Element mounted substrate, vehicle lighting fixture, and element mounting method

Abstract

To provide an element mounted substrate capable of suppressing misalignment of light emitting elements, a vehicle lighting fixture, and an element mounting method.SOLUTION: It is characterized in that an element mounted substrate (20) for mounting a light-emitting element (10) having an electrode (10a) with a shape corresponding to a land (20a) provided on a surface (23), has a configuration in which the land (20a) includes a plurality of divided lands (20b), and / or the electrode (10a) includes a plurality of divided electrodes (10b).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device mounting board, a vehicle lamp, and a device mounting method. [Background technology]

[0002] An example of a conventional vehicle lamp is shown in Fig. 8(a). As shown in Fig. 8(a), the vehicle lamp 50 includes a reflector 51, a lens 52, and a heat sink 53. As an example, an element mounting substrate 20 having a light emitting element 10 mounted thereon is disposed on the heat sink 53. The light emitting element 10 emits light when supplied with power from a wiring pattern (not shown) provided on the element mounting substrate 20, and emits emitted light L. The emitted light L is reflected by the reflector 51 in a desired direction and radiated to the outside via the lens 52.

[0003] FIG. 8(b) shows a cross-sectional view of the device mounting substrate 20. A light-emitting element 10 is mounted on a surface 23 of the device mounting substrate 20. The light-emitting element 10 has two electrodes (not shown), corresponding to, for example, an anode and a cathode. Meanwhile, a wiring pattern (not shown) is formed on the surface 23 of the device mounting substrate 20, and part of this wiring pattern forms a land corresponding to the electrode of the light-emitting element 10. Generally, the land of the device mounting substrate 20 has the same shape as the electrode of the light-emitting element 10, and the light-emitting element 10 is fixed to the device mounting substrate 20 by interposing solder (not shown) or the like between the land and the electrode. FIG. 8(c) shows an example of a land pattern P of the device mounting substrate 20. The electrode pattern of the light-emitting element 10 is also the same pattern as pattern P.

[0004] As a conventional technology for the above-described vehicle lamp and element mounting board, for example, a vehicle lamp and element mounting board disclosed in Patent Document 1 are known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-73762 Summary of the Invention [Problem to be solved by the invention]

[0006] 8(a), deviation in the mounting position of the light-emitting element 10 (mainly deviation in position within the surface 23 of the element mounting substrate 20) can significantly affect the light distribution characteristics of the vehicle lamp 50. If the mounting position of the light-emitting element 10 deviates from the design value, the incident position of the emitted light L on the reflector 51 deviates, and as a result, the reflected emitted light L enters the lens 52 at an angle different from the design value. This causes the light distribution characteristics to deviate from the design value.

[0007] As vehicle lamps 50, or light-emitting element units in general, become smaller and cheaper, the difficulty of light distribution design is becoming significantly higher. That is, in order to achieve miniaturization at low cost, it is necessary to effectively utilize the limited light output of the light-emitting element 10 and efficiently control the light distribution. In other words, to obtain light distribution performance with a predetermined margin, it is necessary to minimize the deviation in the mounting position of the light-emitting element 10. Furthermore, minimizing the deviation in the mounting position of the light-emitting element 10 also contributes to relaxing the manufacturing tolerances of other components (reflector 51, lens 52, etc.).

[0008] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide an element mounting board, a vehicle lamp, and an element mounting method that are capable of suppressing misalignment of the mounting position of a light-emitting element. [Means for solving the problem]

[0009] In order to solve the above problem, the element mounting board of the present invention is an element mounting board for mounting a light-emitting element on a land provided on the surface, the light-emitting element having an electrode having a shape corresponding to the land, and is characterized in that the land is configured to include a plurality of divided lands and / or the electrode is configured to include a plurality of divided electrodes.

[0010] In the device mounting board of the present invention, the land has a shape corresponding to the electrode of the light-emitting element, and the land further includes a plurality of divided lands and / or the electrode includes a plurality of divided electrodes, so that when the light-emitting element is mounted on the device mounting board, it is possible to prevent the light-emitting element from being misaligned.

[0011] In one aspect of the present invention, each of the divided lands and / or the divided electrodes is a rectangle with at least one side having a length of 0.2 mm or less.

[0012] In addition, one aspect of the present invention is characterized in that the land includes a plurality of split lands and the electrode includes a plurality of split electrodes, the split lands have approximately the same shape as the split electrodes, and the multiple split lands within the land are arranged to correspond to the arrangement of the multiple split electrodes within the electrode.

[0013] In one aspect of the present invention, a plurality of the lands are provided corresponding to a plurality of electrodes of the light-emitting element.

[0014] In addition, in one aspect of the present invention, the size of the divided land provided below the light-emitting area of ​​the light-emitting element is larger than the size of the divided land provided below the area other than the light-emitting area.

[0015] In one aspect of the present invention, the divided lands are arranged in a matrix within the land, and the pitch between adjacent divided lands within the land is smaller than the pitch between adjacent lands.

[0016] In one aspect of the present invention, the pitch between adjacent divided lands within the land is approximately 1 / 3 of the length of the opposing sides of the adjacent divided lands.

[0017] In addition, one aspect of the present invention is characterized in that it further comprises a connecting portion formed by at least one of the inner layer and the back surface layer, and a plurality of connecting portions connecting each of the divided lands arranged on the surface layer to the connecting portion.

[0018] In one aspect of the present invention, the connection portion is at least one of a via and a filled cap.

[0019] In addition, one aspect of the present invention is characterized in that it further comprises at least one of a land bridging portion that connects adjacent split lands of the plurality of split lands with a wiring pattern having a width narrower than the width of the split lands, and an electrode bridging portion that connects adjacent split electrodes of the plurality of split electrodes with a wiring pattern having a width narrower than the width of the split electrodes.

[0020] In addition, in one aspect of the present invention, the land bridging portion connects the approximately central portions of the opposing sides of adjacent divided lands, and the electrode bridging portion connects the approximately central portions of the opposing sides of adjacent divided electrodes.

[0021] In addition, one aspect of the present invention is characterized in that the light-emitting element includes a plurality of lands corresponding to a plurality of the electrodes included therein, the land bridging portion connects positions shifted in the gap direction between the lands from the centers of the opposing sides of adjacent divided lands, and the electrode bridging portion connects positions shifted in the gap direction between the electrodes from the centers of the opposing sides of adjacent divided electrodes.

[0022] In addition, in one aspect of the present invention, the width of the land bridging portion is less than 1 / 2, preferably approximately 1 / 3, of the length of the opposing sides of the adjacent divided lands, and the width of the electrode bridging portion is less than 1 / 2, preferably approximately 1 / 3, of the length of the opposing sides of the adjacent divided electrodes.

[0023] In order to solve the above problems, a vehicle lamp according to the present invention is characterized by including the above element mounting board and a light emitting element mounted on the element mounting board.

[0024] In order to solve the above problem, the element mounting method of the present invention is an element mounting method for mounting a light-emitting element on a land provided on a surface, the light-emitting element having an electrode having a shape corresponding to the land, and is characterized in that the land is configured to include a plurality of divided lands and / or the electrode is configured to include a plurality of divided electrodes. [Effects of the Invention]

[0025] The present invention can provide an element mounting board, a vehicle lamp, and an element mounting method that can suppress displacement of the mounting position of a light-emitting element. [Brief explanation of the drawings]

[0026] [Figure 1] 1A is a longitudinal cross-sectional view showing an example of the configuration of an element mounting substrate on which a light-emitting element is mounted, FIG. 1B is a plan view showing an example of an electrode of the light-emitting element, and FIG. 1C is a plan view showing an example of a land and a wiring pattern of the element mounting substrate, according to an embodiment. [Figure 2] 1A to 1C are cross-sectional views illustrating the principle of the effect of the device mounting board according to the embodiment. [Figure 3] 1(a) to 1(c) are plan views showing an example of the pattern of the electrodes of the light-emitting element and the lands of the element mounting substrate according to the first embodiment. [Figure 4] In the second embodiment, (a) to (c) are plan views showing the connection positions of the connecting portions of the lands, (d) is a cross-sectional view showing the connecting portion when a via is used, and (e) is a cross-sectional view showing the connecting portion when a filled cap is used. [Figure 5] In the third embodiment, (a) is a cross-sectional view of a light-emitting element, (b) and (c) are plan views showing an example of the arrangement of split electrodes, and (d) is a plan view showing the direction in which a crack progresses in a land or electrode. [Figure 6] FIG. 10 is a plan view showing a land bridging portion and an electrode bridging portion according to a third embodiment. [Figure 7]FIG. 11 is a plan view showing a land bridging portion and an electrode bridging portion according to a modified example of the third embodiment. [Figure 8] 1A is a cross-sectional view showing an example of a vehicle lamp according to the prior art, FIG. 1B is a cross-sectional view showing an example of an element mounting board on which a light-emitting element is mounted, and FIG. 1C is a plan view showing an example of a land of the element mounting board. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be assigned the same reference numerals, and redundant explanations will be omitted where appropriate. In the following explanation, an embodiment in which an element mounting board according to the present invention is applied to a vehicle lamp mounted on a vehicle will be described as an example. The configuration of the vehicle lamp is similar to the conventional vehicle lamp 50 shown in FIG. 8(a), so a detailed explanation will be omitted. However, the vehicle lamp according to this embodiment is not limited to the configuration shown in FIG. 8(a), and can be applied to other configurations, such as a configuration in which emitted light L is guided by a light guide, or a configuration in which emitted light L is directly collected by a lens, etc.

[0028] (First embodiment) A device mounting board, a vehicle lamp, and a device mounting method according to this embodiment will be described with reference to FIGS. 1 to 3. FIG. 1(a) is a longitudinal cross-sectional view showing an example of the configuration of a device mounting board 20 according to this embodiment. As shown in FIG. 1(a), the device mounting board 20 has a divided land 20b formed on a front surface 23. As described below, the divided land 20b is part of a wiring pattern formed on the front surface 23. As shown in FIG. 1(a), the light-emitting element 10 has a divided electrode 10b. Depending on how light is extracted from the light-emitting element 10, the divided electrode 10b may be formed on the front or back surface of the light-emitting element 10. In this embodiment, the divided electrode 10b is formed on the back surface. That is, the light-emitting element 10 of this embodiment emits emitted light L from the front surface. As shown in FIG. 1(a), the light-emitting element 10 is fixed by connecting the divided electrode 10b to the divided land 20b via solder 22 or the like. As described below, the divided electrode 10b is one of the divided portions of the electrode 10a, and the divided land 20b is one of the divided portions of the land 20a.

[0029] Here, the material of the device mounting substrate 10 is not particularly limited and may be a resin substrate, a metal substrate, or the like. In this embodiment, an LED (Light Emitting Diode) is described as an example of the light emitting element 10, but other types of light emitting elements such as an LD (Laser Diode) may also be used. Another example of the specific configuration of the light emitting element 10 according to this embodiment will be described later in the description of FIG. 5(a).

[0030] FIG. 1(b) shows an example of an electrode 10a formed on the back surface of the light-emitting element 10. In this embodiment, the light-emitting element 10 has two electrodes, an anode and a cathode. However, the present invention is not limited to this, and the light-emitting element 10 may have one electrode or three or more electrodes. In particular, when there is one electrode on the back surface, the other electrode is provided on the front surface. The light-emitting element 10 is fixed to the element mounting substrate 20 by, for example, solder reflow. As shown in FIG. 1(b), each electrode 10a includes two split electrodes 10b. In other words, each electrode of the light-emitting element 10 is split into two. As will be described later, the number of split electrodes is not limited to two, and may be any number appropriate depending on the positioning accuracy, etc.

[0031] FIG. 1(c) shows an example of lands 20a formed on the surface 23 of the device mounting substrate 20. According to this embodiment, two lands 20a are provided corresponding to the two electrodes 10a. Furthermore, as shown in FIG. 1(c), each land 20a includes two split lands 20b corresponding to the two split electrodes 10b. Here, the lands 20a and the electrodes 10a have roughly the same outer shape, and the split lands 20b and the split electrodes 10b also have roughly the same outer shape. The device mounting substrate 20 according to this embodiment includes multiple split lands 20b to more accurately position the light-emitting element 10 for mounting. Note that FIG. 1(c) also shows a wiring pattern 21 other than the lands 20a. A portion of the wiring pattern 21 is connected to the lands 20a, and power is supplied to the light-emitting element 10 from the connected wiring pattern 21 via the lands 20a and the electrodes 10a.

[0032] Next, the principle of the effect of the multiple divided lands 20b in the device mounting board 20 according to this embodiment will be described with reference to FIG. 2. When the electrodes of a light-emitting element (generally a semiconductor element) are soldered to the lands of the device mounting board, a self-alignment effect due to the solder often occurs. This self-alignment effect is a phenomenon caused by the surface tension of the solder. The self-alignment effect corrects the misalignment between the land of the device mounting board and the electrode of the light-emitting element due to the molten solder, and the land and electrode of the light-emitting element are brought into the designed position.

[0033] FIG. 2(a) shows the relative positions of the lands 20a and electrodes 10a of the light-emitting element 10 immediately after reflow, according to a conventional technique in which the lands 20a of the device mounting substrate 20 and the electrodes 10a are not separated. As shown in FIG. 2(a), the molten solder 22 causes misalignment between the lands 20a and the electrodes 10a. At this time, a surface tension Fs is generated on the surface of the solder 22 for each land 20a. This surface tension Fs can be decomposed into a horizontal component Fh and a vertical component Fv. The horizontal component Fh acts as a force that moves the electrodes 10a toward the lands 20a, and the horizontal component Fh generates a self-alignment effect. Meanwhile, the vertical component Fv holds the light-emitting element 10 and attracts it to the lands 20a. In other words, when the solder melts and the surface tension of the solder acts, the light-emitting element 10 is attracted to the lands 20a of the device mounting substrate 20 (the light-emitting element 10 sinks) and is drawn toward the lands 20a. 2(b), the shape of the molten solder 22 changes, and when the horizontal component Fh is balanced on the left and right, the light emitting element 10 stops. This is the self-alignment effect.

[0034] FIG. 2(c) shows the positional relationship between the split lands 20b and the split electrodes 10b immediately after reflow in this embodiment, where the land 20a of the device mounting substrate 20 includes split lands 20b and the electrode 10a of the light emitting element 10 includes split electrodes 10b. In this case, four surface tensions Fs are generated for each combination of corresponding split lands 20b and split electrodes 10b, and each of these surface tensions generates a horizontal component Fh and a vertical component Fv. The four horizontal components Fh expand the area contributed by the surface tension, increasing the force for correcting misalignment. Furthermore, because the four horizontal components Fh independently correct the misalignment between the split lands 20b and the split electrodes 10b, the average position approaches the designed position.

[0035] Variations in the arrangement of split lands 20b within land 20a and split electrodes 10b within electrode 10a will be described with reference to Figure 3. In Figure 3, two electrodes 10a, an anode and a cathode, are assumed, and the upper row shows the patterns of electrode 10a and split electrodes 10b, while the lower row shows the patterns of lands 20a and split lands 20b corresponding to electrode 10a and split electrodes 10b.

[0036] The conventional pattern shown in Figure 3 shows electrodes 10a and lands 20a according to the prior art that do not include split electrodes 10b and split lands 20b. One of the electrodes 10a is an anode electrode, and the other is a cathode electrode. As shown in the conventional pattern of Figure 3, two lands 20a are provided on the device mounting substrate 20 corresponding to the two electrodes 10a. The electrodes 10a and lands 20b have approximately the same shape, with the length of the short side of the land 20a being A and the length of the long side being B.

[0037] The example patterns shown in Figure 3 show three patterns of division methods, (a), (b), and (c). Figure 3(a) shows an example in which each electrode 10a is divided into three, i.e., each electrode 10a includes three divided electrodes 10b. Each land 20a includes three divided lands 20b corresponding to the divided electrodes 10b. In other words, the divided lands 20b are arranged in a 1 x 3 matrix within the land 20a. As shown in Figure 3(a), each divided land 20b has a horizontal length of C and a vertical length of D. The pitch between adjacent lands 20a is length E, and the pitch between adjacent divided lands 20b within the land 20a is length F. In this case, for each length, (2C+2D)×(number of divisions)>2A+2B That is, in the pattern of Figure 3(a), the perimeter of the land is longer than in the conventional pattern, which increases the effect of the surface tension described above.

[0038] Here, the size of the divided land 20b will be considered. The size of the divided land 20b can be set, for example, based on the allowable positioning accuracy. As an example, the target value of the positioning accuracy is 50 μm, which is known in CSP (Chip Size Package) and the like. On the other hand, if the ratio of the positioning accuracy to the length of one side of the divided land 20b is assumed to be 1 / 3, for example, the target value of the length of one side of the divided land 20b is 50 μm × 3 = approximately 150 μm. With a margin of ±50 μm on this 150 μm, the target value of the divided land 20b can be set, for example, to 0.1 mm to 0.2 mm. That is, as an example, 0.1mm≦C, D≦0.2mm Of course, the target size of the divided lands 20b can vary depending on the allowable positioning accuracy and the like.

[0039] Furthermore, with regard to the land pitch E and the divided land pitch F, from the viewpoint of avoiding solder bridges between the lands 20a, E>F It is preferable to set it as follows. Also, assuming that the pitch F between the divided lands is approximately the same as the positioning accuracy, for the same reason as above, the pitch F between the divided lands can be set to approximately 1 / 3 of the horizontal length C of the divided land 20b.

[0040] The example pattern in FIG. 3(b) is an example in which one more row of divided lands 20b within the land 20a is added to that in FIG. 3(a), resulting in a 2 x 5 matrix pattern. In other words, the divided land 20b is divided vertically and horizontally. If the size of the electrode 10a of the light-emitting element 10 increases, the number of divisions can be increased as appropriate. In this case, the above-mentioned relationships hold for the lengths A to F.

[0041] FIG. 3(c) shows a pattern in which the size of the divided lands 20b is changed according to the light-emitting region of the light-emitting element 10. Depending on the light-emitting element 10, the light-emitting region on the surface may be biased. For example, in the example of FIG. 3(c), the light-emitting region 11 is biased toward the upper part of the light-emitting element 10. In such a case, it is preferable to make the size of the divided lands 20b arranged below the light-emitting region relatively larger than the size of the divided lands 20b arranged below the other parts of the light-emitting region. This is to make the supply of power to the light-emitting element 10 more efficient. As such, the size of the divided lands 20b within the land 20a does not need to be the same and may be changed as appropriate depending on the design conditions, etc. In this case, the above-mentioned relationship holds for the lengths A to F.

[0042] As described above in detail, the element mounting board, vehicle lamp, and element mounting method according to this embodiment make it possible to provide an element mounting board, vehicle lamp, and element mounting method that can suppress misalignment of the mounting position of the light-emitting element.

[0043] (Second embodiment) The element mounting board, vehicle lamp, and element mounting method according to this embodiment will be described with reference to Figure 4. In this embodiment, the divided lands 20b in the above-described embodiment are connected using an inner layer or a back surface layer of the element mounting board 20. Therefore, the vehicle lamp and element mounting method are the same as those in the above-described embodiment, and therefore will not be illustrated, and Figures 1 to 3 will be referred to if necessary.

[0044] In this embodiment, each of the divided lands 20b is connected to the inner or rear surface of the device mounting board by a via or a filled cap, forming a connection portion through the inner or rear surface. Figures 4(a) to 4(c) show the lands (20a, 20b) in Figure 3 again, showing the connection position Cp, which is the location of the via or filled cap. A filled cap is a structure in which a through-hole portion is provided in the device mounting board 20, the inner wall of the through-hole is plated, and the through-hole is filled with resin. The upper and lower ends of the through-hole, where the resin is exposed, are plated. In other words, both ends of the through-hole are capped with plating. For example, the filled cap is provided directly below the light-emitting element 10, and is configured to dissipate heat generated by the light-emitting element 10 via as short a path as possible. The via or filled cap is an example of a "connection portion" according to the present invention.

[0045] Fig. 4(d) shows a configuration in which a connecting portion is formed using a via. Fig. 4(d) shows the case of the divided land 20b shown in Fig. 4(b), but the case of the divided lands 20b shown in Figs. 4(a) and (c) can be considered similarly. As shown in Fig. 4(d), each divided land 20b is connected to the first inner layer of the device mounting substrate 20-1 by a via 24, and the first inner layer forms the connecting portion 25. In this embodiment, a configuration in which the connecting portion 25 is formed by the first inner layer will be described as an example, but this is not limiting, and a connecting layer may also be formed in the second inner layer 26 or the back surface layer 27.

[0046] Here, we explain the reason for providing the connecting portions 25 on the split lands 20b in this embodiment. In this embodiment, by dividing the land 20a into split lands 20b, misalignment of the mounting position of the light-emitting element 10 is suppressed. In this case, each split land 20b is inevitably isolated, which may result in, for example, variations in the potential between the split lands 20b. While connecting the split lands 20b to each other would ensure the same potential, this is not possible on the surface layer where the split lands 20b are located without some ingenuity. Therefore, in this embodiment, connecting portions are formed using the inner layer or back surface layer of the element mounting substrate 20, and these connecting portions connect the split lands 20b to each other. If the split lands 20b were left as they are, current bias may occur, resulting in variations in heat generation among the split lands 20b. In this embodiment, the connecting portions 25 equalize the potential between the split lands 20b to reduce variations in heat generation, thereby effectively suppressing damage to the light-emitting element 10 due to localized heat generation.

[0047] Figure 4(e) shows a form in which a connecting portion is formed using a filled cap. Figure 4(e) shows the case of the divided lands 20b shown in Figure 4(b), but the cases of the divided lands 20b shown in Figures 4(a) and (c) can be considered similarly. As shown in Figure 4(e), each divided land 20b is connected to the back surface layer of the element mounting substrate 20-2 by a filled cap 28, and the back surface layer forms a connecting portion 29. In this embodiment, the divided lands 20b and the connecting portion 29 form the cap of the filled cap 28. Furthermore, a resin 30 is filled in the sealed space formed by the cap and the inner wall.

[0048] As described above, the element mounting board, the vehicle lamp, and the element mounting method according to this embodiment also make it possible to provide an element mounting board, a vehicle lamp, and an element mounting method that can suppress misalignment of the mounting position of the light-emitting element. This embodiment is particularly effective in suppressing damage to the light-emitting element 10 caused by variations in heat generation in the divided lands 20b. Note that, although this embodiment has been described by way of example with reference to a form in which a via or a filled cap is used as the connection portion, this is not limiting, and a combination of a via and a filled cap may also be used.

[0049] (Third embodiment) 5 and 6, the element mounting board, the vehicle lamp, and the element mounting method according to this embodiment will be described. This embodiment differs from the above-described embodiment in that a land bridging portion that connects the divided lands or an electrode bridging portion that connects the divided electrodes is provided, so that the divided lands or the divided electrodes are at the same potential. Therefore, the vehicle lamp and the element mounting method are the same as those of the above-described embodiment, and therefore will not be illustrated, so please refer to FIGS. 1 to 3 if necessary.

[0050] An example of the configuration of the light-emitting element 10 according to this embodiment will be described with reference to Fig. 5(a). As shown in Fig. 5(a), the light-emitting element 10 according to this embodiment includes an LED 31, a phosphor 32, a bump 33, a resin 34, a circuit pattern 35, a circuit pattern 36, an inner layer pattern 37, and a substrate 38.

[0051] The phosphor 32 is disposed on the light-emitting surface of the LED 31 and converts the wavelength of part of the light emitted from the LED 31. The wavelength-converted light is mixed with the light emitted from the LED 31 and emitted as emitted light L of a desired color from the light-emitting element 10. For example, by using a blue LED as the LED 31 and a yellow phosphor as the phosphor 32, it is possible to obtain white emitted light L.

[0052] The LED 31 is disposed on a substrate 38. That is, the LED 31 is fixed to a circuit pattern 35 formed on the surface of the substrate 38 via connection means such as bumps 33. The LED 31 is further sealed with a resin 34 disposed on the circuit pattern 35. Meanwhile, the circuit pattern 35, which fixes the LED 31 with the bumps 33, is connected to a circuit pattern 36 on the back surface by an inner layer pattern 37 such as a via. The circuit pattern 36 is divided into a plurality of parts (five in the example of FIG. 5(a)) to form the divided electrode 10b.

[0053] Figure 5(b) shows an example of the split electrodes 10b of the light-emitting element 10. In Figure 5(b), ten split electrodes 10b are arranged on each side, one of which is an anode electrode and the other is a cathode electrode. A copper foil pattern 39 is provided around the split electrodes 10b of the anode and cathode electrodes. Figure 5(c) shows the state in which resist 40 has been applied to the pattern of Figure 5(b).

[0054] As shown in FIG. 5(b), each of the split electrodes 10b is usually isolated from one another. Therefore, the phenomenon described in the second embodiment may occur. In the example shown in FIG. 5(b), the seven outer split electrodes 10b are connected by a copper foil pattern 39, but the three split electrodes 10b arranged in the inner region R are isolated. To connect the isolated split electrodes 10b in the light-emitting element 10 shown in FIG. 5(a), an additional inner layer is required to connect the split electrodes 10b. However, this method may lead to increased costs.

[0055] As explained in the second embodiment, in order to connect the divided lands 20b to each other, an inner layer or a back surface layer is provided in the device mounting board 20, and then the divided lands 20b are connected to the inner layer or the back surface layer by vias or filled caps. In other words, in the second embodiment, the device mounting board 20 needs to have a special shape, which may again result in increased costs. Therefore, in this embodiment, a land bridging portion that connects the divided lands to each other, or an electrode bridging portion that connects the divided electrodes to each other, is provided, and a configuration is adopted in which the divided lands or the divided electrodes are provided at the same potential.

[0056] The land bridging portion 20c and electrode bridging portion 10c according to this embodiment will be described with reference to Fig. 6. Fig. 6 shows the land bridging portion 20c and electrode bridging portion 10c added to the divided land 20b and divided electrode 10b shown in Fig. 3. The land (20a, 20b, 20c) column in Fig. 6 shows the pattern on the surface 23 (see Fig. 1(a)) of the device mounting board 20, and the electrode (10a, 10b, 10c) column in Fig. 6 shows the pattern in the circuit pattern 36 shown in Fig. 5(a).

[0057] For example, the land (20a, 20b, 20c) column for example pattern (a) illustrates two lands 20a (e.g., for an anode electrode and a cathode electrode) each consisting of three split lands 20b. The split lands 20b are connected to each other by a land bridging portion 20c. The "split land 20b" according to this embodiment is defined to include split lands 20b connected by the land bridging portion 20c in this way. In this embodiment, the centers of the opposing sides of adjacent split lands 20b are connected to each other. By providing the land bridging portion 20c in this way, it is possible to make the split lands 20b have the same potential.

[0058] Here, it is assumed that the width W of the land bridging portion 20c in the horizontal direction (the direction of the opposing sides of adjacent split lands 20b in FIG. 6) is shorter than the length C of the opposing sides of adjacent split lands 20b. Furthermore, the width W of the land bridging portion 20c can be set to ½ or less of the horizontal length C of the split land 20b. More preferably, the width W of the land bridging portion 20c can be set to approximately ⅓ of the horizontal length C of the split land 20b.

[0059] The above description has been given for example pattern (a) in the land (20a, 20b, 20c) column shown in FIG. 6 . The same can be applied to example patterns (b) and (c) shown in FIG. 6 . However, for example pattern (b), it is sufficient that the divided lands 20b within the land 20a are connected by the land bridges 20c at the very least, so the unnecessary land bridges 20c can be omitted. Furthermore, example patterns (a), (b), and (c) for the electrodes (10a, 10b, 10c) can be understood in the same way as example patterns (a), (b), and (c) in the land (20a, 20b, 20c) column. In particular, the same applies to the relationship between the horizontal width W of the electrode bridges 10c and the length C of the opposing sides of adjacent divided electrodes 10b.

[0060] <Modification of the third embodiment> The land bridging portion 20c and the electrode bridging portion 10c according to this modification will be described with reference to FIG. 7. The arrangement of the example pattern shown in FIG. 7 is the same as that of the example pattern shown in FIG. 6. Referring to example pattern (a) in the Land (20a, 20b, 20c) column, unlike FIG. 6, the land bridging portion 20c connects positions of the opposing sides of adjacent divided lands 20b that are shifted from the center. With respect to the gap T1 between the left and right lands 20a, the left land bridging portion 20c is shifted to the right, and the right land bridging portion 20c is shifted to the left. In other words, the land bridging portions 20c of the left and right divided lands 20b are shifted toward the gap T1.

[0061] The reason for arranging the land bridging portions 20c in this embodiment with the above-described offset is to improve thermal shock resistance. That is, when a thermal shock occurs due to environmental changes or temperature increases during operation, cracks in the solder enter from the outside of the land 20a. This is illustrated in FIG. 5(d). In FIG. 5(d), the direction of crack propagation relative to the land 20a is indicated by X. Therefore, when providing land bridging portions 20c connecting the split lands 20b, the land bridging portions 20c of the left and right lands 20a are offset in the direction toward the gap portion T1 as described above, thereby further extending the life of the split lands 20b.

[0062] The above has been a description of the example pattern (a) in the column for lands (20a, 20b, 20c) shown in FIG. 7 , but the same can be said for example patterns (b) and (c) as shown in FIG. 7 . However, for example pattern (b), it is sufficient that at least the divided lands 20b within land 20a are connected by land bridging portions 20c, so the unnecessary land bridging portions 20c can be omitted. The example patterns (a), (b), and (c) for electrodes (10a, 10b, 10c) can also be understood based on the above description. In particular, the offset of the left and right electrode bridging portions 10c relative to the gap portion T2 is similar to that for example patterns (a), (b), and (c) in the column for lands (20a, 20b, 20c).

[0063] In the above description of the embodiments, each embodiment has been described independently, but the present invention is not limited to this, and a configuration in which a plurality of embodiments are combined may be used. For example, the second and third embodiments may be combined to form a configuration including both a connecting portion and an electrode bridging portion.

[0064] In addition, in the above embodiment, an example was given in which both the land 20a of the element mounting substrate 20 and the electrode 10a of the light-emitting element 10 include split lands 20b and split electrodes 10b, respectively, but this is not limited to this, and the embodiment may also include at least one of the split lands 20b and split electrodes 10b.

[0065] In the above embodiment, the same number of divided lands 20b are arranged in the same manner within each of the lands 20a of the device mounting substrate 20, but this is not limiting and different numbers and arrangements may be used. For example, by making the number or arrangement of the divided lands 20b different between the anode land 20a and the cathode land 20a, it is possible to prevent, for example, incorrect mounting of the light-emitting element 10. In this case, it is preferable to make the number and arrangement of the divided electrodes 10b of the light-emitting element 10 the same.

[0066] In the above embodiment, the divided lands 20b of the element mounting substrate 20 are rectangular, but the present invention is not limited to this and any suitable shape, such as circular, elliptical, or diamond, may be selected depending on the design conditions. For example, to improve positioning accuracy, the divided lands 20b for the anode may be rectangular, and the divided lands 20b for the cathode may be diamond. In this case, it is preferable that the divided electrodes 10b of the light-emitting element 10 have the same shape. [Explanation of symbols]

[0067] 10...Light emitting element 10a...electrode 10b…divided electrode 10c...Electrode bridging section 11...Light-emitting area 20, 20-1, 20-2...Device mounting board 20a...Land 20b...Split Land 20c…Land Bridge Section 21...Wiring pattern 22...Solder 23…Surface 24...Beer 25...Connecting part (first inner layer) 26...Second inner layer 27...Back layer 28...Field cap 29...Connecting part (back surface layer) 30...Resin 31...LED 32...phosphor 33...Bump 34...Resin 35...Circuit pattern 36...Circuit pattern 37...Inner layer pattern 38... Circuit board 39...Copper foil pattern 40...Resist 50...Vehicle lighting fixtures 51...Reflector 52...Lens 53...heat sink A, B, C, D, E, F...length Cp...Connection position Fs…Surface tension Fh…Horizontal component Fv…Vertical component L...Luminescent light P...Pattern R…Region T1, T2…Gap area W…width X…direction

Claims

1. A device mounting substrate for mounting a light emitting element on a land provided on a surface thereof, the light emitting element having an electrode having a shape corresponding to the land, 10. A device mounting board, wherein the land includes a plurality of divided lands and / or the electrode includes a plurality of divided electrodes.

2. 2. The device mounting board according to claim 1, The device mounting board, wherein each of the divided lands and / or the divided electrodes is a rectangle with at least one side having a length of 0.2 mm or less.

3. 2. The device mounting board according to claim 1, the land includes a plurality of divided lands and the electrode includes a plurality of divided electrodes; the divided lands have substantially the same shape as the divided electrodes, 10. A device mounting board, comprising: a plurality of divided lands arranged within said land in correspondence with the arrangement of a plurality of divided electrodes within said electrode.

4. 2. The device mounting board according to claim 1, The element mounting board is characterized in that a plurality of the lands are provided corresponding to a plurality of electrodes of the light emitting element.

5. 5. The device mounting board according to claim 4, Element mounting board, characterized in that the size of the divided land provided below the light-emitting region of the light-emitting element is larger than the size of the divided land provided below the region other than the light-emitting region.

6. 5. The device mounting board according to claim 4, The divided lands are arranged in a matrix within the land, 10. A device mounting board according to claim 9, wherein the pitch between adjacent divided lands within the land is smaller than the pitch between adjacent lands.

7. 5. The device mounting board according to claim 4, 10. A device mounting board according to claim 9, wherein the pitch between adjacent divided lands within the land is about 1 / 3 of the length of the opposing sides of the adjacent divided lands.

8. 2. The device mounting board according to claim 1, a connecting portion formed by at least one of the inner layer and the back surface layer; a plurality of connecting portions that connect each of the divided lands arranged on the surface layer to the connecting portion;

9. 9. The device mounting board according to claim 8, The device mounting board, wherein the connection portion is at least one of a via and a filled cap.

10. 2. The device mounting board according to claim 1, An element mounting substrate characterized by further comprising at least one of a land bridging portion that connects adjacent split lands of the plurality of split lands with a wiring pattern having a width narrower than that of the split lands, and an electrode bridging portion that connects adjacent split electrodes of the plurality of split electrodes with a wiring pattern having a width narrower than that of the split electrodes.

11. The device mounting board according to claim 10, The land bridging portion connects the approximately central portions of the opposing sides of the adjacent divided lands, and the electrode bridging portion connects the approximately central portions of the opposing sides of the adjacent divided electrodes.

12. The device mounting board according to claim 10, a plurality of the lands corresponding to a plurality of the electrodes included in the light emitting element; The land bridging portion connects positions that are shifted in the gap direction between the lands from the centers of the opposing sides of adjacent divided lands, and the electrode bridging portion connects positions that are shifted in the gap direction between the electrodes from the centers of the opposing sides of adjacent divided electrodes.

13. The device mounting board according to claim 10, The width of the land bridging portion is 1 / 2 or less, preferably approximately 1 / 3, of the length of the opposing sides of the adjacent divided lands, and the width of the electrode bridging portion is 1 / 2 or less, preferably approximately 1 / 3, of the length of the opposing sides of the adjacent divided electrodes.

14. A vehicle lamp comprising: a device mounting board according to claim 1; and a light emitting element mounted on the device mounting board.

15. 1. An element mounting method for mounting a light emitting element on a land provided on a surface, the light emitting element having an electrode having a shape corresponding to the land, the method comprising: A device mounting method characterized in that the land is configured to include a plurality of divided lands and / or the electrode is configured to include a plurality of divided electrodes.

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