KR20180018631A - Light unit - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a lighting device which includes: a circuit substrate; a plurality of light sources disposed on the circuit substrate; and a reflection unit disposed on the circuit substrate. The plurality of light sources penetrate the reflection unit which has a spatial region. According to the present invention, it is possible to secure stable luminosity.

Description

Lighting unit {Light unit}

The present invention relates to an illumination device using an LED as a light source, and further to a backlight unit using the illumination device, a liquid crystal display device, and a vehicle illumination device.

A device for implementing illumination by guiding light emitted from a light source is variously required in an illumination lamp, a vehicle lamp, a liquid crystal display, and the like. In such a lighting device, the technique of thinning the structure of the equipment and the structure of increasing the light efficiency are recognized as the most important technologies.

A liquid crystal display device will be described as an example in which such a lighting device operates.

1, the lighting apparatus 1 includes a substrate 20 on which a planar light guide plate 30 is disposed, and a plurality of side-type LEDs 10 (only one is shown) .

The light L incident on the light guide plate 30 from the LED 10 is reflected by the reflective sheet 40 in a fine reflection pattern provided on the bottom surface of the light guide plate 30 and is emitted from the light guide plate 30, 30 to provide light to the LCD panel 50 on the upper side.

2, a plurality of optical elements such as a diffusion sheet 31, prism sheets 32 and 33, and a protective sheet 34 are provided between the light guide plate 30 and the LCD panel 50, And a sheet may be further added.

Therefore, such a light guide plate is basically used as an essential part of such a lighting device. However, the thickness of the light guide plate itself can not be reduced due to the thickness of the light guide plate itself. In the case of a large- .

It is an object of the present invention to provide a reflective unit having an air area on the surface of a printed circuit board to improve the reflectance of light and maximize the luminance improvement, It is an object of the present invention to provide an illumination device capable of increasing the brightness without increasing the number of light sources and maximizing the adjustment and reflection efficiency of light due to a pattern design of spacers (spacers) that form air regions.

In addition, when the illumination device of the present invention is implemented as a vehicle illumination device, a light guide plate that is essential to the structure of a general illumination device is removed and a structure for guiding the light source by using a film type resin layer is formed, It is another object of the present invention to provide a reliable product which can reduce the overall thickness of the lighting apparatus and increase the degree of freedom of product design.

According to an aspect of the present invention, there is provided a lighting apparatus comprising: a circuit board; A plurality of light sources disposed on the circuit board; And a reflection unit disposed on the circuit board, the plurality of light sources passing through a reflection unit having a spatial region.

The reflection unit may include a first reflection member disposed on one side of the circuit board, and a second reflection member spaced apart from the first reflection member to form the spatial region.

The first reflecting member may include a first base member and a metal layer disposed on the first base member.

The reflection unit may include a spacing member disposed between the first reflection member and the second reflection member.

The reflection unit may include a plurality of holes.

The plurality of light sources may be disposed through the holes.

The spacing member may include a plurality of unit spacers, and the spatial region disposed within the unit spacers.

And a plurality of reflection patterns for reflecting the light emitted from the plurality of light sources on the second reflection member.

The density of the plurality of reflection patterns may increase as the distance from the light emitting direction of the light source increases.

The space region may be an air region.

The plurality of light sources may include a side light emitting device.

And a resin layer disposed on the reflection unit and covering the plurality of light sources.

And an optical pattern layer disposed on the resin layer, wherein the optical pattern layer comprises: a first substrate disposed on the resin layer; a second substrate disposed apart from the first substrate; A plurality of optical patterns disposed between two substrates, and an adhesive pattern layer disposed between the plurality of optical patterns.

The plurality of optical patterns may partially block light emitted from the plurality of light sources.

The plurality of optical patterns may be formed of a plurality of layers.

According to the present invention, a reflection unit having an air area on the surface of a printed circuit board is provided, thereby maximizing brightness improvement as well as improving the reflectance of light. The brightness can be increased without increasing the thickness of the lighting apparatus or the number of light sources. The pattern design of the spacing member (spacer) to be formed also has the effect of maximizing the control of light and the reflection efficiency.

In addition, the present invention can form an optical pattern layer having an optical pattern by patterning an adhesive material (an adhesive pattern layer) and providing an air region, thereby eliminating generation of hot spots and occurrence of dark portions in the light- The reliability between the parts to be adhered to the adhesive material can be ensured, and at the same time, the illuminating device having no significant difference in optical characteristics can be realized, and there is an effect that the parts can be arranged in a tight fashion.

In addition, it is possible to provide an air gap module having an air layer by patterning the diffuser plate or using a separate member, thereby increasing the optical characteristics of diffusion and optical uniformity of the illumination device.

Further, by forming a structure for guiding the light source by removing the light guide plate, which is essential for the structure of a general lighting apparatus, and using a film-type resin layer, the number of light sources can be reduced, the overall thickness of the lighting apparatus can be made thin, It is possible to increase the degree of freedom.

Particularly, the side-type light emitting diode can be directly mounted to directly mount the light emitting diode, thereby reducing the number of light sources and securing optical characteristics. Also, it is applicable to the structure of a flexible display by removing the light guide plate. And a diffusion plate including an air layer, so that stable emission characteristics can be secured.

1 and 2 are conceptual diagrams showing the structure of a conventional backlight unit.
FIG. 3 is a schematic cross-sectional view showing a main part of a lighting apparatus according to the present invention.
FIG. 4 shows an embodiment of the spacing member constituting the reflection unit included in the illumination apparatus according to the present invention described above with reference to FIG.
Fig. 5 shows a specific embodiment of the reflection unit described above with reference to Figs. 3 and 4. Fig.
Figure 6 illustrates another embodiment of a lighting device according to the present invention.
Figure 7 illustrates another embodiment of a lighting device according to the present invention.
8 and 9 illustrate various implementations of the optical pattern layer and the diffuser plate according to the present invention.

Hereinafter, the configuration and operation according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description with reference to the accompanying drawings, the same reference numerals denote the same elements regardless of the reference numerals, and redundant description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention provides a lighting apparatus using an LED as a light source, in which a reflection unit having a spatial region (air region) below the LED light source is disposed to improve reflectance and brightness. Particularly, in the structure of a conventional illumination device, an air gap module having an air layer is provided by patterning an optical pattern layer or a diffusion plate that implements a spatial region by patterning an adhesive material (an adhesive pattern layer) or using a separate member In particular, the present invention provides a structure capable of reducing the total thickness of the lighting device and reducing the number of light sources, in particular, by removing the light guide plate and forming it as a resin layer.

In addition, the illumination device according to the present invention is not limited to being applied to the backlight unit of the above-described liquid crystal display device. That is, the present invention is applicable to a variety of lamp devices requiring illumination, such as a vehicle lamp, a home lighting device, and an industrial lighting device. The automotive lamp can also be applied to headlights, indoors, lighting, and rear lights.

1. First Embodiment

FIG. 3 is a schematic cross-sectional view showing a main part of a lighting apparatus according to the present invention.

3, the lighting apparatus according to the present invention includes a plurality of LED light sources 130 formed on a printed circuit board 110. The LED light sources 130 are formed on the upper surface of the printed circuit board 110, And a reflection unit 120 laminated on the printed circuit board 110 with a through-hole structure. In this case, the first spatial area A1 is provided in the reflective unit 120. [ The first spatial region A1 can maximize the brightness by enhancing the reflection efficiency of the light emitted from the light source 130. [ The first spatial area A1 may be an air area.

Particularly, the reflection unit 120 includes a first reflective film 121 which is in close contact with the surface of the printed circuit board 110, and a second space 121 which is spaced apart from the first reflective film 121 to form the first spatial area A1. And a second reflective film 122 made of a transparent material. The first and second reflective films 121 and 122 are stacked on the printed circuit board, and the LED light source 130 protrudes through the hole formed on the reflective film.

The first and second reflective films 121 and 122 can be formed in a structure in which the first and second reflective films 121 and 122 are integrally pressed without using a separate adhesive or the like, The first and second reflective films 121 and 122 are spaced apart from each other so as to realize a first space region A1 in which air is received through a spacing member 123 such as a separate adhesive member It is also possible.

In this case, the first reflective film 121 may be a reflective material that reflects light, for example, a film having a metal layer such as Ag formed thereon. The second reflective film 122 may reflect light emitted from the LED, It is more preferable to use a film of a transparent material to be transmitted to the surface of the first reflection film 122 so as to be re-reflected. In particular, the light emitted from the light source 130 is transmitted through the first reflective film to be re-reflected by the second reflective film, and a reflection pattern 124 is printed on the surface of the second reflective film 122 through white printing It is more preferable to enhance the brightness by further promoting the dispersion of light. The reflective pattern 124 provided to greatly improve the reflectance of light can be printed using reflective ink containing any one of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, and PS.

Particularly, the light source of the illumination device according to the present invention can be applied to various types of light sources, and particularly preferably, it is possible to use an LED having a side-emitting type structure. In this case, In particular, it is possible to arrange the pattern so that the pattern density becomes higher as the distance from the direction of emission of the LED light source increases. In the case of implementing an LED having a side-emitting type structure, an advantage that the number of light sources can be greatly reduced can be realized.

FIG. 4 shows an embodiment of the spacing member constituting the reflection unit included in the illumination apparatus according to the present invention described above with reference to FIG.

That is, the spacing member according to the present invention can realize a first spatial region by performing a spacing function, such as a spacer member that simply separates the first reflective film and the second reflective film, or a spacer member having adhesive property, More preferably, in order to increase the efficiency of the arrangement of the first spatial region and to improve the adhesion efficiency, the spacing member may be formed by uniformly or randomly patterning the patterned structure with the structure shown in FIG. 4 .

The spacing member 123 shown in FIG. 4 has a plurality of unit spacing members 123a in which a cavity is formed therein. Inside the unit spacing member 123a, 123b may be implemented as a two-dimensional or three-dimensional structure. That is, the cross section of the unit spacer member 123a may be formed in various shapes such as a polygon, a circle, and an ellipse. In particular, as shown in the figures, in addition to the structure in which a plurality of unit spacers 123a are closely arranged, the first spacing 123b may be arranged in an irregular arrangement with respect to the first space region 123b in the unit spacing member 123a, It is also possible to realize the air space 123c in the empty space between the unit spacing members 123a.

Fig. 5 shows a specific embodiment of the reflection unit described above with reference to Figs. 3 and 4. Fig.

As described above, the reflection unit 120 according to the present invention includes a first reflection film 121 that is in close contact with a surface of the printed circuit board, and a second reflection film 122 that is spaced to face the first reflection film 122 ).

In particular, the second reflective film 122 may be formed of a transparent material such as PET, and may include a spacing member 123 for separating the first and second reflective films 121 and 122 by patterning an adhesive material. So as to form a spatial region.

Particularly, in order to maximize the reflection efficiency, the first reflection film 121 includes an optical film 126 for bonding the metal reflection layer 125 via a primer, (PSA) 127 on the substrate 128, as shown in FIG.

2. Second Embodiment

Figure 6 illustrates another embodiment of a lighting device according to the present invention.

That is, the second embodiment according to the present invention implements a structure for laminating a resin layer on the printed circuit board in the above-described first embodiment. The constitution of the present resin layer corresponds to a configuration for replacing a plate-shaped light guide plate used in a lighting apparatus of a liquid crystal display apparatus and performs a function of guiding light emitted from a light source forward.

6, the lighting apparatus according to the present invention further includes a plurality of LED light sources 130 formed on a printed circuit board 110 and a resin layer 140 for diffusing and guiding emitted light forward do.

That is, the resin layer 140 is stacked in a structure surrounding the LED light source 130, and functions to disperse light of a light source emitting in a lateral direction. That is, the function of the conventional light guide plate can be performed in the resin layer 140.

It is needless to say that the resin layer can be basically made of any resin capable of diffusing light. For example, the main material of the resin layer according to one embodiment of the present invention may be a resin having urethane acrylate oligomer as a main material. For example, a mixture of urethane acrylate oligomer, which is a synthetic oligomer, with a polymer type of polyacrylic can be used. Of course, it may further comprise a monomer mixed with a low-boiling-point diluent type reactive monomer such as isobornyl acrylate (IBOA), hydroxypropyl acrylate (HPA), or 2-hydroxyethyl acrylate (HPA). A photoinitiator -hydroxycyclohexyl phenyl-ketone) or an antioxidant.

In addition, the resin layer 140 may include a bead to increase diffusion and reflection of light. Preferably, the bead comprises 0.01 to 0.3% by weight of the total resin layer. That is, the light emitted laterally from the LED is diffused and reflected through the resin layer 140 and the bead, and can proceed in the upward direction.

This can further promote the reflection function in addition to the reflection unit 120 according to the present invention described above. Accordingly, the presence of the resin layer can reduce the thickness of the conventional light guide plate, thereby reducing the thickness of the entire product. Further, the resin layer has versatility applicable to a flexible display having a flexible material .

3. Third Embodiment

The structure of the illumination apparatus of the third embodiment in which the optical pattern layer for promoting light diffusion on the resin layer is improved in the structure of the second embodiment described above will be described.

7, in the structure described above with reference to FIG. 6, the illumination device according to the present invention includes an optical pattern layer 150 disposed on the resin layer 140 and including an optical pattern 151 As shown in FIG.

In particular, the optical pattern layer 150 may include an adhesive pattern layer 153 that forms a second space region 152 surrounding the periphery of the optical pattern. That is, the adhesive pattern layer 153 is formed by forming a spaced space (second space region) having a predetermined pattern on the optical pattern 151 and applying an adhesive material to the other portion.

That is, in the arrangement of the optical pattern layer 150 and the adhesion pattern layer 153 in the structure shown in the drawing, the optical pattern layer 150 includes the first substrate 150A and the second substrate 150B, And the second substrate 150B and the adhesive pattern layer 153 is applied to a portion other than the second space region 152 surrounding the peripheral portion of the light shielding pattern to form the first substrate 150A and the second substrate 150B, (150B).

That is, the optical pattern 151 may be formed as a light-shielding pattern formed to prevent the light emitted from the LED light source 130 from being concentrated. For this purpose, the optical pattern 151 may be formed between the optical pattern 151 and the LED light source 130 It is necessary to align them, and they are adhered to each other by using an adhensive for ensuring a fixing force after they are assembled.

The first substrate 150A and the second substrate 150B may be formed of a substrate having excellent light transmittance. For example, PET may be used. In this case, the optical pattern 151 disposed between the first substrate 150A and the second substrate 150B basically functions to prevent the light emitted from the LED light source from being concentrated, 150A) or the second substrate 150B, and the two substrates are adhered to each other by an adhesive layer for applying an adhesive material to surround the peripheral portion of the light shielding pattern . In other words, the adhesive structure of the first substrate 150A and the second substrate 150B can also function to fix the printed light-shielding pattern 151. The adhesive layer may be a thermosetting PSA, a thermosetting adhesive, or a UV cured PSA type material.

In the case where the adhesive layer 153 is formed and adhered in a pattern structure for forming the second space region 152 upon adhesion, a strong hot spot or a hot spot in which the adhesive material overlaps the light- And it is possible to increase the uniformity of the light due to the presence of the air layer.

In addition to the above-described structure, the illumination device according to the present invention having the above-described structure may include a diffusion plate 170 on the resin layer 140, and the diffusion plate 170 and the optical pattern layer 150, An air gap module 161 having a third space region 160 may be further provided. In addition, a prism sheet, a protective sheet, and the like may be additionally provided on the diffusion plate.

8 schematically illustrates the configuration of the optical pattern 151, the adhesion pattern layer 153, and the second spatial region 152 formed thereby.

When the adhesive pattern layer 153 is formed using an adhesive material so as to surround the optical pattern 151 printed on the first substrate in a specific pattern, a certain spacing space is formed and the second substrate 150B ) Is adhered, this spacing space becomes a closed structure in which an air layer is formed, and this is defined as a 'second spatial region'. The planar shape of the second space region 152 formed by the adhesion pattern layer 153 may be various shapes such as a circle, an ellipse, a rectangle, a square, and a polygon. In addition, the adhesive pattern layer may be formed using a thermosetting PSA, a thermosetting adhesive, or a UV cured PSA type material.

The optical pattern 151 may be formed as a light-shielding pattern so that a light-shielding effect can be realized in order to prevent a phenomenon that the intensity of the light is excessively strong to deteriorate optical characteristics or yellowish light. That is, the light shielding pattern can be printed using the light shielding ink so that the light is not concentrated.

The optical pattern is not a function to completely block the light but can be implemented so that the light shielding degree or the diffusing degree of the light can be controlled by one optical pattern so as to perform a function of partial shielding and diffusion of light. Furthermore, more preferably, the optical pattern according to the present invention may be implemented as a superimposed printing structure of a complex pattern. The structure of superimposed printing refers to a structure in which one pattern is formed and another pattern is printed on the pattern.

For example, in implementing the optical pattern 151, a light shielding ink containing at least one material selected from the group consisting of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and Silicon on the lower surface of the polymer film in the light- And a light-shielding pattern using a light-shielding ink containing a mixed material of Al or Al and TiO ₂ . That is, it is also possible to form a diffusion pattern on the surface of the polymer film by white printing and then form a light-shielding pattern thereon or a double structure in the reverse order. Of course, it will be obvious that the formation design of such a pattern can be variously modified in consideration of light efficiency, intensity, and shading ratio. Alternatively, it is also possible to form a light-shielding pattern, which is a metal pattern, in the middle layer in a sequential layer structure, and a triple-layer structure in which diffusion patterns are formed on the upper and lower portions, respectively. In such a triple structure, the above-mentioned materials can be selected and implemented. As a preferable example, one of the diffusion patterns is realized by using TiO ₂ having excellent refractive index, and CaCO ₃ having excellent light stability and color is used together with TiO ₂ The light diffusing pattern can be realized and the light efficiency and homogeneity can be ensured through the triple structure which realizes a light shielding pattern by using Al which is excellent in concealment. Particularly, CaCO ₃ functions to reduce the exposure of yellow light and finally realize white light. Thus, it is possible to realize light with more stable efficiency. In addition to CaCO ₃ , particles such as BaSO ₄ , Al ₂ O ₃ , It is also possible to utilize inorganic materials having a large size and a similar structure. In addition, it is preferable that the optical pattern is formed by adjusting the pattern density so that the pattern density becomes lower as the distance from the emitting direction of the LED light source decreases.

In addition, the present invention can be implemented by further including an air gap module disposed between the optical pattern layer 150 and the diffusion plate 170. FIG. 9 illustrates an embodiment of forming an air gap module disposed between the optical pattern layer 150 and the diffuser plate 170 shown in FIG.

That is, a structure having an air layer (third space region) 160 may be added between the optical pattern layer 150 and the diffusion plate 170 in the structure of the illumination device according to the present invention, The light emitted from the light source can be diffused due to the existence of the light source 160 and the uniformity of the light can be improved. The thickness of the third space region 160 is preferably 0.01 to 2 mm so as to minimize a deviation of light transmitted through the resin layer 140 and the optical pattern layer 150.

The third space region 160 may be formed by forming a structure capable of forming an air layer below the diffusion plate. The third space region 160 is defined as an "air gap module " do.

The air gap module includes both a method of forming a space region (air layer) by processing the diffusion plate itself or a structure of forming a space region by forming a separate structure below the diffusion plate. That is, as shown in FIG. 9A, a spacer 171 may be formed under the diffusion plate 170 to implement the third spatial region 160, or, as shown in FIG. 9B, And a bridge 172 that forms a third air space 160 by closely contacting the lower layer.

It is obvious that such an integral structure can be variously modified according to the patterned shape, that is, the shape of the pattern forming the space region, and accordingly, the shape of the bridge can be variously modified. Will be included. Furthermore, as in the structure shown in (c), the third spatial region 160 may be formed using a separate structure other than the method of patterning the bottom surface of the diffusion plate itself. Although the illustrated structure illustrates a structure for forming the bridge 174 with a spacer member, the gist of the present invention is that various modified embodiments capable of implementing an air layer at the bottom of the diffuser plate, including this method, It will correspond to the point.

(b) for patterning the diffusing plate itself or a structure (c) using a separate structure, as in the drawing shown in Fig. 4 (d) It is also possible to employ the structures 175 and 176 to form the spatial region 160 in a plurality of layers.

The illumination device according to the present invention may implement the arrangement of the light source 130 that emits the light L as shown in FIG. That is, the LED light source 130 may be disposed by applying a side emission LED to reduce the number of light sources.

The illumination device according to the present invention can be applied to an LCD through the following structure and operation. Referring to FIG. 7, light is emitted laterally from the side-emitting LED 130, and the emitted light is reflected and diffused by the resin layer 140 formed in place of the structure of the conventional light guide plate, , And minimize the deviation of light through the third spatial region formed at the lower portion of the diffusion plate. In particular, the presence of the reflective unit 120 according to the present invention, which is disposed between the resin layer 140 and the printed circuit board 110, can further improve the reflectivity, maximize the efficiency of light, . ≪ / RTI > In particular, in the case of the reflection unit 120 according to the present invention, the reflectance can be controlled by varying the design of the space region by patterning the adhesive material layer, and the reflectance There is also an effect of adjusting the color implementation. Further, the reflectance of the second reflective film 122 may be adjusted according to the optical characteristics and the thickness of the second reflective film 122.

In sum, the light emitted by the reflection unit 120 and the reflection pattern 124 according to the present invention has a higher reflection efficiency, and can guide light forward. The light passing through the resin layer 140 is diffused or shielded through the optical pattern 151 formed on the optical pattern layer 150. The refined light passes through the air gap module The optical characteristics are refined once again to increase the uniformity and the white light is incident on the LCD panel through the optical sheets such as the prism sheet 180 and the DBEF 190 which will be added later.

As described above, in the illumination device according to the present invention, the reflection efficiency is maximized through the structure including the spatial region of the reflection unit, the structure of the light guide plate is removed, the side light emitting type LED is used as the light source, By diffusing and reflecting light and inducing light through it, thinning and the number of light sources can be reduced. In addition, it is possible to adjust the brightness degradation and the uniformity due to the reduction of the light source with the reflective pattern, the light shielding pattern, and the space region of the air gap module, thereby improving the optical characteristics.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

110: printed circuit board
120: reflection unit
121: first reflection film
122: second reflection film
123:
124: reflection pattern
130: Light source
140: Resin layer
150: optical pattern layer
151: Optical pattern
152: second spatial area
153:
160: third spatial area
170: diffusion plate
180: prism sheet
190: DBEF

Claims (15)

A circuit board;
A plurality of light sources disposed on the circuit board; And
And a reflection unit disposed on the circuit board,
Wherein the plurality of light sources pass through a reflection unit having a spatial region.
The method according to claim 1,
Wherein the reflection unit includes a first reflection member disposed on one side of the circuit board, and a second reflection member spaced apart from the first reflection member to form the spatial region.
3. The method of claim 2,
Wherein the first reflective member comprises a first base member and a metal layer disposed on the first base member.
3. The method of claim 2,
Wherein the reflecting unit includes a spacing member disposed between the first reflecting member and the second reflecting member.
5. The method of claim 4,
Wherein the reflection unit includes a plurality of holes.
6. The method of claim 5,
Wherein the plurality of light sources are arranged to pass through the holes.
5. The method of claim 4,
Wherein the spacing member comprises a plurality of unit spacing members,
And the spatial region disposed within the unit spacing member.
3. The method of claim 2,
And a plurality of reflection patterns for reflecting upward the light emitted from the plurality of light sources on the second reflection member.
9. The method of claim 8,
Wherein the density of the plurality of reflection patterns increases as the distance from the emission direction of the light source increases.
The method according to claim 1,
Wherein the spatial region is an air region.
The method according to claim 1,
Wherein the plurality of light sources are side light emitting elements.
The method according to claim 1,
And a resin layer disposed on the reflection unit and covering the plurality of light sources.
13. The method of claim 12,
And an optical pattern layer disposed on the resin layer,
Wherein the optical pattern layer comprises:
A first substrate disposed on the resin layer, a second substrate spaced apart from the first substrate,
A plurality of optical patterns disposed between the first substrate and the second substrate,
And an adhesive pattern layer disposed between the plurality of optical patterns.
14. The method of claim 13,
Wherein the plurality of optical patterns partially block light emitted from the plurality of light sources.
15. The method of claim 14,
Wherein the plurality of optical patterns comprise a plurality of layers.

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