersion pattern is characterized by being composed of any one of the shapes of a cone, a pyramid, a double-angled cone, a curved cone, or a curved pyramid.

[0021] In addition, the transparent resin is characterized by being composed of a highly transparent material including at least one of Si, Siox, Epoxy, Al, PP, PMMA, PC, PI, ZnO, PUA, Glass, Sapphire, and EVA.

[0022] In addition, a fixing projection is formed on the lower part of the reflector, and a fixing groove is formed on the substrate corresponding to the fixing projection.

[0023] In addition, the reflector is characterized by having at least one of a specular reflection function and a diffuse reflection (diffuse) function, and being composed of a high-reflection material with a total reflectivity of 80% or more.

[0024] In addition, the upper portion of the above-mentioned intaglio dispersion pattern is characterized by including an optical sheet portion composed of at least one sheet for increasing uniformity and brightness.

[0025] In addition, the optical sheet portion is characterized by including a color conversion sheet that changes blue light into white light when a blue point light source is applied.

[0026] In addition, the red and green fluorescent materials of the color conversion sheet are characterized by being composed of at least one of β-Sialon, Silicates, Sulfides, Oxynitrides, Nitrides, KSF, Quantum Dot, and organic phosphors. Effects of the invention

[0027] The present invention described above has the following effects.

[0028] First, a substrate having a point light source mounted thereon is positioned on the lower surface of a reflector plate having a through hole formed therein, which has an independent, square-shaped aspherical reflector structure, and a transparent resin is formed to surround and fill the point light source inside the through hole, and a dispersion pattern that disperses light is formed on the upper surface of the transparent resin, thereby improving the light dispersion distance (light transmission capability) through the dispersion of strong light at the front of the light source and the light-guiding effect of the transparent resin.

[0029] In addition, uniform light emission due to the independent square aspherical shape can reduce the number of light sources and decrease the thickness of the product.

[0030] In addition, since through holes acting as reflectors are configured independently for each point light source, the reflectors block light being guided between each group (Block) of point light sources, thereby increasing the contrast ratio.

[0031] In addition, the light extraction (out-coupling) efficiency inside the light source can be increased by reducing the difference in refractive index caused by the transparent resin around the point light source.

[0032] In addition, brightness can be increased by preventing light loss caused by the application of additional components to disperse strong light at the front of the light source. Brief explanation of the drawing

[0033] FIG. 1 is a drawing showing a perspective view of a conventional square reflective cup matrix and a reflective cup drawing according thereto. FIG. 2 is a drawing showing a conventional reflector structure, FIG. 3 is a schematic exploded perspective view according to one embodiment of the slim backlight unit of the present invention. FIG. 4 is a cross-sectional view of the connection of FIG. 3, FIG. 5 is a conceptual diagram showing the ray tracing state from a point light source according to the conventional and the present invention. FIG. 6 is a bottom perspective view showing various shapes of an intaglio dispersion pattern according to the present invention, FIG. 7 is a plan view showing the main part of a reflector according to the present invention, FIG. 8 is a plan view showing the main part of a transparent resin according to the present invention, FIG. 9 is a diagram illustrating a formula according to the present invention, FIG. 10 is a drawing illustrating the shape of a fixed projection formed on the lower part of a reflector according to the present invention. FIG. 11 is a conceptual diagram showing the combined state of a substrate and a reflector according to the present invention. FIG. 12 is a drawing showing the structure according to the present invention and the structures of Examples 1 to 3. FIG. 13 is a luminance distribution diagram for a surface light source according to each structure of FIG. 12, FIG. 14 is a drawing for showing interference (contrast ratio) between light source groups by turning off the light source in a specific area according to each structure of FIG. 12. FIG. 15 is a diagram showing the difference in light uniformity according to each structure of FIG. 12. Specific details for implementing the invention

[0034] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0035] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments of the present invention. These terms are intended only to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms. Where it is stated that a component is "connected," "combined," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but that another component may also be "connected," "combined," or "connected" between each component.

[0036] FIG. 3 is a schematic exploded perspective view according to one embodiment of a slim backlight unit of the present invention, FIG. 4 is a combined cross-sectional view of FIG. 3, FIG. 5 (a) is a conceptual diagram showing a light tracing state according to the prior art, FIG. 5 (b) is a conceptual diagram showing a light tracing state according to the present invention, FIG. 6 is a bottom perspective view showing various shapes of an intaglio dispersion pattern according to the present invention, FIG. 7 is a plan view showing a key part of a reflector according to the present invention, FIG. 8 is a plan view showing a key part of a transparent resin according to the present invention, FIG. 9 is a drawing shown to explain a formula according to the present invention, FIG. 10 is a drawing shown to show the shape of a fixing projection formed on the lower part of a reflector according to the present invention, and FIG. 11 is a conceptual diagram showing the combined state of a substrate and a reflector according to the present invention.

[0037] The slim backlight unit structure of the present invention is described below with reference to FIGS. 3 to 11. However, since the basic structure of a backlight unit (BLU: Back Light Unit) is a known form, only the characteristic structure according to the present invention, which is different from the conventional one, will be described below.

[0038] The substrate (10) according to the slim backlight unit of the present invention has a form in which a plurality of point light sources (11) are mounted at regular intervals, for example, a plurality of mini LEDs are mounted.

[0039] A reflector plate (20) is attached to the upper part of a substrate (10) to which a plurality of point light sources (11) are combined.

[0040] In the reflector (20) according to the present invention, a through hole (21) is formed corresponding to the position of each point light source (10) mounted on the substrate (10). Referring to FIGS. 4 and 7, the inner surface of the through hole (21) has a square aspherical shape, and the inner periphery of the through hole (21) acts as a reflector that reflects light emitted from the point light source (11) so that it is irradiated in an upward direction. To this end, the reflector (20) has at least one of a specular reflection function and a diffuse reflection (diffusion) function, and it is preferable to be composed of a high-reflection material having a total reflectivity of 80% or more.

[0041] Referring to FIG. 4, the transparent resin (30) is formed by surrounding the point light source (11) and being coupled inside the through hole (21). The transparent resin (30) may be composed of a highly transparent material including at least one of Si, Siox, Epoxy, Al, PP, PMMA, PC, PI, ZnO, PUA, Glass, Sapphire, and EVA.

[0042] Referring to FIG. 5 and FIG. 8 together with FIG. 4, an intaglio dispersion pattern (31) is formed on the upper surface of the transparent resin (30) to disperse light emitted from a point light source (11). The transparent resin (30) is coupled inside the through hole (21), that is, inside a reflector having an aspherical slope, and an intaglio dispersion pattern (31) is formed on the upper surface of the transparent resin (30) located vertically above the point light source (11). That is, the slim backlight unit according to the present invention has a structure that improves brightness by increasing light extraction (out-coupling) efficiency through reducing the difference in refractive index with the light source by forming the transparent resin (30), and enables the reduction of the number of light sources and the realization of an ultra-slim display product through the light dispersion function of the intaglio dispersion pattern (31) on the upper surface of the light source and the light guidance effect of the transparent resin (30).

[0043] The transparent resin (30) can be manufactured by considering processes such as transfer molding, injection molding, and a method using UV material to apply the transparent resin (30) to the through hole (21) formed in the reflector (20).

[0044] In addition, since a point light source (11) is positioned inside the reflector (20), that is, inside each through hole (21), the light emitted from the point light source (11) is reflected by the inner circumference of the through hole (21), which is the reflector, and the phenomenon of leakage to an adjacent light source area is blocked, thereby improving the contrast ratio.

[0045] Meanwhile, in order to disperse strong light from the upper surface (normal direction) of the point light source (11), total reflection occurs only when the angle of the light ray incident on the intaglio dispersion pattern (31) is greater than or equal to the critical angle (internal total reflection condition), and this is more effective when the pattern shape is formed in intaglio rather than in relief. In addition, when dispersing strong light from the upper surface of the point light source (11), it is desirable to configure the pattern shape to facilitate controlling the maximum angle at which reflection is allowed and the path of the reflected light. As shown in FIG. 6, the shape of the intaglio dispersion pattern (31) can be configured as any one of a cone, a pyramidal double-angled cone, a curved cone, and a curved pyramid.

[0046] Additionally, an optical sheet portion (40) composed of at least one sheet for increasing light uniformity and brightness may be included on the upper part of the negative dispersion pattern (31). At this time, the optical sheet portion (40) may include a color conversion sheet that changes blue light into white light when a blue point light source is applied. In this case, the red and green fluorescent materials of the color conversion sheet may be composed of at least one of β-Sialon, Silicates, Sulfides, Oxynitrides, Nitrides, KSF, Quantum Dot, and organic phosphors to increase color reproduction rate.

[0047] Next, the following length condition equation will be explained with reference to Fig. 9, together with Figs. 3 and 4.

[0048] Vertical height (P) of the inner surface of the through hole (21) y2 ) is, 0.2㎜ ≤ P y2 It is preferable to configure it to be ≤ 1.0 mm. At this time, the vertical height (P) of the inner surface of the through hole (21) y2 If ) is smaller than 0.2 mm, the reflection function due to the depth constraint of the intaglio dispersion pattern (31) caused by the height (0.1 mm) of the light source is reduced (additional reflective coating required), and the light diffusion ability due to the light guide thickness of the transparent resin (30) may be reduced. In addition, the vertical height (P) of the inner surface of the through hole (21) y2 When the thickness exceeds 1 mm, the transparent resin material also increases, so it can be implemented as a standard Mini LED molding structure, which may reduce technical competitiveness.

[0049] In addition, the straight distance (P) from the center of the point light source (11) to the lower inner surface of the through hole (21) x0 ) is, '(0.3×S / 2) ≤ P x0 ≤ (0.6×S / 2), where S = distance between the centers of two adjacent point sources.

[0050] In addition, the straight distance (P) from the center of the point light source (11) to the upper inner surface of the through hole (21) x2 ) is, 'P x2 = G / 2, where G = the distance between adjacent through holes, can be formed by this relationship.

[0051] In addition, the non-spherical shape of the inner surface of the through hole (21) is 'B x,y (t) = (1-t) 2 P x0,y0 + 2t(1-t)P x1,y1 + t 2 P x2,y2 , at this time, formed by the Bezier curve formula for t∈[0,1]', where 'P x0 ≤ P x1≤ (P x2 × 0.5), (P y2 × 0.2)≤ P y1 ≤ (P y2 × 0.8), at this time P y2 = It can be formed under the condition of the height of the above reflector.

[0052] Also, the point light source (11) is, (S H ) ≤ (0.4 × P y2 ) and (S W ) ≤ 0.5㎜ (here, S H = Height of point light source, P y2 = Height of the reflector, S W = Can be configured by the condition of the width of the negative dispersion pattern.

[0053] Additionally, the negative dispersion pattern (31) is such that W ≤ (0.1×S) and D ≥ (0.4×P y2 ) (where W = width of the intaglio dispersion pattern, S = distance between the centers of two adjacent point light sources, D = depth of the intaglio dispersion pattern, P y2 = Can be configured with the condition of the height of the reflector.

[0054] When designing by satisfying the length condition equation as described above, the aforementioned effect can be obtained.

[0055] Meanwhile, referring to FIGS. 10 and 11, a fixing projection (22) is formed on the lower part of the reflector (20), and a fixing groove (not shown in the drawing) may be formed on the substrate (10) corresponding to the fixing projection (22), although not shown in detail. That is, when the reflector (20) is attached to the upper part of the substrate (10), a local fixing projection (22) is formed on the lower surface of the reflector (20) to fasten it to the substrate (10), and additionally, if an adhesive is used, it can be firmly fixed to the substrate (10).

[0056] In the drawing, the shape of the fixing projection (22) is shown as a cylinder shape, but it is not desirable to limit the shape of the fixing projection (22) for coupling with the substrate (10) to only the shown shape as long as it is a shape that can satisfy the male and female coupling structure.

[0057] FIG. 12 is a diagram showing the structure according to the present invention and the structures of Examples 1 to 3. FIG. 12 (a) is composed of a reflective sheet, a transparent resin, and a light-blocking film. The reflective sheet and light-blocking film used are those generally used in backlight units, and the transparent resin uses the same material as the transparent resin applied in the present invention. FIG. 12 (b) is formed with the same structure as the present invention, except that the structure of the transparent resin is omitted. FIG. 12 (c) omits the light-blocking film from the structure of (a) and forms a cathode dispersion pattern on the upper surface of the transparent resin as in the present invention. FIG. 12 (d) is a structure according to the present invention.

[0058] A backlight unit was configured under the conditions described above, and as a result of conducting a simulation, the results shown in FIGS. 13 to 15 were obtained. The simulation was performed under the conditions of light source = (200 × 440 × 100) μm, light source spacing = (6.77 × 6.53) mm, and thickness of reflector (White Plastic) and transparent resin (composed of transparent silicone) = 0.4 mm.

[0059] FIG. 13 is a luminance distribution diagram for a surface light source according to each structure of FIG. 12, and FIG. 14 is a diagram showing the interference (contrast ratio) between light source groups by turning off the light source in a specific area according to each structure of FIG. 12. In addition, FIG. 15 is a diagram showing the difference in light uniformity according to each structure of FIG. 12, and the relative luminances of FIG. 13 (b) to (d) were calculated based on the luminance of FIG. 13 (a). Each of (a) to (d) corresponds to the results of FIG. 12 (a) to (d), and the results of the following [Table 1] were derived.

[0060] (a) (b) (c) (d) Relative luminance 100.0% 110.1% 104.6% 105.4% Light uniformity 59.9% 26.8% 46.4% 82.1% Contrast ratio 13.7% 2.3% 6.2% 4.1%

[0061] According to the invention and simulation results described above, a substrate with a point light source mounted thereon is positioned on the lower surface of a reflector plate having a through-hole formed therein and having an independent, square-shaped aspherical reflector structure; a transparent resin is formed to surround and fill the point light source within the through-hole; and a dispersion pattern that disperses light is formed on the upper surface of the transparent resin. By doing so, the light dispersion distance (light transmission capability) can be improved through the dispersion of strong light from the front of the light source and the light-guiding effect of the transparent resin. Furthermore, the thickness of the product can be reduced along with a reduction in the number of light sources due to uniform light emission caused by the independent, square-shaped aspherical structure. Additionally, since the through-hole acting as a reflector is configured independently for each point light source, the reflector blocks light guided between each group (Block) of point light sources, thereby increasing the contrast ratio. Moreover, the efficiency of light extraction (out-coupling) within the light source can be increased by reducing the difference in refractive index caused by the transparent resin surrounding the point light source, and light loss resulting from the application of additional components to disperse strong light from the front of the light source By preventing this, brightness can be increased.

[0062] In the foregoing, although all components constituting an embodiment of the present invention have been described as being combined or operating in combination, the present invention is not necessarily limited to such embodiments. That is, within the scope of the purpose of the present invention, all components may be selectively combined in one or more ways to operate. Furthermore, terms such as "include," "constitute," or "have" described above, unless specifically stated otherwise, mean that the relevant component may be inherent; thus, they should be interpreted as allowing for the inclusion of additional components rather than excluding other components. All terms, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains, unless otherwise defined. Terms commonly used, such as those defined in advance, should be interpreted in accordance with their meaning in the context of the relevant technology and, unless explicitly defined in the present invention, should not be interpreted in an ideal or overly formal sense.

[0063] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in this invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by such embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0064] 1 : Substrate 1-1 : Point light source 2 : Reflector 10 : Substrate 11 : Point light source 20 : Reflector 21 : Through hole 22 : Fixed protrusion 30 : Transparent resin 31 : Engraved dispersion pattern 40: Optical sheet section

Claims

Claim 1 A slim backlight unit comprising: a substrate having a plurality of point light sources mounted thereon; a reflector coupled to the upper part of the substrate, having an inner surface formed in an aspherical shape and having through holes formed corresponding to the positions of each point light source to reflect light emitted from each point light source in an upward direction; a transparent resin that surrounds the point light sources and is coupled inside the through holes to diffuse the light emitted from the point light sources, and has an intaglio dispersion pattern formed vertically above the point light sources to disperse light in a normal direction; and an optical sheet portion disposed above the intaglio dispersion pattern and composed of at least one sheet for increasing uniformity and brightness. Claim 2 delete Claim 3 In claim 1, the vertical height of the inner surface of the through hole (P y2 ) is,0.2㎜ ≤ P y2 A slim backlight unit consisting of ≤ 1.0 mm. Claim 4 In claim 1, the straight distance (P) from the center of the point light source to the lower inner surface of the through hole x0 ) is, '(0.3×S / 2) ≤ P x0 ≤ (0.6×S / 2), where S = distance between the centers of adjacent point light sources, formed by the relationship, and the straight distance (P) from the center of the point light source to the upper inner surface of the through hole. x2 ) is, 'P x2 = G / 2, where G = the distance between adjacent through holes, is formed by the relationship, and the aspherical shape of the inner surface of the through hole is 'B x,y (t) = (1-t) 2 P x0,y0 + 2t(1-t)P x1,y1 + t 2 P x2,y2 , at this time, formed by the Bezier curve formula for t∈[0,1]', where 'P x0 ≤ P x1 ≤ (P x2 × 0.5), (P y2 × 0.2)≤ P y1 ≤ (P y2 × 0.8), at this time P y2 = A slim backlight unit formed under the condition of the height of the above-mentioned reflector. Claim 5 delete Claim 6 In paragraph 1, the point light source is, (S H ) ≤ (0.4 × P y2 ) and (S W ) ≤ 0.5㎜ Here, S H = Height of the above point light source, P y2 = Height of the above reflector, S W = A slim backlight unit configured with the width condition of the above-mentioned engraved dispersion pattern. Claim 7 In claim 1, the intaglio dispersion pattern is W ≤ (0.1×S) and D ≥ (0.4×P y2 Here, W = width of the intaglio dispersion pattern, S = distance between the centers of adjacent point light sources, D = depth of the intaglio dispersion pattern, P y2 = A slim backlight unit configured with the height condition of the above-mentioned reflector. Claim 8 In claim 1, the shape of the engraved dispersion pattern is a slim backlight unit composed of any one of a cone, a pyramid, a double-angled cone, a curved cone, or a curved pyramid. Claim 9 In claim 1, the transparent resin is a slim backlight unit composed of a highly transparent material including at least one of Si, Siox, Epoxy, Al, PP, PMMA, PC, PI, ZnO, PUA, Glass, Sapphire, and EVA. Claim 10 A slim backlight unit according to claim 1, wherein a fixing projection is formed on the lower part of the reflector plate and a fixing groove is formed on the substrate corresponding to the fixing projection. Claim 11 In claim 1, the reflector has at least one of a specular reflection function and a diffuse reflection (diffuse) function, and is a slim backlight unit composed of a high-reflection material having a total reflectance of 80% or more. Claim 12 delete Claim 13 delete Claim 14 delete

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