KR101484466B1 - Direct Type surface light source device for improved Luminescence and Uniformity - Google Patents

Abstract

The present invention relates to a direct surface light source device having improved luminescence and uniformity of luminescence. An intaglio cone-shaped reflective pattern and an intaglio circular cone-shaped lens pattern are formed on the upper side and the lower side of a light guide plate on which a light diffusion pattern is formed. A reflective layer is arranged on the lower side of the light guide plate. A reflective sheet having a predetermined size is arranged on the cone-shaped reflective pattern. A light source is arranged inside the intaglio cone-shaped lens pattern. The direct surface light source device can reduce the thickness thereof and increase light luminescence and light efficiency dramatically using a small number of light sources compared to the existing direct surface light source device, by converting and emitting the light of the light source introduced to the inside of the light guide plate into a surface light source through total reflection and diffused reflection.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a direct type surface light source device having improved luminance and luminance uniformity,

[0001] The present invention relates to a direct type surface light source device having improved luminance and luminance uniformity, and more particularly, to a direct type surface light source device capable of reducing the thickness of a surface light source device while using a smaller number of light sources, To a direct-type surface light source device capable of greatly improving the surface light source device.

Today, LED (Light Emitting Diode) lighting is attracting attention as a next-generation light source because of its long lifetime and energy-efficient environment-friendly characteristics compared to general light sources. LED lighting has many advantages, but there are some problems to be solved such as heat problems, price, diffuser and power supply. Particularly, there is a disadvantage that the lifetime and the efficiency are inferior unless a heat radiation design is performed due to generation of a lot of heat. In addition, LED lighting is in the early stage of market formation, so it is difficult to supply LED lighting because it is significantly higher than existing lighting.

The surface light source device used for LED illumination is divided into a direct type and an edge type according to the position of a light source.

Here, the direct type is a method of arranging the light source on the rear surface of the light guide plate and sending light to the front side, which is advantageous in terms of brightness and color control. In the edge type, a light source is disposed on the side surface of the light guide plate, and light emitted from the light source is transmitted to the front side by using the refraction and reflection of the light guide plate. It is also cheap.

Recently, surface light source devices used in LED lighting have evolved into various types as well as direct-type and edge-type, leading technological progress.

However, in the direct light type of the surface light source device, it is difficult to form a thin backlight because a distance of a certain distance from the light guide plate to the diffusing plate is required to remove the luminescent spot generated by the LED. Since the LED is a point light source, when the LED is used as a light source of a surface light source device, a dark portion is generated between the LED and the LED, resulting in a problem that the brightness is not uniform. Therefore, if the number of LEDs is increased and the interval is shortened in order to make the brightness uniform, the number of LEDs to be used is greatly increased, which causes various problems such as increased power consumption and a large increase in manufacturing cost.

Korean Patent No. 10-1264323 (2013.05.08)

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a direct-type surface light source device capable of reducing the thickness of a surface light source device and significantly improving light luminance and light efficiency, I have to propose.

According to another aspect of the present invention, there is provided a direct-type surface light source device in which a concave reflection pattern of a concave shape and a conical lens pattern of a concave shape are formed on an upper surface and a lower surface of a light-

According to another aspect of the present invention, there is provided a light guide plate comprising a light guide plate having a light diffusion plate and a concave lens pattern formed on the upper and lower surfaces of the light guide plate, Device.

According to another aspect of the present invention, there is provided a light guide plate including a light guide plate having a concave reflection pattern and a concave lens pattern formed on a top surface and a bottom surface of the light guide plate, a reflective layer disposed on a lower surface of the light guide plate, And a reflective sheet is disposed on the reflective pattern at a predetermined size.

According to another aspect of the present invention, there is provided a light guide plate including a light guide plate having a concave reflection pattern and a concave lens pattern formed on a top surface and a bottom surface of the light guide plate, a reflection layer disposed on a lower surface of the light guide plate, And a reflective sheet is disposed on the pattern at a predetermined size, and the light source is disposed inside the conical lens pattern of the obtuse angle.

Another aspect of the present invention is to provide a direct-type surface light source device capable of significantly improving light luminance and light efficiency by reducing luminance unevenness caused by high luminance in a direct portion of a light source have.

The solution to the problem of the present invention is not limited to those mentioned above, and other solutions not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a direct-type surface light source device comprising: a light guide plate formed of a translucent material and having a light diffusion pattern integrally formed on a lower surface thereof; And a concave lens pattern formed on the lower surface of the light guide plate and facing the cone-shaped reflection pattern of the concave-convex pattern, and a concave lens pattern disposed on the lower surface of the light guide plate to reflect light, And a light source disposed at a predetermined interval on the upper side so as to be disposed inside the conical lens pattern of the negative oblique angle; and a light guide plate having a conical reflection pattern of a predetermined size As shown in Fig.

Here, the light of the light source is transmitted and refracted through the conical lens pattern of the intaglio angle with the conical reflection pattern of the intaglio, and is totally reflected into the light guide plate through the conical reflection pattern of the intaglio angle and the reflective sheet, The light is totally reflected and diffused to the inside of the light guide plate by the pattern, and is reflected by the reflective layer to be emitted from the surface.

And, the reflective layer may be composed of a sticky or adhesive sheet, and the reflective sheet may be composed of a sticky or adhesive sheet.

In addition, the concave reflection pattern of the concave shape has a conical shape, and both sides between the vertexes of the cone form an arc, and the conical lens pattern of the concave shape has a conical shape, And the conical reflection pattern of the engraved angle and the conical lens pattern of the engraved angle may be regularly or irregularly arranged.

Also, the light diffusion pattern may have any one of a cone shape, a triangle shape, and a tetragonal shape arranged at predetermined intervals, or may be formed of at least one of a vertical pattern, a horizontal pattern, a diagonal pattern, a wavy pattern and a checkerboard pattern.

In addition, the light source may be composed of LEDs formed by combining one or more of white, red, orange, yellow, green, blue, indigo, or purple.

According to the present invention, a concave lens pattern of a concave reflection pattern and a concave lens pattern of a concave shape are formed on the upper and lower surfaces of a light guide plate having a light diffusion pattern, a reflection layer is disposed on the lower surface of the light guide plate, And the light source is disposed inside the conical lens pattern of the concave lens so that the light of the light source incident into the light guide plate is converted into a planar light source by total reflection and diffusive reflection and emitted, It is possible to reduce the thickness and greatly improve the light luminance and the light efficiency.

In addition, since the light incident into the light guide plate is scattered with a uniform luminance and a large area, the light is converted into a planar light source, and uniformly dispersed and emitted in a forward direction. Thus, a high quality light guide plate and a high- A uniform light intensity can be realized while using a light source.

In addition, since the distance between the front signboard or the diffusion plate and the light guide plate can be greatly reduced, the thickness of the display device, the signboard, or the billboard can be greatly reduced.

In addition, it is possible to provide a high-quality surface light source device by uniformly diffusing and emitting light from a light source to irradiate light of a uniform brightness over a wide area.

In addition, since the light incident into the light guide plate is transmitted and scattered everywhere by the optical pattern, a partial contrast difference does not occur in the plane light source, thereby improving the quality of displayed information.

In addition, it is possible to greatly reduce the number of light sources and to reduce the brightness attenuation at the interface, thereby greatly improving the brightness of the plane light source to be emitted.

Further, by forming the light guide plate integrally formed with the light diffusion pattern, the concave reflection pattern of the obtuse angle, and the conical lens pattern of the obtuse angle in one step by using the injection mold or the extrusion mold, the production time can be shortened and the manufacturing process can be simplified And it has an industrial use effect that facilitates mass production by reducing defective rate.

In addition, there is an effect that an optical pattern of various patterns of the light guide plate can be accurately formed by using a metal mold.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 to 13 are views showing a direct-type surface light source device according to a preferred embodiment of the present invention,
1 is a perspective view of a direct-type surface light source device,
2 is an exploded perspective view of the light guide plate and the substrate,
3 is an exploded perspective view of the direct-type surface light source device,
4 is a perspective view showing an upper part of the light guide plate,
5 is a perspective view showing a lower part of the light guide plate,
6 is a perspective view showing a top view of a light guide plate with a reflection sheet,
FIGS. 7 to 11 are cross-sectional views illustrating a manufacturing process of the direct-type surface light source device,
12 to 13 are sectional views for explaining conical reflection patterns of a negative angle formed on the light guide plate and shape and size of a negative lens pattern.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and similar parts are denoted by similar reference numerals throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Embodiment of direct-type surface light source device 100

2 is an exploded perspective view of a light guide plate 110 and a substrate 130. FIG 3 is a cross-sectional view illustrating a direct-type surface light source device 100 5 is a perspective view showing a bottom view of the light guide plate 110 and FIG. 6 is a perspective view showing a light guide plate 110 with a reflective sheet 140 7 through 11 are process sectional views illustrating a manufacturing process of the direct-type surface light source device 100. As shown in FIG.

1 to 11, a light diffusion pattern 114 is integrally formed on the entire lower surface of the direct-type surface light source device 100 of the present invention, and conical reflection patterns 113 of intaglio angles on the upper and lower sides, A reflective layer 114 disposed on the lower surface of the light guide plate 110 to reflect light and a concave lens pattern 115 disposed below the reflective layer 114 and having a concave lens pattern 115 formed on the concave lens pattern 115. [ A substrate 130 having a light source 131 disposed at a predetermined interval on the upper side so as to be disposed inside the reflective sheet 115 and a reflective sheet 140 ).

The light guide plate 110 may be formed of a light-transmissive material, and the light diffusion pattern 114 may be integrally formed on the entire lower surface. In addition, the light guide plate 110 may be a single plate or may include one or more layers. The light guide plate 110 is a thin plate whose minimum thickness is determined by optical considerations.

The thickness of the light guide plate 110 may be determined in consideration of the size, weight, and manufacturing cost of the device in which the light guide plate 110 is installed. For example, the thickness T of the light guide plate 110 may be in the range of 1 to 20 mm, and preferably in the range of 2 to 10 mm, such as 4.5 to 5 mm. More specifically, the thickness of the light guide plate 110 may be 5 mm.

At this time, when the thickness of the light guide plate 110 is less than 4 mm, moire phenomenon may occur due to interference of light, which may affect the quality of the print screen with black stripes. When the thickness of the light guide plate 110 is 7 mm or more, the inconvenience of handling due to the large area and the light conversion efficiency are greatly reduced.

The light guide plate 110 is made of a resin such as polymethyl methacrylate (PMMA), polycarbonate (PC) or resin, which is excellent in transparency, weatherability, hardness, . The light guide plate 110 may be made of plastic such as polycarbonate or perspex.

The light guide plate 110 may have a refractive index of 1.3 or more to provide diffraction and total internal reflection of light. For example, when the light guide plate 110 is made of PMMA, the refractive index may be 1.5.

Generally, the light guide plate has no partial difference of light and darkness after being converted into a planar light source, and light scattering should be performed well inside the light guide plate to widen the effective area of the planar light source. At this time, in order for scattering to be performed well, total reflection and diffuse reflection should be performed smoothly, and the luminance should not be unnecessarily attenuated in the light emission path.

For this, in the light guide plate 110 of the present invention, a light diffusion pattern 114 is integrally formed on the entire lower surface, and a conical reflection pattern 113 of a concave shape and a conical lens pattern 115 of a concave shape are formed on the upper and lower sides And the reflective sheet 140 is disposed on the conical reflection pattern 113 of the light guide plate 110 with a predetermined size so that the light of the light source incident into the light guide plate is converted into a planar light source by total reflection and diffuse reflection, Respectively.

First, the light diffusion pattern 114 may be integrally formed with the light guide plate 110 on the entire lower surface of the light guide plate 110. The light diffusion pattern 114 may be formed by regularly or irregularly arranging one or more shapes selected from cones, triangles, and beards at predetermined intervals. Also, the light diffusion pattern 114 may be formed of at least one selected from a vertical pattern, a horizontal pattern, a diagonal pattern, a wavy pattern, and a checkerboard pattern. At this time, the light diffusion pattern 114 can be adjusted in width and interval of each pattern by a pattern, and includes both patterns or styles that are regularly or irregularly repeated.

The light diffusion pattern 114 having such a shape realizes a surface light source by scattering and diffusing the light incident on the irregular surface of the pattern with total reflection and diffusing the light into the entire interior of the light guide plate 110, .

The cone-shaped reflection pattern 113 may be formed at an obtuse angle inward from the upper surface of the light guide plate 110. At this time, the conical reflection pattern 113 of the indented angle has a conical shape, and two sides between the vertexes of the conical can be formed as arcs (refer to FIG. 7 to FIG. 11). The dimensions of the conical reflection pattern 113 of the engraved shape will be described later in detail with reference to FIG. 12 to FIG.

The conical reflection pattern 113 having such a structure has a function of reflecting the light of a light source emitted from the conical lens pattern 115 of the engraved below to the downward direction of the light guide plate 110 through two conical sides . At this time, the light which is not reflected by the conical reflection pattern 113 of the concave-convex shape but is emitted (transmitted) to the upper portion of the light guide plate 110 is reflected by the reflective sheet 140 disposed on the conical reflection pattern 113 And is reflected to the inside of the light guide plate 110.

Here, the reflective sheet 140 has a predetermined size to sufficiently cover the upper portion of the conical reflection pattern 113, and may have a predetermined shape such as a circular shape or a square shape. The reflective sheet 140 may be made of a sticky or adhesive sheet. At this time, the reflective sheet 140 may be formed such that the surface of the reflective sheet 140 adhered to the upper surface of the light guide plate 110 reflects light.

The light emitted from the light source 131 is concentrated on the upper portion of the light source 131 and the brightness is uneven. However, in the case of the direct-type surface light source device, By arranging the reflective sheet 140 and reflecting light directly emitted from the light source 131 to the inside of the light guide plate 110, a uniformity of brightness and brightness can be further improved by implementing a surface light source.

The concave lens pattern 115 may be formed at an obtuse angle inward from a lower surface of the light guide plate 110. [ Here, the conical lens pattern 115 of the concave-convex shape has a conical shape and consists of a straight line (115a in FIG. 13) and an arc (115b in FIG. 13) having two sides each having a predetermined length between the vertexes of the cone 7 to 11). The dimensions of the intaglio conical lens pattern 115 will be described later in detail with reference to FIGS. 12 to 13.

The conical lens pattern 115 having such a structure serves to transmit, refract, and diffuse the light emitted from the lower light source 131 to the inside of the light guide plate 110 through the two conical sides. That is, in the portion (115a in FIG. 13) where the sides are linearly formed at two sides between the vertexes of the conical lens pattern 115, the light of the light source 131 is incident on the conical lens pattern 115 And the light of the light source 131 is refracted and diffused into the light guide plate 110 at a part of the circular arc (115b in FIG. 13).

The light diffusion pattern 114 formed on the light guide plate 110, the conical reflection pattern 113 and the intaglio lens pattern 115 may be integrally formed when the light guide plate 110 is formed.

For example, the light guide plate 110 may inject a liquid material through an injection mold to form a light guide plate 110 having a fine pattern. That is, the light guide plate 110 having a minute pattern such as the light diffusion pattern 114, the concave reflection pattern 113 of the concave angle, and the lens pattern 115 of the concave angle can be formed through the injection mold. At this time, the light diffusion pattern 114, the concave reflection pattern 113, and the concave reflection lens pattern 115 formed on the light guide plate 110 may be formed by optical design.

Here, the injection mold is an apparatus for forming an outer shape of an object to be formed into a depressed shape, which is molded by an embossed object because it is heated, injected with a liquid material, cooled, and taken out.

Next, a reflective layer 120, which reflects light, may be disposed on the lower surface of the light guide plate 110. The reflective layer 120 reflects light to the upper surface of the light guide plate 110 so that the surface light source converted by the light diffusion pattern 114 can not be emitted to the lower surface of the light guide plate 110.

The reflective layer 120 is disposed on the lower surface of the light guide plate 110 and reflects light and has holes at positions opposite to the conical lens pattern 115 of the intaglio angle so as to expose the conical lens pattern 115 Respectively.

The reflective layer 120 may be in the form of a sticky or adhesive sheet having a light reflecting material formed on one surface thereof. At this time, if the reflective layer 120 is formed in the form of a sticky or adhesive sheet, it may be attached to the lower surface of the light guide plate 110 on which the light diffusion pattern 114 is formed.

In addition, the reflective layer 120 may be formed using a material that reflects light. For example, the reflective layer 120 may be formed of an aluminum (Al) thin plate, and may be formed of a flat or optical pattern. The reflective layer 120 may adhere closely to the lower surface of the light guide plate 110.

If an optical pattern is formed on the reflective layer 120, the light diffusion pattern formed on the lower surface of the light guide plate 110 may be the same or different from the light diffusion pattern formed on the lower surface of the light guide plate 110.

Subsequently, a substrate 130 including a light source 131 may be disposed under the reflective layer 120. The light sources 131 may be disposed on the upper side of the substrate 130 at predetermined intervals so as to be disposed inside the conical lens pattern 115 of the negative oblique angle. At this time, the number of the light sources 131 is equal to the number of the conical reflection pattern 113 of the intaglio and the number of the conical lens patterns 115 of the intaglio angle. The position where the light source 131 is disposed may be opposite to the position where the concave lens pattern 115 is formed. Accordingly, the light sources 131 may be regularly or irregularly arranged according to the arrangement of the conical lens patterns 115 of the engraved angle.

The light sources 131 may be two-dimensionally arranged at equal intervals behind the light guide plate 110.

The light source 131 may be configured using an LED. In this case, when the light source 131 is implemented as a white light source using an LED, a method of simultaneously using three primary colors of red, green, and blue LEDs, A method of forming a white light source by applying a fluorescent material emitting yellow light to the LED of FIG.

The light source 131 may be an LED formed by combining one or more of white, red, orange, yellow, green, blue, indigo, or purple.

The light from the light source 131 is transmitted and refracted through the conical lens pattern 115 of the intaglio angle to the concave reflection pattern 113 of the intaglio angle and diffused to the inside of the light guide plate 110 The light is emitted to the front surface of the light guide plate 110 or partially reflected on the upper surface thereof to be reflected downward. At this time, in the conical lens pattern 115 of the concave shape, the light transmitted and refracted by the concave reflection pattern 113 of the concave angle is partially reflected by the concave reflection pattern 113 of the concave angle into the light guide plate 110, And the remaining part is transmitted and straightened in the upward direction. At this time, the light transmitted through the concave reflection pattern 113 of the concave shape upward is reflected into the light guide plate 110 by the reflection sheet 140.

The light totally reflected by the concave reflection pattern 113 is reflected and diffused into the light guide plate 110 by the light diffusion pattern 114 formed on the lower surface of the light guide plate 110, The light that is reflected or refracted by the pattern 114 and passes downward is reflected to the inside of the light guide plate 110 by the reflective layer 120 so that the light of the light source 131 incident into the light guide plate 110 Is converted into a surface light source by the total reflection and the diffuse reflection.

Therefore, in the direct-type surface light source device 100 according to the embodiment of the present invention, total reflection and diffused reflection are smoothly performed inside the light guide plate 110 due to the optical patterns formed on the upper and lower portions of the light guide plate 110, The luminance is not unnecessarily attenuated in the emission path of the light source. Accordingly, the direct light source device 100 has no partial difference in light and shade after being converted into the surface light source, and the light scattering is well performed inside the light guide plate 110, thereby increasing the effective area of the surface light source .

Therefore, the direct-type surface light source device 100 of the embodiment can greatly improve the light luminance and the light efficiency as the surface light source is improved. In addition, even when a small number of light sources 131 are used, light brightness and light efficiency can be greatly improved, and the thickness of the surface light source device can be reduced.

In the embodiment of the present invention, examples of the direct-type surface light source device 100 having a circular shape are shown in the figure, but various shapes and shapes may be used depending on the needs, such as an ellipse, a rhombus, a triangle, a rectangle, Shape.

Examples of optical pattern dimensions of the light guide plate 110

12 and 13 are sectional views for explaining the shape and size of the conical reflection pattern 113 and the intaglio lens pattern 115 formed on the light guide plate 110. FIG.

The shape and size of the optical pattern formed on the light guide plate 110 can be configured with the following design dimensions in the direct-type surface light source device 100 according to the embodiment of the present invention.

12 and 13, the thickness a of the light guide plate 110 may range from 4.5 to 5.5 mm (for example, 5 mm). At this time, the thickness b of the reflective layer 120 may be 0.15-0.25 mm (for example, 0.20 mm).

The conical reflection pattern 113 may have a pattern width c of 9.00 to 10.00 mm (for example, 9.50 mm) on the upper surface of the light guide plate 110, (D) of the pattern of 1.50 to 2.00 mm (e.g., 1.70 mm), and the two sides between the apexes of the cones may be made of arcs (m, n) each having a radius of 19 to 20 mm have.

The conical lens pattern 150 may have a width e of 7.00 to 8.00 mm (for example, 7.27 mm) on the lower surface of the light guide plate 110, And a depth f of the pattern of 7.00 to 7.50 mm (for example, 7.27 mm) inwardly. The two sides between the apexes of the cone may have a depth between the vertexes of 85 to 95 degrees (for example, 90 degrees) (I, k) having a radius (h) and a radius of 9 to 10 mm.

Here, the gap g between the conical reflection pattern 113 and the conical lens pattern 115 may have a size of 0.40 to 0.80 mm (for example, 0.60 mm).

The dimensions of the optical pattern of the light guide plate 110 are described as an example and may be designed differently depending on the size of the direct-type surface light source device 100, the thickness and length (size) of the light guide plate 110, . However, although the dimensions of the conical reflection pattern 113 and the conical lens pattern 115 may vary according to the size of the light guide plate 110, the shape and the shape of the conical reflection pattern 113 are the same as those described above and shown in FIGS. 12 and 13 .

As described above, in the direct-type surface light source device according to the present invention, a conical reflection pattern of a negative angle and a conical lens pattern of a negative angle are formed on an upper surface and a lower surface of a light guide plate having a light diffusion pattern, a reflection layer is disposed on a lower surface of the light guide plate, The light source is arranged inside the conical lens pattern of a negative angle and the light of the light source incident on the inside of the light guide plate is converted into a surface light source by total reflection and diffuse reflection and then emitted, It is possible to solve the technical problem.

It will be apparent to those skilled in the art that various modifications and changes can be made in the present invention without departing from the spirit or scope of the present invention as defined by the appended claims. It will be appreciated that such modifications and variations are intended to fall within the scope of the following claims.

100: direct-type surface light source device 110: light guide plate
111: body 112: upper surface
113: conical reflection pattern of the engraved 114: light diffusion pattern
115: Conical-type lens pattern 120 of a negative angle:
121: body 122: hole
130: substrate 131: light source
140: reflective sheet

Claims (4)

A light guide plate formed of a light transmitting material and having a light diffusion pattern integrally formed on the entire lower surface thereof;
A conical reflection pattern formed on the upper surface of the light guide plate and formed inwardly;
A concave lens pattern formed on an inner surface of the lower surface of the light guide plate and facing the conical reflection pattern of the concave shape;
A reflective layer disposed on the lower surface of the light guide plate and reflecting light, and having a hole for exposing the conical lens pattern of the engraved angle;
A substrate disposed below the reflective layer and having a light source arranged at a predetermined interval on the upper side so as to be disposed inside the conical lens pattern of the negative oblique angle; And
A reflective sheet disposed on the conical reflection pattern of the light guide plate at a predetermined size;
Wherein the light source is a light source.
The method according to claim 1,
The light of the light source is transmitted and refracted through the conical lens pattern of the intaglio angle with the conical reflection pattern of the intaglio angle and is totally reflected into the light guide plate through the conical reflection pattern of the intaglio angle and the reflection sheet, The light is reflected and diffused to the inside of the light guide plate,
Direct type surface light source device.
The method according to claim 1,
The reflective layer is composed of a sticky or adhesive sheet,
Wherein the reflective sheet comprises a tacky or adhesive sheet,
Direct type surface light source device.
The method according to claim 1,
Wherein the concave reflection pattern of the concave shape has a conical shape and two sides between the apexes of the conical shape arc respectively,
Wherein the concave lens pattern of the concave shape has a conical shape and two sides between the apexes of the cone form a straight line and a circular arc having a predetermined length,
Wherein the conical reflection pattern of the engraved and the conical lens pattern of the engraved are in a regular or irregularly arranged,
Direct type surface light source device.

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