Long light emitting diode and its application device

Abstract

The present invention discloses a long-sized light-emitting diode and an application device thereof. The long-sized light-emitting diode includes a substrate, a plurality of light-emitting diode chips arranged in a line, a plurality of electrical connection leads connected to the light-emitting diode chip electrodes, and a package encapsulant including a thin horizontal groove between two predetermined adjacent light-emitting diode chips and covering the plurality of light-emitting diode chips.

Description

[Technical field]

[0001] The present invention relates to a long-sized light-emitting diode and an apparatus for using the same, and in particular to a long-sized light-emitting diode including thin horizontal grooves in a package sealing material, thereby improving the reliability of the long-sized light-emitting diode against thermal cycles and thermal shocks. [Background technology]

[0002] Light emitting diodes (abbreviated as LED) have features such as high brightness, energy saving, multi-color, and fast change, and are already used in various lighting fields where a light source is required, such as the field of vehicle lights in automobiles. Most commercially available LEDs are packaged in a single chip, so they look like a point source when lit. Conventional LED vehicle lights feature a multi-point light source to distinguish them from incandescent bulbs.

[0003] In each of the Japanese patents (JPA 2012-59736 and JPA 2016-167518), multiple LED chips are arranged in a row and potted as a long LED strip or LED tube for indoor lighting. Multiple LED chips are arranged in a row and potted as a long LED spider light for outdoor decorative lamps. The long LED potted with multiple LED chips has low reliability against thermal cycles and thermal shocks, but the usage environment is often indoor room temperature or outdoor -30℃ to 50℃, so it is not a harsh environment with a large temperature change range and the LED will not break down in a short period of use. In contrast, the environment in which LEDs are applied to the exterior lamps of automobiles is extremely harsh. Therefore, the automotive industry has particularly strict requirements for the quality and reliability of LEDs, such as the well-known AEC-Q102 test specification and USCAR 33 test specification. In addition, the thermal shock test in USCAR 33 requires LEDs to be subjected to 1500 cycles of cold and hot shock testing, with a test temperature range of -55℃ to 150℃, which is much harsher than the use environment of the outdoor LED decorative lights mentioned above. Therefore, commercially available LEDs cannot meet the strict specification requirements for automobiles. One of the reasons for this is that the encapsulation material (colloidal material) used for encapsulation of ordinary light-emitting diodes (LEDs) is mainly epoxy resin. However, epoxy resin is a thermosetting resin that becomes solid after encapsulation and has a relatively high hardness and bulk modulus (approximately 1 to 3 Gpa). The linear thermal expansion coefficient (CLTE) of epoxy resin is about 20~40ppm / ℃ below the glass transition temperature (Tg), but when the temperature exceeds the glass transition temperature (Tg), it rises rapidly by 3~4 times, which is much larger than the linear thermal expansion coefficient of gold wire (about 14ppm / ℃).When the operating temperature of an LED exceeds the Tg temperature of its encapsulant, the difference in the linear thermal expansion coefficient between the encapsulant and the gold wire increases rapidly, causing a sudden increase in thermal stress on the gold wire inside the LED, which may cause the gold wire inside the LED to break due to thermal stress, resulting in failure of the LED and failure to pass the automotive specification test. Therefore, automotive LEDs generally use encapsulants with high Tg temperatures to improve the reliability of LED performance at high temperatures, and minimize the difference in the linear thermal expansion coefficient between the encapsulant and the gold wire.

[0004] In addition, in order to develop a linear LED vehicle light that is uniform and does not have granular luminous spots, the thin linear LED light emitting device of Patent Document TWI708908 provides a structure and manufacturing technology for the thin linear LED light emitting device, and uses an LED bar (also called an LED bar) in which a plurality of homogeneous LED chips (plurality LED chips) are packaged as a light source, and the LED bar is a linear light source that emits continuous and visually uniform light, which is particularly suitable for high-quality linear vehicle lights, unlike the conventional design in which a granular LED package is used as a light source. The thin linear LED light emitting device is applied to a linear lamp designed using a thin light guide plate, particularly a vehicle light, and can solve various problems that occur when applying a conventional LED light source to a high-quality vehicle light, such as visually discontinuous light emission, non-uniform brightness, and granular luminous spots, which often occur in conventional LED linear vehicle lights.

[0005] However, in a long-sized light-emitting diode (LED) including multiple chips, when electrodes are connected to the internal light-emitting diode chips by gold wire bonding, the difference in the coefficient of linear thermal expansion (abbreviated as CLTE) between the gold wire and the package encapsulant is large. Therefore, when the temperature changes, the thermal stress on the gold wire caused by the pressure or tension from the encapsulant changes repeatedly with the temperature drop or rise, and thermal fatigue occurs at the gold wire and the gold wire welding point. Basically, the magnitude of the thermal stress is proportional to the rigidity or bulk modulus of the encapsulant and the range of temperature change. Note that, when the length of the encapsulant of the light-emitting diode becomes longer, the thermal stress caused by the encapsulant on the gold wire and the gold wire welding point away from the center of the encapsulant in the light-emitting diode also becomes larger. In other words, since the number of chips increases and the length increases in a long-sized light-emitting diode, the deformation amount and thermal stress of the internal gold wire also become larger when the temperature changes significantly. The magnitude of this thermal stress is closely related to the material and length of the encapsulant for the light-emitting diode, which will be described in detail below.

[0006] In recent years, silica gel has been used to encapsulate light-emitting diodes to meet the specifications required for automobiles, and there are mainly two types of silica gel: methyl base silica gel and phenyl base silica gel. Methyl silica gel has a low Tg temperature (lower than -50°C) and maintains a relatively low bulk modulus in the operating environment required for automobiles (-50°C to 150°C), and is generally called soft silica gel. Take Dow-Corning's OE-6351 for example, whose bulk modulus is less than 0.01 Gpa even at -50°C to 150°C. When the temperature changes, the thermal stress of the gold wire in the light-emitting diode caused by the methyl silica gel also decreases accordingly. At -50°C to 150°C, the linear thermal expansion coefficient (CLTE) of Dow-Corning OE-6351 is about 290 ppm / °C, which is 20 times that of the gold wire. Phenyl base silica gel has a relatively high refractive index (1.5 to 1.6) and is mainly used for encapsulating high-brightness and high-efficiency light-emitting diodes.

[0007] However, the Tg temperature of phenyl (Phenyl Base) silica gel is relatively high, and most of them are between -10℃ and 50℃, as shown in the Tg of various kinds of phenyl silica gels from Dow-Corning. At room temperature, they are usually harder than methyl silica gel, and are generally called hard silica gel. The bulk modulus of these phenyl silica gels changes greatly depending on the operating environment (-50℃ to 150℃) required for automobiles. For example, Dow-Corning's OE-7662 has a bulk modulus of 1Gpa at -50℃, which is 100 times that of Dow-Corning's methyl silica gel OE-6351, but it drops rapidly near the Tg point and is below 3.0MPa at 50℃ or higher. When the temperature changes in the range of 0 to -50℃, the thermal stress caused by the phenyl silica gel on the gold wire in the light-emitting diode also becomes relatively high. The linear thermal expansion coefficient (CLTE) of phenyl silica gel also changes greatly depending on the temperature of the Tg point. Take Dow-Corning OE-7662 as an example. Its linear thermal expansion coefficient (CLTE) is about 81 ppm / ℃ at 0~-50℃, which is about one third of that of methyl silica gel OE-6351, and rises to 181 ppm / ℃ at 50~150℃, which is close to that of methyl silica gel OE-6351, but both are much larger than the 14 ppm / ℃ of gold wire.

[0008] Within the range of elastic deformation, the deformation (strain) of the material is linearly related to the stress, i.e., stress = elastic modulus (or stiffness modulus) x strain. The stiffness modulus of most resin-based materials is expressed by the bulk modulus, i.e., pressure = bulk modulus x volume deformation rate. In other words, the higher the bulk modulus of the encapsulating material, the greater the stress generated by the same amount of deformation. As for the characteristics of the encapsulating material commonly used for encapsulating the above-mentioned light-emitting diodes, the bulk modulus of epoxy resin is about 1 Gpa at -50°C to 150°C, so the thermal stress applied to the gold wire is the largest, which is the main reason why light-emitting diodes encapsulated with conventional epoxy resins do not meet the above-mentioned automotive specifications. The bulk modulus of phenyl silica gel is about 1 GPa even at -50°C to the Tg point, while the bulk modulus of methyl silica gel is relatively low in this low temperature range, only about 0.01 GPa. Therefore, when the difference in the amount of thermal deformation is small, the thermal stress caused by the phenyl silica gel on the gold wire in the light-emitting diode is much larger than that caused by the methyl silica gel.

[0009] Most materials expand and contract with heat, and the encapsulant and gold wire in LEDs are no exception. When the temperature drops, the encapsulant's linear thermal expansion coefficient is greater than that of the gold wire, so the gold wire is deformed by the pressure caused by the encapsulant's contraction. Conversely, when the temperature rises, the encapsulant's linear thermal expansion coefficient is greater than that of the gold wire, so the gold wire is pulled in the opposite direction by the encapsulant's large expansion and deforms. In other words, as the temperature goes up and down, the gold wire in the LED is repeatedly deformed by thermal stress from different directions, resulting in various thermal fatigue. If the number of such temperature cycles continues to increase, the gold wire in the LED will break due to a fatigue failure mechanism. The fatigue life of a conventional gold wire (i.e., the number of fatigue cycles until breakage) decreases as the fatigue stress increases. In other words, the greater the thermal stress of thermal fatigue, the fewer times the gold wire can withstand thermal fatigue. When testing light-emitting diodes for automotive specifications, the greater the thermal stress generated by the encapsulant, the sooner the gold wire will break under the same temperature cycle or thermal shock test.

[0010] In addition, when the temperature changes, the thermal stress acting on each gold wire in a typical long-shaped light-emitting diode varies depending on the position. The amount of thermal deformation of the encapsulant of the light-emitting diode increases linearly from the center of the encapsulant to the outer edge of the encapsulant, so the further away from the center of the encapsulant, the greater the thermal stress and deformation acting on the gold wire. Therefore, as the length of the encapsulant of the light-emitting diode increases, the thermal stress acting on the gold wire near the outer edge of the encapsulant also increases.

[0011] As an actual example, when an LED with a length of about 5 mm including four chips is encapsulated by a gold wire bonding process using an encapsulant such as Shin-Etsu's LPS-3435, KER-2460 or Dow-Corning's OE-6631, OE-6636, which is a phenyl silica gel, some of the gold wires in the LED are broken in the thermal shock test based on the above-mentioned USCAR 33 automobile specification, due to the excessive thermal stress caused by the encapsulant, and finally most of the LEDs are rejected. Further analysis shows that the failure mode of all the failed LEDs is that the gold wire closest to the edge of the package encapsulant is broken, and the gold wire breakage occurs near the first welding point, which is the soldering point near the top surface of the LED chip. This confirms that the thermal stress and deformation on the gold wire away from the center of the encapsulant is also large as mentioned above. In order to solve the above problems, the present invention innovatively designs the structure of the encapsulant for the light emitting diode, and even if a long light emitting diode including a plurality of chips is encapsulated using a high hardness encapsulant such as phenyl silica gel through a gold wire bonding process, the LED can pass the test required by the automobile specifications and be applied to the exterior vehicle light of the automobile. Summary of the Invention [Problem to be solved by the invention]

[0012] The technical problem that the present invention aims to solve is that, even when a long-sized light-emitting diode including multiple chips is encapsulated by a gold wire bonding process using an encapsulation material that is a high-hardness encapsulation material such as phenyl silica gel, the thermal stress on the gold wire in the light-emitting diode is reduced by an innovative encapsulation structure and encapsulation material structure design, and the reliability against thermal cycles and thermal shocks is improved so that the LED can pass the thermal shock test in the USCAR 33 specification for automobiles. Another feature of the present invention is that, in addition to this structure, the uniformity of linear light emission is maintained, and the special structure of the encapsulation material does not cause bright spots or dark areas, and does not cause any problems in assembly or light distribution design when assembled and used in a thin linear light-emitting device. [Means for solving the problem]

[0013] The long light emitting diode according to the present invention is applied to the thin line LED light emitting device of Patent Document TWI708908, and provides a linear light emitting diode light emitting device applied to vehicle lights of automobiles. The long light emitting diode according to the present invention includes a substrate, a plurality of electrical connection leads (e.g., gold wires, aluminum wires, or copper wires), a plurality of the same type of light emitting diode chips, and a package encapsulant. A plurality of electric conducting pads are provided on the substrate, and a plurality of light emitting diode chips are linearly arranged at an appropriate pitch, and each light emitting diode chip is fixed to the corresponding conductive pad by a die bonding process. According to the characteristics of the light emitting diode chips and the requirements for electrical connection, one end of a wire is connected to one light emitting diode chip and the other end is connected to a conductive pad beside the chip by a wire bonding process. Through an encapsulation process, a package encapsulant is placed on the substrate to cover each of the light-emitting diode chips, each of the electrical connection leads, and each of the conductive pads on the substrate, and a special feature in this case is that the package encapsulant includes a narrow horizontal groove between any two adjacent light-emitting diode chips.

[0014] In the long-sized light-emitting diode according to the present invention, the package encapsulant has at least one narrow horizontal groove, so that the equivalent encapsulant length covering the electrical connection lead in the light-emitting diode is shortened, effectively reducing the thermal stress caused by the encapsulant on the electrical connection lead (e.g., gold wire) and further reducing the risk of the electrical connection lead breaking due to thermal fatigue. In order to effectively reduce the thermal stress caused by the encapsulant on the electrical connection lead (e.g., gold wire), the depth of the groove is at least half the height of the encapsulating encapsulant. At the same time, in order to ensure that the encapsulating encapsulant effectively covers the light-emitting diode chip, the electrical connection lead, and the conductive pad of the substrate, the distance between the edge of the groove and the light-emitting diode chip, the electrical connection lead, and the conductive pad of the substrate must be at least 0.1 mm or more.

[0015] The features and technical contents of the present invention can be better understood by referring to the following detailed description of the present invention and the drawings, but the drawings provided are for reference and description purposes only and are not intended to limit the present invention. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic perspective view showing a long-sized light-emitting diode according to a first embodiment of the present invention. [Diagram 2] 1 is a schematic side view showing a long-sized light-emitting diode according to a first embodiment of the present invention. [Diagram 3] FIG. 4 is a schematic perspective view showing a long-sized light-emitting diode according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a schematic side view showing a long-sized light-emitting diode according to a second embodiment of the present invention. [Diagram 5] FIG. 13 is a schematic perspective view of a case in which a plurality of long-sized light-emitting diodes of the present invention are applied to a long-sized light-emitting diode light-emitting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the embodiments of the "long-shaped light-emitting diode and its application device" disclosed in the present invention will be described by specific specific examples, but those skilled in the art can grasp the advantages and effects of the present invention by the contents disclosed in this specification. The present invention may be implemented or applied by other different specific examples, and the details of this specification may be modified or changed in various ways based on different views and applications without departing from the spirit of the present invention. It should be noted that the drawings of the present invention are for simple explanation and are not drawn to actual size. In the following embodiments, the technical contents of the present invention will be described in more detail, but the disclosure contents are not intended to limit the scope of protection of the present invention. In this specification, various elements are represented by terms such as "first", "second", and "third", but it is understood that these elements are not limited to these terms. These terms are mainly intended to distinguish one element from the other element. In addition, the term "or" used in this specification means that any one or more combinations of the related items listed are included according to the actual situation.

[0018] 1 and 2, Fig. 1 is a perspective view showing a long-sized light-emitting diode (U) according to an embodiment of the present invention, and Fig. 2 is a side view showing the long-sized light-emitting diode (U) according to an embodiment of the present invention. In Fig. 1, the long-sized light-emitting diode (U) includes a substrate (1), twelve electrical connection leads (2), six light-emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f), and a package sealant (4). The package sealant (4) has a lateral groove (5), which is perpendicular to the arrangement direction of the six light-emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f). These six light-emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f) are all horizontal type light-emitting diode chips, and each of the light-emitting diode chips has a positive electrode (P) and a negative electrode (N) on the top surface of the chip, so that each of the light-emitting diode chips requires two independent electrical connection leads (2). The substrate (1) has six conductive pads (11, including 11a, 11b, 11c, 11d, 11e, 11f) corresponding to the six light-emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f) and one conductive pad (12) on which no light-emitting diode chip is installed. In addition, the conductive pad (12) has an area smaller than that of the conductive pad (11) since it is not necessary to install a light-emitting diode chip. The six light-emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f) are fixed to the corresponding conductive pads (11) by a die bonding process using a die bonding paste (6) so as to be arranged in a line (or straight line) at equal intervals. In a wire bonding process, one end of each electrical connection lead (2) is connected to one light-emitting diode chip and the other end is connected to the adjacent conductive pad (11) or conductive pad (12). In this embodiment, a gold wire with a wire diameter of 1.2 mil is used as the electrical connection lead (2). In an encapsulation process, a package sealant (4) is provided on the upper surface of the substrate 1 so as to cover each of the light-emitting diode chips, each of the electrical connection leads (2), and each of the conductive pads (11, 12) on the substrate (1).As shown in Fig. 2, the package sealant (4) in this embodiment covers only the upper surface of the substrate (1), and the height (T) of the sealant is about 1.7 mm. One of the features of the present invention is that the package sealant (4) includes a lateral groove (5) between two predetermined adjacent light-emitting diode chips. In this embodiment, the lateral groove (5) in the package sealant (4) is provided between the third light-emitting diode chip (3c) and the fourth light-emitting diode chip (3d), and the direction of the lateral groove (5) is perpendicular to the arrangement direction of the six light-emitting diode chips.

[0019] In this embodiment, the transverse groove (5) is formed in the encapsulation preform (not shown) of the light emitting diode by cutting the encapsulation preform with a diamond cutter. Therefore, in FIG. 2, the width (W) of the transverse groove (5) is determined by the thickness of the diamond cutter used. Basically, the width (W) of the transverse groove (5) should not be too large to avoid affecting the shape of the light of the light emitting diode or causing visual variations. Therefore, due to the limitation of the thickness of the diamond cutter, the width (W) of the transverse groove (5) of the present invention is preferably 0.1-0.3 mm. In FIG. 2, the depth of the transverse groove (5) is determined by the height (H) of the bottom of the transverse groove. The bottom height (H) of the horizontal groove is required to be at least half (1.7 mm) of the height (T) of the package encapsulant in order to effectively reduce the thermal stress of the encapsulant on the electrical connection leads (e.g., gold wires), so that the bottom height (H) of the groove is 0.1 mm to half (i.e., 0.8 mm) of the height of the package encapsulant, ensuring that the package encapsulant effectively covers the conductive pads of the substrate. The bottom height (H) of the groove in this embodiment is controlled to 0.1 mm to the height of the upper surface of the light-emitting diode chip (3c, 3d), so that the thermal stress of the encapsulant on the electrical connection leads (e.g., gold wires) is more effectively reduced. Since the height of the light-emitting diode chips (3c, 3d) in this embodiment is 0.3 mm, in a preferred embodiment of the present invention, the height (H) of the bottom of the horizontal groove is controlled to 0.1 mm to 0.3 mm so that the encapsulant completely covers each of the light-emitting diode chips and each of the conductive pads on the substrate and can effectively reduce the thermal stress caused by the encapsulant in the electrical connection leads.

[0020] How to select two adjacent LED chips to install the lateral grooves (5) or how many lateral grooves (5) to install are related to the total length of the package encapsulant, the tensile strength of the package encapsulant and the electrical connection leads (2) and the temperature range of thermal cycles (or thermal shocks). In short, the more lateral grooves there are in the LED encapsulant, the smaller the thermal stress on the electrical connection leads in the LED, and the higher the reliability against thermal cycles and thermal shocks. Relatively, the more lateral grooves there are in the LED encapsulant, the higher the manufacturing difficulty and cost.

[0021] The effect of the present invention will be described. The long-sized light-emitting diode in this embodiment is configured such that the package encapsulant has a horizontal groove whose depth is close to the surface of the light-emitting diode, and the effect is to divide the original encapsulant into two package encapsulants with half the length, that is, to form the centers of two independent new encapsulants. This corresponds to halving the distance from the center of the encapsulant coated on the right side of the gold wire at the rightmost edge of the light-emitting diode. When the effective length of the thermal stress caused by the coated encapsulant applied to the gold wire is shortened, the thermal stress caused by the encapsulant on the gold wire is relatively reduced, so that the risk of the gold wire breaking due to thermal fatigue is reduced, and the life and reliability of the light-emitting diode to withstand cold-heat cycles and cold-heat presses are improved. As described above, the present invention is not limited to the material and form of the substrate (1). For example, the substrate (1) is a two-layer substrate with conductive layers on both the upper and lower layers (front and back), but it may also be a BT (Bismaleimide Triazine) plate, a ceramic substrate, or a composite substrate in which separated metal blocks are embedded in resin. Alternatively, the substrate (1) may be a BT plate or a ceramic substrate including two or more conductive layers to improve the flexibility of the circuit wiring design. Note that the present invention is not limited to the shape of the conductive pads (11) and (12).

[0022] The present invention is applicable to light emitting diode chips in different embodiments, including vertical light emitting diode chips (positive pole (P) and negative pole (N) of the LED chip are separated on different surfaces of the LED chip, i.e., the top and bottom surfaces), horizontal light emitting diode chips (positive pole (P) and negative pole (N) of the LED chip are both on the top or upper surface of the LED chip), etc. Among them, both the vertical light emitting diode chips and the horizontal light emitting diode chips need to be encapsulated by die bonding and wire bonding processes, which causes the problem that the gold wires mentioned above will be broken due to thermal fatigue.

[0023] 3 and 4 show a second embodiment of the present invention, in which the light-emitting diode chip shown is a vertical light-emitting diode chip. In the vertical light-emitting diode chip, one electrode (e.g., positive electrode (P)) is on the upper surface of the chip, and the other electrode (e.g., negative electrode (N)) is on the lower surface of the chip. In this embodiment, the light-emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f) are first fixed to the corresponding conductive pads (11, including 11a, 11b, 11c, 11d, 11e, 11f) by a conductive die bonding paste (6) (e.g., silver paste), and then connected to the electrodes (P) on the upper surface of each light-emitting diode chip and the adjacent other conductive pads (11) or conductive pads (12) by a wire bonding process via the electrical connection leads (2). In this embodiment, the light-emitting diode chip (3a) is connected to the corresponding conductive pad (11a), and the electrical connection lead (2) connected to the electrode (P) on the surface of the light-emitting diode chip (3a) is bonded to the conductive pad (11b). In this manner, only the electrical connection lead (2) connected to the electrode (P) on the surface of the light-emitting diode chip (3f) is bonded to the conductive pad (12).

[0024] In this embodiment, the package encapsulant (4) includes two horizontal grooves (51, 52), in which the first horizontal groove (51) is provided between the second light emitting diode chip (3b) and the third light emitting diode chip (3c), and the second horizontal groove (52) is provided between the fourth light emitting diode chip (3d) and the fifth light emitting diode chip (3e), and the direction of these horizontal grooves (51, 52) is perpendicular to the arrangement direction of these six light emitting diode chips (3a, 3b, 3c, 3d, 3e, 3f). As described above, since the number of horizontal grooves in the encapsulant for the light emitting diode in this embodiment is increased, the reliability against thermal cycles and thermal shocks is also increased.

[0025] The long-sized light-emitting diode of the present invention has at least one narrow horizontal groove in the package encapsulant, which shortens the effective length of the thermal stress caused by the encapsulant on the electrical connection lead, effectively reducing the thermal stress caused by the encapsulant on the wire, and further reducing the risk of the wire breaking due to thermal fatigue.

[0026] It should also be noted that although the present invention does not restrict the direction of wire bonding on the electrical connection leads in the light-emitting diode, the wire bonding direction of the electrical connection leads on both sides of each encapsulant lateral groove should be as parallel to the lateral groove direction as possible to avoid affecting the formation of the encapsulant lateral groove or the encapsulant being unable to cover all of the electrical connection leads.

[0027] It should be noted that the present invention does not limit the number of light-emitting diode chips. The present invention also does not limit the number of lateral grooves in the encapsulant of the light-emitting diode. When forming the lateral grooves in the encapsulant of the light-emitting diode of the present invention, it is not limited to forming them by cutting the encapsulation preform with a diamond cutter, and for example, the encapsulant may be covered by a molding process such as direct molding, transfer molding, or injection molding, and the lateral grooves may be formed in the encapsulant at the same time. However, when forming the lateral grooves in the encapsulant by the molding process, the lateral grooves in the encapsulant need to have a draft angle depending on the demolding conditions, and the width of the lateral grooves needs to be relatively wide, that is, it is desirable that the light-emitting diode chips are installed at a large pitch and the number of lateral grooves that can be installed in the encapsulant is relatively small.

[0028] In one practical sample function test of the present invention, the resin used to encapsulate the light emitting diode is Dow Corning's phenyl silica gel. Two different types of light emitting diodes, which have the same length and the same light emitting diode chips installed inside, but one encapsulant has a horizontal groove and the other encapsulant does not have a horizontal groove, are subjected to a thermal shock test in USCAR 33 for automotive LED. The test conditions are thermal shock at a low temperature of -55°C to a high temperature of 150°C, and the test time is 1512 hours (equivalent to 3000 cycles). As a result of the test, after 1344 hours of testing, the defective rate of the light emitting diode sample without the horizontal groove in the encapsulant is 80 / 80, that is, all 80 test samples are defective. However, after 1512 hours of testing, the defective rate of the light emitting diode sample with the horizontal groove in the encapsulant is 0 / 80, that is, there are no defective products. As a result of the test, the specific validity and inventive step of the present invention are fully confirmed.

[0029] 5 is a perspective schematic diagram of a case where the long-sized light-emitting diode of the present invention is applied to a long-sized light-emitting diode light-emitting device (Z). In this embodiment, the long-sized light-emitting diode light-emitting device (Z) includes a printed circuit board (P), a plurality of the long-sized light-emitting diodes (U) of the present invention, and at least one electrical connector (C). The long-sized light-emitting diodes (U) and the electrical connector (C) are mounted on the printed circuit board (P) by an SMT process to form the long-sized light-emitting diode light-emitting device (Z). The present invention does not limit the number of the long-sized light-emitting diodes (U).

[0030] The above disclosure is merely a preferred embodiment of the present invention, and does not limit the scope of the claims of the present invention. Therefore, any equivalent technical modifications according to the contents of the specification and drawings of the present invention are included in the scope of the claims of the present invention. [Explanation of symbols]

[0031] Z: Long LED light emitting device U: Long LED W: Width of lateral groove H: Height of bottom of horizontal groove P: Printed circuit board C: Electrical connector 1: Substrate 11, 11a, 11b, 11c, 11d, 11e, 11f: Conductive pads 12: Conductive pad 2: Electrical connection leads 3a, 3b, 3c, 3d, 3e, 3f: light-emitting diode chips 4: Packaging encapsulation materials 5: Yokomizo 51: The First Yokomizo 52: The second Yokomizo 501: Bottom of the horizontal groove 6: Die bonding paste

Claims

1. a substrate including a plurality of conductive pads; a plurality of light emitting diode chips each mounted on a corresponding one of the conductive pads of the substrate so as to be linearly arranged; a plurality of electrical connection leads, each of which has one end connected to one of the light emitting diode chips and the other end connected to an adjacent one of the conductive pads; a package encapsulant that is provided on the substrate so as to cover each of the light emitting diode chips, each of the electrical connection leads, and each of the conductive pads on the substrate, and that includes a lateral groove between two adjacent light emitting diode chips, the direction of the lateral groove being substantially perpendicular to the arrangement direction of the plurality of light emitting diode chips, and the height of a bottom of the lateral groove being 0.1 mm to half the height of the package encapsulant; A long light emitting diode comprising:

2. 2. The long-sized light-emitting diode according to claim 1, wherein the lateral groove is formed by cutting the package sealant after the light-emitting diode chip has undergone an encapsulation process, and the width of the lateral groove is 0.1 mm to 0.3 mm.

3. 2. The long light-emitting diode according to claim 1, wherein the height of the bottom of the lateral groove is 0.1 mm to 0.3 mm.

4. 2. The long light-emitting diode according to claim 1, wherein the lateral groove is formed by molding in a process of encapsulating the light-emitting diode chip.

5. a substrate including a plurality of conductive pads; Six vertical light emitting diode chips are provided on the corresponding conductive pads so as to be arranged in a line at equal intervals; six electrical connection leads, each having one end connected to one of the light emitting diode chips and the other end connected to an adjacent one of the conductive pads; a package encapsulant provided on the substrate so as to cover each of the light emitting diode chips, each of the electrical connection leads, and each of the conductive pads on the substrate; Equipped with the package encapsulant includes a first horizontal groove between the second light-emitting diode chip and the third light-emitting diode chip, the direction of the first horizontal groove being perpendicular to the arrangement direction of the six light-emitting diode chips, and the package encapsulant includes a second horizontal groove between the fourth light-emitting diode chip and the fifth light-emitting diode chip, the direction of the second horizontal groove being perpendicular to the arrangement direction of the six light-emitting diode chips, and the height of the bottoms of the first horizontal groove and the second horizontal groove is 0.1 mm to half the height of the package encapsulant.

6. 1. An elongated light emitting diode light emitting device having a printed circuit board including at least one electrical connector and a plurality of elongated light emitting diodes, Each of the elongated light emitting diodes is a substrate including a plurality of conductive pads; a plurality of light emitting diode chips each disposed on a corresponding one of the conductive pads so as to be linearly arranged; a plurality of electrical connection leads, one end of which is connected to one of the light emitting diode chips and the other end of which is connected to an adjacent one of the conductive pads; a package encapsulant provided on the substrate so as to cover each of the light emitting diode chips, each of the electrical connection leads, and each of the conductive pads on the substrate; Equipped with the package encapsulant includes a horizontal groove between two adjacent light-emitting diode chips, the direction of the horizontal groove is approximately perpendicular to the arrangement direction of the plurality of light-emitting diode chips, and the height of the bottom of the horizontal groove is 0.1 mm to half the height of the package encapsulant.

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