KR101943836B1 - The Direct-type surface light source device - Google Patents

Abstract

An embodiment of the present invention provides a direct type surface light source device. The direct type surface light source device comprises: a light guide plate formed of a translucent material and having a cylindrical lens pattern with intaglio formed inward from a lower surface thereof; a substrate on which a light source is disposed at a predetermined interval on an upper side to be disposed inside the cylindrical lens pattern of the intaglio; and a reflective sheet disposed at a predetermined size on the cylindrical lens pattern of the light guide plate. Therefore, when a groove with the intaglio is formed on a lower surface of the light guide plate, the direct type surface light source device may obtain uniform brightness without blackening and whitening even if a distance between a light guide surface and screen is reduced to 20 nm or less by forming the circular reflective sheet on an upper surface of the groove and converting light from the light source disposed at the groove into a surface light source by total reflection and diffused reflection to output the light.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct-type surface light source device,

The present invention relates to a direct-type surface light source device.

More particularly, the present invention relates to a direct-type surface light source device capable of reducing the thickness of a product while obtaining a uniform luminous intensity.

LED (Light Emitting Diode) light source is a next generation light source because of its long life and energy efficient and environmentally friendly characteristics. However, the LED light source has some problems to be solved such as heat generation, price, uneven brightness. Particularly, there is a disadvantage that the life and the efficiency are inferior unless a heat radiation design is performed because a lot of heat is generated.

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.

The direct type is a method of arranging the light source on the back side of the light guide plate and sending light to the front side, which is advantageous for adjusting the brightness and color. 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 case of the direct light type device, it is not easy to form a thin backlight because a distance from the light guide plate to the diffusion plate must be set at a certain distance in order 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. 10-1373600

SUMMARY OF THE INVENTION 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 greatly improving light luminance and light uniformity.

A light guide plate formed of a translucent material and having a cylindrical lens pattern of a concave shape formed inward from a lower surface thereof; A substrate on which a light source is disposed at a predetermined interval on an upper side so as to be disposed inside the cylindrical lens pattern of the negative oblique angle; And a reflective sheet disposed at a predetermined size on the cylindrical lens pattern of the light guide plate.

The lower surface of the lens pattern may have a downward convex surface.

When the thickness of the light guide plate is 4 to 5 mm, the lens pattern has a diameter of 6.5 to 7.5 mm, and the reflective sheet may have a circular shape having a diameter of 15 to 20 mm.

When the ratio of the depth of the lens pattern formed from the lower surface of the light guide plate to the distance from the lower surface of the lens pattern to the upper surface of the light guide plate is A: B, A has a range of 4.0 to 4.5, B has a range of 0.5 to 1.0 Lt; / RTI >

According to the present invention, when an engraved groove is formed on the lower surface of the light guide plate, a circular reflective sheet is formed on the upper surface of the groove to convert light from the light source disposed in the groove into a planar light source by total reflection and diffuse reflection, , Even if the distance between the light guide surface and the screen is reduced to 20 mm or less, a uniform brightness without blackening phenomenon or whitening can be obtained.

In addition, the light intensity and the light efficiency can be greatly improved while using a small number of light sources, and the power consumption can be reduced to 1/3 or less as compared with the conventional technology, so that the maintenance cost can be reduced.

In addition, the maximum efficiency can be obtained by specifying the optimum light guide plate thickness, the optimum groove size, the size of the reflective sheet and the shape of the groove through various experiments.

1 is a perspective view of a direct-type surface light source device according to an embodiment of the present invention.
2 is an exploded perspective view of a light guide plate and a substrate of the direct underlying type surface light source device of FIG.
3 is a cross-sectional view of the direct underlying type surface light source device of FIG.
Figure 4 shows the shape of the substrate for the second test.
Figures 5A-5C show the shape of the substrate for the third test.
6 is a cross-sectional view of a light guide plate of a comparative example of the fourth test.
FIGS. 7A and 7B show the light quantity of the light guide plate according to the groove shape of 5 mm thickness.
8A and 8B show the light quantity of the light guide plate with a thickness of 4 mm according to the groove shape.
Fig. 9 is a graph showing a light amount according to a groove shape in a light guide plate having a thickness of 3 mm.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a direct-type surface light source device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a light guide plate and a substrate of the direct- Fig.

1 to 3, a direct-type surface light source device 100 according to the present invention includes a light guide plate 110 having a cylindrical lens pattern 115 having a concave surface formed on a lower surface thereof, a light guide plate 110 disposed below the light guide plate 110, A substrate 130 on which a light source 131 is disposed at a predetermined interval so as to be disposed inside a cylindrical lens pattern 115 having a negative obtuse surface, a reflective layer 120 disposed on the substrate 130 to reflect light, And a reflective sheet 140 disposed on the lens pattern 115 in a predetermined size corresponding to the cylindrical lens pattern 115 of the light guide plate 110.

The light guide plate 110 may be formed of a light-transmissive material, and the light diffusion pattern (not shown) 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 thickness of the light guide plate 110 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. 3 to 5 mm. More specifically, the thickness of the light guide plate 110 may be 4 mm.

Generally, 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 a 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 surface light source device 100 of the present invention controls the depth of the groove of the lens pattern 115, the shape of the groove and the size of the reflective sheet 140 while the thickness of the light guide plate 110 is 4 mm, It is possible to secure the brightness.

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.

In order to achieve this, the light guide plate 110 of the present invention has a light diffusion pattern integrally formed on the entire lower surface thereof, a cylindrical lens pattern 115 having a concave shape on the lower side, and a cylindrical lens pattern 115 of the light guide plate 110, The reflective sheet 140 is disposed on the upper surface of the light guide plate 110 at a position corresponding to the position where the light guide plate 110 is formed so that the light of the light source incident on the light guide plate is converted into a surface light source by total reflection and diffuse reflection, Can be implemented.

The light diffusion pattern may be formed integrally with the light guide plate 110 on the entire lower surface of the light guide plate 110.

The light diffusion pattern may be formed by regularly or irregularly arranging one or more shapes selected from among cones, triangles, and beards at predetermined intervals. The light diffusion pattern may be 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 can be adjusted in width, interval, etc. of each pattern by the pattern, and includes patterns or styles that are regularly or irregularly repeated.

The light diffusion pattern having such a shape realizes a planar light source by scattering and diffusing the light incident on the irregular surface of the pattern to the total interior of the light guide plate 110 by diffusing the light totally reflected, do.

The recessed cylindrical lens pattern 115 may be formed in the shape of an indentation inward from the lower surface of the light guide plate 110. At this time, the cylindrical lens pattern 115 of the intaglio angle has a cylindrical shape, and the upper surface of the cylindrical groove has a convex curved surface. The diameter of the groove may be about 7 mm, and the curved surface of the engraved cylindrical lens pattern 115 may have a radius of curvature of 27 to 30 mm, preferably 27.72 mm.

The intaglio cylindrical 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. The light diffusion pattern formed on the light guide plate 110 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 fine pattern such as the light diffusion pattern and the engraved lens pattern 115 can be formed through the injection mold. At this time, the light diffusion pattern formed on the light guide plate 110 and the intaglio lens pattern 115 may be formed by optical design.

Light that is emitted (transmitted) to the upper portion of the light guide plate 110 is reflected into the light guide plate 110 by the reflection sheet 140 disposed on the cylindrical lens pattern 115.

Here, the reflective sheet 140 has a predetermined size to sufficiently cover the upper portion of the cylindrical lens pattern 115, and may have a predetermined shape such as a circular shape or a square shape, but may be circular. The reflective sheet 140 may be made of a sticky or adhesive sheet. The diameter W1 of the reflective sheet 140 may satisfy 15 mm to 20 mm. 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.

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A reflective layer 120, which reflects light, may be disposed on the upper surface of the substrate 130. 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 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 opposing the cylindrical lens pattern 115 of the intaglio angle so that the intaglio cylindrical lens pattern 115 is exposed 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 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 a flat or optical pattern, and may be attached to the lower surface of the light guide plate 110 in a close contact state.

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.

A substrate 130 including a light source 131 is 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 cylindrical lens pattern 115 of the intaglio angle. At this time, the number of the light sources 131 is the same as the number of the cylindrical lens patterns 115 of the intaglio. The position where the light source 131 is disposed may be opposite to the position where the engraved cylindrical lens pattern 115 is formed. Accordingly, the light source 131 may be regularly or irregularly arranged according to the arrangement of the cylindrical 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 emitted from the light source 131 is transmitted and refracted through the intaglio cylindrical lens pattern 115 and the remaining part is diffused into the light guide plate 110 and emitted to the front surface of the light guide plate 110, Some are reflected and down. At this time, light transmitted through and refracted from the intaglio cylindrical lens pattern 115 is totally reflected to the inside of the light guide plate 110, and the remaining part of the light is transmitted and straightened in the upward direction.

As described above, the light of the light source 131 incident into the light guide plate 110 is converted into a surface light source by total reflection and diffuse reflection.

Therefore, in the direct-type surface light source device 100 according to the embodiment of the present invention, total reflection and diffuse reflection are smoothly performed inside the light guide plate 110 due to the optical pattern formed in the lower portion of the light guide plate 110, The luminance in the path is not unnecessarily attenuated. 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.

In this surface light source device 100, brightness and uniformity are different depending on the depth of the lens pattern 115, the thickness of the light guide plate 110, the size of the reflective sheet 140, and the shape of the lens pattern 115.

Hereinafter, a method of extracting an optimal numerical value of the surface light source device through various tests will be described with reference to FIGS.

FIG. 4 shows the shape of the substrate for the second test, FIGS. 5A to 5C show the shape of the substrate for the third test, FIG. 6 is a sectional view of the light guide plate of the comparative example of the fourth test, FIGS. 8A and 8B show the light quantity of the light guide plate according to the groove shape of the light guide plate having the thickness of 4 mm, and FIG. 9 shows the light guide plate with the thickness of 3 mm, And the light amount according to the groove shape in the test.

First test

The depth h1 of the groove of the lens pattern 115 and the diameter W1 of the reflective sheet 140 were varied in the light guide plate 110 having a thickness of 5 mm and the intensity of light was detected and shown in Table 1.

Diameter of reflective sheet (mm) Strength of light No groove 10 600 ㏓ 13 630 ㏓ 15 630 ㏓ 20 650 pounds Depth of groove
2 mm 10 590 pounds 13 600 ㏓ 15 590 pounds 20 620 ㏓ Depth of groove
3 mm 10 590 pounds 13 610㏓ 15 600 ㏓ 20 650 pounds Depth of groove
4 mm 10 670 pounds 13 680 ㏓ 15 680 ㏓ 20 720 pounds

As shown in Table 1, the reflective sheet 140 was tested to have diameters of 10, 13, 15, and 20 mm. When the groove depth h1 was 2 mm, The light intensity is measured at the points spaced at equal intervals from the respective grooves (at the positions spaced at the same intervals from the positions of the light emitting elements when there is no groove) with respect to the case where the groove depth h1 is 4 mm Respectively.

As a result of the measurement, it can be seen that a planar light source device having the highest intensity of light when the depth h1 of the groove is 4 mm with respect to the light guide plate having a thickness of 5 mm can be provided.

Second test

4, four lens patterns 115 having a groove of 4 mm as shown in the first test are formed on the light guide plate 110 having a thickness of 5 mm at intervals of 75 mm and then the diameter of the reflective sheet 140 (A region indicated by x) and a region 25 mm apart from the center by a distance of 25 mm in the direction perpendicular to the plane of the high-refractive-index plate 110, while changing the width W1 of the light beam to 10, 13, 15, Respectively.

center Above the center Comparative Example 1 1200 ㏓ 1040㏓ 4 mm
lens
pattern Diameter of reflective sheet
10mm 1170 pounds 1030㏓ 13mm 1200 ㏓ 1050 pounds 15mm 1190㏓ 1060 pounds 20mm 1220 ㏓ 1050 pounds

Referring to Table 2, after a lens pattern having a maximum light intensity of 4 mm is formed on the light guide plate 110 having a thickness of 5 mm, a region where the lens pattern 115 is not formed on the lens pattern 115, For example, the intensity of light in the central region and the intensity of light in a region above a predetermined distance from the central region are measured by varying the diameter of the reflection sheet 140.

As shown in Table 2, it can be seen that the light intensity at the center surface is the largest at 15 mm, and the light intensity at the center surface is the largest at 20 mm for the reflective sheet 140.

In Comparative Example 1, a light source was disposed under the light guide plate 110 without forming the lens pattern 115. The light guide plate of Comparative Example 1, the reflection sheet 140 of 20 mm in diameter, and the lens pattern 115 were formed. When comparing the embodiments, it is observed that the intensity of light is larger in the embodiment of the present invention.

Third test

LED light sources 131 are arranged in nine regions at intervals of 75 mm on the light guide plate 110 of 5 mm thickness as shown in Figs. 5A to 5C, Fig. 5A shows Comparative Example 2 in which the lens pattern 115 is not formed, 5B shows a lens pattern 115 having a depth of 4 mm and a reflective sheet 140 having a diameter of 15 mm formed on each lens pattern 115. Figure 5C shows a lens pattern 115 having a depth of 4 mm And a reflective sheet 140 having a diameter of 20 mm is formed on each of the lens patterns 115.

5A to 5C show the area where the LED light source 131 is disposed, and the x area is the area where the light intensity is measured.

Light intensity (average value) Remarks Comparative Example 2 1314.375㏓ 15mm reflective sheet 1452.5㏓ About 10% increase 20mm reflective sheet 1508.75㏓ About 14% increase

 Table 3 shows the averages of the intensity of each light in the x region.

As shown in Table 3, in the case of the embodiment in which the reflection sheet 140 of 20 mm is formed, the intensity of light of Comparative Example 2 is increased by about 14%.

The fourth test

When a lens pattern 115 having a groove with a depth of 4 mm is formed on a light guide plate 110 having a thickness of 5 mm and then a light diffusion sheet spaced apart from the light guide plate by a predetermined distance is formed, .

Distance to light diffusion sheet Comparative Example 3
(Average value) Reflective sheet diameter 15mm
(Average value) Reflective sheet diameter 20mm (average value) Remarks 10 mm 1292 ㏓ 1438㏓ 1364㏓ Visual Circle Observation 15 mm 1230 ㏓ 1378㏓ 1336㏓ Visual Circle Observation 20 mm 1180 ㏓ 1368㏓ 1306㏓ invisible 25 mm 1136㏓ 1310㏓ 1246㏓ invisible 30 mm 1116㏓ 1210㏓ 1170 pounds invisible

Table 4 shows that when the light diffusion sheets of 10, 15, 20, 25 and 30 mm in thickness are additionally provided on the light guide plate 110, The diameter of the reflective sheet 140 is 20 mm and the diameter of the reflective sheet 140 is 20 mm.

As shown in Table 4, when the light-diffusing sheet is 20 mm or more, the circle in which the light source 131 is visually observed is not observed, and the intensity of light is highest when the light-diffusing sheet is 20 mm thick. In the case of the light diffusing sheet having a thickness of 20 mm, the light intensity of about 15% with respect to the comparative example 3 is increased when the reflective sheet is 15 mm, whereas when the reflective sheet 140 is 20 mm, It has about 10% increased light intensity.

Therefore, in the case of having the light diffusion sheet, the light efficiency is increased when the reflective sheet 140 has a distance of 20 mm from the light guide plate 110 and a diameter of 15 mm on the lens pattern 115.

Fifth test

In the fifth test, the thickness of the light guide plate 110 is changed to 5 mm, 4 mm, and 3 mm, and the light intensity is measured by dividing the shape of the groove of the lens pattern 115 into a case of an angle and a case of a curved surface.

At this time, the reflective sheet 140 is formed to have a diameter of 15 mm, and the depth h1 of the groove of the lens pattern 115 and the distance from the end of the groove to the light guide plate 110, regardless of the thickness of the light guide plate 110, (h2) ratio satisfies 4.2: 0.8.

That is, as shown in FIG. 6, intensity of light was measured in the case where the upper surface 116 of the groove has an angle to the side surface and the surface of the groove has a curved surface in the cross section of the lens pattern 115.

Fig. 7A shows the case where the angle of Fig. 6 of a 5 mm-thick light guide plate is present, and Fig. 7B shows the case where the light guide plate has a curve of Fig.

 Fig. 8A shows the case of the angle of Fig. 6 of a 4 mm thick light guide plate, and Fig. 8B shows the case of Fig. 3 of the 4 mm thick light guide plate.

Fig. 9 shows a case in which the light guide plate having a thickness of 3 mm has the curve of Fig.

7A to 9 are regions where the light sources are arranged, and x regions are regions where light intensity is measured.

The numerical value at the bottom of x indicates the intensity of light in each area.

The depth of the groove of the lens pattern 115 satisfies 4.2 mm in the case of the light guide plate 110 of 5 mm in thickness and the depth of the groove of the lens pattern 115 satisfies 3.36 mm in the case of the light guide plate 110 of 4 mm in thickness And in the case of the light guide plate 110 having a thickness of 3 mm, the depth of the groove of the lens pattern 115 satisfies 2.52 mm.

Light guide plate thickness Angular
Lens pattern Curved lens pattern Growth rate
(Curved lens pattern) 5mm 1587.78 ㏓ 1778.8 ㏓ About 14% 4mm 1594.4㏓ 1907.78 ㏓ About 22% 3mm X 1712.2㏓ Approximately 9.8%

As shown in Table 5, the largest light intensity is observed when the light guide plate 110 having a thickness of 4 mm is used. Particularly, the curved lens pattern 115 has a light intensity of about 22% .

Accordingly, when the upper surface of the groove is formed to have a curved surface on the light guide plate 110 having a thickness of 4 mm while the ratio of the groove to the depth h1 is 4.2: 0.8, the intensity of light and the diffusion of light can be satisfied . In addition, since the light diffusion sheet disposed with a distance of 20 mm can achieve high light intensity without blackening or whitening, the distance between the screen and the light guide plate can be reduced, and the thickness of the module can be drastically reduced. The range is wider.

When the ratio of the depth of the lens pattern formed from the lower surface of the light guide plate to the upper surface of the light guide plate is A: B, A is 4.0 to 4.5 , And B is preferably in the range of 0.5 to 1.0.

As a result, the loss of light is reduced and the light intensity is increased, so that the power consumption is reduced to at least 300% and the maintenance cost can be reduced.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is by way of example only.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (4)

A light guide plate formed of a translucent material and having a cylindrical lens pattern of a concave shape formed inward from a lower surface thereof;
A substrate on which a light source is disposed at a predetermined interval on the upper side so as to be disposed inside the cylindrical lens pattern of the negative oblique angle;
A reflective layer disposed on an upper surface of the substrate and reflecting light; And
And a reflective sheet disposed on the upper surface of the light guide plate at a position corresponding to a position where the cylindrical lens pattern is formed,
The lower surface of the lens pattern has a curved surface which is convex downward,
When the ratio of the depth of the lens pattern formed from the lower surface of the light guide plate and the distance from the lower surface of the lens pattern to the upper surface of the light guide plate is A: B,
A has a range of 4.0 to 4.5,
And B is in the range of 0.5 to 1.0. delete The method according to claim 1,
Wherein the lens pattern has a diameter of 6.5 to 7.5 mm when the thickness of the light guide plate is 4 to 5 mm, and the reflective sheet has a circular shape having a diameter of 15 to 20 mm.















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