JPH10190053A - Luminous device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contain red system luminous wavelength components having little changes in a color tone or a brightness for temperature changes by a method wherein a specific luminous element and a specific fluorescent substance are selected. SOLUTION: A main peak of luminous spectrum from a luminous element 102 is within 365nm-530nm. Further, a fluorescent substance is at least a type selected from aMgO.bLi2 O.Sb2 O3 :cMn, dMgO.eTiO2 :fMn,gMgO.hMgF2 .GeO2 : iMn,jCaO. kM1O.TiO2 :1Pr, mM22 O3 .(P1-n Vn )2 O5 :oEu2 O3 , M32 O2 S:pEu, M42 O:qEu (wherein a-q are composition ratios, and M1 is at least a type selected from Zn, Mg, Sr and Ba, and M2 is at least a type selected from La, Y, Sc, Lu and Gd, and M3 is at least a type selected from La, Y, Ga, Sc and Lu, and M4 is at least a type selected from La, Y and Ga).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an LED display,
The present invention relates to a light emitting device capable of emitting red light used for a backlight light source, a traffic light, an optical sensor, an optical printer head, an illuminated switch, various indicators, and the like. In particular, the present invention relates to a light-emitting device capable of emitting light with high luminance and high efficiency irrespective of a use environment and having little change in color tone or change in luminance with respect to temperature change, and a display device using the same.

[0002]

2. Description of the Related Art Light emitting diodes (hereinafter also referred to as LEDs)
And a laser diode (hereinafter also referred to as an LD) are small, efficient, and emit bright colors. In addition, since it is a semiconductor element, there is no fear of breaking the ball. Vibration and ON / OFF
It has the feature of being resistant to repeated lighting. Therefore, it is used as various indicators and various light sources. Recently, RGB has been used as a light emitting diode with ultra-high brightness and high efficiency.
Light emitting diodes such as (red, green, blue) have been developed respectively. Along with this, LED displays using the three primary colors of RGB are rapidly developing, taking advantage of features such as power saving, long life and light weight.

A light emitting diode can emit various emission wavelengths from ultraviolet to infrared depending on the semiconductor material of the light emitting layer used, forming conditions, and the like. Also,
It has an excellent monochromatic peak wavelength.

[0004] However, at present, only nitride-based compounds have been put into practical use as light-emitting elements capable of emitting relatively short wavelengths of blue or green light of visible light with high luminance.
In addition, a light-emitting element using a nitride-based compound semiconductor can emit light of various emission wavelengths with high luminance, but at present, a light-emitting element capable of emitting light with high efficiency in the long wavelength side of the visible region is formed. It is difficult.

On the other hand, light emitting diodes capable of emitting red light with high luminance include GaAlAs, GaAsP, and AlG.
Those having a light emitting layer such as aInP are used. Therefore, it is impossible to emit RGB (red, green, blue) light with high luminance using the same semiconductor. For blue and green, substantially the same semiconductor material can be used, but for red, a semiconductor material different from blue and green is used. Different semiconductor materials have different driving voltages and the like. Therefore, it is necessary to secure power supplies individually, and the circuit configuration becomes complicated. In addition, the rate of change of color tone and luminance with respect to temperature change is greatly different due to different semiconductor materials. FIG. 9 shows a specific example in which the characteristics of another light-emitting element (C is red) greatly differ from the luminance of a light-emitting element (A is blue and B is green) using a nitride-based compound semiconductor.

In the case where the RGB light emitting diodes emit light to display a mixed color, if the characteristics of the color tone and the luminance are largely different due to a temperature change or the like, the color balance is lost.
In particular, the human eye is sensitive to white and can discriminate even a small color shift. Therefore, when white light is emitted by using mixed color light of a light emitting element made of a semiconductor material having different RGB, white balance due to temperature change becomes a particularly serious problem. Such a change in color tone or change in luminance becomes a major problem in a display, an optical sensor, an optical printer, or the like.

Further, since a light emitting diode has an excellent monochromatic peak wavelength, in order to make it a white light emitting light source, it is necessary to arrange LED chips capable of emitting light of RGB or the like in close proximity to each other to emit light and diffuse color mixture. There is.
Such a light emitting diode is effective as a light emitting device that freely emits various colors. However, even when only a color such as white or pink is emitted, a blue-green or yellow light emitting diode or a red light , And green and blue light emitting diodes must be used. LED chips are semiconductors, and there is still considerable variation in color tone and brightness.

Further, as described above, it is necessary to adjust a current or the like for each semiconductor to emit a desired light such as a white light. In the case of a light-emitting element using a different semiconductor material, differences in individual temperature characteristics and changes over time are greatly different, and the color tone and the like may be variously changed. Even if white light or the like is set at the start of use, color shift or uneven brightness may occur due to heat generation of the light emitting diode itself. Furthermore, if the light emitted from the LED chips is not uniformly mixed, color unevenness may occur.

The present applicant has previously disclosed a light emitting diode in which the color of light emitted from an LED chip has been converted by using a fluorescent substance as disclosed in Japanese Patent Laid-Open Publication No.
The light emitting diodes described in JP 152609, JP-A-7-99345, and the like have been developed. With these light-emitting diodes, other light-emitting colors can be efficiently emitted using an LED chip that emits blue light.

Specifically, an LED chip having a large energy band gap of the light emitting layer is disposed on a cup provided at the tip of a lead frame. LED chip,
Each is electrically connected to a metal stem or a metal post provided with an LED chip. Further, a fluorescent substance that absorbs light from the LED chip and converts the wavelength is contained in a resin mold member that covers the LED chip. Thus, a light emitting diode capable of absorbing blue light from the LED chip and emitting another color with high luminance can be obtained.

As the fluorescent substance excited by the emission wavelength of the light emitting element, there are various fluorescent dyes, fluorescent pigments, and various organic and inorganic compounds. In addition, fluorescent materials include those having a long persistence and those having substantially no afterglow.
Further, there is a type that converts the emission wavelength from a light emitting element from a short wavelength to a long wavelength, or that converts the emission wavelength from a long wavelength to a short wavelength.

[0012]

However, when converting from a long wavelength to a short wavelength, the conversion efficiency is extremely poor and not suitable for practical use. Further, since the multi-stage excitation is required, the light emission amount does not increase linearly with respect to the excitation wavelength amount. In addition, the fluorescent substance disposed in the vicinity of the light emitting element is exposed to a light beam having a strong irradiation intensity that is about 30 to 40 times that of sunlight. In particular, when the LED chip, which is a light emitting element, uses a semiconductor having a high energy band gap to improve the conversion efficiency of the fluorescent substance or reduce the amount of the fluorescent substance used, the light emitted from the LED chip is in the visible light range. But the light energy is inevitably higher. Light energy is extremely high in the ultraviolet region. In this case, if the luminous intensity is further increased and used for a long period of time, the fluorescent substance itself may be easily deteriorated. When the fluorescent substance is deteriorated, the color tone may be deviated, or the efficiency of external extraction of light may decrease.

[0013] Similarly, the fluorescent substance provided in the vicinity of the light emitting element is also exposed to a high temperature such as a temperature rise of the light emitting element or heating from an external environment. When using as a light emitting diode,
In general, although covered with a resin mold, it is not possible to completely prevent entry of moisture from the external environment.
Further, it is not possible to completely remove the moisture attached during the production. Depending on the fluorescent substance, such moisture may accelerate the deterioration of the fluorescent substance by high-energy light or heat from the light emitting element. In addition, ionic organic dyes cause electrophoresis by a DC electric field near the chip,
The color may change.

Further, ions generated by the decomposition of the fluorescent substance contaminate the light emitting element, or a cup reflecting the wavelength from the light emitting element, a conductive wire for electrically connecting the light emitting element, and the like are deteriorated, and the extraction efficiency is reduced. It may decrease.

Therefore, the present invention solves the above problems,
It is an object of the present invention to provide a light-emitting device including a red-based light-emitting wavelength component in which a change in color tone or luminance is small with a change in temperature.
It is another object of the present invention to provide a light emitting device including a red light emitting wavelength component with extremely low light emission rate and extremely little color shift even under a higher luminance and longer use environment. In particular, it is an object of the present invention to provide a light emitting device capable of emitting a red light emission wavelength component having various characteristics and a nitride compound semiconductor capable of emitting another color different from the red light.

[0016]

The present invention has at least the following features.
A light-emitting element in which the optical layer is a gallium nitride-based compound semiconductor;
Absorbs at least part of the emission wavelength emitted by the light emitting element
And a fluorescent substance that emits light after wavelength conversion.
is there. In particular, the emission spectrum from the light emitting element has a main peak
Within 365 nm to 530 nm as well as fluorescence
The substance is aMgO · bLi_TwoO ・ Sb_TwoO_Three: CMn, dM
gO ・ eTiO_Two: FMn, gMgO.hMgF_Two・ Ge
O_Two: IMn, jCaO · kM1O · TiO_Two: LPr,
mM2_TwoO _Three・ (P_1-nV_n)_TwoO_Five: OEu_TwoO_ThreeSelected from
Is at least one kind.

However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.00
1 ≦ c ≦ 0.05, 1 ≦ d ≦ 3, 1 ≦ e ≦ 2, 0.00
1 ≦ f ≦ 0.05, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05. M1 is Zn, Mg, Sr,
At least one selected from Ba. j + k + 1 = 1,
0 <k ≦ 0.4, 0.00001 ≦ l ≦ 0.2. M2 is at least one selected from La, Y, Sc, Lu, and Gd. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.001 ≦
o ≦ 0.5.

According to a second aspect of the present invention, in the light emitting device, the light emitting layer is at least a nitride compound semiconductor and emits visible light, and the light emitting element is excited by the visible light emitting wavelength of the light emitting element and is longer than the light emitting wavelength. A fluorescent substance that emits fluorescence of a wavelength. In particular, a non-doped InαAlβGa _1- α ₋ having a double hetero structure is provided between the n-type nitride-based compound semiconductor layer and the p-type nitride-based compound semiconductor layer.
It has an active layer of βN layer, the α value of the InαAlβGa ₁ -α _- βN layer is 0 or more, the β value is 0 or more, the α + β value is less than 1,
The thickness of the nαAlβGa ₁ -α _- βN layer is less than 100 Å, and the composition formula of the phosphor is aMgO
BLi ₂ O Sb ₂ O ₃ : cMn, dMgO eTi
_{O 2: fMn, gMgO · hMgF} 2 · GeO 2: iMn
At least one selected from the group consisting of:

However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.00
1 ≦ c ≦ 0.05, 1 ≦ d ≦ 3, 1 ≦ e ≦ 2, 0.00
1 ≦ f ≦ 0.05, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05.

According to a third aspect of the present invention, in the light emitting device, the light emitting layer is at least a nitride compound semiconductor and emits visible light, and the light emitting element is excited by the visible light emitting wavelength of the light emitting element and is longer than the light emitting wavelength. A fluorescent substance that emits fluorescence of a wavelength. In particular, the light emitting element has a double hetero structure between the n-type nitride-based compound semiconductor layer and the p-type nitride-based compound semiconductor layer, and has a p-type impurity containing InαAlβGa _1−.
It has an active layer of α _- βN layer, and has an InαAlβGa _1- α _- βN
Α value of the layer is 0 or more, β value is 0 or more, α + β value is less than 1,
The thickness of the InαAlβGa ₁ -α _- βN layer is 100 Å or more, and the composition formula of the fluorescent substance is aMg.
_{O · bLi 2 O · Sb 2} O 3: cMn, dMgO · eTi
_{O 2: fMn, gMgO · hMgF} 2 · GeO 2: iMn
At least one selected from the group consisting of:

However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.00
1 ≦ c ≦ 0.05, 1 ≦ d ≦ 3, 1 ≦ e ≦ 2, 0.00
1 ≦ f ≦ 0.05, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05.

According to a fourth aspect of the present invention, there is provided a light emitting device, wherein the light emitting layer is at least a nitride-based compound semiconductor and emits ultraviolet light. And a fluorescent substance that emits fluorescent light. In particular, the light-emitting element has an active layer of an InαGa ₁ -αN layer having a double hetero structure and containing an n-type impurity between the n-type nitride-based compound semiconductor layer and the p-type nitride-based compound semiconductor layer, n-type impurity concentration of 5 × 10 ¹⁷ / cm ³
, The α value of the InαGa ₁ -αN layer is larger than 0 and 0.1
Hereinafter, the thickness of the InαGa ₁ -αN layer is 100 Å or more and 1000 Å or less, and the composition formula of the fluorescent substance is gMgO.hMgF ₂ .Ge.
O ₂ : iMn, jCaO · kM1O · TiO ₂ : lPr,
_{mM2 2 O 3 · (P 1} -n V n) 2 O 5: oEu 2 O 3, M3 2 O 2
It is at least one selected from S: pEu and M4 ₂ O: qEu.

However, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05. M1 is Zn, Mg, Sr,
At least one selected from Ba. j + k + 1 = 1,
0 <k ≦ 0.4, 0.00001 ≦ l ≦ 0.2. M2 is at least one selected from La, Y, Sc, Lu, and Gd. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.001 ≦
o ≦ 0.5. M3 is at least one selected from La, Y, Ga, Sc, and Lu. 0.0005 ≦ p ≦ 0.1.
M4 is at least one selected from La, Y, and Ga.
0.0005 ≦ q ≦ 0.1.

According to a fifth aspect of the present invention, in the light emitting device, the light emitting layer is at least a nitride-based compound semiconductor and emits ultraviolet light, and a light emitting element excited by the ultraviolet light emitting wavelength of the light emitting element has a longer wavelength than the light emitting wavelength. And a fluorescent substance that emits fluorescent light. In particular, the light-emitting element has an active layer of an InδGa _1- δN layer having a double hetero structure and containing an n-type impurity, between the n-type nitride-based compound semiconductor layer and the p-type nitride-based compound semiconductor layer, The impurity concentration is 5 × 10 ¹⁷ / cm ³ or more, the δ value of the InδGa _1- δN layer is more than 0 and 0.1 or less, the thickness of the InδGa _1- δN layer is 100 Å or more, and the composition formula of the fluorescent substance Is gMgOh
MgF ₂ · GeO ₂ : iMn, jCaO · kM1O · Ti
O ₂ : lPr, mM _{2 2} O ₃ · (P ₁ -nV _n ) ₂ O ₅ : oEu ₂
It is at least one selected from O ₃ , M3 ₂ O ₂ S: pEu, and M4 ₂ O: qEu.

However, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05. M1 is Zn, Mg, Sr,
At least one selected from Ba. j + k + 1 = 1,
0 <k ≦ 0.4, 0.00001 ≦ l ≦ 0.2. M2 is at least one selected from La, Y, Sc, Lu, and Gd. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.001 ≦
o ≦ 0.5. M3 is at least one selected from La, Y, Ga, Sc, and Lu. 0.0005 ≦ p ≦ 0.1.
M4 is at least one selected from La, Y, and Ga.
0.0005 ≦ q ≦ 0.1.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of various experiments, the present inventors have found that a light-emitting device that converts a light-emitting wavelength from a light-emitting element that emits light with a relatively high light energy by a fluorescent substance has a specific light-emitting element. Further, the present invention has been found that by selecting a specific fluorescent substance, it is possible to prevent a decrease in light efficiency and color shift during high-intensity and long-time use and to emit light with high luminance.

In particular, the nitride compound semiconductor used in the light emitting device of the present invention can efficiently emit light from ultraviolet to blue and green (the main peak of the emission wavelength is from 365 nm to 530 nm). However, when viewed from a fluorescent substance, the excitation wavelength range of the excitation light source is extremely narrow as described above, and has a peak. Therefore, in order to improve the luminous intensity and the luminous efficiency of the light emitting device, a combination with the selected specific light emitting element and specific fluorescent material is required.

That is, the fluorescent substance used in the light emitting device includes: Excellent light fastness is required. In particular, a fluorescent substance provided in contact with or in close proximity to a light-emitting element because it is strongly radiated from a minute region such as a light-emitting element can sufficiently withstand a strong irradiation intensity of about 30 to 40 times that of sunlight. There is a need. When the light emitting element emits light in the ultraviolet region, durability against ultraviolet rays is also required.

2. To be efficiently excited with respect to the emission wavelength from the nitride-based compound semiconductor in order to improve the emission light efficiency.

3. Be able to emit light efficiently by excitation.

4. When it is arranged near a light emitting element, it has good temperature characteristics.

5. 5. Have weather resistance according to the usage environment of the light emitting diode. Do not damage the light emitting elements.

[7] It is required that the color tone has a characteristic that it can be continuously changed by a composition ratio or a mixture ratio of a plurality of fluorescent substances.

According to the present invention, assuming that these conditions are satisfied, a nitride compound semiconductor device having a high energy band gap in a light emitting layer as a light emitting device, aMgO.bLi ₂ O.Sb ₂ O ₃ : cMn as a fluorescent material, dMgO
· ETiO ₂ : fMn, gMgO · hMgF ₂ · Ge
O ₂ : iMn, jCaO · kM1O · TiO ₂ : lPr,
_{mM2 2 O 3 · (P 1} -n V n) 2 O 5: oEu 2 O 3, M3 2 O 2
At least one selected from S: pEu and M4 ₂ O: qEu is used. As a result, even when the high-energy light emitted from the light-emitting element is irradiated with high luminance for a long time in the vicinity of a long time, a long-wavelength component that is a red-based light-emitting wavelength component in which the color shift of the emission color and the decrease in emission luminance are extremely small. Can be obtained as a light emitting device having high luminance.

FIG. 2 shows a chip type LED as an example of a specific light emitting device. Chip type LED housing 2
LED chip 2 using gallium nitride based semiconductor in 04
02 is fixed by die bonding using an epoxy resin or the like. A gold wire as the conductive wire 203 is electrically connected to each electrode of the LED chip 202 and each electrode 205 provided on the housing. 5MgO.3Li ₂ O
・ Mg ₅ Li ₆ Sb ₂ O ₁₃ : Mn mixed and dispersed in epoxy resin as Sb ₂ O ₅ is uniformly filled and cured as a mold member 201 for protecting LED chips, conductive wires and the like from external stress and the like. Let it form. By supplying power to such a light emitting diode, an LED
The chip 202 is caused to emit light. The light emitting device can emit light emitted from a fluorescent substance excited by light emitted from the LED chip 202 or mixed light of light emitted from the fluorescent substance and light emitted from the LED chip 202. Hereinafter, the constituent members of the present invention will be described in detail.

(Fluorescent substance) The fluorescent substance used in the present invention
The light-emitting element is excited by the emission wavelength of the light-emitting element
A fluorescent substance that emits light at a wavelength longer than the excitation wavelength
U. Specific fluorescent substances include aMgO.bLi_TwoO
・ Sb_TwoO_Three: CMn, dMgO.eTiO_Two: FMn,
gMgO ・ hMgF_Two・ GeO_Two: IMn, jCaO · k
M1O ・ TiO _Two: LPr, mM2_TwoO_Three・ (P_1-nV_n)_Two
O_Five: OEu_TwoO_Three, M3_TwoO_TwoS: pEu, M4_TwoO: qE
at least one selected from u.

(However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.0
01 ≦ c ≦ 0.05, 1 ≦ d ≦ 3, 1 ≦ e ≦ 2, 0.0
01 ≦ f ≦ 0.05, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦
1, 0.003 ≦ i ≦ 0.05. M1 is Zn, Mg, S
at least one selected from r and Ba. j + k + 1 =
1, 0 <k ≦ 0.4, 0.00001 ≦ l ≦ 0.2. M
2 is at least one selected from La, Y, Sc, Lu, and Gd. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.00
1 ≦ o ≦ 0.5. M3 is at least one selected from La, Y, Ga, Sc, and Lu. 0.0005 ≦ p ≦ 0.
One. M4 is at least one selected from La, Y, and Ga
seed. 0.0005 ≦ q ≦ 0.1. In order to emit only visible light from the fluorescent substance to the outside, the excitation wavelength emitted from the nitride-based compound semiconductor to excite the fluorescent substance is set in the ultraviolet range. Alternatively, substantially all of the excitation wavelength emitted by the light emitting element is converted by the fluorescent substance. Moreover,
The light emitted from the light emitting element and not converted by the fluorescent substance is absorbed by a pigment or the like, so that only visible light from the fluorescent substance can be emitted to the outside.

On the other hand, when both the visible light emission wavelength emitted from the light emitting element and the fluorescence from the fluorescent substance are emitted to the outside,
It is necessary that the visible light emission wavelength from the light emitting element and the fluorescence from the fluorescent substance pass through the mold member or the like outside the light emitting device. Therefore, a light-emitting device in which a light-emitting element is confined in a layer of a fluorescent substance in which a fluorescent substance is formed by a sputtering method or the like and one or two or more openings through which light from the light-emitting element is transmitted in the fluorescent substance layer may be provided. . Further, the fluorescent material layer is formed thin enough to transmit light from the light emitting element. Similarly, a fluorescent substance powder may be contained in a resin or glass so as to be thin enough to transmit light from the light emitting element. By variously adjusting the ratio of the fluorescent substance to the resin, the application and the filling amount, and selecting the emission wavelength of the light emitting element, any color tone including a red emission wavelength can be provided.

The distribution of the content of the fluorescent substance may affect the color mixing property and the durability in some cases. That is, when the distribution concentration of the fluorescent substance is high from the surface of the coating portion or the mold member containing the fluorescent substance toward the light emitting element, the fluorescent substance is less susceptible to external force and moisture from the external environment, and the external force and moisture It is easy to suppress the deterioration due to. On the other hand, when the content distribution of the fluorescent substance is increased from the light emitting element toward the mold member surface side, the distribution concentration is easily affected by moisture and the like from the external environment, but the influence of heat generation and irradiation intensity from the light emitting element is reduced. be able to. Such a distribution of the fluorescent substance can be variously formed by adjusting the member containing the fluorescent substance, the forming temperature, the viscosity, the shape, the particle size, the particle size distribution, and the like of the fluorescent substance. Therefore, the distribution concentration of the fluorescent substance can be variously selected depending on the use conditions and the like. For the purpose of suppressing and controlling such distribution with good dispersibility, it is preferable that the average particle size of the fluorescent substance is 0.2 μm to 0.7 μm. Further, the particle size distribution is preferably 0.2 <log sigma <0.45.

The fluorescent substance of the present invention is particularly arranged in contact with or in close proximity to the light emitting element and has an irradiance (Ee) = 3.
It can be a light emitting device having sufficient light resistance in high efficiency W · cm ^-2 or more 10 W · cm ^-2 or less.

(AMgO.bLi ₂ O.Sb ₂ O ₃ : cMn
Fluorescence Generation of _{substance) aMgO · bLi 2 O · Sb} 2 O 3:
Examples of the method for producing the cMn fluorescent substance include MgCO ₃ , L
i ₂ CO ₃ , Sb ₂ O ₃ , and MnCO ₃ are used as raw materials at a molar ratio of 5: 3: 1: 0.001 to 0.05, respectively. The respective oxides are sufficiently mixed using a ball mill or the like and packed in an alumina crucible or the like. Crucible from 1250 to 1
It was fired in air at 400 ° C. for about 2 hours, and further fired in an oxygen atmosphere at 560 ° C. for 10 hours or more to obtain a fired product. Washed calcined product is ball in methanol, separated, dried, Mg ₅ used in the present invention through the last sieve
A Li ₆ Sb ₂ O ₁₃ : Mn phosphor can be formed. In particular, in order to emit light with high luminance, 2 ≦ a ≦ 6,
It is preferable that 2 ≦ b ≦ 4 and 0.001 ≦ c ≦ 0.05. This fluorescent substance is easily excited by visible light on the short wavelength side which is the emission wavelength from the light emitting element of the present invention.

(Method for producing dMgO.eTiO ₂ : fMn fluorescent substance) As an example of the method for producing the dMgO.eTiO ₂ : fMn fluorescent substance, MgCO ₃ , TiO ₂ , and MnCO ₃ are used as raw materials at 2: 1: 0.001 respectively. Used in a molar ratio of ０．０５0.05. The respective oxides are sufficiently mixed using a ball mill or the like and packed in an alumina crucible or the like. 1 crucible
It is fired in air at a temperature of 250 to 1400 ° C. for about 2 hours, and further fired in an oxygen atmosphere at 560 ° C. for 10 hours or more to obtain a fired product. The calcined product can be ball-milled in methanol, washed, separated, dried, and finally passed through a sieve to form the Mg ₂ TiO ₄ : Mn phosphor used in the present invention. In particular, in order to emit light with high luminance, 1 ≦ d ≦
It is preferred that 3, 1 ≦ e ≦ 2 and 0.001 ≦ f ≦ 0.05. This fluorescent substance is also easily excited by visible light on the short wavelength side which is the emission wavelength from the light emitting element of the present invention.

[0043] _{(gMgO · hMgF 2 · GeO 2} : iMn
Method for producing fluorescent substance) gMgO.hMgF ₂ .GeO ₂ : i
Examples of the method of producing the Mn fluorescent material include MgCO ₃ , Ge
Using O ₂ and MnCO ₃ as raw materials, respectively, 3.5: 0.5:
1: Used in a molar ratio of 0.001 to 0.05. The respective oxides are sufficiently mixed using a ball mill or the like and packed in an alumina crucible or the like. The crucible is fired in the air at a temperature of 1100 to 1250 ° C., and further fired in an oxygen atmosphere at 560 ° C. for 10 hours or more to obtain a fired product. Washed calcined product is ball in water, separation, drying, finally used in the present invention through a sieve to 3.5MgO · 0.5MgF ₂ · Ge
O ₂ : Mn phosphor can be formed. The peak wavelength of this fluorescent substance is 658 nm. In particular, in order to emit light with high luminance, 2.5 ≦ g ≦ 4.0 and 0 ≦ h
It is preferable that ≦ 1, 0.003 ≦ i ≦ 0.05. This fluorescent substance is easily excited in the visible light and ultraviolet regions on the short wavelength side from the light emitting device of the present invention.

(JCaO · kM1O · TiO ₂ : lPr
Method for producing fluorescent substance) jCaO · kM1O · TiO ₂ : l
As a method for producing the Pr fluorescent substance, CaCO ₃ , TiO ₂ ,
Pr ₆ O ₁₁ and H ₃ BO ₃ are mixed in a ball mill and fired at 1200 to 1400 ° C. for about 2 hours in the air. The calcined product may be pulverized, washed, separated and dried, and finally passed through a sieve to form the CaTiO ₃ : Pr phosphor used in the present invention. The peak wavelength of this fluorescent substance is 614 nm. M1 is at least one selected from Zn, Mg, Sr, and Ba, and any element can emit light in the same manner. In order to emit light with high brightness,
j + k + 1 = 1, 0 <k ≦ 0.4, 0.00001 ≦ l
The range of ≦ 0.2 is preferred. This fluorescent substance emits light by being suitably excited in the ultraviolet region from the light emitting device of the present invention.

(MM ₂ O _3. (P ₁ -nV _n ) ₂ O ₅ : oEu
Method for producing ₂ O ₃ fluorescent substance) mM _{2 2} O ₃ · (P _1-n V _n )
_{As a} method for producing ₂ O ₅ : oEu ₂ O ₃ fluorescent substance, Y ₂ O ₃ ,
Eu ₂ O ₃ , (NH ₄ ) ₂ HPO ₄ , and V ₂ O ₅ were mixed in a ball mill and packed in an alumina crucible.
Bake in air for about an hour. The calcined product is ball-milled in water, pulverized, washed, separated and dried, and finally passed through a sieve to form the Y (PV) O ₄ : Eu phosphor used in the present invention. The peak wavelength of this fluorescent substance is 62
0 nm. M2 is Y, La, Sc, Lu, G
At least one element selected from d, and any element can emit light similarly. Further, in order to emit light with high luminance, 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.0
The range of 01 ≦ o ≦ 0.5 is preferable. This fluorescent substance emits light by being suitably excited in the ultraviolet region from the light emitting device of the present invention.

(Method for producing M3 ₂ O ₂ S: pEu fluorescent substance)
An example of a method for producing the M3 ₂ O ₂ S: pEu fluorescent substance is Y ₂
O ₃ and Eu ₂ O ₃ are dissolved in hydrochloric acid and coprecipitated as nitrates. At this time, the amount of Eu ₂ O ₃ is preferably 0.1 to 20 mol%. The precipitate is calcined at 800 to 1000 ° C. in air to form an oxide. The obtained oxide is mixed with sulfur, sodium carbonate and flux, and placed in an alumina crucible.
It is fired at a temperature of 0 ° C. to 1200 ° C. for 2 to 3 hours to obtain a fired product. The fired product can be pulverized, washed, separated and dried, and finally passed through a sieve to form the Y ₂ O ₂ S: Eu phosphor used in the present invention. The peak wavelength of this fluorescent substance is 627 nm. M3 is Y, La, G
It is at least one selected from a, Sc, and Lu, and any element can emit light in the same manner. Further, in order to emit light with high luminance, the range of 0.0005 ≦ p ≦ 0.1 is preferable. This fluorescent substance emits light by being suitably excited in the ultraviolet region from the light emitting device of the present invention.

(Method for producing M4 ₂ O: qEu fluorescent substance) M
As an example of the method of producing the 4 ₂ O: qEu fluorescent substance, boron is added as a flux to Y ₂ O ₃ and Eu ₂ O ₃ and dry-mixed for 3 hours. The mixed raw material is fired in air at 1200 ° C. to 1600 ° C. for about 6 hours to obtain a fired product. The baked product is dispersed by milling in a wet system, and the Y ₂ O ₃ : Eu phosphor used in the present invention can be formed through washing, dispersion, drying, and dry sieving. The peak wavelength of this fluorescent substance is 611 nm. M4 is at least one selected from Y, La, and Ga, and any element can emit light in the same manner. Further, in order to emit light with high luminance, the range of 0.0005 ≦ q ≦ 0.1 is preferable. This fluorescent substance emits light by being suitably excited in the ultraviolet region from the light emitting device of the present invention.

(Other Fluorescent Substances Used with the Fluorescent Substance of the Present Invention) The fluorescent substances used in the present invention include those capable of efficiently emitting light by ultraviolet rays and those capable of emitting light efficiently on the long wavelength side of visible light. Therefore, it can be used as a light-emitting device using a nitride-based compound semiconductor capable of emitting a red light-emitting component when excited by an excitation wavelength from a light-emitting element. In addition to the fluorescent substance of the present invention, it is also possible to add a fluorescent substance which has the same characteristics as the present invention, such as light resistance, and which can be excited by the emission wavelength from the light emitting element and emit light of another wavelength different from the present invention. By including a plurality of fluorescent substances, it is possible to increase the RGB wavelength components of light from the light emitting device and to emit various luminescent colors including a red luminescent wavelength.

In addition to the fluorescent substance of the present invention, a fluorescent substance capable of efficiently emitting visible light of a relatively short wavelength side includes an yttrium-aluminum-garnet-based fluorescent substance activated with cerium. The yttrium-aluminum-garnet-based fluorescent material activated with cerium emits yellow light by receiving blue light having a short wavelength of visible light while having the same light resistance as the fluorescent material used in the present invention. . A mixture of blue from the nitride-based compound semiconductor and yellow of the yttrium-aluminum-garnet-based fluorescent material activated with cerium enables light emission, high luminance and high color rendering white light emission. it can.

The yttrium-aluminum-garnet fluorescent material activated with cerium includes various replaceable materials. Specifically, (Re _1-x S
_{m X) 3 (Al 1-} yz In y Ga z) 5 O 12: Ce ( provided that 0
≦ x <1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, 0 ≦ y + z ≦ 1,
Re is at least one element selected from the group consisting of Y, Gd, and La. )).

(Re _1-x Sm _X ) ₃ (Al _1-yz In _y G
a _z ) ₅ O ₁₂ : Ce has a garnet structure and thus is resistant to heat, light and moisture, and can have an excitation spectrum peak near 450 nm. The emission peak is 530n.
A broad emission spectrum near m can be obtained. In addition, the emission wavelength shifts to a short wavelength by substituting a part of the Al in the composition with Ga, and the emission wavelength shifts to a long wavelength by substituting a part of the Y in the composition with Gd. By changing the composition in this way, the emission color can be adjusted to some extent continuously.

In addition, LE using nitride-based compound semiconductor
The light efficiency can be further improved by having a D chip and a fluorescent material containing a rare earth element samarium (Sm) in a yttrium aluminum garnet fluorescent material (YAG) activated with cerium.

Such fluorescent substances include Y, Gd, Ce,
An oxide or a compound which easily becomes an oxide at a high temperature is used as a raw material of Sm, La, Al and Ga, and these are sufficiently mixed in a stoichiometric ratio to obtain a raw material. Or Y, Gd,
A co-precipitated oxide obtained by calcining a solution obtained by dissolving a rare earth element of Ce, La, and Sm in an acid at a stoichiometric ratio with oxalic acid, and aluminum oxide and gallium oxide are mixed and mixed. Get the raw materials. An appropriate amount of a fluoride such as ammonium fluoride is mixed into the crucible as a flux, and the mixture is baked in air at a temperature range of 1350 to 1450 ° C for 2 to 5 hours to obtain a baked product. It can be obtained by ball milling, washing, separating, drying and finally passing through a sieve.

The yttrium / aluminum / garnet-based fluorescent material activated with cerium shifts the emission wavelength to the longer wavelength side by replacing yttrium with gadolinium, but the brightness decreases rapidly when the replacement amount is increased.
Therefore, by using the fluorescent substance of the present invention in addition to the yttrium-aluminum-garnet-based fluorescent substance activated with cerium, it is possible to obtain a white substance or the like containing a more reddish light-emitting component with high luminance. Similarly, by adjusting the mixing ratio of the fluorescent substance, it is possible to emit light of pink color or the like.

Also, the light emitted from the nitride-based compound semiconductor is
When the emission wavelength is in the ultraviolet range, the fluorescent substance of the present invention
Adds a fluorescent substance that can emit blue or green light in response to ultraviolet light
It is also possible to obtain an arbitrary luminescent color such as white. Fluorescent material
The desired color can be obtained by the mixing amount of
You. Specifically, Sr is used as a fluorescent substance capable of emitting blue light.
_TwoP_TwoO₇: Eu, Sr_Five(PO_Four)_ThreeCl: Eu, (SrC
aBa)_Three(PO_Four)₆Cl: Eu, BaMg_TwoAl
₁₆O₂₇: Eu, SrO ・ P_TwoO_Five・ B_TwoO_Five: Eu, (Ba
Ca)_Five(PO_Four)_ThreeCl: Eu and the like are preferred.
You. ZnSiO as a fluorescent substance capable of emitting green light_Four: M
n, Zn_TwoSiO_Four: Mn, LaPO_Four: Tb, SrAl_Two
O_Four: Eu and the like are preferable. Can emit white light
YVO as fluorescent substance_Four: Dy and the like are preferred.
You.

When a plurality of types of fluorescent materials are used, a plurality of fluorescent materials are contained in a light-transmitting inorganic member such as glass or a light-transmitting organic member such as a resin which is a coating part and / or a mold member. It may be formed by mixing,
It may be formed as a multilayer film for each fluorescent substance. Further, a fluorescent substance is applied to an inner wall and / or an outer wall of a transparent inorganic member, such as glass, together with a binder. After the coating, the fluorescent substance from which the binder has been removed by incineration of the binder may be irradiated with an excitation wavelength from the light emitting element to emit light.

As described above, by using another fluorescent substance, it is possible to arbitrarily change the color rendering of light emitted from the light emitting device. In addition, since light emission including RGB components is possible, it can be used as a backlight for a full-color display device or a full-color liquid crystal display device through a color filter.

(Light emitting elements 102, 202, 302, 80)
2) The light emitting element used in the present invention is aMgO.bL
_{i 2 O · Sb 2 O 3} : cMn, dMgO · eTiO 2: fM
_{n, gMgO · hMgF 2 · GeO} 2: iMn, jCaO
_{· KM1O · TiO 2: lPr,} mM2 2 O 3 · (P 1-n V
_n ) ₂ O ₅ : oEu ₂ O ₃ , M3 ₂ O ₂ S: pEu, M4 ₂ O:
A nitride-based compound semiconductor that can efficiently excite at least one kind of fluorescent substance selected from qEu is exemplified. The light-emitting element has a nitride-based compound semiconductor formed on a substrate by MOCVD, HVPE, or the like. As the nitride-based compound semiconductor, InαAlβGa ₁ -α _- βN (where 0 ≦ α, 0 ≦ β, α + β ≦ 1) is formed as a light emitting layer. Semiconductor structures include MIS junction, PI
Examples include a homostructure having an N junction or a PN junction, a heterostructure, or a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal thereof. Also, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed as a thin film in which a quantum effect occurs can be used.

[0059] In addition to the substrate to form a nitride compound semiconductor is sapphire C plane, sapphire having the principal R-plane, A plane, other, other insulating substrate such as spinel (MgA1 ₂ O ₄₎ , SiC (including 6H, 4H, 3C), S
Materials such as i, ZnO, GaAs, and GaN crystal can be used. In order to relatively easily form a nitride-based compound semiconductor having good crystallinity, it is preferable to use a sapphire substrate (C-plane), and to form a buffer layer to correct lattice mismatch with the sapphire substrate. desirable. The buffer layer can be formed of aluminum nitride, gallium nitride, or the like formed at a low temperature. Further, the buffer layer may be formed of two or more layers in order to influence the crystallinity of the nitride-based compound semiconductor formed thereon.

In this case, a low-temperature growth buffer layer can be formed on the sapphire substrate, and a second buffer layer can be formed thereon. The second buffer layer grown in contact with the low-temperature growth buffer layer is preferably made of an undoped nitride-based compound semiconductor, particularly preferably undoped GaN.
When undoped GaN is used, the crystallinity of a nitride-based compound semiconductor doped with an n-type impurity to be grown thereon can be further improved. It is desirable that the second buffer layer be grown to a thickness of 100 Å or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less.

In the case where the second buffer layer is not a clad layer but an underlayer for producing a GaN substrate,
Al _v Ga _1-v N (0 ≦
v ≦ 0.5). If the v value of the Al mixed crystal ratio exceeds 0.5, cracks tend to occur in the crystals themselves rather than crystal defects. for that reason,
The crystal growth itself tends to be difficult. The film thickness is 10
It is more preferable to adjust it to not more than μm. Further, the second buffer layer may be doped with n-type impurities such as Si and Ge.

As an example of a light emitting device having a pn junction using a nitride-based compound semiconductor, a first contact layer formed of n-type gallium nitride and a first contact layer formed of n-type aluminum gallium nitride on a buffer layer 1 cladding layer, indium nitride doped with p-type impurities such as Zn.
A structure in which an active layer formed of gallium, a second cladding layer formed of p-type aluminum-gallium nitride, and a second contact layer formed of p-type gallium nitride can be sequentially stacked.

The gallium nitride-based semiconductor exhibits n-type conductivity without being doped with impurities. When a desired n-type gallium nitride semiconductor is formed, for example, to improve luminous efficiency, Si, Ge, Se, Te, C
It is preferable to introduce such as appropriate. On the other hand, in the case of forming a P-type gallium nitride semiconductor, P-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since gallium nitride-based compound semiconductors are difficult to become p-type only by doping with a p-type dopant, it is preferable to make the g-type compound semiconductor p-type by introducing a p-type dopant and then annealing by heating in a furnace, low-speed electron beam irradiation, plasma irradiation, or the like. .

In particular, when light is emitted in the ultraviolet region from about 365 nm to 400 nm or less, a double hetero structure is formed between the n-type gallium nitride and the p-type gallium nitride so that the n-type impurity concentration is 5 × 10 ¹⁷ / g. Indium nitride less than cm ³
Gallium (InαGa ₁ -αN) having a thickness of 100
Angstroms or more and 1000 Angstroms or less,
When the value α of In is more than 0 and 0.1 or less, light can be emitted with high efficiency. The n-type impurity is Si,
At least one selected from S, Ge, and Se.
The thickness is preferably 100 Å or more and 1000 Å or less, more preferably 200 Å or less.
Angstrom or more, 800 angstrom or less,
Most preferably, it is not less than 250 angstroms and not more than 700 angstroms.

Similarly, a double heterostructure is formed between the n-type gallium nitride and the p-type gallium nitride to form an indium gallium nitride (InδGa ₁ -δN) having an n-type impurity concentration of 5 × 10 ¹⁷ / cm ³ or more. ), It is possible to emit light with high efficiency in the ultraviolet region from about 365 nm to 400 nm by setting the film thickness to 100 angstroms or more and the value of In more than 0 and 0.1 or less. Note that the n-type impurity is at least one selected from Si, S, Ge, and Se. The thickness is preferably 100 angstroms or more, more preferably 200 angstroms or more.

As a light emitting element having a high output in the ultraviolet region, G
Assuming aN, light emission of about 365 nm can be obtained. However, the output is very low and if Al is included, the output tends to further decrease. This is AlG
It is presumed to be due to the crystallinity of aN and InAlN. AlG
When the active layer is made of aN, InAlN, or the like, it is necessary to form a clad layer having a high Al mixed crystal ratio due to the band gap energy. Since a clad layer having a high Al mixed crystal ratio tends to be difficult to obtain a material having good crystallinity, the life of the light emitting element tends to be shortened when a nitride-based compound semiconductor containing Al is used as an active layer. However, in the light emitting element that emits high output in the ultraviolet region, the output of the light emitting element is dramatically improved only by adding a small amount of In to the GaN active layer. Then, the output is improved 10 times or more as compared with GaN. Therefore, both the α and δ values of InαGa ₁ -αN and InδGa ₁ -δN are adjusted to 0.1 or less, preferably 0.05 or less, more preferably 0.02 or less, and most preferably 0.01 or less. Here, InGaN does not include Al at all but also includes Al at an impurity level (for example, a state where the Al content is smaller than that of In) caused by diffusion or the like.

Further, the light emitting device used in the present invention is:
A nitride-based compound semiconductor of Al _x Ga ₁ -xN (0 <X ≦ 0.4) may be provided in contact with the active layer containing InαGa ₁ -αN and InδGa ₁ -δN. This Al _X Ga _1-X
The N layer only needs to be in contact with one of the two main surfaces of the active layer, and does not necessarily have to be in contact with both.
The X value of such Al _X Ga _1-X N is preferably in the range of 0 <X ≦ 0.4, more preferably in the range of 0 <X ≦ 0.2,
The range of 0 <X ≦ 0.1 is most preferable.

If it is larger than 0.4, cracks tend to be easily formed in the Al _x Ga ₁ -xN layer. When a crack is formed, it tends to be difficult to form an element structure by laminating another semiconductor thereon. The film thickness of Al _x Ga ₁ -xN is 0.3.
The film is formed to a thickness of 5 μm or less, more preferably 0.3 μm or less, and most preferably 0.1 μm or less. 0.5 μm
Is exceeded, the Al _x Ga ₁ -xN
This is because cracks tend to be easily formed in the inside.

When a nitride-based compound semiconductor layer having an Al mixed crystal ratio in a specific range is formed in contact with both principal surfaces of the active layer, the thicknesses of the nitride-based compound semiconductor layers are different from each other. Is desirable. The output tended to be improved when the Al _x Ga ₁ -xN layer on the n-layer side was made thinner. The Al _x Ga ₁ -xN nitride compound semiconductors on the n-layer side and the p-layer side may have different Al mixed crystal ratios.

Further, Al_XGa_1-XN (0 <X ≦
0.4) from the active layer rather than the nitride-based compound semiconductor
In the remote position_sGa_1-sN (0 ≦ s <0.1, j>
s, m> s) or Al_tGa_1-tN (0 <t ≦ 0.
4) It can also have a nitride-based compound semiconductor
You. GaN is preferably used for this nitride-based semiconductor.
In addition, Al_XGa_1-XSame as N nitride compound semiconductor layer
If it is formed in either the n-layer or the p-layer
Good, it is not always necessary to form both. In
_sGa_1-sN or Al_tGa_1-tThe thickness of N is particularly limited
However, when forming on the n-layer side, 10 μm
m, more preferably 8 μm or less. one
On the other hand, when it is formed on the p layer side, it is formed thinner than on the n layer side.
Preferably 2 μm or less, more preferably 1 μm
m or less. In addition, In_sGa_{1 -s}N, young
Kuha Al_tGa_1-tN may be plural in the same conductive layer
No.

Further, at least one of the n-layer side and the p-layer side, a GaN layer having a small band gap energy and Al _u Ga _1-u N (0
It may have a nitride-based semiconductor layer having a superlattice structure in which <u ≦ 1) layers are stacked. Al _u Ga _1-u N is may be formed in contact with the active layer, or may be formed in a position away from the active layer. Preferably, it is formed at a position away from the active layer and formed as a cladding layer for confining carriers or a contact layer for forming an electrode. A plurality of Al _u Ga _1-u N may be present in the same conductive layer.

In the case of a super lattice structure, a GaN layer and an Al
_u Ga _1-u film thickness of the N layer is 100 angstroms or less, more preferably 70 angstroms or less, and most preferably adjusted to below 50 Angstroms. If the thickness is more than 100 Å, the thickness of each semiconductor layer constituting the superlattice layer exceeds the elastic strain limit, and a minute crack or crystal defect tends to easily enter the film. The lower limit of the film thickness is not particularly limited as long as it is 1 atom or more. When Al _u Ga _1-u N and a superlattice structure layer, as compared to the thicker film thickness, even cracks difficult to enter those high Al content. This is because the Al _u Ga _1-u N layer is grown with a thickness equal to or less than the elastic critical thickness. Furthermore, A
since it grow at the same temperature and l _u Ga _1-u N and GaN,
Easy to super lattice. On the other hand but must also change the growth atmosphere is InGaN, constitute a superlattice AlGaN and InGaN as compared to the case of making a superlattice layer between the Al _u Ga _1-u N and GaN difficult.

When a superlattice layer having a GaN layer and an Al _u Ga _1-u N layer forms a cladding layer as an optical confinement layer and a carrier confinement layer, nitriding having a larger band gap energy than the well layer of the active layer is performed. Compound semiconductors need to be grown. The nitride-based compound semiconductor layer having a large band gap energy is a nitride-based compound semiconductor having a high mixed crystal ratio of Al. When a nitride-based compound semiconductor having a high mixed crystal ratio of Al is grown as a thick film, cracks are easily formed and crystal growth is very difficult.

However, when the superlattice layer is used, even if the single layer constituting the superlattice layer is a layer having a somewhat higher Al mixed crystal ratio,
Since the film is grown with a thickness less than the elastic critical thickness, cracks are unlikely to occur. Therefore, a layer having a high Al mixed crystal ratio can be grown with good crystallinity, so that the effects of light confinement and carrier confinement can be enhanced, and the threshold voltage can be reduced for LDs and Vf (forward voltage) for LEDs.

Further, the superlattice layer is doped with an impurity that determines the conductivity type of the superlattice layer, and Al _u Ga _{1 -uN}
The layer and the GaN layer can be modulation doping with different n-type impurity concentrations. For example, the threshold voltage, Vf, and the like can be reduced by lowering the n-type impurity concentration of one layer, preferably in a state in which the impurity is not doped (undoped), and doping the other layer at a high concentration. This is because the presence of a layer with a low impurity concentration in the superlattice layer increases the mobility of that layer, and the presence of a layer with a high impurity concentration at the same time allows the superlattice to remain at a high carrier concentration. This is because a layer can be formed. A layer having a high carrier concentration and a high mobility is formed by the simultaneous existence of a layer having a low impurity concentration and a high mobility and a layer having a high impurity concentration and a high carrier concentration. Therefore, it is assumed that the threshold voltage and Vf decrease.

When a nitride-based compound semiconductor having a large band gap energy is doped with an impurity at a high concentration, a two-dimensional electron gas is generated between the high impurity concentration layer and the low impurity concentration layer by the modulation doping. It is assumed that the resistivity decreases due to the effect of the two-dimensional electron gas. For example, n
In a superlattice layer in which a nitride-based compound semiconductor with a large band gap doped with a p-type impurity and an undoped nitride-based compound semiconductor with a small band gap are stacked, n
At the heterojunction interface between the layer to which the p-type impurity is added and the undoped layer, the barrier layer side is depleted, and electrons (two-dimensional electron gas) accumulate at the interface near the thickness on the layer side having a small band gap.

Since the two-dimensional electron gas is formed on the side having the smaller band gap, the electrons are not scattered by impurities when traveling, so that the mobility of the electrons in the superlattice increases and the resistivity decreases. It is inferred that the p-side modulation dope is also affected by the two-dimensional hole gas. In the case of a p-layer, AlGaN has a higher resistivity than GaN. Therefore, the doping of p-type impurities into AlGaN in a larger amount lowers the resistivity, so that the substantial resistivity of the superlattice layer decreases. Therefore, when a light emitting device is manufactured, the threshold value tends to decrease. It is inferred. In addition, ohmic contact with the electrode is easily obtained by lowering the resistivity. Further, the series resistance in the film is reduced, and a light-emitting element having a low threshold voltage and low Vf can be obtained.

On the other hand, when the nitride-based compound semiconductor layer having a small bandgap energy is doped with impurities at a high concentration, the following effects are presumed. For example, A
When doped with Mg as a p-type impurity with the same amount l _u Ga _1-u N layer and the GaN layer, a large depth of the acceptor level of Mg in the Al _u Ga _1-u N layer, activation rate small. On the other hand, the depth of the acceptor level of the GaN layer is Al _u Ga _1-u
It is shallower than the N layer and has a higher Mg activation rate. For example, Mg
The 1 × 10 ²⁰ / cm ³ in the doped to the GaN 1 × 10 ¹⁸
/ Cm ³ , whereas Al _u G
With a _{1 -uN} , a carrier concentration of only about 1 × 10 ¹⁷ / cm ³ can be obtained.

Therefore, a superlattice layer is formed from Al _u Ga _{1 -u} N / GaN, and the GaN layer having a higher carrier concentration is doped with a larger amount of impurities. Thereby, a superlattice layer with a high carrier concentration is obtained. Moreover small carrier concentration of impurities in the tunneling because it superlattice structure Al _u Ga _1-u
Move through the N layer. Therefore, the carrier is substantially Al _u G
effect of a _1-u N layer is not received, Al _u Ga _1-u N layer acts as a high-cladding layer having a band gap energy.
Even if the nitride-based compound semiconductor layer having the smaller bandgap energy is doped with a large amount of impurities, it is very effective in lowering the threshold value of LD and LED. In this description, an example is described in which a superlattice is formed on the P-type layer side. However, a similar effect can be obtained when a superlattice is formed on the n-layer side.

Nitride with large band gap energy
When doping a large amount of n-type impurities into
Nitride-based compound semiconductor with large band gap energy
Is preferably 1 × 10¹⁷/cm^Three~ 1
× 10²⁰/cm^Three, More preferably 1 × 10¹⁸/cm^Three~ 5
× 10¹⁹/cm^ThreeRange. 1 × 10¹⁷/cm^ThreeLess than
Without it, the bandgap energy is reduced to nitride.
The difference from the compound semiconductor is reduced and the carrier concentration is increased.
Layer tends to be difficult to obtain. Also 1 × 10 ²⁰/cm^Three
If it is larger than this, the leakage current of the light emitting element itself increases,
There is a tendency. On the other hand, the band gap energy is small.
N-type impurity concentration of nitride-based compound semiconductors
Capping energy is higher than that of nitride-based compound semiconductors.
The smaller the better, the better, preferably 1/10 or less
Good. Most preferably undoped and most mobile
Although a layer with a high thickness can be obtained, the band gap is
Diffusion from the nitride-based compound semiconductor side with large energy
It is considered that there is an n-type impurity that is coming. Therefore, n
The amount of mold impurities is 1 × 10¹⁹/cm^ThreeThe following is desirable. n-type
Periodic table of Si, Ge, Se, S, O, etc. as impurities
Group IVB and VIB elements can be selected. Better
Preferably, Si, Ge, and S can be n-type impurities.
You. This effect is due to the large band gap energy of nitrogen.
Doped n-type impurities into the compound semiconductor layer
Compound with small band gap energy
The same applies when the semiconductor layer is heavily doped with n-type impurities.
You.

The case where the superlattice layer is preferably subjected to modulation doping with impurities has been described above. However, the impurity concentration of the nitride-based compound semiconductor layer having a large band gap energy is equal to that of the nitride-based compound semiconductor layer having a small band gap energy. You can also.

When the above-mentioned superlattice layer is formed on the p-side layer, the effect of the superlattice structure on the light emitting element is that the superlattice has n
The operation is the same as that of the side layer, but has the following operation in addition to the case where it is further formed on the n-layer side. That is, the p-type nitride-based compound semiconductor usually has a resistivity higher by two digits or more than the n-type nitride-based compound semiconductor. Therefore, when the superlattice layer is formed on the p-layer side, the decrease in Vf appears remarkably.

It is known that a nitride-based compound semiconductor is a semiconductor in which a p-type crystal is hardly obtained. There is known a technique of removing a hydrogen by annealing a nitride-based compound semiconductor layer doped with a p-type impurity to obtain a p-type crystal. However, even if the p-type is obtained, the resistivity may be several Ω · cm or more by simply annealing. Therefore, crystallinity is improved by using a p-type layer as a superlattice layer. As a result, the resistivity is reduced by one digit or more, so that Vf tends to decrease.

When the above-mentioned nitride compound semiconductor layer which is a superlattice layer is formed on the p-side layer, a nitride compound semiconductor layer having a large band gap energy and a nitride compound semiconductor layer having a small band gap energy are provided. And p
The impurity concentration of the mold is different, and the impurity concentration of one layer is increased and the impurity concentration of the other layer is decreased. Similarly to the n-side layer of the superlattice, the p-type impurity concentration of the nitride-based compound semiconductor layer having a larger bandgap energy is increased, and the p-type impurity concentration of the nitride-based compound semiconductor layer having a smaller bandgap energy is increased. When the concentration is low, preferably undoped, the threshold voltage, Vf, and the like can be reduced. The reverse is also possible. That is, the p-type impurity concentration of the nitride-based compound semiconductor layer having a large band gap energy may be reduced, and the p-type impurity concentration of the nitride-based compound semiconductor layer having a small band gap energy may be increased. The reason is as described above.

In the case of forming a superlattice layer, p-type impurities are preferably used.
1 × 10¹⁸/cm ^Three~ 1 × 10^{twenty one}/ C
m^Three, More preferably 5 × 10¹⁸/cm^Three~ 5 × 10²⁰/ C
m^ThreeRange. 1 × 10¹⁸/cm^ThreeLess than the other
The difference from the nitride-based compound semiconductor layer of
It tends to be difficult to obtain a layer having a high rear concentration. Also,
1 × 10^{twenty one}/cm^ThreeIf more, the crystallinity tends to worsen
is there. On the other hand, nitrides with small bandgap energy
The p-type impurity concentration of the base compound semiconductor is
If the energy is less than that of the nitride-based compound semiconductor,
Good, preferably 1/10 or less. Most
Also preferably, when undoped, the layer having the highest mobility is
Can be obtained, but the band gap energy
P diffuses from the nitride-based compound semiconductor side
The amount of the p-type impurity is 1 × 10
²⁰/cm^ThreeThe following is desirable. Mg, Z as p-type impurities
Elements of Group IIA and IIB of the periodic table such as n, Ca, Be, etc. are preferred.
More preferably, it is Mg, Ca or the like. This effect
Is a nitride compound with a large band gap energy
The semiconductor layer is doped with a small amount of P-type impurities to form a bandgap.
P-type nitride-based compound semiconductor layer with low energy
The same applies to the case where many impurities are doped.

In the nitride-based compound semiconductor constituting the superlattice, the layer in which impurities are doped at a high concentration has a high impurity concentration near the center of the semiconductor layer and a low impurity concentration near both ends in the thickness direction ( More preferably, it is undoped. Specifically, S as an n-type impurity
When a superlattice layer is formed of i-doped AlGaN and an undoped GaN layer, AlGaN emits electrons to the conduction band as a donor because AlGaN is doped with Si. drop down. GaN
Since the crystal is not doped with donor impurities, carriers are not scattered by the impurities. Therefore, electrons can easily move in the GaN crystal, and the mobility of electrons is substantially increased. This is similar to the effect of the two-dimensional electron gas described above, and the electron mobility in the lateral direction is substantially increased, and the resistivity is reduced. Further, when the central region of AlGaN having a large band gap energy is doped with an n-type impurity at a high concentration, the effect is further enhanced. That is, Ga
Some of the electrons moving in N are scattered by n-type impurity ions (Si in this case) contained in AlGaN. However, if both ends are undoped in the thickness direction of the AlGaN layer, the scattering of Si becomes difficult, so that the mobility of the undoped GaN layer is further improved. Although the effect is slightly different, a similar effect is obtained when a superlattice is formed by a nitride-based compound semiconductor having a large bandgap energy on the p-layer side and a nitride-based compound semiconductor having a small bandgap energy. It is desirable that the central region of a large nitride-based compound semiconductor be heavily doped with p-type impurities to reduce both ends or be undoped. on the other hand,
A layer in which a nitride-based compound semiconductor having a small band gap energy is heavily doped with an n-type impurity may have the above-described impurity concentration.

In the case of a light emitting element using an insulating substrate, a part of the insulating substrate is removed or p
Exposed surfaces of the p-type semiconductor and the n-type semiconductor are formed by etching or the like, respectively, in order to obtain electrode surfaces for the mold and the n-type. Each electrode having a desired shape is formed on each semiconductor layer using Au, Al, or an alloy thereof by a sputtering method, a vacuum evaporation method, or the like. The electrode provided on the light emitting surface side is patterned so as to surround the light emitting region without covering the whole,
Alternatively, a transparent electrode such as a metal thin film or a metal oxide can be used. In addition, as an electrode material which can obtain a preferable ohmic with p-type GaN, Ni, Pt, Pd, Ni /
Au, Pt / Au, Pd / Au and the like can be suitably mentioned. Examples of electrode materials that can obtain n-type GaN and preferable ohmics include Al, Ti, W, Cu, Zn, Sn, and I.
Metals or alloys such as n can be suitably mentioned. The light emitting element thus formed can be used as it is, or may be divided into individual elements and used as a configuration such as an LED chip or an LD element.

When used as an LED chip or an LD element, the formed semiconductor wafer or the like is directly full-cut by a dicing saw in which a blade having a diamond blade is rotated, or a groove having a width wider than the blade width is formed. After cutting (half cut), the semiconductor wafer is broken by an external force. Alternatively, an extremely thin scribe line (meridian) is drawn on the semiconductor wafer, for example, in a checkerboard pattern by a scriber in which a diamond needle at the tip reciprocates linearly, and then the wafer is cut by an external force and cut into chips from the semiconductor wafer. Thus, a light-emitting element such as an LED chip which is a gallium nitride-based compound semiconductor can be formed.

In the case where the light emitting device of the present invention emits light of a color including red light, the main light emitting wavelength of the light emitting element is preferably 365 nm or more and 530 nm or less in consideration of efficiency.
It is preferably from 365 nm to 490 nm. When only red light is emitted, 365 nm which is mainly in the ultraviolet region
It is more preferably at least 400 nm. In addition, in consideration of deterioration of a resin member used for a light emitting element, a complementary color relationship with a fluorescent substance such as a white color, or the like, the wavelength is preferably 400 nm or more and 530 nm or less, and is 420 nm or more and 490 n.
m or less is more preferable. In order to further improve the efficiency of the LED chip and the fluorescent substance using visible light, the wavelength is more preferably 430 nm or more and 475 nm or less.
FIG. 5 shows an example of an emission spectrum when the present invention is used as a white light emitting device. Light emission having a peak around 450 nm is light emission from the LED chip, and 655.
The emission having a peak near nm is the emission of the fluorescent substance excited by the LED chip.

(The conductive wires 103, 203, 30
3) Conductive wires 103 and 20 as electrical connection members
As the layers 3 and 303, those having good ohmic properties, mechanical connectivity, electrical conductivity, and thermal conductivity with the electrodes of the light emitting elements 102, 202, and 302, such as LED chips, are required. 0.01 cal / c as thermal conductivity
m ² / cm / ° C. or more, more preferably 0.5
cal / cm ² / cm / ° C. or more. Further, in consideration of workability and the like, the diameter of the conductive wire is preferably Φ
10 μm or more and Φ45 μm or less. Specific examples of such conductive wires include conductive wires using metals such as gold, copper, platinum, and aluminum and alloys thereof. Such a conductive wire is connected to each LED
The electrode of the chip, the inner lead, the mount lead, and the like can be easily connected by a wire bonding device.

(Mount Lead 105) The mount lead 105 is for mounting the light emitting element 102, and it is sufficient that the mount lead 105 is large enough to be mounted on a die bonding device or the like. Further, when a plurality of light emitting elements are provided and the mount lead is used as a common electrode of the light emitting element, sufficient electric conductivity and connectivity with a bonding wire or the like are required. Further, in the case where the light emitting element is arranged in the cup on the mount lead and the fluorescent substance is filled therein, it is possible to prevent the pseudo light from being lit by light from another light emitting diode arranged in the vicinity. .

When ultraviolet light from a light emitting element is reflected by using a cup of a mount lead, ultraviolet light can be efficiently reflected by using silver as a surface material of the mount lead.

Light emitting device 102 and mount lead 105
Can be bonded with a thermosetting resin or the like. Specifically, an epoxy resin, an acrylic resin, an imide resin, SiO _2, or the like is used. In order to adhere to the mount leads and electrically connect them with a flip-chip type face-down LED chip or the like, Ag paste, carbon paste, ITO
A paste, a metal bump, or the like can be used. Further, in order to improve the light use efficiency of the light emitting diode, L
The surface of the mount lead on which the ED chip is arranged may be mirror-like, and the surface may have a reflection function. In this case, the surface roughness is preferably 0.1S or more and 0.8S or less. The specific electrical resistance of the mount lead is 30
0 μΩ · cm or less, more preferably 3 μΩ
-Cm or less. When a plurality of light emitting elements are mounted on the mount lead, good heat conductivity is required because the amount of heat generated from the light emitting elements increases. ^{Specifically, 0.01cal / cm 2 / cm /} ℃ or more preferably preferably 0.5cal / cm ² / cm / ℃ above. Materials satisfying these conditions include iron, copper, copper with iron, copper with tin, ceramic with a metallized pattern, and aluminum, copper, iron, and the like plated with gold, silver, and the like.

(Inner Leads 106, 306) The inner leads 106, 306 serve to electrically connect the light emitting elements 102, 302 disposed on the mount leads 105 to the conductive wires 103 connected thereto. It is. In the case where a plurality of light emitting elements are provided on the mount lead, it is necessary that the conductive wires be arranged so as not to contact each other. Specifically, as the distance from the mount lead increases, the area of the end face of the inner lead to which wire bonding is performed can be increased to prevent contact of the conductive wire connected to the inner lead further away from the mount lead. it can. The roughness of the connection end face with the conductive wire is preferably 1.6S or more and 10S or less in consideration of adhesion. inner·
In order to form the tips of the leads into various shapes, the shape of the lead frame may be determined in advance by a mold and punched and formed, or after all the inner leads have been formed, the upper part of the inner leads may be formed. You may form by shaving a part. Further, after the inner lead is punched and formed, a desired end face area and end face height can be simultaneously formed by pressing from the end face direction.

The inner leads are required to have good connectivity and electrical conductivity with a conductive wire such as a bonding wire. The specific electric resistance is 3
00 μΩ · cm or less, more preferably 3 μΩ
-Cm or less. Materials satisfying these conditions include iron, copper, copper with iron, copper with tin, and aluminum, iron, and copper plated with copper, gold, and silver.

(Coating Parts 101 and 301) The coating parts 101 and 301 used in the present invention are provided on a mount lead cup or the like separately from the mold member 104, and at least partially emit light of the light emitting element. It preferably contains a fluorescent substance to be converted.
Specific materials for the coating part include epoxy resin,
A translucent resin having excellent weather resistance, such as urea resin and silicone, and a translucent inorganic member such as TiO ₂ and SiO ₂ are preferably used. Also in the case where an inorganic member such as glass is used for the coating portion, a material which can be formed at a low temperature in consideration of deterioration of the light emitting element is preferable. Further, a coloring pigment, a coloring dye and a diffusing agent may be contained together with the fluorescent substance of the present invention. The color can also be adjusted by using a coloring pigment or coloring dye. Further, by including a diffusing agent, the directivity angle can be further increased. As a specific diffusing agent, inorganic barium titanate, titanium oxide, aluminum oxide, silicon oxide and the like, and organic guanamine resin are preferably used.

(Mold member 104) Mold member 10
4 can be provided to protect the light emitting element 102, the conductive wire 103, the coating portion 101 containing a fluorescent substance, and the like from the outside according to the use application of the light emitting device. The mold member can be generally formed by using a resin, but if necessary, the component can be formed by a light-transmitting inorganic member such as glass which does not cause a bad influence on the light emitting element 102 or the conductive wire. Is also good. Further, by including a fluorescent substance in the coating portion, the viewing angle of light emitted from the light emitting element can be increased. However, by including a diffusing agent in the mold member, the directivity from the light emitting element 102 can be relaxed. The corners can be further increased. In the case of a fluorescent substance that emits light by being excited by visible light, reflected light excluding the excitation wavelength is observed because the excitation wavelength is absorbed. Therefore, the fluorescent material looks colored. Specifically, the fluorescent substance excited by blue light according to the present invention appears to be colored yellow. By including a diffusing agent in the mold member, the body color of the fluorescent substance observed from the emission observation surface side of the light emitting device can be made less noticeable.

Further, it is possible to prevent color unevenness at the time of non-lighting and improve the contrast. Further, since the external light is less likely to be directly irradiated, an effect of preventing the observation of the pseudo lighting is also exerted. Similarly to the coating member, a coloring pigment or a coloring dye can be contained in the mold member.

By forming the mold member 104 into a desired shape, it is possible to provide a lens effect of converging or diffusing light emitted from the light emitting element 102. Therefore, the mold member 104 may have a laminated structure. Specifically, the shape is a convex lens shape, a concave lens shape, an elliptical shape when viewed from the light emission observation surface side, or a combination of a plurality of shapes. As a specific material of the mold member 104, a transparent resin having excellent weather resistance, such as an epoxy resin, a urea resin, or silicone, or a low-melting glass is preferably used. As the diffusing agent, inorganic barium titanate, titanium oxide, aluminum oxide,
Silicon oxide or the like or an organic guanamine resin is preferably used. Further, if desired, in addition to the diffusing agent, a fluorescent substance, a fluorescent dye, a fluorescent pigment, or the like can be contained in the mold member. Therefore, the fluorescent substance or the like may be contained in the mold member or may be contained in the other coating portion or the like. Alternatively, the coating portion may be formed using a different material such as a resin containing a fluorescent substance and the mold member using glass or the like. In this case, a light emitting device with high productivity and less influence of moisture or the like can be obtained. Further, the mold member and the coating portion may be formed using the same member in consideration of the refractive index.

When a can-type light emitting diode as shown in FIG. 3 is formed, a mold member to be a light-transmitting member, which is a low-melting glass, and a package formed of Au or Ag-plated Kovar are used to form Ar, It can be purged with N ₂ or the like and hermetically sealed.

(High-Definition Full-Color Light-Emitting Device) By using the present invention, a high-density full-color light-emitting device that can be used in a virtual image forming apparatus as shown in FIG. 4 can be obtained. B (blue), G (green) or GB (blue and green)
A plurality of separated light emitting elements are formed on a semiconductor wafer 401 capable of emitting light through etching, an insulating layer, and the like.

In order to separate the light emitting elements, the light emitting elements are also RG.
In order to cope with B, an etching portion, a high-resistance region such as an oxide or a nitride, and a separation portion 402 such as a semiconductor region having an opposite conductivity type are formed on a semiconductor wafer, so that adjacent light-emitting portions can be formed. Can be electrically and optically separated. Thus, the separating unit 402
Can be easily formed by adding a semiconductor process after forming a semiconductor wafer.

Specifically, by forming a high resistance region or a region of the opposite conductivity type into a desired shape such as an annular shape, the flow of current in the region is controlled and the light emitting portion is electrically separated from the surroundings. is there.

The buffer layer 404 and the first
Contact layer 405, a first cladding layer 406, an active region 407, a second cladding layer 408, and a second contact layer 309 are sequentially formed. In order to form light emitting portions separated from each other on a semiconductor wafer, a separating portion 402 in which a dopant having an opposite conductivity type to that of the second contact layer is implanted is formed in the second contact layer.

By arranging the coating portions 410 and 411 containing the light from the plurality of separated light emitting elements and the fluorescent substance excited by the light emitting elements, a full color high definition light emitting device capable of emitting RGB light is provided. It can be formed.

The semiconductor wafer for emitting monochromatic light used in the present invention comprises a buffer layer, a first contact layer, a first cladding layer, a first single quantum well or a multiple quantum well structure on a substrate. A semiconductor wafer having an active layer, a second cladding layer, and a second contact layer in that order and having electrodes provided on the first and second contact layers, respectively, can be used. Monochromatic light can be emitted by forming electrodes on the first and second contact layers of the semiconductor wafer and supplying power thereto.

Further, in order to form a semiconductor wafer capable of emitting blue or green light, respectively, the light emitting layer may have a multilayer structure. More specifically, a third contact layer, a third cladding layer,
A second active layer, a fourth cladding layer, and a fourth contact layer, which are active layers having a single quantum well structure or a multiple quantum well structure and have a composition different from that of the first active layer, are sequentially formed. The semiconductor wafer can be a semiconductor wafer capable of emitting multicolor light by using a semiconductor wafer provided with electrodes on the first, second, third, and fourth contact layers via through holes or the like. In this case, the band gap of the active layer closer to the light emitting portion is made narrower than the band gap of the farther active layer in consideration of absorption of emitted light.

Further, even if the light emitting section is separated, the light emitted from the light emitting section is radially emitted. For this reason, light emitted from one light-emitting portion may enter another light-emitting portion or another fluorescent substance region, and may cause a pseudo-lighting phenomenon in which the other light-emitting portion appears to emit light. It is more preferable to provide the light-shielding portion 413 in order to prevent or reduce the pseudo lighting phenomenon occurring between the adjacent light-emitting portions. The light-shielding portion 413 is made of a resin mixed with a reflective material such as a dark colorant or silicon oxide in a desired shape surrounding the light-emitting region of each light-emitting portion on a surface of a semiconductor wafer or the like by using a screen printing method or the like. In the light shielding part 413
Can be formed.

The fluorescent substance may be directly applied on the light emitting element and disposed, or a light-transmitting material such as glass, plastic, quartz, or the like in which a plurality of individual regions containing the fluorescent substance are formed. The member may be arranged close to the light emitting element. Further, a plurality of regions can be individually formed and used on a light-transmitting substrate on which a semiconductor is formed, such as a sapphire substrate or a spinel substrate.

In the case of a full-color light emitting device using a semiconductor wafer capable of emitting blue light, a fluorescent material emits green light excited by light from the light emitting portion for each pixel, and another fluorescent material emits green light. The fluorescent substance that emits reddish light used in the present invention and is excited by the light from the part can be selected. Since the light emitted from the light emitting element 102 emits blue light, the blue region of the semiconductor wafer is configured to transmit blue light as it is. The green and / or red light that is color-converted by the fluorescent substance has a wider viewing angle than the blue light because it is scattered by the fluorescent substance. Therefore, RGB
A light emitting material containing a diffusing agent and / or a colorant may be formed on the surface where blue light is emitted in order to make the light emitting characteristics of the light emitting device uniform and emit light with good color mixture. In addition, by making the light-emitting part somewhat larger than the light-emitting part using the fluorescent substance, the light finally emitted from the upper surface of the translucent substrate on which the fluorescent substance is arranged is almost uniformly in each region. It can also emit light.

Further, it is desirable that the light-shielding portion 413 contains a dark dye and / or pigment for preventing false lighting and improving contrast. The multicolor and high-definition light-emitting device using the light-emitting device of the present invention can be miniaturized and has good heat dissipation. In addition, a multicolor light-emitting device in which characteristic shifts due to temperature in both RGB emission colors are extremely small can be provided.

In such a light emitting device, the diameter of each light emitting portion can be set to about 20 μm or less, and the distance between the centers of the light emitting sections can be set to about 45 μm or less. Therefore,
A light-emitting device including nearly 10,000 light-emitting portions can also be formed. The light-emitting device may be electrically connected to a silicon integrated circuit on which a drive circuit and the like are formed so as to be integrally driven. This makes relatively inexpensive and high-definition LEDs
An LED display device with less color unevenness depending on the display device and the viewing angle can be provided.

(Display Device) A light-emitting device capable of emitting white light using the light-emitting device of the present invention can be used as a high color rendering LED display. That is, white display can be performed with higher definition than an LED display using only a combination of light emitting diodes that respectively emit RGB light. In order to display a white color or the like in a mixed color by combining the respective light emitting diodes, it is inevitable that the respective light emitting diodes of RGB simultaneously emit light. Therefore, the display per pixel is larger than that in the case of displaying each of the red, green and blue colors. Therefore, in the case of white display, it is not possible to display with higher definition compared to the RGB single color display. In addition, in order to display a white display by adjusting each light emitting diode, various adjustments must be made in consideration of the temperature characteristics of each semiconductor. further,
Since the display is based on mixed colors, the RGB light-emitting diodes may be partially shielded and the display color may be changed depending on the direction and angle of viewing of the LED display.

By using the light emitting device capable of emitting white light using the present invention in addition to the RGB light emitting diodes, higher definition can be achieved. In addition, white light emission can be stabilized and color unevenness can be eliminated. Further, luminance can be improved by emitting light from each of the RGB light emitting diodes. Specifically, a light emitting diode capable of emitting white light was formed using a light emitting diode in which a cerium-activated yttrium / aluminum / garnet fluorescent material was mixed in addition to the fluorescent material used in the present invention. By arranging the LED chip and the fluorescent substance in the cup, even when a plurality of light emitting diodes are arranged close to each other, it is possible to prevent the fluorescent substance from being excited by light from the other light emitting diode and being simulated. . Further, since the uneven light emission of the LED chip itself can be dispersed by the fluorescent substance, a light emitting diode which emits more uniform light can be obtained. Further, a light emitting device capable of emitting an arbitrary white light having a stronger reddish component can be provided.

An LED display device can be constructed by including such an LED display device in which two or more light emitting diodes of the present invention are arranged, and a drive circuit electrically connected to the LED display device. Specifically, as one of display devices using light emitting diodes capable of emitting white light, a white light emitting diode is used as one picture element in addition to each of the RGB light emitting diodes, and an arbitrary sign such as a sign or a matrix is used. A schematic configuration of an LED display arranged in a shape will be described. The LED display is electrically connected to a driving circuit, such as a lighting circuit. A display or the like capable of displaying various images by an output pulse from the drive circuit can be provided. A RAM (Random, Access, Memory) for temporarily storing input display data as a drive circuit
And a gradation control circuit for calculating a gradation signal for lighting each light emitting diode to a predetermined brightness from data stored in the RAM, and switching with the output signal of the gradation control circuit to switch each light emitting diode. And a driver for lighting. The gradation control circuit calculates a lighting time of the light emitting diode from data stored in the RAM and outputs a pulse signal. Here, when performing white display, the pulse signal of each of the RGB light emitting diodes is shortened, the pulse height is reduced, or no light is emitted. On the other hand, a pulse signal is output to the white light emitting diode so as to compensate for it.
Thereby, the white component of the LED display is displayed.

Therefore, it is preferable to separately provide a CPU as a gradation control circuit for calculating a pulse signal for lighting the white light emitting diode with desired luminance. The pulse signal output from the gradation control circuit is input to the driver of the white light emitting diode to switch the driver. The white light emitting diode is turned on when the driver is turned on, and is turned off when the driver is turned off.

Another LED display using the light emitting diode of the present invention will be described. An LED display device for black and white using only a light emitting diode capable of emitting white light using the present invention can be provided. _{Specifically, aMgO · bLi 2 O · Sb} 2 O utilized in activated yttrium-aluminum-garnet fluorescent material and the present invention with cerium
₃ : cMn, dMgO.eTiO ₂ : fMn, gMgO.
hMgF ₂ · GeO _2: to that is contained in at least one mixing coated member selected from IMN, a light emitting diode blue was utilized and capable of emitting light-emitting device.

An LED display for black and white can be configured by arranging only the light emitting diodes 701 of the present invention in a matrix or the like. Instead of the respective RGB driving circuits, the LED display can be configured as only the light emitting diode driving circuit of the present invention capable of emitting white light. L
The ED display is electrically connected to a driving circuit, such as a lighting circuit. A display or the like capable of displaying various images by an output pulse from the drive circuit can be provided.
The drive circuit includes a RAM (Random, Access, Mem) for temporarily storing input display data.
ory), a gradation control circuit for calculating a gradation signal for lighting the light emitting diode to a predetermined brightness from the data stored in the RAM, and switching with the output signal of the gradation control circuit to switch the light emitting diode. And a driver for lighting. The gradation control circuit calculates a lighting time of the light emitting diode from data stored in the RAM and outputs a pulse signal.

Therefore, the LED display for black and white is RG
Unlike the B full-color display, the circuit configuration can be simplified and the definition can be increased. Therefore, a display can be obtained at low cost without color unevenness due to the characteristics of the RGB light emitting diodes. Further, compared to the conventional LED display using only red and green, it is less irritating to human eyes and is suitable for long-time use.

(Surface Light Emitting Device) A surface light emitting device can be constructed as shown in FIG. 8 using the light emitting device of the present invention.

FIG. 8 shows a planar light emitting device having a light emitting element, a light guide plate optically joined to the light emitting element, and a color converter provided on at least one main surface of the light guide plate. In addition, at least the light-emitting portion of the light-emitting element is a gallium nitride-based compound semiconductor, and the color conversion portion is a translucent member containing at least one fluorescent substance used in the present invention. In the case of such a planar light emitting device, a fluorescent material is contained in the coating portion 808 and the scattering sheet 806 on the light guide plate. Alternatively, the scattering member 806 may be coated with a binder resin to form a sheet 801 and the mold member may be omitted. Specifically, the LED chip 802 is fixed in a U-shaped metal substrate 803 on which an insulating layer and a conductive pattern are formed. After establishing electrical continuity between the LED chip and the conductive pattern, a fluorescent substance is mixed and agitated with an epoxy resin, and a substrate 803 on which the LED chip 802 is mounted is mixed.
Coating part 80 filled on top and containing fluorescent material
A light emitting diode having 8 is formed. The light emitting diode thus formed is fixed to an end face of the acrylic light guide plate 804 with an epoxy resin or the like. On one main surface of the light guide plate 804, a film-like reflective layer 807 containing a white scattering agent for preventing color unevenness is arranged. Similarly, a reflection member 805 is provided on the entire rear surface side of the light guide plate and on the end surface on which the light emitting diode is not arranged to improve the light emission efficiency. Thus, a planar light source capable of obtaining sufficient brightness as an LCD backlight can be obtained. In particular, it is possible to provide a planar light-emitting device in which color unevenness and luminance decrease are extremely small even in a use environment where external light is irradiated in addition to light from a light-emitting element.

Further, a surface light emitting device capable of emitting white light is formed by using a coating portion in which a cerium-activated yttrium / aluminum / garnet fluorescent material is mixed in addition to the fluorescent material used in the present invention. When this planar light-emitting device is used as a full-color liquid crystal display device, a liquid crystal in which liquid crystal is injected between glass substrates having a light-transmitting conductive pattern (not shown) formed on the main surface of a light guide plate 804 is used. It can be configured by providing a polarizing plate provided via an apparatus. Hereinafter, examples of the present invention will be described, but it goes without saying that the present invention is not limited to only specific examples.

[0123]

【Example】

(Example 1) As a light-emitting device of the present invention, an LED chip arranged in a cup of a mount lead, an inner lead electrically connected to the LED chip by using a conductive wire, and filling in the cup A light emitting diode including the coated member, and a mold member covering at least a part of the coating member, the LED chip, the conductive wire, and the mount lead and the inner lead was formed.

The light emitting layer of the LED chip is at least a gallium nitride compound semiconductor and the active layer is In _0.05 Ga _0.95
N, and an LED chip having a main emission peak of 450 nm was used. In the LED chip, a TMG (trimethyl gallium) gas, a TMI (trimethyl indium) gas, a nitrogen gas, and a dopant gas are flowed together with a carrier gas on a cleaned sapphire substrate, and a gallium nitride-based compound semiconductor is formed by MOCVD. Formed.
It is formed by switching between SiH ₄ and Cp ₂ Mg as the dopant gas. An active layer of InGaN is formed between the contact layer and the cladding layer, which is a gallium nitride semiconductor having n-type conductivity, and the cladding layer, which is a gallium nitride semiconductor having p-type conductivity, to form a pn junction. Was. (Note that a gallium nitride semiconductor is formed at a low temperature on a sapphire substrate to serve as a buffer layer. The p-type semiconductor is annealed at 400 ° C. or higher after film formation.) The pn semiconductor surfaces are etched. After the exposure, each electrode was formed by sputtering. After a scribe line was drawn on the semiconductor wafer thus completed, the wafer was divided by external force to form LED chips as light emitting elements.

An LED chip was die-bonded to a mount lead having a cup at the tip of a silver-plated copper lead frame using an epoxy resin. Each electrode of the LED chip, the mount lead and the inner lead were each wire-bonded with a gold wire to establish electrical continuity.

On the other hand, the fluorescent substance is MgCO ₃ , Li ₂ CO
₃ , Sb ₂ O ₃ , and MnCO ₃ as raw materials in 5: 3:
1: Used in a molar ratio of 0.001 to 0.05. The respective oxides are sufficiently mixed using a ball mill or the like and packed in an alumina crucible or the like. The crucible is fired in air at a temperature of 1300 ° C. for about 2 hours, and further baked in an oxygen atmosphere at 560 ° C. for 10 hours.
After firing for a time, a fired product was obtained. The calcined product was ball-milled in methanol, washed, separated, dried, and finally passed through a sieve to form a Mg ₅ Li ₆ Sb ₂ O ₁₃ : Mn phosphor used in the present invention.

50 parts by weight of the formed Mg ₅ Li ₆ Sb ₂ O ₁₃ : Mn fluorescent substance and 100 parts by weight of the epoxy resin were mixed well to form a chiller. This chiller was injected into a cup on a mount lead on which an LED chip was placed. After the injection, the resin containing the fluorescent substance was cured at 130 ° C. for 1 hour. Thus, a thickness of about 13 on the LED chip
A coating portion was formed as a translucent member containing 0 μm of the fluorescent substance of the present invention. In the coating portion, the fluorescent substance is gradually increased toward the LED chip. Thereafter, a translucent epoxy resin was formed as a mold member for the purpose of further protecting the LED chip and the fluorescent substance from external stress, moisture, dust and the like. The mold member was cured at 150 ° C. for 5 hours after inserting a lead frame having a coating portion of a fluorescent substance formed in a shell type mold and injecting a translucent epoxy resin. When the light emitting diode thus formed was viewed from the front of the light emission observation, the center was colored yellowish due to the body color of the fluorescent substance.

When the chromaticity point of the light emitting diode which can emit light of the magenta color system thus obtained is measured, the chromaticity point (x =
0.251, y = 0.0088). The luminous efficiency was 7.4 lm / w. Further, as a weather resistance test, a current of 25 ° C. and 60 mA was applied,
In each test at a current of 20 mA at a temperature of 60 ° C. and 90% RH, no change due to the fluorescent substance was observed even after 500 hours.

Comparative Example 1 The fluorescent substance was 5MgO.3Li
_A light emitting diode was formed and a weather resistance test was performed in the same manner as in Example 1 except that a red fluorescent dye of a perylene derivative was used from ₂ O · Sb ₂ O ₅ . Immediately after energization, the formed light emitting diode was confirmed to emit magenta light in the same manner as in Example 1. In some weather resistance tests, the color tone changed within 24 hours and the output became zero. As a result of analyzing the cause of deterioration, the fluorescent substance was altered.

Example 2 5MgO.3Li ₂ O.Sb ₂
O ₅ : Mn fluorescent substance is changed from 50 parts by weight to 20 parts by weight;
(Y _0.6 Gd _0.4 ) ₃ Al ₅ O ₁₂ : Ce
100 light emitting diodes were formed in the same manner as in Example 1 except that 80 parts by weight of the fluorescent substance was added and mixed and stirred.

Incidentally, (Y _0.6 Gd _0.4 ) ₃ Al ₅ O ₁₂ : Ce
As a fluorescent substance, a solution obtained by dissolving rare earth elements of Y, Gd, and Ce in an stoichiometric ratio in an acid was coprecipitated with oxalic acid. This is mixed with a coprecipitated oxide obtained by calcination and aluminum oxide to obtain a mixed raw material. This was mixed with ammonium fluoride as a flux, packed in a crucible, and fired in air at a temperature of 1400 ° C. for 3 hours to obtain a fired product. The calcined product is ball-milled in water, washed, separated, dried, and finally formed through a sieve.

The chromaticity point, color temperature and color rendering index of the thus obtained light emitting diode capable of emitting white light were measured.
The chromaticity points (x = 0.296, y = 0.18, respectively)
3), color temperature 7090K, Ra (color rendering index) = 88.
5 is shown. Further, the light emission rate was 9.7 lm / W. Further, in the life test, an average of 100 formed light emitting diodes was performed. 5MgO ・ 3Li ₂ O ・
The color temperature and the color rendering of the light emitting diode formed in the same manner as in Example 1 except that the Sb ₂ O ₅ : Mn fluorescent substance was not added were respectively chromaticity points (x = 0.302, y = 0.280),
The color temperature was 8080 K and Ra (color rendering index) was 87.5, indicating that the light emitting diode of Example 2 was closer to the bulb color. 100% luminous intensity before life test
After 500 hours, the average luminous intensity was examined. It was 98.4% after the life test, and it was confirmed that there was no difference in characteristics.

Example 3 A light emitting diode of the present invention was used for a display which is a kind of LED display as shown in FIG. A light emitting diode was formed in the same manner as in Example 2 except that a mold member containing a guanamine resin as a diffusing agent in an epoxy resin at about 0.1% by weight was used. The light emitting diodes were arranged in a 16 × 16 matrix on a glass epoxy resin substrate on which a copper pattern was formed. The substrate and the light emitting diode were soldered using an automatic solder mounting device. Next, it was arranged and fixed inside the housing 704 formed of a phenol resin. The light blocking member 705 is formed integrally with the housing. Except for the tip of the light emitting diode, a part of the housing, the light emitting diode, the substrate, and the light shielding member was filled with silicon rubber 706 colored black with a pigment. Then, at room temperature, 72
The silicone rubber was cured over time to form an LED display. This LED display and a RAM (Random, Access,
Memory) and a gradation control circuit for calculating a gradation signal for lighting the light emitting diode to a predetermined brightness from the data stored in the RAM, and a driver for lighting the light emitting diode by being switched by an output signal of the gradation control circuit. An LED display device was constructed by electrically connecting the CPU driving means having the following. It was confirmed that the LED display was driven to be able to be driven as a monochrome LED display.

Example 4 The active layer was formed of In as a light emitting element.
_0.4 Ga _0.6 N semiconductor with a main emission peak of 460 nm
LED chips were used. The LED chip is made of TMG (trimethyl gallium) gas on a cleaned sapphire substrate.
MOCVD by flowing TMI (trimethyl indium) gas, nitrogen gas and dopant gas together with carrier gas
The gallium nitride-based compound semiconductor was formed by a film forming method. SiH ₄ and Cp ₂ M as dopant gas
and g. An active layer of In _0.4 Ga _0.6 N is formed between a contact layer, which is a gallium nitride semiconductor having n-type conductivity, a cladding layer, which is a gallium nitride semiconductor having p-type conductivity, and a pn junction. I let it. (Note that a gallium nitride semiconductor is formed on a sapphire substrate at a low temperature to serve as a buffer layer. The active layer has a thickness of about 3 nm so as to have a quantum effect. After the film, it was annealed at 400 ° C. or higher.) After exposing each pn semiconductor surface by etching, each electrode was formed by sputtering. After a scribe line was drawn on the semiconductor wafer thus completed, the wafer was divided by external force to form LED chips as light emitting elements.

An LED chip was die-bonded to a mount lead having a cup at the tip of a silver-plated copper lead frame using an epoxy resin. Each electrode of the LED chip, the mount lead and the inner lead were each wire-bonded with a gold wire to establish electrical continuity.

On the other hand, the fluorescent substances are MgCO ₃ , TiO ₂ ,
MnCO ₃ as raw material, 2: 1: 0.001-
Used at a molar ratio of 0.05. The respective oxides are sufficiently mixed using a ball mill or the like and packed in an alumina crucible or the like. The crucible was fired in air at a temperature of 1350 ° C. for about 2 hours, and further fired in an oxygen atmosphere at 560 ° C. for 10 hours to obtain a fired product. The calcined product was ball-milled in methanol, washed, separated, dried, and finally passed through a sieve to form the Mg ₂ TiO ₄ : Mn phosphor used in the present invention.

In addition, (Y _0.6 Gd _0.4 ) ₃ Al ₅ O ₁₂ : Ce
A solution in which rare earth elements of Y, Gd, and Ce were dissolved in an acid at a stoichiometric ratio as a fluorescent substance was coprecipitated with oxalic acid. This is mixed with a coprecipitated oxide obtained by calcination and aluminum oxide to obtain a mixed raw material. This was mixed with ammonium fluoride as a flux, packed in a crucible, and placed in air at 1400 °.
C. for 3 hours to obtain a baked product. The calcined product is ball-milled in water, washed, separated, dried, and finally formed through a sieve.

Formed Mg ₂ TiO ₄ : Mn phosphor 2
5 parts by weight, 60 parts by weight of (Y _0.6 Gd _0.4 ) ₃ Al ₅ O ₁₂ : Ce phosphor, and 100 parts by weight of epoxy resin were mixed well to form a chiller. This chiller was injected into a cup on a mount lead on which an LED chip was placed. After the injection, the resin containing the fluorescent substance was cured at 130 ° C. for 1 hour. In this way, a coating portion containing a fluorescent substance having a thickness of about 120 μ was formed on the LED chip. In the coating portion, the fluorescent substance is gradually increased toward the LED chip. Thereafter, a translucent epoxy resin was formed as a mold member for the purpose of further protecting the LED chip and the fluorescent substance from external stress, moisture, dust and the like. The mold member was cured at 150 ° C. for 5 hours after inserting a lead frame on which a fluorescent material coating was formed into a shell type mold, mixing a light-transmitting epoxy resin. When the light emitting diode thus formed was viewed from the front of the light emission observation, the center was colored yellowish due to the body color of the fluorescent substance.

It was confirmed that the light-emitting diode thus obtained can be used as a light-emitting diode capable of emitting white light, as in Example 2.

(Example 5) The phosphor substance was made of Mg ₂ TiO ₄ :
3.5MgO from _{Mn · 0.5MgF 2 · GeO 2:} Mn
A light emitting diode was formed in the same manner as in Example 4 except that the above conditions were satisfied. It was confirmed that the red light emitting diode can be used as a light emitting diode capable of emitting light as in Example 4.

(Example 6) As a light emitting element, the active layer was In.
L is _0.01 Ga _0.99 N and has a main emission peak of 368 nm.
An ED chip was used. The LED chip is made of TMG (trimethyl gallium) gas, T
An MI (trimethyl indium) gas, a nitrogen gas and a dopant gas were flowed together with a carrier gas, and a gallium nitride-based compound semiconductor was formed by MOCVD. SiH ₄ and Cp ₂ Mg as dopant gas
And by switching between them. A buffer layer of a gallium nitride semiconductor formed on a sapphire substrate at a low temperature, a contact layer of a gallium nitride semiconductor having n conductivity, a cladding layer of a gallium aluminum nitride semiconductor having n type conductivity, and a p type conductivity InGa between the cladding layer, which is a gallium aluminum nitride semiconductor having conductivity, and a contact layer having p-type conductivity.
An N active layer was formed to form a pn junction. (Note that p
The type contact layer is provided with a low impurity concentration gallium nitride layer on the p-type cladding layer and a high impurity concentration gallium nitride layer in contact with the electrode so that Mg as an impurity is not diffused on the active layer side. is there. Further, the active layer is grown to a thickness of 400 Å. The semiconductor having P-type conductivity is annealed at 400 ° C. or higher after film formation. After exposing each pn semiconductor surface by etching, each electrode was formed by sputtering. After a scribe line was drawn on the semiconductor wafer thus completed, the wafer was divided by external force to form LED chips as light emitting elements.

An LED chip was die-bonded with an epoxy resin to a mount lead having a cup at the tip of a silver-plated copper lead frame. Each electrode of the LED chip, the mount lead and the inner lead were each wire-bonded with a gold wire to establish electrical continuity.

On the other hand, the fluorescent substances are MgCO ₃ , GeO ₂ ,
MnCO ₃ as raw material, 3.5: 0.5: 1:
It is used in a molar ratio of 0.001 to 0.05. The respective oxides are sufficiently mixed using a ball mill or the like and packed in an alumina crucible or the like. The crucible was fired in air at 1200 ° C. for about 2 hours, and further fired in an oxygen atmosphere at 560 ° C. for 10 hours to obtain a fired product. Washed calcined product is ball in water, separation, drying, finally used in the present invention through a sieve to 3.5MgO · 0.5MgF ₂ · GeO _2: to form a Mn phosphor.

3.5MgO.0.5MgF ₂ .GeO ₂ :
50 parts by weight of Mn phosphor was placed in a cup on the mount lead. The fluorescent substance is made of TiO ₂ using the sol-gel method.
Trapped in layers. Thus, a coating portion containing a fluorescent substance was formed on the LED chip. Thereafter, to protect the LED chip and the fluorescent substance from external stress, moisture, dust, etc., a can-type light emitting diode was formed in which a glass lens was fitted in a metal frame while being insulated from each lead and purged with N ₂ .

The light emitting diode thus obtained was able to emit red light. Further, as a weather resistance test, the temperature is 25 ° C
60mA current, temperature 25 ° C, 20mA current, temperature 60 ° C9
No change due to the fluorescent substance was observed in each of the tests at 20 mA under 0% RH and after 500 hours.

(Example 7) The phosphor substance was 3.5 MgO
0.5MgF_Two・ GeO_Two: Mn to Y (PV) O _Four: E
A light emitting diode was manufactured in the same manner as in Example 6 except that
Formed. A light emitting device capable of emitting red light as in the sixth embodiment.
It was confirmed that it could be used as an ion.

(Embodiment 8) The phosphor material was 3.5 MgO
0.5MgF ₂ · GeO _2: YVO from Mn _4: was except that the Eu in the same manner as in Example 6 to form a light emitting diode. It was confirmed that the red light emitting diode can be used as a light emitting diode capable of emitting light in the same manner as in Example 6.

Example 9 A light emitting device was formed by the following steps. The surface of the sapphire substrate (C surface) is cleaned at 1050 ° C. in a hydrogen atmosphere in a reaction vessel. Subsequently, a low-temperature growth buffer layer made of GaN was formed on a sapphire substrate at about 510 ° C. in a hydrogen atmosphere at 510 ° C. for about 200 minutes.
It is grown to a thickness of Å. After growing the low temperature buffer layer, at 1050 ° C., using TMG and ammonia,
1 μm second buffer layer made of undoped GaN layer
It grows with the film thickness of.

At 1050 ° C., TMG, ammonia and silane (SiH ₄ ) were used as source gases,
^An n-side contact layer made of ¹⁸ / cm ³ doped n-type GaN is grown to a thickness of 2 μm.

At 1050 ° C., using TMG, TMA (trimethylaluminum) ammonia and silane, the n-side cladding layer is an undoped GaN layer, 50 Å, and Al _0.1 Ga _0.9 doped with 1 × 10 ¹⁸ / cm ^{3 of} Si.
It is grown as a superlattice structure having a total thickness of 300 Å by alternately laminating N layers with 50 Å.

TMI, TM at 700 ° C. in a nitrogen atmosphere
G, ammonia, and an n-type impurity concentration of 5 × 10 ¹⁷ /
An active layer made of non-doped In _0.05 Ga _0.95 N having a thickness of less than ³ cm ³ is grown to a thickness of 400 Å.

TMG, TM at 1050 ° C. in a hydrogen atmosphere
A, ammonia, Cp2Mg (cyclopentadienylmagnesium), undoped G on the p-side cladding layer
50 angstrom of aN layer and 1 × 10 ¹⁹ / cm of Mg
^It is grown as a superlattice structure having a total film thickness of 600 Å by alternately stacking 3 Å-doped Al _0.1 Ga _0.9 N layers and 50 Å.

Subsequently, TMG, ammonia, Cp2Mg
Then, a p-side contact layer made of GaN doped with 1 × 10 ²⁰ / cm ^{3 of} Mg is grown to a thickness of 0.12 μm.

After the growth is completed, the wafer is annealed in a reaction vessel in a nitrogen atmosphere at 700 ° C.
After further reducing the resistance of the mold layer, the wafer is taken out of the reaction vessel, a mask having a predetermined shape is formed on the surface of the uppermost p-side contact layer, and the RIE (reactive ion etching) apparatus is used to form the mask on the p-side contact layer side. Etching from
The surface of the n-side contact layer is exposed.

After the etching, almost 200 nm of a light-transmitting p-electrode containing Ni and Au is formed on almost the entire surface of the uppermost p-side contact layer, and a p-pad made of Au for bonding is formed on the p-electrode. An electrode is formed with a thickness of 0.2 μm. On the other hand, an n-electrode containing W and Al is formed on the surface of the n-type contact layer exposed by etching. Finally, after an insulating film made of SiO ₂ is formed to protect the surface of the p-electrode, the wafer is separated by scribing to obtain a light emitting device of 350 μm square. Forward voltage 2
At 0 mA, emission of about 378 nm was observed, and Vf
Indicates 3.3 V and the output is 5 mW.

On the other hand, as a fluorescent substance, Y_TwoO_TwoS: Eu firefly
A light substance was formed. As a forming condition, Y_TwoO_ThreeAnd Eu_Two
O_ThreeIs dissolved in hydrochloric acid and coprecipitated as nitrate. At this time
Eu _TwoO_ThreeThe amount is 10 mol%. This precipitate
It is baked at 900 ° C. in air to form an oxide. The resulting acid
Mixed with sulfur, sodium carbonate and flux
Place in a crucible and bake at 1100 ° C for 2 hours.
Get a product. The baked product is pulverized, washed, separated and dried, and finally
Y used in the present invention through a sieve_TwoO_TwoS: Eu fluorescent material
Formed quality. The peak wavelength of this fluorescent substance is 627 n
m.

A light emitting device was formed in the same manner as the light emitting device of Example 6, except that the above light emitting element and the Y ₂ O ₂ S: Eu phosphor were used. This light emitting device was able to emit red light with extremely high luminance.

Example 10 Example 9 was performed in the same manner as in Example 9 _except that the active layer was an In _0.05 Ga _0.95 N layer doped with 1 × 10 ¹⁸ / cm ³ of Si and having a thickness of 500 Å. When a light-emitting device was manufactured, the same light-emitting characteristics as in Example 9 were exhibited.

(Embodiment 11) In the ninth embodiment, the light-emitting device is the same as the light-emitting device, except that the n-side cladding layer is made of an undoped Al _0.1 Ga _0.9 N layer of 50 Å and a GaN layer of 1 × 10 ¹⁸ / cm ³ doped with Si of 50 Å. A superlattice structure having a total film thickness of 300 Å is formed by alternately laminating the layers, and the p-side cladding layer is made of undoped Al _0.1 Ga.
_0.9 N layer 50 Å and Mg 1 × 10 ¹⁹ / c
A superlattice structure having a total film thickness of 600 Å is formed by alternately laminating m ³ -doped GaN layers of 50 Å.

On the other hand, a Y ₂ O ₃ : Eu fluorescent substance was used as the fluorescent substance. For the formation, boron is added as a flux to Y ₂ O ₃ and Eu ₂ O ₃ and dry-mixed for 3 hours. The mixed raw material is fired in air at 1400 ° C. for about 6 hours to obtain a fired product. The fired product was dispersed by milling in a wet system, and washed, dispersed, dried, and dried through a sieve to form a Y ₂ O ₃ : Eu phosphor used in the present invention. The peak wavelength of this fluorescent substance was 611 nm. The above light emitting element and Y ₂
A light emitting device was formed in the same manner as the light emitting device of Example 9 except that O ₃ : Eu fluorescent material was used. This light emitting device was also able to emit red light with extremely high luminance.

(Example 12) As the light emitting element, the active layer was I
An LD device having n _0.05 Ga _0.95 N and a main emission peak of 368 nm was used.

On a sapphire substrate, a low-temperature growth buffer layer made of GaN, a second buffer layer made of an undoped GaN layer, and a stripe width of 2 on the surface of the second buffer layer.
A protective film made of SiO ₂ having a thickness of 0.1 μm and a stripe of GaN having a thickness of 0.1 μm and a stripe interval (window) of 5 μm
(11-00) direction. After forming the protective film, a GaN layer made of undoped GaN is
A GaN substrate having a surface of GaN grown by a thickness of μm is formed. An n-side contact layer made of n-type GaN doped with 1 × 10 ¹⁸ / cm ³ or more of Si on a GaN substrate;
A crack preventing layer made of In _0.1 Ga _0.9 N doped with i at 5 × 10 ¹⁸ / cm ^3, and a layer made of n-type Al _0.2 Ga _0.8 N doped with 1 × 10 ¹⁹ / cm ³ at 40 Å. An undoped GaN layer is grown to a thickness of 40 angstroms, and an n-side cladding layer composed of a superlattice having a total thickness of 0.8 μm, in which 100 layers of these layers are alternately stacked, is grown.

Undoped Al_0.05Ga_0.95N consisting of N
Side light guide layer, undoped In_0.01Ga_0.99Consisting of N
Active layer, Mg 1 × 10¹⁹/cm^ThreeDoped p-type Al_0.2
Ga _0.8N-side p-side cap layer, Al_0.01Ga_0.99N
Is formed.

Next, a p-type Al _0.2 Ga _0.8 N layer doped with Mg at 1 × 10 ¹⁹ / cm ³ and undoped GaN alternately stacked at 40 Å were grown to a total thickness of 0.8 μm.
A p-side cladding layer having a superlattice structure is formed.

Finally, on the p-side cladding layer, Mg was added
A p-side contact layer made of p-type GaN doped with × 10 ²⁰ / cm ³ is formed.

After the wafer on which the nitride-based compound semiconductor has been grown as described above is annealed to further reduce the resistance of the layer doped with the p-type impurity, the uppermost p-side contact layer and the p-side Etch layers and
The layer above the active layer has a stripe-shaped ridge shape.

Next, the surface of the n-side contact layer is exposed, and an n-electrode made of Ti and Al is formed in a stripe shape. On the other hand, Ni and A are formed on the outermost surface of the ridge of the p-side contact layer.
A p-electrode made of u is formed in a stripe shape.

An insulating film made of SiO ₂ is formed on the surface of the nitride-based compound semiconductor exposed between the p-electrode and the n-electrode, and a p-pad electrode electrically connected to the p-electrode via the insulating film is formed. Form.

As described above, the wafer on which the n-electrode and the p-electrode are formed is transferred to a polishing apparatus, and the sapphire substrate on which the nitride-based compound semiconductor is not formed is wrapped, and the thickness of the sapphire substrate is reduced. 70 μm. After lapping, the surface of the substrate is mirror-finished by polishing with a finer abrasive at 1 μm, and the entire surface is metallized with Au / Sn.

Thereafter, the Au / Sn side is scribed,
Cleavage is performed in a bar shape in a direction perpendicular to the stripe-shaped electrodes, and a resonator is formed on the cleavage plane. SiO ₂ and TiO ₂ on the resonator surface
Finally, a bar is cut in a direction parallel to the p-electrode to form a laser chip. Next, the chip was placed on the heat sink face up (in a state where the substrate and the heat sink faced each other). The formed LD is
At room temperature, continuous oscillation with an oscillation wavelength of 368 nm was confirmed at a threshold current density of 2.0 kA / cm ² and a threshold voltage of 4.0 V.

Y ₂ O ₂ S obtained by applying an ultraviolet laser from such a light emitting element on a screen together with a binder:
It was optically connected so that the Eu fluorescent material could be irradiated. Light from a light emitting element that emits ultraviolet light is further condensed by a lens and projected on the screen. A desired image can be obtained by scanning the focused ultraviolet light with a deflecting mirror and screening. Also in this case, the fluorescent substance can emit light with high luminance without deterioration.

[0172]

According to the constitution of the present invention, a light emitting device of a nitride-based compound semiconductor having a high output and an aMgO.bLi
₂ O.Sb ₂ O ₃ : cMn, dMgO.eTiO ₂ : fM
_{n, gMgO · hMgF 2 · GeO} 2: iMn, jCaO
_{· KM1O · TiO 2: lPr,} mM2 2 O 3 · (P 1-n V
_n ) ₂ O ₅ : oEu ₂ O ₃ , M3 ₂ O ₂ S: pEu, M4 ₂ O:
By using a light emitting device using at least one kind of fluorescent substance selected from qEu, a relatively high-energy light emitted from a gallium nitride-based compound semiconductor can be efficiently converted by the fluorescent substance while maintaining high luminance and long time. A light-emitting device with high luminous efficiency, in which color unevenness and luminance decrease are extremely small even when used, can be obtained. Further, the fluorescent substance is excited by the short-wavelength excitation wavelength and emits light of a longer wavelength. Therefore, the light of the fluorescent substance is emitted from the light emitting device in proportion to the amount of light emitted from the light emitting element.

The present invention can be applied to a light emitting device including a light emitting component on a long wavelength side in a visible light region. Furthermore, new applications such as reliability, power saving, miniaturization, and color temperature variability can be opened as lighting in addition to display in the in-vehicle, aviation industry, and general electric devices. Further, when white is visually recognized by human eyes for a long time, a light-emitting device that is less stimulating and is gentle on the eyes can be provided.

In particular, the configuration according to any one of claims 1 to 5 of the present invention makes it possible to emit light having a red component, which has a very low luminance and a low color shift even when used for a long time with high luminance. Various possible light-emitting devices can be used.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a light emitting diode which is a light emitting device of the present invention.

FIG. 2 is a schematic sectional view of another light emitting device of the present invention.

FIG. 3 is a schematic sectional view of another light emitting device of the present invention.

FIG. 4 is a schematic sectional view of still another light emitting device of the present invention.

FIG. 5 is a diagram showing an example of an emission spectrum of Example 1 which is a light emitting device of the present invention.

FIG. 6 (A) shows an example of an excitation spectrum of the fluorescent substance used in Example 1 of the present invention, and FIG. 6 (B) shows an example of the fluorescent substance used in Example 1 of the present invention. FIG. 3 is a diagram showing an example of an emission spectrum.

FIG. 7 is a schematic diagram of an LED display device using the light emitting device of the present invention.

FIG. 8 is a schematic sectional view of a planar light emitting device using the light emitting device of the present invention.

FIG. 9 is a graph showing relative luminance with respect to a temperature change of a light emitting element in which A is a GaAsP light emitting layer and emits red light, and B is a temperature change of a light emitting element in which green light is emitted using InGaN as a light emitting layer; , Where C is InG
The relative luminance with respect to a temperature change of a light-emitting element capable of emitting blue light using aN as a light-emitting layer is shown.

[Explanation of symbols]

101, 301, 808 ... Coating part containing fluorescent substance 102, 202, 302, 802 ... Light emitting element 103, 203, 303 ... Conductive wire 104 ... Mold member 105, 305 ...・ Mount lead 106, 306 ・ ・ ・ Inner lead 201 ・ ・ ・ Mold member containing fluorescent substance 204 ・ ・ ・ Case 205 ・ ・ ・ Electrode provided on the case 304 ・ ・ ・ Transparent inorganic Low melting point glass 307: Package 308: Low melting point glass as insulating sealant 401: Semiconductor wafer 402: Opposite conductivity type region 403: Electrode 404: Buffer layer 405 ··· First contact layer 406 ··· First cladding layer 407 ··· Active layer 408 ··· Second cladding layer 409 ··· Contact layer 410: coating portion containing fluorescent material used in the present invention 411: coating portion containing another fluorescent material 413: light shielding portion 414: sapphire substrate 421 ... Insulating layer 422: Transparent electrode 701: Light emitting diode 704: Housing 705: Light shielding member 706: Filler 803: Metal substrate 804: Light guide plate 805: Reflection Member 806: scattering sheet 807: reflection layer

Claims (5)

[Claims] 1. A gallium nitride compound having at least a light emitting layer
A light emitting element which is a semiconductor and a light emitting wave emitted by the light emitting element
Fluorescence that absorbs at least part of its length, converts wavelength and emits light
A light-emitting device having a substance, wherein an emission spectrum from the light-emitting element has a main peak of 3
The fluorescent substance which is within 65 nm to 530 nm,
Is aMgO ・ bLi_TwoO ・ Sb_TwoO_Three: CMn, dMgO.eTiO_Two: FMn, gMgO.hMgF_Two・ GeO_Two: IMn, jCaO · kM1O · TiO_Two: LPr, mM2_TwoO_Three・ (P_1-nV_n)_TwoO_Five: OEu_TwoO_Three Characterized by at least one selected from
Light emitting device. However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.001
≤ c ≤ 0.05, 1 ≤ d ≤ 3, 1 ≤ e ≤ 2, 0.001 ≤ f ≤ 0.05, 2.5 ≤ g ≤ 4.0, 0 ≤ h ≤ 1, 0.003 ≤ i ≤
0.05,  M1 is at least selected from Zn, Mg, Sr and Ba.
Also one kind. j + k + 1 = 1, 0 <k ≦ 0.4, 0.000
01 ≦ l ≦ 0.2,  M2 is a small number selected from La, Y, Sc, Lu, and Gd.
At least one. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.0
01 ≦ o ≦ 0.5. 2. A light-emitting device in which a light-emitting layer is at least a nitride-based compound semiconductor and emits visible light, and a fluorescent substance which is excited by a visible light-emitting wavelength of the light-emitting device and emits fluorescence having a longer wavelength than the light-emitting wavelength. A light-emitting device, wherein the light-emitting element is a non-doped InαAlβGa _1- α _- βN layer having a double heterostructure between an n-type nitride-based compound semiconductor layer and a p-type nitride-based compound semiconductor layer. An active layer, wherein the α value of the InαAlβGa ₁ -α _- βN layer is 0 or more;
The value is 0 or more, the α + β value is less than 1, the thickness of the InαAlβGa ₁ -α _- βN layer is less than 100 angstroms, and the composition formula of the phosphor is aMgO.bLi ₂ O.Sb ₂ O ₃ : cMn; _{dMgO · eTiO 2: fMn, gMgO} · hMgF 2 · GeO 2: light-emitting device, characterized in that at least one selected from the IMN. However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.001
≤ c ≤ 0.05, 1 ≤ d ≤ 3, 1 ≤ e ≤ 2, 0.001 ≤ f ≤ 0.05, 2.5 ≤ g ≤ 4.0, 0 ≤ h ≤ 1, 0.003 ≤ i ≤
0.05. 3. A light-emitting device in which the light-emitting layer is at least a nitride-based compound semiconductor and emits visible light, and a fluorescent substance which is excited by the visible light-emitting wavelength of the light-emitting device and emits fluorescence having a longer wavelength than the light-emitting wavelength. A light emitting device, comprising: a light emitting element having a double hetero structure between a n-type nitride-based compound semiconductor layer and a p-type nitride-based compound semiconductor layer, the p-type impurity being InαAlβGa _1- α _- βN An active layer, wherein the α value of the InαAlβGa ₁ -α _- βN layer is 0 or more,
The value is 0 or more, the α + β value is less than 1, the thickness of the InαAlβGa ₁ -α _- βN layer is 100 Å or more, and the composition formula of the phosphor is aMgO.bLi ₂ O.Sb ₂ O ₃ : cMn; _{dMgO · eTiO 2: fMn, gMgO} · hMgF 2 · GeO 2: light-emitting device, characterized in that at least one selected from the IMN. However, 2 ≦ a ≦ 6, 2 ≦ b ≦ 4, 0.001
≤ c ≤ 0.05, 1 ≤ d ≤ 3, 1 ≤ e ≤ 2, 0.001 ≤ f ≤ 0.05, 2.5 ≤ g ≤ 4.0, 0 ≤ h ≤ 1, 0.003 ≤ i ≤
0.05. 4. A light emitting layer comprising at least a nitride compound semiconductor.
A light-emitting element that emits ultraviolet light, and an ultraviolet light of the light-emitting element.
Excited by the emission wavelength and emits fluorescence longer than the emission wavelength
A light-emitting device comprising: a light-emitting fluorescent material, wherein the light-emitting element is an n-type nitride-based compound semiconductor layer;
Double heterostructure between the nitride-based compound semiconductor layer
InαGa containing n-type impurities_1-Has αN active layer
And the n-type impurity concentration is 5 × 10¹⁷/ Cm^ThreeLess than the InαGa_1-α value of αN layer is larger than 0 and 0.1 or less
Below, the InαGa_1-αN layer thickness is 100 Å
Not less than 1000 Angstroms,
The composition formula of the fluorescent substance is gMgO.hMgF_Two・ GeO_Two: IMn, jCaO · kM1O · TiO_Two: LPr, mM2_TwoO_Three・ (P_1-nV_n)_TwoO_Five: OEu_TwoO_Three, M3_TwoO_TwoS: pEu, M4_TwoO: at least one selected from qEu
Light emitting device. However, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05,  M1 is at least selected from Zn, Mg, Sr and Ba.
Also one kind. j + k + 1 = 1, 0 <k ≦ 0.4, 0.000
01 ≦ l ≦ 0.2,  M2 is a small number selected from La, Y, Sc, Lu, and Gd.
At least one. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.0
01 ≦ o ≦ 0.5, M3 is a small number selected from La, Y, Ga, Sc, and Lu
At least one. 0.0005 ≦ p ≦ 0.1, M4 is at least one selected from La, Y, and Ga.
0.0005 ≦ q ≦ 0.1. 5. The light-emitting layer has at least a nitride-based compound semiconductor.
A light-emitting element that emits ultraviolet light, and an ultraviolet light of the light-emitting element.
Excited by the emission wavelength and emits fluorescence longer than the emission wavelength
A light-emitting device comprising: a light-emitting fluorescent material, wherein the light-emitting element is an n-type nitride-based compound semiconductor layer;
Double heterostructure between the nitride-based compound semiconductor layer
In δGa containing n-type impurities_1-Has δN active layer
And the impurity concentration is 5 × 10¹⁷/ Cm^ThreeAs described above, the InδGa_1-δ value of δN layer is greater than 0 and 0.1 or less
Below, the InδGa_1-The thickness of the δN layer is 100 Å
And the composition formula of the fluorescent substance is gMgO.hMgF._Two・ GeO_Two: IMn, jCaO · kM1O · TiO_Two: LPr, mM2_TwoO_Three・ (P_1-nV_n)_TwoO_Five: OEu_TwoO_Three, M3_TwoO_TwoS: pEu, M4_TwoO: at least one selected from qEu
Light emitting device. However, 2.5 ≦ g ≦ 4.0, 0 ≦ h ≦ 1,
0.003 ≦ i ≦ 0.05,  M1 is at least selected from Zn, Mg, Sr and Ba.
Also one kind. j + k + 1 = 1, 0 <k ≦ 0.4, 0.000
01 ≦ l ≦ 0.2,  M2 is a small number selected from La, Y, Sc, Lu, and Gd.
At least one. 0.5 ≦ m ≦ 1.5, 0 <n ≦ 1, 0.0
01 ≦ o ≦ 0.5, M3 is a small number selected from La, Y, Ga, Sc, and Lu
At least one. 0.0005 ≦ p ≦ 0.1, M4 is at least one selected from La, Y, and Ga.
0.0005 ≦ q ≦ 0.1.