KR102855363B1 - Light source module - Google Patents

Abstract

The present embodiment relates to a light source module. According to one aspect, the light source module includes: a printed circuit board made of a transparent material; a light source disposed on a lower surface of the printed circuit board; a light guide layer accommodating the printed circuit board; a reflective layer disposed under the light guide layer; and a diffusion layer disposed on an upper surface of the light guide layer, wherein the light guide layer includes a first light guide layer disposed under the printed circuit board and a second light guide layer disposed over the printed circuit board, and a thickness of the first light guide layer is greater than a thickness of the second light guide layer.

Description

Light source module

This embodiment relates to a light source module.

Light source modules utilizing various light sources used in electronic devices are implemented in a way that increases light efficiency by utilizing appropriate light sources according to the characteristics of each electronic device.

Recently, light source modules used in these electronic devices can be applied in various ways, such as backlight units applied to flat panel displays, interior lights used in indoor environments, headlights, fog lights, backlights, sidelights, license plates, taillights, brake lights, turn signals, and emergency flashers installed on the exterior of a vehicle, vehicle lamps that implement various images for V2V and V2C on the exterior of a vehicle, vehicle lamps for hidden lighting that implement light but are not exposed because they are formed as an integral part of the vehicle body, and interior lights installed inside a vehicle.

Meanwhile, efforts to improve the luminous efficiency of LEDs are ongoing, from chip to packaging. For example, at the packaging stage, efforts are being made to create a thermally stable structure by applying relatively high currents using materials with high heat dissipation efficiency, such as heat sinks. Efforts are also being made to optimize the package's optical structure and characteristics to increase light extraction efficiency.

However, while many of these efforts have achieved some degree of effectiveness at the laboratory level, there are significant difficulties in applying them to actual manufacturing processes.

The present invention has been proposed to improve the above-mentioned problems, and provides a light source module having a high light efficiency by improving the structure and capable of eliminating hot spots for a surface light source.

In addition, the purpose is to provide a light source module that can improve uniformity for a surface light source while having a smaller thickness than existing vehicle lamps by improving the structure.

A light source module according to the present embodiment includes: a printed circuit board made of a transparent material; a light source disposed on a lower surface of the printed circuit board; a light guide layer accommodating the printed circuit board; a reflective layer disposed under the light guide layer; and a diffusion layer disposed on an upper surface of the light guide layer, wherein the light guide layer includes a first light guide layer disposed under the printed circuit board and a second light guide layer disposed over the printed circuit board, and a thickness of the first light guide layer is greater than a thickness of the second light guide layer.

In this embodiment, since the light source is placed on the lower surface of the printed circuit board, the optical path within the light source module is increased compared to the conventional method, thereby increasing the advantage of light uniformity. That is, since the light source is placed on the upper and lower surfaces of the printed circuit board, the surface opposite to the surface facing the emission surface, hot spots can be eliminated, and the thickness of the diffusion layer can also be formed thinner compared to the conventional method.

Figure 1 is a cross-sectional view of a light source module according to an embodiment of the present invention.
Figure 2 is a cross-sectional view showing the state in which light is irradiated from a light source module according to an embodiment of the present invention.
Figure 3 is a diagram showing changes in brightness according to optical patterns.
Figure 4 is a graph showing changes in brightness depending on the distance from a light source according to an embodiment of the present invention.
Figures 5 and 6 are graphs measuring the uniformity of light that changes according to the thickness of the front and back parts.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

However, the technical idea of the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

In addition, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “A and/or at least one (or more) of B, C,” it may include one or more of all combinations that can be combined with A, B, and C.

Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are intended only to distinguish one component from another, and are not intended to limit the nature, order, or sequence of the component.

And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

Additionally, when it is described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Also, when it is expressed as "above" or "below", it can include the meaning of the downward direction as well as the upward direction based on one component.

FIG. 1 is a cross-sectional view of a light source module according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a state in which light is irradiated from a light source module according to an embodiment of the present invention, FIG. 3 is a diagram showing changes in brightness according to an optical pattern, FIG. 4 is a graph showing changes in brightness according to a distance from a light source according to an embodiment of the present invention, and FIGS. 5 and 6 are diagrams measuring the uniformity of light that changes according to the thickness of the front and rear parts.

Referring to FIGS. 1 and 2, a light source module (100) according to an embodiment of the present invention may include a printed circuit board (110), a light source (120), a light guide layer (130), a reflective layer (140), and a diffusion layer (150).

The printed circuit board (110) is formed in a plate shape, and the light source (120) can be mounted on the lower surface. The printed circuit board (110) can be formed of a transparent material. The printed circuit board (110) can be formed of a film-shaped glass or resin material. The material of the printed circuit board (110) can include at least one of PET, PEN, PI, and PC.

An electrode for electrically connecting the light source (120) may be placed on the lower surface of the printed circuit board (110), and the electrode may also be formed of a transparent material. The transparent electrode may be formed of a mesh made of ITO or Cu/Ag material.

The light source (120) may be arranged on the lower surface of the printed circuit board (110). The light source (120) may include a light emitting diode (LED). The light sources (120) may be provided in multiple numbers and may be arranged to be spaced apart from each other on the lower surface of the printed circuit board (110). The light sources (120) may provide light by driving. The light source (120) may be a direct-type light emitting diode. Alternatively, the light emitting element (120) may be a side view type light emitting diode. The light source (120) may be in the form of an LED chip or an LED PKG.

The above reflective layer (140) may be disposed on the lower side of the printed circuit board (110). The reflective layer (140) may be disposed a predetermined distance from the lower surface of the printed circuit board (110). The reflective layer (140) may reflect light generated from the light source (120) upward. Since the printed circuit board (110) is formed of a transparent material, the light generated from the light source (120) may be irradiated downward and then reflected by the reflective layer (140) to be transmitted upward of the printed circuit board (110). The reflective layer (140) may be formed of a metal material. A plurality of reflective patterns (not shown) may be disposed on the upper side of the reflective layer (140), that is, on the surface facing the light source (120). The above plurality of reflective patterns (not shown) can be arranged through a process of printing white ink on the upper portion of the reflective layer, and the above plurality of reflective patterns (not shown) can increase the amount of light generated from the light source (120) reflected upward, thereby increasing the brightness of the light emitted from the light source module (100). In addition, depending on the type of the light source (120), in the case of a direct-type light-emitting diode, light is concentrated at the center portion of the light source (120), so the above plurality of reflective patterns (not shown) can be formed so that the density decreases as they get farther away from the light source (120).

The above light guide layer (130) accommodates the printed circuit board (110) therein and can form a path for light generated from the light source (120). The light guide layer (130) may be an air gap formed between the diffusion layer (150) and the reflective layer (140), which will be described later. Alternatively, the light guide layer (130) may be a plate or mold shape formed of a resin or a resin material, and the light guide layer (130) disposed below or above the printed circuit board (110) may be formed of a resin material having a different refractive index or may be formed of a resin material having a different component. The thickness of the light guide layer (130) may be formed thicker than the thickness of the reflective layer (140) or the diffusion layer (150).

The light guide layer (130) may be divided into a first light guide layer (132) and a second light guide layer (134) by the printed circuit board (110). The first light guide layer (132) may be disposed on the lower side of the printed circuit board (110), and the second light guide layer (134) may be disposed on the upper side of the printed circuit board (110). The thickness (T1) of the first light guide layer (132) may be formed to be thicker than the thickness (T2) of the second light guide layer (134). Light generated from the light source (120) may be reflected from the reflection layer (140) through the first light guide layer (132), and then sequentially pass through the first light guide layer (132), the printed circuit board (110), the second light guide layer (134), and the diffusion layer (150) to be irradiated to the irradiated area. The upper surface of the diffusion layer (150) may be an emission surface through which light within the light-emitting module (100) is emitted.

In this embodiment, the light guide layer (130) is exemplified as including a first light guide layer (132) and a second light guide layer (134) that are vertically partitioned by the printed circuit board (110), but the light guide layer (130) may include only the first light guide layer (132). In this case, the diffusion layer (150) may be formed on the upper surface of the first light guide layer (132) or the upper surface of the printed circuit board (110).

The above diffusion layer (150) may be placed on top of the light guide layer (130). The diffusion layer (150) may diffuse light from the light source (120) emitted to the outside. The material of the diffusion layer (150) may include resin or a transparent film.

A lens-shaped optical pattern (152) may be formed on the upper surface of the diffusion layer (150). The optical pattern (152) may be implemented through a plurality of protrusions, and the shapes of the plurality of protrusions may include a hemisphere, a portion of a hemisphere, a cone, or a pyramid. Light from the light source (120) may be irradiated to the irradiated area without light loss through the diffusion layer (150).

According to the structure as described above, the light source (120) is arranged on the lower surface of the printed circuit board (110), that is, the emission direction of the light source module (100) and the emission direction of the light source (120) are configured to be opposite to each other, so that the optical path of the light source (120) in the light source module (100) increases compared to the prior art, and thus there is an advantage in that the light uniformity increases. That is, the light source (120) is arranged on the opposite surface of the upper and lower surfaces of the printed circuit board (110) from the surface facing the emission surface of the light source module (100), so that hot spots can be eliminated, and the uniformity of the light source module (100) can be improved, while also having the advantage in that the thickness of the light guide layer (130) can be formed thinner compared to the prior art.

Referring to Fig. 3, it can be confirmed that the brightness and luminance values change depending on the shape of the optical pattern (152).

For example, as the size of each of the plurality of protrusions within the optical pattern (152) increases, the brightness and luminance of the light emitted from the light source module (100) may increase. In addition, as the spacing between the plurality of protrusions within the optical pattern (152) decreases, the brightness and luminance of the light emitted from the light source module (100) may increase.

That is, when Case 2, Case 5, and Case 6 are compared with reference to the table of FIG. 3, the spacing between the plurality of protrusions within the optical pattern (152) is the same at 264 um, but the sizes are different. At this time, since the brightness and luminance are the largest in Case 6, it can be seen that as the size of the protrusion increases, the brightness and luminance increase. In addition, when Case 2, Case 3, and Case 4 are compared, the spacing between the plurality of protrusions within the optical pattern (152) is different, and the size of the protrusion is the same at 60 um with a radius based on a hemispherical shape. At this time, since the brightness and luminance are the largest in Case 4, it can be seen that as the spacing between the plurality of protrusions decreases, the brightness and luminance increase.

In order to satisfy the required luminance and brightness of the light source emitted from the light source (120), the radius of the protrusion may be formed to be 45 um to 75 um or less. In addition, the interval between adjacent protrusions may be formed to be 176 um to 264 um or less. Here, the interval between adjacent protrusions may be defined as the straight-line distance between the centers of the protrusions. Therefore, in order to increase the luminance and brightness of the light source module (100), the larger the volume of the optical pattern (152) per unit area based on the upper surface of the diffusion layer (150), the better.

Referring to Fig. 4, it can be confirmed that the brightness of the light emitted from the emission surface of the light source module (100) decreases as it moves away from the center. At this time, when the area horizontally overlapping with the light source (120) is defined as the center (0), the light emitted from the center (0) can have the highest brightness. In addition, in the case of the LED light source module (100) according to the present embodiment, it can be confirmed that the light is emitted uniformly as the uniformity defined as the value of the minimum brightness of the emitted light divided by the maximum brightness satisfies 87.3%.

In FIGS. 5 and 6, the first light guide layer (132) is defined as the front side and the second light guide layer (134) is defined as the rear side based on the printed circuit board (110), and the light uniformity and brightness values according to the thickness (T1) of the front side or the thickness (T2) of the rear side are shown.

As illustrated, it can be confirmed that the rear portion has high optical uniformity when the thickness (T2) is 1 mm, and the front portion has high optical uniformity when the thickness (T1) is 2.5 mm. Accordingly, it is preferable that the thickness (T1) of the first optical guide layer (132) is formed to be 2 mm to 3 mm or less, and the thickness (T2) of the second optical guide layer (134) is formed to be 0.5 mm to 1.5 mm or less. That is, in order to implement uniformity of 87% or more, it can be seen that the thickness (T1) of the front portion should be 2.4 mm to 3.0 mm, and the thickness (T2) of the rear portion should be 0.9 mm to 1.1 mm. Therefore, it is preferable that the thickness (T2) of the rear portion be 30% to 46% or less compared to the thickness (T1) of the front portion. In order to achieve the highest brightness at this time, the thickness (T1) of the front part is best when it is 2.5 mm, and therefore the thickness (T2) of the rear part is best when it is 36% to 44% of the thickness (T1) of the front part.

Although all components constituting the embodiments of the present invention have been described above as being combined or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the purpose of the present invention, all components may be selectively combined and operated one or more times. In addition, terms such as "include," "comprise," or "have" described above, unless specifically stated to the contrary, mean that the corresponding component may be inherent, and therefore should be interpreted as including other components rather than excluding other components. All terms, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as terms defined in a dictionary, should be interpreted as being consistent with the contextual meaning of the related technology, and shall not be interpreted in an ideal or excessively formal sense, unless explicitly defined in the present invention.

The above description is merely an illustrative description of the technical idea of the present invention, and those skilled in the art will appreciate that various modifications and variations may be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims (8)

Printed circuit board made of transparent material;
A light source arranged on the bottom of the printed circuit board;
An optical guide layer accommodating the above printed circuit board;
A reflective layer disposed below the optical guide layer; and
Including a diffusion layer disposed on top of the optical guide layer,
The above optical guide layer includes a first optical guide layer disposed below the printed circuit board and a second optical guide layer disposed above the printed circuit board,
A light source module in which the thickness of the first light guide layer is greater than the thickness of the second light guide layer.
In the first paragraph,
An optical pattern is formed on the upper surface of the above diffusion layer,
The above optical pattern is a light source module including a plurality of protrusions having a hemispherical shape.
In the second paragraph,
The radius of each of the above multiple protrusions is 45 um to 75 um or less,
A light source module wherein the spacing between the plurality of protrusions is 176 um to 264 um or less.
In paragraph 1,
The above light guide layer is a light source module that is an air gap formed between the lower surface of the diffusion layer and the upper surface of the reflection layer.
In the first paragraph,
The material of the above light guide layer includes resin or resin,
A light source module in which the first light guide layer and the second light guide layer include a resin or resin material having different refractive indices.
In the first paragraph,
A light source module including a transparent electrode that electrically connects the light source to the printed circuit board.
In any one of claims 1 to 6,
The thickness of the first optical guide layer is 2 mm to 3 mm or less,
A light source module wherein the thickness of the second light guide layer is 0.5 mm to 1.5 mm or less.
In paragraph 7,
A light source module in which the thickness of the second light guide layer is 30% to 46% of the thickness of the first light guide layer.