JP2014072215A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of being manufactured through a small number of process steps, thereby capable of achieving high yield.SOLUTION: In an LED display, first and second light emitting diodes (5, 6) which have different electrical connection polarities each other relative to first and second electrodes (2, 3) are arranged in a matrix form on a substrate (1) in a state where the first and second light emitting diodes (5, 6) are mingled at random while the polarities are not aligned. When a solution including a plurality of the light emitting diodes (5, 6) are coated on the substrate (1) and a voltage is applied between the first and second electrodes (2, 3), the light emitting diodes (5, 6) can be electrically connected to the first and second electrodes (2, 3).

Description

  The present invention relates to a display device using light emitting diodes.

  Conventionally, as a display device using a light emitting diode, as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-273596), a plurality of the plurality of light emitting diodes are arranged on a pressure-sensitive adhesive layer of a transfer substrate from a temporary holding substrate in which a plurality of light emitting diodes are arranged. There are those in which a large number of light emitting diodes finally forming pixels of a display device are arranged in a matrix by repeating the transfer of the light emitting diodes.

  However, the display device has the following problems (i) and (ii).

  (i) The number of light-emitting diodes required in the display device is, for example, 1920 × 1080 × 3 (RGB) = 6220800 when a full-spec high-definition TV receiver is to be realized. Therefore, repeating the transfer of the light emitting diodes increases the number of processes and increases the TAT (Turn Around Time).

  (ii) The process of arranging light emitting diodes with the number of pixels necessary for display display by repeating the peeling of the light emitting diodes from the temporary holding substrate and the transfer of the light emitting diodes to the transfer substrate results in a high yield. There is a problem that it is difficult to obtain.

JP 2004-273596 A

  Therefore, an object of the present invention is to provide a display device that can be manufactured with a small number of steps and can improve a high yield.

In order to solve the above problems, a display device according to the present invention provides:
A substrate,
A first electrode formed on the substrate;
A second electrode formed on the substrate;
A plurality of plate-shaped or bar-shaped light emitting diodes electrically connected between the first electrode and the second electrode;
The plurality of light emitting diodes are:
A first light emitting diode having an anode electrically connected to the first electrode and a cathode electrically connected to the second electrode;
A second light emitting diode having a cathode electrically connected to the first electrode and an anode electrically connected to the second electrode;
The first light emitting diode and the second light emitting diode are randomly arranged between the first electrode and the second electrode on the substrate without matching the polarity,
The plurality of light emitting diodes are arranged in a matrix on the substrate,
The first electrode is
Of the plurality of light emitting diodes arranged in a matrix, electrically connected to the anodes or cathodes of the plurality of light emitting diodes arranged in the first direction,
The second electrode is
Of the plurality of light emitting diodes arranged in a matrix, electrically connected to the anodes or cathodes of the plurality of light emitting diodes arranged in a second direction intersecting the first direction,
And a drive controller that is electrically connected to the first electrode and the second electrode and drives the first and second light emitting diodes,
The drive control unit
The light emitting diodes in a row composed of a plurality of light emitting diodes arranged in the second direction or a plurality of rows of light emitting diodes adjacent in the first direction so that only the first light emitting diodes emit light. A first drive control for passing a current through the first and second electrodes;
The light emitting diodes in a row composed of a plurality of light emitting diodes arranged in the second direction or the light emitting diodes in a plurality of rows adjacent in the first direction so that only the second light emitting diodes emit light. A second drive control for passing a current through the first and second electrodes;
Between the first drive control and the second drive control, one row of light emitting diodes adjacent to the one row of light emitting diodes arranged in the second direction or one row from the plurality of rows of light emitting diodes. A third drive control is performed in which a current is supplied to the first and second electrodes so that only the first light emitting diodes of the plurality of light emitting diodes shifted from each other emit light.

  In the display device according to the present invention, the first and second light emitting diodes having different electrical connection polarities with respect to the first and second electrodes are arranged in a matrix on the substrate in a state where the polarities are not aligned and are mixed randomly. Is arranged. According to the present invention, when a solution containing the plurality of light emitting diodes is applied onto a substrate and a voltage is applied between the first and second electrodes, the plurality of light emitting diodes are applied to the first and second electrodes. Can be electrically connected.

  Therefore, according to the present invention, the number of processes can be reduced and the yield can be improved while suppressing the occurrence of defects in the light emitting diodes, compared to the conventional example in which it is necessary to repeat the process of transferring a plurality of light emitting diodes between substrates. it can.

  In the present invention, the drive control unit causes the first diode in a certain row range to emit light by the first drive control, and then causes the first diode in the other row range to emit light by the third drive control. Then, the second diode in the certain row range is caused to emit light by the second drive control. By such light-emitting diode drive control, the number of times of switching the energization direction can be reduced and the unit time per unit time can be reduced as compared with the case where the second diode emits light after the first diode emits light in a certain row range. The lighting area can be increased, and the flicker of the image can be reduced.

It is a top view which shows a part of 1st Embodiment of the display apparatus of this invention. It is an equivalent circuit schematic of a part of the first embodiment. It is a perspective view which shows an example of a structure of the light emitting diode of the said 1st Embodiment. It is an end view of the light emitting diode. It is process drawing of the manufacturing method of the light emitting diode of a rod-shaped structure. It is process drawing of the manufacturing method of the light emitting diode of the rod-shaped structure following FIG. 4A. It is process drawing of the manufacturing method of the light emitting diode following FIG. 4B. It is process drawing of the manufacturing method of the light emitting diode following FIG. 4C. It is process drawing of the manufacturing method of the light emitting diode following FIG. 4D. It is a top view which shows a mode that the said some rod-shaped structure light emitting diode was connected between the electrodes formed on the board | substrate. It is a top view which shows a mode that wiring was formed in the electrode on the said board | substrate, and the fluorescent substance was apply | coated to the said light emitting diode. FIG. 3 is a partial equivalent circuit diagram of the first embodiment. It is a partial equivalent circuit diagram explaining the operation of the first embodiment. FIG. 6 is another partial equivalent circuit diagram for explaining the operation of the first embodiment. It is an equivalent circuit schematic of a part of 2nd Embodiment of the display apparatus of this invention. It is a partial equivalent circuit diagram explaining the operation of the second embodiment. FIG. 6 is another partial equivalent circuit diagram for explaining the operation of the second embodiment. It is process drawing of the manufacturing method of the modification of the light emitting diode in the said 1st, 2nd embodiment. It is process drawing of the manufacturing method of the light emitting diode following FIG. 13A. It is process drawing of the manufacturing method of the light emitting diode following FIG. 13B.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a plan view showing a part of an LED display as a first embodiment of the display device of the present invention, and FIG. 2 is an equivalent circuit diagram of a part of the first embodiment.

  As shown in FIG. 1, the first embodiment includes an insulating substrate 1, a first electrode 2 formed on the insulating substrate 1, and a second electrode formed on the insulating substrate 1. And an electrode 3.

  The second electrode 3 extends in the second direction X, and has a plurality of protrusions 3A at predetermined intervals. A plurality of the second electrodes 3 are arranged in a first direction Y substantially orthogonal to the second direction X.

  A plurality of the first electrodes 2 are arranged in the second direction X with a predetermined interval with respect to each protrusion 3 </ b> A of the second electrode 3.

  In the LED display of the first embodiment, the anode A is electrically connected to the first electrode 2, and the cathode is electrically connected to the protrusion 3 </ b> A of the second electrode 3. A plurality of second light emitting diodes 5 and a plurality of second light emitting diodes having a cathode electrically connected to the first electrode 2 and an anode electrically connected to the protrusion 3A of the second electrode 3. And a light emitting diode 6. The first light-emitting diode 5 and the second light-emitting diode 6 are light-emitting diodes having the same structure but have different electrical connection polarities with respect to the first and second electrodes 2 and 3.

  The plurality of first and second light emitting diodes 5 and 6 are arranged in a matrix in the first and second directions Y and X on the insulating substrate 1. The plurality of first and second light emitting diodes 5 and 6 are randomly mixed between the first electrode 2 and the second electrode 3 on the insulating substrate 1 without having the same polarity. Has been placed.

  As shown in FIG. 1, the plurality of first electrodes 2 arranged in the first direction Y are electrically connected to one wiring 7. Although not shown in FIG. 1, an insulating film is formed between the substrate 1 and the wiring 7 and between the first and second electrodes 2 and 3 and the wiring 7. 7 is electrically connected to the first electrode 2 through a through hole (not shown) formed in the insulating film.

  As shown in FIG. 1, any of a red phosphor 11, a green phosphor 12, and a blue phosphor 13 is applied on the plurality of light emitting diodes 5 and 6. The red phosphor 11, the green phosphor 12, and the blue phosphor 13 are arranged in order in the second direction X.

  FIG. 2 shows an equivalent circuit corresponding to FIG. In the first embodiment, the column driving circuit 22 connected to the plurality of wirings 7 electrically connected to the first electrode 2 and the plurality of second electrodes 3 are electrically connected. A row drive circuit 21 is provided. The column drive circuit 22 and the row drive circuit 21 constitute a drive control unit.

  Next, with reference to FIG. 7 to FIG. 9, the contents of control by the drive control unit constituted by the row drive circuit 21 and the column drive circuit 22 will be described. 7 to 9 are partial equivalent circuit diagrams of the first embodiment.

  7 to 9, the plurality of wirings 7 electrically connected to the first electrode 2 are represented as data lines DL1, DL2, DL3,..., DLn, respectively. The two electrodes 3 are represented as scanning lines SL1, SL2, SL3,. Here, n in the DLn is a predetermined natural number and represents the nth data line. Further, m in SLm is a predetermined natural number and represents the mth data line. In the case of a high-quality LED display, n and m are numbers of 1000 or more, respectively, as an example.

  First, the first and third drive control at time t = t1 to t4 by the row drive circuit 21 and the column drive circuit 22 forming the drive control unit will be described.

  The row driving circuit 21 applies 0V to the scanning line SL1 at time t = t1, and the other scanning lines SL2 to SLm are set to Hi-Z (high impedance state), while the column driving circuit 22 is set to 0V. 4 V is applied to each of the data lines DL1 to DLn that has been applied. Here, the column drive circuit 22 performs PWM (pulse width modulation) control for controlling the time for applying 4 V to the data lines DL1 to DLn in accordance with the data to be displayed. When the 4V application time ends, the column drive circuit 22 applies 0V to the data lines DL1 to DLn to which 4V has been applied.

  Next, at time t = t2, the row driving circuit 21 applies 0 V to the scanning line SL2, and the other scanning lines SL1, SL3 to SLm are set to Hi-Z (high impedance state), and the column driving is performed. The circuit 22 applies 4V to each of the data lines DL1 to DLn to which 0V has been applied. Here, the column drive circuit 22 performs the same PWM control as described at time t = t1 for each of the data lines DL1 to DLn.

  Next, at time t = t3, the row driving circuit 21 applies 0 V to the scanning line SL3, the other scanning lines SL1, SL2, and SL4 to SLm are set to Hi-Z, and the column driving circuit 22 The same PWM control as described above is performed for each of the data lines DL1 to DLn.

  Next, at time t = t4, the row driving circuit 21 applies 0 V to the scanning line SL4, and the other scanning lines SL1, SL2, SL3, SL5 to SLm are set to Hi-Z and the column driving circuit. 22 performs the same PWM control as described above for each of the data lines DL1 to DLn.

  If the drive control at the time t = t1 is the first drive control, the drive control at the time t = t2 is the third drive control. If the drive control at the time t = t2 is the first drive control, the drive control at the time t = t3 is the third drive control. Similarly, if the drive control at time t = t3 is the first drive control, the drive control at time t = t4 is the third drive control.

  In the control at time t = t1 described above, among the light emitting diodes D11, D12,..., D1n in one row connected to the scanning line SL1, the light emitting diodes D11, D12, D14 having the cathode K connected to the scanning line SL1. , D18... Emit light, while the light emitting diodes D13, D15, D16, D17... With the anode A connected to the scanning line SL1 do not emit light. Here, the light emitting diodes D11, D12,..., D1n in one row represent light emitting diodes connected between the data lines DL1, DL2,..., DLn and the scanning line SL1, respectively.

  In the control at the time t = t2, the light emitting diodes D22, D23 having the cathode K connected to the scanning line SL2 among the light emitting diodes D21, D22,..., D2n connected to the scanning line SL2. , D25, D26, D27, D29... Emit light, while the light emitting diodes D21, D24, D28. Here, the light emitting diodes D21, D22,..., D2n in the one row represent light emitting diodes connected between the data lines DL1, DL2,..., DLn and the scanning line SL2, respectively. The light emitting diode that emits light by the control at the time t = t2 described above is surrounded by a broken line in FIG.

  In the control at the time t = t3 described above, among the light emitting diodes D31, D32,..., D3n connected to the scanning line SL3, the light emitting diodes D31, D32 having the cathode K connected to the scanning line SL3. , D36, D39... Emit light, while the light emitting diodes D33, D34, D35, D37, D38. Here, the light emitting diodes D31, D32,..., D3n in the one row represent light emitting diodes connected between the data lines DL1, DL2,..., DLn and the scanning line SL3, respectively.

  In the control at the time t = t4 described above, among the light emitting diodes D41, D42,..., D4n in one row connected to the scanning line SL4, the light emitting diodes D43, D46 whose cathode K is connected to the scanning line SL4. , D47... Emit light, while the light emitting diodes D41, D42, D44, D45, D48, D49... With the anode A connected to the scanning line SL4 do not emit light. Here, the light emitting diodes D41, D42,..., D4n in the row represent light emitting diodes connected between the data lines DL1, DL2,.

  Thus, in the drive control at the time t = t1, t2, t3, t4, only the first light-emitting diode 5 among the light-emitting diodes in each row connected to the scanning lines SL1, SL2, SL3, SL4 is used. Is emitted.

  Next, drive control at time t = t5 to t8 by the row drive circuit 21 and the column drive circuit 22 forming the drive control unit will be described.

  At time t = t5, the row driving circuit 21 applies 4V to the scanning line SL1, the other scanning lines SL2 to SLm are set to Hi-Z (high impedance state), and the column driving circuit 22 is set to 4V. 0 V is applied to each of the data lines DL1 to DLn that has been applied. Here, the column drive circuit 22 controls the time for applying 0 V to the data lines DL1 to DLn according to the data to be displayed (PWM control). The column drive circuit 22 applies 4V to the data lines DL1 to DLn to which 0V has been applied when the 0V application time ends. The drive control at this time t = t5 forms the second drive control.

  Next, at time t = t6, the row drive circuit 21 applies 4V to the scanning line SL2, and the other scanning lines SL1, SL3 to SLm are set to Hi-Z (high impedance state) and 4V is applied. 0V is applied to each of the data lines DL1 to DLn. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t5 for each of the data lines DL1 to DLn.

  Next, at time t = t7, the row driving circuit 21 applies 4 V to the scanning line SL3, and the other scanning lines SL1, SL2, and SL4 to SLm are set to Hi-Z and the data lines DL1 to DLn. In contrast, the same PWM control as described above is performed.

  Next, at time t = t8, 4V is applied to the scanning line SL4, and the other scanning lines SL1, SL2, SL3, SL5 to SLm are set to Hi-Z, and the column driving circuit 22 is connected to each data line DL1. The same PWM control as described above is performed for .about.DLn.

  If the drive control at the time t = t1 is the first drive control, the drive control at the time t = t5 is the second drive control. If the drive control at time t = t2 is the first drive control, the drive control at time t = t6 is the second drive control. Similarly, when the drive control at time t = t3 is the first drive control, the drive control at time t = t7 is the second drive control.

  In the control at time t = t5 described above, among the light emitting diodes D11, D12,..., D1n in one row connected to the scanning line SL1, the light emitting diodes D13, D15, D16 having the anode A connected to the scanning line SL1. , D17... Emit light, while the light emitting diodes D11, D12, D14, D18... With the cathode K connected to the scanning line SL1 do not emit light.

  Further, in the control at the time t = t6 described above, among the light emitting diodes D21, D22,..., D2n connected to the scanning line SL2, the light emitting diodes D21, D24 whose anode A is connected to the scanning line SL2. , D28... Emit light, and the light emitting diodes D22, D23, D25, D26, D27, D29... With the cathode K connected to the scanning line SL2 do not emit light. A light emitting diode that emits light by the control at the above-described time t = t6 is surrounded by a broken line in FIG.

  Further, in the control at the time t = t7 described above, among the light emitting diodes D31, D32,..., D3n connected to the scanning line SL3, the light emitting diodes D33, D34 having the anode A connected to the scanning line SL3. , D35, D37, D38... Emit light, while the light emitting diodes D31, D32, D36, D39.

  Further, in the control at the time t = t8 described above, among the light emitting diodes D41, D42,..., D4n connected to the scanning line SL4, the light emitting diodes D41, D42 whose anode A is connected to the scanning line SL4. , D44, D45, D48, D49... Emit light, while the light emitting diodes D43, D46, D47... With the cathode K connected to the scanning line SL4 do not emit light.

  Note that the four rows of light emitting diodes connected to the scanning lines SL5 to SL8 also have the same first to third driving controls as those performed on the four rows of light emitting diodes connected to the scanning lines SL1 to SL4. First and second drive control is performed. Thereafter, the first to third drive controls similar to those described above are performed for each of the four rows of light emitting diodes connected to the four scanning lines.

  As described above, the row driving circuit 21 and the column driving circuit 22 are connected to the scanning lines SL1 to SL4 by the first and third driving control at the times t1 to t4 and the second driving control at the times t5 to t8. With respect to the light emitting diodes in the four rows, the first light emitting diodes 5 in the first row to the fourth row are caused to sequentially emit light one row at a time from t1 to t4, and then from the first row to the fourth row from time t5 to t8. The second light emitting diodes 6 of the eyes are caused to emit light one row at a time.

  By such drive control of the light emitting diodes, the number of times of switching the energization direction is compared with the case of performing drive control of causing the second diode to emit light after the first diode emits light for a certain row of light emitting diodes. In addition, the lighting area per unit time can be increased and the flicker of the image can be reduced.

  In the above embodiment, the light emitting diodes that emit light are shifted by one row, but the light emitting diodes that emit light may be shifted by n rows (n is an integer of 2 or more).

  For example, at the times t1, t2, t3, and t4, the first light emitting diodes 5 in the first row, the third row, the fifth row, and the seventh row are caused to sequentially emit one row at a time, and then the time t5, At t6, t7, and t8, the second light-emitting diodes 6 in the first row, the third row, the fifth row, and the seventh row are sequentially caused to emit light one row at a time, and then time t9, t10, t11, and t12. First, the first light emitting diodes 5 in the second row, fourth row, sixth row, and eighth row are sequentially caused to emit light one by one, and then at time t9, t10, t11, and t12, respectively. Control may be performed so that the second light emitting diodes in the fourth, fourth, sixth, and eighth rows sequentially emit light one by one.

  By performing the above control, it is possible to further increase the lighting area per unit time, and to further reduce the flickering of the screen.

  Next, an example of the configuration of the light-emitting diodes 5 and 6 is shown in the perspective view of FIG. 3A. The light-emitting diode as an example includes a cylindrical core portion 31 made of an N-type semiconductor and a cylindrical shell made of a P-type semiconductor that covers the outer peripheral surface 32 of the cylindrical core portion 31. It consists of the part 33. FIG. 3B is an end view showing a state in which the cylindrical core portion 31 is viewed in the axial direction from the end surface 31D side. A part 32 </ b> A of the outer peripheral surface 32 of the cylindrical core portion 31 is exposed from the shell portion 33. The joint surface 35 between the cylindrical core portion 31 and the shell portion 33 is formed concentrically around the cylindrical core portion 31. A portion 31A of the core portion 31 exposed from the shell portion 33 forms the cathode K, and an end portion 33A of the shell portion 33 forms the anode A. 3A and 3B, a light-emitting diode having the configuration shown in FIGS. 3A and 3B is formed in a cylindrical shape along the outer peripheral surface 32 of the core portion 31 with the joint surface 35 between the N-type cylindrical core portion 31 and the P-type shell portion 33. This increases the light emitting surface. Further, since the part 32A of the outer peripheral surface 32 of the core part 31 is exposed from the P-type shell part 33, the electrodes 2 and 3 can be easily connected to the part 32A of the outer peripheral surface 32 of the core part 31. become.

  The end surface 31C of the one end 31B of the core portion 31 may be exposed from the end portion 33A of the shell portion 33, but the end portion 33A of the shell portion 33 covers the end surface 31C of the one end 31B of the core portion 31. By adopting the configuration, the end portion 33A of the shell portion 33 can be easily connected by the electrodes 2 and 3. The semiconductor forming the shell 33 may be N-type, and the semiconductor forming the core 31 may be P-type. 3A and 3B, the core portion 31 has a columnar shape and the shell portion 33 has a cylindrical shape, but may be a polygonal columnar core portion and a polygonal cylindrical shell portion. For example, a hexagonal columnar core portion and a hexagonal cylindrical shell portion, a quadrangular columnar core portion and a rectangular cylindrical shell portion, or a triangular columnar core portion and a triangular cylindrical shell portion may be used. Moreover, it is good also as an elliptic cylindrical core part and an elliptical cylindrical shell part. Moreover, it is good also as a plate-shaped light emitting diode comprised by the plate-shaped core part of rectangular cross-section, and a rectangular-shaped cylindrical shell part.

  Next, with reference to FIGS. 4A to 4E, an example of a manufacturing process of a light-emitting diode including the above-described core portion and shell portion will be described.

  First, as shown in FIG. 4A, a mask 72 having a growth hole 72a is formed on a substrate 71 made of n-type GaN. 4A shows only one growth hole 72a, the mask 72 actually has a plurality of growth holes (not shown) similar to the growth hole 72a.

  Next, as shown in FIG. 4B, in the semiconductor core forming process, an MOCVD (Metal Organic Chemical Vapor Deposition) apparatus is used to form n on the substrate 71 exposed by the growth hole 72a of the mask 72. A rod-shaped semiconductor core 73 is formed by crystal growth of type GaN. Here, the n-type GaN has a hexagonal crystal growth, and a hexagonal columnar semiconductor core can be obtained by growing the n-type GaN in the c-axis direction perpendicular to the surface of the substrate 71. 4B shows only one bar-like semiconductor core 73, actually, a plurality of bar-like semiconductor cores corresponding to the plurality of growth holes of the mask 72 are formed. In the following steps, one rod-shaped semiconductor core 73 is described, but the same steps are performed for other plural rod-shaped semiconductor cores.

  Next, as shown in FIG. 4C, in the semiconductor layer forming step, a semiconductor layer 74 made of p-type GaN is formed on the entire surface of the substrate 71 so as to cover the rod-shaped semiconductor core 73. Next, as shown in FIG. 4D, in the exposure process, the region excluding the portion of the semiconductor layer 74a covering the semiconductor core 73 and the mask 72 are removed by lift-off, and the substrate side of the rod-shaped semiconductor core 73 is moved to the substrate side. The outer peripheral surface is exposed to form an exposed portion 73a. In this state, the end surface of the semiconductor core 73 opposite to the substrate 71 is covered with the semiconductor layer 74a. In the exposure process of this embodiment, lift-off is used, but a part of the semiconductor core may be exposed by etching.

  Next, in the separation step, the base 71 close to the substrate 71 side of the semiconductor core 73 standing on the substrate 71 is bent by vibrating the substrate 71 along the substrate plane using ultrasonic waves (for example, several tens of kHz). Furthermore, stress acts on the semiconductor core 73 covered with the semiconductor layer 74a, and the semiconductor core 73 covered with the semiconductor layer 74a is separated from the substrate 71 as shown in FIG. 4E. In this manner, a fine rod-shaped light emitting diode separated from the substrate 71 can be manufactured. In this method for manufacturing a light emitting diode having a rod-like structure, as an example, the diameter of the rod-like light emitting diode is 1 μm and the length is 10 μm.

  In the manufacturing process of the light emitting diode, a semiconductor using GaN as a base material is used for the substrate 71, the semiconductor core 73, and the semiconductor layer 74a. A semiconductor material may be used. Further, the light emitting diode may have a quantum well structure to improve the light emission efficiency.

  Further, although the substrate and the semiconductor core are n-type and the semiconductor layer is p-type, a rod-shaped structure light emitting diode having a reverse conductivity type may be used. In addition, the method for manufacturing a rod-shaped structure light emitting diode having a semiconductor core with a hexagonal column in the cross section has been described. However, the present invention is not limited to this, and the cross section may be a circular or elliptical rod shape, or the cross section may be another polygon such as a triangle. A bar-shaped light emitting diode having a bar-shaped semiconductor core can also be manufactured by the same manufacturing method as described above. Further, a light emitting diode having a plate structure composed of a plate-shaped core portion having a rectangular cross section and a rectangular cylindrical shell portion can also be manufactured by the same manufacturing method as described above.

  Further, in the above-described light emitting diode manufacturing method, the rod-shaped light emitting diode has a micro-order size of 1 μm in diameter and 10 μm in length. However, as a nano-order size element having at least a diameter of less than 1 μm in diameter or length. Good. The diameter of the semiconductor core of the rod-shaped light emitting diode is preferably 500 nm or more and 100 μm or less, and variation in the diameter of the semiconductor core can be suppressed as compared with the rod-shaped light emitting diode of several tens nm to several hundred nm, and the light emission area, that is, the light emission characteristics Variation can be reduced and yield can be improved.

  In the light emitting diode manufacturing method, the semiconductor core 73 is crystal-grown using the MOCVD apparatus. However, the semiconductor core may be formed using another crystal growth apparatus such as an MBE (molecular beam epitaxial) apparatus. . Further, although the semiconductor core is crystal-grown on the substrate using a mask having a growth hole, the semiconductor core may be crystal-grown from the metal seed by arranging a metal species on the substrate. In the above-described light emitting diode manufacturing method, the semiconductor core 73 covered with the semiconductor layer 74a is separated from the substrate 71 using ultrasonic waves. However, the present invention is not limited thereto, and the semiconductor core is mechanically removed from the substrate using a cutting tool. May be separated. In this case, a plurality of fine rod-shaped light emitting elements provided on the substrate can be separated in a short time by a simple method.

  Next, referring to FIG. 5, a plurality of first and second light emitting diodes 5 and 6 are arranged between the first electrode 2 and the second electrode 3 formed on the insulating substrate 1. The process will be described.

  First, the insulating substrate 1 having the first electrode 52 and the second electrode 3 to be the first electrode 2 formed on the surface is prepared. The insulating substrate 1 is, for example, a glass substrate, but may be a substrate whose surface is covered with an insulating film. The first and second electrodes 52 and 3 are metal electrodes. As an example, the first and second electrodes 52 and 3 having desired electrode shapes can be formed on the surface of the insulating substrate 1 using a printing technique. Also, a metal film and a photoreceptor film are uniformly laminated on the surface of the insulating substrate 1, and this photoreceptor film is exposed and developed into a desired electrode pattern, and the metal film is etched using the patterned photoreceptor film as a mask. Thus, the first electrode 52 and the second electrode 3 can be formed. FIG. 5 shows only a part of the pair of first and second electrodes 52 and 3 formed on the surface of the insulating substrate 1.

  As the metal material for forming the first and second electrodes 52 and 3, gold, silver, copper, iron, tungsten, tungsten nitride, aluminum, tantalum, and alloys thereof can be used. The insulating substrate 1 is an insulator such as glass, ceramic, alumina, or resin, or a substrate in which a silicon oxide film is formed on a semiconductor surface such as silicon, and the surface is insulative. When a glass substrate is used, it is desirable to form a base insulating film such as a silicon oxide film or a silicon nitride film on the surface.

  Further, it is preferable that the distance between the protruding portion 52A of the first electrode 52 and the protruding portion 3A of the second electrode 3 is slightly shorter than the length of the first and second light emitting diodes 5 and 6. As an example, the distance is preferably 6 to 9 μm when the length of the light emitting diode 7 is 10 μm. That is, the distance is preferably about 60 to 90% of the length of the light emitting diode 7, more preferably 80 to 90% of the length.

  Next, a procedure for arranging the first and second light emitting diodes 5 and 6 on the insulating substrate 1 will be described.

  First, isopropyl alcohol (IPA) as a solution containing a plurality of light emitting diodes 5 and 6 is thinly applied on the insulating substrate 1. The solution containing the plurality of light-emitting diodes 5 and 6 is obtained by immersing the substrate 71 in the IPA solution and vibrating the substrate 71 along the substrate plane with ultrasonic waves in the above-described step of separating the light-emitting diodes. This is obtained by separating a plurality of light emitting diodes from the substrate 71.

  As the above solution, in addition to IPA, ethylene glycol, propylene glycol, methanol, ethanol, acetone, or a mixture thereof may be used, and liquids composed of other organic substances, water, and the like can be used. However, if a large current flows between the first and second electrodes 52 and 3 that are metal electrodes through the liquid, a desired voltage difference cannot be applied between the first and second electrodes 52 and 3. . In such a case, the entire surface of the insulating substrate 1 may be coated with an insulating film of about 10 nm to 30 nm so as to cover the first and second electrodes 52 and 3.

The thickness of the application of the IPA including the plurality of light emitting diodes 5 and 6 is such that the light emitting diodes 5 and 6 can be arranged in the liquid in the next step of arranging the plurality of light emitting diodes 5 and 6. 6 is a movable thickness. Therefore, it is more than the thickness of the light emitting diodes 5 and 6, for example, several micrometers to several mm. If the applied thickness is too thin, the light-emitting diodes 5 and 6 are difficult to move. If it is too thick, the time for drying the liquid becomes long. Preferably, it is 100 micrometers-500 micrometers. Further, the number of light-emitting diodes is preferably 1 × 10 ⁴ / cm ³ to 1 × 10 ⁷ / cm ³ with respect to the amount of IPA.

  In order to apply the IPA including the plurality of light emitting diodes 5 and 6 to the insulating substrate 1, the outer periphery of the first and second electrodes 52 and 3 which are metal electrodes on which the plurality of light emitting diodes 5 and 6 are arranged is arranged. A frame (not shown) may be formed, and IPA including the plurality of light emitting diodes 5 and 6 may be filled in the frame to have a desired thickness. However, when the IPA including the light-emitting diodes 5 and 6 has viscosity, it can be applied to a desired thickness without requiring a frame. The IPA, ethylene glycol, propylene glycol, methanol, ethanol, acetone, or a mixture thereof, or a liquid made of other organic substances, or a liquid such as water has low viscosity for the arrangement process of the light emitting diodes 7. Desirably, it is desirable that it is easily evaporated by heating.

  Next, a potential difference is applied between the first and second electrodes 52 and 3. This potential difference is, for example, a potential difference of 0.5V or 1V. The potential difference between the first electrode 52 and the second electrode 3 can be 0.1 to 10 V. However, if the voltage difference is 0.1 V or less, the arrangement posture of the light-emitting diodes 5 and 6 starts to be disturbed. Then, insulation between metal electrodes begins to become a problem. Therefore, the potential difference is preferably 0.5 V to 5 V, and more preferably about 0.5 V. When the potential VL is applied to the first electrode 52 and the potential VH higher than the potential VL (VL <VH) is applied to the second electrode 3, a negative charge is induced in the first electrode 52, and the second A positive charge is induced on the electrode 3. When the light emitting diodes 5 and 6 approach the first and second electrodes 52 and 3, a positive charge is induced on the side of the light emitting diodes 5 and 6 close to the first electrode 52, and A negative charge is induced on the near side. The charge is induced in the light emitting diodes 5 and 6 by electrostatic induction. Therefore, the light-emitting diodes 5 and 6 have a posture along the electric lines of force generated between the first and second electrodes 52 and 3 and the charges induced in the light-emitting diodes 5 and 6 are substantially equal. Due to the repulsive force due to electric charges, they are regularly arranged in a fixed direction at almost equal intervals. At this time, if the surface of the first and second electrodes 52 and 3 is coated with an insulating film and the potential difference applied between the first and second electrodes 52 and 3 is constant (DC), On the surface of the insulating film coded on the first and second electrodes 52 and 3, ions having the opposite polarity to the potential of the first and second electrodes 52 and 3 are induced, and the electric field in the solution becomes very weak. End up. In such a case, it is preferable to apply an AC voltage between the first and second electrodes 52 and 3. Thereby, it is possible to prevent the ions having the opposite polarities to the potentials of the first and second electrodes 52 and 3 from being induced, and to normally arrange the first and second light emitting diodes 5 and 6. The frequency of the alternating voltage applied between the first and second electrodes 52 and 3 is preferably 10 Hz to 1 MHz, but when the frequency of the alternating voltage is less than 10 Hz, the first and second light emission. The diodes 5 and 6 may vibrate violently and the arrangement may be disturbed. On the other hand, when the frequency of the AC voltage applied between the first and second electrodes 52 and 3 exceeds 1 MHz, the force with which the light-emitting diodes 5 and 6 are attracted to the first and second electrodes 52 and 3 is weak. Therefore, the arrangement may be disturbed by external disturbance. For this reason, in order to stabilize the arrangement of the light emitting diodes 5 and 6, it is more preferable that the frequency of the AC voltage is 50 Hz to 1 kHz. Furthermore, the waveform of the AC voltage is not limited to a sine wave, but may be any waveform that varies periodically, such as a rectangular wave, a triangular wave, and a sawtooth wave. For example, the amplitude of the AC voltage is preferably about 0.5V.

  In this manufacturing process, the external electric field generated between the first and second electrodes 52 and 3 generates charges in the light-emitting diodes 5 and 6, and the first and second electrodes 52 and 3 generate by the attractive force of the charges. Since the light emitting diodes 5 and 6 are adsorbed, the size of the light emitting diodes 5 and 6 needs to be a size that can move in the liquid. Therefore, the allowable value of the size (maximum dimension) of each of the light emitting diodes 5 and 6 varies depending on the application amount (application thickness) of the liquid. When the liquid application amount is small, the size (maximum dimension) of each of the light emitting diodes 5 and 6 must be nanoscale, but when the liquid application amount is large, the size of each light emitting diode 5 and 6 is large. May be in the micron order.

  After a while after the light emitting diodes 5 and 6 are arranged, the light emitting diodes 5 and 6 are arranged between the protruding portion 3A of the second electrode 3 and the protruding portion 52A of the first electrode 52 as shown in FIG. To do. The light emitting diodes 5 and 6 are aligned in a posture perpendicular to the direction in which the first and second electrodes 52 and 3 extend and are arranged at substantially equal intervals in the extending direction. The electric field concentrates between the protruding portion 52A and the protruding portion 3A, and a repulsive force acts between the light emitting diodes 5 and 6 due to charges induced in the light emitting diodes 5 and 6, so that the light emitting diodes 5 and 6 are substantially equal. Line up at intervals.

  Thus, after the first and second light emitting diodes 5 and 6 are arranged between the protrusions 52A and 3A of the first and second electrodes 52 and 3, the substrate 51 is heated or left for a certain period of time. As a result, the liquid of the solution is evaporated and dried, and the light emitting diodes 7 are arranged at equal intervals along the lines of electric force between the metal electrodes 53 and 12 and fixed.

  Next, the electrode 52 is formed on the plurality of first electrodes 2 as shown in FIGS. 6 and 1 by etching, and regions where the red phosphor 11, the green phosphor 12, and the blue phosphor 13 are formed are opened. An insulating film (not shown) is formed, and a through hole (not shown) of the insulating film is formed in a region where the connection portion 7A of the wiring 7 on the first electrode 2 is formed. Then, the wiring 7 is formed by photolithography, and the connection portion 7A of the wiring 7 is electrically connected to the first electrode 2 through the through hole.

  Next, as shown in FIGS. 6 and 1, each of the light emitting diodes 5, 6 is arranged so that the red phosphor 11, the green phosphor 12, and the blue phosphor 13 are sequentially arranged in the second direction X. Any one of the red phosphor 11, the green phosphor 12, and the blue phosphor 13 is coated thereon.

  According to the above manufacturing method, the plurality of light emitting diodes 5 and 6 can be arranged with high controllability and high accuracy between the first electrode 2 and the protruding portion 3A of the second electrode 3. In the above manufacturing method, the plurality of light emitting diodes 5 and 6 include the first light emitting diode 5 and the second light emitting diode 6, and it is difficult to determine the direction (polarity) of each light emitting diode to one. Although the orientation of the first and second light-emitting diodes 5 and 6 is not necessarily in the state shown in FIG. 1, as described above, in the present embodiment, the first and second light-emitting diodes 5 and 6 are 1 is not limited to the arrangement state of FIG. 1, and the light-emitting diodes 5 and 6 may be mixed in a random manner. Therefore, the above manufacturing method manufactures the LED display of the present invention in which the plurality of light emitting diodes composed of the first and second light emitting diodes 5 and 6 are randomly mixed without aligning the direction (polarity) of the plurality of light emitting diodes. It is suitable for. In the above manufacturing method, a large number of fine light-emitting diodes 5 and 6 can be arranged and connected between the electrodes 2 and 3 at a time, so that the size of the light-emitting diodes 5 and 6 is small, for example, 100 μm or less. This is particularly advantageous when the number of light emitting diodes 5 and 6 connected between the first electrode 2 and the second electrode 3 is a large number (for example, 100 or more).

  Therefore, according to the LED display of this embodiment, the number of processes can be reduced while suppressing the occurrence of defects in the light emitting diodes, compared to the conventional example in which it is necessary to repeat the process of transferring a plurality of light emitting diodes between the substrates. It can be reduced and the yield can be improved.

(Second embodiment)
FIG. 10 is an equivalent circuit diagram of an LED display as a second embodiment of the display device of the present invention.

  The second embodiment includes n data line groups DLG1, DLG2,... DLGn shown in FIG. 10 instead of the n data lines DL1, DL2,... DLn shown in FIG. The drive control content by 20 is different from that of the first embodiment. Therefore, in the second embodiment, differences from the first embodiment will be mainly described.

  As shown in FIG. 10, the first data line group DLG1 includes four data lines DL11, DL12, DL13, and DL14.

  The data line DL11 has one end connected to the first, fifth, ninth,..., (1 + 4i) th (i is a natural number of 3 or more) scanning lines SL1, SL5, SL9,..., SL (1 + 4i). , D (1 + 4i) 1 are connected to the other ends of the diodes D11, D51, D91,.

  The data line DL12 has one end on the second, sixth, tenth,..., (2 + 4i) th (i is a natural number of 3 or more) scanning lines SL2, SL6, SL10,..., SL (2 + 4i). .., D (2 + 4i) 1 are connected to the other ends of the connected diodes D21, D61, D101,.

  The data line DL13 has one end on the third, seventh, eleventh,..., (3 + 4i) th (i is a natural number of 3 or more) scanning lines SL3, SL7, SL11,..., SL (3 + 4i). .., D (3 + 4i) 1 are connected to the other ends of the connected diodes D31, D71, D111,.

  The data line DL14 has one end on the fourth, eighth, twelfth,..., (4 + 4i) th (i is a natural number of 3 or more) scanning lines SL4, SL8, SL12,..., SL (4 + 4i). .., D (4 + 4i) 1 are connected to the other ends of the connected diodes D41, D81, D121,.

  The second data line group DLG2 includes four data lines DL21, DL22, DL23, and DL24.

  The data line DL21 has one end connected to the first, fifth, ninth,..., (1 + 4i) th (i is a natural number of 3 or more) scanning lines SL1, SL5, SL9,. , D (1 + 4i) 2 are connected to the other ends of the second row of diodes D12, D52, D92,.

  The data line DL22 has one end on the second, sixth, tenth,..., (2 + 4i) th (i is a natural number of 3 or more) scanning lines SL2, SL6, SL10,..., SL (2 + 4i). .., D (2 + 4i) 2 are connected to the other ends of the connected diodes D22, D62, D102,.

  The data line DL23 has one end on the third, seventh, eleventh,..., (3 + 4i) th (i is a natural number of 3 or more) scanning lines SL3, SL7, SL11,..., SL (3 + 4i). , D (3 + 4i) 2 are connected to the other ends of the connected diodes D32, D72, D112,.

  The data line DL24 has one end on the fourth, eighth, twelfth,..., (4 + 4i) th (i is a natural number of 3 or more) scanning lines SL4, SL8, SL12,..., SL (4 + 4i). , D (4 + 4i) 2 are connected to the other ends of the connected diodes D42, D82, D122,.

  Similarly, the j-th data line group DLGj (j is a natural number of 3 or more) includes four data lines DLDLj1, DLj2, DLj3, and DLj4.

  The data line DLj1 has one end connected to the first, fifth, ninth,..., (1 + 4i) th (i is a natural number of 3 or more) scanning lines SL1, SL5, SL9,..., SL (1 + 4i). , D (1 + 4i) j are connected to the other ends of the diodes D1j, D5j, D9j,.

  The data line DLj2 has one end on the second, sixth, tenth,..., (2 + 4i) th (i is a natural number of 3 or more) scanning lines SL2, SL6, SL10,..., SL (2 + 4i). , D (2 + 4i) j is connected to the other end of the connected diodes D2j, D6j, D10j,.

  The data line DLj3 has one end on the third, seventh, eleventh,..., (3 + 4i) th (i is a natural number of 3 or more) scanning lines SL3, SL7, SL11,..., SL (3 + 4i). .., D (3 + 4i) j is connected to the other end of the connected diodes D3j, D7j, D11j,.

  The data line DLj4 has one end on the fourth, eighth, twelfth,..., (4 + 4i) th (i is a natural number of 3 or more) scanning lines SL4, SL8, SL12,..., SL (4 + 4i). , D (4 + 4i) j is connected to the other end of the connected diodes D4j, D8j, D12j,.

  Next, the contents of control by the row drive circuit 21 and the column drive circuit 22 in the second embodiment will be described.

  First, the first and third drive control at time t = t1 to t4 by the row drive circuit 21 and the column drive circuit 22 will be described.

  The row drive circuit 21 simultaneously applies 0 V to the four scanning lines SL1, SL2, SL3, and SL4 at time t = t1, and sets the other scanning lines SL5 to SLm to Hi-Z (high impedance state). At the same time, the column drive circuit 22 applies 4 V to each data line of the data line groups DLG1 to DLGn to which 0 V has been applied. Here, the column drive circuit 22 controls the time to apply 4 V to each data line of each data line group DLG1 to DLGn according to the data to be displayed (PWM control). When the 4V application time ends, the column drive circuit 22 applies 0V to each data line of the data line groups DLG1 to DLGn to which 4V has been applied.

  Next, at time t = t2, the row driving circuit 21 applies 0 V to the four scanning lines SL2, SL3, SL4, and SL5 simultaneously, and the other scanning lines SL1, SL6 to SLm are set to Hi-Z (high In addition, the column driving circuit 22 applies 4V to each data line of the data line groups DLG1 to DLGn to which 0V has been applied. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t1 for each of the data line groups DLG1 to DLGn.

  Next, at time t = t3, the row driving circuit 21 applies 0V to the four scanning lines SL3 to SL6 simultaneously, and sets the other scanning lines SL1, SL2, and SL7 to SLm to Hi-Z. The column drive circuit 22 applies 4 V to each data line of the data line groups DLG1 to DLGn to which 0 V has been applied. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t1 for each of the data line groups DLG1 to DLGn.

  Next, at time t = t4, the row drive circuit 21 applies 0 V to the four scanning lines SL4 to SL7 simultaneously, and the other scanning lines SL1, SL2, SL3, SL8 to SLm are set to Hi-Z. At the same time, the column drive circuit 22 applies 4 V to each data line of the data line groups DLG1 to DLGn to which 0 V has been applied. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t1 for each data line of each data line group DLG1 to DLGn.

  If the drive control at the time t = t1 is the first drive control, the drive control at the time t = t2 is the third drive control. If the drive control at the time t = t2 is the first drive control, the drive control at the time t = t3 is the third drive control. Similarly, if the drive control at time t = t3 is the first drive control, the drive control at time t = t4 is the third drive control.

  In the control at the time t = t1 described above, among the four rows of light emitting diodes D11 to D4n connected to the four scanning lines SL1 to SL4, the light emitting diodes D11, D12, D14..., Light-emitting diodes D22, D23, D25, D26... Having a cathode K connected to the scanning line SL2, and light-emitting diodes D31, D32, D36. The light emitting diodes D43, D46... To which the cathode K is connected emit light.

  On the other hand, in the control at the time t = t1 described above, among the four rows of light emitting diodes D11 to D4n connected to the four scanning lines SL1 to SL4, the light emitting diodes D13 and D13 having the anode A connected to the scanning line SL1, D15, D16..., Light emitting diodes D21, D24... With anode A connected to scanning line SL2, light emitting diodes D33, D34, D35... With anode A connected to scanning line SL3, and anode A to scanning line SL4. Are not emitted by the light emitting diodes D41, D42, D44, D45.

  Further, in the control at the time t = t2 described above, among the four rows of light emitting diodes D21 to D5n connected to the four scanning lines SL2 to SL5, the light emitting diode D22, whose cathode K is connected to the scanning line SL2, D23, D25, D26..., Light emitting diodes D31, D32, D36... With the cathode K connected to the scanning line SL3, light emitting diodes D43, D46. The light emitting diodes D51, D52, D54, D55... To which the cathode K is connected emit light. A light emitting diode that emits light by the control at the above-described time t = t2 is surrounded by a broken line in FIG.

  On the other hand, in the control at time t = t2 described above, among the four rows of light emitting diodes D21 to D5n connected to the four scanning lines SL2 to SL5, the light emitting diodes D21 and D21 having the anode A connected to the scanning line SL2, D24..., Light emitting diodes D33, D34, D35... With the anode A connected to the scanning line SL3, light emitting diodes D41, D42, D44, D45... With the anode A connected to the scanning line SL4, and the scanning line SL5. The light emitting diodes D53, D56... To which the anode A is connected do not emit light.

  In the control at the time t = t3 described above, among the four rows of light emitting diodes D31 to D6n connected to the four scanning lines SL3 to SL6, the light emitting diode D31, D32, D36..., Light emitting diodes D43, D46... With the cathode K connected to the scanning line SL4, light emitting diodes D51, D52, D54, D55. The light emitting diodes D65 to which the cathode K is connected emit light.

  On the other hand, in the control at the time t = t3 described above, among the four rows of light emitting diodes D31 to D6n connected to the four scanning lines SL3 to SL6, the light emitting diodes D33, D33, which have the anode A connected to the scanning line SL3, D34, D35..., Light emitting diodes D41, D42, D44, D45... With anode A connected to scanning line SL4, light emitting diodes D53, D56... With anode A connected to scanning line SL5, and scanning line SL6. The light emitting diodes D61, D62, D63, D64, D66... To which the anode A is connected do not emit light.

  Further, in the control at time t = t4 described above, among the four rows of light emitting diodes D41 to D7n connected to the four scanning lines SL4 to SL7, the light emitting diodes D43, D43, whose cathode K is connected to the scanning line SL4, D46..., Light emitting diodes D51, D52, D54, D55... With the cathode K connected to the scanning line SL5, light emitting diodes D65 with the cathode K connected to the scanning line SL6, and the cathode K connected to the scanning line SL7. The emitted light emitting diode (not shown) emits light.

  On the other hand, in the control at the above-described time t = t4, among the four rows of light emitting diodes D31 to D7n connected to the four scanning lines SL4 to SL7, the light emitting diodes D41 and D41 having the anode A connected to the scanning line SL4, D42, D44, D45..., Light emitting diodes D53, D56... With the anode A connected to the scanning line SL5, light emitting diodes D61, D62, D63, D64, D66. A light emitting diode (not shown) having the anode A connected to the scanning line SL7 does not emit light.

  As described above, the first light-emitting diode 5 of the four rows of light-emitting diodes connected to the scan lines SL1 to SL4 and the scan line by the first drive control at the time t = t1, t2, t3, and t4. The first light-emitting diode 5 among the four rows of light-emitting diodes connected to SL2 to SL5, the first light-emitting diode 5 of the four rows of light-emitting diodes connected to the scan lines SL3 to SL6, and the scan lines SL4 to SL4. Of the four rows of light emitting diodes connected to SL7, the first light emitting diodes 5 are made to emit light in order.

  Next, the second drive control at time t = t5 to t8 by the row drive circuit 21 and the column drive circuit 22 forming the drive control unit will be described.

  The row drive circuit 21 simultaneously applies 4 V to the four scanning lines SL1, SL2, SL3, and SL4 at time t = t5, and sets the other scanning lines SL5 to SLm to Hi-Z (high impedance state). At the same time, the column drive circuit 22 applies 0V to each data line of the data line groups DLG1 to DLGn to which 4V has been applied. Here, the column drive circuit 22 controls the time for applying 0 V to each data line of each data line group DLG1 to DLGn according to the data to be displayed (PWM control). When the 0V application time ends, the column drive circuit 22 applies 4V to each data line of the data line groups DLG1 to DLGn to which 0V has been applied.

  Next, at time t = t6, the row driving circuit 21 applies 4V to the four scanning lines SL2, SL3, SL4, and SL5 at the same time, and the other scanning lines SL1, SL6 to SLm are set to Hi-Z (high. In addition, the column drive circuit 22 applies 0 V to each data line of the data line groups DLG1 to DLGn to which 4 V has been applied. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t5 for each of the data line groups DLG1 to DLGn.

  Next, at time t = t7, the row driving circuit 21 applies 4V to the four scanning lines SL3 to SL6 at the same time, and sets the other scanning lines SL1, SL2, and SL7 to SLm to Hi-Z. The column drive circuit 22 applies 0V to each data line of the data line groups DLG1 to DLGn to which 4V has been applied. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t5 for each of the data line groups DLG1 to DLGn.

  Next, at time t = t8, the row driving circuit 21 applies 4 V to the four scanning lines SL4 to SL7 simultaneously, and the other scanning lines SL1, SL2, SL3, SL8 to SLm are set to Hi-Z. At the same time, the column drive circuit 22 applies 0V to each data line of the data line groups DLG1 to DLGn to which 4V has been applied. Here, the column drive circuit 22 performs PWM control similar to that described at time t = t5 for each data line of each data line group DLG1 to DLGn.

  If the drive control at the time t = t1 is the first drive control, the drive control at the time t = t5 is the second drive control. If the drive control at time t = t2 is the first drive control, the drive control at time t = t6 is the second drive control. Similarly, when the drive control at time t = t3 is the first drive control, the drive control at time t = t7 is the second drive control.

  In the control at the above-described time t = t5, among the four rows of light emitting diodes D11 to D4n connected to the four scanning lines SL1 to SL4, the light emitting diodes D13, D15, D2 having the anode A connected to the scanning line SL1. D16..., Light emitting diodes D21, D24... With anode A connected to scanning line SL2, .. LED D33, D34, D35... With anode A connected to scanning line SL3, and anode A connected to scanning line SL4. The light emitting diodes D41, D42, D44, D45,.

  On the other hand, in the control at time t = t5 described above, among the four rows of light emitting diodes D11 to D4n connected to the four scanning lines SL1 to SL4, the light emitting diodes D11, D12, D14,..., Light emitting diodes D22, D23, D25, D26... With the cathode K connected to the scanning line SL2, light emitting diodes D31, D32, D36. The light emitting diodes D43, D46... With the cathode K connected to SL4 do not emit light.

  Further, in the control at the time t = t6 described above, among the four rows of light emitting diodes D21 to D5n connected to the four scanning lines SL2 to SL5, the light emitting diode D21, whose anode A is connected to the scanning line SL2, D24..., Light emitting diodes D33, D34, D35... Having the anode A connected to the scanning line SL3, light emitting diodes D41, D42, D44, D45. Light emitting diodes D53, D56,... Connected to the anode A emit light. The light emitting diode that emits light by the control at the time t = t6 described above is surrounded by a broken line in FIG.

  On the other hand, in the control at time t = t6 described above, among the four rows of light emitting diodes D21 to D5n connected to the four scanning lines SL2 to SL5, the light emitting diodes D22, D23, D25, D26..., Light emitting diodes D31, D32, D36... With the cathode K connected to the scanning line SL3, light emitting diodes D43, D46. The light emitting diodes D51, D52, D54, D55... To which the cathode K is connected do not emit light.

  Further, in the control at time t = t7 described above, among the four rows of light emitting diodes D31 to D6n connected to the four scanning lines SL3 to SL6, the light emitting diodes D33, D33, which have the anode A connected to the scanning line SL3, D34, D35..., Light emitting diodes D41, D42, D44, D45... With anode A connected to scanning line SL4, light emitting diodes D53, D56... With anode A connected to scanning line SL5, and scanning line SL6. The light emitting diodes D61, D62, D63, D64, D66... To which the anode A is connected emit light.

  On the other hand, in the control at time t = t7 described above, among the four rows of light emitting diodes D31 to D6n connected to the four scanning lines SL3 to SL6, the light emitting diodes D31, D31, D3, D32, D36..., Light emitting diodes D43, D46... With the cathode K connected to the scanning line SL4, light emitting diodes D51, D52, D54, D55. The light emitting diodes D65 to which the cathode K is connected do not emit light.

  In the control at the time t = t8 described above, among the four rows of light emitting diodes D41 to D7n connected to the four scanning lines SL4 to SL7, the light emitting diodes D41 and D41 having the anode A connected to the scanning line SL4, D42, D44, D45..., Light emitting diodes D53, D56... With the anode A connected to the scanning line SL5, light emitting diodes D61, D62, D63, D64, D66. A light emitting diode (not shown) having the anode A connected to the scanning line SL7 emits light.

  On the other hand, in the control at time t = t8 described above, among the four rows of light emitting diodes D41 to D7n connected to the four scanning lines SL4 to SL7, the light emitting diodes D43, D43, D46..., Light emitting diodes D51, D52, D54, D55... With the cathode K connected to the scanning line SL5, light emitting diodes D65 with the cathode K connected to the scanning line SL6, and the cathode K connected to the scanning line SL7. The light emitting diode (not shown) does not emit light.

  As described above, the second light-emitting diode 6 of the four rows of light-emitting diodes connected to the scan lines SL1 to SL4 and the scan line by the second drive control at the time t = t5, t6, t7, and t8. The second light emitting diodes 6 among the four rows of light emitting diodes connected to SL2 to SL5, the second light emitting diodes 6 of the four rows of light emitting diodes connected to the scanning lines SL3 to SL6, and the scanning lines SL4 to SL4. Of the four rows of light emitting diodes connected to SL7, the second light emitting diodes 6 are made to emit light in order.

  Therefore, in the second embodiment, the first drive control at times t1 to t4 by the row drive circuit 21 and the column drive circuit 22 that form the drive control unit is sequentially connected to the scan lines SL1 to SL4. Four rows of light emitting diodes connected to the scanning lines SL2 to SL5, four rows of light emitting diodes connected to the scanning lines SL3 to SL6, four rows of light emitting diodes connected to the scanning lines SL4 to SL7, For each of the four rows of light emitting diodes, only the first light emitting diode 5 is caused to emit light.

  Subsequently, by the second drive control at time t5 to t8, four rows of light emitting diodes connected to the scanning lines SL1 to SL4, four rows of light emitting diodes connected to the scanning lines SL2 to SL5, and scanning lines in sequence. Only the second light emitting diode 6 emits light for each of the four rows of light emitting diodes, that is, the four rows of light emitting diodes connected to SL3 to SL6 and the four rows of light emitting diodes connected to the scanning lines SL4 to SL7.

  That is, in the second embodiment, the light emitting diodes in four rows in order, and the first light emitting diodes 5 of the light emitting diodes in four rows each shifted from the certain four rows by one row, two rows, and three rows. Are emitted in order from the light emitting diodes of the four rows, and the second light emitting diodes 6 of the light emitting diodes of the four rows shifted by one row, two rows, and three rows from the four rows. Let

  According to the drive control of the light emitting diodes according to the second embodiment, for the light emitting diodes in a certain four rows, the second diodes 6 are caused to emit light after the first diodes 5 are caused to emit light, Compared to the control of causing the second diode 6 to emit light after the first light emitting diode 5 emits light for the next four rows of light emitting diodes shifted by one row, the number of times of switching the energization direction can be reduced and the unit The lighting area per hour can be increased, and the flicker of the image can be reduced.

  Further, according to the second embodiment, since four scanning lines are selected at the same time, image flicker can be reduced as compared with the first embodiment. Further, according to the second embodiment, the area where the light emitting diodes are lit per unit time can be further increased as compared to the first embodiment, and the flicker of the image can be further reduced.

  In the above embodiment, the scanning lines are shifted for each row to emit light. However, for example, the scanning lines may be shifted for every n rows (n is an integer of 2 or more).

  For example, at times t1, t2, t3, and t4, the first light emission of the first line to the fourth line, the third line to the sixth line, the fifth line to the eighth line, and the seventh line to the tenth line, respectively. The diode 5 is caused to emit light, and then at times t5, t6, t7, and t8, the first to fourth lines, the third to sixth lines, the fifth to eighth lines, and the seventh to tenth lines, respectively. The second light emitting diode 6 in the row is caused to emit light.

  Next, at times t9, t10, t11, and t12, the first line of the second line to the fifth line, the fourth line to the seventh line, the sixth line to the ninth line, and the eighth line to the eleventh line, respectively. The light emitting diode 5 is caused to emit light, and then at time t9, t10, t11, t12, the second line to the fifth line, the fourth line to the seventh line, the sixth line to the ninth line, the eighth line to the eleventh line. The second light emitting diode 6 may be controlled to emit light.

  By performing the above control, it is possible to further increase the lighting area per unit time, and to further reduce the flickering of the screen.

  In the first and second embodiments, the light emitting diode having a rod-like structure as shown in FIGS. 3A and 3B is adopted. However, a strip shape produced by the manufacturing process as shown in FIGS. 13A to 13C. A light emitting diode having a structure may be employed. A manufacturing process of the light emitting diode 210 will be described with reference to FIGS. 13A to 13C.

  First, as shown in FIG. 13A, a buffer layer 201 made of AlN or the like, an n-type GaN layer 202, a multiple quantum well (MQW) layer 203, a p-type GaN layer 205, and a transparent electrode 206 are sequentially formed on a sapphire substrate 200. To do.

Next, as shown in FIG. 13B, only the transparent electrode 206, the p-type GaN layer 205, and the multiple quantum well (MQW) layer 203 at one end of the strip-like pattern are etched by photolithography and etching. Then, the n-type GaN layer 202 is exposed. Thereafter, an insulating film 207 made of SiO ₂ or the like is formed, and the sapphire substrate 200 and the buffer layer 201 are removed. For example, this removal is performed by polishing, wet etching, or the like. Next, a plurality of strip-shaped light emitting diodes 210 are formed by etching or physical cutting.

  The plurality of strip-shaped light emitting diodes 210 can be arranged between the first and second electrodes of the insulating substrate, for example, in the same manner as described with reference to FIG. 5 in the first embodiment. In this case, it is assumed that an insulating film is formed on the first and second electrodes. In FIG. 13B and FIG. 13C, illustration of the insulating substrate and the first and second electrodes is omitted.

  Next, as shown in FIG. 13C, after arranging the strip-shaped light emitting diodes 210, an extraction electrode 212 is formed on the n-type GaN layer 202 at one end in the longitudinal direction of the light emitting diodes 210 by photolithography. A lead electrode 213 is formed on the transparent electrode 206 at one end in the longitudinal direction of the light emitting diode 210. The extraction electrodes 212 and 213 are electrically connected to the first and second electrodes.

  Moreover, in the said embodiment, as demonstrated with reference to FIG. 4A-FIG. 4E, although the crystal | crystallization was grown from the board | substrate 71 and the rod-shaped semiconductor core 73 was formed, the semiconductor layer formed on the board | substrate was etched and rod-shaped. The semiconductor core may be formed, and a semiconductor layer covering the semiconductor core may be formed. Moreover, in the said embodiment, it is preferable that the maximum dimension of the said light emitting diode is 100 micrometers or less. When the maximum dimension of the light emitting diode is 100 μm or less, it is suitable for the present invention where the direction of the light emitting diode may be random. In addition, since the size of the light emitting diode is small, heat does not spread to the light emitting region, and it is possible to prevent a decrease in output and a life due to heat.

  In the first embodiment, the first to third drive control is performed on the four rows of light emitting diodes connected to the four scanning lines SL1 to SL4, and then the four scanning lines SL5 to SL8 are performed. The first to third drive control is performed for the four rows of light emitting diodes connected to the first row, but the first to third drives are performed for the three rows of light emitting diodes connected to the three scanning lines SL1 to SL3. Then, the first to third drive control may be performed on the three rows of light emitting diodes connected to the three scanning lines SL4 to SL6. Further, the first to third drive control is performed for the two rows of light emitting diodes connected to the two scanning lines SL1 and SL2, and then the two rows of light emitting diodes connected to the two scanning lines SL3 and SL4 are performed. You may perform 1st-3rd drive control about a light emitting diode. Further, first to third drive control is performed for five or more rows of light emitting diodes connected to five or more scanning lines, and then five or more scanning lines next to the five or more scanning lines are performed. The first to third drive control may be performed on the light emitting diodes connected to the five or more rows.

  In the second embodiment, the first, second, and third drive control is performed by using four rows of light emitting diodes adjacent in the first direction as a unit, but two rows adjacent in the first direction. Alternatively, the first, second, and third drive control may be performed with light emitting diodes in three rows or five rows or more as one unit.

DESCRIPTION OF SYMBOLS 1 Insulating board | substrate 2,52 1st electrode 3 2nd electrode 3A Protrusion part 5 1st light emitting diode 6 2nd light emitting diode 7 Wiring 7A Connection part 11 Red fluorescent substance 12 Green fluorescent substance 13 Blue fluorescent substance 21 line Drive circuit 22 Column drive circuit 31 Core part 32 Outer peripheral surface 33 Shell part 35 Bonding surface 71 Substrate 72 Mask 72a Growth hole 73 Semiconductor core 74 Semiconductor layer 200 SOI substrate 201 Silicon substrate 202 BOX layer 203 SOI layer 205 n-type impurity region 206 p Type impurity region 207 trench 210 plate-like light emitting diode A anode K cathode DL1 to DLn data line DLG1 to DLGn data line group SL1 to SLm scanning line

Claims (6)

A substrate,
A first electrode formed on the substrate;
A second electrode formed on the substrate;
A plurality of plate-shaped or bar-shaped light emitting diodes electrically connected between the first electrode and the second electrode;
The plurality of light emitting diodes are:
A first light emitting diode having an anode electrically connected to the first electrode and a cathode electrically connected to the second electrode;
A second light emitting diode having a cathode electrically connected to the first electrode and an anode electrically connected to the second electrode;
The first light emitting diode and the second light emitting diode are randomly arranged between the first electrode and the second electrode on the substrate without matching the polarity,
The plurality of light emitting diodes are arranged in a matrix on the substrate,
The first electrode is
Of the plurality of light emitting diodes arranged in a matrix, electrically connected to the anodes or cathodes of the plurality of light emitting diodes arranged in the first direction,
The second electrode is
Of the plurality of light emitting diodes arranged in a matrix, electrically connected to the anodes or cathodes of the plurality of light emitting diodes arranged in a second direction intersecting the first direction,
And a drive controller that is electrically connected to the first electrode and the second electrode and drives the first and second light emitting diodes,
The drive control unit
The light emitting diodes in a row composed of a plurality of light emitting diodes arranged in the second direction or a plurality of rows of light emitting diodes adjacent in the first direction so that only the first light emitting diodes emit light. A first drive control for passing a current through the first and second electrodes;
The light emitting diodes in a row composed of a plurality of light emitting diodes arranged in the second direction or the light emitting diodes in a plurality of rows adjacent in the first direction so that only the second light emitting diodes emit light. A second drive control for passing a current through the first and second electrodes;
Between the first drive control and the second drive control, one row of light emitting diodes adjacent to the one row of light emitting diodes arranged in the second direction or one row from the plurality of rows of light emitting diodes. 3. A display device comprising: a third drive control for causing a current to flow through the first and second electrodes so that only the first light-emitting diodes emit light among a plurality of shifted light-emitting diodes. A substrate,
A first electrode formed on the substrate;
A second electrode formed on the substrate;
A plurality of plate-shaped or bar-shaped light emitting diodes electrically connected between the first electrode and the second electrode;
The plurality of light emitting diodes are:
A first light emitting diode having an anode electrically connected to the first electrode and a cathode electrically connected to the second electrode;
A second light emitting diode having a cathode electrically connected to the first electrode and an anode electrically connected to the second electrode;
The first light emitting diode and the second light emitting diode are randomly arranged between the first electrode and the second electrode on the substrate without matching the polarity,
The plurality of light emitting diodes are arranged in a matrix on the substrate,
The first electrode is
Of the plurality of light emitting diodes arranged in a matrix, electrically connected to the anodes or cathodes of the plurality of light emitting diodes arranged in the first direction,
The second electrode is
Of the plurality of light emitting diodes arranged in a matrix, electrically connected to the anodes or cathodes of the plurality of light emitting diodes arranged in a second direction intersecting the first direction,
And a drive controller that is electrically connected to the first electrode and the second electrode and drives the first and second light emitting diodes,
The drive control unit
The light emitting diodes in a row composed of a plurality of light emitting diodes arranged in the second direction or a plurality of rows of light emitting diodes adjacent in the first direction so that only the first light emitting diodes emit light. A first drive control for passing a current through the first and second electrodes;
The light emitting diodes in a row composed of a plurality of light emitting diodes arranged in the second direction or the light emitting diodes in a plurality of rows adjacent in the first direction so that only the second light emitting diodes emit light. A second drive control for passing a current through the first and second electrodes;
One row of light emitting diodes shifted by n rows (n is an integer of 2 or more) from the one row of light emitting diodes arranged in the second direction between the first drive control and the second drive control Alternatively, a third drive control that allows current to flow through the first and second electrodes so that only the first light emitting diode among the plurality of rows of light emitting diodes shifted by n rows from the plurality of rows of light emitting diodes is caused to emit light. And a display device. The display device according to claim 2,
The drive control unit
Further, among the one row of light emitting diodes emitted by the third drive control after the second drive control, or the plurality of rows of light emitting diodes emitted by the third drive control, the second light emitting diode. 4th drive control which sends an electric current through the said 1st, 2nd electrode so that only light may be emitted,
Thereafter, light emission in a plurality of rows shifted by one row from the light emitting diodes in the row adjacent to the light emitting diodes in the row driven by the fourth driving control or the light emitting diodes in the rows driven by the fourth driving control. A display device characterized by performing a fifth drive control for passing a current through the first and second electrodes so that only the first light emitting diode among the diodes emits light. The display device according to any one of claims 1 to 3,
The light emitting diode is
A core portion of a first conductivity type;
A second conductive type shell portion covering the outer peripheral surface of the first conductive type core portion,
A part of the outer peripheral surface of the first conductivity type core portion is exposed from the second conductivity type shell portion. The display device according to any one of claims 1 to 4,
The maximum size of the light emitting diode is 100 μm or less. The display device according to any one of claims 1 to 5,
A display device, wherein the minimum dimension of the light emitting diode is 500 nm or more.

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