JP2012216523A - Edge-light type surface light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light-emitting device capable of improving durability and following expansion of a light guide plate.SOLUTION: The edge-light type surface light-emitting device 1 is provided with at least a light guide plate 2 of a plan-view rectangular shape, a light source 3 arranged along the opposed end faces 2A, 2B of the light guide plate, a substrate 30 on which the light source is fixed, and a housing 4 to surround these, and light from the light source 3 enters from the end faces 2A, 2B of the light guide plate 2 and is reflected in the light guide plate 2 to be emitted from the emitting face 2Y of the light guide plate 2. A pinching mechanism 5 which can pinch the light guide plate, the light source, and the substrate in a direction orthogonal to an intersection between the end faces 2A, 2B and the emitting face 2Y is provided. The pinching mechanism can freely expand and contract in the orthogonal direction, and the pinching distances are widened and shortened following expansion and contraction of the light guide plate. The substrate is installed with a spacer 6 which maintains the spacing of 0.1-0.8 mm between the end face of the light guide plate on the side where the light source is arranged, and the light source.

Description

  The present invention relates to an edge light type surface light emitting device. This surface light-emitting device is useful for lighting bodies used indoors in offices or in vehicles such as bullet trains, etc .; backlight units used in liquid crystal displays;

  The edge light type surface light emitting device generally includes at least a light source, a light guide plate for surface emitting light incident from the light source, and a housing body surrounding and supporting the light source and the light guide plate. As the light guide plate, a resin plate such as (meth) acrylic resin is typically used.

JP 2010-177077 A JP-A-6-186433 JP 2006-185724 A

  By the way, since the light guide plate is made of resin, it expands due to heat from the light source and changes in temperature and humidity under the usage environment. Therefore, conventionally, in consideration of expansion of the light guide plate, a relatively large size for absorbing the expansion in advance between the light guide plate and the light source and / or between the light guide plate and the housing body. The gap was secured.

  However, when a relatively large gap is secured between the light guide plate and the light source in advance, a part of the light from the light source leaks out of the light guide plate, resulting in low luminous efficiency. There is. Further, when a gap is secured in advance between the light guide plate and the housing body, there is a problem that the light guide plate is unstable in the housing body and the light guide plate or the light source may be damaged.

  On the other hand, when there is no gap between the light guide plate and the light source, when an impact is applied to the light guide plate, the impact is directly transmitted to the light source and the light source may be damaged.

  An object of the present invention is to provide an edge light type surface light emitting device that can eliminate all of the above problems.

  The present invention is a resin-made light guide plate having a rectangular shape in plan view, a light source arranged along at least one end face of the light guide plate facing the light guide plate, and opposed to the end face on the side where the light source is arranged. And at least a substrate on which the light source is fixed, a light guide plate, a light source, and a housing body surrounding the substrate, and the light from the light source is disposed on the side of the light guide plate where the light source is disposed. In the edge light type surface light emitting device, which is incident on the light guide plate, reflected in the light guide plate and emitted from the light exit surface of the light guide plate, the light guide plate, the light source, and the substrate are arranged on the side where the light source is disposed. A clamping mechanism that can be clamped in a direction orthogonal to the line of intersection between the end surface and the light exit surface is provided. The space is designed to expand and contract, Optical plate, and the end surface of the light source is arranged side a light source, during, maintaining a gap of 0.1 to 0.8 mm, the spacer is provided, it is characterized in that.

  In addition, it is preferable that this invention has the following specific structures, for example.

(A) A spacer is a resin body provided side by side with the light source on the substrate and formed thicker by a predetermined dimension than the thickness of the light source, and the predetermined dimension is 0.1 to 0.8 mm.

(B) The clamping mechanism is composed of two plate members and an elastic member. The plate member is composed of a vertical plate portion and a horizontal plate portion, and the vertical plate portion is the above-mentioned of the light guide plate. It is provided along the end surface, the horizontal plate portion is provided to extend to the near side of the center of the reflection surface of the light guide plate, and the elastic member has the horizontal plate portion of the two plate members as the reflection surface of the light guide plate. The sandwiching mechanism is configured to sandwich the light guide plate by pulling the two plate members together by the elastic member, and the light guide plate by the elastic force of the elastic member. The above-mentioned sandwiching interval is expanded and contracted with the expansion and contraction.

(C) The elastic member (b) is a spring.

According to the present invention, the following effects can be exhibited.
(1) In the present invention, since the spacer maintains a gap of a certain size between the end face of the light guide plate and the light source, even if an impact is applied to the light guide plate, the impact is directly transmitted to the light source. Therefore, damage to the light source can be prevented. Therefore, the durability of the edge light type surface light emitting device can be improved.

(2) In the present invention, since the size of the gap maintained between the end face of the light guide plate and the light source by the spacer is 0.1 to 0.8 mm, most of the light emitted from the light source leaks. Without entering the end face. Therefore, according to the present invention, it is possible to effectively suppress a decrease in light emission efficiency due to the gap.

(3) In the present invention, since the light source is pushed to the end face of the light guide plate together with the substrate by the clamping mechanism, it is possible to prevent the gap formed by the spacer from expanding. Therefore, the effects (1) and (2) can be reliably exhibited.

(4) In the present invention, when the light guide plate expands, the holding interval of the holding mechanism increases accordingly, and the expansion of the light guide plate is absorbed by the holding mechanism. Therefore, even when the light guide plate is expanded, the light guide plate is maintained in a state of being sandwiched by the sandwiching mechanism and is stably held in the housing body. Therefore, according to the present invention, it is possible to prevent the light guide plate and the light source from being damaged by the expansion of the light guide plate.

(5) In the present invention, even when the light guide plate expands, the light source is pushed toward the end surface by the clamping mechanism together with the substrate, and the spacer causes 0 between the end surface of the light guide plate and the light source. A gap with a constant dimension of 1 to 0.8 mm is maintained. Therefore, even if the light guide plate expands, the light emitted from the light source enters the end face with almost no leakage. Therefore, according to the present invention, even when the light guide plate expands, it is possible to effectively suppress a decrease in light emission efficiency due to the gap.

It is sectional drawing of the edge light type surface emitting device of one Embodiment of this invention. It is a principal part enlarged view of FIG. It is a perspective view of the light source etc. of the apparatus of FIG. It is a top view of the clamping mechanism of FIG. It is a top view of the light-guide plate of the apparatus of another embodiment of this invention. It is a principal part enlarged view of FIG. It is a perspective view of another example, such as a light source. It is a perspective view of another example, such as a light source. It is a front view which shows arrangement | positioning of the spacer of the specific example of this invention.

  FIG. 1 is a cross-sectional view of an edge light type surface light emitting device according to an embodiment of the present invention. The surface light emitting device 1 includes at least a light guide plate 2, a light source 3, a housing body 4, and a clamping mechanism 5.

  The light guide plate 2 is a rectangular plate in plan view. The light guide plate 2 is made of resin as a main component. As the resin, for example, at least one selected from the group consisting of (meth) acrylic resin, polystyrene resin, polyolefin resin, polycarbonate resin, polyvinyl chloride resin, and (meth) acrylic acid ester-styrene resin is preferable, Particularly preferred is a (meth) acrylic resin. These resins may be used as a mixture of two or more, or may be used so as to laminate two or more. The thickness of the light guide plate 2 is usually 1 to 10 mm, preferably 1.5 to 8 mm, and more preferably 2 to 5 mm. If the light guide plate 2 is too thin, the light from the light source 3 may be difficult to be incident. If the light guide plate 2 is too thick, the light emission efficiency may be insufficient. Is too heavy, so it is not preferable that it is too thin or too thick.

  An irregular reflection layer 21 is formed on the reflection surface 2 </ b> X of the light guide plate 2. The irregular reflection layer 21 is formed by subjecting the reflective surface 2X to direct processing with a laser in a dot shape or a stripe shape, screen printing or vapor deposition of ink, or ink jet printing. Yes. In particular, a dot shape is preferable. As a form of a dot, for example, a substantially circular shape, a substantially triangular shape, a substantially rectangular shape, a substantially hexagonal shape and the like are preferable. As a method of forming the irregular reflection layer 21 in the form of dots, (1) a method of applying unevenness to the portion corresponding to the dots or attaching ink or the like, and (2) a portion of the ground other than the dots On the other hand, there is a method of performing uneven processing or attaching ink or the like. The method (1) is referred to as “positive pattern”, and the method (2) is referred to as “negative pattern”. In the case of a positive pattern, the dot distribution is preferably such that the area occupied by the dots per unit area gradually increases from the end faces 2A and 2B toward the center. In the case of a negative pattern, It is preferable that the area occupied by dots per unit area gradually decreases from the end faces 2A and 2B toward the center.

  A reflective film 22 is further provided on the surface of the irregular reflection layer 21. The thickness of the reflective film 22 is usually 50 to 400 μm. As the reflective film 22, for example, a low-foamed film made of white polyester, a film made of glass or plastic, and a metal having a high reflectance deposited thereon can be used.

  A light diffusion plate 23 is installed on the light exit surface 2Y side of the light guide plate 2. The light diffusion plate 23 is a plate having a light diffusion function or a light collecting function. The light diffusing plate 23 is a plate made of a resin composition containing a light diffusing agent, a plate made of a resin composition and having a concavo-convex shape on the surface, or a resin composition containing a light diffusing agent and a surface. It is comprised with the board | plate with which uneven | corrugated shape was given to. As resin which comprises the light diffusing plate 23, it selects from the group which consists of (meth) acrylic resin, polystyrene resin, polyolefin resin, polycarbonate resin, polyvinyl chloride resin, and (meth) acrylic acid ester-styrene resin, for example. At least one type is preferable, and a (meth) acrylic resin is particularly preferable. These resins may be used as a mixture of two or more, or may be used so as to laminate two or more. Examples of the light diffusing agent that can be included in the light diffusion plate 23 include organic fine particles such as acrylic crosslinked beads and (meth) methyl acrylate-styrene copolymer (MS) crosslinked beads, silica, titanium oxide, Inorganic fine particles such as barium sulfate can be used, and two or more of these may be used simultaneously. In particular, organic fine particles are preferable. Similar to the light guide plate 2, the light diffusion plate 23 may be a rectangular plate in plan view. The thickness is usually about 0.1 to 5 mm, preferably 0.15 to 4 mm. If the light diffusing plate 23 is too thin, wrinkles are likely to occur in the light diffusing plate 23 itself. If the light diffusing plate 23 is too thick, the entire surface light emitting device becomes heavy. It is not preferable. Also, a clear protective plate (not shown) having a rectangular shape in plan view is installed on the light exit surface 2Y side of the light diffusing plate 23 so as to cover the light diffusing plate 23 in order to suppress the generation of wrinkles on the light diffusing plate 23. It is preferable to do this.

  FIG. 2 is an enlarged partial view of the light source 3 and the like shown in FIG. A plurality of light sources 3 are arranged along the long side end faces 2A, 2B of the light guide plate 2 facing each other. As the light source 3, an LED, a fluorescent lamp, a cold cathode tube or the like can be used, and in particular, an LED can be preferably used.

  FIG. 3 is a perspective view of the light source 3 and the like. The light sources 3 are fixed to the substrate 30 facing the end surfaces 2A and 2B of the light guide plate 2 at equal intervals. In the present invention, the spacer 6 is further fixed to the substrate 30. The spacer 6 is arranged alongside the light source 3 between the adjacent light sources 3. The spacers 6 are also fixed to the substrate 30 at equal intervals.

  The spacer 6 is a plate made of resin. Examples of the resin include silicone rubber, acrylic rubber, nitrile rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber, styrene-butadiene rubber, fluorine rubber, polyolefin resin, polyvinyl chloride resin, polytetrafluoroethylene resin, nylon resin, Polycarbonate resin, epoxy resin, etc. can be used. As the resin constituting the spacer, even when the light guide plate 2 expands due to heat or moisture absorption, a suitable position of the light guide plate (that is, a suitable distance between the light source and the light guide plate) can be maintained, and illumination A resin that can have a certain degree of elasticity is preferred so that no distortion occurs. Moreover, you may give a predetermined process to the surface of a spacer. For example, when the surface of the spacer is processed to impart lubricity, it is possible to prevent rubbing in the parallel direction due to the difference in expansion between the light source and the light guide plate. The spacer is made of a transparent resin having a high light transmittance or a white resin having a high light reflectance in order to efficiently use light emitted from the light source to the light guide plate. Is preferred.

  The thickness Ts of the spacer 6 is set to be thicker by a predetermined dimension T than the thickness Tk of the light source 3. The predetermined dimension T is 0.1 to 0.8 mm. Thereby, as shown in FIG. 1, a gap 10 is formed between the end surfaces 2 </ b> A, 2 </ b> B and the light source 3 in a state where the end surfaces 2 </ b> A, 2 </ b> B of the light guide plate 2 are in contact with the spacer 6. .

  The housing body 4 is configured to surround and support the light guide plate 2, the light source 3, and the clamping mechanism 5.

  FIG. 4 is a plan view of the clamping mechanism 5 of FIG. The sandwiching mechanism 5 can sandwich the light guide plate 2, the light source 3, and the substrate 30 in a direction N orthogonal to the intersection line M between the end surfaces 2 </ b> A and 2 </ b> B on the side where the light source is disposed and the light exit surface 2 </ b> Y. . That is, the sandwiching mechanism 5 sandwiches the light guide plate 2 from both end surfaces 2A and 2B while pushing the light source 3 together with the substrate 30 toward the end surfaces 2A and 2B. Further, the clamping mechanism 5 can expand and contract in the orthogonal direction N, and the clamping interval W expands and contracts as the light guide plate 2 expands and contracts.

  Specifically, the clamping mechanism 5 includes two plate members 51 and 52 and an elastic member 53. As the elastic member 53, a spring is used. The plate member 51 includes a vertical plate portion 511 and a horizontal plate portion 512. The vertical plate portion 511 is provided along the end surface 2 </ b> A of the light guide plate 2. The horizontal plate portion 512 is provided to extend to the near side of the center of the reflection surface 2X of the light guide plate 2. Similarly, the plate member 52 includes a vertical plate portion 521 and a horizontal plate portion 522. The vertical plate portion 521 is provided along the end surface 2 </ b> B of the light guide plate 2. The horizontal plate portion 522 is provided so as to extend to the front of the center of the reflection surface 2X of the light guide plate 2. The elastic member 53 connects the horizontal plate portion 512 and the horizontal plate portion 522 at the center of the reflective surface 2X of the light guide plate 2. In FIG. 4, the elastic member 53 connects the horizontal plate portion 512 and the horizontal plate portion 522 at two locations. However, this is only an example, and the number and positions of the connection locations are as shown in FIG. 4. It is not limited to this example, and is set as appropriate. Specifically, the elastic member 53 has one end connected to a hook 513 provided on the horizontal plate portion 512 and the other end connected to a hook 523 provided on the horizontal plate portion 522. As a result, the clamping mechanism 5 is configured to sandwich the light guide plate 2 by pulling the plate member 51 and the plate member 52 together by the elastic member 53, and the light guide plate by the elastic force of the elastic member 53. With the expansion and contraction of 2, the sandwiching interval W is expanded or contracted. In addition, the board | substrate 30 with which the light source 3 was fixed is attached inside the vertical board part 511,521. Therefore, the sandwiching mechanism 5 sandwiches the light guide plate 2 while pushing the light source 3 together with the substrate 30 toward the end surfaces 2A and 2B.

  The housing body 4 supports the light guide plate 2 and the clamping mechanism 5 by the upward support portion 41 and the downward support portion 42 so as to be gripped from above and below. Thereby, the light guide plate 2 is stably supported in the housing body 4, and the holding mechanism 5 is maintained in a horizontal state.

  In the surface light emitting device 1 having the above-described configuration, the light emitted from the light source 3 enters the light guide plate 2 through the gap 10 through the end surface 2A and the end surface 2B, and is repeatedly reflected in the light guide plate 2 while being diffusely reflected. The light is diffusely reflected by the 21 dots and reflected by the reflective surface 2X and the reflective film 22 between the dots, and is diffused and emitted from the light exit surface 2Y by the light diffusion plate 23. That is, the light exit surface 2Y emits light by the light emitted from the light source 3. Thereby, the surface emitting device 1 exhibits a surface emitting function. The surface light-emitting device 1 having the above configuration has a sufficient illuminance, and is particularly suitable as an indoor lighting device.

By the way, in the surface light-emitting device 1 of the said structure, the light source 3 is pushed toward end surface 2A, 2B of the light-guide plate 2 with the board | substrate 30 by the clamping mechanism 5. FIG. Thus, the end surfaces 2A and 2B are in contact with the spacer 6. Therefore, a gap 10 having a predetermined dimension T, that is, a fixed dimension, is maintained between the end face 2A and the light source 3 and between the end face 2B and the light source 3. Therefore, the following effects can be exhibited.
(1) Since the gap 10 exists, even if an impact is applied to the light guide plate 2, the impact is not directly transmitted to the light source 3, so that the light source 3 can be prevented from being damaged. Therefore, the durability of the surface light emitting device 1 can be improved.
(2) Since the gap 10 is maintained at a constant size of 0.1 to 0.8 mm, the light emitted from the light source 3 is incident on the end faces 2A and 2B with almost no leakage even after passing through the gap 10. Therefore, it is possible to effectively suppress a decrease in light emission efficiency due to the gap 10.

  On the other hand, the light guide plate 2 expands due to heat from the light source and changes in temperature and humidity under the usage environment. However, in the surface light emitting device 1 having the above configuration, when the light guide plate 2 expands in the direction of the arrow A, the elastic member 53 extends so that the sandwiching interval W increases accordingly. That is, the expansion of the light guide plate 2 is absorbed by the elastic member 53. Therefore, even when the light guide plate 2 is expanded, the light guide plate 2 is maintained in a state of being sandwiched by the sandwiching mechanism 5 and is stably held in the housing body 4. Therefore, the light guide plate 2 and the light source 3 can be prevented from being damaged by the expansion of the light guide plate 2. Moreover, even when the light guide plate 2 expands, the light source 3 is pushed toward the end surfaces 2A and 2B by the clamping mechanism 5 together with the substrate 30, so that the gap 10 having a predetermined dimension T is maintained. Therefore, even if the light guide plate 2 expands, the light emitted from the light source 3 enters the end faces 2A and 2B with almost no leakage. Therefore, even when the light guide plate 2 expands, it is possible to effectively suppress a decrease in light emission efficiency due to the gap 10.

  The surface light emitting device 1 having the above configuration may adopt the following modified configuration.

(1) FIG. 5 is a plan view of the light guide plate 2. In the light guide plate 2, a notch 70 is formed in the center of the end faces 2C and 2D. The notch 70 is provided with a guide member 7. FIG. 6 is an enlarged plan view of the guide member 7 on the end face 2C side, but the same applies to the guide member 7 on the end face 2D side. The guide member 7 is fixed to the inner wall of the housing body 4 and includes a base portion 71, a convex portion 72, and a spring 73. The convex part 72 is inserted in the notch part 70. The spring 73 is interposed between the end surface 2 </ b> C and the base portion 71. In such a configuration, the expansion of the light guide plate 2 in the direction of arrow B is guided by the protrusion 72 and absorbed by the spring 73. Therefore, the light guide plate 2 is stably held in the housing body 4 even when expanded in the direction of arrow B.

(2) The spacers 6 may be disposed at both ends of the substrate 30 as shown in FIG.
(3) The spacers 6 may be arranged above and below the light source 3 as shown in FIG.
(4) The spacer 6 may be made of a material other than resin, for example, metal, and is not limited to a plate body but may be a block body.

(5) The light source 3 may be provided only on one of the end surfaces 2A and 2B of the light guide plate 2.
(6) As the elastic member 53, for example, a rubber string or the like other than the spring may be used.

[Concrete example]
It is the surface emitting device 1 which has the structure of FIG. The specific configuration of each part is as follows.
Light guide plate 2: A (meth) acrylic resin plate having a product name “SUMIPEX E005” manufactured by Sumitomo Chemical Co., Ltd. was used. The dimensions are 3 mm in thickness, 250 mm in width, and 600 mm in length. “SUMIPEX” is a registered trademark of Sumitomo Chemical Co., Ltd.
-Diffuse reflection layer 21: formed by printing a reflective ink by a screen printing method. The reflective ink is composed of volatile curable resin ink, acrylic beads, silica fine particles, and phosphor. The print pattern is a negative pattern, the dot shape is substantially circular, and the dot pitch (center-to-center distance) is constant. The negative pattern is set so that the printed portion per unit area is small near the light source and increases toward the center so that the luminance when used as illumination is uniform.
Reflective film 22: The product name “E60” manufactured by Toray Industries, Inc. was used.
-Light diffusion plate 23: The product name “GM7” manufactured by Kimoto Co., Ltd. was used. The thickness is 180 μm. Furthermore, an acrylic resin plate having a product name “SUMIPEX E000” manufactured by Sumitomo Chemical Co., Ltd. was used as a clear protective plate. The thickness is 1.5 mm.
LED (light source 3): disposed on the long side end faces 2A, 2B of the light guide plate 2. 84 pieces were arranged on the substrate 30 at equal intervals.
Spacer 6: As shown in FIG. 9, five LEDs are arranged on the substrate 30 at equal intervals for every 21 LEDs.
-Seven predetermined dimensions T were set. That is, they were set to 0 mm, 0.16 mm, 0.32 mm, 0.47 mm, 0.77 mm, and 1.12 mm, and these were designated as first to sixth specific examples.

[performance test]
The surface light emitting device 1 of each of the above specific examples was installed at the center of a large integrating sphere for measuring total luminous flux. Then, the surface light emitting device 1 was caused to emit light by applying power of 37.4 W, and the total luminous flux was measured with a diode array spectroscope.
The results are shown in Table 1.
As a large integrating sphere for measuring the total luminous flux, a model 1500 type spherical luminous meter manufactured by Nemtech Co., Ltd. was used. As a diode array spectrometer, DAS-2100 manufactured by Labsphere was used.

[Conclusion]
As is clear from Table 1, the surface light emitting devices 1 of the second to fifth specific examples are excellent in luminous efficiency. Therefore, in the surface light emitting device 1 of the present invention, the predetermined dimension T of the gap 10 is set to 0.1 to 0.8 mm.

  The edge light type surface light emitting device of the present invention can improve durability, and can follow the expansion of the light guide plate, and therefore has great industrial utility value.

  DESCRIPTION OF SYMBOLS 1 Edge light type surface emitting device 10 Crevice 2 Light guide plate 2A, 2B End face 3 Light source 30 Substrate 4 Housing body 5 Holding mechanism 51, 52 Plate member 511, 521 Vertical plate portion 512, 522 Horizontal plate portion 53 Elastic member 6 Spacer

Claims (4)

A resin-made light guide plate having a rectangular shape in plan view;
A light source disposed along at least one end surface of the opposing end surfaces of the light guide plate;
A substrate disposed opposite to the end surface on the side where the light source is disposed, and having the light source fixed thereto;
A housing body surrounding the light guide plate, the light source, and the substrate;
An edge light in which light from the light source is incident on the end surface of the light guide plate on the side where the light source is disposed, reflected in the light guide plate, and emitted from the light exit surface of the light guide plate. In the mold surface light emitting device,
A light guide plate, a light source, and a substrate are provided with a holding mechanism that can hold the light guide plate, the light source, and the substrate in a direction orthogonal to the line of intersection between the end face on the side where the light source is disposed and the light exit surface,
The clamping mechanism is extendable in the orthogonal direction, and the clamping interval is expanded and contracted with the expansion and contraction of the light guide plate.
The substrate is provided with a spacer that maintains a gap of 0.1 to 0.8 mm between the light source plate and the end surface on the side where the light source is disposed, and the light source.
An edge light type surface light emitting device characterized by the above. The spacer is a resin body that is provided side by side with the light source in the substrate, and is formed thicker by a predetermined dimension than the thickness of the light source,
The predetermined dimension is 0.1 to 0.8 mm.
The edge light type surface emitting device according to claim 1. The clamping mechanism is
It consists of two plate members and an elastic member,
The plate member is composed of a vertical plate portion and a horizontal plate portion,
The vertical plate portion is provided along the end face of the light guide plate,
The horizontal plate portion is provided to extend to the front near the center of the reflection surface of the light guide plate,
The elastic member connects the horizontal plate portions of the two plate members at the center of the reflection surface of the light guide plate,
The clamping mechanism is configured to clamp the light guide plate by pulling the two plate members toward each other by an elastic member, and the above-mentioned clamping mechanism is expanded and contracted by the elastic force of the elastic member. The clamping interval is designed to expand and contract,
The edge light type surface emitting device according to claim 1. The elastic member is a spring;
The edge light type surface emitting device according to claim 1.

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