KR101304438B1 - Diffuser plate for saving LED lighting - Google Patents

Abstract

The present invention relates to an LED lighting-saving diffusion plate, and more particularly, to a diffusion plate for a display device using a plurality of direct-type LED lights, the substrate layer having a light incidence surface into which light is incident and the substrate on which light is emitted. A diffusion plate including a pattern layer on one surface of the layer, wherein the pattern layer is formed in a plurality of square pyramidal shapes, the plurality of square pyramids are in close contact and are arranged without a distance, the luminance value distribution in the diffusion plate 2A = B, It provides an LED light-saving diffusion plate, characterized in that 2A '= B.

Description

[0001] Diffuser plate for saving LED lighting [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED light-saving diffusion plate, and more particularly, to a diffusion plate capable of saving LED illumination in a liquid crystal display including LED light.

Generally, as backlights for liquid crystal displays, there are two schemes called edge-light type backlights and direct-under type backlights, but direct-type backlights that can realize low cost and high brightness are widely used for large-sized display devices. As a direct-type backlight, a linear light source such as a conventional cold cathode tube is designed as a base, and a method of emitting light by using a diffusion plate or an optical film is employed.

However, in recent years, from the viewpoints of environmental problems, lifetime of a light source, luminous efficiency, and improvement of image quality, a light source shift to an LED is strongly demanded instead of a cold cathode tube. Since the cold cathode tube is a light source, LED is a point light source, so a diffusion plate or an optical film is required to convert a point light source into a planar light source. On the other hand, in recent liquid crystal displays, there is a strong demand for energy saving (reduction in the number of light sources) and thinning. For backlight, there is a demand for a technique of reducing the light source and diffusing light at a short distance from the light source to the diffusion plate.

Conventionally, as a light diffusing technique for a point light source, a light distribution characteristic on a light diffusing plate in a direction perpendicular to the longitudinal direction of a back light emitting surface at a position on a corresponding diffuser plate just above the midpoint of the light source, There has been proposed a direct type backlight device having an optical sheet having a light condensing property on a plate.

Also disclosed is a method for improving the luminance uniformity of an LED light source by superimposing two diffusion plates with a lens having a high total light transmittance and diffusion plates having a low total light transmittance.

However, since a method using an optimized LED illumination is not disclosed in the related art, many LED lights are used to improve the luminance, which raises a production cost.

Therefore, it has been desired to develop a diffuser plate with improved brightness and diffusibility while saving LED illumination by using optimized LED illumination.

In order to solve the above problems, an object of the present invention is to optimize the LED illumination in using a diffuser plate in a liquid crystal display device so as to use the diffused plate at a minimum.

Another object of the present invention is to provide a diffusion plate that can be used to save the LED lighting, the brightness and uniformity in using the diffusion plate in the liquid crystal display device.

In order to achieve the above object, the present invention is a diffuser plate for a display device in which a plurality of direct type LED lighting is arranged horizontally and vertically, the base layer having a light incident surface to which light is incident and the base layer from which light is emitted A diffusion plate including a pattern layer on one surface of the pattern layer is formed in a plurality of square pyramid shape, the plurality of square pyramid shape is arranged in close contact with no separation distance, the luminance value distribution in the diffusion plate 2A = B, 2A Provided is an LED light-saving diffusion plate, characterized in that '= B.

In another aspect, the present invention provides a LED light-saving diffusion plate, characterized in that the side of the square pyramid shape is a square of 30 ~ 300㎛, the side surface is an equilateral triangle.

In another aspect, the present invention provides a LED light-saving diffusion plate characterized in that the corner portion of the square pyramid shape is rounded to have a radius of curvature.

In another aspect, the present invention provides an LED light-saving diffuser plate, characterized in that the square pyramid shape is the same size and the same shape.

Further, the present invention provides an LED light-saving diffusion plate characterized in that a plurality of the LED lights have the same luminous intensity at the time of LED lighting arrangement.

In another aspect, the present invention provides an LED lighting-saving diffuser plate characterized in that it further comprises light diffusing particles in the base layer.

In another aspect, the present invention provides an LED illumination-saving diffuser plate, characterized in that the illuminance is further formed on at least one of the incident surface of the substrate layer or the light exit surface of the pattern layer.

The LED light-saving diffusion plate according to the present invention has an effect of improving luminance and uniformity even though an optimal LED illumination is used.

Further, the LED light-saving diffusion plate according to the present invention has advantages of being able to exhibit luminance and uniformity even with a much smaller number than existing LED lights, thereby reducing cost.

1 is a perspective view of a diffusion plate according to an embodiment of the present invention.
Figure 2 shows a longitudinal cross-sectional view of the diffusion plate according to another embodiment of the present invention.
3 is a diagram illustrating a luminance value distribution generated when light emitted from one LED lighting lamp passes through a diffusion plate.
Figure 4 shows the luminance value distribution when the light emitted from the light source of the plurality of LED lighting lamps passed through the diffusion plate.
Figure 5 is a schematic diagram of the arrangement of the LED lighting lamp when using the diffusion plate according to an embodiment of the present invention (A) and the effect (2) of the LED lighting lamp when 2A = B and 2A '= B state (b) .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

The terms " about ", " substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation to or in the numerical value of the manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The present invention provides a diffuser plate for a display device in which a plurality of direct-type LED lights are arranged horizontally and vertically, wherein a pattern layer is provided on one surface of the substrate layer having a light incident surface to which light is incident and the substrate layer from which light is emitted. The diffusion plate including, the pattern layer is formed in a plurality of square pyramid shape, the plurality of square pyramid shape is in close contact with each other so as to be arranged without a distance, it is characterized in that the LED lights are appropriately disposed.

The pattern layer is positioned in the direction in which light is emitted and forms an embossed square pyramid shape. The brightness is improved due to the embossed square pyramid shape, which saves the number of LED lights located below the diffuser plate and makes it impossible to visually identify the shape of the lamp.

1 is a perspective view of a diffusion plate according to an embodiment of the present invention.

In FIG. 1, the pattern layer has a plurality of square pyramid shapes in a protruding embossed shape, and the square pyramid shapes are arranged in close contact without a distance. Preferably, the base surface of the square pyramid forms a square and the side surface constitutes an equilateral triangle structure.

The diffusion plate of the present invention, which has the shape of a square pyramid as described above, has excellent characteristics such as high visibility as well as excellent diffusion effect.

The quadrangular pyramid shape serves to diffuse and condense the incoming light, and the light focused or diffused by the quadrangular pyramid moves in the direction of the liquid crystal display panel.

In addition, the quadrangular pyramid shape is arranged in close contact with no spacing distance, but when the direct type LED lighting lamps are arranged in a minimum number, the pyramid shape is caused to show a bright phenomenon when the spacing is arranged at the quadrangular pyramid shape. Therefore, the present invention is characterized in that it is arranged in close contact with the spacing without the square pyramid shape.

Further, optionally, the vertex angle may be rounded in a curved shape in the square pyramid shape, and FIG. 2 illustrates a longitudinal cross-sectional view of a diffusion plate according to another exemplary embodiment of the present invention. A vertex is the point where the triangles on the sides of the polygonal pyramid gather to form an angle. Therefore, when the vertex portion of the triangular shape of the unit structure in the longitudinal cross section (Fig. 2) is rounded, it has a predetermined radius of curvature (R).

The square pyramid shape is preferably 30 to 300 µm in length, and a side surface is an equilateral triangle. The length of one side of the equilateral triangle of the side surface can be seen to have a common length with the length of one side of the base of the square pyramid shape, the length of the equilateral triangle is also 30 ~ 300㎛.

In addition, although the quadrangular pyramid shape has a plurality in the pattern layer of the diffusion plate, the quadrangular pyramid shape preferably forms the same shape of the same size.

The base layer is located in a direction in which light is incident from the LED light source, and the base layer is preferably disposed flat with the LED light source surface.

The substrate layer has an approximately flat light incident surface on which light is incident from a light source or a lamp. The thickness of the base layer is not particularly limited, but is preferably 0.1 mm to 5.0 mm. If the thickness of the base layer is less than 0.1mm, the diffusion plate is difficult to maintain a constant rigidity, there is a disadvantage that does not support the optical subsidiary materials stacked on the diffusion plate. Therefore, the base layer has a certain thickness, so that the necessary rigidity as the diffusion plate can be obtained and the optical auxiliary material can be protected from heat generated from the light source. If the thickness of the base layer exceeds 5mm, there is a problem in that the manufacturing cost of the light diffusion plate increases, and as the thickness increases, the weight of the direct backlight unit may increase.

On the other hand, when the diffusion plate of the present invention is used, high brightness can be obtained by using an optimal LED illumination lamp.

In general, when a large amount of lamps are used, the luminance may increase, but the amount of power increases along with the cost increase, thereby increasing the power consumption of the liquid crystal display device. On the other hand, if it is used in a small amount, the desired luminance value can not be obtained and the quality is deteriorated.

In the case of using the diffusion plate according to the present invention, it is possible to obtain the desired brightness by using the optimal LED lighting lamp when installing the LED lighting.

3 is a diagram illustrating a luminance value distribution generated when light emitted from one LED lighting lamp passes through a diffusion plate.

Referring to FIG. 3, when light is emitted from the LED light, which is a point light source, when the light passes through the diffusion plate, the luminance value is not distributed in all areas of the diffusion plate, but the luminance appears only for a certain area.

At each point of the diffuser plate, the point at which the luminance value is maximum, the point at 1/2 of the maximum point and the point at zero are displayed. The values of these points can be represented as shown in FIG. 3. In other words, as shown in FIG.

The luminance value at the point a is the luminance value at a point at a vertical distance from the lamp, and has a maximum value of the total luminance value. Further, the luminance value decreases as the distance a from the point a is increased. For example, when the luminance values are compared between the points b and c, the luminance value is smaller because the distance from the point a is farther from the point c than the point b. As such, when all of the points of the relative luminance values at each point are connected, they are distributed in a three-dimensional shape as shown in FIG.

To express this again in two dimensions, that is, the distribution observed in part (a) and the distribution observed in part (b) may be expressed as shown in (b) of FIG. 3. The distribution of the luminance value observed in the portion (a) and the distribution of the luminance value observed in the portion (b) are represented by the curvature lines as in (1) and (2).

If the maximum values of the curvature line and the curvature line are B and B, respectively, the maximum value is the same and B = B '. This can be easily determined from (a) of FIG.

FIG. 4 is a curve showing a luminance value distribution diagram when light emitted from a light source of the LED illumination lamp passes through a diffuser plate when several direct type LED lighting lamps are arranged based on the concept of the luminance value distribution diagram of FIG. 3. It is shown as.

A, A ', B and B' represent the luminance value distribution curves when passing through a diffusion plate at a specific point, and B and B 'represent the maximum value from the vertical distance of the LED illumination lamp, A is a luminance value at a point having the same luminance value of the light source a and the light source b. That is, at a point where the luminance values of the light source a and the light source b are equal to each other, the luminance value represents the luminance value A obtained by combining the luminance value A from the light source a and the luminance value A from the light source b.

Similarly, A 'refers to a luminance value at a point where the luminance value of the light source b and the luminance value of the light source d are the same.

When the light emitted through the diffuser is in the state of 2A = B and 2A '= B, the arrangement of the LED illumination lamps can be arranged in an appropriate and optimal state. When 2A = B, the point representing the distribution of the luminance value of A has the same effect as that of the LED light because the luminance values from the light source a and the light source b are added.

That is, when the luminous intensities of all the light sources are the same, when 2A = B and 2A '= B, the distance between the light source a and the light source b, the distance between the light source a and the light source c, b and the light source d, and the light emitted from the light source a to the intermediate point between the light sources a to d, overlap each other, so that a new light source exists. That is, it can be seen that there is a dummy lamp.

Therefore, the light source a and the light source b, the intermediate point between the light source a and the light source c, the intermediate point between the light source b and the light source c, the intermediate point between the light source b and the light source d, There is no need to install additional, so LED lighting lamp can be saved.

On the other hand, if the arrangement of the LED lighting lamps is made such that 2A> B and 2A '> B, the intensity of the light increases at the midpoint of each light source (light source a to light source d) do.

In addition, if the arrangement of the LED lighting lamps is made such that 2A > B and 2A ' > B, the light intensity is weak at the midpoint of each light source (light source a ~ light source d) .

Accordingly, when the diffusion plate of the present invention is used, the arrangement of the LED lighting lamps can be optimized so that 2A = B and 2A '= B, and the LED lighting can be saved.

5 is a schematic view of the arrangement of the LED lighting lamp when using the diffusion plate according to an embodiment of the present invention and shows the effect of the LED lighting lamp when 2A = B and 2A '= B state.

In the case of arranging 5 × 4 LED lighting lamps horizontally and vertically as shown in (a) of FIG. 5, if the 2A = B and 2A '= B states are arranged, the same effect as that of FIG. 4B is obtained. It has the same effect as arranging × 7, resulting in an additional 43 dummy lamps.

Therefore, the use of the diffusion plate according to the present invention is very effective in reducing the production cost.

On the other hand, the substrate layer may further include light diffusing particles for the diffusion effect, because the light diffusing particles should be compatible with the binder (resin) containing the particles, because the organic particles similar to the refractive index of the material and spheres with low refractive index The silicon particles in the form were examined and used, and inorganic particles having a refractive index of 1.50-1.80 can be used. Particularly, the particles to be used are spherical particles having a refractive index difference of 0.1 to 0.2 with respect to the material, which is advantageous in solving the problems such as visibility of bright lines by enhancing the shielding property and maximizing the diffusion effect with a relatively small amount of particles It is very advantageous because.

The refractive index of the light diffusing particles used improves the light diffusion effect as the difference between the material and the refractive index increases. However, if the refractive index difference is too large, the refractive index difference is disadvantageous in terms of increasing the luminance. It is preferable to use particles having a large refractive index difference in combination.

Non-limiting examples of the light-diffusing particles that can be used in the present invention include methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, n-butyl methyl methacrylate, acrylic acid, Hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, methacryl acrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate and 2 -Ethylhexyl acrylate, beads and silicone spherical particles made of polyethylene, polystyrene, polypropylene, acrylic and olefin-based copolymers, and the like can be used. Preferably, the material is spherical particles having a refractive index difference of about 0.1 to 0.2 and a particle size of 1 to 10 占 퐉. The spherical organic particles having the refractive index difference can be easily dispersed in the resin because they have a density similar to that of the material used in the present invention (about 1.10 to 1.30 g / cm3).

The light diffusing particles used in the present invention may be different in kind and / or size. For example, it is possible to increase the light diffusion efficiency by mixing two or more kinds of particles having different refractive indexes than a single kind. In addition, it is possible to increase the light diffusion efficiency by using particles having different refractive indices and different sizes, and by applying hollow particles, brightness can be increased while maximizing the light diffusion efficiency after assembling the backlight unit.

When particles having a uniform particle size are used, a large amount of particles are required for achieving a predetermined light diffusion effect, which results in not only economic inefficiency but also lowered overall light transmittance. According to a specific example of the present invention, it is possible to increase the light diffusion effect while reducing the content of the particles by using particles of two sizes of light diffusion particles of 20 to 30 탆 and 1 to 15 탆.

The light diffusing particles may be used at 0.5 to 20% by weight, preferably 1 to 10% by weight based on the total weight of the base layer. When the light diffusing particles are 0.5 wt% or less, a predetermined light diffusing effect cannot be obtained, and when the light diffusing particles is more than 20 wt%, the light transmittance is lowered, and the dispersibility of the particles is reduced and uniform. Particle dispersion cannot be obtained.

According to the present invention, it is preferable that roughness (roughness) is further formed on at least one of the incident surface of the base layer or the light exit surface of the pattern layer. The illuminance serves to diffuse light. In addition, the illuminance cancels the light so as to cancel the image of the lamp to obtain a uniform image.

In general, if a scratch is generated in the diffusion plate, light may not be diffused normally, thereby degrading the quality of the liquid crystal display. In order to prevent this, a protective film is additionally required. Accordingly, a problem arises in that the cost of the protective film is further increased.

In order to solve this problem, when a predetermined illuminance is formed on the incident surface of the substrate layer of the diffuser plate or the light exit surface of the pattern layer, light may be diffused by the predetermined illuminance to prevent deterioration of quality even if a scratch occurs.

More specifically, roughness means the degree of minute unevenness occurring on the surface. The value indicating this is the centerline average roughness, which means the average height from the centerline to the cross-sectional curve, which can be represented by the Ra symbol.

The center line average roughness Ra value of the predetermined illuminance formed on the incident surface of the substrate layer of the diffusion plate or the light exit surface of the pattern layer is not particularly limited, but is preferably about 3 µm to 15 µm.

When the center line average roughness Ra is less than 3 μm, light cannot be diffused, and when a scratch occurs, it is easily identified with the naked eye, thereby degrading the quality of the liquid crystal display and reducing productivity. In addition, when the center line average roughness Ra exceeds 15 μm, light may not be evenly diffused, thereby degrading the quality of the liquid crystal display.

Therefore, in the diffuser plate according to the present invention, by providing roughness on the incident surface of the substrate layer of the diffuser plate, it is possible to provide a diffuser plate that is strong against scratches and has good light efficiency. Of course, by providing a diffuser plate formed with roughness, the diffusion plate according to the present invention does not need to attach a protective film has the effect of reducing the cost.

In addition, the illuminance may be formed on the emission surface of the pattern layer. If a predetermined illuminance is formed on the emission surface, light diffusion efficiency may be further increased. In addition, by forming a predetermined roughness, it is possible to prevent a decrease in visibility when a scratch occurs, thereby providing a diffusion plate having excellent quality. Of course, by providing a scratch-resistant diffuser plate can be reduced cost because the protective film is not required on the exit surface of the pattern layer.

The method of forming the roughness on the incident surface of the substrate layer or the exit surface of the pattern layer may form the roughness through a separate additional process. For example, the roughness may be formed by using a shape roll having a predetermined roughness, and the roll may be manufactured by engraving the surface of the roll by using an energy controlled laser, or by spraying fine metal onto the roll.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

Claims (7)

In a diffuser plate for a display device in which a plurality of direct-type LED lights are arranged horizontally and vertically,
A diffuser plate comprising a substrate layer having a light incident surface to which light is incident and a pattern layer on one surface of the substrate layer from which light is emitted. The pattern layer is embossed to form a plurality of square pyramid shapes, and the plurality of square pyramid shapes. Are closely spaced and spaced apart,
The square pyramid shape is the same size and the same shape,
Wherein the diffusing plate has a luminance value distribution of 2A = B and 2A '= B. The method of claim 1,
The square pyramid shape is a LED light-saving diffuser plate, characterized in that the base has a square side length of 30 ~ 300㎛, the side surface is an equilateral triangle. The method of claim 1,
The vertex angle of the square pyramid shape is a LED light-saving diffuser plate, characterized in that rounded to have a radius of curvature. delete The method of claim 1,
Wherein a plurality of said LED lights have the same luminous intensity at the time of LED lighting arrangement. The method of claim 1,
Wherein the base layer further comprises light diffusion particles. The method of claim 1,
LED illumination-saving diffusion plate, characterized in that the illuminance is further formed on at least one of the incident surface of the substrate layer or the light exit surface of the pattern layer.

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