KR20130096140A - Resin composition for inducing light diffusion - Google Patents

Abstract

PURPOSE: A resin composition for inducing light diffusion is provided to improve heat resistance property, by removing a light guide plate and using a resin layer which uses oligomer as a chief ingredient. CONSTITUTION: A light emitting diode (LED) light source (111) emits a light. At least more than one LED light source is arranged on a printed circuit board (110). A resin layer (140) surrounds the LED light source. The resin layer disperses the light of the light source emitted toward the side. The resin layer performs the function of the conventional light guide plate.

Description

Resin composition for light diffusion induction {RESIN COMPOSITION FOR INDUCING LIGHT DIFFUSION}

The present invention can remove the structure of the light guide plate to thin the structure of the lighting device, to ensure the light efficiency, and to increase the productivity and manufacturing efficiency resin composition for inducing light diffusion, the manufacturing process and the illumination produced thereby Relates to a device. Furthermore, the present invention relates to a backlight unit, a liquid crystal display device, and a vehicle lamp device using the above-described lighting device.

A device for implementing illumination by guiding light emitted from a light source is variously required in an illumination lamp, a vehicle lamp, a liquid crystal display, and the like. In such a lighting device, the technique of thinning the structure of the equipment and the structure of increasing the light efficiency are recognized as the most important technologies.

An example in which the lighting device is applied will be described below with reference to a liquid crystal display.

A liquid crystal display (LCD) is a display device that can control a desired image by individually supplying data signals according to image information to pixels arranged in a matrix form and adjusting light transmittance of the pixels. Since it does not emit light, it is designed to display an image by installing a lamp device on its back.

Referring to FIG. 1, such a lamp device has a flat light guide plate 30 disposed on a substrate, and a plurality of side surface type LEDs 10 (only one shown) are arranged on the side of the light guide plate 30 in an array form. do.

The light L incident on the light guide plate 30 from the LED 10 is reflected by the reflective sheet 40 in a fine reflection pattern provided on the bottom surface of the light guide plate 30 and is emitted from the light guide plate 30, 30 to provide light to the LCD panel 50 on the upper side. Such a lamp device includes a diffusion sheet 31, a prism sheet 32, 33, a protective sheet 34, and the like between the light guide plate 30 and the LCD panel 50, as illustrated in FIG. 1. It may be formed of a structure that further adds a plurality of optical sheets.

The lamp device illuminates the light evenly so that the display image can be seen on the back of the LCD which does not emit light by itself, and the light guide plate performs the brightness and uniform illumination function of the lamp device. It is one of the plastic molded lens that uniformly transmits the light emitted from the light source (LED) to the whole LCD surface. Therefore, the light guide plate is basically used as an essential component of such a lamp device, but the thickness of the light guide plate itself shows a limitation in reducing the thickness of the entire product, and in the case of a large area lamp device This causes a problem of deterioration of image quality.

The present invention has been made to solve the above problems, an object of the present invention is to remove the light guide plate essential to the structure of a general lighting device, and to form a structure for inducing a light source using a resin layer containing oligomer as a main component, It is possible to reduce the number of light sources, and in particular, to provide a lighting device capable of realizing excellent heat resistance and light characteristics by minimizing a change in luminance during continuous high temperature lighting.

In addition, the overall thickness of the lighting device is reduced, and the tensile strength, the reliability of constant temperature and humidity, heat-resistant reliability is secured to provide a lighting device and a liquid crystal display device using the same to increase the degree of freedom of design and design. There is another purpose.

As a means for solving the above problems, the present invention provides a resin composition for inducing light diffusion comprising an oligomer, a monomer, and an additive.

In addition, the oligomer may be a urethane acrylate oligomer.

In addition, the monomer may be a mixture including IBOA (Isobornyl Acrylate), HBA (Hydroxybutyl Acrylate), and HEMA (Hydroxyethyl Methacrylate).

In addition, the additive may be a mixture including a photoinitiator and an antioxidant.

In addition, the resin composition for inducing light diffusion may comprise 10 to 21% by weight of oligomer, 30 to 63% by weight of monomer, 1.5 to 6% by weight of additive, and remaining amount of solvent.

Here, the monomer may be a mixture including 10-21 wt% of IBOA (Isobornyl Acrylate), 10-21 wt% of HBA (Hydroxybutyl Acrylate), and 10-21 wt% of HEMA (Hydroxyethyl Methacrylate).

In addition, the additive may be a mixture containing 1 to 5% by weight of photoinitiator, and 0.5 to 1% by weight of antioxidant.

Further, the present invention includes a plurality of LED light source formed on a printed circuit board; and a resin layer stacked on the LED light source, to induce the emitted light to the front; wherein the resin layer comprises an oligomer Provided is a lighting device made of synthetic resin.

In addition, the resin layer may be configured to include the oligomer 10-21%, monomer 30-63%, additives 1.5-6%.

In addition, the oligomer may be a urethane acrylate oligomer.

In addition, the monomer, IBOA (Isobornyl Acrylate) 10-21%, HBA (Hydroxybutyl Acrylate) 10-21%, HEMA (Hydroxyethyl methacrylate) may be made of a mixture containing 10-21%.

In addition, the additive may be a mixture containing 1-5% photoinitiator, 0.5-1% antioxidant.

In the above-described lighting apparatus according to the present invention, the LED light source may be a side view light emitting diode (Side View LED), and may further include a reflective film having a reflective pattern formed on the printed circuit board. .

In addition, the lighting apparatus according to the present invention may be implemented in a structure further comprising a diffusion plate formed on the upper surface of the resin layer, the printed optical pattern for blocking or reflecting the emitted light.

In particular, the resin layer may be configured to further include a bead (bead) to increase the reflection of light relative to the total resin layer weight 0.01 ~ 0.3%.

The optical pattern may include a diffusion pattern formed using a light shielding ink including at least one material selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon, and Al or Al and TiO ₂ . It may be made of a superimposition structure of the light shielding pattern using a light shielding ink containing a mixture.

In addition, the reflective pattern may be formed by applying a reflective ink including any one of TiO ₂ , Al ₂ O ₃ .

It will be apparent that the liquid crystal display device can be implemented using the lighting device according to the present invention. Specifically, a side light emitting diode (Side View LED) is used as a light source, and the resin layer according to the present invention, which is stacked in a structure for accommodating the light source, is used as the light guide plate, but is laminated on the printed circuit board on the upper surface. And a reflecting film having a reflective pattern formed thereon and a diffuser plate formed on an upper surface of the resin layer and having an optical pattern for shielding or reflecting the emitted light. And, of course, it may further include a prism sheet or a protective sheet laminated on the diffusion plate.

According to the present invention, the number of light sources can be reduced by removing a light guide plate essential to the structure of a general lighting device and inducing a light source by using a resin layer containing oligomers as a main component, and particularly in the case of sustaining high temperature lighting. The present invention provides a lighting apparatus that can realize excellent heat resistance and optical characteristics by minimizing a change in luminance.

In addition, the overall thickness of the lighting device can be thinned, and the lighting device capable of increasing the degree of freedom in design and the product having the tensile strength, the reliability of the constant temperature and humidity, and the heat resistance, and the liquid crystal display device using the same can be provided. .

1 is a conceptual diagram showing the structure of a lighting apparatus according to the prior art.
2A is a conceptual view illustrating main parts of a structure of a lighting apparatus according to the present invention.
Figure 2b is a state diagram showing the function of the resin layer and the beads of the lighting apparatus according to the present invention.
Figure 3 is a table showing an embodiment of the composition constituting the resin layer according to the present invention.
4A to 4C illustrate experimental data of characteristics of the resin layer according to the present invention and characteristics of the resin layer composed of a general polymer.
5 is a graph comparing the rate of change of luminance during high temperature operation of the lighting apparatus and the general lighting apparatus according to the present invention.
6 is an exemplary view showing an optical pattern according to the present invention.
7 is an exemplary view showing a reflection pattern according to the present invention.
8 is a view showing an operating state of the lighting apparatus according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description with reference to the accompanying drawings, the same reference numerals denote the same elements regardless of the reference numerals, and redundant description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention removes the light guide plate from the structure of a conventional lighting device, and forms it as a resin layer containing oligomer as a main component, thereby minimizing the change in luminance at high temperature, and innovatively reducing the overall thickness of the lighting device, The main idea is to provide a structure that can reduce the cost.

In addition, the illumination device according to the present invention is not limited to being applied to the backlight unit of the above-described liquid crystal display device. That is, the present invention is applicable to a variety of lamp devices requiring illumination, such as a vehicle lamp, a home lighting device, and an industrial lighting device. Vehicle lamps can be applied to headlights, indoor and outdoor lighting, rear lights, of course.

2A and 2B are conceptual views illustrating main parts of a lighting apparatus according to the present invention. Referring to the drawings, the LED light source 111 is arranged on the printed circuit board 110 in at least one number to emit light, in a preferred embodiment of the present invention a side view LED (Side View LED) Can be used. That is, the direction of the light emitted from the LED light source 111 does not go straight to the top, but may use a light source having a structure that exits toward the side. In addition, since the placement method is directly arranged using the side-type light emitting diode, the total thickness of the lighting apparatus can be innovatively reduced while reducing the total number of light sources by utilizing the resin layer that implements the light diffusion and reflection function .

The resin layer 140 is stacked in a structure surrounding the LED light source 111 and performs a function of dispersing light of the light source emitted laterally. That is, the resin layer 140 may perform a function of the conventional light guide plate. It is needless to say that the resin layer can be basically made of any resin capable of diffusing light.

3 is a diagram showing a preferred embodiment of the composition for forming a resin layer according to the present invention in the above-described structure.

As the main material of the resin layer according to one embodiment of the present invention, a resin (oligomer type) containing urethane acrylate oligomer as a main raw material may be used. For example, urethane acrylate oligomers that are synthetic oligomers can be used.

Of course, the low-boiling dilution-type reactive monomer IBOA (Isobornyl acrylate), HBA (Hydroxybutyl Acrylate), HEMA (Hydroxyethyl methacrylate) may further include a monomer mixed, photoinitiator (such as 1-hydroxycyclohexyl phenyl) as an additive -ketone), Diphenyl (2,4,6-trimethylbenzoyl phosphine oxide), or an antioxidant can be mixed.

More specifically, the resin layer may be formed of a composition comprising 10 to 21% oligomer, 30 to 63% monomer, 1.5 to 6% additive.

In this case, the monomer may be composed of a mixture of IBOA (Isobornyl Acrylate) 10-21%, HBA (Hydroxybutyl Acrylate) 10-21%, HEMA (Hydroxyethyl Methacrylate) 10-21%. The additive may be added to 1 to 5% of the photoinitiator to perform a function of initiating photoreactivity, and may be formed of a mixture that may improve the yellowing phenomenon by adding 0.5 to 1% of the antioxidant.

Formation of the resin layer using the above-described composition forms a resin layer such as UV resin instead of the light guide plate, so that the effect of the conventional light guide plate can be substituted, and instead the refractive index, thickness can be adjusted, and the composition described above It can be used to meet both the adhesive properties and reliability and mass production speed.

In particular, the formation of the resin layer according to the present invention is preferably made through the following special process.

That is, the resin layer according to the present invention uses a urethane acrylate oligomer as a main material, the main reaction at a UV curing wavelength of 300 ~ 350㎛, using a mercury lamp and a metal (gallium) lamp of 400㎛ Wavelength and secondary low pressure curing process, but in the second low pressure curing process, by adding N ₂ to increase the surface adhesion and curing rate to adjust the curing balance (flexible), excellent adhesion In addition, maintaining the refractive index of the PMMA light guide plate can overcome the limitation of the light guide plate.

Particularly, if nitrogen purging is not performed during the oligomer curing, surface wrinkles and cracks may occur due to internal curing and surface hardening balance. It is more preferable to enable hardening.

Hereinafter, the results of comparative experiments on the properties of the resin layer formed only of the polymer and the resin layer mixed with the monomer as a main component of the oligomer according to the present invention as shown in FIG. 3 will be described.

1. Adhesion (tensile strength) reliability test

This test is a test to measure the tensile strength by using a thin film tensile tester (Instron, USA), the coating thickness of the resin layer on the upper and lower grips of the device to 1300㎛, horizontal x vertical (50mmX100mm) respectively As the upper grip is raised, the result of comparing and observing the load applied to the load cell in real time is shown (see FIG. 4A). (Test conditions are 0.1m per minute)

{Table 1}

Referring to the above test results, in general, the oligomer single type is lower than the polymer single type in terms of tensile strength, but has excellent results in terms of optical properties such as a luminance change rate to be described later.

2. Constant temperature and humidity reliability test

In this test, a constant temperature and humidity chamber (THB (Temperature Humidity Bias), THB SH-641 / ESPEC Co., Ltd. (Japan)) was applied to a constant temperature and humidity in the chamber, and the constant temperature and humidity characteristics were compared. The test conditions were maintained at 60 ° C. and 95% humidity for 1000 hours, and then the characteristics were compared. (As shown in FIG. 2, a reflective film and a resin layer formed on the printed circuit board were formed. It was made.

The resin layer was formed on the above-mentioned reflective film with a coating thickness of 1300 μm and a width X length (115 mm × 175 mm), respectively, and after applying the above test conditions, the appearance and lighting tests were compared (see FIG. 4B).

{Table 2}

Referring to the table shown, the resin layer of the oligotype according to the present invention has no abnormality of appearance, the degree of adhesion does not change, but the problem that the yellowing phenomenon of the resin layer of the polymer only occurs in the front portion. In addition, the adhesion characteristics were also bad.

3. Heat resistant reliability test

This test is to evaluate the heat resistance of the product by applying a certain heat in the oven {HT330 / ETAC (Japan)} for a certain time. Test conditions, after 240 hours at 80 ℃, the heat resistance and adhesion properties of the resin layer was compared. In the test method, a coating thickness of 1300 μm and a width X length (115 mm × 175 mm) were respectively formed on the reflective film in FIG. 2, and the appearance and lighting tests were compared after applying the above test conditions (see FIG. 4C). .

{Table 3}

In this test, the resin layer mainly containing the oligomer according to the present invention did not find any abnormality in appearance, and the adhesion degree did not change, but the resin layer of the polymer had a defect in which yellowing phenomenon occurred at the front part.

Comparing the above three characteristic tests, the resin layer having a composition as the main raw material of the oligomer according to the present invention can be found to be more efficient than a single resin layer in various aspects such as tensile strength, constant temperature and humidity characteristics, heat resistance, reliability, adhesion characteristics have.

4. Luminance change rate test by high temperature operation

5 is, the result of testing the reliability according to the high temperature lighting by applying the resin layer according to the present invention, (a) the resin layer applied illumination device according to the present invention (b) a polymer applied illumination device for general optics The results of comparative experiments are shown.

Specifically, by applying a resin layer composed mainly of the oligomer according to the present invention and a resin layer formed of a polymer to the structure of the lighting device according to the present invention shown in Figure 2, at a high temperature lighting reliability test, at 60 ℃ The result of turning on the light source of a lighting device and leaving 1000 Hrs to stand is shown. As shown in the graph of (b), when the general optical polymer is used as the resin layer, the light emitting device having the resin layer according to the present invention exhibits a luminance decrease rate of 52% after 300 hours and room temperature for 4 hours. After the elapse of time reliability, after 6 hours at room temperature, only 6% of the luminance decrease is shown. The above results prove that after 1000 hours reliability test, it has very good heat resistance and optical properties compared to the polymer type.

Referring to the structure of the present invention shown in Figures 2a and 2b, in detail the operation of the configuration of the unique lighting device according to the present invention in combination with the characteristics of the resin layer described above as follows.

In the lighting apparatus according to the present invention, the resin layer 140 may further include a bead 141 to increase diffusion and reflection of light. The beads 141 preferably include 0.01 to 0.3% of the total resin layer weight. That is, the light emitted from the LED in the lateral direction is diffused and reflected through the resin layer 140 and the beads so that the light can travel upward, and the reflective film 120 and the reflective pattern 130 to be described later are provided. As a result, the reflection function can be further promoted. The presence of the resin layer innovatively reduces the thickness occupied by the conventional light guide plate, thereby realizing thinning of the entire product, as well as having a soft material, and thus having a versatility applicable to a flexible display. do.

In addition, the reflective film 120 has a reflective material so as to disperse the light emitted from the light source and at the same time it is more preferably provided with a reflective pattern 130 through white printing to promote the dispersion of light. Do. The reflective pattern may be printed by using a reflective ink including any one of TiO ₂ and Al ₂ O ₃ .

In addition, the diffusion plate 150 serves to diffuse the light emitted through the resin layer 140, in particular, the light is excessively strong so that the optical characteristics deteriorate or yellowish light (yellowish) In order to prevent the optical pattern 151 is preferably formed so that a portion of the shading effect can be implemented. That is, the light shielding pattern may be printed using the light shielding ink so that light does not concentrate.

The optical pattern 151 may be implemented in a manner that is basically printed on the lower surface or the upper surface of the diffuser plate 150, particularly preferably at the position of the LED light source 111 disposed below the diffuser plate It is preferable to arrange | position in the direction in which light exits (pre-direction). That is, it may be disposed on the diffuser plate at a position corresponding to the vertical upper surface or the light exit direction surface of the LED light source.

The optical pattern is not a function to completely block the light but can be implemented so that the light shielding degree or the diffusing degree of the light can be controlled by one optical pattern so as to perform a function of partial shielding and diffusion of light. Furthermore, more preferably, the optical pattern according to the present invention may be implemented as a superimposed printing structure of a complex pattern. The structure of superimposed printing refers to a structure in which one pattern is formed and another pattern is printed on the pattern.

For example, referring to FIG. 6, in implementing the optical pattern 151, at least one selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and Silicon on the bottom surface of the diffusion plate in the light emitting direction. The diffusion pattern 151a formed using the light shielding ink including a material and the light shielding pattern 151b using the light shielding ink containing Al or a mixture of Al and TiO ₂ may be implemented. That is, after the diffusion pattern 151a is formed by white printing on the surface of the diffusion plate, the light shielding pattern 151b may be formed thereon or may be formed in a double structure in the reverse order. Of course, it will be obvious that the formation design of such a pattern can be variously modified in consideration of light efficiency, intensity, and shading ratio.

Alternatively, a light blocking pattern 151b, which is a metal pattern, may be formed in a middle layer in a sequential layer structure, and a triple structure may be formed on the upper and lower portions of the diffusion pattern 151a, respectively. In such a triple structure, it is possible to select and implement the above-described materials. As a preferred example, one of the diffusion patterns is implemented using TiO ₂ having excellent refractive index, and CaCO ₃ having excellent light stability and color sense is used together with TiO _2. It is possible to realize different diffusion patterns, and to secure light efficiency and uniformity through the triple structure of the structure implementing the light shielding pattern using Al having excellent concealment. In particular, CaCO ₃ functions to subtract the exposure of yellow light to finally implement white light, thereby realizing more stable light. In addition to CaCO ₃ , particles such as BaSO ₄ , Al ₂ O ₃ , and silicon beads Larger, similarly structured inorganic materials may be used.

In addition, it is preferable in view of light efficiency that the optical pattern is formed by adjusting the pattern density so that the pattern density is lowered away from the emitting direction of the LED light source.

In addition, in the structure of the lighting apparatus according to the present invention, in particular, in the above-described structure, the present invention is the optical pattern between the resin layer 140 and the optical pattern 151 formed on the surface of the diffusion plate 150 A surface treatment layer (not shown) for flattening the pattern irregularities of the air layer may further include an air layer due to a step generated during adhesion between the optical pattern 151 of the diffusion plate and the resin layer 140 disposed thereunder. In order to eliminate the difference between the dark portion and the bright portion generated by the formation, it is preferable to implement a flattened layer (layer) structure to cover the step of the entire optical pattern 151. In addition, the surface treatment layer is more preferably to improve the adhesion using the same material as the resin layer 140.

7 is a plan view showing the structure of a reflective film and a reflective pattern according to the present invention.

That is, the reflective film 120 according to the present invention is stacked on the printed circuit board, and the LED light source 111 protrudes to the outside through the holes formed on the reflective film. When the LED light source is implemented as a side emitting type structure, the number of light sources can be greatly reduced as described above, and the reflection pattern 130 is implemented to greatly improve the reflectance of the light in order to reduce the reduction rate. This is preferred.

The reflective pattern is preferably formed in the light emission direction of the LED light source, as shown in the example, and may be arranged such that the pattern density increases as the distance from the light emission direction of the LED light source increases. That is, by increasing the pattern density of the second region 132 far from the emission direction than the first region 131 close to the emission direction, the reflectance can be increased. Of course, the structure of the pattern can be implemented in various shapes according to the design intention. In addition, the reflective pattern may be formed by printing using a reflective ink including any one of TiO ₂ and Al ₂ O ₃ .

8 is an operating state diagram showing an operating state of the structure of the lighting apparatus according to the present invention described above.

As shown, the lighting device according to the present invention is emitted from the side-emitting type LED 111 in the lateral direction, the emitted light is reflected and diffused in the resin layer 140 formed instead of the structure of the conventional light guide plate. In particular, the reflection film 120 and the reflection pattern 130 by the reflection efficiency is further increased, it is possible to guide the light forward. The light passing through the resin layer 140 is subjected to a process of being diffused or shielded through the optical pattern 151 formed on the diffusion plate 150, and the light L thus purified is optical such as the prism sheet 160. White light enters the LCD panel through the sheet.

As described above, the lighting apparatus according to the present invention removes the structure of the light guide plate, applies a side light emitting LED as a source of light, diffuses light through the resin layer, and induces light through reflection, thereby reducing the thickness and number of light sources. On the other hand, the luminance reduction and uniformity problems caused by the reduction of the light source can be compensated for by the optical patterns such as the reflection pattern, the light shielding pattern, and the diffusion pattern, thereby realizing the uniformity of image quality.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

110: printed circuit board
111: LED light source
120: reflective film
130: reflection pattern
140: Resin layer
150: diffusion plate
151: optical pattern
151a: diffusion pattern
151b: shading pattern
160: prism sheet

Claims (7)

Resin composition for inducing light diffusion comprising an oligomer, a monomer, and an additive.
The method of claim 1,
The oligomer,
Resin composition for inducing light diffusion which is a urethane acrylate oligomer.
The method of claim 1,
The monomer,
Resin composition for inducing light diffusion, which is a mixture comprising IBOA (Isobornyl Acrylate), HBA (Hydroxybutyl Acrylate), and HEMA (Hydroxyethyl Methacrylate).
The method of claim 1,
Preferably,
Resin composition for inducing light diffusion which is a mixture comprising a photoinitiator and an antioxidant.
5. The method according to any one of claims 1 to 4,
Resin composition for inducing light diffusion comprising 10 to 21% by weight of oligomer, 30 to 63% by weight of monomer, 1.5 to 6% by weight of additive, and residual solvent.
The method of claim 5,
The monomer,
IBOA (Isobornyl Acrylate) 10-21% by weight, HBA (Hydroxybutyl Acrylate) 10-21% by weight, and HEMA (Hydroxyethyl methacrylate) is a mixture containing 10-21% by weight of a resin composition for inducing light diffusion.
The method of claim 5,
Preferably,
Resin composition for inducing light diffusion which is a mixture comprising 1 to 5% by weight of photoinitiator, and 0.5 to 1% by weight of antioxidant.

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