KR101599135B1 - Led encapsulant comprisng a rare earth metal oxide particles - Google Patents

Abstract

The present invention relates to an LED encapsulant comprising rare earth metal oxide particles, and more particularly, to an LED encapsulant containing a compound represented by the following formula (1) in a polymer resin in an amount of 50% by weight or less based on the total composition. The rod material composition of the present invention has the effect of dramatically improving the light extraction efficiency of light generated in the LED chip.
[Chemical Formula 1]
M _a (OH) _b (CO ₃ ) _c O _d
Wherein M is at least one element selected from Sc, Y, La, Al, Lu, Ga, Zn, V, Zr, Ca, Sr, Ba, Sn,
a is 1 or 2, b is 0 to 2, c is 0 to 3, and d is 0 to 3.
B, c and d are not simultaneously 0, and b and c are both 0 or 0 at the same time.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an LED encapsulant containing rare earth metal oxide particles,

The present invention relates to an LED encapsulant comprising rare earth metal oxide particles.

 2. Description of the Related Art A light emitting diode (LED), which is a type of semiconductor used to transmit and receive a signal by converting electricity into infrared rays or light by using characteristics of a compound semiconductor, is a high efficiency, (LED) has been widely used for backlighting and illumination of display devices because it has advantages of long life, miniaturization, light weight and low power consumption. .

Typically, the LED package consists of an LED chip, an adhesive, an encapsulant, a phosphor, and a heat dissipation component. Among them, the LED encapsulant surrounds the LED chip and protects the LED chip from external impact and environment.

However, since LED light must pass through the LED encapsulant in order to emerge from the LED package, the LED encapsulant must have a high optical transparency, that is, a high light transmittance, and a high refractive index Is required.

Epoxy resins with high refractive index and low cost have been widely used as LED encapsulants. However, since epoxy resins have low heat resistance, they have a problem that they are deteriorated by heat in high power LEDs. In the case of white light LEDs, Resulting in a problem of lowering the luminance.

As an alternative to this, a silicone resin having excellent light resistance in a low wavelength region is used (the bonding energy of the siloxane bond (Si-O-Si) of the silicone resin is 106 kcal / mol, 20 kcal / mol or more, which is superior in heat resistance and light resistance), and the silicone resin has a problem that the light extraction efficiency is lowered and the adhesiveness is weak due to a low refractive index.

Conventional techniques for sealing materials can be understood with reference to the following Patent Documents 1 and 2. [ As a result, the entire contents of the following Patent Documents 1 and 2 are incorporated in this specification as a prior art.

Patent Document 1 discloses a polyimide film comprising a polysiloxane prepolymer having a TiO ₂ domain having an average domain size of less than 5 nm and comprising 20 to 60 mol% of TiO ₂ (Total solids basis), having a refractive index of > 1.61 to 1.7, and a liquid at room temperature and atmospheric pressure, for curing the liquid polysiloxane / TiO ₂ composite for use as a light emitting diode encapsulant.

Patent Document 2 discloses a composition for an encapsulant of an optoelectronic device, which comprises an epoxy resin and a polysilazane which is cured with the epoxy resin, a sealing material formed from the composition, and a sealing material .

KR Published 10-2012-0129788 A (November 28, 2012) KR public 10-2012-0117548 A (October 24, 2012)

There are two methods for increasing the light efficiency of the LED,

The first is a method of increasing the total amount of light generated in the chip,

The second method is to increase the light extraction efficiency by extracting the generated light amount as much as possible out of the LED.

However, as described above, usually, in the LED package, the encapsulation material encapsulates the LED chip, and only about 15% of the chip-generated light energy is outputted as light and the remainder is absorbed in the encapsulant or the like.

Accordingly, a part where attention is focused on the light efficiency of the LED is to improve the light extraction efficiency so that light generated in the light emitting layer of the LED is effectively lost to the outside without being lost by total internal reflection of the LED chip.

Currently, several technologies are being studied to increase the light extraction efficiency so as to extract the light amount as much as possible out of the LED. However, there is still a need for improvement.

Accordingly, it is an object of the present invention to provide an encapsulant composition that dramatically improves the light extraction efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the conventional art,

The present invention provides an LED encapsulant comprising a compound represented by the following formula (1) in a polymer resin in an amount of 50% by weight or less based on the total composition.

[Chemical Formula 1]

M _a (OH) _b (CO ₃ ) _c O _d

Wherein M is at least one element selected from Sc, Y, La, Al, Lu, Ga, Zn, V, Zr, Ca, Sr, Ba, Sn,

a is 1 or 2, b is 0 to 2, c is 0 to 3, and d is 0 to 3.

B, c and d are not simultaneously 0, and b and c are both 0 or 0 at the same time.

In the present invention, the compound of Formula 1 is Y (OH) CO _3, and the compound of Formula 1 is contained in an amount of 1 to 20 wt% relative to the total composition.

Also, the present invention provides the LED encapsulant, wherein the compound of formula (1) is Y ₂ O _3, and the content of the compound is 20 wt% or less with respect to the total composition.

Also, the present invention provides the LED encapsulant having a refractive index within the range of 1.6 to 2.3.

In the present invention, the polymer resin is at least one selected from a silicone resin, a phenol resin, an acrylic resin, a polystyrene, a polyurethane, a benzoguanamine resin, and an epoxy resin. Provide ashes.

In the present invention, there is also provided an LED encapsulant characterized by further comprising phosphor particles.

The rod material composition of the present invention has the effect of dramatically improving the light extraction efficiency of light generated in the LED chip.

1 is an SEM photograph showing rare earth oxide particles (Y (OH) CO ₃ particles) of the present invention.
2 is an SEM photograph showing rare earth oxide particles (Y ₂ O ₃ particles) of the present invention.
FIGS. 3 to 8 show calibration curves showing changes in luminance depending on the contents of Y (OH) CO ₃ particles and Y ₂ O ₃ particles, respectively.

Hereinafter, the present invention will be described in detail.

The present invention relates to a resin for encapsulating an LED package and a rare earth metal oxide additive having improved light extraction efficiency. More particularly, the present invention relates to a resin for encapsulating light in an LED package, And the rare earth metal oxide nanoparticles exhibiting high luminous efficiency by extracting the rare earth metal oxide nanoparticles.

To this end,

The polymer resin contains 50% by weight or less of a compound represented by the following formula (1), based on the total composition.

[Chemical Formula 1]

M _a (OH) _b (CO ₃ ) _c O _d

Wherein M is at least one element selected from Sc, Y, La, Al, Lu, Ga, Zn, V, Zr, Ca, Sr, Ba, Sn,

a is 1 or 2, b is 0 to 2, c is 0 to 3, and d is 0 to 3.

B, c and d are not simultaneously 0, and b and c are both 0 or 0 at the same time.

When the compound of Formula 1 is contained in the polymer resin, the content is preferably within 50 wt%, more preferably within 30 wt% of the total composition in terms of light extraction efficiency. If too small amounts are included, it may be insufficient to improve the light extraction efficiency, and conversely, if too much is included, the light extraction efficiency may be rather lowered. That is, although there is a slight difference depending on the wavelength of light or the kind of compound, there is an optimum range of content for maximizing the light extraction efficiency. If the content exceeds 50% by weight regardless of the wavelength of light or the kind of compound, This is because the extraction efficiency is not good. A more detailed description thereof will be understood with reference to the following Examples and Experimental Examples.

The compound of Formula 1 may be at least one compound selected from Y (OH) CO ₃ and Y ₂ O _{3. In} particular, the Y (OH) CO ₃ may be used in an amount of 1 to 20 wt% And Y ₂ O ₃ is preferably contained in an amount of 20% by weight or less based on the total composition. If the content is out of the above range and the content is small or large, it is difficult to optimize the luminance. A more detailed description thereof will be understood by the following Examples and Experimental Examples.

The compound of Formula 1 preferably has a refractive index within a range of 1.6 to 2.3. If it is less than 1.6 and exceeds 2.3, the light extraction efficiency may not be increased. This is because the refractive index of the conventional silicon encapsulant is about 1.5 and the refractive index of the GaN chip is about 2.4.

The total reflection problem in the light emitting device package chip is caused by the total reflection at the boundary between the device and the outside air and the silicon as the external sealing material. According to Snell's law, the critical angle ( θcrit ) that light or waves can pass through between two isotropic media with different refractive indices is as follows.

Critical angle, which due to the air (n _air = 1), silicon (n _silicon = 1.5) than that of the GaN refractive index of smoking a large difference as about 2.5 is the light produced in the light emitting device package can escape to the outside are each θ _{GaN / air} = 23 [deg.] and [theta] _{GaN / Silicon} = 37 [deg.]. As a result, the light extraction efficiency is only about 15%.

The polymer resin may be a polymer resin widely used in the related art and is not particularly limited. For example, at least one selected from a silicone resin, a phenol resin, an acrylic resin, a polystyrene, a polyurethane, a benzoguanamine resin, and an epoxy resin may be used. The silicone resin may be polysilane, poly Siloxane, and combinations thereof. The phenolic resin may be at least one phenol resin selected from a bisphenol-type phenol resin, a resol-type phenol resin, and a resol-type naphthol resin. The epoxy- The resin may be at least one epoxy resin selected from bisphenol F type epoxy, bisphenol A type epoxy, phenol novolak type epoxy, and cresol novolak type epoxy.

The encapsulant composition of the present invention may further include phosphor particles to be used for the purpose of realizing a desired color.

Hereinafter, the present invention will be described in more detail by way of examples. It is to be understood that the following embodiments are for the purpose of illustration only and are not intended to limit the scope of the present invention.

Example

Example  One

Preparation of Y (OH) CO ₃ particles is based on 100 mL of distilled water. 4 g of yttrium nitrate hydrate and 40 g of urea were dissolved in 100 ml of distilled water, and the mixture was thoroughly stirred for 30 minutes. After stirring, the pH was adjusted to 5-6 via a base of nitric acid and ammonium hydroxide. The mixed solution was heated at 90 DEG C and stirred for 1 hour, followed by filtration and washing with distilled water three times. The washed Y (OH) CO ₃ particles were dried in an oven at 70 ° C for 3 hours to prepare particles having a size of 300 nm or less.

FIG. 1 shows SEM photographs of the particles produced.

After adding the Y (OH) CO ₃ particles (99% by weight of a silicone resin and 1% by weight of Y (OH) CO ₃ ) to a silicone resin (OE 6631 A and OE 6631 B mixed in a ratio of 1: 2) , And the mixture was homogenized by homogenizer to prepare an encapsulant composition.

Example  2

A silicone-based resin, the Y (OH) CO ₃ particles, silicone-based resin of 98% by weight, Y (OH) CO ₃ 2, except that the addition to the weight% ratio, all the same manner as in Example 1 encapsulant composition and .

Example  3

A silicone-based resin, the Y (OH) CO ₃ particle, a silicone resin, 97% by weight, Y (OH) CO _{3 3,} except that the addition to the weight% ratio, for both the first embodiment the same encapsulant composition and .

Example  4

Except that the silicone resin was added with the Y (OH) CO ₃ particles in a proportion of 93% by weight of the silicone resin and 7% by weight of Y (OH) CO _{3 in the} silicone resin, .

Example  5

A silicone-based resin, the Y (OH) CO ₃ particles, 90% by weight of a silicone-based resin, Y (OH) CO ₃ 10, except that the addition to the weight% ratio, for both the first embodiment the same encapsulant composition and .

Example  6

Y ₂ O ₃ particles were produced by firing after preparation of Y (OH) CO ₃ . First, Y (OH) CO ₃ is based on 100 mL of distilled water. 4 g of yttrium nitrate hydrate and 40 g of urea were dissolved in 100 ml of distilled water, and the mixture was thoroughly stirred for 30 minutes. After stirring, the pH was adjusted to 5-6 via a base of nitric acid and ammonium hydroxide. The mixed solution was heated at 90 DEG C and stirred for 1 hour, followed by filtration and washing with distilled water three times. The washed Y (OH) CO ₃ particles were dried in a 70 ° C oven for 3 hours. The dried Y (OH) CO ₃ particles were calcined at 900 ° C for 3 hours in an oxidizing atmosphere to obtain Y ₂ O ₃ particles of 300 nm or less in size.

FIG. 2 shows SEM photographs of the produced particles.

Y ₂ O ₃ particles (silicon-based resin 99 wt%, Y ₂ O ₃ 1 wt%) were added to a silicone resin (OE 6631 A and OE 6631 B mixed at a ratio of 1: 2) And homogenized to prepare a sealant composition.

Example  7

An encapsulant composition was prepared in the same manner as in Example 6, except that the Y ₂ O ₃ particles were added to the silicone resin in a ratio of 98% by weight of the silicone resin and ₂ % by weight of Y ₂ O ₃ .

Example  8

An encapsulant composition was prepared in the same manner as in Example 6 except that the Y ₂ O ₃ particles were added to the silicone resin in a ratio of 97% by weight of the silicone resin and 3% by weight of Y ₂ O ₃ .

Example  9

An encapsulant composition was prepared in the same manner as in Example 6, except that the Y ₂ O ₃ particles were added to the silicone resin at a ratio of 93% by weight of the silicone resin and 7% by weight of Y ₂ O ₃ .

Example  10

A sealant composition was prepared in the same manner as in Example 6, except that the Y ₂ O ₃ particles were added to the silicone resin at a ratio of 90% by weight of the silicone resin and 10% by weight of Y ₂ O ₃ .

Example  11

A silicone-based resin, the Y (OH) CO ₃ particles, silicone-based resin 87% by weight, Y (OH) CO ₃ 13, except that the addition to the weight% ratio, for both the first embodiment the same encapsulant composition and .

Example  12

An encapsulant composition was prepared in the same manner as in Example 6, except that the Y ₂ O ₃ particles were added to the silicone resin at a ratio of 87% by weight of the silicone resin and 13% by weight of Y ₂ O ₃ .

Comparative Example

The silicone resin OE 6631 A and OE 6631 B were mixed in a 1: 2 ratio to prepare a 100 wt% encapsulant composition.

Experimental Example

Experimental Example  One

The encapsulant compositions of Examples 1 to 10 and Comparative Examples were mounted in an LED package having a blue LED (wavelength: 450 nm) chip, and the luminance increase rate was measured. The light emitting device package used is a chip which is connected to the lead frame by die bonding. A metal wire bonding is performed so that the light emitting element and the lead frame are electrically connected to each other, and then the sealing resin is molded with an encapsulant in which the transparent resin encapsulating material and the inorganic nanoparticles are dispersed. The luminance increase rate is a percentage of the increase in luminance based on Comparative Example 100. The luminance was measured by a DARSA Pro 5200 PL System machine manufactured by Professional Scientific Instrument, Korea.

The results are shown in Table 1 below.

Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Brightness increase rate (%) 100 99.7 102.9 105.9 110.1 109.6 107.6 107.1 102.6 87.6 77.1

Experimental Example  2

The encapsulant compositions of Examples 1 to 12 and Comparative Examples were mounted in an LED package having a green LED (wavelength 520 nm) chip, and the luminance increase rate was measured. The light emitting device package used is a chip which is connected to the lead frame by die bonding. A metal wire bonding is performed so that the light emitting element and the lead frame are electrically connected to each other, and then the sealing resin is molded with an encapsulant in which the transparent resin encapsulating material and the inorganic nanoparticles are dispersed. The luminance increase rate is a percentage of the increase in luminance based on Comparative Example 100. The luminance was measured by a DARSA Pro 5200 PL System machine manufactured by Professional Scientific Instrument, Korea.

The results are shown in Table 2 below.

Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example
11 Also increase% 100 102.3 102.6 104.7 108.6 113.2 104.7 103.5 104.1 100.4 94.6 105.3

Experimental Example  3

The encapsulant compositions of Examples 1 to 12 and Comparative Examples were mounted in an LED package having a red LED (wavelength: 620 nm) chip, and the luminance increase rate was measured. The light emitting device package used is a chip which is connected to the lead frame by die bonding. A metal wire bonding is performed so that the light emitting element and the lead frame are electrically connected to each other, and then the sealing resin is molded with an encapsulant in which the transparent resin encapsulating material and the inorganic nanoparticles are dispersed. The luminance increase rate is a percentage of the increase in luminance based on Comparative Example 100. The luminance was measured by a DARSA Pro 5200 PL System machine manufactured by Professional Scientific Instrument, Korea.

The results are shown in Table 3 below.

Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example
11 Also increase% 100 100.7 100.9 102.8 106.3 108.4 101.6 104.6 103.6 102.7 98.5 109.2

As can be seen from Tables 1 to 3, when the sealing material composition contains the rare earth metal inorganic oxide particles, the brightness was remarkably increased. However, Y ₂ O ₃ particles, Y (OH) compared to the CO ₃ particles, low content has been shown high luminance increase rate, and contents in a rather showed a low luminance increase rate, the brightness increase peak also Y (OH) CO ₃ particles Respectively.

FIGS. 3 to 8 show calibration curves showing changes in luminance depending on the contents of Y (OH) CO ₃ particles and Y ₂ O ₃ particles, respectively. From this curve, it was confirmed that the content range of the maximum value of the luminance increase was confirmed, and it was confirmed that the content that can give the optimum luminous efficiency differs according to the particle type and the emission wavelength.

Claims (6)

An LED encapsulant comprising the polymeric resin represented by the following formula (1) in an amount of 50% by weight or less based on the total composition.
[Chemical Formula 1]
M _a (OH) _b (CO ₃ ) _c O _d
Wherein M is at least one element selected from Sc, Y, La, Al, Lu, Ga, Zn, V, Zr, Ca, Sr, Ba, Sn,
a is 1 or 2, b is 0 to 2, c is 0 to 3, and d is 0 to 3.
However, b and c are not 0 at the same time. [2] The LED encapsulant according to claim 1, wherein the compound of Formula 1 is Y (OH) CO ₃ , and the composition contains 1 to 20 wt% of the composition. delete The LED encapsulant according to claim 1, wherein the compound of Formula 1 has a refractive index within a range of 1.6 to 2.3. The LED package according to claim 1, wherein the polymer resin is at least one selected from a silicone resin, a phenol resin, an acrylic resin, a polystyrene, a polyurethane, a benzoguanamine resin, and an epoxy resin . The LED encapsulating material according to claim 1, further comprising phosphor particles.

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