JPH075645Y2 - Full color light emitting element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a full-color light emitting device used for light emitting display in an LED color television, for example.

<Prior Art> A conventional full-color light emitting device will be described below with reference to the drawings. 9 to 11 are drawings for explaining a conventional full-color light emitting device, and FIG. 9 is a vertical sectional front view,
FIG. 10 is an electrical equivalent circuit diagram, and FIG. 11 is a vertical sectional front view of a collective type light emitting device corresponding to the full-color light emitting device shown in FIG.

As shown in FIG. 9, a conventional full-color light emitting device has three LED chips 1a, 1b, and 1c each having red, green, and blue emission colors and an N-type conductive layer 7 of each of these LED chips. Lead terminal 3d attached by conductive adhesive 2, lead terminals 3a, 3b, 3c, and LED chip 1
The P-type conductive layers 8 of a, 1b, and 1c are connected to the lead terminals 3a and 3 respectively.
Conductive wire 4 connected to b, 3c and lead terminals 3a, 3
It is provided with an upper part of b, 3c, 3d, LED chips 1a, 1b, 1c, and a light-transmissive encapsulant 5 such as an epoxy resin encapsulating the conductive wire 4. The LED chips 1a, 1b, 1c forming such a full-color light emitting element are connected in parallel as shown in FIG.

FIG. 11 shows a full-color light emitting element in the case where the LED chips 1a, 1b, 1c are individually sealed, and is composed of red, green and blue light emitting elements 6a, 6b, 6c.
The red light emitting element 6a is an LED chip 1a having a red light emission color.
And the N-type conductive layer 7 of this LED chip 1a is a conductive adhesive 2
Attached to the P-type conductive layer 8 of the LED chip 1a by the conductive wire 4 and the lead terminal 31d, the top of the lead terminal 31d, LED
It is provided with a translucent sealing material 5a such as an epoxy resin which seals the chip 1a and the conductive wire 4a. The green and blue light emitting elements 6b and 6c have the same structure as the red light emitting element 6a, and the green light emitting element 6b emits green light LED chip 1b,
The lead terminal 32d, the lead terminal 3b and the sealing material 5b, the blue light emitting element 6c is an LED chip 1c that emits blue light, the lead terminal 3
3d, a lead terminal 3b and a sealing material 5c. The lead terminals 31d, 32d, 33d are connected at the connection point 3d, and the light emitting elements 6a, 6
b and 6c are used as a set of full color light emitting devices. The electrical circuit is the same as the electrical equivalent circuit diagram shown in FIG.

<Problems to be Solved by the Invention> However, the above-described conventional full-color light emitting device has the following drawbacks. That is, the full-color light-emitting device described in FIG. 9 has four lead terminals, and therefore the size of the full-color light-emitting device is large.
Further, the full-color light-emitting element described in FIG. 11 is also a full-color light-emitting element in which three light-emitting elements of red, green, and blue, which are individually sealed, are gathered into one unit, and therefore, as a full-color light-emitting unit, The occupied area becomes large. In a color television or the like, it is desired to increase the degree of integration of the full-color light emitting elements in order to improve the sharpness of the image. However, if the size of the full-color light emitting elements is large, it is difficult to increase the degree of integration.

Also, regarding the driving method of the full-color light emitting element,
Conventional full-color light emitting devices are suitable for CD drive or dynamic drive by general pulse current. However, it is impossible to use a three-phase alternating current, which is a power source that can be used when installing an industrial television or the like, as a direct drive power source for a full-color light emitting element.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a full-color light emitting device that is small in size and can use a three-phase alternating current directly as a driving power supply.

<Means for Solving the Problems> In order to solve the above problems, the full-color light emitting device of the present invention emits red, green, and blue light, respectively, and has first, second, and third LED chips connected in delta. Then, the first, second, and third LED chips are respectively applied with the voltages of the first, second, and third phases of a three-phase alternating current, and the voltages are changed for each phase to emit a desired color. I am trying to let you.

<Operation> A desired color is emitted by applying a voltage of the first, second and third phases of a three-phase alternating current to each of the first, second and third LED chips and changing the voltage for each phase. Let

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings. First
1 to 5 are drawings for explaining a first embodiment of the present invention, wherein FIG. 1 is a longitudinal front view, FIG. 2 is a plan view, and FIG. 3 is a partially enlarged view of FIG. FIG. 4 and FIG. 4 are electrical equivalent circuit diagrams, and FIG. 5 is an explanatory diagram of applied voltage in a driving state of the full-color light emitting element. 6 to 8 show the second of the present invention.
FIGS. 6 and 7 are views for explaining the embodiment of FIG.
FIG. 8 and FIG. 8 are drawings corresponding to FIG. 3, FIG. 2 and FIG. 4 of the first embodiment, respectively. The same or similar components as those described in the related art will be designated by the same reference numerals.

As shown in FIG. 1, the full-color light emitting device 100 of the first embodiment has an LED chip 1a (first LED chip) that emits red light, an LED chip 1b (second LED light emitting chip) that emits green light, and a blue light emission device. It has an LED chip 1c (third LED chip). Then, as shown in FIG. 3, each of the LED chips 1a, 1b, and 1c has a laminated first
It has an N-type conductive layer 7 which is a conductive layer and a P-type conductive layer 8 which is a second conductive layer. In addition, the full-color light emitting device 100
Is a lead terminal 3a (first lead terminal) having the N-type conductive layer 7 of the LED chip 1a attached to the upper end (upper side in FIG. 1) by a conductive adhesive 2 such as silver paste, the LED chip 1b.
Lead terminal 3b (second lead terminal) having the N-type conductive layer 7 attached to the upper end with the conductive adhesive 2 and the lead having the N-type conductive layer 7 of the LED chip 1c attached to the upper end with the conductive adhesive 2. And a terminal 3c (third lead terminal). Then, between the P-type conductive layer 8 of the LED chip 1a and the lead terminal 3c, between the P-type conductive layer 8 of the LED chip 1b and the lead terminal 3c.
The wires a and the P-type conductive layer 8 of the LED chip 1c and the lead terminals 3b are connected by conductive wires 4 such as gold. Furthermore, the upper part of the lead terminals 3a, 3b, 3c, the LED chip 1
The a, 1b, 1c and the wire 4 are sealed with a translucent sealing material 5 such as an epoxy resin as shown in FIGS. 1 and 2. The lead terminals 3a, 3b and 3c are arranged such that their longitudinal directions are substantially parallel to each other and the LED chips 1a, 1b and 1c are substantially at the same height and aligned. The electric circuit of the full-color light emitting device 100 having such a structure is in a delta connection as shown in FIG.

Next, the operation of the full-color light emitting device 100 of this embodiment will be described.

Since the full-color light-emitting device 100 is in the delta connection as described above, in order to drive the full-color light-emitting device 100, a three-phase AC voltage is applied to the lead terminals 3a, 3b and 3c. Then, the LED chips 1a, 1b, and 1c do not light up at the same time in a strict sense, but since they blink at high frequency, the visual illusion that they appear to be continuous lighting up to the human eye is used. Can emit full-color light by using the driving method described below.

When a voltage is applied between the lead terminals 3c and 3a so that a forward current flows in the LED chip 1a, the LED characteristics cause the LED
Since a reverse voltage is applied to the chips 1b and 1c and no current flows, only the LED chip 1a lights up. Lead terminals 3a, 3
If a voltage is applied between b so that a forward current flows through the LED chip 1b, no current will flow through the LED chips 1c and 1a.
Only the ED chip 1b lights up. If a voltage is applied between the lead terminals 3b and 3c so that a forward current flows through the LED chip 1c, no current will flow through the LED chips 1a and 1b.
Only chip 1c lights up.

Therefore, when the lead terminals 3a, 3b and 3c are connected to a high frequency three-phase AC power supply, that is, between the lead terminals 3c and 3a, between the lead terminals 3a and 3b and between the lead terminals 3b and 3c, FIG. As shown in, when the voltage of each phase of the three-phase AC voltage with the same voltage of each phase is applied, the LED chip 1
The red light emission of a, the green light emission of the LED chip 1b, and the blue light emission of the LED chip 1c are repeated at high speed, and as a result, visually white light emission can be obtained.

In addition, as shown in FIG. 5 (b), a voltage applied between the lead terminals 3c and 3a, between the lead terminals 3a and 3b, and between the lead terminals 3b and 3c is passed through a modulation circuit (not shown) to generate large and small differences. Then, the magnitude of the current flowing through the LED chips 1a, 1b, 1c,
That is, the waveform is different for each LED chip. And LED chip 1a lighting, LED chip 1b lighting and LE
Since the lighting of the D chip 1c is sequentially repeated, it is possible to obtain light emission of a desired color by adjusting the luminance of the LED chips 1a, 1b, 1c by adjusting the magnitude of the energizing current for each LED chip in this way. .

Next, a second embodiment will be described. The same components as those described in the first embodiment are designated by the same reference numerals. As shown in FIGS. 6 and 7, the full color light emitting device 200 of the second embodiment is the full color light emitting device 100 of the first embodiment.
Similarly, LED chip 1a (first LED chip) that emits red light and LED chip 1b (second LED chip) that emits green light
And an LED chip 1c (third LED chip) that emits blue light, and each of these LED chips 1a, 1b, 1c has an N-type conductive layer 7 and a P-type conductive layer 8 that are stacked. .

In addition, the full-color light-emitting device 200 has a lead terminal 3a (first lead terminal) in which the N-type conductive layer 7 of the LED chip 1a is attached to the upper end by the conductive adhesive 2, the N-type conductive layer 7 of the LED chip 1b and the LED chip. The P-type conductive insert 8 of 1c is provided with a lead terminal 3d (second lead terminal) and a lead terminal 3e (third lead terminal) attached to the upper end by a conductive adhesive 2. Then, between the P-type conductive layer 8 of the LED chip 1a and the lead terminal 3e, between the P-type conductive layer 8 of the LED chip 1b and the lead terminal 3a, and between the N-type conductive layer 7 and the lead terminal 3 of the LED chip 1c.
The portions e are connected by a conductive wire 4 such as gold. Furthermore, the upper part of the lead terminals 3a, 3d, 3e, the LED chip 1
The a, 1b, 1c and the wire 4 are sealed with a translucent sealing material 5 such as an epoxy resin. LED chips 1a, 1
The lead terminals 3a, 3d, and 3e are arranged so that b and 1c have substantially the same height and are located at the vertices of a substantially equilateral triangle in a plan view. Full-color light emitting device having such a structure
The electric circuit of 200 also has a delta connection as shown in FIG. The operation of the full-color light emitting device 200 of the second embodiment is similar to that of the first embodiment, so its explanation is omitted.

In the first and second embodiments described above, the first conductive layer of the LED chips 1a, 1b, 1c is described as the N-type conductive layer and the second conductive layer is the P-type conductive layer. The first conductive layer is a P-type conductive layer, and the second conductive layer is N.
The same effect can be obtained even with the type conductive layer. Further, both the N-type conductive layer 7 and the P-type conductive layer 8 are formed on the surface opposite to the joint surface between the N-type conductive layer 7 and the P-type conductive layer 8, respectively. An electrode (not shown) is formed as a part of the electrode. In practice, the wire 4 is connected to the electrode by wire bonding, or the electrode is attached to the lead terminal by the conductive adhesive 2.

<Effect of Device> As described above, the full-color light emitting device of the present invention is such that the LED chip that emits red light, the LED chip that emits green light, and the LED chip that emits blue light are connected in delta, and The number of lead terminals for applying a voltage to these LED chips is one less than the number of lead terminals of a conventional full-color light emitting device.

Therefore, since the full-color light-emitting device of the present invention has a compact external size, it is possible to mount a large number of full-color light-emitting devices on a single substrate with high density. In addition, the image quality can be improved and a clear image can be taken out. Also these
Since the LED chips are connected in delta, the voltage of each phase of the three-phase alternating current is applied to each LED chip, and this voltage is changed for each phase to make the conduction current of each LED chip different and A desired color can be emitted depending on the brightness balance. That is, there is also an advantage that high-speed three-phase alternating current can be directly used as a driving power source.

[Brief description of drawings]

1 to 5 are drawings for explaining a first embodiment of the present invention, in which FIG. 1 is a longitudinal front view, FIG. 2 is a plan view, and FIG. 3 is one of FIG. 4 is an electrically equivalent circuit diagram, FIG. 5 is an explanatory diagram of an applied voltage in a driving state of a full-color light emitting device, FIG. 5A is a case where voltages of respective phases are equal, and FIG. The case where the voltage of each phase is different is shown. FIGS. 6 to 8 are drawings for explaining the second embodiment of the present invention, and FIGS. 6, 7 and 8 are
5 is a drawing corresponding to FIG. 3, FIG. 2 and FIG. 4 of the first embodiment, respectively. 9 to 11 are drawings for explaining a conventional full-color light emitting device. FIG. 9 is a vertical sectional front view, FIG. 10 is an electrical equivalent circuit diagram, and FIG. 11 is shown in FIG. FIG. 3 is a vertical sectional front view of a collective type light emitting element corresponding to a full-color light emitting element. 1a, 1b, 1c ... LED chip, 3a, 3b, 3c, 3d, 3e ... Lead terminal, 4 ... Wire, 5 ... Sealing material, 7 ... N-type conductive layer, 8 ... P-type conductivity Layer, 100, 200 ... Full color light emitting device.

Claims (1)

[Scope of utility model registration request] 1. A red light emitting device, a green light emitting device, and a blue light emitting device, respectively.
Delta-connected first, second and third LED chips, said first, second and third LED chips respectively,
A full-color light-emitting device, characterized in that first, second, and third-phase voltages of three-phase alternating current are applied, and the voltages are changed for each phase to emit a desired color.