Patent Application
20220276428
This application claims the benefit of priority under 35 U.S.C § 119 of Korean Patent Application No. 10-2019-0072982 filed on Jun. 19, 2019, the content of which is relied upon and incorporated herein by reference in its entirety.
The present disclosure relates to a transparent light guide plate and a lighting device including the same and, more particularly, to a transparent light guide plate able to emit light through opposing surfaces and allowing for adjustment of the ratio between intensities of light exiting through the opposing surfaces, and a lighting device including the same.
In general, a light guide plate uses a phenomenon in which light from a light-emitting diode (LED) disposed to face at least one of four surfaces of a transparent plate is totally reflected within the transparent plate. A variety of methods have been used to emit an intended intensity of light from an intended location of the transparent plate. Such optimization or maximization of the intensity of exiting light has been an issue to be solved for a long period.
In general, a large amount of effort has been exerted to extract light through one surface of a transparent plate. On the other hand, it may be significantly useful to extract light through both surfaces of a transparent plate for a plurality of purposes or uses. However, in this regard, an insignificant amount of research has been performed.
Various aspects of the present disclosure provide a transparent light guide plate able to emit light through opposing surfaces and allowing for adjustment of the ratio between intensities of light exiting through the opposing surfaces, and a lighting device including the same.
In this regard, the present disclosure provides in one aspect, a transparent light guide plate including: a transparent base having a first surface, a second surface opposing the first surface, and third surfaces connecting the first surface and the second surface to each other; a light-scattering layer disposed on the first surface, and including a matrix layered on the first surface and a number of light-scattering particles dispersed in the matrix; and a dot pattern disposed on the light-scattering layer, and including at least one of a number of first dots formed from a light-absorbing material and a number of second dots formed from a light-reflective material.
In some embodiments, the matrix may have a surface roughness Ra of 1 μm or less.
In some embodiments, a central portion of the light-scattering layer may be thicker than a peripheral portion of the light-scattering layer.
In some embodiments, the matrix may contain one of polydimethylsiloxane (PDMS), silsesquioxane (SSQ), and siloxane.
In some embodiments the number of light-scattering particles may be distributed more densely in a central portion of the light-scattering layer than in a peripheral portion of the light-scattering layer
In some embodiments, the light-scattering particles may contain at least one selected from the candidate group consisting of SiO2, TiO2, BaTiO3, ZnO, ZrO2, and SnO2.
In some embodiments, the first dots may be formed from a material having a reflectance of 10% or less.
In some embodiments, the second dots may be formed from a material having a reflectance of 50% or more.
In some embodiments, the thickness of each of the light-scattering layer and the dot pattern may range from 110 nm to 20 μm.
The present disclosure also provides, in one aspect, a lighting device including: the above-described transparent light guide plate; at least one light-emitting diode facing at least one surface of the third surfaces defining side surfaces of the transparent light guide plate; a frame providing an accommodation space for the transparent light guide plate and the light-emitting diode such that the first surface and a second surface are exposed.
In some embodiments, the lighting device may emit light through both the first surface and the second surface of the transparent light guide plate when the light-emitting diode is on.
In some embodiments, the transparent light guide plate may remain transparent when the light-emitting diode is off.
In some embodiments, the haze of the transparent light guide plate may be 30% or less.
In some embodiments, the transmittance of the transparent light guide plate may be 80% or higher.
According to exemplary embodiments, the transparent light guide plate is provided by forming the light-scattering layer having the plurality of light-scattering particles dispersed therein on the transparent base, and forming the dot pattern including the plurality of dots formed from a light-absorbing material and the plurality of dots formed from a reflecting material on a portion of the surface of the light-scattering layer. When the transparent light guide plate is used in the edge-lit lighting device using LEDs as a light source, the transparent light guide plate can serve as a light guide plate enabling dual-surface lighting while allowing the ratio of intensities of light exiting through both surfaces to be easily adjusted.
In addition, the plurality of dots of the dot pattern are formed with an invisible size, such that the transparent light guide plate remains transparent when the LEDs are in a turned-off state. Accordingly, the lighting device including the transparent light guide plate can provide a variety of uses.
Hereinafter, a transparent light guide plate and a lighting device including the same according to exemplary embodiments will be described in detail with reference to the accompanying drawings.
In the following description, detailed descriptions of known functions and components incorporated in the present disclosure will be omitted in the case in which the subject matter of the present disclosure is rendered unclear by the inclusion thereof.
As illustrated in
The transparent base 110 includes a first surface 111, a second surface 112 opposing the first surface 111, and a third surface 113 connecting the first surface 111 and the second surface 112.
According to an embodiment, the first surface may define a top surface (in the drawing) of the transparent base 110, through which light emitted by light-emitting diodes (LEDs) 20 (in
According to an embodiment, the transparent base 110 may be formed from a glass material in the shape of a plate. For example, the transparent base 110 may be formed from non-alkali glass, silica glass, low-iron glass, soda-lime glass, or the like. Particularly, the transparent base 110 may be formed from a glass material, the y value in the color space of which exhibits a change of 0.03 or less when light travels to 1 m in the transparent base 110 in order not to cause a color deviation.
The light-scattering layer 120 is provided on the first surface 111 of the transparent base 110. According to an embodiment, the light-scattering layer 120 may include a matrix 121 and a number of light-scattering particles 122.
The matrix 121 is provided as a layer on the first surface 111 of the transparent base 110. Here, the surface roughness Ra of the matrix 121 may be 1 μm or less. This is because the flatness of the surface of the light-scattering layer 120 should be maintained so that the dot pattern 130 provided on the light-scattering layer 120 can maintain a suitable level of surface tension. In addition, the thickness of the matrix 121 is not specifically limited, as long as light can be scattered at that thickness. For example, the thickness of the matrix 121 may range from 100 nm to 10 μm.
According to an embodiment, the matrix 121 may contain one selected from among, but not limited to, polydimethylsiloxane (PDMS), silsesquioxane (SSQ), and siloxane.
The number of light-scattering particles 122 are dispersed in the matrix 121. According to an embodiment, the light-scattering particles 122 may contain at least one selected from the candidate group consisting of, but not limited to, SiO2, TiO2, BaTiO3, ZnO, ZrO2, and SnO2.
The light-scattering layer 120 according to the exemplary embodiment may be provided by dispersing the light-scattering particles 122 in a dispersing solution formed from a high-stability material, such as PDMS, SSQ, or siloxane, coating the first surface 111 of the transparent base 110 with the resultant mixture using spray coating or inkjet coating, and then drying or curing the mixture.
In addition, as illustrated in
In addition, as illustrated in
The dot pattern 130 is provided on the light-scattering layer 120. Here, the dot pattern 130 may be provided on the light-scattering layer 120 at a thickness ranging from 10 nm to 10 μm. According to an embodiment, the dot pattern 130 includes a number of first dots 131. In addition, the dot pattern 130 includes a number of second dots 132. In addition, the dot pattern 130 includes the number of first dots 131 and the number of second dots 132.
The number of first dots 131 are formed from a light-absorbing material. For example, the number of first dots 131 may be formed from a material having a reflectance of 10% or less. For example, the number of second dots 132 may be formed from a material having a reflectance of 50% or more. As illustrated in
In the transparent light guide plate, the number of first dots and the number of second dots may be spaced apart from or overlap the adjacent dots. For example, in a case in which a dot pattern only includes first dots, the first dots may be spaced apart from or overlap the adjacent dots. (That is, i) all of the first dots may be spaced apart from the adjacent dots, ii) all of the first dots may overlap the adjacent dots, or iii) some of the first dots may be spaced apart from the adjacent dots, while the other first dots may overlap the adjacent dots. The same will be applied to the following examples.) For example, in a case in which a dot pattern only includes second dots, the second dots may be spaced apart from or overlap the adjacent dots. For example, in a case in which a dot pattern includes first dots and second dots, the first dots and the second dots may be spaced apart from or overlap the adjacent dots.
As illustrated in electron microscope images in
In a light guide plate of the related art fabricated by periodically attaching light-scattering pattern elements having a relatively-large size of several millimeters to a transparent plate, a diffuser is required to be attached to the transparent plate. In contrast, according to the present disclosure, the diffuser of the related art can be removed, since the dot pattern 130 cannot be visually recognized.
As illustrated in
The lighting device 10 according to the exemplary embodiment includes the above-described transparent light guide plate 100, the LEDs 20, and a frame 30.
The LEDs 20 may be disposed to face at least one surface of the third surfaces 113 defining side surfaces of the transparent light guide plate 100. That is, the LEDs 20 may be disposed to face the left side surface, the right side surface, or both the left and right side surfaces of the transparent light guide plate 100 in the drawing. Here, at least one of the LEDs 20 may be disposed adjacent to each of the side surfaces.
The frame 30 provides a mounting space for the transparent light guide plate 100 and the LEDs 20. Here, according to an embodiment, the frame 30 is disposed to expose both the first surface 111 and the second surface 112 of the transparent light guide plate 100 in order to enable dual-surface lighting. In this regard, the frame 30 may be shaped to enclose the peripheral portions of the transparent light guide plate 100.
Referring to images in
In addition, in the lighting device 10, when the LEDs 20 are in a turned-off state, the transparent light guide plate 100 remains transparent. As a result, for example, a viewer on the side of the first surface 111 may recognize an image behind the lighting device 10 through the transparent light guide plate 100.
In order to realize dual-surface lighting when the LEDs 20 are in a turned-on state and realize the transparent state when the LEDs 20 are in a turned-off state, the hazing of the transparent light guide plate 100 may be 30% or less, and the transparency of the transparent light guide plate 100 may be 80% or higher. The haze of the transparent light guide plate 100 in
Hereinafter, the transparent light guide plate according a relative example will be described with reference to
As illustrated in
However, the process of providing the patterns with an invisible size, e.g. ranging from about 10 μm to about 40 μm overlap, is especially difficult, and expensive equipment is required for such a process.
Even in the case of inkjet coating in which dispensing locations can be accurately controlled, it is impossible, in terms of probability, to eject all droplets necessary for coating to the same locations two times in a row to make the patterns overlap, even in the case that the transparent base 110 is maintained in a fixed position. In addition, in a case in which the size of droplets is set to be tens of micrometers (μm) or less to make the pattern visually unrecognizable for an aesthetic effect, it is more impossible in terms of probability.
In a case in which the light-scattering pattern 220 and the reflective pattern (or the absorbing pattern) 230 are misaligned (
The foregoing descriptions of specific exemplary embodiments of the present disclosure have been presented with respect to the drawings and are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed herein, and many modifications and variations would obviously be possible for a person having ordinary skill in the art in light of the above teachings.
It is intended, therefore, that the scope of the present disclosure not be limited to the foregoing embodiments, but be defined by the Claims appended hereto and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2019-0072982 | Jun 2019 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/036952 | 6/10/2020 | WO |
