JP4385481B2 - Display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a display device and a manufacturing method thereof, and more particularly to a display device using a light emitting diode element.
[0002]
[Prior art]
With the recent rapid development of technology, it is possible to process a large amount of information data, and accordingly, there is an increasing demand for a full-color display device capable of processing and displaying a large amount of image information. One of such display devices uses a light-emitting diode (hereinafter referred to as LED) element. That is, by arranging LED elements that can be driven with high luminance and low voltage in a desired shape such as a matrix and driving each LED element, a display device that can obtain a desired image can be manufactured. JP-A-56-1738, JP-A-5-53511, JP-A-7-335742, JP-A-9-197979, JP-A-10-22529, JP83030661, JP7335942 Many display devices in which LED elements are arranged in a matrix have been proposed as described in JP71229097, JP6232456, JP6045660, and the like.
[0003]
[Problems to be solved by the invention]
By the way, in the process of manufacturing such a display device, it is necessary to mount and wire the LEDs one by one on the large screen. However, this process takes a lot of time and the manufacturing yield is low. There is a problem of becoming.
[0004]
Further, when manufacturing an LED display device, the lead wire wired to the electrode taken out from the light emitting surface side of the LED element may come into contact with, for example, a wafer on which the LED element is formed or another electrode to cause a malfunction. is there. Therefore, an insulating film such as an oxide is formed before cleavage, and a window is opened in the electrode by lift-off, whereby contact with the wired conductor can be prevented. These oxide films can be formed by a vapor deposition method, a sputtering method, a chemical vapor deposition (hereinafter referred to as CVD) method, or the like, but the pn junction is exposed by the vapor deposition method or the sputtering method. Insulation is not sufficient because the film cannot be sufficiently formed on the side surface of the LED element. In the CVD method, a film is also formed on the side surface of the LED element. However, since the film is formed on the side surface of the resist remaining on the electrode for lift-off, the lift-off cannot be performed. In addition, in any film formation method, if handling is considered, cleavage must be performed after film formation, and thus there is a problem that the film is partially peeled off during cleavage.
[0005]
  Accordingly, the present invention has been made in view of the above-described conventional problems, and provides a display device that can easily mount LED elements and electrode wiring, has high production efficiency, and can display a high-quality image. With the goal.
[0006]
[Means for Solving the Problems]
  The display device according to the present invention is based on a rod-shaped substrate in which a plurality of light emitting diode elements are linearly arranged,On the first support substrateBy arranging a plurality of the rod-shaped substrates in the width direction, the light emitting diode elements are arranged in a matrix.A small unit, a second support substrate on which the first support substrate is mounted, a middle unit in which the small units are arranged in a matrix, and a third unit on which the second support substrate is mounted. The above-mentioned middle units are arranged in a matrix.It is characterized by that.
[0007]
In the display device according to the present invention, a plurality of light emitting diode elements as a basic unit are arranged in a straight line, and the light emitting diode elements are arranged in a matrix by arranging a plurality of the rod shaped substrates in the width direction. It is arranged.
[0008]
Therefore, the display device according to the present invention is excellent in production efficiency because the number of steps for mounting the light emitting diode elements and the number of wirings of the electrodes are greatly reduced, and can display a high-quality image with good visibility. it can.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to the drawings. In addition, this invention is not limited to the following examples, In the range which does not deviate from the summary of this invention, it can change suitably.
[0013]
FIG. 1 is a partial longitudinal sectional view showing the structure of an LED display device to which the present invention is applied. The LED display device includes a first substrate 1, a middle unit 2 of LED elements mounted on the first substrate 1 (hereinafter referred to as a middle unit 2), and an LED element mounted on the middle unit 2. A small unit 3 (hereinafter referred to as a small unit 3) is provided.
[0014]
The 1st board | substrate 1 is for mounting the middle unit 2, and is comprised from the material which has insulation. Specifically, a resin or the like can be used as the material used for the first substrate 1. The first substrate 1 is configured so that a predetermined number of medium units 2 can be mounted. For example, nine medium units 2 of vertical 3 × horizontal 3 can be mounted. The portion on the upper surface of the bottom portion of the first substrate 1 where each middle unit 2 is mounted is shaped to be fitted to the lower portion of the middle unit 2, and positioning pin posts 4 provided on the middle unit 2 described later are provided. Positioning holes to be fitted are provided. And the partition 5 for separating and fixing the middle units 2 is provided in the part where the middle units 2 are adjacent to each other. In addition, a fixing bolt hole 7 through which a fixing bolt 6 of the middle unit 2 to be described later passes is provided at the center of the portion where each middle unit 2 is mounted. When the middle unit 2 is mounted on the first substrate 1, the fixing bolt 6 passes through the fixing bolt hole 7 and is fixed to the first substrate 1 by the nut 8. On the other hand, an outer peripheral wall 9 for fixing the middle unit 2 is provided on the outer peripheral portion of the first substrate 1. Therefore, the middle unit 2 is securely fixed to the first substrate 1 by adopting the above configuration.
[0015]
The middle unit 1 is for mounting the small unit 3, and includes the small unit 3, the second substrate 10, the driver chip 11, and the support case 12. The middle unit 2 is configured so that a predetermined number of small units 3 can be mounted. For example, the middle unit 2 is configured to be capable of mounting 9 middle units 2 of vertical 3 × lateral 3. FIG. 2 is a longitudinal sectional view showing the configuration of the middle unit 2.
[0016]
The 2nd board | substrate 10 is for mounting the small unit 3, and is comprised from the material which has insulation. Specifically, a glass epoxy resin or the like can be used as the material used for the second substrate 10. On the surface of the second substrate 10, that is, the main surface on the side where the small unit 3 is mounted, for example, a pattern of gold electrodes is printed as shown in FIG. 3, and through holes 13 are formed at predetermined positions. The small unit 3 mounted by these and the driver chip 11 described later are electrically connected.
[0017]
The driver chip 11 is for driving the LED element, and is arranged on the back surface of the second substrate 10, that is, the main surface opposite to the side on which the small unit 3 is mounted. In this way, by arranging the dedicated driver chip 11 for each middle unit 2 and independently controlling a predetermined number of LED displays, the system clock frequency can be lowered.
[0018]
Further, instead of using the driver chip 11, an electrode pattern for attaching the connector is formed on the back surface of the second substrate 10, that is, the main surface opposite to the side on which the small unit 3 is mounted, as shown in FIG. The connector may be attached and connected to a separately arranged drive circuit.
[0019]
The support case 12 is for protecting the driver chip 11 and the like, and for mounting the middle unit 2 on the first substrate 1 with high accuracy, and is configured to cover the side surface and the lower portion of the second substrate 10. The Below the support case 12, a unit position identification electrode 14 for identifying the position of the unit, a power source 15, a signal bus line 16, and the like are provided. In addition, a fixing bolt 6 for fixing the middle unit 2 to the first substrate 1 is provided in the lower central portion of the support case 12. By using the fixing bolt 6, the middle unit 2 is securely fixed to the first substrate 1. In addition, a positioning pin post 4 that fits into the positioning hole provided in the first substrate 1 described above is provided on the lower outer peripheral portion of the support case 12. The middle unit 2 is accurately and simply placed at a predetermined position on the first substrate 1 by fitting the positioning pin posts 4 and the positioning holes provided in the first substrate 1. , Quality and productivity will be excellent.
[0020]
The small unit 3 is for mounting an LED rod-shaped substrate, and includes an LED rod-shaped substrate and a third substrate.
[0021]
Here, as shown in FIGS. 5 and 6, the LED rod-shaped substrate refers to a rod-shaped substrate in which a plurality of LED elements are linearly arranged on a substrate used for crystal growth of the LED element. FIG. 5 is a plan view of the LED bar substrate, and FIG. 6 is a partially enlarged perspective view of the LED bar substrate. Here, a common n-electrode common to all the elements on the LED rod-shaped substrate is provided on the back surface of the LED rod-shaped substrate, that is, the main surface opposite to the side on which the LED elements are formed. Thus, by forming a common n-electrode for all LED elements on the LED rod-like substrate 16, a simple wiring structure can be taken without requiring complicated wiring. In addition, since no wiring is provided for each LED element, the electrical connection of the wiring is highly reliable.
[0022]
The 3rd board | substrate 17 is for mounting the small unit 3, and is comprised from the material which has insulation. Specifically, a glass epoxy ceramic resin or the like can be used as the material used for the third substrate 17.
[0023]
The third substrate 17 is configured so that a predetermined number of LED rod-shaped substrates 16 can be mounted as shown in FIGS. 7 and 8, for example, a total of 30 LED rod-shaped substrates of 1 vertical × 30 horizontal. 16 can be implemented. In order to mount the LED rod-shaped substrate 16 as shown in FIG. 9, the LED rod-shaped substrate 16 is mounted on the portion of the main surface of the third substrate 17 on the side where the LED rod-shaped substrate 16 is mounted. A guide groove 20 having a width substantially equal to the width of is formed. The LED rod-like substrate 16 is mounted in the guide groove 20 using the connecting means 22 having conductivity.
[0024]
Here, the depth of the guide groove 20 is set to be shallower than the sum of the thickness of the connecting means 22 having conductivity described above, for example, the adhesive film and the LED rod-shaped substrate 16 and deeper than the thickness of the connecting means 22. Is done. When the depth of the guide groove 20 is deeper than the sum of the thickness of the connecting means 22 and the LED rod-like substrate 16, the p electrode formed on the LED element 19, which will be described later, cannot be conducted, or the p electrode This is because it may be difficult to achieve the conduction. If the guide groove 20 is shallower than the conductive connecting means 22, the connecting means 22 protrudes from the guide groove 20 when the LED rod substrate 16 is mounted, and the adjacent LED elements 19. This is because there is a risk of electrical continuity.
[0025]
As shown in FIG. 10, an n electrode terminal 21 for driving the LED element 19 is formed along the shape of the guide groove 20 at the bottom of the guide groove 20, and the LED is formed on the n electrode terminal 21. A rod-shaped substrate 16 is mounted.
Thereby, the back surface of the LED rod-shaped substrate 16, that is, the common n electrode provided on the main surface opposite to the side on which the LED element 19 is formed, and the n electrode terminal 21 provided on the guide groove 20 are electrically conductive. It becomes conductive through the connecting means 22 having That is, each LED element 19 and the third substrate 17 are electrically connected.
[0026]
A through hole 23 that also penetrates through the third substrate 17 is formed at a predetermined position of each n-electrode terminal 21. By forming the through-hole 23, the n electrodes are electrically connected together on the back surface of the third substrate 17, that is, the main surface of the third substrate 17 opposite to the surface on which the LED rod substrate 16 is mounted. Can do. Thereby, it is considered that the reliability is excellent as compared with the case where the wiring is applied to each of the LED elements 19 and the n electrodes are electrically connected. One through hole 23 may be formed per one LED rod-like substrate 16, but a plurality of through holes 23 may be formed in order to further improve the reliability of electrical connection.
[0027]
In addition, a partition wall 24 for separating and fixing the LED rod-shaped substrates 16 is provided along a side surface in the longitudinal direction of the LED rod-shaped substrate 16 at a portion where the LED rod-shaped substrates 16 are adjacent to each other. The partition wall 24 is a wide partition wall 25 for every predetermined number of LED rod-shaped substrates 16, for example, every 163 LED rod-shaped substrates, and the partition walls positioned between the wide partition walls 25 are narrow. The partition wall 26 is used. In addition, p electrode terminals 27 are formed on the wide partition walls 25, and the p electrode terminals 27 and the LED elements 19 sandwiched between the p electrode terminals 27 are connected by wires as shown in FIG. By doing so, the electrical connection of the p electrode of each LED rod-shaped board | substrate 16 is performed.
[0028]
In the present invention, as a first modification of the small unit 3, as shown in FIGS. 12 and 13, a transparent substrate 29 having a p-electrode wiring 30 formed of a conductive material is mounted on an LED rod-shaped substrate 16. A structure may be employed in which the p-electrode is electrically connected by being placed on the third substrate 17. Here, in this specification, the transparent substrate 29 means a substrate capable of transmitting visible light. FIG. 12 is a plan view of a first modification of the small unit 3, and FIG.₁-X₂FIG. That is, in the first modification, a transparent substrate 29 in which a linear p-electrode wiring 30 is formed on one main surface with a conductive material is placed on the third substrate 17 on which the LED rod substrate 16 is mounted. The structure is made. At this time, each p-electrode terminal 27 is formed on the wide partition wall 25 and each LED rod-shaped substrate 16, and the p-electrode terminal 27 is aligned in the width direction of the LED rod-shaped substrate 16. Is formed. A transparent substrate 29 is placed on the p electrode terminals 27 so that the p electrode wiring 30 is in contact therewith. With such a structure, the p-electrode terminal 27 of each LED rod-shaped substrate 16 is electrically connected by the p-electrode wiring 30 formed on the transparent substrate 29. And by using the transparent substrate 29 as a board | substrate mounted on the LED element 19, it can take out in a favorable state, without preventing the light emission from the LED element 19. FIG.
[0029]
Further, as a second modification of the small unit 3, in the first modification described above as shown in FIGS. 14 and 15, an opaque substrate 31 is used in place of the transparent substrate 29, and the LED element 19 is mounted. A structure in which the light extraction window 32 is provided in this portion may be adopted. Here, in this specification, the opaque substrate 31 means a substrate that cannot transmit visible light. FIG. 14 is a plan view of a second modification of the small unit 3, and FIG._Three-X_FourFIG. That is, the second modified example has a structure in which an opaque substrate 31 in which a linear p-electrode wiring 30 is formed of a conductive material is placed on a third substrate 17 on which the LED rod-shaped substrate 16 is mounted. The At this time, each p-electrode is formed on the wide partition wall 25 and each LED rod substrate 16, and the p electrode is formed so as to be aligned in the width direction of the LED rod substrate 16. . Then, an opaque substrate 32 is placed on the p-electrode so that the p-electrode wiring 30 is in contact with the conductive connection means 22. Further, the opaque substrate 31 has a structure in which a light extraction window 32 is provided in a predetermined portion overlapping the LED element 19. With such a structure, the p-electrode of each LED rod substrate 16 is electrically connected by the p-electrode wiring 30 formed on the opaque substrate 31. Since the light extraction window 32 is provided on the opaque substrate 31, light emitted from the LED element 19 can be extracted in a good state by the light extraction window 32 without using a transparent substrate.
[0030]
In this case, as shown in FIG. 16, the light extraction window 32 may be provided with an optical lens 33 or a diffusion plate for light diffusion. As described above, by providing the light extraction window 32 with the optical lens 33 and the diffusing plate, the light emitted from the LED element 19 can be prevented from being diffracted, and the light is extracted in a better state. Therefore, a better image can be obtained.
[0031]
Further, as a third modification of the small unit 3, as shown in FIGS. 17 and 18, a bar-shaped wiring 34 made of a conductive material may be arranged on the LED element 19 as the p-electrode wiring 30. FIG. 17 is a plan view of a third modification of the small unit 3, and FIG._Five-X₆FIG.
[0032]
That is, a p-electrode terminal 27 is formed on the wide partition wall 25 and each LED rod-shaped substrate 16 as in the first and second modifications, and the p-electrode terminal 27 is an LED rod-shaped substrate. It is formed so as to be aligned in 16 width directions. Then, a rod-shaped wiring 34 made of a conductive material is arranged as a p-electrode wiring 30 on a straight line connecting these p-electrode terminals 27 so that the rod-shaped wiring 34 and each p-electrode terminal 27 are in contact with each other. Thereby, electrical connection can be established between the p-electrode terminals 27. At this time, a fixture 35 made of an elastic body is attached to both ends of the rod-like wire 34 made of a conductive material, and the rod-like wire is fixed to the third substrate 17 by the elastic force of the fixture 35. It is said. Here, a spring or the like can be suitably used as the fixture 35.
[0033]
In the LED display device configured as described above, the LED rod-shaped substrate 16 is formed by arranging a predetermined number of LED elements 19 in the longitudinal direction of the LED elements 19 on the substrate used for crystal growth of the LED elements 19. And the small unit 3 is formed by arranging this LED rod-shaped board | substrate 16 side by side. Thereby, since it is not necessary to arrange the LED elements 19 one by one, it is excellent in production efficiency.
[0034]
In addition, regarding the electrode wiring, since the common n electrode is provided on the back surface of the LED rod-shaped substrate 16, that is, the side opposite to the side where the LED element 19 is formed, the number of wirings is greatly reduced. The configuration is simplified and the production efficiency and wiring reliability are excellent.
[0035]
The electrode wiring is aggregated on the back surface of each substrate using the through holes 23, and only the minimum electrode wiring exists on the surface of the display screen, so the boundary between the units is conspicuous. As a result, there is no problem that image information cannot be displayed, and a high-quality image with good visibility and good visibility can be displayed.
[0036]
The LED display device configured as described above can be manufactured as follows.
[0037]
First, an epi-wafer is manufactured by molecular beam epitaxy (hereinafter referred to as MBE) method or the like.
[0038]
Next, an LED element is produced on the epiwafer by the following method, and an LED rod-like substrate is produced.
[0039]
First, electrode pads are formed on the epi-wafer. The epi-wafer is cleaned and pretreated with a coupling agent or the like. Next, a resist is applied to the main surface of the epi-wafer on the side where the LED elements are formed by a spin coater, and exposure and development are performed using a photomask corresponding to the size and shape of the electrode pad. Then, after development, for example, Ti and Au are formed into a film thickness of 10 nm and 200 nm, respectively, by evaporation, and electrode pads are formed by performing lift-off with acetone.
[0040]
Next, a transparent electrode is formed. The epi-wafer on which the electrode pad is formed is cleaned and pretreated with a coupling agent or the like. Next, a resist is applied to the main surface of the epiwafer on the side where the LED elements are to be formed using a spin coater, and exposure and development are performed using a photomask corresponding to the size and shape of the transparent electrode to be formed. And after image development, for example, Au is formed into a film with a film thickness of 10 nm by a vapor deposition method, and a transparent electrode is formed by performing lift-off with acetone.
[0041]
Next, element isolation is performed. The epi-wafer on which the transparent electrode is formed is cleaned and pretreated with a coupling agent or the like. Next, a resist is applied to the main surface of the epiwafer on the side where the LED elements are to be formed using a spin coater, and exposure and development are performed using a photomask corresponding to the size and shape of the LED elements to be formed. Then, after development, element isolation is performed, for example, by etching in a mixed solution of hydrogen peroxide and hydrogen peroxide.
[0042]
Next, an insulating film is formed. The epi-wafer from which element isolation has been performed is cleaned and pretreated with a coupling agent or the like. Next, a resist is applied to the main surface of the epiwafer on the side where the LED elements are to be formed using a spin coater, and exposure and development are performed using a photomask corresponding to the size and shape of the transparent electrode to be formed. Then, after development, for example, SiO 2 by sputtering.₂A film is formed to a thickness of 200 nm, and an insulating film is formed by performing lift-off with acetone.
[0043]
Next, the back surface of the epi wafer is polished. A photoresist is applied as a protective film to the surface of the epitaxial wafer on which the insulating film is formed on the side where the electrode pads and the like are formed using a spin coater. Then, the back surface of the epi-wafer, that is, the main surface opposite to the side on which the electrode pad or the like is formed is polished using a polishing machine or the like until the thickness of the LED element 19 becomes about 100 μm, for example.
[0044]
Next, an n-electrode is formed. The oxide film formed on the back surface of the epitaxial wafer subjected to the back surface polishing, that is, the main surface on the polished side is removed by wet etching or the like. Next, the photoresist formed as a protective film on the surface of the epi-wafer, that is, the surface on which the above electrode pads are formed is removed with acetone or the like, and the back surface of the epi-wafer, that is, the main surface on the side subjected to wet etching, for example, Pd , AuGe alloy, Ti, and Au are deposited by vapor deposition to a thickness of about 10 nm, 150 nm, 50 nm, and 400 nm, respectively. Next, for alloying, for example, heat treatment is performed for 5 minutes at a temperature of 180 ° C. in an inert gas atmosphere containing about 24% hydrogen to form an n-electrode.
[0045]
Next, cleavage is performed. In the epi-wafer on which the n-electrode is formed, a scribing device is used to put a marking line for every 191 LED elements in the longitudinal direction of the LED elements 19, and for example, 10 LED elements are placed in the width direction of the LED elements 19. A cleavage line is inserted and cleavage is performed to produce an LED rod-shaped substrate 16 as shown in FIG.
[0046]
Next, a small unit of the LED element 19 is produced. First, a third substrate 17 as shown in FIG. 10 is manufactured using an insulating material. Specifically, a glass epoxy resin or the like can be used as a material used for the third substrate 17.
[0047]
In order to manufacture the third substrate 17, first, a substrate material having a predetermined thickness is cut into a size of, for example, 1 cm in length × 1 cm in width. And the guide groove 20 which has a width | variety substantially equal to the width | variety of the LED rod-shaped board | substrate 16 in order to mount each LED rod-shaped board | substrate 16 in the main surface of the side which mounts the LED rod-shaped board | substrate 16 of the 3rd board | substrate 17, and adjacent LED A partition for separating and fixing the rod-shaped substrates 16 is formed along the longitudinal direction of the LED rod-shaped substrate 16 to be mounted. An n-electrode terminal for driving the LED element 19 is formed on the bottom of the guide groove 20 along the shape of the guide groove 20. Then, a through hole 23 that also penetrates the third substrate 17 is formed at a predetermined position of each n electrode terminal. By forming the through hole 23 in this way, the n electrodes are electrically connected together on the back surface of the third substrate 17, that is, the main surface of the third substrate 17 opposite to the surface on which the LED rod-shaped substrate 16 is mounted. Can be taken. As a result, the number of wirings can be greatly reduced as compared with the case where each of the LED elements 16 is wired and the n electrodes are electrically connected, and the production efficiency can be particularly improved. . Further, the reliability of electrical connection can be improved. At this time, one through hole 23 may be formed on one LED rod-shaped substrate 16, but a plurality of through holes 23 may be formed in order to further improve the reliability of electrical connection. In addition, by using the through hole 23, it is possible to easily connect the drive circuit from the back surface of the third substrate 17 to the drive circuit via the middle unit.
[0048]
The partition walls 24 are formed as wide partition walls 25 every predetermined number of LED rod-shaped substrates 16, for example, every three LED rod-shaped substrates, and the partition walls positioned between the wide partition walls 25 are narrow. The partition wall 26 is formed. Then, the p-electrode terminals 27 are formed on the wide partition walls 25 as follows.
[0049]
First, copper is deposited by 18 μm using a desired metal mask.
Next, using the same mask, Ni and gold are sequentially deposited to a thickness of 0.4 μm and 0.3 μm, respectively, to form a p-electrode terminal 27. The p electrode terminal 27 has a straight line connecting the p electrode terminal 27 formed on the wide partition wall 25 and the p electrode terminal 27 formed on the LED element 19 parallel to the width direction of the LED element 16. It forms so that it may become.
[0050]
Then, a through hole 23 that also penetrates the third substrate 17 is formed at a predetermined position of the p-electrode terminal 27. By forming the through-hole 23 in this way, the electrical connection of the n-electrode is collectively performed on the back surface of the third substrate 17, that is, the main surface of the third substrate 17 opposite to the surface on which the LED rod-shaped substrate 16 is mounted. Can be taken. As a result, it is possible to significantly improve the production efficiency as compared with the case where the n-electrodes are electrically connected by wiring the LED elements 191 one by one, and the reliability of the electrical connection is excellent. can do. At this time, one through hole 23 may be formed on one LED rod-shaped substrate 16, but a plurality of through holes 23 may be formed in order to further improve the reliability of electrical connection. In addition, by using the through hole 23, it is possible to easily connect the drive circuit from the back surface of the third substrate 17 to the drive circuit via the middle unit.
[0051]
Next, the LED rod-shaped substrate 16 produced in the above is mounted in the guide groove 20 of the third substrate 17 using the connecting means 22 having conductivity. As the connection means 22 having conductivity, for example, a conductive adhesive film, silver paste, cream solder or the like can be suitably used. Then, by mounting the LED rod-shaped substrate 16 on the third substrate 17, the wiring of the n-electrode is completed.
[0052]
Next, p-electrode wiring is performed. In order to wire the p-electrode, first, as shown in FIG. 19, the adjacent p-electrode terminals 27 formed on the wide partition wall 25 are wired by wire bonding.
[0053]
Next, as shown in FIG. 20, the wire 28 is pressed onto the p-electrode on the LED element 19 between them using an end needle 36, heating at a predetermined temperature, and applying a pressure not more than the wall opening strength of the LED rod-shaped substrate 16. The wire 28 and the p-electrode terminal 19 on the LED element 19 can be connected by simultaneously applying pressure and ultrasonic waves having a predetermined frequency. Here, the heating temperature, the applied pressure, and the frequency of the ultrasonic wave may be appropriately set depending on the material, dimensions, and the like of the wire 28 and the LED rod-shaped substrate 16. Furthermore, it can connect more reliably by reinforcing using a silver paste.
[0054]
In the case of the first modification of the small unit 3 described above, the p-electrode can be wired as follows.
[0055]
First, an Au stripe having a width of 100 μm and a pitch of 1.0 mm is formed as a p-electrode wiring 30 by a lift-off method at a predetermined position on one main surface of the transparent substrate 29 having substantially the same dimensions as the third substrate 17. Here, as the transparent substrate 29, for example, a transparent glass substrate or the like can be suitably used.
[0056]
Next, a positive photoresist is applied to a thickness of, for example, about 10 μm on the transparent substrate 29 using a spin coater, and heat treatment is performed at a predetermined temperature. Thereafter, exposure is performed using a photomask having a desired pattern, and development is performed. Here, when a transparent glass substrate is used as the transparent substrate 29, since glass and Au have poor adhesion, for example, Ti, Cr or the like is formed as a base layer on the transparent glass substrate to a film thickness of about 5 nm. Adhesion can be improved by forming Au on the underlayer by electron beam evaporation or the like.
[0057]
Next, the Au stripe, that is, the p-electrode wiring 30 can be formed by performing lift-off in acetone.
[0058]
Next, cream solder is disposed on a predetermined portion to be connected to the Au stripe on the transparent substrate 29, the electrode pad on the LED element 19, and the p-electrode terminal 19 of the third substrate 17. Then, the transparent substrate 29 is placed on the small unit substrate using a flip chip bonder so that the main surface of the transparent substrate 29 on which the Au stripe is formed and the LED rod-shaped substrate 16 face each other, and these are connected by reflow.
[0059]
In the case of the second modification of the small unit described above, the p-electrode can be wired as follows.
[0060]
First, as in the first modification, an Au stripe having a width of 100 μm and a pitch of 1.0 mm, for example, is lifted off as a p-electrode wiring 30 on one main surface of an opaque substrate 31 having substantially the same dimensions as the third substrate 17. Form by law. Here, as the opaque substrate 31, a resin or the like can be suitably used.
[0061]
Next, a positive photoresist is applied to the thickness of, for example, about 10 μm on the opaque substrate 31 using a spin coater, and heat treatment is performed at a predetermined temperature. Thereafter, exposure is performed using a photomask having a desired pattern, and development is performed.
[0062]
Next, an Au stripe, that is, a p-electrode wiring can be formed by performing lift-off in acetone.
[0063]
Next, cream solder is disposed on a predetermined portion to be connected to the Au stripe on the opaque substrate 31, the electrode pad on the LED element 19, and the p-electrode terminal 27 of the third substrate 17. Then, the opaque substrate 31 is mounted on the small unit substrate by using a flip chip bonder so that the main surface of the opaque substrate 31 on which the Au stripe is formed and the LED rod-shaped substrate 16 face each other, and these are connected by reflow.
Next, a light extraction window 32 is formed in a portion of the opaque substrate 31 on the LED element 19. The light extraction window 32 can be formed in a portion on the LED element of the opaque substrate by preparing a desired mold and performing injection molding.
Then, by attaching the optical lens 33 and the diffusion plate to the light extraction window 32 formed in the above, it becomes possible to extract light from the LED element 19 in a better state.
In the case of the third modification of the small unit described above, p-electrode wiring can be performed as follows.
[0064]
That is, a p-electrode terminal 27 is formed on the wide partition wall 25 and each LED rod-like substrate 16 as in the first and second modifications. The p-electrode terminal 27 has a wide width. A straight line connecting the p electrode terminal 27 formed on the partition wall 25 and the p electrode terminal 27 formed on the LED element 19 is formed to be parallel to the width direction of the LED element 19. Then, a rod-shaped wiring 34 made of a conductive material is arranged as a p-electrode wiring 30 on a straight line connecting these p-electrode terminals 27 so that the rod-shaped wiring 34 and each p-electrode terminal 27 are in contact with each other. Thereby, electrical connection can be established between the p-electrode terminals 27. At this time, a fixture 35 made of an elastic body is attached to both ends of the rod-like wiring 34 made of a conductive material. And it is set as the structure which applies a pressure between the rod-shaped wiring 34 and a 3rd board | substrate with the elastic force of this fixing tool 35, and makes it contact and fix. Here, a spring or the like can be suitably used as the fixture 35.
[0065]
Next, a protective film is formed. The small unit 3 on which the LED rod-shaped substrate 16 is mounted and the p-electrode wiring is provided has the same shape as the small unit 3 and covers the portion other than the main surface on the side where the LED rod-shaped substrate 16 of the small unit 3 is mounted. Insert into the prepared mold. And a protective film is formed by apply | coating and hardening a protective film material only to the surface of the main surface by the side of the LED rod-shaped board | substrate 16 of the small unit 3 mounted. As the mold material, acrylic or the like can be preferably used. As the protective film, a material having insulating properties, transparency, little curing shrinkage, and heat resistance of about 200 ° C. can be used. An epoxy resin or the like can be suitably used for satisfying such conditions. And after a protective film hardens | cures, a protective film can be formed only in the main surface in which the LED rod-shaped board | substrate 16 of the small unit 3 was mounted by peeling a casting_mold | template.
[0066]
Next, the small unit 3 is mounted on the middle unit 2. The small unit 3 on which the LED rod-shaped substrate 16 is mounted, wired, and protective film is formed is mounted on the second substrate 10 by reflow.
[0067]
On the second substrate 10, a pattern as shown in FIG. 3 is formed in advance on the main surface on the side where the small unit 3 is mounted. The small unit 3 and the middle unit 2 are electrically connected by contacting this pattern with the n electrode and the p electrode drawn out on the back surface of the small unit 3, that is, the surface opposite to the surface on which the LED rod-shaped substrate 16 is mounted. Can be connected.
[0068]
In addition, a through hole 13 is formed in the second substrate 10 so as to conduct to the back surface of the second substrate 10, that is, the main surface opposite to the side on which the small unit 3 is mounted, corresponding to the pattern. By forming the through hole 13, the surface of the second substrate 10, that is, the surface on the side where the small unit is mounted and the back surface, that is, the surface opposite to the side where the small unit 3 is mounted can be conducted.
Next, for example, cream solder is disposed on the main surface of the second substrate 10 on the side where the small unit 3 is mounted, and the small unit 3 is mounted on the middle unit substrate using a flip chip bonder. Then, heat treatment is performed at a predetermined temperature, for example, about 200 ° C., and the small unit and the middle unit 2 are connected. Thereby, the small unit 3 and the middle unit 2 are electrically connected.
[0069]
Next, the driver chip 11 is mounted on the back surface of the second substrate 10, that is, the main surface opposite to the side on which the small unit 3 is mounted. Thereby, the small unit 3 is electrically connected to the driver chip 11 through the middle unit 2 and the above-described through hole 13. At this time, instead of mounting the driver chip 11, the connector mounting as shown in FIG. 4 is performed on the back surface of the second substrate 10, that is, the main surface opposite to the main surface on which the small unit 3 is mounted. The electrode pattern may be formed, a connector is attached, and the electrode pattern may be connected to a separately arranged drive circuit.
[0070]
Next, the support case 12 is mounted so as to cover the side surface and the lower portion of the second substrate 10. A unit position identification electrode 14 for identifying the position of the unit, a power supply 15 and a signal bus line 16 are provided below the support case 12.
[0071]
A positioning pin post 4 that fits into a positioning hole provided in the first substrate 1 is formed on the lower outer peripheral portion of the support case 12.
[0072]
In addition, a fixing bolt 6 for fixing the middle unit 2 to the first substrate 1 is provided in the lower central portion of the support case 12. By using the fixing bolt 6, the middle unit 2 can be reliably fixed to the first substrate 1.
[0073]
Therefore, by attaching the support case 12, the driver chip 11 and the like can be protected, and the middle unit 2 can be simply and accurately mounted on the first substrate 1.
[0074]
Next, the middle unit 3 is mounted on the first substrate 1. At this time, a positioning hole for fitting with the positioning pin post 4 described above is formed at a predetermined position of the first substrate 1. In addition, a fixing bolt hole 7 through which the fixing bolt 6 described above is passed is provided in the central portion of the portion of the first substrate 1 where the middle units 2 are mounted. In addition, when the middle unit 2 is mounted, a partition wall 5 for separating and fixing the middle units 2 is formed in a portion where the middle units 2 are adjacent to each other. On the other hand, an outer peripheral wall 9 is provided on the outer peripheral portion of the first substrate 1 in order to fix the middle unit 2.
[0075]
Then, by fitting the positioning pin posts 4 formed in the middle unit 3 and the positioning holes provided in the first board 1, the middle unit 3 is placed at a predetermined position on the first board 1 with high accuracy and convenience. Can be implemented. At this time, by fixing the fixing bolt 6 through the fixing bolt hole 7 and fixing the fixing bolt 6 to the first substrate 1 with the nut 8, the middle unit 2 can be securely fixed to the first substrate 1. .
[0076]
As described above, a large-screen LED display device can be manufactured.
[0077]
In the LED display device obtained as described above, a predetermined number of LED elements are arranged in the longitudinal direction of the LED elements on the substrate used for crystal growth of the LED elements to form an LED rod-shaped substrate. A small unit is formed by arranging the LED rod-shaped substrates. Thereby, since it is not necessary to arrange the LED elements one by one, it becomes possible to mount the LED elements efficiently and simply.
[0078]
In addition, regarding the electrode wiring, since the common n electrode is provided on the back surface of the LED rod substrate, that is, the side opposite to the side where the LED element is formed, the number of wirings is greatly reduced, It can be performed efficiently and simply, and the production efficiency and the reliability of wiring can be remarkably improved.
[0079]
The electrode wiring is concentrated on the back of each substrate using through holes, and the display screen has only a minimum of electrode wiring on the surface, so the boundaries between the units are conspicuous. Therefore, it is possible to prevent the occurrence of problems such as inability to display image information, and to obtain a display device capable of displaying a high-quality image with good visibility.
[0080]
Further, in the above, in order to prevent a short circuit between the LED element pn junction or between the LED elements, an insulating film is formed on the LED element before the cleavage in the process of manufacturing the LED rod-shaped substrate. An insulating film can be formed by the following method to prevent a short circuit.
[0081]
First, in the manufacturing method described above, the LED rod-shaped substrate 16 is mounted in the guide groove 20, and the n-electrode wiring is finished, and a photoresist is applied to the main surface of the third substrate 17 on the side where the LED rod-shaped substrate 16 is mounted. Apply with a spin coater.
[0082]
Next, the electrode pad of the LED element 19 is exposed using a light beam. The exposure can be performed, for example, by directly drawing on the electrode with a laser beam using an optical direct drawing device 37 shown in FIG. The optical direct drawing apparatus 37 will be briefly described. The optical direct drawing apparatus 37 includes a laser beam transmitter 38, a galvano mirror 39, and an XY stage 40. The LED rod-shaped substrate 16 is mounted on the XY stage 40. It is fixed at a predetermined position. The laser beam oscillated from the laser beam transmitter 37 is irradiated to a predetermined position of the LED rod-shaped substrate 16 placed on the XY stage 40 via the galvano mirror 39, and exposure is performed. Scanning of the laser beam is performed by the galvanometer mirror 39 in the X direction, that is, in the width direction of the LED rod-shaped substrate 16, and scanning in the Y direction, that is, in the longitudinal direction of the LED rod-shaped substrate 16, is placed on the LED rod-shaped substrate 16. This is done by moving the XY stage 40. Here, a Kr laser having an oscillation wavelength of 413 nm or the like can be suitably used as the light beam. Then, the insulating film 41 is formed on the main surface of the third substrate on which the LED rod-shaped substrate 16 is mounted by performing development with a predetermined developer.
[0083]
In this manner, by forming the insulating film 41 on the main surface of the third substrate 17 on the side where the LED rod-shaped substrate 16 is mounted, not only the insulating effect on the LED element 19 but also the third substrate 17 is formed. The insulation effect between the wirings on the main surface on the side where the LED rod-shaped substrate 16 is mounted can also be obtained.
[0084]
Further, since the groove between the LED rod-shaped substrates 16 is filled with the insulating film 41 on the third substrate 17, an insulation effect can be obtained up to the side surface of the LED rod-shaped substrate 16, so that the pn junction portion of the LED element 19 is short-circuited. Can be prevented.
[0085]
Further, since the grooves between the LED rod-shaped substrates 16 are filled with the insulating film 41 on the third substrate 17, it is possible to perform wiring by screen printing when performing p-electrode wiring, thereby improving production efficiency. be able to. The p-electrode wiring may be performed by wire bonding.
[0086]
In addition, since exposure is performed by direct drawing with a light beam using the optical direct drawing device 37, the position of the LED rod-shaped substrate 16 is shifted on the third substrate 17, or the thickness of the LED rod-shaped substrate 16 is increased. Even when there is a variation, the exposure can be performed with good accuracy without being affected, and the production yield can be remarkably improved.
[0087]
In addition, when there is little misalignment of the LED rod-shaped substrate 16, variation in the thickness of the LED rod-shaped substrate 16, etc., it becomes possible to perform exposure efficiently in a short time by performing exposure using a photomask, Production efficiency can be improved.
[0088]
Therefore, production yield and production efficiency can be improved by using the above method.
[0089]
Further, in the above, exposure is performed by direct drawing using a light beam, but exposure can also be performed by using light that has passed through the photomask using a photomask.
[0090]
Further, the insulating film can be removed by irradiating the insulating film with a light beam having sufficiently high energy necessary for decomposing the insulating film, and the electrode can be exposed from the insulating film.
[0091]
【Example】
Hereinafter, a specific example will be described.
[0092]
Example 1
An LED display device was fabricated based on the above-described embodiment.
[0093]
First, an epi wafer as shown below was produced by MBE method.
Substrate: GaAs (100) Si-doped 1-2 × 10¹⁸cm^-3
Buffer layer: GaAsSi doped 100-200 nm
Buffer layer: ME epitaxial (Zn / Sn25 period)
Buffer layer: ZnSe: Cl 10 nm concentration 1 × 10¹⁸  ~ 2x10¹⁸
Clad layer: ZnMgSSe: Cll 1 μm concentration 2 × 10¹⁷cm^-3
MQW active layer: ZnCdSe3QW 2 nm undoped / ZnSSe
Barrier layer: Undoped about 5nm 2W
Clad layer: ZnMgSSe: N 0.8 nm, concentration 5 × 10¹⁷cm^-3
Na-Nd = 1 × 10¹⁷cm^-3degree
Contact layer: ZnSSe: N 150 nm, concentration 2 × 10¹⁸cm^-3
Na-Nd = 5 × 10¹⁷cm^-3degree
Contact layer: ZnSe: N 130 nm concentration 2 × 10¹⁸cm^-3
Na-Nd = 1 × 10¹⁷cm^-3degree
Contact layer: ZnSe: N 5 nm / ZnTe: N 5 nm SL grade structure Concentration Na—Nd is the same as ZnNd or ZnTe.
Contact layer: ZnTe: N 8 nm, concentration 1 × 10¹⁹~ 1x10²⁰cm^-3
p concentration = 2 × 10¹⁹cm^-3degree
In the above, the composition of ZnCdSe in the active layer was controlled so as to correspond to the emission wavelength of 460 to 540 nm (2.669 to 2.295 eV). The band gap of the ZnMgSSe that is the cladding layer was about 2.88 eV at room temperature. The growth conditions were adjusted as appropriate so as not to lower the carrier concentration in the vicinity of the contact.
[0094]
Next, an LED element was formed on the epitaxial wafer produced above using the following process. One LED element has a shape of 150 × 910 μm and an electrode pad size of 100 × 860 μm, and a window of 60 × 175 μm as shown in FIG. 1 is formed. A plurality of LED elements were formed in a state of being arranged in both vertical and horizontal directions on a single wafer.
[0095]
Electrode pad formation
The epiwafer was cleaned and pretreated with a coupling agent. Next, a resist was applied to the main surface of the epiwafer on the side where the LED elements were to be formed using a spin coater, and exposure and development were performed using a photomask corresponding to the size and shape of the electrode pad. After development, Ti and Au were formed into a film thickness of 10 nm and 200 nm, respectively, by vapor deposition, and lifted off with acetone to form an electrode pad.
[0096]
Transparent electrode formation
Next, the epiwafer on which the electrode pad was formed was washed and pretreated with a coupling agent. And the resist was apply | coated with the spin coater to the main surface by the side of forming the LED element of an epi wafer, and exposure and image development were performed using the photomask corresponding to the magnitude | size and shape of a transparent electrode. And after image development, Au was formed into a film with a film thickness of 10 nm by a vapor deposition method, and the transparent electrode was formed by performing lift-off with acetone.
[0097]
Element isolation
Next, the epiwafer on which the transparent electrode was formed was washed and pretreated with a coupling agent or the like. Next, a resist was applied to the main surface of the epiwafer on the side where the LED elements were to be formed using a spin coater, and exposure and development were performed using a photomask corresponding to the size and shape of the LED elements to be manufactured. Then, after development, element isolation was performed by etching in a mixed solution of hydrogen peroxide and hydrogen peroxide.
[0098]
Insulating film formation
Next, the epi-wafer from which element isolation was performed was washed and pre-treated with a coupling agent. Then, a resist was applied to the main surface of the epiwafer on the side where the LED elements were to be formed using a spin coater, and exposure and development were performed using a photomask corresponding to the size and shape of the transparent electrode to be formed. Then, after development, a 200 nm thick SiO 2 film is formed by sputtering.₂A film was formed and lifted off with acetone to form an insulating film.
[0099]
Backside polishing
Next, a photoresist was applied as a protective film with a spin coater on the surface of the wafer on which the insulating film was formed on which the electrode pads and the like were formed. Then, the back surface of the epi-wafer, that is, the main surface opposite to the side on which the electrode pads were formed was polished until the thickness of the LED element became about 100 μm using a polishing machine or the like.
[0100]
Formation of n-electrode
Next, the oxide film formed on the back surface of the epitaxial wafer subjected to the back surface polishing, that is, the main surface on the polished side was removed by wet etching or the like. Then, the photoresist formed as a protective film on the surface of the epi-wafer, that is, the surface on which the electrode pads are formed is removed with acetone or the like. An alloy, Ti, and Au were formed in this order by film deposition to a film thickness of 10 nm, 150 nm, 50 nm, and 400 nm, respectively. Furthermore, for alloying, heat treatment was performed at 180 ° C. for 5 minutes in an inert gas atmosphere containing about 24% hydrogen to form an n-electrode.
[0101]
Cleavage
Next, on the epi-wafer on which the n-electrode is formed, a scribing device is used to put a marking line every other LED element in the longitudinal direction of the LED element, and for example, 10 LED elements in the width direction of the LED element. Cleavage lines were put in place and cleavage was carried out to produce LED rod-shaped substrates as shown in FIG.
[0102]
Small unit production
A small unit substrate measuring 1 cm in length and 1 cm in width as shown in FIG. 7 was produced, and the LED rod-like substrate produced in the above was mounted in a guide groove of the substrate using a conductive adhesive film. An n-electrode terminal was formed at the bottom of the guide groove as shown in FIG. 10, and a through hole was formed at the end of the n-electrode terminal. Then, the driver chip is made to conduct from the through hole to the back surface of the small unit substrate, that is, the n electrode terminal on the main surface opposite to the LED rod-shaped substrate mounting side, from the back surface of the small unit substrate via the middle unit. The structure can be connected to. In addition, wide barrier ribs and p-electrode terminals were formed every three LED rod-shaped substrates, and through holes were formed in each electrode terminal. Then, the through hole is electrically connected to the p-electrode terminal formed on the back surface of the small unit substrate, that is, the main surface opposite to the side on which the LED rod-shaped substrate is mounted, from the small unit back surface to the drive circuit via the middle unit. The structure is connectable.
[0103]
Small unit mounting and wiring
Wiring of the n electrode was completed by mounting the LED rod-shaped substrate on the small unit substrate using the conductive adhesive film.
[0104]
As shown in FIG. 19, p electrode wiring was first performed by wire bonding between p electrode terminals formed on adjacent wide partition walls. Then, as shown in FIG. 20, the wire and the LED element are formed by pressing the wire against the p-electrode terminal using a probe and applying heating, weighting and ultrasonic waves on the p-electrode terminal on the LED element between them. The upper p-electrode terminal was connected.
[0105]
Formation of protective film
In the above, the small unit on which the LED element is mounted and the wiring of the electrode is applied, and the acrylic mold having substantially the same shape as the small unit configured to cover the small unit other than the main surface on the side where the LED rod-shaped substrate is mounted The epoxy resin was applied only to the surface on the side where the LED rod-shaped substrate of the small unit was mounted. After the epoxy resin was cured, the acrylic mold was peeled off to form a protective film.
[0106]
Production of middle unit
The small unit with the protective film formed thereon was mounted on the middle unit substrate by reflow. Cream solder was placed on the pattern of the medium unit substrate, the small unit was mounted on the medium unit substrate with a flip chip bonder, and the small unit was mounted on the medium unit substrate by heat treatment at a temperature of about 200 ° C. The middle unit substrate has a connector-attached electrode pattern formed on the back surface, that is, the main surface opposite to the side on which the small unit is mounted, and is connected to the drive circuit from here.
[0107]
Medium unit mounting
The medium unit produced above was bonded to a large unit substrate to produce a large screen LED display device.
[0108]
When the image information was displayed on the large screen LED display device manufactured as described above by current driving, an image with high brightness and high color quality could be obtained.
[0109]
In the LED display device obtained above, 10 LED elements are arranged in the longitudinal direction of the LED elements on the substrate used for crystal growth of the LED elements to form an LED rod-shaped substrate. A small unit is formed by arranging the LED rod-shaped substrates. Thereby, it was not necessary to arrange the LED elements one by one, and the LED elements could be mounted efficiently and simply. Also, the electrode wiring may be performed for each LED rod-shaped substrate, and it is not necessary to wire one LED element at a time. Therefore, the electrode wiring can be performed efficiently and easily, and the wiring reliability can be improved. Also improved. The electrode wiring is concentrated on the back of each substrate using through holes, and the display screen has only a minimum of electrode wiring on the surface, so the boundaries between the units are conspicuous. As a result, it was possible to obtain a display device capable of displaying a high-quality image having good visibility and good visibility without causing problems such as inability to display image information.
[0110]
Example 2
The LED rod-shaped substrate cut out by cleavage in Example 1 was coated with a positive photoresist using a spin coater and exposed using an optical direct drawing apparatus as shown in FIG.
[0111]
A Kr laser having an oscillation wavelength of 413 nm was used as the light source. Scanning of the laser beam is performed by a galvanometer mirror in the X direction, that is, in the width direction of the LED rod-shaped substrate, and scanning in the Y direction, that is, the longitudinal direction of the LED rod-shaped substrate, moves the XY stage on which the LED rod-shaped substrate is mounted It was done by letting. The optical system of the direct light drawing apparatus was adjusted so that the power of the laser beam on the LED rod-shaped substrate was about 0.1 mW and the diameter of the laser beam was about 1 μm.
Under the above conditions, 10 LED elements formed on the LED rod-shaped substrate were exposed.
[0112]
After completion of exposure, development is performed, and in a state where the exposed electrode does not have a photoresist as an insulating film, a silver paste is applied under the condition that the pn junction on the side surface of the LED element is short-circuited, and cured by performing heat treatment at 180 ° C. I let you.
[0113]
When a voltage of 4 V is applied between the back surface of the LED rod-shaped substrate manufactured as described above, that is, the main surface opposite to the side where the LED element is formed, and the silver paste, and a current flows, the LED element is green. Good luminescence was obtained. Thereby, after cleaving the LED rod-shaped substrate, it is possible to protect the side surface of the LED element by applying a photoresist to the surface of the LED element and exposing the electrode by exposing with a laser beam. It can be said that short circuiting can be prevented.
[0114]
Example 3
First, the epi wafer produced in Example 1 was prepared.
[0115]
Next, from the respective epi-wafers, when forming the n-electrode, Pd, AuGe alloy, Ti, and Au in this order on the back surface of the epi-wafer, that is, the main surface on which wet etching is performed, are respectively 10 nm, 200 nm, LED elements were formed according to the process shown in Example 1 except that the film was formed by vapor deposition at 50 nm and 200 nm. One LED element has a shape of 150 × 910 μm and an electrode pad size of 100 × 860 μm, and a window of 60 × 175 μm as shown in FIG. 1 is formed. A plurality of LED elements were formed in a state of being arranged in both vertical and horizontal directions on a single wafer. In addition, for each epi-wafer, the LED element is an LED element that emits green light as in Example 1, an LED element that emits blue light using ZnCdSe as an active layer, and a red light emitting that uses AlGaInp fabricated in the same manner as an active layer. The LED element which shows this was produced, and three types of wafers, the wafer for green light emission, the wafer for blue light emission, and the wafer for red light emission, were produced.
[0116]
Next, each wafer was cleaved in the same manner as in Example 1 to produce an LED bar substrate having a width of 200 μm, a length of 10 mm, and a thickness of 100 μm.
[0117]
Next, as shown in FIG. 22, the red LED rod substrate 42, the green LED rod substrate 43, and the blue LED rod substrate 44 are used for the small unit substrate in the width direction of the LED rod substrate. Ten green LED rod substrates, blue LED rod substrates, and red LED rod substrates were mounted in this order.
[0118]
Next, a photoresist serving as an insulating film is applied onto a small unit substrate by a spin coater, and the electrode pad is directly drawn by a laser beam in the same manner as in Example 2 using the optical direct drawing apparatus shown in FIG. Exposure was performed. After the exposure, development was performed to form an insulating film.
[0119]
Next, on the small unit substrate on which the insulating film is formed, p electrode wiring is wired between the p electrodes on the small unit adjacent in the width direction of the LED rod substrate by screen printing using a striped metal mask. To make a small unit.
[0120]
Next, a simple matrix RGB display device capable of full color display was fabricated by bonding nine small units into a matrix of 3 vertical and 3 horizontal.
[0121]
When the simple matrix RGB display device obtained as described above was displayed with image information by current driving, an image with high luminance and high color quality could be obtained.
[0122]
Moreover, since the groove between the LED rod-shaped substrates is filled with an insulating film on the small unit substrate, an insulation effect can be obtained up to the side surface of the LED rod-shaped substrate, so that a pn junction short-circuit of the LED element can be prevented. High quality images could be obtained.
[0123]
In addition, since the grooves between the LED rod-shaped substrates are filled with an insulating film on the small unit substrate, when performing p-electrode wiring, it is possible to perform wiring by screen printing, which can improve the production efficiency. .
[0124]
In addition, since exposure was performed by direct drawing with a light beam using an optical direct drawing apparatus, the exposure could be performed with good accuracy and good quality, and the production yield could be improved.
[0125]
【The invention's effect】
As described above in detail, the display device according to the present invention is based on a bar-shaped substrate in which a plurality of light-emitting diode elements are linearly arranged and formed, and a plurality of the bar-shaped substrates are arranged in the width direction. The light emitting diode elements are arranged in a matrix.
[0126]
Therefore, the display device according to the present invention is excellent in production efficiency because the number of steps for mounting the light-emitting diode elements and the number of wirings of the electrodes are greatly reduced, and is a high-quality display capable of displaying a high-quality image with good visibility. It becomes a device.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal sectional view showing a structure of an LED display device to which the present invention is applied.
FIG. 2 is a longitudinal sectional view showing a configuration of a middle unit.
FIG. 3 is a diagram illustrating an example of a pattern of cream solder printed on a main surface on a side where a middle unit of a second substrate is mounted.
FIG. 4 is a diagram illustrating an example of a pattern of cream solder printed on a main surface opposite to a side on which a middle unit of a second substrate is mounted.
FIG. 5 is a plan view of an LED rod-shaped substrate.
FIG. 6 is a perspective view of an LED rod-shaped substrate.
FIG. 7 is a plan view of a small unit.
FIG. 8 is a partially enlarged view of a small unit.
FIG. 9 is a cross-sectional view of a main part of a small unit.
FIG. 10 is a perspective view of main parts of a small unit.
FIG. 11 is a cross-sectional view of a main part of a small unit.
FIG. 12 is a plan view of a principal part of a first modification of the small unit.
FIG. 13 is a cross-sectional view of main parts of a first modification of the small unit.
FIG. 14 is a plan view of an essential part of a second modification of the small unit.
FIG. 15 is a cross-sectional view of main parts of a second modification of the small unit.
FIG. 16 is a cross-sectional view of main parts of a second modification of the small unit.
FIG. 17 is a plan view of relevant parts of a third modification of the small unit.
FIG. 18 is a cross-sectional view of main parts of a third modification of the small unit.
FIG. 19 is a diagram showing a state in which p electrode terminals on a wide partition wall are connected by a wire.
FIG. 20 is a diagram showing a state where a p-electrode terminal on a wide partition and a p-electrode terminal on an LED element are connected by a wire.
FIG. 21 is a schematic configuration diagram showing a configuration of an optical direct drawing apparatus.
FIG. 22 is a diagram showing a state where p-electrode terminals formed in a small unit are connected by a screen printing method using a metal mask.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st board | substrate, 2 middle unit, 3 small unit, 4 positioning pin post, 5 partition, 6 fixing bolt, 7 fixing bolt hole, 8 nut, 9 outer peripheral wall, 10 2nd board | substrate, 11 driver chip, 12 support case , 13 Through hole, 16 LED rod-shaped substrate, 17 Third substrate, 18 Substrate used for crystal growth, 19 LED element, 20 guide groove, 21 n electrode terminal, 25 wide partition, 26 narrow partition, 27 p electrode terminal, 28 wires, 29 transparent substrate, 30 p electrode wiring, 31 opaque substrate, 32 light extraction window, 33 optical lens, 34 rod-shaped wiring, 35 fixture

Claims (13)

A basic unit is a rod-shaped substrate in which a plurality of light emitting diode elements are linearly arranged,
By arranging a plurality of the rod-shaped substrates in the width direction on the first support substrate, a small unit in which the light-emitting diode elements are arranged in a matrix,
A second support substrate on which the first support substrate is mounted; a middle unit in which the small units are arranged in a matrix; and
A display device, comprising: a third support substrate on which the second support substrate is mounted, wherein the middle units are arranged in a matrix. The back side of each rod-like substrate, the common electrode is provided, by placing on the first supporting substrate, placement of the rodlike substrate of said first support substrate of the plurality of light emitting diode elements Electrically connected to electrodes provided on the surface ,
The electrode provided on the mounting surface of the rod-shaped substrate of the first support substrate is led to the back surface side of the first support substrate through a through hole, and a drive circuit provided on the second support substrate; The display device according to claim 1, wherein the display device is connected.   3. The display device according to claim 2, wherein the first support substrate is used as one drive unit, and an independent drive circuit is provided for each of one or a plurality of drive units. The first support substrate has a guide groove for positioning the rod-shaped substrate corresponding to the shape of the rod-shaped substrate,
An electrode is formed on a convex portion of the first support substrate formed around the guide groove, and is connected to an individual electrode of a light emitting diode element formed on the rod-shaped substrate. 3. The display device according to 3.   The electrode formed on the convex portion of the first support substrate and the individual electrode of the light-emitting diode element formed on the rod-shaped substrate have a wiring base provided with electrode wiring on one main surface, and the electrode wiring. 5. The display device according to claim 4, wherein the main surface of the rod-shaped substrate on the side where the light emitting diode elements are arranged is opposed to and disposed on the rod-shaped substrate.   6. The display device according to claim 5, wherein the wiring board is capable of transmitting visible light. The wiring board is not capable of transmitting visible light, and a light extraction window for extracting light emitted from the light emitting diode element is provided in a predetermined portion overlapping the light emitting diode element. The display device according to claim 5.   8. The display device according to claim 7, wherein an optical lens for diffusing light emitted from the light emitting diode element is disposed in the light extraction window.   8. The display device according to claim 7, wherein a diffusion plate for diffusing light emitted from the light emitting diode element is disposed in the light extraction window.   5. The display according to claim 4, wherein the electrode formed on the convex portion of the first support substrate is led out to the back side of the guide groove of the first support substrate and is connected to a drive circuit. apparatus.   The display device according to claim 10, wherein the electrode formed on the convex portion of the first support substrate is led to the back surface of the first support substrate through a through hole.   The electrode formed on the convex portion of the first support substrate and the individual electrode of the light emitting diode element formed on the rod-shaped substrate are formed by connecting the rod-shaped wiring to the main surface of the rod-shaped substrate on the side where the light-emitting diode elements are arranged. The display device according to claim 4, wherein the display device is arranged and connected on the rod-shaped substrate so as to face each other.   The display device according to claim 12, wherein the rod-shaped wiring includes a fixture made of an elastic body at both ends, and is fixed to the first support substrate by an elastic force of the fixture.

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