TW201622171A - Electroluminescence and photoluminescence multi-band white light LED - Google Patents

Abstract

The invention provides an Electroluminescence and photoluminescence multi-band white light LED, comprising an electroluminescence structure, a first photoluminescence layer, a second photoluminescence layer and a red light-emitting layer. The electroluminescence structure emits a violet light having a wavelength of 395 nm to 450 nm and full width at half maximum (FWHM) that is less than 25 nm. The first photoluminescence layer, the second photoluminescence layer and the red light-emitting layer are disposed sequentially on the electroluminescence structure, and the first photoluminescence layer absorbs the violet light to generate a blue light, the second photoluminescence layer absorbs the violet light and the blue light to generate a green light, and the red light-emitting layer generates a red light. Accordingly, the violet light, blue light, green light, and red light are mixed to form a white light with a highly color-rendering property, capable of meeting the requirements of LCD industry and art light.

Description

Electroluminescent and photoluminescent multi-band white light emitting diode

The present invention relates to a white light emitting diode, and more particularly to a white color light emitting diode of high color rendering.

Referring to FIG. 1 , it is a conventional vertical light-emitting diode comprising an N-type semiconductor layer 1A constituting a sandwich structure, an active layer 2A and a P-type semiconductor layer 3A, and the P-type semiconductor layer. A substrate 4A and a P-type electrode 5A are sequentially formed under 3A, and an N-type electrode 6A is provided on the surface of the N-type semiconductor layer 1A.

Accordingly, after the forward bias is applied between the N-type electrode 6A and the P-type electrode 5A, the N-type semiconductor layer 1A and the P-type semiconductor layer 3A respectively provide electrons and holes, and electrons and holes can be used for the activity. The layers 2A are combined to further jump in order to generate excitation light having a fixed wavelength.

Referring to FIG. 2 again, it is a conventional horizontal light-emitting diode, which also includes an N-type semiconductor layer 1B, an active layer 2B and a P-type semiconductor layer 3B constituting a sandwich structure, and the N-type The semiconductor layer 1B is formed on a substrate 4B, and a P-type electrode 5B and an N-type electrode 6B are respectively disposed on the same side of the P-type semiconductor layer 3B and the N-type semiconductor layer 1B, whereby the N-type electrode 6B is After a voltage is applied between the P-type electrodes 5B, electrons and holes can be combined in the active layer 2B to generate excitation light.

Please refer to the patent of US Patent Publication No. US7223998 "White, single or multi-color light emitting diodes by recycling guided modes", which is also a photonic cycle light-emitting diode, which mainly includes a nitride light-emitting diode 9 is sequentially stacked on the nitride light-emitting diode 9 with a non-doped semiconductor layer 9A, a nitride photoactive layer 9B and a non-doped semiconductor layer 9A. The electric laser light 9C (blue light) generated by the nitride light-emitting diode 9 is incident on the nitride photo-photoactive layer 9B to generate another wavelength of photo-induced light 9D (yellow light), in short, nitrogen. The photo-photoactive layer 9B is present in that photo-induced light of another wavelength is produced, that is, the purpose is to mix light of a plurality of colors, which are mixed with a spontaneous red luminescent substance, a photo-excited red phosphorescent substance or a red quantum dot. The red light emitted can produce white light with better color rendering.

Obviously, the prior art discloses the use of the presence of the nitride photoactive layer 9B, absorbing the electric laser 9C (blue light), and thereby generating photo-induced light 9D (yellow light), and mixing them to produce a better color rendering property. White light, however, the actual white light, including red orange yellow green blue purple purple and other colors, it is obvious that the conventional technology does not contain part of the color, its color rendering still can not meet the real white light demand.

Therefore, the main object of the present invention is to disclose a white light emitting diode which has high color rendering property and can meet the requirements of the LCD industry and art lamps.

Based on the above object, the present invention is an electroluminescent and photoluminous multi-band white light emitting diode comprising an electroluminescent structure, a first photoluminescent layer, a second photoluminescent layer and a red light emitting a layer, wherein the electroluminescent structure has an electroluminescence active layer that is biased by a forward bias to emit a wavelength of from 395 nm to 450 nm and a FWHM of less than 25 nm, and is disposed on the electrolysis a P-type semiconductor layer on both sides of the luminescent active layer and a first N-type semiconductor layer, the first photo-emitting layer being disposed on the electroluminescent structure, and the first photo-induced layer The luminescent layer absorbs the violet light to emit a blue light, the second photoluminescent layer is disposed on the first photoluminescent layer with a second N-type semiconductor layer, and the second photoluminescent layer absorbs the violet light, a blue light emitting a green light, the red light emitting layer is sequentially spaced apart by a protective layer, and a third N-type semiconductor layer is disposed on the second photoluminescent layer, the red light emitting layer generates a red light, and the red light, The green light, the blue light and the violet light are mixed to form a high color rendering Sexual white light can meet the requirements of the LCD industry and art lights.

Accordingly, the present invention forms a white light having a high color rendering property through the design of a plurality of light-emitting layers, and the violet light of the present invention is produced by using an electroluminescence structure, and based on the violet light, a photoluminescence method is utilized. The blue light and the green light are generated, and the red light emits light with a relatively mature spontaneous red luminescent material, a light-excited red phosphorescent luminescent material or a red quantum dot. Since the cost of emitting the violet light is relatively low, the present invention is not only Produces white light with high color rendering, and can effectively reduce costs and meet manufacturing needs.

Conventional knowledge

1A, 1B‧‧‧N type semiconductor layer

2A, 2B‧‧‧ active layer

3A, 3B‧‧‧P type semiconductor layer

4A, 4B‧‧‧ substrate

5A, 5B‧‧‧P type electrode

6A, 6B‧‧‧N type electrode

9‧‧‧ nitride light-emitting diode

9A‧‧‧No impurity semiconductor layer

9B‧‧‧Nitride photoactive layer

9C‧‧‧Electric laser

9D‧‧‧Lighting

this invention

10‧‧‧ electroluminescent structure

11‧‧‧electroluminescent active layer

12‧‧‧P type semiconductor layer

13‧‧‧First N-type semiconductor layer

20‧‧‧First photoluminescent layer

30‧‧‧Second photoluminescent layer

31‧‧‧Second N-type semiconductor layer

40‧‧‧Red light layer

50‧‧‧Protective layer

55‧‧‧ Undoped semiconductor layer

60‧‧‧Third N-type semiconductor layer

70‧‧‧N type electrode

80‧‧‧reflective layer

81‧‧‧buffer layer

82‧‧‧ bonding layer

83‧‧‧Substrate

84‧‧‧P type electrode

85‧‧‧current barrier

90‧‧‧ violet

91‧‧‧Blue

92‧‧‧Green light

93‧‧‧Red light

94‧‧‧White light

941‧‧‧Ziguang Bofeng

942‧‧‧Blu-ray wave front

943‧‧‧Green light wave front

944‧‧‧Red Light Wave Front

95, 96‧‧‧ Curve

FIG. 1 is a structural diagram of a conventional vertical light emitting diode.

2 is a structural diagram of a conventional horizontal light emitting diode.

3 is a structural diagram of a conventional photoexcited light emitting diode.

Figure 4 is a structural view of the present invention.

Figure 5 is a spectrum diagram of white light of the present invention.

Figure 6 is a chromaticity coordinate diagram of the CIE 1931 of the present invention.

Fig. 7 is a comparison diagram of the average color rendering evaluation index of the present invention.

The detailed description of the present invention and the technical description of the present invention are further illustrated by the accompanying drawings, but it should be understood that these embodiments are merely illustrative and not to be construed as limiting.

Please refer to FIG. 4 and FIG. 5 together. The present invention is an electroluminescent and photoluminous multi-band white light emitting diode comprising an electroluminescent structure 10 and a first photoluminescence. a layer 20, a second photoluminescent layer 30 and a red luminescent layer 40, wherein the electroluminescent structure 10 has a forward bias voltage and emits a wavelength of 395 nm to 450 nm and a FWHM of less than 25 nm. One of the violet light 90 is an electroluminescent active layer 11, and a P-type semiconductor layer 12 and a first N-type semiconductor layer 13 are disposed on both sides of the electroluminescent active layer 11.

The first photoluminescent layer 20 is disposed on the electroluminescent structure 10, and the first photoluminescent layer 20 absorbs the violet light 90 to emit a blue light 91. The first light is emitted. The material of the light-emitting layer 20 can be selected such that the blue light 91 has a wavelength of 445 nm to 465 nm and a full width at half maximum of more than 20 nm, such as a blue material In _x Ga _1-x N/GaN, x=0.1 ~0.2.

The second photoluminescent layer 30 is disposed on the first photoluminescent layer 20 with a second N-type semiconductor layer 31, and the second photoluminescent layer 30 absorbs the violet light 90 and the blue light 91 to emit a The green light 92, the second photoluminescent layer 30 can be selected such that the green light 92 has a wavelength of 490 nm to 540 nm and a full width at half maximum of more than 20 nm, such as a green light material: In _x Ga _{1 -x} N/GaN, x=0.2~0.3.

The red light emitting layer 40 is sequentially disposed on the second photoluminescent layer 30. The red light emitting layer 40 generates a red light 93, and the red light emitting layer 40 is disposed. It may be any of a spontaneous red luminescent substance, a light-exciting red phosphorescent substance and a red quantum dot, such as a red material: a nitride doping Eu ²⁺ or Mn ⁴⁺ , and the red light 93 wavelength may be 600 奈Rice to 750 nm.

As shown in FIG. 5, the light spectrum of the white light 94 after the light mixing of the present invention shows that the white light 94 has a purple wave front 941, a blue wave front 942, a green light front 943 and a red light wave front 944, that is, it is Violet 90, blue light 91, green light 92 and red light 93 are mixed to form, which has high color rendering, which can meet the requirements of LCD industry and art light.

In order to ensure that the violet light 90 emitted by the electroluminescent active layer 11 is not completely converted into the blue light 91 and the green light 92, the area of the electroluminescent active layer 11 may be greater than or equal to the first photoluminescent layer. 20 and the second photoluminescent layer 30, such that the electroluminescent active layer 11 can ensure that the electrically excited violet light 90 can pass through the first photoluminescent layer 20 and the second photoluminescent layer 30.

In order to supply the electroluminescent active layer 11 in the forward bias direction, the present invention further has an N-type electrode 70 extending through the protective layer 50, the third N-type semiconductor layer 60, and the second light. The light-emitting layer 30, the second N-type semiconductor layer 31 and the first photo-emitting layer 20, and the N-type electrode 70 is in contact with the first N-type semiconductor layer 13; and the P-type semiconductor layer 12 is sequentially under A reflective layer 80, a buffer layer 81, a bonding layer 82, a substrate 83 and a P-type electrode 84 are provided, so that a forward voltage can be supplied between the N-type electrode 70 and the P-type electrode 84 to drive Emits a purple light 90.

For the uniformity of the light, a current blocking layer 85 corresponding to the N-type electrode 70 may be disposed between the reflective layer 80 and the buffer layer 81 to increase the light emission by blocking the current blocking layer 85 and dispersing the current. The uniformity and the position of the current blocking layer 85 can be selected to correspond to the N-type electrode 70 so that the effective light-emitting region avoids the N-type electrode 70 to increase the luminous efficiency.

Further, an undoped semiconductor layer 55 may be disposed between the protective layer 50 and the third N-type semiconductor layer 60. The undoped semiconductor layer 55 may be provided with a structure of light refraction or roughening to enhance brightness.

Please refer to FIG. 6 and FIG. 7 again for comparison of the CIE 1931 chromaticity coordinate map and the average color rendering evaluation index of the present invention; as the above structure and materials used, the white light 94 of the present invention is a seat. Fall in the warm white area (the warm white area in the CIE 1931 color coordinate map range is x: 0.41 ~ 0.50 y: 0.36 ~ 0.45). As shown in FIG. 7, the X-axis is the current value unit of Ampere (A), the Y-axis is the average color rendering index (Ra), and the curve 95 (diamond mark) is the average color rendering index of the white light 94 of the present invention. 96 (square mark) is the average color rendering index of the control group, and the control group uses the general blue LED plus YAG yellow fluorescent powder to produce white light, and the average color rendering index (Ra) of the white light 94 of the present invention can be clearly found. Higher than the control group.

As described above, the present invention mainly transmits a plurality of light-emitting layers to form white light having a high color rendering property, and the present invention utilizes the electroluminescence structure 10 to generate violet light 90, and based on the violet light 90, photoluminescence is utilized. The blue light 91 and the green light 92 are generated in a manner that emits light with a relatively mature spontaneous red luminescent material, a photoexcited red phosphorescent material, or a red quantum dot. Since the cost of emitting the violet light 90 is relatively low, the present invention can not only produce white light 94 having a high color rendering property, but also can effectively reduce the cost and meet the manufacturing requirements.

10‧‧‧ electroluminescent structure

11‧‧‧electroluminescent active layer

12‧‧‧P type semiconductor layer

13‧‧‧First N-type semiconductor layer

20‧‧‧First photoluminescent layer

30‧‧‧Second photoluminescent layer

31‧‧‧Second N-type semiconductor layer

40‧‧‧Red light layer

50‧‧‧Protective layer

55‧‧‧ Undoped semiconductor layer

60‧‧‧Third N-type semiconductor layer

70‧‧‧N type electrode

80‧‧‧reflective layer

81‧‧‧buffer layer

82‧‧‧ bonding layer

83‧‧‧Substrate

84‧‧‧P type electrode

85‧‧‧current barrier

90‧‧‧ violet

91‧‧‧Blue

92‧‧‧Green light

93‧‧‧Red light

Claims (9)

[Item 1]
An electroluminescence and photoluminescence multi-band white light emitting diode comprising:
An electroluminescent structure having an electroluminescence active layer which is subjected to a forward bias and emits a wavelength of from 395 nm to 450 nm and a full width at half maximum of less than 25 nm. a P-type semiconductor layer on both sides of the electroluminescent active layer and a first N-type semiconductor layer;
a first photoluminescent layer, the first photoluminescent layer is disposed on the electroluminescent structure, and the first photoluminescent layer absorbs the violet light to emit a blue light;
a second photoluminescent layer disposed on the first photoluminescent layer with a second N-type semiconductor layer, and the second photoluminescent layer absorbing the violet light and the blue light a green light
a red light emitting layer, the red light emitting layer is sequentially spaced apart by a protective layer, and a third N-type semiconductor layer is disposed on the second photoluminescent layer, the red light emitting layer generates a red light, and the red light and the green light Light, the blue light is mixed with the violet light to form a white light. [Item 2]
The electroluminescent and photoluminescent multi-band white light emitting diode according to claim 1, wherein the red light emitting layer is any one of a spontaneous red light emitting material, a light emitting red phosphorescent material and a red quantum dot. [Item 3]
The electroluminescent and photoluminescent multi-band white light emitting diode according to claim 1, wherein the blue light has a wavelength of 445 nm to 465 nm and a full width at half maximum of more than 20 nm. [Item 4]
The electroluminescent and photoluminescent multi-band white light emitting diode according to claim 1, wherein the green light has a wavelength of 490 nm to 540 nm and a full width at half maximum of more than 20 nm. [Item 5]
The electroluminescent and photoluminescent multi-band white light emitting diode according to claim 1, wherein the red light has a wavelength of from 600 nm to 750 nm. [Item 6]
The electroluminescent and photoluminous multi-band white light emitting diode according to claim 1, wherein the area of the electroluminescent active layer is greater than or equal to the first photoluminescent layer and the second photoluminescence. Floor. [Item 7]
The electro-optic and photo-optic multi-band white light-emitting diode according to claim 1, wherein the N-type electrode further has an N-type electrode, the N-type electrode penetrating the protective layer, the third N-type semiconductor layer, The second photoluminescent layer, the second N-type semiconductor layer and the first photoluminescent layer, and the N-type electrode is in contact with the first N-type semiconductor layer; and the P-type semiconductor layer is sequentially disposed under the P-type semiconductor layer a reflective layer, a buffer layer, a bonding layer, a substrate and a P-type electrode. [Item 8]
The electro-optic and photo-optic multi-band white light-emitting diode according to claim 7, wherein a current blocking layer corresponding to the N-type electrode is disposed between the reflective layer and the buffer layer. [Item 9]
The electro-optic and photo-optic multi-band white light-emitting diode according to claim 1, wherein an undoped semiconductor layer is further disposed between the protective layer and the third N-type semiconductor layer.