Light-emitting device assembly and vehicle headlights with the same

Abstract

Light-emitting device assembly (100; 102) comprising: a substrate (120; 220); a plurality of light-emitting device chips (110; 210) arranged linearly and spatially separated from one another on the substrate (120; 220); and a plurality of wavelength conversion units (130; 230) on surfaces of the plurality of light-emitting device chips (110; 210), wherein the plurality of wavelength conversion units (130; 230) each have regions extending over regions between the plurality of light-emitting device chips (110; 210), wherein each of the plurality of wavelength conversion units (110; 210) has: a longer side extending in a first direction in which the light-emitting device chips (110; 210) are arranged;and a shorter side that is shorter than the longer side, wherein shorter sides of wavelength conversion units adjacent in the first direction of the plurality of wavelength conversion units (110; 210) are spaced apart from each other, wherein side faces of the shorter sides are exposed, wherein each of the plurality of wavelength conversion units (130; 230) has several phosphor layers (131, 132, 133; 134, 135; 231, 232, 233; 234, 235), and wherein the phosphor layers (131, 132, 133; 134, 135; 231, 232, 233; 234, 235) are stacked sequentially according to the lengths of wavelengths such that a light-emitting phosphor layer with a shorter wavelength is located at one bottom and a Light-emitting phosphor layers with a longer wavelength are arranged on a surface.

Description

BACKGROUND Area The present invention relates to a light-emitting device assembly and a vehicle headlight which uses a light-emitting device assembly as a light source. Description of related technology A light source that uses an incandescent bulb can generally be used as a light source for a headlight installed in a vehicle. An incandescent bulb is a light source in which a non-flammable gas is stored in a vacuum within the bulb, and a filament, such as one made of tungsten, is electrothermally heated to produce the light emitted from it. However, light bulb sockets generally have a relatively short lifespan and low impact resistance. Consequently, there has recently been a great deal of effort and interest in developing a light source such as a light-emitting diode (LED) that can operate at low voltage and that can exhibit excellent durability, a long lifespan, and a simple structure, while also being available in various shapes. A vehicle headlight that uses an LED can be designed to produce a large amount of light in terms of its properties, and consequently, a plurality of LED chips can be arranged continuously to form a light source with high luminance. However, when multiple LED chips are arranged, a rectangular interruption in the light distribution properties can occur, leading to a disruption in obtaining continuous light. This can result from a structural problem where light is separated by a space between LED chips, causing it to appear non-continuous. Furthermore, WO 2012 / 111292 A1 discloses a light-emitting module comprising: a substrate; light-emitting semiconductor elements mounted on the substrate and arranged in a matrix; a layer of fluorescent material positioned opposite the light-emitting surfaces of the light-emitting semiconductor elements; and light-shielding sections positioned to surround the light-emitting surfaces of at least some of the light-emitting semiconductor elements. EP 1 995 780 A1 discloses a light-emitting device comprising a combination of multiple LED chips and a phosphor layer. The multiple light-emitting semiconductor devices (LED chips) are arranged with a gap between them, and the phosphor layer is formed on their upper surface to bridge the gaps between the LED chips. The phosphor layer can have a uniform thickness; however, it is preferably thinner over the gaps between the LED chips than on the top surface of the LED chips. The phosphor layer is formed continuously on the upper surface of the chip arrangement, without any phosphor layer being present between the chips. US Patent 2011 / 0121731A1 discloses a light-emitting module comprising: a plurality of light-emitting semiconductor elements; a substrate supporting the arranged plurality of light-emitting semiconductor elements; and a plate-shaped wavelength-conversion component positioned to face the light-emitting surfaces of the multiple light-emitting semiconductor elements, which converts the wavelength of the light emitted by the light-emitting semiconductor element. A phosphor layer includes a shielding section formed at the boundary between the respective areas facing the light-emitting surfaces of the adjacent light-emitting semiconductor elements. SUMMARY Exemplary embodiments relate to a light-emitting device assembly and / or a vehicle headlight which uses a light-emitting device assembly as one of its light sources. In the case of a light-emitting device and a vehicle headlight that uses a light-emitting device assembly with a light-emitting device as a light source, a vehicle headlight with excellent light distribution characteristics that allow light to be obtained without a rectangular interruption may be desired. A light-emitting device assembly according to the invention is the subject of claim 1, while a vehicle headlight according to the invention is the subject of claim 5. Further developments are the subject of dependent patent claims. BRIEF DESCRIPTION OF THE DRAWINGS The above and further aspects, features, and advantages of exemplary embodiments will be more clearly understood through the following detailed description of non-restrictive embodiments, as illustrated in the accompanying drawings. The drawings are not necessarily to scale; instead, the emphasis is placed on the principles of exemplary embodiments. In the drawings is / are: Fig. 1 a schematic view illustrating a configuration of a vehicle headlight according to exemplary embodiments; Fig. 2 a perspective exploded view of the vehicle headlight illustrated in Fig. 1; Fig. 3 a cross-sectional view illustrating the vehicle headlight illustrated in Fig. 2; and Fig. 4 a top view of a light-emitting device assembly in a vehicle headlight according to exemplary embodiments.Figures 5A to 5C are cross-sectional views of light-emitting device assemblies along a line VV' of Figure 4 according to exemplary embodiments; Figure 6 is a top view of a light-emitting device assembly in a vehicle headlight according to an exemplary embodiment; Figures 7A to 7C are cross-sectional views of light-emitting device assemblies along a line VII-VII' of Figure 6 according to exemplary embodiments; Figure 8A is a diagram showing a light intensity when a wavelength conversion unit is formed that has the same size as that of a light-emitting device chip; Figure 8B is a diagram showing a light intensity when a wavelength conversion unit is formed on a surface of a light-emitting device chip according to exemplary embodiments; FigureFigure 9A is a photograph showing light emitted by the light-emitting device chip when the wavelength conversion unit is configured to be the same size as that of a light-emitting device chip; and Figure 9B is a photograph showing light emitted by the light-emitting device chip when the wavelength conversion units are formed on a surface of a light-emitting device chip according to exemplary embodiments. Herein, Figure 5B refers to the light-emitting device assembly according to claim 1. DETAILED DESCRIPTION Exemplary embodiments will now be described in more detail with reference to the accompanying drawings, which show some exemplary embodiments. Exemplary embodiments can, however, take many different forms; these exemplary embodiments are provided here in such a way that this disclosure is thorough and complete for the average person skilled in the art, and that it covers the scope of exemplary embodiments. For clarity, the thicknesses of layers and areas are exaggerated in the drawings. Identical reference numerals in the drawings denote identical elements, and consequently, their descriptions can be omitted. It is understood that when an element is described as "connected to" or "coupled with" another element, it may be directly connected or coupled to that other element, or there may be elements in between. Conversely, when an element is described as "directly connected to" or "directly coupled with" another element, there are no elements in between. When used here, the term "and / or" includes any and all combinations of one or more of the related items listed. Other words used to describe the relationship between elements should be understood in a similar way (for example, "between" versus "immediately between," "adjacent" versus "immediately adjacent," "on" versus "immediately upon," etc.). It is understood that, although the terms "first," "second," etc., may be used here to describe different elements, components, areas, layers, and / or sub-areas, these elements, components, layers, and / or sub-areas are not intended to be limited by these terms. These terms are used only to distinguish one element, component, area, layer, or sub-area from another. Consequently, a first element, component, area, layer, or sub-area described below may be referred to as a second element, component, area, layer, or sub-area without deviating from the teaching of exemplary embodiments. Spatially related terms, such as "lower," "below," "underneath," "lower," "above," "upper," and the like, can be used here to facilitate description and to describe an element or the relationship of a feature to another element or feature, as illustrated in the figures. It is understood that these spatially relative terms are intended to encompass different orientations of the device in operation, in addition to the orientation depicted in the figures. For example, if the device is rotated in the figures, elements described as "below" or "underneath" other elements or features would then be oriented "above" those other elements or features. Consequently, the exemplary term "below" can delimit both an upward and a downward orientation.The device may be oriented differently (rotated by 90 degrees or in another orientation) and the spatially relative terms used here may be interpreted accordingly. The technical language used here is intended solely to describe specific embodiments and does not aim to limit the exemplary embodiments. As used here, the singular forms "a / an / an" and "the" are meant to include the plural forms unless the context clearly indicates otherwise. Furthermore, it is understood that the terms "he / she / it indicates" and / or "indicating," when used here, signify the presence of certain features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.Terms such as "at least one of" when they precede a list of items change the entire list of items and do not change the individual items in the list. Exemplary embodiments are described herein with reference to cross-sectional illustrations, which are schematic representations of idealized embodiments (and intermediate structures) of exemplary embodiments. Consequently, deviations from the shapes of the illustrations are to be expected due to, for example, manufacturing techniques and / or tolerances. Therefore, exemplary embodiments should not be considered as limiting to the specific shapes of the areas illustrated herein, but rather are intended to encompass variations in shape that result, for example, from manufacturing. Consequently, the areas illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shape of any area of ​​a device, nor are they intended to limit the scope of exemplary embodiments. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as they would normally be understood by an average person skilled in the art to whom this inventive idea relates. Furthermore, it is understood that terms such as those defined in standard dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and / or the present description, and are not to be understood in an idealized and overly formal sense unless explicitly defined as such herein. Fig. 1 is a schematic view illustrating a configuration of a vehicle headlight according to exemplary embodiments. Fig. 2 is a perspective exploded view of a vehicle headlight illustrated in Fig. 1. Fig. 3 is a cross-sectional view illustrating the vehicle headlight illustrated in Fig. 2. With reference to Fig. 1, Fig. 2 to Fig. 3 according to exemplary embodiments, a headlight 10 for a vehicle can have a light-emitting device assembly 100, a reflection unit 200, and a lens cover unit 300, and can further have a heat dissipation unit 400 that conducts heat generated by the light-emitting device assembly 100 to the outside. As illustrated in Fig. 1, a plurality of headlights 10 can be installed for a vehicle and a reflecting mirror 11 can be formed such that it is adjacent to the headlights 10 for a vehicle in order to reflect light emitted by the headlights 10 forwards and to the sides of the vehicle. The light-emitting device assembly 100 can be mounted on an upper area of ​​the heat dissipation unit 400 and connected to an external energy source to serve as a light source that emits light when energy is supplied to it. A structure of a light-emitting device assembly 100 of a vehicle headlight according to exemplary embodiments will be described in detail with reference to Figs. 4, 5A to 5C, 6 and 7A to 7C. First, a light-emitting device assembly 100, in which a light-emitting device chip 110 is installed on a substrate 120, will be described with reference to Figs. 4 and 5A to 5C. Figure 4 is a top view of a light-emitting device assembly in a vehicle headlight according to exemplary embodiments. Figures 5A to 5C are cross-sectional views of light-emitting device assemblies according to exemplary embodiments, taken along a line VV' from Figure 4. With reference to Figures 4 and 5A, the light-emitting device assembly 100 can comprise at least one light-emitting device chip 110, a substrate 120 on which the light-emitting device chip 110 is mounted, and a wavelength conversion unit 130 formed on a surface of the light-emitting device chip 110. The wavelength conversion unit 130 can comprise a wavelength conversion material and be configured to convert a wavelength of light generated by the light-emitting device chip 110 into one or more different wavelengths of light. The light-emitting device chip 110 can be a semiconductor device type deposited on the substrate 110 and configured to emit light of a specific wavelength by means of externally supplied energy. As shown in Fig. 4 and Fig. 5A, a plurality of light-emitting device chips 110 are arranged linearly on a bottom surface of the substrate 120. In this case, the light-emitting device chip 110 can be configured as a combination of light-emitting device chips emitting blue light (B), red light (R), and green light (G) in a series array to emit white light (W). However, exemplary embodiments are not limited to this, and light-emitting device chips emitting the same light can be configured similarly. If the light-emitting device chip 110 is a blue-light (B) emitter, it can generate white light using the wavelength conversion unit 130 (described later).The light-emitting device chip 110 can emit light in different colors such as red light (R), green light (G), orange light (A) and the like, and of course light in different colors such as red light (R), green light (G), orange light (A) can be realized by the wavelength conversion unit 130. The light-emitting device chip 110 can be electrically connected to an electrode connection formed on the substrate 110 via a metal wire according to a wire connection scheme, or it can be electrically connected via an electrode connection formed on the substrate 110 according to a flip-chip bonding scheme. Exemplary embodiments are not limited to these. The light-emitting device assembly 100 has the wavelength conversion unit 130 with an area extending to a region between the majority of light-emitting device chips 110, arranged linearly on surfaces of light-emitting device chips 110. The wavelength conversion unit 130 serves to convert a wavelength of light emitted by the light-emitting device chip 110 into another wavelength and can be formed as a thin film on a light-emitting surface of the light-emitting device chip 110. Since the wavelength conversion unit 130 is designed as a thin film, it can have a relatively uniform shape and thickness, thereby reducing (and / or minimizing) chromaticity deviations of light in a light emission direction and also reducing different chromaticity distributions between devices. Meanwhile, the wavelength conversion unit 130, in order to perform the light conversion function, can contain a wavelength conversion material such as phosphors or quantum dots. In this case, the wavelength conversion unit 130 can have a plate structure (for example, a ceramic conversion unit) formed solely from a wavelength conversion material, a layered structure in which a wavelength conversion material is dispersed in a silicon resin, and the like. The wavelength conversion unit 130 can, for example, be a phosphor layer. The wavelength conversion unit 130 is configured such that it is longer than one side length of the light-emitting device chip 110 in the direction in which the light-emitting device chips 110 are arranged to cover an area between them. Specifically, if the light-emitting device chips 110 are arranged linearly in a horizontal direction on the underside of the substrate 120, the wavelength conversion unit 130 is configured such that it is longer than one length of the horizontal side of the light-emitting device chip 110. For example, if the light-emitting device chips 110 have a size of approximately 1 × 1 mm, the wavelength conversion unit 130 can have a size of approximately 2 × 1 mm.The wavelength conversion unit 130 can therefore have a rectangular shape with one longer side oriented in the direction in which the light-emitting device chips 110 are arranged. Specifically, the longer side of the wavelength conversion unit 130 is longer than one side of the light-emitting device chip 110. A shorter side is similar in length to one side of the light-emitting device chip 110. Alternatively, the wavelength conversion unit 130 can be adjacent to another wavelength conversion unit 130 formed on the surface of a neighboring light-emitting device chip. If the wavelength conversion unit 130 is formed such that it has an area extending to a region between the plurality of light-emitting devices, it can convert a wavelength of light that is output to a side direction of the light-emitting device chip, reducing a dark area formed between the light-emitting device chips. Consequently, a problem can be solved where emitted light is considered to be interrupted rather than continuous due to a space between chips, because wavelength conversion units are coated only on the surfaces of light-emitting device chips arranged sequentially in the related light-emitting device assembly. Fig. 5B illustrates a wavelength conversion unit with a multilayer structure (the wavelength conversion unit is illustrated as having a structure with three layered layers, however exemplary embodiments are not limited to this). In the case where the wavelength conversion unit 130 has a multilayer structure formed by layers of a plurality of layers, the layered layers of the wavelength conversion unit 130 can contain the same wavelength conversion material or different wavelength conversion materials. In the case where the layered multilayers of the wavelength conversion unit contain 130 phosphors as wavelength conversion materials, the phosphor layers can be layered sequentially according to the lengths of wavelengths such that a light-emitting phosphor layer with a shorter wavelength is arranged at a bottom and a light-emitting phosphor layer with a longer wavelength is arranged at a surface. If, for example, the light-emitting device chip 110 is a UV light-emitting device chip, a first phosphor layer 131 formed on the light-emitting device chip 110 can be configured as a phosphor-layer-emitting blue light (B). The phosphor-layer-emitting blue light (B) can have a phosphor emitted by ultraviolet rays to emit light with a wavelength in the range of 420 nm to 480 nm. A second phosphor layer 132 can be layered on top of the first phosphor layer 131 and can be configured as a phosphor-layer-emitting green light (B). The phosphor-layer-emitting green light (G) can incorporate a phosphor emitted by ultraviolet rays to emit light with a wavelength in the range of 500 nm to 550 nm. A third phosphor layer 133 can be layered on top of the second phosphor layer 132 and configured as a phosphor-layer-emitting red light (R). The phosphor-layer-emitting red light (R) can comprise a phosphor emitted by ultraviolet rays to emit light with a wavelength in the range of 580 nm to 700 nm, preferably light with a wavelength in the range of 600 nm to 650 nm. Ultraviolet rays emitted by the UV light-emitting diode chips in the preceding configuration stimulate different types of phosphors, which are contained in the first phosphor layer 131, the second phosphor layer 132, and the third phosphor layer 133. Consequently, blue light (B), green light (G), and red light (R) can be emitted by the respective phosphor layers, and light rays of the three colors can be combined to form white light (W). While Fig. 5B illustrates a light-emitting device assembly 100 in which the wavelength conversion unit has three layered phosphor layers 131-133, exemplary embodiments are not limited thereto. Referring to Fig. 5C, if the light-emitting device chip 110 is a blue-light-emitting device chip, two phosphor layers 134 and 135 can be formed on the surfaces of the light-emitting device chip 110. The two phosphor layers 134 and 135 can convert a portion of the blue light emitted by the light-emitting device chip into red and green light, respectively. The red and green light converted by the phosphor layers 134 and 135 can be combined with the unconverted blue light emitted by the light-emitting device chip 110 to form white light. In the following, a light-emitting device assembly 102, in which a light-emitting device chip 210 is applied to an assembly substrate 220, will be described with reference to Figs. 6 and 7B to 7C. Fig. 6 is a top view of a light-emitting device assembly in a vehicle headlight according to exemplary embodiments. Figures 7A to 7C are cross-sectional views of light-emitting device assemblies according to exemplary embodiments, taken along a line VII-VII' from Figure 6. With reference to Fig. 6 and Fig. 7A, the light-emitting device assembly 102 can comprise at least one light-emitting device chip 210, an assembly substrate 220 which makes it possible to mount the light-emitting device chip 210 on it, and a wavelength conversion unit 230 which contains a wavelength conversion material and is attached to a surface of the light-emitting device chip 210. The assembly substrate 220 can have a recess 224 with a reflective surface 222 formed on an inner circumferential surface inclined inwards towards the light-emitting device chip 210. The light-emitting device chip 210 can be applied to a surface of the recess 224 of the assembly substrate 220. The recess 224 can be formed by deepening the surface of the assembly substrate 220 in an area of ​​a desired (and / or alternatively predetermined) size by laser irradiation or etching, or it can be formed by casting a resin to have a desired (and / or alternatively predetermined) height along the surface edges of the assembly substrate 220, so that the reflective surface 222 protrudes. To make the reflective surface 222 more effective, a reflective layer with a high reflectivity can be provided on the reflective surface 222. The light-emitting device assembly 102 can have a plurality of wavelength conversion units 230 on the light-emitting device chips 210. The plurality of wavelength conversion units 230 can have a region extending to a region between the plurality of light-emitting device chips 210, which are arranged linearly on surfaces of the light-emitting device chips 210. The wavelength conversion units 230 serve to convert one wavelength of light emitted by the light-emitting device chip 210 into another wavelength and can be formed as a thin film on a light-emitting surface of the light-emitting device chip 210. Since the wavelength conversion unit 230 is designed as a thin film, it can have a relatively uniform shape and thickness, thereby reducing (and / or minimizing) the chromaticity deviation of light in one direction of light emission and additionally reducing the other chromaticity distributions between devices. Meanwhile, to perform the light conversion function, the wavelength conversion unit 230 can contain a wavelength conversion material such as phosphors or quantum dots. In this case, the wavelength conversion unit 230 can have a plate structure (for example, a ceramic conversion unit) formed solely from a wavelength conversion material, a layered structure in which a wavelength conversion material is dispersed in a silicon resin, or the same. The wavelength conversion unit 230 can, for example, be a phosphor layer. The wavelength conversion unit 230 can be configured such that it is longer than one side length of a light-emitting device chip 210 in the direction in which the light-emitting device chips 210 are arranged to cover an area between them. Specifically, if the light-emitting device chips 210 are arranged linearly in a horizontal direction on a bottom surface of the substrate 220, the wavelength conversion unit 230 is configured such that it is longer than one horizontal side length of a light-emitting device chip 210. Consequently, the wavelength conversion unit 230 can have a rectangular shape with a longer side in the direction in which the light-emitting device chips 210 are arranged.The longer side of the wavelength conversion unit 230 is longer than one side of the light-emitting device chip 210, and a shorter side of the unit is similar to one side of the light-emitting device chip 210. The wavelength conversion units 230 can have a rectangular shape with a longer side oriented in the same direction as the light-emitting device chips 210. If the wavelength conversion unit 230 is formed such that it has an area extending to a region between the plurality of light-emitting devices, it can convert a wavelength of light emitted in a second direction of the light-emitting device chip, thereby reducing a dark area formed between the light-emitting device chips. Consequently, a problem where emitted light is considered to be interrupted rather than continuous due to a space between chips can be solved, since wavelength conversion units are only coated on surfaces of light-emitting device chips arranged sequentially in the related light-emitting device assembly. In the case that the wavelength conversion unit 230 has a multilayer structure, the wavelength conversion unit can have three layered layers. However, exemplary embodiments are not limited to this. With reference to Fig. 7B, according to exemplary embodiments, if the light-emitting device chip 210 is a UV light-emitting device chip, the wavelength conversion unit 230 can be a first phosphor layer 231, a second phosphor layer 232 and a third phosphor layer 233 arranged sequentially according to the lengths of wavelengths such that a phosphor layer emitting light with a short wavelength is positioned on a bottom and a phosphor layer emitting light with a longer wavelength is positioned on a surface. While Fig. 7B illustrates a light-emitting device assembly 102 in which the wavelength conversion unit has three layered phosphor layers 231 to 332, exemplary embodiments are not limited thereto. Referring to Fig. 7C, if the light-emitting device chip 210 is a blue-light-emitting device chip, two phosphor layers 234 and 235 can be formed on the surfaces of the light-emitting device chip 210. The two phosphor layers 234 and 235 can convert a portion of the blue light emitted by the light-emitting device chip 210 into red and green light, respectively. The red and green light converted by the phosphor layers 234 and 235 can combine with the unconverted blue light emitted by the light-emitting device chip 210 to form white light. Likewise, although not shown, a lens unit can be formed on a surface of the assembly substrate 220 to cover the recess 224 in order to concentrate and emit light generated by the plurality of light-emitting device chips 210. The lens unit can also be made of a glass material with excellent thermal resistance properties and can be bonded to the main body via a UV-curing or heat-curing adhesive to limit (and / or prevent) the ingress of moisture into the light-emitting device chip 210, thereby ensuring a stable structure with respect to temperature and humidity. Meanwhile, the heat dissipation unit 400 can include a heat sink 410 and a cooling fan 420. The light-emitting device assembly 100 is provided on an upper area of ​​the heat dissipation unit 400, and the heat dissipation unit 400 conducts heat generated by the light-emitting device assembly 100 away from it to the outside. In detail, the heat sink 410 enables the light-emitting device assembly 100 to be mounted on its surface and allows the high-temperature heat generated by the light-emitting device assembly 100 to be dissipated to the outside. The heat sink 410 can have multiple recesses on its underside to provide a large surface area. The cooling fan 420 can be applied to the underside of the heat sink 410 to increase the heat dissipation efficiency of the heat sink 410. The reflection unit 200 is provided on a surface of the light-emitting device assembly 100 and the heat dissipation unit 400 to guide light emitted by the light-emitting device assembly 100 so that light is reflected. As illustrated in Figures 2 and 3, the reflector unit 200 has a dome-shaped cross-section to direct light emitted by the light-emitting device chip 100 towards the front of the vehicle. The reflector unit 200 is shaped with one open front face to allow the reflected light to be emitted outwards. The headlight 10 for a vehicle according to exemplary embodiments can further comprise a housing 500 that firmly supports the heat dissipation unit 400 and the reflection unit 200. In detail, the housing 500 has a housing body 510 which defines a central hole 530 that is formed such that it penetrates one surface of it to allow the heat dissipation unit 400 to be connected and installed therein, and the housing body 510 further defines a front hole 520 that is formed such that it penetrates the other surface, which is integrally connected to one surface of the housing 500 and is bent in a right-angle direction to allow the reflection unit 200 to be fixedly positioned in a surface of the light-emitting device assembly 100. Consequently, the reflection unit 200 is attached to the housing 500 in such a way that its open front corresponds to the front hole 520, in order to allow light reflected by the reflection unit 200 to pass through the front hole 520 and be emitted to the outside. The lens cover unit 300 emits light which, after being reflected by the reflection unit 200, is emitted to the outside and has a hole guide 320 and a lens 310. The guide 320 is installed in more detail on the front hole 520 of the housing 500 and directs light that passes through the front hole 520 after it has been reflected by the reflection unit 200 to a front. The guide 320, a plastic injection-molded product formed by injection molding, has a hollow cylindrical structure that accommodates the lenses 310 within it. The lenses 310 are installed in front of the guide 320 to refract and scatter light towards the front of the vehicle. The lenses 310 are preferably made of a transparent material. As mentioned above, in the light-emitting device assembly of a vehicle headlight according to exemplary embodiments, the wavelength conversion unit is formed to cover an area between a plurality of light-emitting device chips on a surface of the light-emitting device chip. Consequently, a dark area formed in the region between the continuously arranged light-emitting device chips is reduced by the wavelength conversion unit with a region extending to the area between the plurality of light-emitting device chips, thereby improving the light distribution properties of the light-emitting device assemblies. Figures 8A and 8D are diagrams showing an effect according to exemplary embodiments, and Figures 9A and 9B are photographs showing an effect according to exemplary embodiments. Figures 8A and 9A are a diagram and a photograph, respectively, each showing a light intensity when a wavelength conversion unit of the same size as a light-emitting device chip is formed. Figures 8B and 9B are a diagram and a photograph, respectively, each showing a light intensity when a wavelength conversion unit is formed on the surface of a light-emitting device chip according to exemplary embodiments. With reference to Figures 8A and 8B, when the light intensity in an upper region of the light-emitting device chip is approximately 100%, the light intensity in the region between the light-emitting device chips is approximately 50% or less. In comparison, with reference to Figure 8B, which shows a light intensity according to exemplary embodiments, when the light intensity in an upper region of the light-emitting device chip is approximately 100%, the light intensity in the region between the light-emitting device chips is approximately 70%. The light intensity in the area between the light-emitting device chips is increased by approximately 20% or more. Consequently, it can be concluded that the formation of a dark area in the region between the light-emitting device chips is reduced according to exemplary embodiments. With reference to Fig. 9A and Fig. 9B, a dark area D is visible in the area between the light-emitting device chips in Fig. 9A, while a dark area D between the light-emitting device chips in Fig. 9B is reduced. In this way, according to exemplary embodiments, the problem in which emitted light is represented as interrupted rather than continuous due to a space between chips can be solved, since wavelength conversion units are only layered on surfaces of the light-emitting device chips which are arranged sequentially in the related light-emitting device assembly. As explained above, in the case of the light-emitting device assembly and a vehicle headlight according to exemplary embodiments, a light-emitting device can be used as a light source and a continuous light can be obtained, thereby improving light distribution properties.

Claims

Light-emitting device assembly (100; 102) comprising: a substrate (120; 220); a plurality of light-emitting device chips (110; 210) arranged linearly and spatially separated from one another on the substrate (120; 220); and a plurality of wavelength conversion units (130; 230) on surfaces of the plurality of light-emitting device chips (110; 210), wherein the plurality of wavelength conversion units (130; 230) each have regions extending over regions between the plurality of light-emitting device chips (110; 210), wherein each of the plurality of wavelength conversion units (110; 210) has: a longer side extending in a first direction in which the light-emitting device chips (110; 210) are arranged;and a shorter side that is shorter than the longer side, wherein shorter sides of wavelength conversion units adjacent in the first direction of the plurality of wavelength conversion units (110; 210) are spaced apart from each other, wherein side faces of the shorter sides are exposed, wherein each of the plurality of wavelength conversion units (130; 230) has several phosphor layers (131, 132, 133; 134, 135; 231, 232, 233; 234, 235), and wherein the phosphor layers (131, 132, 133; 134, 135; 231, 232, 233; 234, 235) are stacked sequentially according to the lengths of wavelengths such that a light-emitting phosphor layer with a shorter wavelength is located at one bottom and a Light-emitting phosphor layers with a longer wavelength are arranged on a surface. Light-emitting device assembly (100; 102) according to claim 1, wherein each of the plurality of wavelength conversion units (130; 230) has a rectangular shape. Light-emitting device assembly (100; 102) according to claim 2, wherein the longer side of each of the plurality of wavelength conversion units (130; 230) is longer than a first side of each of the light-emitting device chips (110; 210), the first side being parallel to the longer side, and the shorter side of each of the plurality of wavelength conversion units (130; 230) is equal to a length of a second side of a corresponding plurality of light-emitting device chips (110; 210), the shorter side being parallel to the second side. Light-emitting device assembly (100; 102) according to any one of claims 1 to 3, wherein the substrate (220) has a recess (224), the plurality of light-emitting device chips (210) is applied to a surface of the recess (224), and the recess (224) has a reflective surface formed along an inner circumferential surface inclined inwards towards the plurality of light-emitting device chips (210). Vehicle headlight (10) comprising: the light-emitting device assembly (100; 102) according to any one of claims 1 to 4; a heat dissipation unit (400), wherein the light-emitting device assembly (100; 102) is located on the heat dissipation unit (400), the heat dissipation unit (400) being configured to conduct heat generated by the light-emitting device assembly (100; 102) outwards away from the light-emitting device assembly (100; 102); a reflection unit (200) above a top surface of the light-emitting device assembly (100; 102) and the heat dissipation unit (400), wherein the reflection unit (200) being configured to reflect light emitted by the light-emitting device assembly (100; 102) emits, conducts and reflects; and a lens cover (300) configured to emit light which is reflected outwards by the reflection unit (200). Vehicle headlight (10) according to claim 5, wherein the heat dissipation unit (400) has a heat sink (410) on a cooling fan (420), the light-emitting device assembly (100; 102) is located on the heat sink (410), the heat sink (410) is configured to dissipate heat generated by the light-emitting device assembly (100; 102) outwards and away from the light-emitting device assembly (100; 102), and the cooling fan (420) is configured to increase the heat dissipation efficiency of the heat sink (410).

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