Multilayer substrate structure and display device

Abstract

This invention provides a multilayer substrate structure that improves heat dissipation while suppressing mounting defects in light-emitting devices. [Solution] The multilayer substrate structure 100 of the present invention comprises an LED device 10 having a plurality of electrodes 30R, 30G, 30B, and 30C formed on its terminal surface, and a multilayer substrate 200 on which the plurality of LED devices 10 are mounted. A metal pattern Q1 including electrode pads R, G, and B for connecting each electrode of the LED device 10 is formed on the surface of the uppermost substrate 210. Another metal pattern Q2, Q3, and Q4 are formed on the surfaces of the remaining substrates 220, 230, and 240 of the multilayer substrate so that the number of metal layers located directly beneath each electrode of the LED device 10 is consistent.

Description

Technical Field

[0001] The present invention relates to a display device in which a plurality of light-emitting elements are arranged on a substrate, and particularly to the structure of a multilayer substrate on which micro light-emitting diodes (LEDs) are mounted.

Background Art

[0002] In recent years, micro LEDs that can directly display images from light-emitting diodes have been developed. Micro LEDs are arranged two-dimensionally to correspond to each pixel. For example, the anodes of each light-emitting diode are commonly connected to data wiring, the cathodes are connected to scan wiring, and each of the light-emitting diodes is driven (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=�4]] Display devices such as LCDs and OLEDs are manufactured with a structure using a hard substrate such as glass and cannot be bent. In recent years, however, curved displays have been commercialized by melting and thinning the glass and forcibly attaching / fixing it along the housing to enhance the immersion feeling. In addition, the development and commercialization of display devices that form circuits and mount micro LEDs on a flexible base material such as a film are being considered.

[0005] Figure 1(A) is a top view of the LED device, Figure 1(B) is a bottom view of the LED device, Figure 1(C) shows the connection of the common cathode, and Figure 1(D) shows the connection of the common anode. The LED device 10 has, for example, a rectangular package and contains three light-emitting elements that output red (R), green (G), and blue (B) light. As shown in Figure 1(A), the top surface 12 of the package includes the light-emitting parts 20R, 20G, and 20B of the R, G, and B light-emitting elements, with one LED device 10 constituting one pixel, and the R, G, and B light-emitting elements constituting a subpixel.

[0006] The bottom surface 14 of the LED device 10 is provided with electrodes 30R, 30G, 30B, and 30C, respectively, for R, G, B, and C (common). Electrode 30R is electrically connected to the R light-emitting element, electrode 30G is electrically connected to the G light-emitting element, electrode 30B is electrically connected to the B light-emitting element, and electrode 30C is electrically connected in common to the cathode or anode of the R, G, and B light-emitting elements. The arrangement, shape, and size of electrodes 30R, 30G, 30B, and 30C are arbitrary, but their heights are generally equal. Electrode 30C is made larger than electrodes 30R, 30G, and 30B to allow manufacturers to verify the orientation during the manufacturing process or to enable users to check the orientation of the actual product, or to improve heat dissipation in the case of a common cathode connection as shown in Figure 1(C), since the cathode side of the LED gets hot.

[0007] As shown in Figure 1(C), in common cathode mode, the cathode electrodes of the R, G, and B light-emitting elements are connected to electrode 30C in common, and the anode electrodes of the R, G, and B light-emitting elements are connected to electrodes 30R, 30G, and 30B, respectively. On the other hand, in common anode mode, as shown in Figure 1(D), the anode electrodes of the R, G, and B light-emitting elements are connected to electrode 30C in common, and the cathode electrodes of the R, G, and B light-emitting elements are connected to electrodes 30R, 30G, and 30B, respectively. The LED device 10 may be driven in either common cathode mode or common anode mode.

[0008] When the substrate on which the LED device is mounted is not a rigid substrate (a normal hard printed circuit board) but a flexible substrate made by laminating multiple thin films such as polyimide or PET, the following challenges arise. 1. The more multilayered the structure, the more the thickness differs between areas with and without the circuit board pattern (copper foil). 2. Due to differences in thickness, the circuit pattern and electrodes cannot be connected even when the LED device is mounted. (Open state) 3. Due to differences in thickness, when an LED device is mounted, the LEDs tilt, causing the emitted light axis to tilt, which reduces the front brightness. 4. Due to differences in thickness, when the LED device is mounted, the LEDs may tilt, and some electrodes may not be soldered. (Open state) 5. Due to differences in thickness, when the LED device is mounted, the LED will be tilted, causing the wrong electrodes to make contact with the circuit pattern. (Short circuit) 6. If the cathode's heat dissipation pattern is drawn from the L1 layer (outermost layer), heat will not be distributed uniformly, causing the components to shift. 7. When LED devices are mounted with a narrow pitch, it is not possible to efficiently dissipate the heat from the cathode, which becomes hot.

[0009] Problem 1 will be explained with reference to Figure 2. Figure 2(A) is a cross-sectional view of a multilayer substrate on which an LED device is mounted. For the sake of simplicity, we will assume that the electrodes 30R, 30G, 30C, and 30B of the LED device 10 are arranged in a linear direction.

[0010] The multilayer substrate 40 includes substrates L1, L2, L3, and L4, which are formed by stacking four film-like substrates. Metal patterns P1, P2, P3, and P4 are formed on the surfaces of substrates L1, L2, L3, and L4, respectively. Through-holes TH filled with metal material are also formed in substrates L1, L2, and L3, and these through-holes TH electrically connect the upper metal pattern to the lower metal pattern.

[0011] The metal pattern P1 is formed at positions corresponding to electrodes 30R, 30G, 30C, and 30B, and electrodes 30R, 30G, 30C, and 30B are connected to the corresponding metal pattern P1 by solder or the like. Electrode 30R is connected to the drive circuit (not shown) by the wiring of the metal pattern P1 on substrate L1, electrode 30G is connected to the drive circuit by the wiring of the metal pattern P2 on the second layer substrate L2, electrode 30C is connected to the drive circuit by the wiring of the metal pattern P4 on the fourth layer substrate L4, and electrode 30B is connected to the drive circuit by the wiring of the metal pattern P3 on the third layer substrate L3.

[0012] Since the multilayer substrate 40 is made up of layers of thin films such as flexible polyimide or PET, when the films are laminated together, as shown in Figure 2(B), the height of the metal pattern P1 on the top layer substrate L1 differs depending on whether or not there is a metal pattern located below it, resulting in different thicknesses for the multilayer substrate 40.

[0013] Figure 3(A) illustrates Problem 2. As explained in Problem 1, if the thickness of the multilayer substrate 40 is different, in other words, if the height of the metal pattern P1 on the substrate L1 is different, even if the LED device 10 is mounted on the multilayer substrate 40, a connection failure (open state) will occur between the metal pattern P1 and the electrodes 30R, 30G, 30C, and 30B. Figure 3(A) shows an example where the LED device 10 is not tilted, but solder 50 is not attached to electrodes 30R and 30G, and it is not connected to the metal pattern P1.

[0014] Figure 3(B) illustrates Problem 3. As explained in Problem 1, if the thickness of the multilayer substrate 40 is different, the LED device 10 will tilt when mounted, causing the emission light axes of the R, G, and B light-emitting parts of the LED device 10 to tilt, resulting in a decrease in front brightness. Figure 3(B) shows an example where electrodes 30R, 30G, 30C, and 30B are connected to the metal pattern P1 via solder 50, but the LED device 10 is tilted and the emission light axis is tilted.

[0015] Figure 4(A) illustrates Problem 4. As explained in Problem 1, due to the different thicknesses of the multilayer substrate 40, when the LED device 10 is mounted, the LED device 10 tilts, resulting in electrodes that are not soldered (open state). Figure 4(A) shows an example where the LED device 10 tilts, causing electrode 30B to become unconnected and preventing the blue light from being illuminated.

[0016] Figure 4(B) illustrates Problem 5. As explained in Problem 1, the different thicknesses of the multilayer substrate 40 cause the LED device 10 to tilt when mounted, resulting in different electrodes coming into contact with the metal pattern P1 (short circuit). Figure 4(B) shows an example where the tilting and displacement of the LED device 10 causes the metal pattern P1 to come into contact with an adjacent electrode, resulting in different colors lighting up or the LEDs not lighting up at all.

[0017] Figure 5(A) is a diagram illustrating problem 6. When the cathode heat dissipation pattern is drawn from the metal pattern P1 of the uppermost substrate L1, heat is not transferred uniformly, causing components to shift, float, or rise, resulting in poor connection between the electrode and the metal pattern. Figure 5(A) shows an example in which the width of the metal pattern P1_C of electrode 30C connected to the cathode is made wider compared to the metal pattern P1 connected to electrodes 30R, 30G, and 30B of the LED device 10, thereby increasing heat dissipation.

[0018] Figures 5(B) and 5(C) illustrate problem 7. When the LED device 10 is mounted at a narrow pitch, it is not possible to efficiently dissipate the heat from the cathode, which becomes hot. As shown in Figure 5(B), when the shape of the LED device 10 is large or the mounting pitch is large, it is possible to use the gaps between the pitches of the LED device 10 to pull out the metal pattern P1_C of the substrate L1 and dissipate heat. However, as shown in Figure 5(C), when the shape of the LED device 10 is small or it is mounted at a narrow pitch, it becomes difficult to use the metal pattern P1 of the substrate L1 to dissipate the heat from the cathode electrode.

[0019] The present invention addresses such conventional problems and provides a multilayer substrate structure and a display device that suppress mounting defects in a light-emitting device while improving heat dissipation.

Means for Solving the Problems

[0020] The multilayer substrate structure according to the present invention includes a light-emitting device having a plurality of electrodes formed on a terminal surface, and a multilayer substrate on which a plurality of light-emitting devices are mounted. On the surface of the uppermost layer substrate of the multilayer substrate, a metal layer for electrically connecting each electrode of the light-emitting device is formed, and on the surface of the remaining substrates of the multilayer substrate, another metal layer is formed so that the number of metal layers located directly below each electrode of the light-emitting device is made uniform.

Effects of the Invention

[0021] According to the present invention, since the metal layers are formed on the surfaces of the respective substrates so that the number of metal layers located directly below each electrode of the light-emitting device is made uniform, the flatness of the surface of the multilayer substrate is improved, and thereby, mounting defects of the light-emitting device can be suppressed. Also, the heat dissipation can be improved by the other metal layers formed on the surfaces of the remaining substrates of the multilayer substrate.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1(A) is a top view of an LED device, FIG. 1(B) is a bottom view of the LED device, FIG. 1(C) is a diagram showing the connection of the cathode common, and FIG. 1(D) is a diagram showing the connection of the anode common. [Figure 2] FIG. 2(A) is a cross-sectional view showing a conventional multilayer substrate structure, and FIG. 2(B) is a cross-sectional view explaining Problem 1 of the conventional multilayer substrate structure. [Figure 3] FIG. 3(A) is a cross-sectional view explaining Problem 2 of the conventional multilayer substrate structure, and FIG. 3(B) is a cross-sectional view explaining Problem 3 of the conventional multilayer substrate structure. [Figure 4] FIG. 4(A) is a cross-sectional view explaining Problem 4 of the conventional multilayer substrate structure, and FIG. 4(B) is a cross-sectional view explaining Problem 5 of the conventional multilayer substrate structure. [Figure 5]Figure 5(A) is a plan view showing the relationship between the LED device and wiring (metal pattern) to explain problem 5 of the conventional multilayer substrate structure, and Figures 5(B) and (C) are plan views showing the relationship between the LED device and wiring (metal pattern) to explain problem 6 of the conventional multilayer substrate structure. [Figure 6] This is a schematic cross-sectional view showing the configuration of a multilayer substrate structure according to an embodiment of the present invention. [Figure 7] Figure 7(A) is a plan view showing the metal pattern of the first layer of the multilayer substrate structure according to this embodiment, and Figure 7(B) is a plan view showing the metal pattern of the second layer of the multilayer substrate structure according to this embodiment. [Figure 8] Figure 8(A) is a plan view showing the third layer metal pattern of the multilayer substrate structure according to this embodiment, and Figure 8(B) is a plan view showing the fourth layer metal pattern of the multilayer substrate structure according to this embodiment. [Modes for carrying out the invention]

[0023] The present invention relates to a multilayer substrate structure for mounting multiple light-emitting devices and a display device (display) using the same. The light-emitting devices include, for example, micro-LEDs within a package, and when the display device displays a color image, the light-emitting devices include R, G, and B micro-LEDs. The multilayer substrate includes a stack of flexible film-like substrates, and metal patterns such as electrode pads, connection pads, dummy pads, or wiring patterns (circuit patterns) are formed on the surface of each substrate. It should be noted that the drawings referenced in the following description include exaggerations to facilitate understanding of the invention and do not directly represent the shape or scale of the actual product. [Examples]

[0024] Figures 6(A) and 6(B) are schematic cross-sectional views of a multilayer substrate structure according to an embodiment of the present invention. Figure 6(A) shows the state before mounting the LED devices, and Figure 6(B) shows the state after mounting the LED devices. The multilayer substrate structure 100 of this embodiment comprises a plurality of LED devices 10 and a multilayer substrate 200 on which the plurality of LED devices 10 are mounted. Such a multilayer substrate structure 100 is used in a display device.

[0025] The LED device 10 is configured similarly to the LED device 10 shown in Figure 1, for example. That is, the LED device 10 contains three light-emitting elements (LEDs) R, G, and B inside a rectangular package. The light-emitting parts 20R, 20G, and 20B of the R, G, and B light-emitting elements are arranged on the top surface (light-emitting surface) 12, and electrodes 30R, 30G, and 30B electrically connected to the R, G, and B light-emitting elements, respectively, and a common electrode 30C are arranged on the bottom surface (terminal surface) 14. The surface heights of electrodes 30R, 30G, 30B, and 30C are approximately the same. The surfaces of electrodes 30R, 30G, 30B, and 30C may be approximately equal to the terminal surface of the package, or they may be slightly higher than the terminal surface. Note that in the LED device 10 shown in Figure 6, the electrodes 30R, 30G, 30B, and 30C are arranged linearly for ease of explanation.

[0026] The multilayer substrate 200 includes a stack of multiple film-like substrates, and a metal pattern is formed on the surface of each substrate. The metal pattern may include wiring patterns or circuit patterns that carry electrical signals for driving the LED device 10, or dummy patterns to improve heat dissipation.

[0027] The substrate material is not particularly limited, but can be made of materials such as polyimide or PET. A metal pattern consisting of a single layer or layers of materials such as Cu, Au, Ag, AgMg, Al, or ITO is formed on the surface of the substrate. The metal pattern is formed, for example, by depositing the metal material and etching it using a photolithography process, or by screen printing. Through-holes TH are also formed in the substrate to provide electrical connections between the upper and lower metal patterns. The through-holes TH are filled with a conductive material, such as Cu.

[0028] The multilayer substrate 200 shown in Figure 6 is composed of, as an example, a stack of four substrates 210, 220, 230, and 240. On the surface of the uppermost substrate 210, a metal pattern Q1 is formed at positions corresponding to the electrodes 30R, 30G, 30B, and 30C of the LED device 10.

[0029] Figure 7(A) is a plan view of the substrate 210, where metal patterns Q1 (Q1_1 to Q1_9) corresponding to 3 rows x 3 columns of LED devices 10 are shown. For example, metal pattern Q1_1 corresponding to one LED device 10 has four rectangular electrode pads R, G, B, and C at positions corresponding to electrodes 30R, 30G, 30B, and 30C. Through-holes TH are formed directly below the center of each of the four electrode pads R, G, B, and C. Through-holes TH are through-holes that penetrate the substrate 210, and by filling the through-holes with a metal material, for example by copper plating the through-holes, it becomes possible to electrically connect the upper and lower metal patterns.

[0030] In this way, electrode pads R, G, B, and C are electrically connected to the through-hole TH directly below them. For the sake of clarity, the through-hole TH is shown as a circular dashed line in Figure 7(A). The rectangular dashed line K represents the outer dimensions when the LED device 10 is mounted. For example, one side of the LED device 10 is 0.43 mm, and the outer dimensions of one electrode are, for example, 0.18 mm.

[0031] A metal pattern Q2 is formed on the surface of the second layer substrate 220. The metal pattern Q2 includes connection pads positioned below the electrode pads R, G, B, and C, a wiring pattern for the light-emitting element R, and a wiring pattern for the light-emitting element G. Figure 7(B) is a plan view of the second layer substrate 220. The metal pattern Q2 includes metal patterns Q2_1 to Q2_9 corresponding to the metal patterns Q1_1 to Q1_9 of the first layer substrate 210, a wiring pattern Q2_R for the light-emitting element R, and a wiring pattern Q2_G for the light-emitting element G.

[0032] For example, a metal pattern Q2_1 corresponding to one LED device 20 includes four connection pads R, G, B, and C. The connection pads R, G, B, and C are located below the upper electrode pads R, G, B, and C and are electrically connected to the upper electrode pads R, G, B, and C via through-holes TH. The shape of the connection pads R, G, B, and C is not particularly limited, but for example, they are circular in shape and have a size that is approximately the same as that of the electrode pads R, G, B, and C.

[0033] Through-holes TH are formed directly beneath the center of connection pads B and C. However, through-holes TH are not formed directly beneath connection pads R and G. The through-holes TH are configured in the same way as the through-holes TH formed on the substrate 210.

[0034] The wiring pattern Q2_R is formed to extend in each row direction of the LED device 20, and one wiring pattern Q2_R is commonly connected to each connection pad R in the same row (e.g., Q2_1, Q2_4, Q2_7). Figure 7(B) illustrates a wiring pattern Q2_R extending in three row directions.

[0035] Similarly, the wiring pattern Q2_G is formed to extend in the direction of each row of the LED device 20, and one wiring pattern Q2_G is commonly connected to each connection pad G in the same row (e.g., Q2_1, Q2_4, Q2_7). Here, an example is shown in which the metal pattern Q2 includes the wiring pattern Q2_R and the wiring pattern Q2_G, but it is not limited to this, for example, the metal pattern Q1 may include a wiring pattern for either the R light-emitting element or the G light-emitting element, and the metal pattern Q2 may include a wiring pattern for either the G light-emitting element or the R light-emitting element.

[0036] A metal pattern Q3 is formed on the surface of the third layer substrate 230. The metal pattern Q3 includes connection pads located below the connection pads B and C of the metal pattern Q2, dummy pads located below the connection pads R and G of the metal pattern Q2, and wiring patterns for the light-emitting elements of B. Figure 8(A) is a plan view of the third layer substrate 230. The metal pattern Q3 includes metal patterns Q3_1 to Q3_9 corresponding to metal patterns Q2_1 to Q2_9, and wiring pattern Q3_B for the light-emitting elements of B.

[0037] For example, a metal pattern Q3_1 corresponding to one LED device 20 includes two connection pads B and C and two dummy pads R and G. The connection pads B and C are located below the connection pads B and C of the upper metal pattern Q2 and are electrically connected to the connection pads B and C of the metal pattern Q2 via through-holes TH. The shape of the connection pads B and C is not particularly limited, but for example, they have a shape that is generally the same as the connection pads B and C of the metal pattern Q2. A through-hole TH is formed directly below the center of the connection pad C. The through-hole TH formed in the substrate 230 is configured in the same way as the through-hole TH formed in the substrate 210.

[0038] The dummy pads R and G are positioned below the connection pads R and G of the metal pattern Q2. The shape of the dummy pads R and G is not particularly limited, but for example, they have a shape that is generally the same as the connection pads R and G of the metal pattern Q2. Since there are no through-holes TH between the dummy pads R and G and the connection pads R and G of the metal pattern Q2, the two are not electrically connected. Dummy pads R and G in the same column direction are interconnected so as to extend in the column direction, and are connected by extensions J that extend into the empty space in the row direction. The extensions J are connected to any one of the connection pads C in the same column. In the example shown in the figure, the left extension J is connected to the connection pad C of metal pattern Q3_7, the central extension J is connected to the connection pad C of metal pattern Q3_5, and the right extension J is connected to the connection pad C of metal pattern Q3_3. The dummy pads R and G and the extensions J improve heat dissipation by expanding the area of ​​the metal pattern connected to the C electrode.

[0039] The wiring pattern Q3_B is formed to extend in each row direction of the LED device 10, and one wiring pattern Q3_B is commonly connected to each connection pad B in the same row (e.g., Q3_1, Q3_4, Q3_7). Figure 8(A) illustrates a wiring pattern Q2_B extending in three row directions.

[0040] A metal pattern Q4 is formed on the surface of the fourth layer substrate 240. The metal pattern Q4 includes a connection pad located below the connection pad C of the upper layer metal pattern Q3, dummy pads R, G, and B located below the dummy pads R, G and connection pad B of the metal pattern Q3, and a wiring pattern for the electrode 30C. Figure 8(B) is a plan view of the fourth layer substrate 240. The metal pattern Q4 includes metal patterns Q4_1 to Q4_9 corresponding to metal patterns Q3_1 to Q3_9, and a wiring pattern Q4_C for the common of the light-emitting elements R, G, and B.

[0041] For example, a metal pattern Q4_1 corresponding to one LED device 10 includes one connection pad C and three dummy pads R, G, and B. The connection pad C is located below the connection pad C of the upper metal pattern Q3 and is electrically connected to the connection pad C of the metal pattern Q3 via a through-hole TH. The connection pad C has a shape that is not particularly limited, but is generally the same as the connection pad C of the metal pattern Q3.

[0042] The dummy pads R, G, and B are located below the dummy pads R, G, and connecting pad B of the upper metal pattern Q3. The dummy pads R, G, and B are not particularly limited, but have generally the same shape as the dummy pads R, G, and connecting pad B of the metal pattern Q3. For example, in one metal pattern Q4_1, the dummy pads R and G are connected to each other, and the dummy pad B is connected to the connecting pad C.

[0043] The wiring pattern Q4_C is formed to extend in the direction of each row of the LED device, and one wiring pattern Q4_C is commonly connected to each connection pad C in the same row (e.g., Q4_1, Q4_2, Q4_3). The wiring pattern Q4_C also connects extensions L that extend in the column direction to fill empty spaces in the column direction. Figure 8(B) illustrates a wiring pattern Q2_B that extends in three row directions. The dummy pads R, G, B and extensions L improve heat dissipation by expanding the area of ​​the metal pattern connected to the C electrode.

[0044] A multilayer substrate 200 is formed by bonding substrates 210, 220, 230, and 240 together. The flatness of the electrode pads R, G, B, and C is improved by aligning the number of metal patterns located directly beneath the electrode pads R, G, B, and C on substrate 210. As shown in Figure 6(B), solder 50 is formed on the electrode pads R, G, B, and C, and the electrodes 30R, 30G, 30B, and 30C of the LED device 10 are connected to the solder 50, so that the LED device 10 is mounted on the multilayer substrate 200.

[0045] The wiring patterns Q2_R, Q2_G, Q3_B, and Q4_C of each layer of the multilayer substrate 200 are connected to a drive circuit (not shown). An LED device 10 located at the intersection of the R, G, and B drive signals applied via the column-direction wiring patterns Q2_R, Q2_G, and Q3_B and a common drive signal (e.g., GND) driven via the row-direction wiring pattern Q4_C is selected, and the illumination of the R, G, and B light-emitting elements of the selected LED device 10 is controlled.

[0046] The multilayer substrate structure 100 according to this embodiment provides the following effects. 1. Even with a multilayer structure, the thickness can be made uniform between areas with and without the substrate pattern (copper foil). 2. Because the thickness can be made uniform, even when an LED device is mounted, the circuit pattern (metal pattern Q1) and each electrode of the LED device can be reliably connected. 3. Because the thickness can be made uniform, even when an LED device is mounted, the LED device does not tilt, the emitted light axis is oriented in the normal direction, and the front brightness is improved. 4. Because the thickness can be made uniform, even when the LED device is mounted, the LED device will not tilt, and solder can be reliably applied to all electrodes. 5. Because the thickness can be made uniform, even when an LED device is mounted, the LED device will not tilt, and it is possible to prevent the circuit pattern (metal pattern Q1) from contacting / connecting to different electrodes. 6. Because the cathode's heat dissipation pattern is drawn from layers other than the top layer of the substrate, heat is distributed uniformly during mounting, preventing component misalignment. 7. When mounting LEDs at a narrow pitch, heat dissipation from the cathode, which tends to get hot, can be efficiently achieved by using multiple layers. 8. By limiting the metal pattern on the top layer of the substrate to only lands (electrode pads) for connecting the electrodes of the LED device, and by making all of these electrodes the same shape, component misalignment / rotation can be suppressed.

[0047] The shapes and sizes of the electrode pads, connection pads, dummy pads, dummy wiring, and wiring patterns shown in the above embodiment are illustrative examples, and the present invention is not limited thereto. Furthermore, in the above embodiment, the number of metal patterns Q1, Q2, Q3, and Q4 located directly beneath each electrode of the LED device was matched with the number of layers in the multilayer substrate, but the number of metal patterns located directly beneath each electrode of the LED device does not necessarily have to match the number of layers in the multilayer substrate. In short, it is sufficient that the number of metal patterns located directly beneath each electrode of the LED device is the same, and therefore, for example, the number of metal patterns located directly beneath each electrode of the LED device may be less than the number of layers in the multilayer substrate.

[0048] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope of the gist of the invention as described in the claims. [Explanation of Symbols]

[0049] 10: LED device 30R, 30G, 30B, 30C: Electrode 100: Multilayer board structure 200: Multilayer board 210, 220, 230. 240: Substrate Q1, Q2, Q3, Q4: Metal pattern Q2_R, Q2_G, Q3_B, Q4_C: Wiring patterns TH: Through-hole

Claims

1. A light-emitting device having multiple electrodes formed on its terminal surface, It has a multilayer substrate on which multiple light-emitting devices are mounted, A metal layer is formed on the surface of the uppermost layer of the multilayer substrate for electrically connecting each electrode of the light-emitting device. A multilayer substrate structure in which another metal layer is formed on the surface of the remaining substrate of the multilayer substrate so that the number of metal layers located directly beneath each electrode of the light-emitting device is the same.

2. The multilayer substrate structure according to claim 1, wherein an equal number of other metal layers are formed directly beneath each electrode of the light-emitting device.

3. The multilayer substrate structure according to claim 1, wherein the light-emitting device includes light-emitting elements that output red (R), green (G), and blue (B) light, and the plurality of electrodes include an R electrode electrically connected to the R light-emitting element, a G electrode electrically connected to the G light-emitting element, a B electrode electrically connected to the B light-emitting element, and a C electrode common to the cathodes or anodes of the three R, G, and B light-emitting elements.

4. The multilayer substrate structure according to claim 3, wherein the lowest metal layer formed on the surface of the lowest layer substrate of the multilayer substrate includes a metal layer electrically connected to the C electrode.

5. The multilayer substrate structure according to claim 4, wherein the lowest metal layer includes a dummy metal layer located directly beneath the electrodes of the light-emitting device.

6. The multilayer substrate structure according to claim 5, wherein another dummy metal layer electrically connected to the dummy metal layer is formed on the surface of an intermediate substrate between the uppermost and lowermost layers of the multilayer substrate.

7. The multilayer substrate structure according to claim 3, wherein the multilayer substrate comprises a stack of four substrates, the metal layers formed on the surfaces of the second and third substrates each contain wiring for R, G, and B light-emitting elements, and the metal layer formed on the surface of the fourth substrate contains common wiring for R, G, and B light-emitting elements.

8. The multilayer substrate structure according to claim 1, wherein the multilayer substrate includes a stack of flexible film-like substrates.

9. A display device comprising the multilayer substrate structure described in any one of claims 1 to 8.

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