Light emitting diode

Abstract

The invention relates to a light-emitting diode, which is provided with a multiple quantum well structure to generate a light beam with a broadband blue light spectrum, and the light beam comprises a first sub-light beam with a first wavelength, a second sub-light beam with a second wavelength and a third sub-light beam with a third wavelength, the difference value between the first wavelength and the second wavelength ranges from 1 nm to 50 nm, the difference value between the first wavelength and the third wavelength ranges from 20 nm to 70 nm, and the difference value between the second wavelength and the third wavelength ranges from 10 nm to 30 nm. And the light beam emitted by the light emitting diode has the photoelectric conversion efficiency of more than 0.45 under the operating current density of 120mA / mm < 2 >.

Description

Technical Field

[0001] The invention relates to a light emitting diode, in particular to a light emitting diode for generating a wide-band spectrum. Background Art

[0002] In the prior art, narrow-peak blue light emitting diodes (LEDs) are usually used to excite phosphors to generate white light as an illumination source or display light source. In the white light spectrum generated by the above method, blue light appears as a high-intensity peak. Therefore, how to make the blue light spectrum generated by the blue light emitting diode closer to the waveform of the standard light source in the blue light band, so that the white light spectrum generated by the blue light emitting diode combined with the phosphor is close to the natural light spectrum, is still the direction of efforts of those skilled in the art. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a light emitting diode to generate a wide-band spectrum.

[0004] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light emitting diode having a multi-quantum well structure to generate a light beam with a broadband blue light spectrum, and the light beam includes a first sub-beam with a first wavelength and a second sub-beam with a second wavelength, wherein the difference between the first wavelength and the second wavelength is between 1nm and 50nm, and at an operating current density of 120mA / mm 2 Under this condition, the photoelectric conversion efficiency of the light-emitting diode is greater than 0.45.

[0005] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light-emitting diode, which includes a P-type semiconductor layer, an N-type semiconductor layer and a light-emitting stack. The light-emitting stack is located between the N-type semiconductor layer and the P-type semiconductor layer. The light-emitting stack includes a plurality of well layers for generating a plurality of sub-beams, the plurality of well layers include a first well layer for generating a first sub-beam, a first wavelength of the first sub-beam is greater than the wavelengths of the remaining sub-beams, and the first well layer and the P-type semiconductor layer are separated by at least another well layer, and the wavelength of the sub-beam generated by the other well layer is less than the first wavelength.

[0006] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light emitting diode, which includes: a first well layer for generating at least a first sub-beam, the first sub-beam has a first wavelength and a first light intensity; and a second well layer for generating at least a second sub-beam, the second sub-beam has a second wavelength and a second light intensity. The first light intensity is less than the second light intensity, and when the current density of the light emitting diode is 100mA / mm 2 Up to 300mA / mm 2When changing, the ratio of the first light intensity to the second light intensity is between 0.1 and 0.9.

[0007] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light emitting diode, which includes: a first well layer for generating at least a first sub-beam, the first sub-beam having a first wavelength and a first light intensity; and a second well layer for generating at least a second sub-beam, the second sub-beam having a second wavelength and a second light intensity. The first light intensity is less than the second light intensity, and when the operating temperature of the light emitting diode is between 25°C and 85°C, the ratio of the first light intensity to the second light intensity is between 0.1 and 0.9.

[0008] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light-emitting diode, which includes at least one first well layer and at least one second well layer. The first well layer has a first indium concentration, and the second well layer has a second indium concentration. The difference between the first indium concentration and the second indium concentration is at least 0.5%.

[0009] In order to solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is to provide a light-emitting diode, which includes a P-type semiconductor layer, an N-type semiconductor layer and an alternating stacking structure. The alternating stacking structure is located between the N-type semiconductor layer and the P-type semiconductor layer. The alternating stacking structure includes a plurality of well layers, the plurality of well layers include a first well layer having a first indium concentration, and the first indium concentration is greater than the indium concentration of the remaining well layers. The plurality of well layers also include a second well layer, and the second well layer has a second indium concentration. The first well layer and the P-type semiconductor layer are separated by at least another well layer, and the difference between the first indium concentration and the second indium concentration is at least 0.5%.

[0010] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light-emitting diode, which includes a P-type semiconductor layer, an N-type semiconductor layer and an alternating stacking structure. The alternating stacking structure is located between the N-type semiconductor layer and the P-type semiconductor layer. The alternating stacking structure includes a plurality of well layers for generating a plurality of sub-beams, the wavelength of the sub-beam generated by each well layer differs from the wavelength of the sub-beam generated by the most adjacent well layer by at least 1 nm, and the well layer closest to the P-type semiconductor layer is used to generate a sub-beam with the shortest wavelength.

[0011] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a light-emitting diode. A light-emitting stack of the light-emitting diode includes a plurality of well layers and a plurality of barrier layers stacked alternately, wherein the plurality of well layers have the same thickness, and the thickness of one barrier layer differs from the thickness of another barrier layer by at least 5%.

[0012] To sum up, one of the beneficial effects of the present invention is that, through the technical means of "multiple well layers are at least divided into a first well layer and a second well layer" in the epitaxial light-emitting structure of the light-emitting diode provided in the embodiment of the present invention, the light-emitting spectrum of the epitaxial light-emitting structure can have a larger half-width or multiple peaks.

[0013] To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and description and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. 4 is a cross-sectional schematic diagram of a light emitting diode module according to one embodiment of the present invention.

[0015] Figure 2 FIG. 4 is a schematic diagram of a light emitting diode according to one embodiment of the present invention.

[0016] Figure 3 FIG. 1 is a schematic diagram of a light-emitting stack according to a first embodiment of the present invention.

[0017] Figure 4 Schematic diagram of the bandgap structure of the light-emitting stack according to the first embodiment of the present invention.

[0018] Figure 5 Spectrum of broadband blue light of the light emitting diode according to the first embodiment of the present invention.

[0019] Figure 6 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the second embodiment of the present invention.

[0020] Figure 7 Schematic diagram of the bandgap structure of the light-emitting stack according to the third embodiment of the present invention.

[0021] Figure 8 Spectrum of broadband blue light from a light emitting diode according to the third embodiment of the present invention.

[0022] Fig. 9 The wide-band blue light spectra of different light-emitting diodes of the present invention are measured before packaging.

[0023] Fig.10 Spectra of broadband blue light of a light emitting diode under different operating currents according to an embodiment of the present invention.

[0024] Fig.11 Spectra of broadband blue light of a light emitting diode under different operating temperatures according to an embodiment of the present invention.

[0025] Fig.12 FIG. 4 is a schematic diagram of the bandgap structure of the light-emitting stack according to the fourth embodiment of the present invention.

[0026] Fig.13 FIG. 4 is a schematic diagram of the bandgap structure of the light-emitting stack according to the fifth embodiment of the present invention.

[0027] Fig.14 Schematic diagram of the bandgap structure of the light-emitting stack according to the sixth embodiment of the present invention.

[0028] Fig.15 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the seventh embodiment of the present invention.

[0029] Fig.16 Schematic diagram of the bandgap structure of the light-emitting stack according to the eighth embodiment of the present invention.

[0030] Fig.17 Spectra of broadband blue light of the light emitting diodes of the seventh and eighth embodiments of the present invention.

[0031] Fig.18 FIG. 4 is a schematic diagram of the bandgap structure of the light-emitting stack according to the ninth embodiment of the present invention.

[0032] Fig.19 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the tenth embodiment of the present invention.

[0033] Fig. 20 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the eleventh embodiment of the present invention.

[0034] Fig.21 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the twelfth embodiment of the present invention.

[0035] Fig. 22 Spectra of broadband blue light of the light emitting diode of the twelfth embodiment of the present invention before and after packaging.

[0036] Fig.23 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the thirteenth embodiment of the present invention.

[0037] Fig.24 Spectrum of broadband blue light of the light emitting diode according to the thirteenth embodiment of the present invention.

[0038] Fig.25 Schematic diagram of the bandgap structure of the light-emitting stack according to the fourteenth embodiment of the present invention.

[0039] Fig.26 Schematic diagram of the bandgap structure of the light-emitting stack according to the fifteenth embodiment of the present invention.

[0040] Fig. 27 Schematic diagram of the bandgap structure of the light-emitting stack according to the sixteenth embodiment of the present invention.

[0041] Fig.28FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the seventeenth embodiment of the present invention.

[0042] Fig.29 1 is the photoelectric conversion efficiency of the light emitting diodes according to different embodiments of the present invention. DETAILED DESCRIPTION

[0043] The following is an explanation of the implementation of the "light emitting diode" disclosed in the present invention through specific examples. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following implementations will further explain the relevant technical contents of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention.

[0044] Please refer to Figure 1 , Figure 1 FIG. 1 is a cross-sectional view of a light emitting diode module according to an embodiment of the present invention. In the embodiment of the present invention, the light emitting diode module Z1 is used to generate white light, and the spectrum of the white light is a full spectrum or a healthy spectrum.

[0045] like Figure 1 As shown, the light emitting diode module Z1 includes a substrate Z10, a reflective component Z11, a light emitting component Z12 and a wavelength conversion layer Z13.

[0046] A die-bonding area is defined on the substrate Z10. In one embodiment, the material of the substrate Z10 may be selected to have high thermal conductivity, high reflectivity for visible light beams, and low transmittance, such as metal or ceramic. In other embodiments, the substrate Z10 may also include a high thermal conductivity substrate and a reflective layer coated on the high thermal conductivity substrate. The present invention does not limit the material of the substrate Z10 to a single material or a composite material.

[0047] The reflective component Z11 and the light emitting component Z12 are disposed together on the substrate Z10 to reflect and guide the light beam generated by the light emitting component Z12 to a specific direction. The reflective component Z11 is disposed around the die-bonding area and defines a receiving space.

[0048] The light emitting component Z12 is disposed in the die-bonding region of the substrate Z10 and is located in the accommodation space defined by the reflective component Z11, so as to generate a light beam with a wide-band blue light spectrum, and the half-height width of the spectrum waveform of the light beam is at least greater than 20 nm.

[0049] In one embodiment, the light emitting element Z12 includes at least one light emitting diode, and the light emitting diode can be used to generate a light beam with a broadband blue light spectrum. The detailed structure of the light emitting diode will be further described below.

[0050] In another embodiment, the light emitting element Z12 may also include a plurality of light emitting diodes, and the plurality of light emitting diodes respectively generate a plurality of blue light beams with different peak wavelengths. The plurality of blue light beams with different peak wavelengths are mixed to form the aforementioned wide-band blue light.

[0051] The wavelength conversion layer Z13 fills the space defined by the reflective component Z11 and covers the light emitting component Z12. The wide-band blue light generated by the light emitting component Z12 can generate white light with a specific spectrum through the wavelength conversion layer Z13. In the embodiment of the present invention, the spectrum of the white light generated by the light emitting diode module Z1 is a full spectrum and is closer to the spectrum of natural light.

[0052] In one embodiment, the wavelength conversion layer Z13 includes at least a green phosphor and a red phosphor. The material of the green phosphor may be lumine aluminum garnet (LuAG) or gallium-containing yttrium aluminum garnet (YGaAG) phosphor, and the material of the red phosphor may be aluminum silicon nitride, such as calcium aluminum silicon nitride (CASN) or silicon nitrogen compound (Sr2Si5N8) or sulfur selenium compound (Ca2SeS). In another embodiment, the wavelength conversion layer Z13 may further include a yellow phosphor. The material of the yellow phosphor is, for example, yttrium aluminum garnet (YAG).

[0053] It should be noted that light beams of different wavelengths have different excitation efficiencies for green phosphors. Based on the material differences of green phosphors, green phosphors have the best excitation efficiency in a specific wavelength band. As mentioned above, in this embodiment, the light emitting component Z12 includes at least one light emitting diode, and the light emitting diode itself can generate a light beam with a wide-band blue light spectrum. The detailed structure of the light emitting diode of one embodiment of the present invention is further described below.

[0054] Please refer to Figures 2 to 4 , Figure 2 FIG. 4 is a schematic diagram of a light emitting diode according to one embodiment of the present invention. Figure 3 is a schematic diagram of a light emitting stack according to a first embodiment of the present invention, and Figure 4 Schematic diagram of the bandgap structure of the light-emitting stack according to the first embodiment of the present invention.

[0055] The light emitting diode M of the embodiment of the present invention comprises a substrate 1, a buffer layer 2, an epitaxial light emitting structure 3, a first electrode 4 and a second electrode 5. The material of the substrate 1 may be sapphire, silicon carbide, gallium nitride or silicon or other materials suitable for crystal growth. In the present embodiment, the material of the substrate 1 is sapphire. The buffer layer 2 is formed on the substrate 1 by an epitaxial process and has a lattice constant that matches the material of the substrate 1 and the material of the epitaxial light emitting structure 3. In one embodiment, the material of the buffer layer 2 may be aluminum nitride or gallium nitride.

[0056] Please continue to refer to Figure 2 The epitaxial light emitting structure 3 is disposed on the buffer layer 2 and has an N-type semiconductor layer 30, a P-type semiconductor layer 31 and a light emitting stack 32. In this embodiment, the N-type semiconductor layer 30 is disposed on the buffer layer 2, and the light emitting stack 32 and the P-type semiconductor layer 31 are sequentially disposed on the N-type semiconductor layer 30.

[0057] In addition, the width of the light emitting stack 32 and the width of the P-type semiconductor layer 31 are both smaller than the width of the N-type semiconductor layer 30, thereby exposing a portion of the N-type semiconductor layer 30. In other words, the light emitting stack and the P-type semiconductor layer 31 together form a platform portion. Figure 2 The illustrated embodiment is not intended to limit the present invention. In other embodiments, the positions of the N-type semiconductor layer 30 and the P-type semiconductor layer 31 may also be interchanged.

[0058] The first electrode 4 and the second electrode 5 are electrically connected to the N-type semiconductor layer 30 and the P-type semiconductor layer 31, respectively, so as to be electrically connected to an external control circuit. In this embodiment, the first electrode 4 is disposed on the N-type semiconductor layer 30, and the second electrode 5 is disposed on the P-type semiconductor layer 31 (i.e., the platform portion).

[0059] Furthermore, the N-type semiconductor layer 30 and the P-type semiconductor layer 31 are respectively an electron supply layer and a hole supply layer to provide electrons and holes respectively. In one embodiment, the material of the N-type semiconductor layer 30 is silicon-doped gallium nitride. In addition, the material of the P-type semiconductor layer 31 is magnesium-doped gallium nitride or magnesium-doped aluminum gallium nitride.

[0060] The light emitting stack 32 is located between the N-type semiconductor layer 30 and the P-type semiconductor layer 31 and has a first side 32a close to the N-type semiconductor layer 30 and a second side 32b close to the P-type semiconductor layer 31. The light emitting stack 32 is used to generate a light beam with a broadband blue light spectrum.

[0061] In detail, by applying a bias voltage to the first electrode 4 and the second electrode 5 through an external control circuit, a current can be generated through the N-type semiconductor layer 30, the light-emitting stack 32 and the P-type semiconductor layer 31, and the light-emitting stack 32 is excited to generate a light beam with a specific wavelength. In this embodiment, the waveform of the wide-band blue light spectrum generated by the light-emitting stack 32 has a wider half-maximum width (FWHM) or has multiple peaks. In one embodiment, the half-maximum width of the spectrum waveform of the light beam is at least greater than 20nm.

[0062] Please refer to Figure 3 as well as Figure 4 In this embodiment, the light emitting stack 32 is an alternating stack structure and has a multiple quantum well structure. That is, the light emitting stack 32 includes a plurality of barrier layers 320 and a plurality of well layers 321 that are alternately stacked. Figure 3 As shown, the thickness T of each barrier layer 320 is greater than the thickness t of any well layer 321 .

[0063] The thickness T of the barrier layer 320 and the thickness t of the well layer 321 affect the spectral waveform of the broadband blue light finally generated by the light-emitting stack 32. It should be noted that the thickness of the existing barrier layer is only about 2 to 3.5 times the thickness of the well layer. Specifically, the thickness of the existing barrier layer ranges from 8.5 nm to 10.5 nm. However, when the operating current changes, the spectral shape is easily changed.

[0064] Accordingly, in an embodiment of the present invention, the ratio of the thickness T of the barrier layer 320 to the thickness t of the well layer 321 ranges from 2.5 to 5 times, preferably 3 to 4 times. Thus, compared with the prior art, the present invention can reduce the impact of the operating current change on the spectral waveform. Preferably, the thickness T of the barrier layer 320 ranges from 8.5 nm to 15 nm, preferably from 9.5 nm to 15 nm. In addition, the thickness t of the well layer 321 ranges from 2.5 nm to 4.5 nm.

[0065] In addition, although in the present embodiment, the thickness t of the multilayer well layer 321 is substantially the same, the present invention is not limited thereto. In other embodiments, the thickness T of the multilayer barrier layer 320 is not necessarily the same, and the thickness t of the multilayer well layer 321 is not necessarily the same. For example, at least two barrier layers 320 in the multilayer barrier layer 320 may have different thicknesses, or at least two well layers 321 in the multilayer well layer 321 may have different thicknesses.

[0066] Please refer to Figure 4 The bandgap width of each barrier layer 320 is greater than the bandgap width of any well layer 321, so that the light-emitting stack 32 has a multiple quantum well structure.

[0067] In this embodiment, the plurality of well layers 321 may have a plurality of different bandgap widths to generate a plurality of sub-beams with different wavelengths. The plurality of sub-beams may be superimposed on each other to form a beam with a wide-band blue light spectrum.

[0068] In this embodiment, the plurality of well layers 321 can be divided into a first well layer 321a, a second well layer 321b, and a third well layer 321c according to the size of the bandgap width. The bandgap width Eg1 of the first well layer 321a is smaller than the bandgap width Eg2 of the second well layer 321b, and the bandgap width Eg2 of the second well layer 321b is smaller than the bandgap width Eg3 of the third well layer 321c.

[0069] It should be noted that the bandgap width of the well layer 321 is inversely proportional to the wavelength of the generated light beam. That is, the larger the bandgap width of the well layer 321, the smaller the wavelength of the sub-beam generated by the well layer 321. Accordingly, the first well layer 321a can be used to generate a first sub-beam with a first wavelength. The second well layer 321b is used to generate a second sub-beam with a second wavelength, and the third well layer 321c is used to generate a third sub-beam with a third wavelength. In one embodiment, the difference between the first wavelength and the second wavelength is between 1nm and 50nm.

[0070] In one embodiment, the difference between the first wavelength and the third wavelength ranges from 20 nm to 70 nm. Further, the difference between the first wavelength and the second wavelength ranges from 10 nm to 30 nm, and the difference between the second wavelength and the third wavelength ranges from 10 nm to 30 nm.

[0071] The well layer 321 can have different bandgap widths according to the desired spectral shape, thereby adjusting the difference range between the wavelengths of any two of the first sub-beam, the second sub-beam and the third sub-beam (such as the first and second wavelengths, the first and third wavelengths or the second and third wavelengths).

[0072] In addition, by coordinating the excitation characteristics of the green phosphor in the wavelength conversion layer Z13 and making the spectrum of the broadband blue light closer to the waveform of the standard light source in the blue light band, the light beam with better excitation efficiency for the green phosphor will have a greater intensity.

[0073] Based on the above, in this embodiment, the plurality of well layers 321 are used to generate light beams with wavelengths in the blue light band, but the light beams generated by the first well layer 321a, the second well layer 321b and the third well layer 321c have different peak wavelengths.

[0074] Furthermore, the barrier layer 320 is a gallium nitride (GaN) layer, and the well layer 321 is an indium gallium nitride (In x Ga 1-xSince the indium concentration in the well layer 321 affects the bandgap width of the well layer 321, the bandgap width of the well layer 321 can be adjusted by controlling the indium concentration in each well layer, thereby controlling the emission wavelength of the well layer 321. Please refer to Table 1 below, which shows the relationship between the indium concentration (%) in the well layer 321 and the wavelength of the sub-beam through theoretical calculation.

[0075] Table 1

[0076] Wavelength (nm) 430 435 440 445 450 455 460 465 470 Indium concentration (%) 12.4 13.3 14.1 14.9 15.7 16.5 17.3 18.1 18.8

[0077] Specifically, the lower the indium concentration, the larger the bandgap width of the well layer 321, and the shorter the wavelength of the generated sub-beam. In one embodiment, the first well layer 321a has a first indium concentration, and the second well layer 321b has a second indium concentration. The first indium concentration of the first well layer 321a is greater than the indium concentration of the remaining well layers 321. Further, the first indium concentration is greater than the second indium concentration, and the difference between the first indium concentration and the second indium concentration is at least 0.5%.

[0078] In another embodiment, the indium concentration in the first well layer 321a is 18% to 20%, the indium concentration in the second well layer 321b is 15% to 17%, and the indium concentration in the third well layer 321c is 12% to 14%. In this way, the spectrum of the broadband blue light generated by the light-emitting stack 32 can be closer to the curve of the standard light source (white light) in the blue light band. In one embodiment, the spectrum of the broadband blue light generated by the light-emitting stack 32 is close to the wave profile of the standard light source (white light) with a color temperature of more than 4000K in the blue light band.

[0079] For example, the first wavelength of the first sub-beam generated by the first well layer 321a may fall within the range of 455nm to 485nm. The second wavelength of the second sub-beam generated by the second well layer 321b may fall within the range of 435nm to 455nm. The third wavelength of the third sub-beam generated by the third well layer 321c may fall within the range of 425nm to 435nm.

[0080] On the other hand, since the indium concentration in the well layer 321 is related to its growth temperature, the higher the growth temperature of the well layer 321, the lower the indium concentration. Therefore, by forming the multi-layer well layer 321 at different growth temperatures, the multi-layer well layer 321 can have different bandgap widths Eg1 to Eg3.

[0081] In the embodiment of the present invention, among the multiple well layers 321 , the bandgap widths Eg1 - Eg3 of at least two well layers 321 are different, for example, the third well layer 321 c and the first well layer 321 a .

[0082] In addition, in the multi-layer well layer 321, there is at least one first well layer 321a, two second well layers 321b, and two third well layers 321c. However, the number of first well layers 321a, the number of second well layers 321b, and the number of third well layers 321c can be changed according to actual needs.

[0083] Please refer to Figure 4 , a first barrier height ΔE1 is formed between the conduction band 321E1 of the first well layer 321a and the conduction band 320E of the barrier layer 320. A second barrier height ΔE2 is formed between the conduction band 321E2 of the second well layer 321b and the conduction band 320E of the barrier layer 320. A third barrier height ΔE3 is formed between the conduction band 321E3 of the third well layer 321c and the conduction band 320E of the barrier layer 320. The third barrier height ΔE3 is smaller than the second barrier height ΔE2, and the second barrier height ΔE2 is smaller than the first barrier height ΔE1. ​​Therefore, compared with the third well layer 321c, electrons are more easily confined in the first well layer 321a, and more long-wavelength band beams (first sub-beams) are generated.

[0084] Accordingly, in one embodiment, the number of the first well layers 321a is smaller than the number of the third well layers 321c and the number of the second well layers 321b, so as to prevent the intensity of the short wavelength beam (third sub-beam) and the medium wavelength beam (second sub-beam) in the spectrum from being too low. Accordingly, the intensity of the first sub-beam is smaller than the intensity of the third sub-beam.

[0085] In addition, compared to electrons, holes have a lower mobility. Therefore, the main light-emitting region of the light-emitting stack 32 is close to the P-type semiconductor layer 31. Since electrons are more easily confined in the first well layer 321a than in the third well layer 321c, in the embodiment of the present invention, at least the well layer 321 closest to the P-type semiconductor layer 31 is the third well layer 321c, which can prevent the intensity of the long-wavelength light beam (the first sub-beam) from being too high.

[0086] That is, there is at least one other well layer between the first well layer 321a and the P-type semiconductor layer 31, such as the second well layer 321b or the third well layer 321c. In this embodiment, at least the first three well layers 321 closest to the P-type semiconductor layer 31, that is, the first three well layers 321 close to the second side 32b, are the third well layers 321c, which can prevent the intensity ratio of the short wavelength light beam (the third sub-beam) relative to the long wavelength light beam (the first sub-beam) from being too low, thereby affecting the waveform of the white light spectrum.

[0087] On the other hand, according to actual test results, if the well layer 321 closest to the N-type semiconductor layer 30 is the first well layer 321a, the intensity of the long wavelength light beam (first sub-beam) will be weaker, and it will be more difficult to increase the half-height width of the spectrum. Therefore, there is at least another well layer between the first well layer 321a and the N-type semiconductor layer 30, such as the second well layer 321b or the third well layer 321c.

[0088] In other embodiments, if the light-emitting diode has a different number of quantum wells, the position of the first well layer 321a is not limited to the second well layer close to the side (first side 32a) where the N-type semiconductor layer 30 is located. Furthermore, the position of the first well layer 321a will affect the intensity of the long wave. The closer to the N-type semiconductor layer 30, the weaker the light intensity emitted. The position may be different for different intensity requirements. However, in general, in order to allow the light-emitting diode to excite the phosphor to be close to the wavelength form of the full spectrum, the first well layer 321a is located on the side of the multiple quantum well structure that is biased towards the N-type semiconductor layer 30.

[0089] In this embodiment, the well layer 321 closest to the N-type semiconductor layer 30, that is, the well layer 321 closest to the first side 32a, is the second well layer 321b. In addition, the second well layer 321 closest to the N-type semiconductor layer 30 (the first side 32a) is the first well layer 321a. In this way, the first well layer 321a can have better light-emitting efficiency. Figure 4 In the embodiment of FIG. 5 , the third well layer 321 close to the N-type semiconductor layer 30 is the second well layer 321 b .

[0090] In addition, other well layers 321 located in the middle section of the light-emitting stack 32, that is, other well layers 321 located between the third well layer 321 close to the first side 32a (i.e., the second well layer 321b) and the third well layer 321 close to the second side 32b (i.e., the third well layer 321c), can be the third well layer 321c, the second well layer 321b or a combination thereof.

[0091] Please refer to Figure 5 , which shows the spectrum of the broadband blue light of the first embodiment of the present invention. That is to say, through the above technical means, the first sub-beam, the second sub-beam and the third sub-beam generated by the light-emitting diode M are superimposed to form the following Figure 5 Spectra shown.

[0092] like Figure 5 As shown, the waveform L5 of the broadband blue light spectrum of the present embodiment has a main peak, and the main peak has a main peak point P51. In addition, the broadband blue light spectrum of the present invention includes at least one shoulder peak on the left side (at a shorter wavelength) or the right side (at a longer wavelength) of the main peak point P51. Figure 5As shown, in the waveform L5 of the broadband blue light spectrum of the present embodiment, in addition to the main peak, there are also two shoulder peaks, which are respectively located on the left and right of the main peak point P51.

[0093] Furthermore, the light intensity of the main peak point P51 is the highest and can fall within the wavelength range of 435nm to 455nm, which is the maximum value of the light intensity. In this embodiment, the main peak point P5 is located at 449nm.

[0094] In addition, a shoulder peak is located between the wavelength corresponding to the main peak point P51 minus 5nm and 410nm. In this embodiment, the shoulder peak is located between 410nm and 444nm, and a relative maximum value or inflection point (Inflection Point) P52 appears. In this embodiment, the shoulder peak P52 is located at 437nm.

[0095] In addition, a shoulder peak is located between the wavelength corresponding to the main peak point P51 plus 10nm and 490nm. In this embodiment, the shoulder peak is located between 459nm and 490nm, and a relative maximum value or inflection point P53 appears. In the embodiment, the shoulder peak P53 is located at 466nm.

[0096] Generally speaking, a relative maximum value or inflection point P52 of the present invention falls within the wavelength range of 425nm to 435nm, and another relative maximum value or inflection point P53 falls within the wavelength range of 455nm to 485nm. The intensity corresponding to the main peak point P51 is the strongest.

[0097] In this embodiment, the intensity of the main peak point P51 is set to 100% to normalize the spectrum waveform.

[0098] In addition, the intensity corresponding to the relative maximum or inflection point P52 located on the shorter wavelength side of the main peak point P51 is greater than the intensity corresponding to the relative maximum or inflection point P53 located on the longer wavelength side of the main peak point P51. For example, the intensity corresponding to the main peak point P51 is 100%, the intensity corresponding to one relative maximum or inflection point P52 is between 10 and 60%, and the intensity corresponding to another relative maximum or inflection point P53 is between 20 and 90%. In this way, the spectrum of white light generated by the wide-band blue light passing through the wavelength conversion layer Z13 is a full spectrum.

[0099] Please refer to Figure 6 , Figure 6Schematic diagram of the bandgap structure of the light-emitting stack of the second embodiment of the present invention. In this embodiment, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the third well layer 321c, and the second or third well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the second well layer 321b. In this way, the third well layer 321c can have better light-emitting efficiency. Figure 6 In the embodiment of the present invention, the second well layer 321 close to the N-type semiconductor layer 30 is the second well layer 321 b , and the third well layer 321 close to the N-type semiconductor layer 30 is the first well layer 321 a .

[0100] In addition, the well layer 321 closest to the P-type semiconductor layer (the second side 32a) is the third well layer 321c, and the other well layers 321 located in the middle section of the light-emitting stack 32, that is, the other well layers 321 located between the third well layer 321 close to the first side 32a (i.e., the first well layer 321a) and the third well layer 321 close to the second side 32b (i.e., the third well layer 321c), can be the third well layer 321c, the second well layer 321b or a combination thereof, which is not limited by the present invention.

[0101] Please refer to Figure 7 . Figure 7 FIG. 1 is a schematic diagram of the bandgap structure of the light-emitting stack according to the third embodiment of the present invention. Figure 7 As shown, the difference between this embodiment and the first embodiment is that the multiple barrier layers 320' can have different thicknesses. Further, the multiple barrier layers 320' include at least two first barrier layers 320a and at least one second barrier layer 320b ( Figure 7 (a plurality is shown).

[0102] The two first barrier layers 320a are located on opposite sides of one of the first well layers 321a. In other words, one of the first well layers 321a is sandwiched between the two first barrier layers 320a. In detail, the second well layer 321 closer to the N-type semiconductor layer 30 is the first well layer 321a, and the first well layer 321a (i.e., the second well layer 321 closer to the N-type semiconductor layer 30) is sandwiched between the two first barrier layers 320a.

[0103] The thickness T1 of each first barrier layer 320a is greater than the thickness T2 of the second barrier layer 320b. Further, in one embodiment, the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b. Preferably, the thickness T1 of the first barrier layer 320a is 1.2 to 1.5 times the thickness T2 of the second barrier layer 320b.

[0104] From another perspective, the difference between the thickness T1 of the first barrier layer 320a and the thickness T2 of the second barrier layer 320b is at least 5%. That is, assuming that the difference D between the thickness T1 of the first barrier layer 320a and the thickness T2 of the second barrier layer 320b is T1-T2, then (D / T1)*100% is at least 5%.

[0105] Accordingly, only the thickness of the two first barrier layers 320a connected to the first well layer 321a is 2.5 to 5 times the thickness of the well layer 321, while the thickness of the other second barrier layers 320b is still 2 to 3.5 times the thickness of the well layer 321. In other words, it is not necessary to increase the thickness of each barrier layer 320 to 2.5 to 5 times the thickness of the well layer, but only to increase the thickness of the two first barrier layers 320a connected to the first well layer 321a. Compared with the prior art, this embodiment can reduce the influence of the change of the operating current on the spectrum shape generated by the light-emitting stack 32.

[0106] In another embodiment, the plurality of second barrier layers 320b may also have different thicknesses. Further, the thickness of the second barrier layer 320b adjacent to one of the third well layers 321c is different from the thickness of the second barrier layer 320b adjacent to one of the second well layers 321b. Further, the thickness of the second barrier layer 320b adjacent to one of the third well layers 321c may be less than the thickness of the second barrier layer 320b adjacent to one of the second well layers 321b.

[0107] In addition, the other well layer 321 located in the middle section of the light-emitting stack 32, that is, the other well layer 321 located between the second well layer 321 close to the first side 32a (i.e., the first well layer 321a) and the third well layer 321 close to the second side 32b (i.e., the third well layer 321c), can be the third well layer 321c, the second well layer 321b or a combination thereof, which is not limited in the present invention. Figure 7 In the embodiment of FIG. 1 , the other well layers 321 located in the middle section of the light-emitting stack 32 are all second well layers 321 b .

[0108] It is worth mentioning that the light emitting diode M of this embodiment operates at 100mA / mm 2 Up to 300mA / mm 2 When the first light intensity of the first sub-beam is less than the second light intensity of the second sub-beam, the first light intensity of the first sub-beam is less than the second light intensity of the second sub-beam. In other words, the ratio of the first light intensity to the second light intensity is between 0.1 and 0.9.

[0109] Please refer to Figure 8 , Figure 8 Spectrum of broadband blue light of the light emitting diode according to the third embodiment of the present invention. Figure 8 The spectrum of broadband blue light is Figure 5The difference is that the spectrum waveform L8 of the broadband blue light spectrum includes a main peak and a shoulder peak located on the right side of the main peak (at a longer wavelength). The spectrum waveform L8 includes a main peak point P81 and an inflection point P82 (or a relative maximum value) located on the right side of the main peak point P81.

[0110] The main peak point P81 falls within the wavelength range of 430nm to 455nm and has the maximum intensity. In the actual embodiment, P81 is located at 442nm. The inflection point (or relative maximum value) P82 is the inflection point that appears at 490nm after adding 10nm to the wavelength of the main peak point P81. In the actual embodiment, the inflection point P82 falls within the wavelength range of 455nm to 475nm. In addition, the difference between the wavelengths corresponding to the main peak point P81 and the inflection point (or relative maximum value) P82 is between 10 and 30nm.

[0111] As mentioned above, the intensity corresponding to the main peak point P81 is greater than the intensity corresponding to the inflection point (or relative maximum value) P82. In this embodiment, the intensity corresponding to the main peak point P81 is set to 100% to normalize the spectral waveform L8. Thus, the intensity corresponding to the inflection point (or relative maximum value) P82 is between 20 and 90%. Figure 8 In the embodiment of FIG. 1 , the intensity corresponding to the inflection point (or relative maximum value) P82 is between 70% and 90%. Thus, the spectrum of the white light generated by the broadband blue light passing through the wavelength conversion layer Z13 is the full spectrum.

[0112] It is worth mentioning that the size of the bandgap width Eg1 of the first well layer 321a will affect the half-height width of the broadband blue light spectrum waveform. Further, in the broadband blue light spectrum, the bandgap width Eg1 of the first well layer 321a will affect the relative position between the peak point located at the main peak and the peak point of the shoulder peak located to the right thereof. That is to say, in the broadband blue light spectrum generated by the light-emitting stack 32, as the bandgap width Eg1 of the first well layer 321a decreases, the peak point of the shoulder peak located to the right of the main peak (e.g. Figure 8 The inflection point P82 in the figure will be relative to the peak point of the main peak (for example Figure 8 The main peak point P81 in the spectrum shifts toward the long wavelength direction.

[0113] Please refer to Fig. 9 , Fig. 9 The diagram shows the wide-band blue light spectrum generated by the light-emitting diodes of different embodiments of the present invention before packaging, that is, the spectrum measured by point measurement before the light-emitting diodes M are packaged.

[0114] exist Fig. 9 In Figure 7The wide-band blue light spectrum generated by the light-emitting stack 32 is used as an example. Fig. 9 The three waveforms L91, L92, and L93 of the three wide-band blue light spectra correspond to three different light-emitting stacks 32. The arrangement order of the multiple barrier layers 320' and the multiple well layers 321 of the three light-emitting stacks 32 is the same as Figure 7 The embodiment is the same as that of the embodiment, but the bandgap widths Eg1 of the first well layers 321a of the three light-emitting stacks 32 are different.

[0115] Waveform L91 represents that the bandgap width Eg1 of the first well layer 321a of the light-emitting stack 32 is the widest, waveform L92 represents that the bandgap width Eg1 of the first well layer 321a of the light-emitting stack 32 is the second widest, and waveform L93 represents that the bandgap width Eg1 of the first well layer 321a of the light-emitting stack 32 is the smallest.

[0116] like Fig. 9 As shown, waveforms L91, L92, and L93 all have a main peak and a shoulder peak located on the right side of the main peak. It should be noted that waveforms L91, L92, and L93 are formed by superimposing the first sub-beam, the second sub-beam, and the third sub-beam generated by the light-emitting stack 32. The main peak of each waveform L91, L92, or L93 may correspond to the second sub-beam generated by the second well layer 321b, and the shoulder peak located on the right side of the main peak may correspond to the first sub-beam generated by the first well layer 321a.

[0117] Each of the main peaks of waveforms L91, L92, and L93 has a main peak point P911, P921, and P931. In this embodiment, when the waveform L91 is standardized, the intensity of the main peak point P911 of the waveform L91 is set to 100%. Similarly, when the waveforms L92 and L93 are standardized, the intensity of the main peak point P921 of the waveform L92 is set to 100%. And the intensity of the main peak point P931 of the waveform L93 is set to 100%.

[0118] Depend on Fig. 9 It can be seen that the main peaks of the waveforms L91, L92, and L93 are roughly overlapped, and the main peak points P911, P921, and P931 of the three main peaks are roughly the same. However, due to the difference in the bandgap width Eg1 of the first well layer 321a, the difference between the wavelength corresponding to the peak point P932 of the shoulder peak of the waveform L93 (about 467nm) and the wavelength corresponding to the main peak point P931 of the main peak (about 445nm) is greater than the difference between the wavelength corresponding to the peak point P922 of the shoulder peak (about 463nm) and the wavelength corresponding to the main peak point P921 of the main peak (about 445nm) in the other waveform L92.

[0119] Similarly, in the waveform L92, the difference between the wavelength corresponding to the peak point P922 of the shoulder peak (about 463nm) and the wavelength corresponding to the main peak point P921 of the main peak (about 445nm) is greater than the difference between the wavelength corresponding to the peak point P912 of the shoulder peak (about 460nm) and the wavelength corresponding to the main peak point P911 of the main peak (about 445nm) in the other waveform L91. In other words, the smaller the bandgap width Eg1 of the first well layer 321a, the farther the peak point of the shoulder peak is from the peak point of the main peak in the wide-band blue light spectrum.

[0120] Please refer to Fig.10 , Fig.10 Spectra of broadband blue light of a light emitting diode under different operating currents according to an embodiment of the present invention. Fig.10 The light emitting stack 32 of the light emitting diode has Figure 7 The bandgap structure shown.

[0121] Curve L101 and curve L102 represent the spectral waveforms generated by the light emitting diode operating at 25° C. However, curve L101 represents the light emitting diode operating at a driving current of 60 mA (operating current density of 120 mA / mm 2 ), and curve L102 represents the spectrum waveform of the light emitting diode operating at a driving current of 150 mA (operating current density of 300 mA / mm 2 ) under the spectral waveform.

[0122] It should be noted that since the chip sizes of the LEDs used for testing are the same, it can be seen that curve L101 is the spectral waveform measured by the LED at a lower operating current density, and curve L102 represents the spectral waveform measured by the LED at a higher operating current density.

[0123] Furthermore, in this embodiment, the chip size of the LED is 26×30mil 2 Therefore, curve L101 is the light emitting diode at an operating current density of 120mA / mm 2 The measured spectrum waveform, and curve L102 is the light emitting diode at an operating current density of 300mA / mm 2 The measured spectral waveform.

[0124] like Fig.10As shown, the spectral waveform L101 and the spectral waveform L102 each have a main peak in the medium wavelength range (about 435nm to 445nm), and have main peak points P1011 and P1021 respectively. In the long wavelength range (about 450nm to 460nm), the spectral waveform L101 and the spectral waveform L102 also each have a shoulder peak, and have a relative maximum or inflection point P1012 and P1022 respectively. In this embodiment, when standardizing the spectral waveform L101, the intensity of the main peak point P1011 of the spectral waveform L101 is set to 100%, and the intensity of the main peak point P1021 of the spectral waveform L102 is set to 100%.

[0125] Furthermore, in this embodiment, the main peaks of the spectral waveforms L101 and L102 correspond to the second sub-beam generated by the second well layer 321 b , and the shoulder peaks on the right side of the main peaks correspond to the first sub-beam generated by the first well layer 321 a .

[0126] Depend on Fig.10 It can be seen that the half-height width of the spectrum waveform L101 is greater than the half-height width of the spectrum waveform L102. That is to say, in this embodiment, the half-height width of the spectrum waveform of the light beam generated by the light-emitting diode will increase as the driving current (or operating current density) decreases. Moreover, as the operating current density decreases, the spectrum waveform emitted by the chip of the light-emitting diode in this embodiment will move toward the long wavelength side, and there will be a red shift phenomenon.

[0127] In addition, the intensity corresponding to the relative maximum value or inflection point P1012 of the spectrum waveform L101 is greater than the intensity corresponding to the relative maximum value or inflection point P1022 of the spectrum waveform L102. In other words, when the driving current (or operating current density) increases, the relative intensity of the first sub-beam with a longer wavelength generated by the first well layer 321a will be lower.

[0128] Accordingly, in the embodiment of the present invention, when the operating current density of the light emitting diode is 100 mA / mm 2 Up to 300mA / mm 2 When the operating current density varies between 0.1 and 0.9, the ratio of the first light intensity of the first sub-beam to the second light intensity of the second sub-beam varies between 0.1 and 0.9 as the operating current density varies.

[0129] Please refer to Fig.11 , Fig.11 Spectra of broadband blue light of a light emitting diode under different operating temperatures according to an embodiment of the present invention. Fig.11 The light emitting stack 32 of the light emitting diode has Figure 7 The bandgap structure shown.

[0130] Curve L111 and curve L112 are both spectral waveforms of a light emitting diode operating at a driving current of 60 mA, but the operating temperature of curve L111 is 25° C., while the operating temperature of curve L112 is 85° C.

[0131] like Fig.11 As shown, the spectral waveform L111 and the spectral waveform L112 each have a main peak in the medium wavelength range (about 440nm to 450nm), and have main peak points P1111 and P1121 respectively. In the long wavelength range (about 450nm to 460nm), the spectral waveform L111 and the spectral waveform L112 also each have a shoulder peak, and have a relative maximum or inflection point P1112 and P1122 respectively. In this embodiment, when standardizing the spectral waveform L111, the intensity of the main peak point P1111 of the spectral waveform L111 is set to 100%, and the intensity of the main peak point P1121 of the spectral waveform L112 is set to 100%.

[0132] Furthermore, in this embodiment, the main peaks of the spectral waveforms L111 and L112 correspond to the second sub-beam generated by the second well layer 321 b , and the shoulder peaks on the right side of the main peaks correspond to the first sub-beam generated by the first well layer 321 a .

[0133] Depend on Fig.11 It can be seen that the half-maximum width of the spectrum waveform L112 is greater than the half-maximum width of the spectrum waveform L111. That is, when the same driving current is applied, the half-maximum width of the spectrum waveform of the light beam of the light emitting diode of this embodiment increases with the increase of operating temperature.

[0134] In addition, the intensity corresponding to the relative maximum value or inflection point P1112 of the spectrum waveform L112 is greater than the intensity corresponding to the relative maximum value or inflection point P1122 of the spectrum waveform L111. That is, when the operating temperature increases, the relative intensity of the first sub-beam with a longer wavelength generated by the first well layer 321a is higher.

[0135] Accordingly, in the embodiment of the present invention, when the operating temperature of the LED is between 25° C. and 85° C., the ratio of the first light intensity of the first sub-beam to the second light intensity of the second sub-beam varies between 0.1 and 0.9 as the operating temperature changes.

[0136] Please refer to Fig.12 , Fig.12 Schematic diagram of the bandgap structure of the light-emitting stack according to the fourth embodiment of the present invention. Figure 7 The same elements of the embodiments have the same reference numerals.

[0137] Similar to the third embodiment, in this embodiment, the plurality of barrier layers 320′ include at least two first barrier layers 320a and at least one second barrier layer 320b ( Fig.12 The two first barrier layers 320a are located at opposite sides of one of the first well layers 321a. That is, one of the first well layers 321a is sandwiched between the two first barrier layers 320a. The thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.

[0138] In addition, Fig.12 In the embodiment, the well layer 321 closest to the P-type semiconductor layer 31 (the second side 32b) is the third well layer 321c, but the second and third well layers 321 closest to the P-type semiconductor layer 31 are both the second well layer 321b.

[0139] Please refer to Fig.13 , Fig.13 Schematic diagram of the bandgap structure of the light-emitting stack of the fifth embodiment of the present invention. Figure 7 The same elements of the embodiments have the same reference numerals.

[0140] Compared to Figure 7 In the third embodiment, in this embodiment, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a, and the well layer 321 second closest to the N-type semiconductor layer 30 is the second well layer 321b. In another embodiment, the well layer 321 closest to the first side 32a and the second closest to the first side 32a are both the second well layer 321b, and the well layer 321 third closest to the first side 32a is the first well layer 321a.

[0141] In other words, refer to Figure 7 , Fig.12 as well as Fig.13 In the embodiment, at least one of the first three well layers 321 closest to the N-type semiconductor layer 30 is the first well layer 321 a.

[0142] In addition, in this embodiment, the plurality of barrier layers 320' also include at least two first barrier layers 320a and at least one second barrier layer 320b ( Fig.11 A plurality of layers are shown.) The thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.

[0143] In this embodiment, at least one first barrier layer 320a is connected between two second well layers 321b. In addition, among the plurality of well layers 321, there is only one first well layer 321a, and one second barrier layer 320b is located between the first well layer 321a and the second well layer 321b.

[0144] Please refer to Fig.14 , Fig.14 Schematic diagram of the bandgap structure of the light-emitting stack according to the sixth embodiment of the present invention. Figure 7 The same elements of the embodiments have the same reference numerals.

[0145] Similar to the third embodiment, in this embodiment, the plurality of barrier layers 320' include at least two first barrier layers 320a and at least one second barrier layer 320b ( Fig.14 The two first barrier layers 320a are located at opposite sides of one of the first well layers 321a. That is, one of the first well layers 321a is sandwiched between the two first barrier layers 320a. The thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.

[0146] Furthermore, the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b. Preferably, the thickness T1 of the first barrier layer 320a is 1.2 to 1.5 times the thickness T2 of the second barrier layer 320b.

[0147] Only the thickness of the two first barrier layers 320a connected to the first well layer 321a is 2.5 to 5 times the thickness of the well layer 321, while the thickness of the other second barrier layers 320b is still 2 to 3.5 times the thickness of the well layer 321. In other words, it is not necessary to increase the thickness of each barrier layer 320 to 2.5 to 5 times the thickness of the well layer, but only the thickness of the two first barrier layers 320a connected to the first well layer 321a needs to be increased, which can reduce the influence of the change of the operating current on the spectrum shape generated by the light-emitting stack 32 compared with the prior art.

[0148] In addition, Fig.14 In the embodiment of the present invention, the first six well layers 321 closest to the second side 32b (ie, the side close to the P-type semiconductor layer 31) are the third well layers 321c.

[0149] Please refer to Fig.15 , which is a schematic diagram of the bandgap structure of the light-emitting stack according to the seventh embodiment of the present invention. The number and arrangement of the first well layer 321a, the second well layer 321b and the third well layer 321c of this embodiment are similar to Figure 7 That is, the number of the second well layers 321 b in this embodiment is greater than the number of the first well layers 321 a and greater than the number of the third well layers 321 c .

[0150] In addition, in this embodiment, except that the first three well layers 321 closest to the second side 32b (that is, the side close to the P-type semiconductor layer 31) are the third well layer 321c, and the second well layer 321 close to the first side 32a (that is, the side close to the N-type semiconductor layer 30) is the first well layer 321a, the other well layers 321 located in the middle of the light-emitting stack 32 are all second well layers 321b. In this embodiment, the well layers 321 located in the middle of the light-emitting stack 32 are all second well layers 321b, which can improve mass production stability.

[0151] This embodiment and Figure 7 (Third Embodiment) The difference is that the plurality of barrier layers 320 of this embodiment have the same thickness.

[0152] In addition, it should be noted that in the embodiment of the present invention, the number of the first well layer 321a is only one, but the present invention is not limited thereto. In other embodiments, the number of the first well layer 321a can also be multiple, as long as the well layer 321 located at the second or third position close to the N-type semiconductor layer 32a is the first well layer 321a, and the intensity of the first sub-beam does not affect the white light spectrum, the present invention does not limit the number of the first well layer 321a.

[0153] Please refer to Fig.16 , Fig.16 Schematic diagram of the bandgap structure of the light-emitting stack according to the eighth embodiment of the present invention. In this embodiment, the plurality of barrier layers 320' include at least two first barrier layers 320a and at least one second barrier layer 320b ( Fig.16 A plurality of layers are shown.) The thickness T1 of the first barrier layer 320a is greater than the thickness T2 of the second barrier layer 320b.

[0154] Further, the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b. Preferably, the thickness T1 of the first barrier layer 320a is 1.2 to 1.5 times the thickness T2 of the second barrier layer 320b. The thickness T1 of the first barrier layer 320a is 2.5 to 5 times the thickness of the well layer 321, while the thickness T2 of the other second barrier layer 320b is still 2 to 3.5 times the thickness of the well layer 321.

[0155] This embodiment and Figure 7 The embodiment (third embodiment) is different in that at least one of the two barrier layers 320' connected to the second well layer 321b is a first barrier layer 320a. In this embodiment, at least two first barrier layers 320a are located on opposite sides of one of the second well layers 321b. In other words, one of the second well layers 321a is sandwiched between two first barrier layers 320a. The thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.

[0156] It is worth mentioning that if the two barrier layers 320' connected to the second well layer 321b are both the thicker first barrier layer 320a, in the broadband blue light spectrum, the intensity ratio of the long wavelength range (about 460nm to 480nm) and the medium wavelength range (about 440nm to 450nm) will also change accordingly.

[0157] For further information, please refer to Fig.17 , is the spectrum of the broadband blue light of the light emitting diodes of the seventh and eighth embodiments of the present invention. Fig.17 In FIG. 1 , curve L171 represents the spectrum waveform of the light emitting diode of the seventh embodiment of the present invention, and curve L172 represents the spectrum waveform of the light emitting diode of the eighth embodiment of the present invention. It should be noted that in the seventh embodiment (such as Fig.15 ), the thickness of all barrier layers 320 are the same.

[0158] The spectral waveform L171 of the seventh embodiment and the spectral waveform L172 of the eighth embodiment both have a main peak in the middle wavelength range (about 440nm to 450nm) and a shoulder peak in the long wavelength range (about 460nm to 480nm).

[0159] The main peak of the spectrum waveform L171 of the seventh embodiment has a main peak point P1711, and the main peak of the spectrum waveform L172 of the eighth embodiment also has a main peak point P1721. In addition, the shoulder peak of the spectrum waveform L171 of the seventh embodiment in the long wavelength range (about 460nm to 480nm) has a relative maximum value or inflection point P1712. The shoulder peak of the spectrum waveform L172 of the eighth embodiment in the long wavelength range (about 460nm to 480nm) has a relative maximum value or inflection point P1722.

[0160] In this embodiment, when the spectrum waveform of the light emitting diode of the seventh embodiment is standardized, the intensity of the main peak point P1711 of the spectrum waveform L171 is set to 100%. In addition, when the spectrum waveform of the light emitting diode of the eighth embodiment is standardized, the intensity of the main peak point P1721 of the spectrum waveform L172 is set to 100%.

[0161] like Fig.17As shown, if the barrier layers 320 on both sides of the second well layer 321b are replaced with the first barrier layers 320a with a relatively thick thickness, the intensity corresponding to the relative maximum value or inflection point P1722 of the spectrum waveform L172 will be lower than the intensity corresponding to the relative maximum value or inflection point P1712 of the spectrum waveform L171. In other words, when the thickness of the barrier layers 320' on both sides of the second well layer 321b is relatively thick, the intensity in the long wavelength range of the spectrum of the light beam generated by the light-emitting stack 32 will be relatively weak. Therefore, by changing the thickness of multiple barrier layers 320', the spectrum waveform of the light beam can also be adjusted.

[0162] Please refer to Fig.18 , Fig.18 FIG. 3 is a schematic diagram of the bandgap structure of the light-emitting stack of the ninth embodiment of the present invention. In this embodiment, the barrier layer 320 is a gallium nitride (GaN) layer, and the material of the well layer 321 includes indium gallium nitride, which can be expressed as InGaN. x Ga (1-x) N, where x is between 0.12 and 0.2. As mentioned above, the indium concentration in the well layer 321 affects the bandgap width of the well layer 321, so the bandgap width of the well layer 321 can be adjusted by controlling the indium concentration in each well layer, thereby controlling the emission wavelength of the well layer 321.

[0163] In this embodiment, the plurality of well layers 321a to 321i have different indium concentrations, and the indium concentration of the well layer (e.g., the first well layer 321a) closer to the N-type semiconductor layer 30 (the first side 32a) is greater than the indium concentration of the well layer (e.g., the first well layer 321i) farther from the N-type semiconductor layer 30 (the first side 32a). The difference between the indium concentration of each well layer (e.g., the well layer 321a) and the indium concentration of the adjacent well layer (e.g., the well layer 321b) is at least 0.5%, so that the indium concentration in the multiple quantum well structure of the light-emitting stack 32 forms a gradient.

[0164] Refer to Table 2 below and Fig.18 , showing the indium concentration (%) of the multiple well layers 321a~321i in this embodiment and the wavelengths of the multiple sub-beams generated therefrom.

[0165] Table 2

[0166] Well layer 321a 321b 321c 321d 321e 321f 321g 321h 321i Wavelength (nm) 464 458 452 446 440 434 428 422 416 Indium concentration (%) 18 17 16 15 14 13 12 11 10

[0167] The lower the indium concentration, the larger the bandgap width of the well layers 321a-321i, and the shorter the wavelength of the generated light beam. It can be seen from the above table that in the light-emitting stack 32 of the present embodiment, the indium concentration of the plurality of well layers 321a-321i decreases from the N-type semiconductor layer 30 (first side 32a) toward the P-type semiconductor layer 31 (second side 32b).

[0168] Since the indium concentration in the well layers 321a to 321i is related to their growth temperature. When the growth temperature of the well layers 321a to 321i is higher, the indium concentration is lower. Therefore, by forming the multi-layer well layers 321a to 321i at different growth temperatures, the multi-layer wells 321a to 321i can have different bandgap widths Eg1 to Eg9. In this embodiment, the bandgap widths of the multiple well layers 321a to 321i increase from the first side 32a toward the second side 32b. In this way, the difference between the wavelength of the sub-beam generated by each well layer (such as the well layer 321a) and the wavelength of the sub-beam generated by its most adjacent well layer (such as the well layer 321b) is at least 1nm, and the well layer closest to the P-type semiconductor layer 31 (such as the well layer 321i) is used to generate a sub-beam with the shortest wavelength.

[0169] Based on the above, the light beam after the plurality of sub-beams generated by the plurality of well layers 321 a - 321 i are mixed will also have a broadband blue light spectrum.

[0170] Please refer to Fig.19 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the tenth embodiment of the present invention. In this embodiment, the indium concentration of the well layer 321 (e.g., the first well layer 321a) closest to the N-type semiconductor layer 30 (the first side 32a) is greater than the well layer 321 (e.g., the fifth well layer 321e) farthest from the N-type semiconductor layer 30 (the first side 32a). Therefore, the bandgap width Eg1 of the well layer 321a closest to the first side 32a will be the smallest, and the bandgap width Eg5 of the well layer 321e farthest from the first side 32a (that is, closest to the second side 32b) will be the widest.

[0171] Further, in the multiple well layers 321 of the present embodiment, the first well layer 321a closest to the first side 32a has a first indium concentration, the second and third second well layers 321b close to the first side 32a have the same second indium concentration, and the fourth and fifth third well layers 321c close to the first side 32a have the same third indium concentration. The sixth and seventh fourth well layers 321d close to the first side 32a have the same fourth indium concentration, and the two fifth well layers 321e close to the second side 32b have the same fifth indium concentration. The first to fifth indium concentrations of the first to fifth well layers 321a to 321e are gradually decreasing.

[0172] In one embodiment, the difference between the first and second indium concentrations, the difference between the second and third indium concentrations, the difference between the third and fourth indium concentrations, and the difference between the fourth and fifth indium concentrations are all at least 0.5%.

[0173] Compared to Fig.18As for the ninth embodiment, in the light emitting stack 32 of this embodiment, at least two well layers 321 (such as two second well layers 321b) have the same indium concentration. However, the light beam after mixing the multiple sub-beams generated by the multiple well layers 321 will also have a wide-band blue light spectrum.

[0174] Please refer to Fig. 20 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the eleventh embodiment of the present invention. In this embodiment, the indium concentration of the well layer 321 (e.g., the first well layer 321a) closest to the N-type semiconductor layer 30 (the first side 32a) is greater than the well layer 321 (e.g., the fourth well layer 321d) farthest from the N-type semiconductor layer 30 (the first side 32a). Therefore, the bandgap width Eg1 of the well layer 321a closest to the first side 32a will be the smallest, and the bandgap width Eg4 of the well layer 321d farthest from the first side 32a (that is, closest to the second side 32b) will be the widest.

[0175] Further, in the multiple well layers 321 of the present embodiment, the first well layer 321a closest to the first side 32a has a first indium concentration, the second and third second well layers 321b close to the first side 32a have the same second indium concentration, and the third well layers 321c close to the first side 32a from the fourth to the sixth have the same third indium concentration. The third well layers 321d close to the first side 32a from the seventh to the ninth have the same fourth indium concentration, wherein the first to fourth indium concentrations are gradually decreasing.

[0176] In one embodiment, the difference between the first and second indium concentrations, the difference between the second and third indium concentrations, and the difference between the third and fourth indium concentrations are all at least 0.5%.

[0177] Compared to Fig.18 For the ninth embodiment, in the eleventh embodiment, at least three well layers 321 (e.g., three third well layers 321c and three fourth well layers 321d) have the same indium concentration in the light emitting stack 32. The light beam after mixing the multiple sub-beams generated by the multiple well layers 321 will also have a wide-band blue light spectrum.

[0178] Please refer to Fig.21 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the twelfth embodiment of the present invention. In the light-emitting stack 32 of this embodiment, the multiple well layers 321 include a first well layer 321a, a second well layer 321b and a third well layer 321c, the bandgap width Eg3 of the third well layer 321c is greater than the bandgap width Eg2 of the second well layer 321b, and the bandgap width Eg2 of the second well layer 321b is greater than the bandgap width Eg1 of the first well layer 321a.

[0179] In this embodiment, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the second well layer 321b, and the second well layer 321 closest to the first side 32a is the first well layer 321a. In addition, the first three well layers 321 closest to the P-type semiconductor layer 31 (second side 32b) are all third well layers 321c.

[0180] In this embodiment, the first well layer 321a is used to generate a first sub-beam with a first wavelength, the second well layer 321b is used to generate a second sub-beam with a second wavelength, and the third well layer 321c is used to generate a third sub-beam with a third wavelength. By adjusting the forbidden band widths Eg1, Eg2, and Eg3 of the first to third well layers 321a to 321c, the first wavelength, the second wavelength, and the third wavelength can be adjusted.

[0181] Specifically, in one embodiment, the first wavelength is between 470 nm and 490 nm, the second wavelength is between 435 nm and 455 nm, and the third wavelength is between 425 nm and 450 nm.

[0182] In addition, the second well layers 321b have the largest number, and the second light intensity of the second sub-beam generated by the second well layers 321b is greater than the first light intensity of the first sub-beam generated by the first well layers 321a, and greater than the third light intensity of the third sub-beam generated by the third well layers 321c.

[0183] Please refer to Fig. 22 , which is the spectrum of the broadband blue light of the light emitting diode of the twelfth embodiment of the present invention before and after packaging. The bandgap structure of the light emitting stack 32 of the light emitting diode of the twelfth embodiment of the present invention can be referred to Fig.21 .exist Fig. 22 In the figure, curve L221 is the waveform of the wide-band blue light spectrum before the LED is packaged, and curve L222 is the waveform of the wide-band blue light spectrum after the LED is packaged.

[0184] like Fig. 22 As shown, no matter before or after packaging, the spectrum waveforms L221 and L222 have a main peak and a shoulder peak located on the right side of the main peak.

[0185] The main peak points P2211 and P2221 of the spectral waveforms L221 and L222 both fall within the wavelength range of 435nm to 455nm and correspond to the maximum light intensity. In this embodiment, the intensity of the main peak point P2211 is set to 100% to normalize the spectral waveform L221. In addition, the intensity of the main peak point P2221 is set to 100% to normalize the spectral waveform L222. It is worth noting that the wavelength corresponding to the main peak points P2211 and P2221 is the second wavelength of the second sub-beam.

[0186] In this embodiment, the first sub-beam generated by the first well layer 321a will cause the spectral waveforms L221 and L222 to have shoulder peaks located on the right side of the main peak points P2211 and P2221, and the spectral waveforms L221 and L222 will have relative maximum values ​​or inflection points P2212 and P2222 between the wavelengths corresponding to the main peak points P2211 and P2221 plus 10nm to 490nm.

[0187] Please refer to Fig.23 , which is a schematic diagram of the forbidden band structure of the light-emitting stack of the thirteenth embodiment of the present invention. In this embodiment, the plurality of well layers 321 ( Fig.23 The first to fifth well layers 321a to 321e have a bandgap width Eg1 to Eg5 from small to large to generate first to fifth sub-beams with different wavelengths.

[0188] Further, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the second well layer 32b, and the well layer 321 second closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a. The third to sixth well layers 321 close to the N-type semiconductor layer 30 (first side 32a) are all third well layers 321c, and the seventh to ninth well layers 321 close to the N-type semiconductor layer 30 (first side 32a) are all fourth well layers 321d. In addition, the well layers 321 closest to and second closest to the P-type semiconductor layer 31 (second side 32b) are all fifth well layers 321e.

[0189] In addition, in the present embodiment, the plurality of barrier layers 320' includes at least a plurality of first barrier layers 320a and a plurality of second barrier layers 320b, and the thickness T1 of each first barrier layer 320a is greater than the thickness T2 of the second barrier layer 320b. Further, in one embodiment, the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b, and preferably, the thickness T1 of the first barrier layer 320a is 1.2 to 1.5 times the thickness T2 of the second barrier layer 320b.

[0190] In this embodiment, the first three barrier layers 320' closest to the N-type semiconductor layer 30 (first side 32a) are all first barrier layers 320a with a relatively thick thickness, and the other barrier layers 320' are all second barrier layers 320b. In other words, the barrier layers 320' on both sides of the first well layer 321a and the second well layer 321b are all first barrier layers 320a.

[0191] In general, in this embodiment, the first and second well layers 321a and 321b each have only one layer, the third well layer 321c has four layers, the fourth well layer 321d has three layers, and the fifth well layer 321e has two layers. Since the third well layer 321c has the largest number, the third sub-beam generated by the third well layer 321c has the largest light intensity.

[0192] Although the first well layer 321a and the second well layer 321b each have only one layer, the first barrier height ΔE1 formed between the first well layer 321a and the barrier layer 320', and the second barrier height ΔE2 formed between the second well layer 321b and the barrier layer 320' are relatively high, and the barrier layers 320' located on both sides of the first well layer 321a and the second well layer 321b are both thicker first barrier layers 320a, which are easier to confine electrons. Therefore, the first sub-beam generated by the first well layer 321a and the second sub-beam generated by the second well layer 321b will also have a certain light intensity, so that the wide-band blue light spectrum generated by the light-emitting stack 32 has a larger half-height width or has more than two peaks.

[0193] Please refer to Fig.24 , which is the spectrum of the broadband blue light of the light emitting diode of the thirteenth embodiment of the present invention. The first to fifth sub-beams generated by the light emitting diode are superimposed to form the following Fig.24 Spectra shown.

[0194] like Fig.24 As shown, the waveform L24 of the broadband blue light spectrum of this embodiment has a main peak, and the main peak has a main peak point P241. In this embodiment, the intensity of the main peak point P241 is set to 100% to normalize the spectrum waveform.

[0195] like Fig.24 As shown, the light intensity of the main peak point P241 is the highest and falls within the wavelength range of 430nm to 450nm, which is the maximum value of the light intensity. In this embodiment, the wavelength corresponding to the main peak point P241 corresponds to the third wavelength of the third sub-beam. That is, by changing the bandgap width Eg3 of the third well layer 321c, the wavelength corresponding to the main peak point P241 can be adjusted.

[0196] In addition, the broadband blue light spectrum of the present invention includes two shoulder peaks on the right side (at a longer wavelength) of the main peak point P241. Specifically, the shoulder peak located on the right side of the main peak point P241 and closest to the main peak point P241 has a relative maximum value P242 (i.e., shoulder peak value), and the relative maximum value P242 falls within the wavelength range of 460nm to 480nm.

[0197] The wavelength corresponding to the relative maximum value P242 is also related to the bandgap width Eg2 of the second well layer 321b. Accordingly, by adjusting the bandgap width Eg2 of the second well layer 321b, the difference between the wavelength corresponding to the relative maximum value P242 and the wavelength corresponding to the main peak point P241 can be adjusted.

[0198] In addition, the shoulder peak located on the right side of the main peak point P241 and the second closest to the main peak point P241 causes the spectrum waveform L241 to have another relative maximum value P243 between the wavelengths of 480nm and 500nm. Similarly, the wavelength corresponding to the relative maximum value P243 is related to the bandgap width Eg1 of the first well layer 321a. Accordingly, by adjusting the bandgap width Eg1 of the first well layer 321a, the difference between the wavelength corresponding to the relative maximum value P243 and the wavelength corresponding to the main peak point P241 can be adjusted.

[0199] In one embodiment, the difference between the fourth wavelength of the fourth sub-beam generated by the fourth well layer 321d and the third wavelength of the third sub-beam generated by the third well layer 321c is less than 15nm. In addition, the difference between the fifth wavelength of the fifth sub-beam generated by the fifth well layer 321e and the fourth wavelength is less than 10nm. Fig.24 In the spectral waveform L24 shown, the third sub-beam, the fourth sub-beam and the fifth sub-beam overlap with each other so that the main peak has a wider waveform.

[0200] Please refer to Fig.25 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the fourteenth embodiment of the present invention. Fig.23The difference of the thirteenth embodiment shown is that, in this embodiment, the positions of the first well layer 321a and the second well layer 321b are interchanged. That is, in this embodiment, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a, and the well layer 321 second closest to the N-type semiconductor layer 30 (first side 32a) is the second well layer 321b. That is, even if the positions of the first well layer 321a and the second well layer 321b are interchanged, the following can be generated. Fig.24 The wide-band blue light spectrum shown in FIG. 1 also has a large half-width and multiple peaks (including a main peak and two shoulder peaks located on the right side of the main peak).

[0201] In addition, the number of the third well layers 321c, the number of the fourth well layers 321d, and the number of the fifth well layers 321e do not have to be the same, but can be adjusted according to actual needs. Fig.26 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the fifteenth embodiment of the present invention. Fig.23 The difference of the thirteenth embodiment shown is that, in this embodiment, the number of the third well layers 321c is five, the number of the fourth well layers 321d is two, and the number of the fifth well layers 321e is also two.

[0202] Please refer to Fig. 27 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the sixteenth embodiment of the present invention. Fig.23 The difference of the thirteenth embodiment shown is that the number of the third well layers 321c is four, the number of the fourth well layers 321d is two, and the number of the fifth well layers 321e is three. Based on the above, as long as the number of the third well layers 321c is the largest, the embodiment of the present invention does not limit the number of the third well layers 321c, the number of the fourth well layers 321d, and the number of the fifth well layers 321e.

[0203] Please refer to Fig.28 , which is a schematic diagram of the bandgap structure of the light-emitting stack of the seventeenth embodiment of the present invention. Fig.23 The difference of the thirteenth embodiment shown is that the number of the second well layers 321 b is two, and the number of the third well layers 321 c is three.

[0204] Further, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) and the well layer 321 third closest to the N-type semiconductor layer 30 (first side 32a) are both second well layers 321b, and the well layer 321 second closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a. In other words, the first well layer 321a is located between two layers of the second well layer 321b.

[0205] Please refer to Fig.29, Fig.29 The photoelectric conversion efficiency of the light emitting diodes of different embodiments of the present invention is shown in FIG. 1 . It should be noted that the light emitting diodes M of these embodiments are operated at 25° C. and the current density is 120 mA / mm 2 The photoelectric conversion efficiency is measured under the condition of 60mA current driving 26×30mil 2 chip to measure the photoelectric conversion efficiency (WPE).

[0206] like Fig.29 As shown, at an operating current density of 120 mA / mm 2 In the embodiment of the present invention, the photoelectric conversion efficiency of the plurality of light emitting diodes M (including the light emitting stack 32 of the third embodiment, the sixth embodiment, the seventh embodiment, the ninth embodiment and the twelfth embodiment) is greater than 0.45. In a preferred embodiment (including the light emitting stack 32 of the twelfth embodiment), the photoelectric conversion efficiency of the light emitting diode M can even be greater than 0.59.

[0207] However, it is worth mentioning that the light emitting diode M provided by the embodiment of the present invention has an operating current density of 120 mA / mm 2 Under the above conditions, the photoelectric conversion efficiency is greater than 0.45. Therefore, the light emitting diode provided by the embodiment of the present invention can not only generate a light beam with a wide-band blue light spectrum, but also has a better photoelectric conversion efficiency.

[0208] In summary, one of the beneficial effects of the present invention is that in the epitaxial light-emitting structure 3 of the light-emitting diode M provided in the embodiment of the present invention, the spectrum of the epitaxial light-emitting structure 3 can have a larger half-width or multiple peaks through the technical means of "multiple well layers 321 are at least divided into a first well layer 321a and a second well layer 321b". In this way, the spectrum of the white light generated by the light-emitting diode module Z1 is a full spectrum or a healthy spectrum that meets the requirements, so as to be suitable for different lighting environments.

[0209] Furthermore, by adjusting the indium concentration in each well layer 321 of the epitaxial light-emitting structure 3 of the light-emitting diode M, a light beam with a wide-band blue light spectrum can be generated. Accordingly, the light-emitting diode Z13 of the embodiment of the present invention can not only generate light that meets the requirements of the natural light spectrum, but also meet the requirements of a variety of healthy spectra, and has a wide range of applications.

[0210] The contents disclosed above are only preferred feasible embodiments of the present invention, and are not intended to limit the protection scope of the claims of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention description and drawings are included in the protection scope of the claims of the present invention.

Claims

1. A light emitting diode, characterized in that: The light emitting diode has a multiple quantum well structure to generate a light beam with a wide-band blue light spectrum, and the light beam includes a first sub-beam with a first wavelength, a second sub-beam with a second wavelength, and a third sub-beam with a third wavelength, wherein the difference between the first wavelength and the second wavelength is between 1nm and 50nm, the difference between the first wavelength and the third wavelength is between 20nm and 70nm, the difference between the second wavelength and the third wavelength is between 10nm and 30nm, and the light beam emitted by the light emitting diode is at an operating current density of 120mA / mm 2 The WPE is greater than 0.

45.

2. The light emitting diode according to claim 1, characterized in that: The half-width of the waveform of the wide-band blue light spectrum is greater than 20 nm.

3. The light emitting diode according to claim 1, characterized in that: The multi-quantum well structure includes a first well layer for generating the first sub-beam and a second well layer for generating the second sub-beam, and the first well layer is adjacent to the second well layer.

4. The light emitting diode according to claim 3, characterized in that: The multi-quantum well structure further includes a third well layer for generating the third sub-beam. The third well layer is adjacent to the second well layer and is not adjacent to the first well layer.

5. The light emitting diode according to claim 1, characterized in that: The multiple quantum well structure includes a first well layer for generating the first sub-beam, a second well layer for generating the second sub-beam, and at least one barrier layer, wherein the first well layer and the second well layer are separated from each other by the at least one barrier layer.

6. The light emitting diode according to claim 5, characterized in that: The multi-quantum well structure further includes a third well layer for generating the third sub-beam, and the third well layer is adjacent to the second well layer, and the second well layer and the third well layer are separated from each other by at least one barrier layer.

7. A light emitting diode, characterized in that: The light emitting diode comprises: A P-type semiconductor layer; an N-type semiconductor layer; a first well layer for emitting light of a first wavelength, wherein the light of the first wavelength is the light of the longest wavelength emitted by the light emitting diode; and a second well layer for emitting light of a second wavelength; a third well layer for emitting light of a third wavelength; wherein at least one other well layer is provided between the first well layer and the P-type semiconductor layer, and the at least one other well layer emits light having a shorter wavelength than the first well layer, wherein the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength are mixed to form a light beam, the half-maximum width of the spectrum waveform of the light beam is greater than 20 nm, and the light beam emitted by the light emitting diode is at an operating current density of 120 mA / mm 2 The WPE is greater than 0.

45.

8. The light emitting diode according to claim 7, characterized in that: The difference between the second wavelength and the first wavelength is between 1 nm and 50 nm, the difference between the first wavelength and the third wavelength is between 20 nm and 70 nm, and the difference between the second wavelength and the third wavelength is between 10 nm and 30 nm.

9. The light emitting diode according to claim 7, characterized in that: The light of the first wavelength, the light of the second wavelength, and the light of the third wavelength are mixed to form a light beam, and the half-maximum width of the spectrum waveform of the light beam is greater than 20 nm.

10. A light emitting diode, characterized in that: The light emitting diode comprises: at least one first well layer, the first well layer having a first indium concentration; at least one second well layer, the second well layer having a second indium concentration; and at least one third well layer, the third well layer having a third indium concentration; The difference between the first indium concentration and the second indium concentration is at least 0.5%, the difference between the second indium concentration and the third indium concentration is at least 0.5%, and the light beam emitted by the light emitting diode is at an operating current density of 120 mA / mm 2 The WPE is greater than 0.

45.

11. The light emitting diode according to claim 10, characterized in that: The first well layer is adjacent to the second well layer, and the third well layer is adjacent to the second well layer and is not adjacent to the first well layer.

12. The light emitting diode according to claim 10, characterized in that: The first well layer and the second well layer are separated from each other, and the third well layer and the second well layer are divided from each other.

13. The light emitting diode according to claim 10, characterized in that: The light emitting diode further comprises at least one barrier layer, the material of the first well layer comprises indium gallium nitride, and the general formula of indium gallium nitride is InxGa (1-x) N, wherein x is between 0.12 and 0.2, and the material of the barrier layer includes gallium nitride.

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