JP2006054312A - Light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element in which the emission control of polychromatic light and white light can be carried out by a simple drive system by eliminating the complexity of color control in a multi-chip system light emitting element and the complexity of circuitry. <P>SOLUTION: In the light emitting element 1A integrating a plurality of light emitting diodes 2R, 2G and 2B and an IC 3 for driving these light emitting diodes, the driving IC 3 comprises a counter 12, a signal control circuit 13 and a multi-bit driver 15. The light emitting element 1A capable of emitting light of an arbitrary color of white and from red to blue with a small number of terminals can be obtained by emitting light from the plurality of light emitting diodes 2R, 2G and 2B in the light emitting element 1A sequentially and selectively with control signals CRGB inputted from an external terminal 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a lamp-type or chip-type light-emitting element that is integrally provided with a plurality of light-emitting diodes and their driving ICs, and is particularly provided with a plurality of light-emitting diodes and their driving ICs that are integrally provided with red (R), The present invention relates to a light emitting element including three primary colors of green (G) and blue (B) and capable of emitting any color as well as white light.

  Conventionally, Patent Document 1 discloses a light-emitting element that can emit pseudo white light by combining a light-emitting diode and a phosphor that emits light of a color complementary to the light-emitting diode. In this case, generally, a light emitting diode that emits blue light is used, and a phosphor that absorbs blue light and emits yellow light is combined so that the human eye can feel white light in a pseudo manner. Is frequently used. However, such a combination has a problem that the color rendering property is lacking because there are few specific color components, that is, in the case of the above-described mixed color of blue and yellow, the red component is small.

  As another method of emitting white light, an example using a mixed color of three primary colors using light emitting diodes that emit RGB light is also known. However, when white light is emitted by mixing the three primary colors, for example, as is apparent from the light emission intensity-forward current characteristics of various typical light emitting diodes shown in FIG. 11, the electro-optics of the light emitting diodes that emit RGB light. Since there is a large difference in characteristics, current adjustment for adjusting the light emission degree of each color becomes very troublesome.

  Even in cases other than white light emission, if it is necessary to obtain a desired color or light emission intensity distribution using a plurality of light emitting diodes of RGB or different colors, the light emission intensity of each light emitting diode can be reduced. It is necessary to adjust, but current adjustment for that purpose becomes troublesome. Further, this current adjustment can be adjusted by an external circuit, but it is necessary to provide an external circuit for each light emitting element, and there is a problem that the circuit configuration becomes complicated.

  Conventionally, a so-called multi-chip type light emitting device in which the light emitting diodes of the three primary colors of R, G, and B are integrated has seven colors or many by controlling the value of current flowing through each of the light emitting diodes of R, G, and B. Although color control is performed, since it is necessary to provide separate wiring for each other than the cathode terminal or the anode terminal, at least four external terminals are required, and a current capacity of about several tens of mA is secured. Wiring needs to be applied. In addition, white light obtained when all three primary colors R, G, and B are turned on has a design current value (for example, R: Even when set to 10 mA, G: 7 mA, B: 10 mA, etc., there is a variation in chromaticity depending on the product due to variations in electro-optical characteristics of individual light emitting diodes.

Further, as shown in the spectral distribution characteristic diagram of various light emitting diodes of white light using a mixed color of three primary colors using light emitting diodes that emit RGB light, the interval between the emission spectra of R and G is G Therefore, there is a region where the emission spectrum distribution is discontinuous between R and G. Therefore, in order to obtain white light with higher color rendering properties, not only the light emitting diodes of the three primary colors R, G, and B, but also the orange (O) and yellow (Y) light emission spectrum distribution located between R and G At least one of the light-emitting diodes is further used. However, since the number of terminals of the light-emitting element in which these light-emitting diodes are made into a multichip further increases, the above-described problem appears more greatly.
JP 2001-217463 A

  The present invention has been made to solve the above-mentioned problems of the prior art, and its object is to eliminate the complexity of color control and circuit configuration in a multi-chip light emitting element, and to simplify the process. An object of the present invention is to provide a light emitting element capable of controlling light emission of multicolor light and white light by a simple driving method.

  Another object of the present invention is that, in a multi-chip type light emitting device, for example, at least four external terminals are required to perform light emission control of three primary colors of red, green, and blue. Provided is a light-emitting element that can be controlled by a small number of external terminals such as three terminals and that can control light emission of a complex color with a small number of external terminals.

  Still another object of the present invention is to provide a light emitting device having a configuration capable of easily and accurately controlling variations in white chromaticity obtained from each of the R, G, and B primary light emitting diodes.

  Furthermore, another object of the present invention is to provide a discontinuous emission spectrum distribution in a multi-chip type light emitting device, because white light emission by three primary colors of red, green and blue has a wide interval between red and green emission spectra. An object is to provide a light-emitting element which has a region and is incomplete as white light, but can easily obtain white light having a continuous spectral distribution from red to blue.

  Each of the above objects of the present invention can be achieved by the following configurations. That is, the invention of the light emitting device according to claim 1 is a light emitting device in which a plurality of light emitting diodes and a driving IC for driving these light emitting diodes are integrated, and the driving IC includes a current supply circuit, a counter And a signal control circuit and a plurality of bit drivers. In this case, a combination of arbitrary colors can be used as the plurality of light emitting diodes. However, it is preferable to use a combination capable of obtaining white light because the use is widened.

  According to a second aspect of the present invention, in the light emitting device according to the first aspect, the plurality of bit drivers control a current value for each of the plurality of light emitting diodes or a current ratio between the plurality of light emitting diodes to be constant. It is characterized by being.

  The invention according to claim 3 is the light emitting device according to claim 1, wherein the plurality of bit drivers finely adjust a current value for each of the plurality of light emitting diodes or a current ratio between the plurality of light emitting diodes. It is characterized by having.

  According to a fourth aspect of the present invention, in the light emitting device according to the third aspect, the fine adjustment is performed based on correction data stored in a nonvolatile memory built in the driving IC. Features.

  According to a fifth aspect of the present invention, in the light emitting device according to the first or second aspect, the counter circuit of the driving IC sequentially switches light emission for each of the plurality of light emitting diodes by at least one external signal terminal. It is characterized by having a configuration. In this case, the counter circuit can be appropriately selected and used according to the number of light emitting diodes, but 3 bits or more are preferable for emitting white light.

  According to a sixth aspect of the present invention, in the light emitting device according to the first aspect, the plurality of light emitting diodes have a light emitting color capable of emitting white light by a color mixture of the light.

  According to a seventh aspect of the present invention, in the light emitting device according to the sixth aspect of the present invention, the plurality of light emitting diodes include those that emit light of three primary colors of red, green, and blue.

  The invention according to claim 8 is the light-emitting device according to claim 7, wherein the plurality of light-emitting diodes further include a light-emitting light having a center wavelength between red and green. To do.

  According to a ninth aspect of the present invention, in the light emitting device according to the seventh aspect, the plurality of light emitting diodes further include a light emitting element that emits at least one of orange and yellow.

  The invention according to claim 10 is the light emitting device according to any one of claims 1 to 9, wherein the plurality of light emitting diodes are provided on a surface of the driving IC.

  The invention according to claim 11 is the light emitting device according to any one of claims 1 to 10, wherein the plurality of light emitting diodes and the driving IC are covered with the same resin. .

  By providing the above configuration, the present invention has the following excellent effects. That is, according to the first aspect of the present invention, since the driving IC for controlling the plurality of light emitting diodes is integrated with the plurality of light emitting diodes, the number of terminals to be connected to the outside is reduced and the driving IC is used. Since the current value supplied to each light emitting diode can be controlled, a light emitting element with high chromaticity accuracy can be easily obtained without performing complicated current control outside the light emitting element.

  According to the invention of claim 2, since the current supplied to each of the plurality of light emitting diodes can be controlled to a constant value, the light emission intensity of the selected light emitting diode can be maintained at a constant value. Since the current ratio between the light emitting diodes can be controlled to be constant, the chromaticity of the synthesized light can be kept constant.

  According to the invention of claim 3, the variation in electro-optical characteristics between the light emitting diodes of the same color for each light emitting element can be corrected, and the current flowing through each light emitting diode for obtaining light of a predetermined synthesized color Since the value can be controlled, it is possible to obtain a light emitting element of uniform quality that can easily and accurately control the variation in light emission intensity and light emission color for each light emitting element.

  Further, according to the invention of claim 4, since the data for correcting the emission intensity and the variation in emission color for each light emitting element can be stored and used in the nonvolatile memory built in the driving IC, the user can use the data for each light emitting element. Therefore, a light-emitting element that can simplify the external circuit configuration at the time of use can be obtained.

  According to the invention of claim 5, by using the counter, a light emitting element capable of appropriately switching light emission of a plurality of light emitting diodes by one external signal is obtained.

  The white light source is a light source required in a wide technical field such as a backlight of a liquid crystal display panel, illumination light, and the like. According to the invention of claim 6, a light-emitting element that can be applied to these wide technical fields Is obtained.

  According to the invention of claim 7, a light emitting element capable of easily emitting white light having high color rendering properties can be obtained.

  According to the eighth and ninth aspects of the present invention, the colored light having a center wavelength between red and green is emitted between the emission spectrum of the red light emitting diode and the emission spectrum of the green light emitting diode having a wide emission spectrum interval. Since it can be supplemented by at least one of a light emitting diode or an orange light emitting diode and a yellow light emitting diode, a light emitting element capable of obtaining white light having a substantially continuous spectral distribution from red to blue can be obtained.

  Further, according to the invention of claim 10, since the driving IC itself can be used as a substrate for fixing a plurality of light emitting diodes, a small light emitting element can be obtained.

  According to the eleventh aspect of the present invention, since the plurality of light emitting diodes and the driving IC are covered and integrated with the same resin, a light emitting element with good assembling workability can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below describes an example of a light emitting element including light emitting diodes of three primary colors of RGB for embodying the technical idea of the present invention.

  However, the present invention includes a plurality of light emitting diodes capable of emitting other colors even in the case of a light emitting element combined with a light emitting diode capable of emitting at least one of orange and yellow other than the three primary colors of RGB. The present invention is equally applicable to light emitting elements. In general, the spectral distribution characteristics of the RGB light emitting diodes are such that the peak wavelength of the green light emitting diodes is greatly biased toward the blue light emitting diode side than the midpoint of the peak wavelengths of the blue and red light emitting diodes. There is a discontinuous wavelength region between the green and red light emitting diodes, but by adding an orange or yellow light emitting diode with a peak wavelength between the red and green light emitting diodes, Discontinuous regions can be filled, and color rendering can be further enhanced.

  A light-emitting element 1A of Example 1 will be described with reference to FIGS. 1 is an external perspective view of the light emitting element 1A of Example 1 seen through the mold resin, and FIG. 2 is an equivalent circuit diagram showing the driving IC of the light emitting element 1A of FIG. 1 in a block diagram. FIG. 3 is a diagram showing a specific example of the internal circuit of the driving IC used in the first embodiment, and FIG. 4 is a timing chart for explaining the operation of the driving IC of the first embodiment.

  The light emitting element 1A is configured by integrating a plurality of light emitting diodes 2 in a chip state on a driving IC 3 which also serves as a circuit board for driving these light emitting diodes, in order to make a small light emitting element. Each light emitting diode 2 is constituted by a bare chip that is divided from the wafer, and has a cathode electrode on the back surface. In the first embodiment, in order to emit white light, three light emitting diodes 2R and 2G having light emission colors of three primary colors, red (R), green (G), and blue (B), as a plurality of light emitting diodes 2. 2B was used.

  The driving IC 3 includes output terminals 3R, 3G, and 3B corresponding to the light emitting diodes 2R, 2G, and 2B on the surface, and the current value for each light emitting diode 2R, 2G, and 2B or between the light emitting diodes 2R, 2G, and 2B. It incorporates a drive circuit for controlling the current ratio at a constant. By this drive circuit, the output current of each output terminal is adjusted, and the light emission intensity of each light emitting diode 2R, 2G, 2B is maintained within a preset range.

  This driving IC 3 mixes the light emission colors of the three light emitting diodes 2R, 2G, and 2B, so that when each driving pulse width is the same, white is obtained, and the current value or current of each output is obtained. The ratio is preset.

  The light emitting element 1 </ b> A is at least a three-terminal light emitting element, and includes three external terminals 5 to 7. The driving IC 3 that also functions as a circuit board includes an external terminal 5 that functions as one power supply terminal and an external terminal 6 that functions as the other power supply terminal, which are electrically insulated from each other on the lower surface and side surfaces of the driving IC 3. A part of the light emitting diodes 2R, 2G, and 2B is fixedly disposed on the surface of the external terminal 6 using a conductive material. The driving IC 3 is further provided with an external terminal 7 for inputting a control signal CRGB and a plurality of terminals such as output terminals 3R, 3G, 3B for the light emitting diodes 2R, 2G, 2B on the surface, and among these, an output terminal The light emitting diodes 2R, 2G, and 2B and the light emitting diodes 2R, 2G, and 2B are electrically connected by a wire such as a gold wire.

  Since the plurality of light emitting diodes 2R, 2G, and 2B used in the first embodiment are those having a cathode electrode on the back surface, they are fixed to the external terminal 6 by a conductive material, but the plurality of light emitting diodes 2R are used. When 2G and 2B are provided with both anode and cathode electrodes on the surface, it is necessary to wire these electrodes with wires.

  In the light emitting element 1A of the first embodiment, these light emitting diodes 2R, 2G, and 2B are fixed to the surface of the driving IC, and after wiring, the surfaces are covered with a light-transmitting mold resin 9. It is produced by this.

  As shown in FIG. 2, the light emitting element 1A connects a driving IC 3 and a light emitting circuit including light emitting diodes 2R, 2G, and 2B connected to the driving IC 3 between two external terminals 5 and 6, and The circuit configuration is such that the control signal CRGB is input. When the light emitting diodes 2R, 2G, and 2B are integrated without providing the driving IC 3 as in the conventional example, a minimum of four terminals are required, but in the first embodiment, only three terminals are required. Note that a separate reset SET terminal may be provided to form a four-terminal light-emitting element.

Next, a specific example of the driving IC 3 used in the first embodiment will be described with reference to FIGS. The driving IC 3 includes a current supply circuit 11, a 3-bit counter 12, various signal control circuits 13, and a 3-bit driver 15. The 3-bit counter circuit 12 selects one of the _three output terminals 12 _{1 to} 12 ₃ in order in synchronization with the rising edge of the pulse input as the control signal CRGB, and outputs to each of the output terminals 1 to 3. One of the corresponding light emitting diodes 2R, 2G, and 2B is caused to emit light by supplying a predetermined drive current from the current supply circuit 11 through various signal control circuits 13 and a 3-bit driver 15. Yes.

  The various signal control circuits 13 send the output signal from the counter circuit 12 to the 3-bit driver 15 via the waveform shaping circuits 13R, 13G, and 13B in which two inverting circuits are connected in series. The 3-bit driver 15 is a reference current supply circuit formed of a CMOS circuit and an FET as indicated by reference numerals 15R, 15G, and 15B in FIG. 3. Here, a current supplied from a power supply VDD2 is supplied to each light emitting diode 2R, 2G and 2B are supplied. The power supply VDD2 may be directly connected to one external terminal 5 which is a power supply terminal or connected via a predetermined constant voltage circuit (not shown). The current flowing from the 3-bit driver 15 to each of the light emitting diodes 2R, 2G, 2B can be changed by changing the circuit constants of the drivers 15R, 15G, 15B or by changing the voltage of the constant voltage circuit. When the drive pulse widths of 2R, 2G, and 2B are the same, the white color is adjusted.

The operation of this driving IC 3 is as shown in the timing chart of FIG. That is, when a power supply voltage is supplied to the driving IC 3 and a pulse-like control signal CRGB is input to the external terminal 7, the output terminals 12 ₁ to 12 of the 3-bit counter circuit 12 are synchronized with the rise of the pulse. 12 one output terminal appears among the _three, the output of the terminal in synchronization with the falling of the pulse is lost. When the next pulse is input to the external terminal 7, an output appears at the next terminal different from the output terminal selected first. In other words, 3-bit counter circuit 12, each time a pulse is inputted to the external terminal 7, it is selected one of the output terminals ₁₂ 1 to 12 _3, the light emitting diode 2R corresponding to the output terminal ₁₂ 1 to 12 ₃ When any one of 2G and 2B emits light and none of the output terminals 12 _{1 to} 12 ₃ is selected, none of the light emitting diodes 2R, 2G and 2B emits light.

  Therefore, in the light emitting element 1A of the first embodiment, three pulses form one cycle, and the light emitting diodes 2R, 2G, and 2B emit light in order during the one cycle. Therefore, as shown in FIG. 4, when the widths of three consecutive pulses in one cycle are all equal as the control signal CRGB (for example, in the case of the region a), each of the light emitting diodes 2R, 2G, 2B Since the light emission times are equal, if the light emission interval is determined in consideration of the afterimage time of the human eye, the emission color visible to the human eye is white. When the widths of three consecutive pulses are different as the control signal CRGB (for example, in the case of the region b), the light emission times of the light-emitting diodes 2R, 2G, and 2B are the pulse widths of the corresponding control signal CRGB. Therefore, the luminescent color visible to the human eye is a color in which a color having a long luminescent time is emphasized.

In this case, when the pulse control signal CRGB is input to the input terminal 7, the 3-bit counter 12 sequentially provides outputs to the output terminals 12 _{1 to} 12 ₃ , so that each of the light emitting diodes 2 R, 2 G, and 2 B The light is emitted in a predetermined order. Therefore, for example, when it is desired to obtain red light, the pulse width corresponding to the red light emitting diode 2R in the control signal CRGB is maximized in one cycle, and the pulse widths corresponding to the green light emitting diode 2G and the blue light emitting diode 2B are 3-bit counters. What is necessary is just to make it the smallest within the range which 12 can respond. In the light emitting element 1A of the first embodiment, a SET terminal for resetting the 3-bit counter 12 may be provided as necessary.

  In this way, by changing the width of each of the three consecutive pulses as the control signal CRGB according to the required emission color, it is possible to develop a substantially stepless color from red to blue, In the case of white light, white light having red, green, and blue light-emitting components and high chromaticity accuracy can be obtained.

  In the light emitting element 1A of the first embodiment, the current flowing from the 3-bit driver 15 to each of the light emitting diodes 2R, 2G, 2B and the current value flowing to each of the light emitting diodes 2R, 2G, 2B are represented as light emission intensity-forward current characteristics. In addition, in order to correct variations in electro-optical characteristics of individual light emitting diodes, each light emitting diode 2R can be obtained by changing the circuit constants of the respective drivers 15R, 15G, 15B or by changing the voltage of the constant voltage circuit. Although the adjustment is performed so that white is obtained when the drive pulse widths of 2G and 2B are the same, such an adjustment method is a method that can be performed during the assembly of the light emitting element 1A, Adjustment is difficult after the assembly of the element 1A.

  Therefore, as Example 2, the current value flowing to each light emitting diode 2R, 2G, 2B can be adjusted from the outside, and the difference in optical characteristics between the respective light emitting diodes 2R, 2G, 2B is corrected after the light emitting element is assembled. A light-emitting element 1B that can be manufactured was manufactured.

  The light emitting element 1B will be described with reference to FIGS. Here, FIG. 5 is an equivalent circuit diagram showing the driving IC of the light emitting element 1B of the second embodiment in a block diagram, and FIG. 6 shows a specific example of the internal circuit of the control IC used in the second embodiment. FIG.

  5 and 6, the same reference numerals are given to the same components as those of the light emitting element 1 </ b> A of Example 1, and a part of the description will be omitted.

  In the light emitting element 1B of the second embodiment, a driving IC 3 ′ and a light emitting circuit composed of a plurality of light emitting diodes 2R, 2G, and 2B connected to the driving IC 3 ′ are connected between two external terminals 5 and 6, and Although the circuit configuration in which the control signal CRGB is input to the input terminal 7 is the same as that of the light emitting element 1A of the first embodiment, the configuration of the driving IC 3 ′ is the internal configuration of the driving IC 3 of the first embodiment. Is different.

  That is, the driving IC 3 ′ of the second embodiment includes a current supply circuit 11, a 3-bit counter 12, a 3 × 3-bit nonvolatile memory 17, various signal control circuits 18 and a driver 19 as shown in FIGS. Among them, the 3 × 3 bit nonvolatile memory 17 stores 3 bits for each bit, that is, 8 levels of correction levels, and outputs of the selected correction level are various signal control circuits 18 and drivers 19. Then, a predetermined corrected current is supplied to each of the light emitting diodes 2R, 2G, and 2B.

The various signal control circuits 18 include three signal control circuit blocks 18R, 18G, and 18B corresponding to the respective light emitting diodes 2R, 2G, and 2B. Each signal control circuit block 18R, 18G, and 18B is, for example, green. of taking an example those of the light emitting diode 2G drive, two inverting circuit and the waveform shaping circuit 18G ₁ connected in series, 3 × 3 bit output and an output terminal 12 ₂ of the output of the counter circuit 12 from the nonvolatile memory 17 The output of each signal control circuit block 18G is input to the corresponding drivers 19G1 to 19G4 of the 3 × 4 bit driver 19G, and each of the drivers 19G1 to 19G4 The output is connected in parallel and supplied to the corresponding green light emitting diode 2G. That.

  The signal control circuit blocks 18R and 18B for driving the red light emitting diode 2R and the blue light emitting diode 2B and the 3 × 4 bit drivers 19R and 19B are also signal control circuit blocks 18G and 3 × for driving the green light emitting diode 2G. Although the configuration is the same as that of the 4-bit driver 19G, the illustration is omitted.

  The light emission color of the light emitting element 1B of Example 2 is adjusted by the following method. First, an average current value TYP for obtaining white light is obtained from the light emission intensity-forward current characteristics of each of the plurality of light-emitting diodes 2R, 2G, and 2B. In consideration of the current value, for example, every 5%, eight levels of current values of + 20%, + 15%, + 10%, + 5%, TYP, −5%, −10%, and −15% are determined. .

Then, 3 × 4-bit driver 19G is a current value corresponding to the -15% as the output current of the driver 19G1 driven only by terminals 12 ₂ of the output of the counter circuit 12 so as to supply the other three drivers Each of 19G2 to 19G4 supplies a current corresponding to + 5%, + 10%, and + 20% corresponding to the predetermined current interval.

Then, the light emitting diode 2G, the output to the terminal 12 ₂ of the counter circuit 12 appears, always with the current corresponding to the -15% of the from the driver 19G1 supplied, stored in the 3 × 3-bit nonvolatile memory 17 Since the output currents from the other three drivers 19G2 to 19G4 are simultaneously supplied according to the output based on the data, the current value supplied to the light emitting diode 2G is -10%, with -15% being the lowest value,- It can be changed to 8 levels of 5%, TYP, + 5%, + 10%, + 15% and + 20%.

  By adopting such a configuration, a predetermined correction is applied to the 3 × 3 bit nonvolatile memory 17 so that a predetermined corrected current can be supplied to the light emitting diode 2G during or after the assembly of the light emitting element 1B. If the data is stored, a predetermined corrected current value can be supplied to the light emitting diode 2G.

  Here, the case where the green light emitting diode 2R is caused to emit light has been described as an example. However, the same applies to the case where the red light emitting diode 2R and the blue light emitting diode 2B are caused to emit light. By supplying current values corrected for all of 2R, 2G, and 2B, a light-emitting element having a desired chromaticity can be obtained. The operation of the drive circuit 3 ′ of the light emitting element 1B of the second embodiment is also as shown in FIG. 5 which is a timing chart of the drive circuit 3 of the light emitting element 1A of the first embodiment. Omitted.

  The light-emitting element 1A of the first embodiment is an example in which a plurality of light-emitting diodes 2R, 2G, and 2B in a chip state are integrated on a driving IC 3 that also serves as a circuit board in order to make a small light-emitting element. In Example 3, light emitting elements 1C and 1D in which a driving IC and a plurality of light emitting diodes 2R, 2G, and 2B were mounted on a substrate having a lead frame were manufactured.

  The light-emitting elements 1C and 1D of Example 3 will be described with reference to FIGS. 7 is a plan view showing the light-transmitting mold resin of the light-emitting element 1C of Example 3 that is transmitted through. FIG. 8 is a plan view showing the light-transmitting property of the light-emitting element 1D of another aspect of Example 3. FIG. It is the top view which permeate | transmitted and expressed mold resin, The same referential mark is provided to the same component as 1 A of light emitting elements of Example 1, and suppose that a one part description is abbreviate | omitted.

  The light-emitting element 1C of Example 3 is greatly different from the light-emitting element 1A of Example 1 in that a mold type having a 4-terminal lead frame is used as the substrate 4, and the other two of them are used. The cathode electrode side of each light emitting diode 2R, 2G, 2B is fixedly arranged using a conductive material on a wide lead frame 8 connecting the external terminals 6, 6, and the driving IC 3 is placed on the mold portion. In addition, in the light emitting element 1D of another aspect, not only the light emitting diodes 2R, 2G, and 2B but also the driving IC 3 is placed on the frame 8 to improve the heat radiation efficiency and to set the reset terminal SET. The configuration is largely different from the light emitting device 1A of Example 1 in that it is provided.

  Further, terminals such as output terminals 3R, 3G, and 3B, a control signal input terminal 3C, a power supply voltage input terminal 3V, and a common terminal 3E for each light emitting diode are arranged on the surface of the driving IC 3 used in the third embodiment. Among these, between the output terminals 3R, 3G, and 3B for each light emitting diode and the respective light emitting diodes 2R, 2G, and 2B, between the control signal input terminal 3C and the external terminal 7, and the power supply voltage input terminal 3V and one external terminal 5 and the GND terminal 3E and the other external terminal 6 are electrically connected by a gold wire or the like, respectively. As the internal configuration of the driving IC 3 for the light emitting elements 1C and 1D of the third embodiment, either the driving IC 3 of the first embodiment or the driving IC 3 'of the second embodiment can be adopted.

  According to the light emitting elements 1C and 1D of Example 3 having such a configuration, at least each of the light emitting diodes 2R, 2G, and 2B is provided on the wide lead frame 8 that connects the two other external terminals 6 and 6. Therefore, the heat generated by each of the light emitting diodes 2R, 2G, and 2B can be efficiently radiated through the lead frame 8, so that a large current can flow through each of the light emitting diodes 2R, 2G, and 2B. Or 1D is obtained. Further, the driving IC 3 may also be disposed on the lead frame 8 to improve heat dissipation.

  In Example 4, two types of plastic-molded lamp-type light emitting elements were produced. In the case of a lamp, it is difficult to provide a large number of terminals or to provide complicated wiring on a light emitting diode mounting portion, and complicated control of RGB three-color light emitting diodes can be performed with a small number of terminals such as three terminals. It is very effective if possible. A specific example will be described with reference to FIGS.

  FIG. 9 is a view showing an example of a lamp-type light-emitting element of Example 4, FIG. 9 (a) is a plan view seen through a mold resin, and FIG. 9 (b) is a side view of the same. . In the light emitting element 1E, the light emitting diodes 2R, 2G, and 2B are arranged on the surface of the driving IC 3, and the driving IC 3 is placed on the terminal 6, and each of the light emitting diodes 2R, 2G, and 2B and the driving IC 3 are placed. The external terminals of the driving IC 3 and between the external terminals of the driving IC 3 and the terminals 5 to 7 are wired with a gold wire or the like, and the whole is covered with a light-transmitting mold resin.

  10 is a view showing another aspect of the lamp-type light emitting device of Example 4, FIG. 10 (a) is a plan view seen through the mold resin, and FIG. 10 (b) is also a side view. It is. The light emitting element 1F has the driving IC 3 and the light emitting diodes 2R, 2G, and 2B mounted on the terminal 6, and between the light emitting diodes 2R, 2G, and 2B and the external terminals of the driving IC 3, and the driving IC 3 The external terminal and each of the terminals 5 to 7 are wired with a gold wire or the like, and the whole is covered with a light-transmitting mold resin.

  The light-emitting elements 1E and 1F of Example 4 connect a light-emitting circuit composed of the driving IC 3 and the light-emitting diodes 2R, 2G, and 2B connected thereto between the two external terminals 5 and 6, and the external terminal 7 The circuit configuration is such that the control signal CRGB is input, and each light emitting diode 2R, 2G, 2B can be individually controlled by the same operating principle as the light emitting element 1A of the first embodiment to obtain a desired light emitting color. . As the internal configuration of the driving IC 3 for the light emitting elements 1E and 1F of the fourth embodiment, either the driving IC 3 of the first embodiment or the driving IC 3 'of the second embodiment can be adopted.

  As described above, according to the light emitting element of the present invention, for example, in white light emission by a method using light emitting diodes of three colors of RGB, chromaticity accuracy can be easily and easily performed without performing complicated current control from the outside. It is possible to provide a good light emitting element, and it is possible to improve the color rendering, which is a problem with pseudo white as in the conventional example. It is possible to provide a display with good characteristics.

  Further, the present invention is suitable not only for white light emission but also for controlling multicolor light emission, such as a sequential type liquid crystal display device, by controlling lighting of RGB three primary colors and the like. Since a plurality of light emitting diodes can be controlled with a small number of external terminals, it is also suitable for controlling light emission colors of three or more primary colors of RGB.

FIG. 3 is a perspective view of the light emitting element of Example 1 in a state seen through a mold resin. FIG. 3 is an equivalent circuit diagram illustrating, in a block diagram, a driving IC for the light emitting element according to the first embodiment. 5 is a diagram illustrating a specific example of an internal circuit of a control IC used in Embodiment 1. FIG. 3 is a timing chart for explaining the operation of the driving IC according to the first embodiment. FIG. 6 is an equivalent circuit diagram illustrating, in a block diagram, a driving IC for a light-emitting element according to Example 2. 6 is a diagram illustrating a specific example of an internal circuit of a control IC used in Example 2. FIG. FIG. 6 is a plan view of a light emitting element of Example 3 as seen through a mold resin. FIG. 6 is a plan view of a light-emitting element according to another embodiment of Example 3 as seen through a mold resin. It is a figure which shows an example of the lamp | ramp type light emitting element of Example 4, Fig.9 (a) is a top view which saw through mold resin, FIG.9 (b) is a side view similarly. It is a figure which shows another example of the lamp | ramp type light emitting element of Example 4, Fig.10 (a) is a top view which saw through mold resin, FIG.10 (b) is a side view similarly. It is a light emission intensity-forward current characteristic view of various typical light emitting diodes. It is a spectrum distribution characteristic view of various light emitting diodes.

Explanation of symbols

1A to 1E Light-emitting element 2, 2R, 2G, 2B Light-emitting diode 3, 3 'Driving IC
4 Circuit board 5 to 7 External terminal 8 Lead frame 9 Light transmissive mold resin 11 Current supply circuit 12 3-bit counter circuit 13 Various signal processing circuits 15, 15R, 15G, 15B Driver 17 3 × 3-bit nonvolatile memory 18 Various signals Control circuit 19, 19R, 19G, 19B Driver CRGB Control signal SET Reset terminal

Claims (11)

  A light emitting device in which a plurality of light emitting diodes and a driving IC for driving these light emitting diodes are integrated, wherein the driving IC includes a current supply circuit, a counter, a signal control circuit, and a plurality of bit drivers. A light emitting element.   The light emitting device according to claim 1, wherein the plurality of bit drivers control a current value for each of the plurality of light emitting diodes or a current ratio between the plurality of light emitting diodes to be constant.   2. The light emitting device according to claim 1, wherein the multiple bit driver has a function of finely adjusting a current value for each of the plurality of light emitting diodes or a current ratio between the plurality of light emitting diodes.   4. The light emitting element according to claim 3, wherein the fine adjustment is performed based on correction data stored in a nonvolatile memory built in the driving IC.   3. The light emitting element according to claim 1, wherein the counter circuit of the driving IC is configured to sequentially switch light emission for each of the plurality of light emitting diodes by at least one external signal terminal.   2. The light emitting device according to claim 1, wherein the plurality of light emitting diodes have a light emitting color capable of emitting white light by mixing colors of the light.   The light emitting device according to claim 6, wherein the plurality of light emitting diodes include those that emit light of three primary colors of red, green, and blue.   The light-emitting element according to claim 7, wherein the plurality of light-emitting diodes further have colored light having a center wavelength between red and green.   The light emitting device according to claim 7, wherein the plurality of light emitting diodes further include a light emitting element that emits at least one of orange and yellow light.   The light emitting device according to claim 1, wherein the plurality of light emitting diodes are provided on a surface of the driving IC.   The light emitting device according to claim 1, wherein the plurality of light emitting diodes and the driving IC are covered with the same resin.

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