JP3604298B2 - Method of forming light emitting diode - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting diode in which an LED chip disposed in a package is sealed using a phosphor and a method of forming the same, and more particularly, to a light emitting direction of the light emitting diode, a change in a manufacturing process of a phosphor amount, and the like. The present invention relates to a method for forming a light-emitting diode, which is improved to reduce uneven color tone and uneven light emission.
[0002]
[Prior art]
Light emitting diodes (hereinafter, also referred to as LEDs) are small, efficient, and emit bright colors. In addition, since it is a semiconductor element, there is no risk of a broken ball. It has excellent initial drive characteristics and is resistant to vibration and ON / OFF lighting. Therefore, it is used as various indicators and various light sources. However, since LEDs have an excellent monochromatic peak wavelength, it is not possible to perform mixed color light emission such as white light in order to improve the efficiency. Therefore, the present applicant has developed a light emitting diode in which light emitted from the blue light emitting diode is color-converted by the phosphor using the blue light emitting diode and the phosphor. Light-emitting diodes using phosphors tend to cause uneven color and uneven brightness due to their characteristics.
[0003]
Specifically, it is a light-emitting diode that emits mixed light of light from a blue LED chip and light from a phosphor that absorbs the light and emits fluorescence of a longer wavelength. Even if there is too much light from the chip or too much light from the phosphor, the mixed color light may cause color unevenness. In particular, when a phosphor is arranged on an LED chip, if the path length of light of the blue LED chip that passes through the phosphor differs depending on the portion, partial color unevenness on the emission observation surface occurs.
[0004]
In order to eliminate such partial color unevenness and obtain a desired directional angle, the present applicant has developed a light emitting diode described in Japanese Patent Application Laid-Open No. 10-107325. As shown in FIG. 3, a recess is further formed on the bottom surface of the cup so as to reduce the difference in optical path length from the LED chip. By pouring the LED chip and the phosphor-containing resin that covers the LED chip into a recess that is narrower than the inside of the cup, the difference in path length of light emitted from the LED chip from the recess is reduced. As a result, the difference in the distance that the light emitted from the LED chip passes through the resin containing the phosphor is reduced, and substantially uniform light emission can be achieved.
[0005]
[Problems to be solved by the invention]
However, with the spread of fields of use of light-emitting diodes using phosphors, a plurality of light-emitting diodes are used at the same time, and more stringent conditions are imposed on color unevenness and luminance unevenness. I have. In particular, human tone perception is particularly sensitive in white. Therefore, even a slight difference in color tone is perceived as reddish white, greenish white, yellowish white, or the like. Further, such color unevenness is not only visible, but may not be used in a light emitting diode formed by selecting a color tone or the like according to a specific use such as a sensor. Therefore, the yield is greatly reduced. It is an object of the present applicant to provide a method for forming a light emitting diode capable of solving the above-described problem and forming a light emitting diode with less color tone unevenness and less uneven brightness with a high yield.
[0006]
[Means for Solving the Problems]
Accordingly, the present invention provides a sealing having a base having a concave portion on the surface, an LED chip disposed on the bottom of the base, and a phosphor on the LED chip for converting visible light from the LED chip into light of a longer wavelength. A method of forming a light emitting diode capable of emitting white light, which is a mixed color of visible light from an LED chip and fluorescent light from a phosphor, wherein the recess is at least two-step-shaped and the LED chip has There disposed light narrowing color unevenness emitted from the LED chip, and consists of the upper recess formed by including a rim portion to uniform the shape of suppressing the lower recess and the sealing member uneven light emission, the lower recess and the lower recess upper surface The present invention relates to a method for forming a light emitting diode capable of emitting white light by setting a pouring amount of a sealing member so that a sealing member containing a phosphor reaches a concave portion in an upper stage.
[0007]
As a result, it is possible to reduce uneven color tone and the like, which are caused by non-uniform pouring of the resin containing the phosphor.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
As a result of various experiments, the present inventor has found that by forming a specific amount of a mold member having a phosphor in a cup in which an LED chip is arranged, it is possible to improve color tone unevenness of a light emitting diode and obtain a light emitting diode with a high yield. The present invention has been accomplished.
[0009]
As shown in FIG. 2 (A), which is a partially enlarged view of a light emitting diode shown for comparison with the present invention, the distance that light emitted from an LED chip passes through a phosphor may differ in the optical path length due to fluorescent radiation. And the amount of light converted by the phosphor is different. In particular, when the light emitted from the LED chip is narrowed down to suppress color tone unevenness and light emission unevenness, when a recess is provided inside the cup and the LED chip and the resin containing the phosphor are formed in the recess, the manufacturing conditions change over time. The change in the amount of phosphor accompanying the influence significantly affects the path length of light emitted from the LED chip. Particularly, when the resin containing the phosphor is poured from the thin tube into the depression, the amount is as small as about 0.5 μl, and it is extremely difficult to form the resin with good mass productivity while adjusting the amount. Further, in order to flow the resin containing the phosphor through the thin tube, a resin having a relatively low viscosity of about 3000 CPS must be used. However, the viscosity of the phosphor-containing resin used first in equipment that is continuously mass-produced differs slightly from that of the phosphor-containing resin after a lapse of time during mass production. Therefore, even if a light emitting diode is formed similarly, the amount of the phosphor containing resin used for the light emitting diode formed first and the amount of the phosphor containing resin used for the light emitting diode formed later are different. It becomes. Such a difference in the amount of the phosphor-containing resin causes a remarkable difference in the distance that the light emitted from the LED chip passes through the resin because the recess is small. In this case, mass productivity is reduced if the amount of the phosphor is adjusted accurately, that is, there has been a trade-off between the reduction in color variation of the light emitting diode and the mass productivity. In particular, as described above, it was extremely difficult to give priority to the reduction in color variation.
[0010]
According to the present invention, as shown in the cross-sectional view of FIG. 2B, an edge portion extending outward, for example, is provided at an upper portion of the recess for mounting the LED chip inside the package, that is, at least a two-step recess is provided. In the light emitting diode, the amount of the resin is set so that the phosphor-containing resin reaches the widened portion, that is, the upper concave portion. As a result, even if the amount of the resin containing the phosphor fluctuates, the inside of the cup having a relatively large volume such as the upper concave portion is smaller than the inside of the recess having a relatively small volume as shown in FIG. There is little variation in thickness.
[0011]
Specifically, in FIGS. 2 (A) and 2 (B), it can be understood from the case where both the resin injection set values (1) and (4) have the same volume of resin in both cases. Cheap. First, when the amount of resin of the same volume has increased, the resin surface reached (2) in FIG. 2 (A) and reached only (5) in FIG. 2 (B). Next, when the amount of resin of the same volume is reduced, the resin surface is lowered to (3) in FIG. 2 (A), and is reduced only to (6) in FIG. 2 (B). As shown in FIG. 2, as shown in FIG. 2, although the resin having the same volume fluctuates, the vertical fluctuation of the resin surface position due to the fluctuation is smaller in FIG. 2B. That is, the variation in the resin thickness is small. As a result, a variation in the path length difference of the light emitted from the LED chip is small, and a light emitting diode having a desired color tone can be formed with a high yield.
[0012]
FIG. 1 shows a chip type LED as an example of a specific light emitting diode according to the present invention. The inside of the chip type LED housing has a lower recess in which an LED chip using a gallium nitride-based semiconductor is arranged and an edge portion for making the shape of the sealing resin uniform, that is, a package in which a two-stage recess is formed. ing. An LED chip is fixed in the lower recess using an epoxy resin or the like. A gold wire is used as the conductive wire, and each electrode of the LED chip is electrically connected to each electrode provided on the housing. _{(RE 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce LED chips those phosphors were mixed and dispersed in an epoxy resin cured form poured into the lower recess arranged. The phosphor-containing resin is set so as to flow in an amount larger than that of the lower recess. By supplying power to such a light emitting diode, the LED chip emits light. It is possible to form a light emitting diode capable of emitting white light or the like by mixing colors of light emitted from the LED chip and light emitted from the phosphor excited by the light emission with high mass productivity.
[0013]
Hereinafter, the method for forming the light emitting diode of the present invention will be described in more detail, but it goes without saying that the present invention is not limited to this.
A GaInN semiconductor having a main emission peak of 470 nm was used as a light emitting element. In the LED element, a TMG (trimethyl gallium) gas, a TMI (trimethyl indium) gas, a nitrogen gas and a dopant gas are caused to flow along with a carrier gas on a cleaned sapphire substrate, and a gallium nitride-based compound semiconductor is formed by MOCVD. Formed. By switching between SiH ₄ and Cp ₂ Mg as the dopant gas, a gallium nitride-based semiconductor having n-type conductivity and a gallium nitride-based semiconductor having p-type conductivity were formed to form a pn junction. (The p-type semiconductor is annealed at 400 ° C. or higher after film formation.)
After exposing each pn semiconductor surface by etching, each electrode was formed by a sputtering method. After a scribe line was drawn on the semiconductor wafer thus completed, the wafer was divided by an external force to form a 250 μm square LED element as a light emitting element.
[0014]
On the other hand, after a metal piece serving as a lead electrode was placed in a mold, a liquid crystal polymer was injected to form an insert, and after cooling, the package was formed by taking out the insert from the mold. The package was provided with an opening at the center, and a recess for accommodating the LED element and the mold sealing member was further provided at the bottom of the opening. That is, the concave portions are formed in two steps. The LED element was die-bonded with epoxy resin in the lower recess. Each electrode of the LED element and the external electrode were each wire-bonded with a gold wire to establish electrical continuity.
[0015]
The phosphor contained in the mold member was prepared by co-precipitating a solution obtained by dissolving rare earth elements of Y, Gd, and Ce in an stoichiometric ratio in an acid 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 was ball milled in water, washed, separated, dried, and finally formed through a sieve.
[0016]
80 parts by weight of the formed (Y _0.4 Gd _0.6 ) ₃ Al ₅ O ₁₂ : Ce phosphor and 100 parts by weight of the translucent epoxy resin were mixed well to form a sealing member. The sealing member was injected from the thin tube into a two-step recess in the package in which the LED elements were arranged. The injection amount is set so as to sufficiently fill the inside of the lowermost recess, and to fill the uppermost recess. The mold sealing member was cured at 150 ° C. for 5 hours after injection to form a light emitting diode as shown in FIG.
[0017]
Next, each component of the light emitting diode of the present invention will be described in detail with reference to FIG.
(Recesses 11, 15)
Among the at least two-step concave portions according to the present invention, the lower concave portion 11 is for accommodating the LED element 12, and the upper concave portion 15 makes the shape of the injected mold sealing member uniform and performs the sealing. The thickness of the resin due to the change in the injection amount of the member is reduced. Thus, the difference in the path length of the light from the LED element 12 is reduced, and the light from the LED element 12 and the light from the phosphor can be sufficiently mixed. That is, the difference in the path length of the light converted by the phosphor from the light of the LED element 12 can be substantially small or extremely small.
[0018]
The bonding between the LED element 12 and the lower recess 11 can be performed using a thermosetting resin or the like. Specifically, an epoxy resin, an acrylic resin, an imide resin, or the like is used. At the connection portion between the LED element and the concave portion 11, light, ultraviolet light, and the like emitted from the LED element are also reflected by the phosphor and the like, and the density becomes particularly high even in the concave portion 11. Therefore, it is conceivable that the luminous efficiency is reduced due to yellowing or the like due to deterioration of the resin at the connection portion. In order to prevent such deterioration of the connection portion, it is more preferable to use glass or a resin containing an ultraviolet absorber for the purpose of preventing the deterioration due to ultraviolet rays or reducing the ultraviolet absorption.
[0019]
Furthermore, in order to improve the light use efficiency of the light emitting diode, the surfaces of the lower concave portion 11 in which the LED elements are arranged and the upper concave portion 15 may be mirror-like, and the surfaces may have a reflection function. Specific examples of the material of the concave portion include those plated with silver or gold having high reflectivity, copper, copper with iron, copper with tin, aluminum alloy, and ceramics with metallized patterns.
[0020]
(Phosphor)
Next, the phosphor contained in the sealing member filled in the recesses 11 and 15 will be described. The phosphor used in the present invention refers to a phosphor that emits light when excited by at least visible light emitted from a semiconductor light emitting layer. The light emitted from the LED element 12 using the gallium nitride-based compound semiconductor and the light emitted from the phosphor are in a complementary color relationship, or the light from the LED element 12 and the light of the phosphor excited and emitted by the LED element 12 are respectively When the light corresponds to the three primary colors of light (red, green, and blue), white light emission can be displayed by mixing the light emission from the LED element and the light emission from the phosphor. Therefore, it is necessary that the light emitted from the LED element 12 and the light emitted from the phosphor pass through the mold sealing member outside the light emitting diode. By variously adjusting the ratio of the phosphor to the resin, the application and the filling amount, and by selecting the emission wavelength of the light emitting element, it is possible to provide an arbitrary color tone such as a light bulb color including white.
[0021]
Various types of phosphors excited by the semiconductor light emitting layer include inorganic phosphors, organic phosphors, fluorescent dyes, and fluorescent pigments. Specific phosphor, derivatives of perylene and _{(RE 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce (0 ≦ x <1,0 ≦ y ≦ 1, however, RE is at least one element selected from the group consisting of Y, Gd, and La). Particularly phosphor _{(RE 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: in the case of using the Ce is placed in contact with the LED element or close to, the irradiance (Ee) = 3 W · cm ⁻² or more and 10 W · cm ⁻² or less, a light emitting diode having sufficient light resistance can be obtained with high efficiency.
[0022]
_{(RE 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce phosphor, for garnet structure, heat, resistant to light and moisture, the peak of the excitation spectrum can be like in the vicinity of 470nm Can be. Further, the emission peak is around 530 nm, and a broad emission spectrum with a tail extending to 720 nm can be provided. Moreover, the emission wavelength shifts to a short wavelength by replacing part of the Al in the composition with Ga, and shifts to the long wavelength by replacing a part of the Y in the composition with Gd. By changing the composition in this way, the emission color can be continuously adjusted. Therefore, there is provided an ideal condition for converting the blue light emission of the nitride semiconductor to the white light emission such that the intensity on the long wavelength side can be continuously changed by the composition ratio of Gd.
[0023]
Further, a light-emitting diode having an LED element using a gallium nitride-based semiconductor and a phosphor containing a rare earth element samarium (Sm) in a yttrium aluminum garnet phosphor (YAG) activated with cerium Can further improve light efficiency.
Such a phosphor uses an oxide as a raw material of Y, Gd, Ce, Sm, Al, La and Ga, or a compound which easily becomes an oxide at a high temperature, and thoroughly mixes them in a stoichiometric ratio. To obtain the raw material. Alternatively, a co-precipitated oxide obtained by co-precipitating a solution obtained by dissolving rare earth elements of Y, Gd, Ce, and Sm in an acid at a stoichiometric ratio with oxalic acid, and calcining the same, aluminum oxide, gallium oxide To obtain a mixed raw material. 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 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.
[0024]
_{(Y 1-p-q-} r Gd p Ce q Sm r) 3 Al 5 O 12 phosphor, by containing Gd in the crystal, in particular to increase the excitation emission efficiency of 460nm or longer wavelength region Can be. Due to the increase in the content of gadolinium, the emission peak wavelength shifts from 530 nm to 570 nm to a longer wavelength, and the entire emission wavelength shifts to the longer wavelength side. When a reddish luminescent color is required, it can be achieved by increasing the substitution amount of Gd. On the other hand, as Gd increases, the emission luminance of blue light gradually decreases. Therefore, p is preferably 0.8 or less, and more preferably 0.7 or less. More preferably, it is 0.6 or less.
[0025]
Containing _{Sm (Y 1-p-q} -r Gd p Ce q Sm r) 3 Al 5 O 12 phosphor, lowering of the temperature characteristics is small regardless of the increase in the content of Gd. By including Sm in this manner, the emission luminance of the phosphor at a high temperature is greatly improved. The degree of the improvement increases as the content of Gd increases. That is, it was found that a composition in which Gd was increased and redness was given to the emission color tone of the phosphor was more effective in improving the temperature characteristics due to the inclusion of Sm. (Note that the temperature characteristic is represented by a relative value (%) of the emission luminance of the same phosphor at a high temperature (200 ° C.) with respect to the excitation emission luminance at room temperature (25 ° C.) of 450 nm blue light. Yes.)
When the content of Sm is in the range of 0.0003 ≦ r ≦ 0.08, the temperature characteristic is preferably 60% or more. When r is smaller than this range, the effect of improving the temperature characteristics is reduced. On the other hand, when r is larger than this range, the temperature characteristics are conversely deteriorated. In the range of 0.0007 ≦ r ≦ 0.02, the temperature characteristic is 80% or more, which is the most preferable.
[0026]
Ce has a relative emission luminance of 70% or more in the range of 0.003 ≦ q ≦ 0.2. When q is 0.003 or less, the luminance decreases due to a decrease in the number of excitation and emission centers by Ce, and conversely, when it exceeds 0.2, concentration quenching occurs. Specifically, (Y _0.39 Gd _0.57 Ce _0.03 Sm _0.01 ) ₃ Al ₅ O ₁₂ phosphor is exemplified.
In the light emitting diode of the present invention, the phosphor may be a mixture of two or more phosphors. That, Al, Ga, Y, the content of La and Gd and Sm are two or more different _{(RE 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: by mixing Ce phosphor RGB wavelength components can be increased. By using a color filter for this, it can also be used for a full-color liquid crystal display device.
[0027]
(LED element 12)
Examples of the LED element 12 used in the present invention include a nitride-based compound semiconductor capable of efficiently emitting relatively short wavelength light capable of efficiently exciting a phosphor. In the LED element which is a light emitting element, a semiconductor such as InGaN is formed as a light emitting layer on a substrate by MOCVD or the like. Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, and a pn junction, a heterostructure, and a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal thereof. Further, 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.
[0028]
When a gallium nitride-based compound semiconductor is used, a material such as sapphire, spinel, SiC, Si, or ZnO is used for the semiconductor substrate. In order to form gallium nitride having good crystallinity, a sapphire substrate is preferably used. A buffer layer such as GaN or AlN is formed on the sapphire substrate, and a gallium nitride semiconductor having a pn junction is formed thereon. Gallium nitride-based semiconductors exhibit n-type conductivity without being doped with impurities. When a desired n-type gallium nitride semiconductor is formed, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, or the like as an n-type dopant. On the other hand, when a p-type gallium nitride semiconductor is formed, p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped.
[0029]
Since gallium nitride-based compound semiconductors are difficult to become p-type only by doping with a p-type dopant, it is preferable to lower the resistance by introducing a p-type dopant, heating by a furnace, irradiating a low-speed electron beam, irradiating plasma, or the like. After the exposed surfaces of the p-type semiconductor and the n-type semiconductor are formed by etching or the like, each electrode having a desired shape is formed on the semiconductor layer by using a sputtering method, a vacuum evaporation method, or the like.
[0030]
Next, the formed semiconductor wafer or the like is directly full-cut by a dicing saw in which a blade having a diamond cutting edge is rotated, or a groove having a width larger than the cutting edge width is cut (half cut). Crack the wafer. 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, the LED element 12 which is a gallium nitride-based compound semiconductor can be formed.
[0031]
In the case of emitting white light in the light emitting diode of the present invention, the main emission wavelength of the light emitting element is preferably 400 nm or more and 530 nm or less, more preferably 420 nm or more and 490 nm or less in consideration of the complementary color with the phosphor. In order to further improve the efficiency of the LED element and the efficiency of the phosphor, the thickness is more preferably 450 nm or more and 475 nm or less.
[0032]
(Conductive wire 13)
The conductive wire 13 is required to have good ohmic properties, mechanical connectivity, electrical conductivity, and thermal conductivity with the electrodes of the LED element 12. The thermal conductivity is preferably at least 0.01 cal / cm ² / cm / ° C., more preferably at least 0.5 cal / cm ² / cm / ° C. The diameter of the conductive wire is preferably Φ10 μm or more and Φ45 μm or less in consideration of workability and the like. Specific examples of such conductive wires include conductive wires using metals such as gold, copper, platinum, and aluminum and alloys thereof.
[0033]
(Mold sealing member)
The mold members filled in the recesses 11 and 15 are for protecting the LED element 12, the conductive wire 13, and the like from the outside according to the usage of the light emitting diode. The mold member can be formed using various resins, glass, or the like. In addition, the filling amount is set in advance to an amount exceeding at least the upper surface of the lower concave portion in the package in order to obtain a light emitting diode with less color tone unevenness and uneven brightness.
[0034]
As a specific material for the mold member, a transparent resin having excellent weather resistance, such as an epoxy resin, a urea resin, or silicone, or glass is preferably used. Further, by including a diffusing agent in the mold member, the directivity from the LED element can be reduced and the viewing angle can be increased. As a specific material of the diffusing agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide, or the like is suitably used.
[0035]
(Lead electrode 14)
As the lead electrode, an LED element disposed in the recess is electrically connected to the outside of the package, and therefore, a lead electrode having excellent electric conductivity is preferable. Specific examples of the material include metallized metal such as nickel or an electric conductor such as phosphor bronze. Also, the surface of such a material may be plated with silver or gold or the like, and the surface may be used as a light reflecting member so as to efficiently emit light from the LED element to the outside as well as the electrode member. it can.
[0036]
Hereinafter, in order to confirm the effect of the light emitting diode according to the present invention, a light emitting diode as shown in FIG. 3 was formed, and a comparative experiment with the light emitting diode according to the present invention was performed.
The light emitting diode of FIG. 3 was formed in the same manner as that of the present invention except that the set value of the amount of the resin containing the phosphor was set on the lowermost surface of the two-step concave portion. Variations in light color were observed between the 1200 light emitting diodes thus formed and the 1200 light emitting diodes according to the present invention. The variation of each light emitting diode formed in the method of the present invention within an allowable range was less than about 21% of each light emitting diode of FIG.
[0037]
Of the 1200 light-emitting diodes in FIG. 3, the one in which light color variation was conspicuous was examined, and it was found that the phosphor-containing resin was lower than the surface of the lower recess 31 in the two-stage recess. This is because the set value of the resin injection amount could not be controlled because 1200 pieces were mass-produced. When the amount of resin is larger than the set value, the light emitting diode of FIG. 3 also exhibits the same effect as that of the present invention. In this case, the effect of providing the two-step concave portions 31 and 35 is lost.
[0038]
On the other hand, as in the light emitting diode of the present invention, if at least a two-step concave portion is provided and the set value of the injected resin amount is set in advance to an amount exceeding the lower concave portion, the injected resin amount varies somewhat. Even if the amount of the resin is reduced, it is possible to prevent the resin from being lower than the surface of the lower concave portion as much as possible, so that the problem seen in the light emitting diode of FIG.
[0039]
【The invention's effect】
The light-emitting diode of the present invention is provided with at least a two-step recess and the amount of the resin containing the phosphor is set to an amount exceeding the upper surface of the lower recess, so that the injection amount of the sealing member containing the phosphor is increased. Even if the amount of light is slightly increased or decreased, it is possible to form a light emitting diode with extremely small color shift, uneven color, and uneven brightness with good mass productivity.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a chip type LED which is an example of a light emitting diode of the present invention.
FIG. 2 is a schematic view for explaining an effect of the present invention, and FIG. 2A is a partially enlarged view of a light emitting diode shown for comparison. FIG. 2B is a partially enlarged view of a light emitting diode of the present invention having a two-step concave portion.
FIG. 3 is a schematic sectional view of a light emitting diode shown for comparison with the present invention.
[Explanation of symbols]
11, 31 ... of the stepped recesses, lower stepped recesses 12, 32 ... LED elements 13, 33 ... conductive wires 14, 34 ... lead electrodes 15, 35 ... of the stepped recesses , Upper recess

Claims (1)

A base having a concave portion on the surface, an LED chip disposed on the bottom of the base, and a sealing member containing a phosphor that converts visible light from the LED chip into light of a longer wavelength on the LED chip. A method for forming a light emitting diode capable of emitting white light that is a mixed color of visible light from the LED chip and fluorescent light from a phosphor,
The recess is at least two-stepped, in which an LED chip is arranged, a light emitted from the LED chip is narrowed down, and a lower-stage recess that suppresses uneven color tone and uneven light emission and an edge portion that makes the shape of the sealing member uniform are provided. A white system comprising an upper concave portion, and setting the pouring amount of the sealing member so that the sealing member containing the phosphor reaches the upper concave portion beyond the upper surface of the lower concave portion and the lower concave portion. A method for forming a light-emitting diode capable of emitting light.

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