KR20100102906A - Diffusive illuminating cover for led and led lamp comprising the same - Google Patents

Abstract

PURPOSE: A light-transmissive type diffusive unit for a light emitting diode(LED) and an LED illuminating lamp including the same are provided to save a manufacturing cost by reducing the usage of a light diffusing agent. CONSTITUTION: A light-transmissive type diffusive unit for an LED is composed of a crystalline polypropylene resin. A pattern with the 90% or more transferring rate is formed on the light-transmissive type diffusive unit for the LED. The polypropylene resin is the homopolymer of propylene monomer or the copolymer of one or more monomers selected from a group including ethylene, 1-butene, 1-pentene, 1-hexene, and 1-octene.

Description

Light transmitting diffuser for LED and LED lighting lamp equipped with it {DIFFUSIVE ILLUMINATING COVER FOR LED AND LED LAMP COMPRISING THE SAME}

The present invention relates to a light-transmitting diffusing member for an LED capable of providing an excellent surface light source image and an LED lamp having the same.

Recently, as a light source of various lighting apparatuses, light emitting diodes (LEDs), which emit light using a light emitting phenomenon generated when voltage is applied to a semiconductor, have attracted attention.

These LEDs are smaller than conventional light sources, have a long lifespan, and have an advantage of high energy efficiency and low operating voltage since electrical energy is directly converted into light energy. It is used in various fields, such as a device and a headlight for automobiles.

Generally, as shown in FIG. 1, the LED illuminator 100 includes a LED module 120 having a plurality of LED elements 121 mounted on a substrate 122, and a light-transmitting diffuser in which the LED module 120 is embedded. The member 110 is provided. In addition, the cap 130 is additionally installed at both ends of the lamp 100 to seal both ends of the lamp 100 and to apply power.

The light-transmissive diffusing member diffuses the light emitted from the LED element, and has good transparency and good physical properties such as impact resistance, heat resistance, and weather resistance. Members made of polycarbonate resins applicable to various fields are mainly used. In addition, amorphous resins such as styrene resins and acrylic resins are mainly used.

On the other hand, since the light emitted from the LED device has a strong straightness, a hot spot occurs, and thus a point light source remains in the output window, thereby degrading an image. In order to improve this, a method of adding a light diffusing agent in the manufacture of the light transmitting diffusion member or forming a repetitive pattern in extrusion molding has been proposed. However, since the surface of the light transmitting diffuser used in fluorescent lamps is not a flat surface but a curved shape, it is difficult to narrowly adjust the pitch between each pattern and the pattern, and thus it is difficult to obtain a desired effect. In addition, the light transmissive member made of the amorphous resin as described above has a low transfer rate of the pattern during extrusion molding, and thus it is difficult to sufficiently exhibit an image improvement effect.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light transmitting diffuser member for LED, which can be improved to an image of a surface light source instead of a point light source when applied to an LED lighting lamp with a high pattern transfer rate without significantly reducing or using the light diffusing agent. It is done.

In addition, another object of the present invention is to provide an LED lamp provided with the light-transmissive diffusion member.

In order to achieve the above object, the present invention provides a light-transmitting diffuser for LED formed with a pattern consisting of a crystalline polypropylene resin 90% or more transfer rate.

In addition, the present invention provides an LED lamp provided with the light-transmissive diffusion member.

Translucent diffuser for LED of the present invention has a high transfer rate for the pattern engraved in the mold when extrusion or injection molding is 90% or more and can reduce the pitch between the pattern, the light-transmitting diffuser such as LED lamps, in particular fluorescent lamps When applied, it can provide excellent image of surface light source instead of point light source. In addition, since the amount of the light diffusing agent that has been used for improving the conventional image can be greatly reduced, manufacturing cost is reduced and economical.

The present invention relates to a light-transmitting diffusing member for an LED capable of providing an excellent surface light source image and an LED lamp having the same.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Translucent diffusion member for LED of the present invention is characterized in that the pattern consisting of a crystalline polypropylene resin is formed a transfer rate of 90% or more.

The polypropylene resin is preferably a crystalline resin, and may be a homopolymer (homopolymer) of the crystalline propylene monomer, or a block or random copolymer of the crystalline propylene monomer and an α-olefin monomer having 3 to 15 carbon atoms. .

Examples of the α-olefin monomer having 3 to 15 carbon atoms include ethylene, 1-butene, 1-pentene, 1-hexene and 1-octene, and these may be used alone or in combination of two or more thereof.

The α-olefin monomer may be included up to 30% by weight relative to 100% by weight of the copolymer. If the content exceeds 30% by weight, it is difficult to secure desired crystallinity and physical properties, so that the effect of improving the transfer rate may be insignificant.

The polypropylene resin is preferably a linear expansion coefficient of 100 to 200ppm / ℃ analyzed by the Thermal Mechanical Analysis (TMA) method in terms of the effect of improving the transfer rate of the pattern, more preferably 120 to 170ppm / It is ℃. If the coefficient of linear expansion is less than 100 ppm / ℃, the transfer rate of the pattern engraved in the mold may decrease during extrusion or injection molding, and if it exceeds 200 ppm / ℃, expansion or contraction occurs due to temperature change. There is a problem that is deformed.

The polypropylene resin is preferably syndiotactic or isotactic in terms of mechanical and thermal stability.

The polypropylene resin preferably has a melt flow index (230 ° C., 2160 g) of 0.5 to 20 g / min, more preferably 0.5 to 5 g / min. If the melt flow index does not fall within the above range, the fluidity and viscosity are too low or high, resulting in poor workability and lowering the transfer rate.

The polypropylene resin may be in powder form or pellet form, the shape of which is not particularly limited.

It is preferable that the translucent diffusion member for LEDs contains a nucleating agent with a polypropylene resin. The nucleating agent is a component that helps to control the crystalline temperature of the polypropylene resin, and significantly improves mechanical properties and transparency, such as rigidity.

As the nucleating agent, an inorganic nucleating agent such as talc and an organic nucleating agent may be used. Specific examples of the organic nucleating agent include carboxylic acid metal salts such as sodium benzoate, aluminum dibenzoate, potassium benzoate, lithium benzoate and sodium β-naphthalene sodium cyclohexanecarboxylate; Sorbitols such as benzylidene sorbitol and derivatives thereof; Phosphoric acid ester metal salts, such as phosphoric acid and 2, 2- methylbis (4, 6- di- t-butylphenyl) sodium, etc. are mentioned. In addition, poly-3-methylbutene-1, polyvinylcycloalkane, polyvinyltrialkylsilane, ethylene-propylene rubber (EPR), kebra fibers, and the like can be given, and these can be used alone or in combination of two or more thereof.

The nucleating agent is preferably included in 0.005 to 3 parts by weight based on 100 parts by weight of polypropylene resin.

In addition to the polypropylene resin, the light transmitting diffuser may further include a light stabilizer and an ultraviolet absorber.

A light stabilizer is a compound which can prevent the fall of a total light transmittance and can provide a light stabilizer effect, The kind in particular is not restrict | limited. Specific examples include piperidinyl esters (piperidinyl esters), oxazolidines, piperidinooxazolidines, piperidinespiroacetals, and diazacycloalkanones (diazacycloalkanones) compounds. These etc. can be mentioned, These can be used individually or in combination of 2 or more types.

The light stabilizer may be included in 0.01 to 5 parts by weight based on 100 parts by weight of polypropylene resin, preferably 0.10 to 2 parts by weight. If the content is in the above range, the desired light stability effect can be obtained without deteriorating the total light transmittance and physical properties, and the cost can be reduced.

The type of UV absorber is not particularly limited as long as the compound blocks a wavelength of 400 nm or less. Specifically 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2, Benzophenone compounds such as 2'-dihydroxy-4-methoxybenzophenone; 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- ( 3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (3-t-butyl -5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3 Benzotriazole-based compounds such as, 5-di-t-amyl-2-hydroxyphenyl) benzotriazole and 2- (2'hydroxy-5'-t-octylphenyl) benzotriazole; Malonic ester compounds such as dimethyl malonate, diethyl malonate, dibenzyl malonate and diallyl malonate; N- (4-ethoxycarbonylphenyl) -N-methyl-N-phenylformamidine, N, N-bis (4-ethoxycarbonylphenyl) -N-benzylformamidine, N-3,5 -Di-t-butyl-4-hydroxybenzyl-N'-4-specific carbonylphenyl-N-phenylformamidine, N, N-bis (4-ethoxycarbonylphenyl-N-3,5 -Di-t-butyl-4-hydroxybenzylformamidine, N-4-butoxycarbonylphenyl-N'-4-ethoxycarbonylphenyl-N-3,5-di-t-butyl-4 -Formamidine type compounds, such as -hydroxybenzylformamidine, etc. are mentioned, These can be used individually or in combination of 2 or more types.

The ultraviolet absorbent may be included in an amount of 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the polypropylene resin.

In addition, the light transmitting diffusion member of the present invention may further include a small amount of a light diffusing agent, the content may be 0.01 to 2 parts by weight, preferably 0.01 to 0.50 parts by weight based on 100 parts by weight of the polypropylene resin.

The type of light diffusing agent is not particularly limited, and may be used alone or in combination of two or more kinds of organic particles, inorganic particles or organic-inorganic composite particles. Specifically, organic particles such as silicone-based, acrylic-based, styrene-based, methyl methacrylate-styrene copolymer, polycarbonate-based, and olefin-based; Inorganic particles such as silica, talc, calcium carbonate, barium sulfate and titanium dioxide; And organic-inorganic composite particles having a core-shell structure in which surfaces of inorganic particles are modified.

In addition to the above components, the light transmissive diffusion member may further include additives such as a fluorescent brightener, an antioxidant, a heat stabilizer, an antistatic agent, and the like.

The translucent diffusion member of the present invention may be prepared by mixing such components using a Henschel mixer or Brabender, and then extruding or injection molding such as a double extrusion method. In particular, in the case of a three-dimensional shape, it is preferable to manufacture by injection molding.

The translucent diffusion member of the present invention is characterized in that a pattern is formed and the transfer rate of the pattern is excellent.

Examples of the pattern formed on the light transmitting diffusing member include those shown in FIG. 2. A planar pattern in which patterns having the same height (h) and shape are repeated as shown in (a) and (b) of FIG. 2, a planar pattern of a more complicated structure in which patterns having different heights are repeated as in (c), Or a gradation pattern having different heights and arranged in various directions as shown in (d).

The pattern may be formed over the surface of the light transmitting diffusion member, and may be formed only in part. In this case, the pattern may be formed in any of an outer direction and an inner direction of the light transmitting diffusion member.

In addition, the same pattern may be formed over the surface of the translucent diffusion member, or two or more patterns may be formed. In particular, when two or more kinds of patterns are formed, they can be manufactured by double extrusion molding.

As used herein, the term "emissivity" is used to produce a translucent diffusion member by the extrusion or injection molding method using a resin composition, on which a repetitive pattern inscribed in a die of an extrusion or injection molding is produced. It is a quantification of how well it is implemented (transferred), sometimes called "plasticity" or "plasticity rate".

For example, as shown in (a) of Figure 2 by using a mold engraved with a triangular pattern of the height h to produce a translucent diffused member, the height of the pattern transferred to the manufactured translucent diffused member is h ' In the case of the transfer rate can be calculated by the following equation (1).

% Transfer = (h 'transferred to translucent diffusion member) / (h of mold pattern) × 100

The transmissive diffusion member of the present invention preferably has such a transfer rate of 90% or more, and more preferably 99% or more. If the transfer rate is less than 90% may have an image improvement effect, but the desired pattern is not formed, the image improvement effect is insignificant. In addition, an additional light diffusing agent should be used to improve this.

The height h of the pattern is not particularly limited, and may be usually 100 to 1,000 μm, and preferably 20 to 500 μm. However, even in the case of a pattern having a height of 2,000 μm, the translucent diffusion member of the present invention exhibits a transfer rate of 90% or more, so that patterns of various sizes can be formed.

Such a light transmitting diffusion member of the present invention is formed with a pattern having a variety of sizes of 2,000㎛ height, because the transfer rate of the pattern is higher than 90% can reduce the pitch between the pattern and the pattern and emitted from the conventional LED In order to improve the image of the point light source due to the hot-spot of the light, it is possible to implement the image of the surface light source even if a small amount or no light diffusing agent is used.

The translucent diffusion member may have various shapes such as a circle, a square, a triangle, a trapezoid, an octagon, etc. except for the pattern, and a pattern as shown in FIG. 2 may be formed.

The translucent diffusion member may be a closed type in which the surfaces are all integrally connected, or may be an open type in which a part of the surface is cut off.

In addition, the translucent diffusion member may be a tubular type having a long length in the longitudinal direction (mounting direction of the LED element), and may be a direct type having a long length in the width direction (the direction forming 90 ° with the mounting direction of the LED element).

3 is a perspective view of a translucent diffusion member according to an embodiment of the present invention. The light-transmitting diffusing member of FIG. 3 is formed in the pattern as shown in FIG.

4 is an enlarged perspective view of the surface of the light transmitting diffusing member having a three-dimensional shape according to an embodiment of the present invention. The three-dimensional translucent diffusion member is preferably manufactured by injection molding, and can lead to a more optimized optical design.

The thickness of the light-transmissive diffusing member is not particularly limited, and is preferably 0.5 to 2 mm, preferably 1.0 to 1.5 mm, in consideration of workability such as strength and handleability. In addition, the thickness may be the same or different throughout the cross section of the light transmitting diffusion member.

LED lamp of the present invention is characterized in that the light-transmissive diffusion member is provided.

In the present invention, since the LED lamp is well known to those skilled in the art of the present invention, a detailed description of each configuration is omitted.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Example 1

100 parts by weight of a polypropylene homopolymer resin having a linear expansion coefficient of 150 ppm / ° C and a melt flow index of 4.5 g / min, 0.05 part by weight of 2,4-dihydroxybenzophenone as an ultraviolet absorber, and piperidinyl ester light stabilizer 0.05 A weight part and 0.10 part by weight of triphenyl phosphite as a heat stabilizer were mixed using a Henschel mixer to prepare a resin composition for a light transmissive diffusion member.

The prepared composition was extruded at 200-260 ° C. to prepare a light-transmitting diffused member having a pattern. In this case, a mold having a height of 250 μm and engraved with a pattern as shown in FIG.

Example 2

It carried out in the same manner as in Example 1, using a mold having a height of 2,000㎛ engraved pattern of the shape as shown in Fig. 2 (a).

Example 3

The same process as in Example 1, but the height was 81㎛ and 254㎛, respectively, was used a metal mold engraved with a pattern as shown in (c) of FIG.

Example 4

In the same manner as in Example 1, a random copolymer resin of 90% by weight of propylene monomer and 10% by weight of 1-butene monomer was used instead of the polypropylene resin.

Example 5

It carried out similarly to Example 1, but used 0.05 weight part of sorbitol-type nucleating agents (NA-11, Asahi telephone company) further.

Comparative Example 1

In the same manner as in Example 1, polycarbonate resin was used instead of polypropylene resin.

Comparative Example 2

In the same manner as in Example 1, polystyrene resin was used instead of polypropylene resin.

Comparative Example 3

In the same manner as in Example 1, polymethyl methacrylate resin was used instead of the polypropylene resin.

Comparative Example 4

In the same manner as in Example 1, polycarbonate resin was used instead of polypropylene resin, and 3 parts by weight of silica was used as the light diffusing agent.

Test Example

The physical properties of the light-transmissive diffusing member prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1 below.

(1) cross section

The cross section of the prepared light transmitting diffuser was analyzed at 50 × times using an optical microscope.

(2) Transfer rate (%)

Equation 1 was calculated using the height of the pattern engraved on the mold used for extrusion molding and the height of the pitch transferred to the produced light-transmitting diffusion member.

 [Equation 1]

% Transfer = (h 'transferred to translucent diffusion member) / (h of mold pattern) × 100

(3) image improvement

After mounting the LED module to the prepared light transmitting member, the image of the light source was visually observed and evaluated based on the following criteria.

○: surface light source is realized without any point light source.

(Triangle | delta): Some point light source exists.

X: Many point light sources exist.

division Resin (part by weight) % Transfer Image enhancement PP PC PS PMMA Example 1 100 - - - ≥99 ○ Example 2 100 - - - ≥99 ○ Example 3 100 - - - ≥99 ○ Example 4 100 - - - ≥99 ○ Example 5 100 - - - ≥99 ○ Comparative Example 1 - 100 - - 66 × Comparative Example 2 - - 100 - 75 × Comparative Example 3 - - - 100 32 × Comparative Example 4 - 100 - - - ○

As shown in Table 1, the light-transmitting diffusing member of Examples 1 to 5 made of a composition containing a polypropylene resin according to the present invention has a transfer rate of 90% or more of the pattern is a point light source when applied as an LED lamp It can be confirmed that it can be improved by the image of the surface light source. This high transfer rate can also be confirmed through FIGS. 5 and 6, regardless of the shape and size of the pattern, it can be seen that more than 90% of the pattern engraved in the mold is transferred to the light transmitting diffuser. In addition, the light transmitting diffusing members of Examples 1 to 5 had an image improvement effect equivalent to that of Comparative Example 4 or more without including a light diffusing agent, and were economical in terms of cost.

On the other hand, the translucent diffusion members of Comparative Examples 1 to 3 using conventional amorphous resins, as shown in Figures 7 to 9, the pattern transfer rate is low, the pattern is not formed well, the image improvement effect was not good.

As described above, the light-transmitting diffusing member of the present invention is applicable to various LED lighting lamps requiring image improvement to a surface light source.

1 is a perspective view of an LED lamp,

2 is a cross-sectional view showing a pattern of the light transmitting diffusion member of the present invention in a plan view,

3 is a perspective view of a light transmitting diffusing member according to an embodiment of the present invention,

4 is a perspective view of a surface of a translucent diffusion member having a three-dimensional shape according to another embodiment of the present invention,

5 is a cross-sectional photograph of a light transmitting diffusion member according to Example 1 of the present invention;

6 is a cross-sectional photograph of a light transmitting diffusing member according to Embodiment 3 of the present invention;

7 to 9 are cross-sectional photographs of the translucent diffusion members according to Comparative Examples 1 to 3 of the present invention, respectively.

Explanation of symbols on the main parts of the drawings

100: LED light 110: translucent diffuse member

120: LED module 121: LED element

122: substrate 130: cap

Claims (9)

Translucent diffusion member for LED which consists of crystalline polypropylene resin and the pattern which has 90% or more of transfer rate was formed. The LED of claim 1, wherein the polypropylene resin is a homopolymer of propylene monomer or a copolymer of propylene monomer and at least one monomer selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-hexene and 1-octene Translucent diffusion member for. The light-transmitting diffusing member for LED according to claim 1, wherein the polypropylene resin has a coefficient of linear expansion of 120 to 170 ppm / 占 폚. The light-transmitting diffusing member for LED according to claim 1, wherein the polypropylene resin has a melt flow index (230 ° C., 2160 g) of 0.5 to 20 g / min. The translucent diffusion member for LEDs of Claim 1 whose transfer rate is 99% or more. The translucent diffusion member for LEDs of Claim 1 whose height of a pattern is 2,000 micrometers or less. The light transmitting diffusion member for LED according to claim 1, further comprising 0.01 to 2 parts by weight of a light diffusing agent based on 100 parts by weight of polypropylene resin. The translucent diffusion member for LEDs of Claim 1 which further contains 0.005-3 weight part of nucleating agents with respect to 100 weight part of polypropylene resins. An LED lamp provided with the light-transmitting diffusing member of any one of claims 1 to 8.

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