TW202028792A - Method of fabricating light guide plate, light guide plate fabricated thereby, and illumination device having the same - Google Patents

Abstract

A method of fabricating a light guide plate (LGP), an LGP fabricated thereby, and an illumination device having the same. The method includes preparing an LGP and fabricating a light-scattering layer by printing a printing solution including light-scattering particles on an overall bottom surface of the LGP. The light-scattering layer may be fabricated by at least one of a first method of controlling the printing such that the density of the light-scattering particles gradually increases with increases in a distance from the light-emitting diode facing a side surface of the LGP and a second method of controlling the printing such that the thickness of the light-scattering layer gradually increases with increases in the distance from the light-emitting diode. A luminous point through can be prevented from being viewed by a front observer, a process can be simplified, and light distribution similar to Lambertian distribution can be obtained.

Description

Method for manufacturing light guide plate, light guide plate manufactured by the method, and lighting device having the light guide plate

This application claims the priority rights of U.S. Application No. 16/374,381 filed on April 3, 2019 in accordance with the Patent Law, and claims the Korean Patent Application No. 10-2018 filed on November 29, 2018 The priority rights of -0150797, which claim the priority rights of Korean patent application No. 10-2018-0116835 filed on October 1, 2018, the reference of this application as a whole combines each of the above Korean patent applications The disclosure of the person.

The present disclosure relates to a method of manufacturing a light guide plate (LGP), an LGP manufactured by this method, and a lighting device having the LGP, and more specifically, to a method of manufacturing an LGP, the LGP manufactured thereby, and The lighting device with this LGP can prevent the front observer from seeing the light-emitting point through which the captured light passes, simplify the manufacturing process, and obtain a light distribution similar to the Lambertian distribution.

Generally speaking, a light guide plate (LGP) is implemented using a highly transparent substrate (such as acrylic or polycarbonate). The LGP uses total internal reflection that occurs when light travels from a medium with a higher optical refractive index to a medium with a lower optical refractive index to distribute the light therein. When the light propagating in the LGP reaches (strike) the light extraction point (or position), the light will be refracted and leave the LGP. In this regard, the LGP must have a plurality of light extraction points, at which light is extracted outward. These light extraction points are usually manufactured by the following methods: the method of machining V-shaped grooves in the LGP, the method of manufacturing the lens using inkjet, and the patterned dots by screen printing as shown in Figure 10 The method of printing on the surface of LGP 3. However, in the case of printing the patterned dots 5 on the surface of the LGP 3, due to the significant distance between the dots 5, a diffuser sheet must be additionally provided.

As shown in FIG. 11, in response to the development of inkjet technology, it has recently been possible to print smaller dots 5. When the tiny dots 5 are randomly arranged to function like a diffuser sheet, the diffuser sheet may be omitted. However, when this structure is used in an actual lighting device, even if the size is reduced, the dot 5 manufactured by inkjet printing can be visually recognized. Specifically, stains or the like may occur due to process changes. For use in actual products, this structure may be somewhat incomplete.

In addition, because the number of dots 5 to be printed increases as the size of the dots 5 decreases, its mass production may require an extended amount of time, which is also problematic. Related technical literature

Patent Document 1: Korean Patent No. 10-0656896 (December 6, 2006)

Various aspects of the present disclosure provide a method of manufacturing a light guide plate (LGP), an LGP manufactured by this method, and a lighting device having the LGP, in which the front observer can be prevented from seeing the captured light The passing light-emitting points can simplify the manufacturing process and obtain a light distribution similar to the Lambertian distribution.

According to one aspect, a method for manufacturing a light guide plate used in an edge-emitting lighting device, the method includes the following steps: preparing a light guide plate, the light guide plate including a first surface, a second surface, and a third surface , The first surface faces a front observer and irradiates light through the first surface, the second surface is opposite to the first surface, and the third surface is connected to a surrounding portion of the first surface and the second surface A peripheral portion to connect the first surface and the second surface, the third surface facing a light emitting diode; and by printing a printing solution containing light scattering particles on the entire area of the second surface To make the light scattering layer. The light scattering layer can be manufactured by at least one of the following methods of controlling the printing step: the first method of controlling the printing step is such that as the distance from the light-emitting diode on at least one surface facing the third surface increases, the light The density of the scattering particles is gradually increased, and the second method of controlling the printing step makes the thickness of the light scattering layer gradually increase as the distance from the light-emitting diode on at least one surface facing the third surface increases.

Here, the method may further include the following step: manufacturing a printing solution before manufacturing the light scattering layer.

The printing solution can be manufactured by adding light scattering particles to the printing solution so that the amount of light scattering particles to the amount of printing solution ranges from 0.1% to 5% by weight.

The printing solution can be manufactured by adding light scattering particles to the printing solution, the light scattering particles including at least one selected from the following: TiO ₂ , ZrO ₂ , BaTiO ₃ and SnO ₂ .

The first method can control the printing step so that the number of light scattering particles per unit area changes by at least 1.2 times depending on the position.

The first method can control the printing step so that the light scattering layer is formed to have a uniform thickness over the entire area of the second surface.

The second method can control the printing step so that the thickness of the light scattering layer is in the range of 1 μm to 5 μm depending on the position.

The method may further include the step of curing the light scattering layer after manufacturing the light scattering layer.

According to another aspect, a light guide plate may include: a light guide plate main body including a first surface, a second surface, and a third surface, the first surface facing a forward observer and passing through the second surface A surface is irradiated with light, the second surface is opposite to the first surface, and the third surface is connected to a surrounding portion of the first surface and a surrounding portion of the second surface to connect the first surface and the second surface , The third surface faces a light emitting diode; and a light scattering layer, the light scattering layer is made on an entire area of the second surface, the light scattering layer includes a matrix layer and dispersed in the matrix layer Multiple light scattering particles. As the distance from the light emitting diode of at least one surface facing the third surface increases, the thickness of the light scattering layer may gradually increase.

According to another aspect, a light guide plate may include: a light guide plate main body including a first surface, a second surface, and a third surface, the first surface facing a front observer and passing through the first surface A surface is irradiated with light, the second surface is opposite to the first surface, and the third surface is connected to a surrounding portion of the first surface and a surrounding portion of the second surface to connect the first surface and the second surface , The third surface faces a light emitting diode; and a light scattering layer, the light scattering layer is made on an entire area of the second surface, the light scattering layer includes a matrix layer and dispersed in the matrix layer Multiple light scattering particles. As the distance from the light emitting diode on at least one surface facing the third surface increases, the dispersion density of the plurality of light scattering particles may gradually increase.

Here, the light scattering layer can be manufactured with a uniform thickness over the entire area of the second surface.

The surface of the light scattering layer may be a flat surface.

The surface roughness of the light scattering layer may be 100 nm or less.

Depending on the location, the thickness of the light scattering layer is in the range of 1 μm to 5 μm.

The light scattering particles may be formed of a material having a refractive index higher than that of the matrix layer.

The light scattering particles may be formed of at least one selected from the following: TiO ₂ , ZrO ₂ , BaTiO ₃ and SnO ₂ .

The light guide plate may have a hazing value of 30% or less and a transmittance of 50% or more.

According to another aspect, a lighting device may include: the light guide plate as described above; at least one light-emitting diode, the at least one light-emitting diode is arranged to face at least one surface of the third surface, and the third surface It is defined as a side surface of the light guide plate; and a frame, which provides a space for arranging the light guide plate and the light emitting diode.

When the light-emitting diode is turned on, light can be irradiated through the first surface and the second surface. The first surface is defined as the front surface of the light guide plate, and the second surface is defined as the front surface of the light guide plate. The back surface. When the light emitting diode is off (off), the front observer facing the first surface can observe the second surface through the light guide plate.

The lighting device may further include a reflector disposed adjacent to the second surface, and the second surface is defined as a rear surface of the light guide plate.

As described above, according to the present disclosure, the light-scattering layer including light-scattering particles is manufactured on the entire area of the rear surface of the LGP with respect to the front observer in a single printing process. Therefore, this can prevent the phenomenon that the light-emitting point through which the captured light passes is visible to the front observer, that is, the spot that appears in the inkjet printing in the prior art is the front due to the pattern mismatch or the regular patterned shape. Issues visible to the observer.

In addition, according to the present disclosure, the light scattering layer can be manufactured in a single printing process, the diffuser sheet provided in front of the LGP can be omitted, and additional layers (such as the low surface energy layer required in the case of manufacturing lenses) can be omitted. It is unnecessary, thereby simplifying the manufacturing process of the LGP.

In addition, according to the present disclosure, as the distance from the LED disposed on the LGP side surface increases, the density of the light scattering particles relative to the printing solution is controlled to gradually increase, or as the distance from the LED disposed on the LGP side surface increases, The distance between the LEDs increases, and the thickness of the light scattering particles is controlled to gradually increase. Therefore, this can prevent the problem of excessive light leaving the area adjacent to the LED, and can obtain a light distribution similar to the Lambertian distribution.

In addition, according to the present disclosure, the lighting device can be provided as a transparent lighting device. That is, when the LED is turned on, light can be irradiated through both the front surface and the rear surface of the LGP, and when the LED is turned off, any object behind the lighting device is visible to the front observer.

The method and device of the present disclosure have other features and advantages. These features and advantages will be highlighted in combination with the accompanying drawings and the following embodiments or will be described in more detail in the accompanying drawings and the following embodiments. Together with the following embodiments, it is used to explain some principles of the present disclosure.

Hereinafter, the method of manufacturing the light guide plate (LGP), the LGP manufactured thereby, and the lighting device having the LGP will be described in detail with reference to the drawings.

In the following description, when it contains circumstances that may make the subject matter of the disclosure unclear, the detailed description of the conventional functions and components incorporated herein will be omitted.

As shown in FIGS. 1 and 2, the method of manufacturing the LGP according to the exemplary embodiment is to manufacture the LGP 100 used in the edge-emitting lighting device 10 (see FIGS. 3 and 4). The edge-emitting lighting device 10 is set on its edge Illuminated by the light-emitting diodes (LED).

In this regard, a method of manufacturing an LGP according to an exemplary embodiment includes an LGP preparation step S110 and a light scattering layer manufacturing step S130. The method of manufacturing an LGP according to an exemplary embodiment may further include a printing solution manufacturing step S120 before the light scattering layer manufacturing step S130.

First, in the LGP preparation step S110, the LGP 100 is prepared as a transparent plate. For example, a substrate formed of acrylic or glass may be used to realize the LGP 100. When a transparent substrate is used to implement the LGP 100, a transparent LED lighting device can be provided so that the image behind the device is visible. In this regard, the LGP 100 may have a haze value of 30% or lower and a transmittance of 50% or higher. According to an exemplary embodiment, the surface of the LGP 100 facing a front observer through which light is irradiated will be referred to as the "front surface", and the surface of the LGP 100 opposite to the front surface will be referred to as " The "rear surface", the surface of the LGP 100 connected to the periphery of the front surface and the periphery of the rear surface to connect the front surface and the rear surface will be referred to as the side surface of the LGP 100.

After that, in the printing solution manufacturing step S120, a printing solution including the light scattering particles 130 is manufactured. Here, according to an exemplary embodiment, the content of the light scattering particles 130 in the printing solution must be very small when compared with the dot pattern printing solution of the prior art. When the light scattering layer 140 is manufactured in the light scattering layer manufacturing step S130 (to be described later), the light scattering layer 140 provides a surface instead of forming a dot shape of the prior art, thereby increasing the overall area. Therefore, a large amount of light leaves the area adjacent to the LED 200. In order to overcome this problem, the content of the light scattering particles 130 is set to be very small when compared with the dot pattern printing solution of the prior art.

In this regard, in the printing solution manufacturing step S120, the light scattering particles 130 may be added to the printing solution so that the content of the light scattering particles 130 may be in the range of 0.1% to 5% by weight relative to the printing solution. , And preferably may be 2% or less.

Here, according to an exemplary embodiment, a material having a refractive index different from that of a printing solution material may be used to realize the light scattering particles 130, particularly a material having a refractive index higher than that of the printing solution material. For example, in the printing solution manufacturing step S120, the light scattering particles 130 added to the printing solution may be at least one selected from the following: TiO ₂ , ZrO ₂ , BaTiO ₃ and SnO ₂ . However, this is only an example, and the light scattering particles 130 are not limited to the aforementioned materials. Instead, various other materials having a refractive index higher than that of the material of the printing solution may be used to realize the light scattering particles 130. Here, when BaTiO _{3 is} selected as the light scattering particles 130, a mixed solution of polysiloxane and dipropylene glycol methyl ether (DPM) can be used as a printing solution. However, this is only an example, and the printing solution is not limited to the above-mentioned mixed solution.

For example, when TiO _{2 is} selected as the light scattering particle 130, hexamethylene diacrylate, exo-1,7,7-trimethylbicyclo[2.2.1]heptan-2-acrylate (exo-1 ,7,7-trimethylbicyclo[2.2.1]hept-2-yl acrylate), benzyl acrylate, 2-methoxyethyl acrylate, and 2,4,6-trimethylbenzyl A mixture of diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide can be used as a printing solution.

After that, in the light scattering layer manufacturing step S130, the printing solution is printed on the entire area of the rear surface of the LGP 100, thereby forming a continuous light scattering layer 140 in which the light scattering particles 130 are dispersed. As described above, when the printing solution including the light scattering particles 130 having a significantly low content is printed on the entire area of the rear surface of the LGP 100, the surface of the light scattering layer 140 forms a flat surface. That is, no light scattering particles 130 protrude from the surface of the light scattering layer 140. For example, under light emission conditions where scattering reflection occurs on the surface of the light scattering layer 140, a surface roughness (Ra) of 100 nm or less is measured from a 10 μm×10 μm area of the surface of the light scattering layer 140 using an atomic force microscope (AFM). As mentioned above, only the light-scattering particles 130 dispersed in the scattering layer 140 can prevent the phenomenon that the light-emitting point through which the captured light passes is visible to the front observer, that is, due to mismatched patterns or regular patterned shapes, The stains that appear in the inkjet printing in the prior art are visible to the front observer.

In addition, since the light scattering layer 140 is manufactured to form a single surface covering the entire area of the rear surface of the LGP 100, instead of being manufactured as dot-patterned spots in the prior art, the LGP in the prior art can be omitted. The manufacturing method does not require additional layers (such as the low surface energy layer required in the case of manufacturing lenses), thereby simplifying the manufacturing process of the LGP. In addition, in the light scattering layer manufacturing step S130 according to an exemplary embodiment, the light scattering layer 140 may be manufactured in a single printing process, thereby simplifying the manufacturing process.

In addition, the light scattering layer manufacturing step S130 according to an exemplary embodiment uses at least one of the following methods of controlling the printing process: the first method of controlling the printing process makes the LED 200 according to at least one surface facing the side surface of the LGP 100 The distance, the content of the light scattering particles 130 in the light scattering layer 140 is changed in a position-specific manner, and the second method of controlling the printing process is such that the distance between the LED 200 and at least one surface facing the LGP 100 side surface For the distance, the thickness of the light scattering layer 140 varies in a position-specific manner. This feature aims to adjust the difference in light extraction efficiency according to the distance from the LED 200 disposed on the side of the LGP 100. That is, because in order to achieve uniform light distribution across the entire area, it is necessary to reduce the light extraction efficiency in the area closer to the LED 200 while increasing the light extraction efficiency in the area farthest from the LED 200, so as described above Control the printing process.

Specifically, the first method used in the light scattering layer manufacturing step S130 can control the printing process so that as the distance from the LED 200 on at least one surface of the side surface facing the side surface of the LGP 100 increases, it is relative to the printing solution. The density of light scattering particles per unit area gradually increases. For example, in the light-scattering layer manufacturing step S130, the printing process can be controlled so that the number of light-scattering particles 130 per unit area changes at least 1.2 times according to the position. For example, the printing process can be controlled so that the number of light scattering particles 130 dispersed in a part of the light scattering layer 140 adjacent to the LED 200 is 50%, and dispersed in a part of the light scattering layer 140 farthest from the LED 200 The number of light scattering ions 130 is 80%. Here, in the first method, the printing process may be controlled so that the thickness of the light scattering layer 140 is uniform across the entire area across the rear surface of the LGP 100. For example, in the first method, two solutions including light scattering particles formed of BaTiO ₃ are prepared, namely a solution in which the weight ratio of light scattering particles is 0.5% and a solution in which the weight ratio of light scattering particles is 1.2%. After that, prepare an inkjet head that can use both solutions. Subsequently, an inkjet head is used to print the light scattering layer with a uniform thickness so that the number of light scattering particles per unit volume varies according to position. In this case, by continuously changing the injection ratio of the two solutions while keeping the entire printing density constant, the light scattering layer with uniform printing thickness and different number of light scattering particles per unit volume can be printed and manufactured.

In addition, the first method used in the light scattering layer manufacturing step S130 can control the printing process so that the thickness of the light scattering layer 140 gradually increases as the distance from the LED 200 facing at least one of the side surfaces of the LGP 100 increases. . For example, in the second method used in the light scattering layer manufacturing step S130, the printing process may be controlled so that the thickness of the light scattering layer 140 is in the range of 1 μm to 5 μm depending on the position. That is, in the light scattering layer manufacturing step S130, the printing process can be controlled so that the thickness of a part of the light scattering layer 140 adjacent to the LED 200 is 1 μm, and the thickness of the part of the light scattering layer 140 farthest from the LED 200 It is 5μm. Here, in the light scattering layer manufacturing step S130, the printing process can be controlled so that the thickness of the portion of the light scattering layer 140 adjacent to the LED 200 is 1 μm, and then the thickness of the light scattering layer 140 is gradually in the form of a Gaussian distribution curve, for example. Increased so that the thickness of the portion of the light scattering layer 140 farthest from the LED 200 is finally 5 μm. Here, when the thickness of the light scattering layer 140 is less than 1 μm, a light distribution similar to the Lambertian distribution cannot be obtained. When the thickness of the light scattering layer 140 exceeds 5 μm, it is difficult to dry the printed light scattering layer 140, which is problematic.

Although the LED 200 has been described as being provided only on a single side surface of the LGP 100 according to an exemplary embodiment, the LED 200 may be provided on the opposite side surface of the LGP 100. In this case, the light scattering layer 140 may be manufactured so that the thickness of a part thereof located in the central part of the LGP 100 is the largest. That is, the thickest part of the light scattering layer 140 with a thickness of 5 μm may be provided on the central area of the LGP 100.

As described above, in the light scattering layer manufacturing step S130, the density of the light scattering particles 130 relative to the printing solution can be controlled so that as the distance from the LED 200 facing at least one surface of the side surface of the LGP 100 increases, the light scattering The density of the particles 130 relative to the printing solution gradually increases, and the thickness of the light scattering particles 130 can be controlled so as to gradually increase in the form of a Gaussian distribution curve, or when the distance from the LED 200 facing at least one surface of the side surface of the LGP 100 When the distance increases and the density of the light scattering particles 130 is controlled relative to the printing solution so as to gradually increase, the thickness of the light scattering particles 130 can be controlled so as to gradually increase. Therefore, this can prevent the problem of excessive light leaving the area adjacent to the LED 200, and obtain a light distribution similar to the Lambertian distribution (see FIG. 8).

Finally, the method of manufacturing an LGP according to an exemplary embodiment may further include a light scattering layer curing step S140 that makes the light scattering layer 140 manufactured on the entire area of the rear surface of the LGP 100 in the light scattering layer manufacturing step S130 Curing. In the light scattering layer curing step S140, an inline ultraviolet (UV) ray curing device may be used to cure the light scattering layer 140.

As shown in FIG. 2, when the light scattering layer curing step S140 is completed, the LGP 100 according to the exemplary embodiment is manufactured. That is, the LGP 100 according to an exemplary embodiment includes the LGP main body 110 in which the LED 200 is disposed adjacent to its side surface, and the light scattering layer 140 is manufactured on the entire area of the rear surface of the LGP main body 110. Here, the light scattering layer 140 includes a matrix layer 120 and a plurality of light scattering particles 130 dispersed in the matrix layer 120.

According to an exemplary embodiment, the surface of the light scattering layer 140 forms a flat surface with a surface roughness (Ra) of, for example, 100 nm or less. As the distance from the side surface of the LGP 100 on which the LED 200 is disposed increases, the thickness of the light scattering layer 140 gradually increases in the form of a Gaussian distribution curve. The thickness of the portion closest to the light scattering layer 140 of the LED 200 may be a minimum thickness of 1 μm, and the thickness of the portion farthest from the light scattering layer 140 of the LED 200 may be a minimum thickness of 5 μm.

In addition, as the distance from the side surface of the LGP 100 on which the LED 200 is disposed increases, the dispersion density of the number of light scattering particles 130 may gradually increase. Here, the light scattering particles 130 may be formed of a material having a higher refractive index than that of the light scattering layer 140. For example, the light scattering particles 130 may be formed of at least one selected from the following, but are not limited to the following: TiO ₂ , ZrO ₂ , BaTiO ₃ and SnO ₂ .

As described above, as the distance from the side surface of the LGP 100 on which the LED 200 is disposed increases, the dispersion density of the light scattering particles 130 gradually increases, the thickness of the entire area across the rear surface of the LGP 100 can be increased. The light scattering layer 140 is manufactured uniformly.

As shown in FIG. 3, as described above, the LGP 100 manufactured by the method of manufacturing the LGP according to the exemplary embodiment may be used in the lighting device 10.

The lighting device 10 according to the exemplary embodiment is an edge-emitting lighting device, which includes the LGP 100 and the LED 200 and the frame 300 as described above.

The LED 200 is provided on at least one side surface of the LGP 100. That is, when viewed from the drawings, the LED 200 may be disposed on the left side surface, the right side surface, or both the left side surface and the right side surface of the LGP 100. Here, at least one LED 200 may be provided on each side surface. In addition, the frame 300 provides a space in which the LGP 100 and the LED 200 are disposed. As shown in FIG. 3, the frame 300 may be configured to surround the entire portion of the LGP 100, except for the area irradiated by the LGP 100 through which light passes (ie, the upper part in the figure).

Here, the reflector sheet 400 may be disposed between the rear surface of the LGP 100 and the frame 300 to reflect light that has left the rear surface of the LGP 100 forward.

In addition, as shown in FIG. 4, the frame 300 may be configured to expose the front and rear surfaces of the LGP 100. That is, the frame 300 in the shape of a rectangular door frame may be coupled to the LGP 100. In this case, when the LED 200 is turned on, light is irradiated in opposite directions through the exposed front and rear surfaces of the LGP 100. When the LED 200 is turned off, the LGP 100 has a haze value below 30% and a transmittance above 50%, so that a front observer can see the image behind the lighting device 10 through the transparent LGP 100.

Comparative example 1

Prepare a glass LGP with a size of 120mm×120mm×2mm. For the light scattering layer, a white ink containing 12% by weight of TiO ₂ particles available from Atech innovations GmbH was prepared. Here, the white ink is hexamethylene diacrylate, exo-1,7,7-trimethylbicyclo[2.2.1]heptan-2-acrylate (exo-1,7,7-trimethylbicyclo[2.2 .1] hept-2-yl acrylate, benzyl acrylate, 2-methoxyethyl acrylate, and 2,4,6-trimethylbenzyl phosphine oxide (diphenyl( 2,4,6-trimethylbenzoyl) phosphine oxide). By printing on the LGP at 400×400 dpi (dots per inch), a specific area of the LGP is not printed (unprinted) and by adjusting the droplet size to 12pL to give a concentration gradient. According to the concentration gradient, the adjacent part of the LED is printed at a concentration of 10% (ie 400×400×10% = 16,000 drops per 1×1 square inch), and the part farthest from the LED is printed at a concentration of 20% .

After that, two LED strips respectively provided by twelve LEDs available from Luminus Inc. are attached to the left and right surfaces of the LGP by connecting them in series, and the final product is observed, where the power is 35V and 63mA. supply. In addition, a CS-1000 spectroradiometer (spectroradiometer) available from Minolta Co. was used to measure the brightness. Therefore, the measured average front brightness is 4100 cd/cm ² .

With reference to the image in FIG. 5, visually recognize the point where the light passes and shines. In a plurality of regions, the relatively long distance between dots exceeds 100 μm. These parts appearing in irregular positions are observed as black spots. In addition, due to the problem of the positional accuracy of the printed dots, stains are caused by the difference between a dense region and a coarse region. In addition, as shown in the light distribution diagram of FIG. 6, since the thickness of the light scattering layer (ie, the printed layer) is small, it can be seen that the light distribution is significantly spread in the lateral direction.

Comparative example 2

Printing was performed at a concentration of 30% in the area adjacent to the LED and printing at a concentration of 60% in the area farthest from the LED, with the remaining conditions controlled to be the same as in Comparative Example 1.

Referring to the line graph in FIG. 7, the line graph depicts the location-specific brightness uniformity depending on the density of the LGP manufactured in Comparative Examples 1 and 2. It can be understood that the location-specific brightness (that is, diamond ( Diamond) marking curve) has a higher uniformity than the position-specific brightness of Comparative Example 2 (ie, square marking curve).

Example 1

A board with Iris ^™ Glass having a size of 120 mm×120 mm×2 mm, available from Corning Inc., was prepared as the LGP. Cut the Iris ^TM Glass board and clean it with an inline ultrasonic cleaner. For the light scattering layer, a solution including 2% by weight of BaTiO ₃ powder was prepared. Prepare dipropylene glycol methyl ether (DPM) solution, and input and disperse the BaTiO ₃ powder together with the dispersant in the DPM solution. The resulting solution was mixed with polysiloxane so that the final content of BaTiO ₃ powder was 0.3% by weight. Afterwards, by adjusting the size of the droplets to 12pL, the mixed solution was printed on the LGP with different printing densities relative to the printing density of 800×800 dpi. Specifically, printing is performed by imparting a concentration gradient so that the adjacent part of the LED is printed at a concentration of 50% (ie, 800×800×50% = 320,000 droplets per 1×1 square inch), and 80% density (800×800×80%=512,000 drops per 1×1 square inch) to print the farthest part from the LED. Use a printed image with a printing density in a dot pattern format. After printing, a linear curing device is used to cure the printed layer. Here, a metal halide lamp is used to irradiate light with an intensity of 1 J/cm ² . The number of droplets was increased to about 30 times the number of droplets of Comparative Example 1. Therefore, the droplets are completely connected to each other, thereby forming a flat and smooth printing surface while having a thickness gradient in the printing layer. Here, a smooth surface refers to a glossy flat surface.

After that, two LED strips respectively provided by twelve LEDs available from Luminus Inc. were attached to the left and right surfaces of the LGP by connecting them in series, and the final product was observed, where the power was 39 and 498mA. supply. In addition, a CS-1000 spectroradiometer (spectroradiometer) available from Minolta Co. was used to measure the brightness. Therefore, the measured average front brightness is 14740 cd/cm ² . Since the dots are connected to each other, neither stains due to differences in printing density nor dark dots due to the spacing between droplets are observed. In addition, as shown in the light distribution diagram of FIG. 8, as the thickness of the light scattering layer (ie, the printing layer) increases, the light distribution according to the direction of the irradiated light is more similar to the Lambertian distribution. As shown in the images of FIGS. 9A and 9B, when the LED is turned off, the transparent LGP and the printed layer allow visual recognition of objects behind the LGP and the printed layer, thereby providing a transparent lighting device. When measured using a BYK-Gardner haze meter available from BYK-Gardner GmbH, the transmittance and haze values of the LGP were 87% and 15%, respectively.

The above description of the specific exemplary embodiment of the present disclosure has been presented with respect to the drawings, which is not intended to be exhaustive or to limit the present disclosure to the precise form disclosed, and obviously, the technical field of the present disclosure has Generally knowledgeable persons may make many modifications and changes in view of the above teachings.

Therefore, the scope of the present disclosure is intended not to be limited to the above-mentioned embodiments, but to be defined by the scope of the attached patent application and its equivalents.

S110: LGP preparation steps S120: Printing solution manufacturing steps S130: light scattering layer manufacturing steps S140: curing step of light scattering layer 10: Edge-emitting lighting device 100: Light guide plate (LGP) 110: LGP body 120: matrix layer 130: light scattering particles 140: light scattering layer 200: LED 300: frame 400: reflector sheet

FIG. 1 is a processing flowchart illustrating a method of manufacturing an LGP according to an exemplary embodiment;

FIG. 2 is a conceptual diagram schematically illustrating an LGP manufactured according to an exemplary embodiment;

3 and 4 are conceptual diagrams schematically illustrating a lighting device including an LGP manufactured according to an exemplary embodiment;

Figure 5 is an image obtained by observing the LGP manufactured in Comparative Example 1;

6 is a light distribution diagram of the LGP manufactured by Comparative Example 1 of the present disclosure;

FIG. 7 is a line graph showing the brightness uniformity at a specific location depending on the density of the LGP manufactured in Comparative Examples 1 and 2 of the present disclosure;

8 is a light distribution diagram of the LGP manufactured in Example 1 of the present disclosure;

9A and 9B are images showing the lighting device using the LGP manufactured by Example 1 of the present disclosure; and

10 and 11 are schematic diagrams showing related art LGPs.

Domestic hosting information (please note in the order of hosting organization, date and number) no

Foreign hosting information (please note in the order of hosting country, institution, date and number) no

S110: LGP preparation steps

S120: Printing solution manufacturing steps

S130: light scattering layer manufacturing steps

S140: curing step of light scattering layer

Claims (20)

A method of manufacturing a light guide plate used in an edge-emitting lighting device, the method includes the following steps: Prepare a light guide plate. The light guide plate includes a first surface, a second surface, and a third surface. The first surface faces a front observer and irradiates light through the first surface. The second surface and the first surface The surfaces are opposite, the third surface is connected to a surrounding portion of the first surface and a surrounding portion of the second surface to connect the first surface and the second surface, and the third surface faces a light emitting diode; and Manufacturing a light scattering layer by printing a printing solution containing light scattering particles on an entire area of the second surface, The light-scattering layer is manufactured by at least one of the following methods of controlling the printing step: a first method of controlling the printing step is such that the light-emitting diode accompanies at least one surface facing the third surface As the distance increases, the density of the light scattering particles gradually increases, and a second method of controlling the printing step is such that as the distance from the light emitting diode on at least one surface facing the third surface is As the distance increases, a thickness of the light scattering layer gradually increases. The method according to claim 1, further comprising the step of: manufacturing the printing solution before manufacturing the light scattering layer. The method according to claim 2, wherein the printing solution is produced by adding the light-scattering particles to the printing solution, so that the range of the amount of the light-scattering particles to the amount of the printing solution is by weight Count (by weight) is 0.1% to 5%. The method according to claim 2, wherein the printing solution is produced by adding the light scattering particles to the printing solution, and the light scattering particles include at least one selected from the following: TiO ₂ , ZrO ₂ , BaTiO ₃ and SnO ₂ . The method according to claim 1, wherein the first method controls the printing step so that the number of the light scattering particles per unit area changes by at least 1.2 times according to the position. The method according to claim 1, wherein the first method controls the printing so that the light scattering layer is formed to have a uniform thickness over the entire area of the second surface. The method according to claim 1, wherein the second method controls the printing so that the thickness of the light scattering layer is in the range of 1 μm to 5 μm depending on the position. The method according to claim 1, further comprising the step of: curing the light scattering layer after manufacturing the light scattering layer. A light guide plate, including: A light guide plate main body including a first surface, a second surface, and a third surface. The first surface faces a front observer and irradiates light through the first surface. The second surface and the first surface A surface opposite, the third surface is connected to a surrounding portion of the first surface and a surrounding portion of the second surface to connect the first surface and the second surface, the third surface faces a light emitting diode; and A light scattering layer manufactured on an entire area of the second surface, the light scattering layer comprising a matrix layer and a plurality of light scattering particles dispersed in the matrix layer, Wherein, as a distance from the light emitting diode on at least one surface facing the third surface increases, a thickness of the light scattering layer gradually increases. A light guide plate, including: A light guide plate main body including a first surface, a second surface, and a third surface. The first surface faces a front observer and irradiates light through the first surface. The second surface and the first surface A surface opposite, the third surface is connected to a surrounding portion of the first surface and a surrounding portion of the second surface to connect the first surface and the second surface, the third surface faces a light emitting diode; and A light scattering layer manufactured on an entire area of the second surface, the light scattering layer comprising a matrix layer and a plurality of light scattering particles dispersed in the matrix layer, Wherein, as a distance from the light-emitting diode on at least one surface facing the third surface increases, a dispersion density of the light scattering particles gradually increases. The light guide plate according to claim 10, wherein the light scattering layer is manufactured with a uniform thickness on an entire area of the second surface. The light guide plate according to claim 9 or 10, wherein a surface of the light scattering layer includes a flat surface. The light guide plate according to claim 12, wherein a surface roughness of the light scattering layer is 100 nm or less. The light guide plate according to claim 9, wherein a thickness of the light scattering layer is in the range of 1 μm to 5 μm depending on the position. The light guide plate according to claim 9 or 10, wherein the light scattering particles are formed of a material having a refractive index higher than a refractive index of the matrix layer. The light guide plate according to claim 15, wherein the light scattering particles comprise at least one selected from the following: TiO ₂ , ZrO ₂ , BaTiO ₃ and SnO ₂ . The light guide plate according to claim 9 or 10, wherein a hazing value of the light guide plate is 30% or less and a transmittance of 50% or more. A lighting device includes: The light guide plate as described in claim 9 or 10; At least one light-emitting diode, the at least one light-emitting diode is arranged to face at least one surface of the third surface, the third surface being defined as a side surface of the light guide plate; and A frame, the frame provides a space for arranging the light guide plate and the light emitting diode. The lighting device according to claim 18, wherein when the light emitting diode is turned on, light is irradiated through the first surface and the second surface, the first surface is defined as a front surface of the light guide plate, and the first surface The two surfaces are defined as a rear surface of the light guide plate, and When the light emitting diode is closed, the front observer facing the first surface can observe the second surface through the light guide plate. The lighting device according to claim 18, further comprising a reflector disposed adjacent to the second surface, and the second surface is defined as a rear surface of the light guide plate.

Images