JP2011082037A - Light source module, and electronic equipment equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source module in which light from a light source can be made incident sufficiently on an end face of a light guide body, and connection efficiency can be maintained in a superior state even if the distance between the light source and the end face of the light guide body is more separated than a prescribed distance (even if tolerance becomes large); and to provide an electronic equipment equipped with the light source module. <P>SOLUTION: The light source module 10 includes: the light guide body 20; and an LED (light source) 12 by which the light is made incident at least on one end face in the longitudinal direction in the light guide body 20, wherein at a coupling part between the LED 12 and the light guide body 20, a regular reflection members 30 is installed. The regular reflection member 30 may be installed on the side where the light is emitted from the light guide body 20 at the coupling part, may be installed on the side opposite to the side where the light is emitted from the light guide body 20 at the coupling part, and may be installed on both sides. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is used, for example, in a backlight including a side edge (also referred to as a sidelight) type light guide that emits light from a light source in a planar shape by a light guide to reduce the thickness in a liquid crystal display device. The present invention relates to a light source module and an electronic device including the same.

  In recent years, in order to reduce the thickness of a liquid crystal display device, a backlight including a side edge (also referred to as a sidelight) type light guide plate that emits light from a light source in a planar shape by a light guide plate is frequently used.

  As such a side edge type light guide plate, for example, in Patent Document 1, a light guide plate composed of a plurality of light guides arranged in a row, and provided for each of the light guides, and with respect to an end face of the light guide A liquid crystal display device having a plurality of LEDs (Light Emitting Diodes) that are light sources that emit light is described. In the liquid crystal display device, a reflection sheet is provided along the light guide plate.

JP 2003-270634 A (published September 25, 2003)

  However, in the structure of the liquid crystal display device described in Patent Document 1, the size of the LED (the size coated with the resin) and the thickness of the light guide plate are approximately the same. A reflecting member (reflector) cannot be provided. Therefore, a resin member and a reflection sheet for fixing the LED are exposed around the LED. The light shielding member or the reflective member only has a function of shielding the light of the LED. The reflection sheet is a member that diffuses and reflects light. That is, the reflection sheet not only reflects light toward the end face direction of the light guide, but also reflects light in all directions. Therefore, in the structure of the liquid crystal display device described in Patent Document 1, light emitted from the LED is not reflected in a desired direction by the resin member or the reflection sheet, but is absorbed on the reflection surface or toward the LED side. In other words, a loss such as the generation of the return light occurs, and the light is not sufficiently incident on the end face of the light guide body, so that a sufficient coupling efficiency cannot be ensured.

  Further, when manufacturing an electronic apparatus such as a lighting device or a liquid crystal display device, it is impossible to reliably avoid the disadvantage that the positional relationship between the LED and the end face of the light guide is shifted (positional shift). However, in the structure of the liquid crystal display device described in Patent Document 1, when the LED is manufactured in a state where the positional relationship between the LED and the end surface of the light guide is deviated, that is, the space between the LED and the end surface of the light guide is between. If the distance is larger than the predetermined distance (tolerance becomes larger), the light from the LED cannot be sufficiently incident on the end face of the light guide, so that the coupling efficiency cannot be maintained in a good state. That is, when the LED and the end face of the light guide body change from a desired positional relationship, there is a problem that the coupling efficiency changes greatly. If the coupling efficiency fluctuates, the intensity of light emitted varies depending on the magnitude of the positional deviation, which causes variations in product characteristics of electronic devices such as lighting devices and liquid crystal display devices.

  In order to solve the above-described problem, a light source module according to the present invention includes a light guide and a light source that causes light to enter at least one end face in a longitudinal direction of the light guide. A specular reflection member is provided at a coupling portion between the light guide and the light guide.

  The regular reflection member may be provided on a side where light is emitted from the light guide in the coupling portion, or provided on a side opposite to the side where light is emitted from the light guide in the coupling portion. It may be provided on both sides.

  An electronic apparatus according to the present invention includes the light source module.

  According to said structure, since the regular reflection member which reflects light regularly is provided in the coupling | bond part of a light source and a light guide, the light radiate | emitted from the light source is toward the end surface direction of a light guide. Can be reflected. Therefore, even if it is manufactured in a state where the positional relationship between the light source and the end face of the light guide is shifted, that is, even if the distance between the light source and the end face of the light guide is greater than a predetermined distance (tolerance increases). Even so, the light from the light source can be sufficiently incident on the end face of the light guide, so that the coupling efficiency can be maintained in a good state. In other words, since the coupling efficiency can be improved, the coupling efficiency does not vary greatly even if the light source and the end face of the light guide vary from a desired positional relationship. Moreover, the intensity | strength of the emitted light from a light guide can be improved.

  According to the configuration of the light source module according to the present invention, even if the distance between the light source and the end surface of the light guide is greater than a predetermined distance (even if the tolerance increases), the light from the light source is transmitted to the end surface of the light guide. Therefore, the coupling efficiency can be maintained in a good state. In other words, since the coupling efficiency can be improved, the coupling efficiency does not vary greatly even if the light source and the end face of the light guide vary from a desired positional relationship. Moreover, various effects that the intensity | strength of the emitted light from a light guide can be improved can be show | played. That is, it is possible to provide a light source module capable of producing the various effects described above and an electronic device including the light source module.

(A), (b) is sectional drawing which shows the structure of the principal part of the light source module which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the structure of the liquid crystal display device provided with the said light source module. It is sectional drawing which shows a part of structure in a liquid crystal display device provided with the said light source module. It is a top view which shows the structure of the light guide in the said light source module. The characteristics of the regular reflection member provided in the light source module will be described, and a front view showing the state of reflected light when visible light is incident on the regular reflection member and the diffuse reflection member at an angle of 45 °. FIG. It is a graph for explaining the effect produced by providing the regular reflection member, and showing the relationship between the distance d and the luminance value of the emitted light. (A), (b) is sectional drawing which shows the structure of the principal part of the light source module which concerns on other embodiment of this invention. It is sectional drawing which shows the structure of the principal part of the light source module which concerns on further another embodiment of this invention. FIG. 10 is a graph for explaining the effect of the present invention in the light source module shown in FIG. 8 and showing the relationship between the distance d and the coupling efficiency.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIG. 2, for example, the liquid crystal display device 1 as an electronic apparatus including the light source module 10 according to the present embodiment has the liquid crystal panel side up, from the bottom (in the Z-axis direction in FIG. 2). Further, the chassis 2, the light source module 10, the liquid crystal panel 3, and the bezel 4 are configured. The light source module 10 includes, in the same order, a reflection sheet 11 as a reflection plate, an LED 12 and an LED substrate 13 as a light source, a light shielding member 14, a light guide 20, a diffusion plate 15, and an optical sheet group 16. The optical sheet group 16 may be provided as necessary, and may not exist in the present invention. Further, the light shielding member 14 is also provided on a side surface portion of the light guide 20 in the longitudinal direction (X-axis direction in FIG. 2) (see FIG. 1B).

  As shown in FIG. 3, the LED 12, the LED substrate 13, and the light shielding member 14 are provided at an end portion of the light guide 20, thereby allowing light from the LED 12 to pass through one end surface ( Incident surface) 21a is incident on the liquid crystal panel 3 through the diffusing plate 15 and the optical sheet group 16 from the exit surface 21d of the light guide 20. Therefore, the light source module 10 according to the present embodiment employs a side edge (also referred to as side light) method.

  By the way, the liquid crystal display device 1 has a problem of blurring of moving images as compared with a CRT (Cathode-Ray Tube) display device. That is, in the CRT display device, since there is a non-light emission period in which the pixel does not emit light between the light emission period of the pixel in a certain frame and the light emission period of the pixel in the next frame, there is little afterimage feeling. On the other hand, since the display method of the liquid crystal display device 1 is a “hold type” that does not have such a non-light emitting period, an afterimage feeling occurs, and this afterimage feeling is recognized by the user as blurring of a moving image.

  Therefore, in the backlight type liquid crystal display device 1, the light source module 10 that is a backlight is divided and sequentially turned off in synchronization with the timing of applying the video signal to the liquid crystal panel 3. Backlight blinking, which is a technique for inserting a black display between them, has been proposed. Thereby, pseudo-impulse type display can be realized, the afterimage feeling can be suppressed, and the power consumption can be reduced.

  The light source module 10 according to the present embodiment has a configuration in which the light guide group 21 is divided by a plurality of light guides 20 as shown in FIG. 4 in order to perform this backlight blinking. These light guides 20 are arranged in parallel in the longitudinal direction. Further, the plurality of light guides 20 are arranged with gaps 22 of about 1 to 2 mm, respectively. Accordingly, in the present embodiment, as shown in FIG. 3, the LED 12 allows light to enter from one end face 21 a in the longitudinal direction of each light guide 20. In addition, it is not necessarily limited to one end surface 21a, but may be incident from the other end surface in the longitudinal direction, and light may be incident from both one end surface 21a and the other end surface. That is, in the present invention, it is sufficient that light is incident from at least one end face. When the light source module is configured not to perform backlight blinking, the light guide group 21 does not have to be divided by a plurality of light guides.

  As shown in FIGS. 1A and 1B, the light source module 10 according to the present embodiment is provided with a film-like regular reflection member 30 at a coupling portion between the LED 12 and the light guide 20. The regular reflection member 30 may be provided on the side where light is emitted from the light guide 20 in the coupling portion (the upper side in FIG. 1 and the liquid crystal panel side in FIG. 2). 20 may be provided on the side opposite to the side from which light is emitted (lower side in FIG. 1, chassis side in FIG. 2), and provided on both sides as shown in FIGS. 1 (a) and 1 (b). May be. More specifically, when the regular reflection member 30 is provided on the side where the light is emitted from the light guide 20 in the coupling portion, the regular reflection member 30 is attached to the surface of the light shielding member 14. ing. In the case where the regular reflection member 30 is provided on the side opposite to the side where light is emitted from the light guide 20 in the coupling portion, the regular reflection member 30 is adhered to the surface of the reflection sheet 11. In addition, the regular reflection member 30 may be extended in places other than the coupling | bond part of LED12 and the light guide 20. FIG.

  The regular reflection member in the present invention refers to a member having a reflection characteristic (so-called mirror surface function) that mainly reflects light mainly. More specifically, the reflectance of visible light is 75% or more, and the reflection component is It refers to a member that is substantially regular reflection (substantially only regular reflection). On the other hand, the diffuse reflection member refers to a member having a reflection characteristic for diffusing and reflecting light. More specifically, the reflectance of visible light is 75% or more, and the reflection component is substantially diffuse reflection ( It refers to a member that performs substantially only diffuse reflection. The state of reflected light when visible light (incident light) is incident on the specular reflection member and diffuse reflection member at an angle (incident angle) of 45 °, that is, the reflection characteristics of the regular reflection member and diffuse reflection member, As shown in FIG. As is apparent from FIG. 5, in the regular reflection member, the regular reflection component (shown by the shade in the figure) is concentrated at an angle (reflection angle) of 45 °, and the reflection component is almost regular reflection. On the other hand, in the diffuse reflection member, a diffuse component (represented by hatching in the figure) is recognized at a wide angle around the angle 0 ° (perpendicular to the surface of the diffuse reflection member), and the reflection component is almost diffused. It turns out that it is a reflection. That is, it can be seen that the regular reflection member has a characteristic that the reflectance of visible light is 75% or more and the reflection component is substantially regular reflection (substantially performs regular reflection only).

  Here, as the regular reflection member, it is more desirable to use a member having a high visible light reflectance. Specifically, as the regular reflection member, for example, an ESR / D-ESR sheet manufactured by Sumitomo 3M, a reflex white sheet manufactured by Kimoto, a member having a highly reflective surface by metal deposition, and a metal mirror-finished surface are used. The member provided, the member provided with the mirror processing surface, etc. can be mentioned.

  The material of the regular reflection member 30 is not particularly limited as long as it has the above-described characteristics. Further, the size of the regular reflection member 30 may be appropriately set according to the size of the light source module 10. Furthermore, the thickness of the regular reflection member 30 is preferably thinner as long as the above characteristics are not impaired, and can be formed into a film of, for example, 0.1 mm or less.

  The effect produced by providing the regular reflection member 30 at the joint between the LED 12 and the light guide 20 will be described below with reference to FIG. 6 shows a distance d (see FIG. 1A) from the top of the LED 12 as the light source to the end face (incident surface) of the light guide 20 in the light source module 10 shown in FIG. 1, and the luminance of the emitted light. It is a graph which shows and shows the relationship with a value.

The luminance value is generally a value representing the brightness of a display unit such as a display. Specifically, the luminance value indicates the luminous intensity per unit area of light emitted from the light source, and the unit is cd / m ^2. It is. The luminance value can be measured using a luminance meter. The luminance values shown in FIG. 6 are measured using a two-dimensional luminance meter “CA-2000” manufactured by Konica Minolta. The luminance value in the present invention is the vertical luminance value of the light (emitted light) emitted from the emission surface 21d that is 200 mm away from the end face (incident surface) of the light guide 20 and is directly above the light guide 20 (on the light emitting surface). It is a value measured using the two-dimensional luminance meter from the vertical direction.

  When the regular reflection member 30 is not provided at the coupling portion between the LED 12 and the light guide 20 (prior art, represented by a rhombus in the graph), the luminance value of the emitted light significantly decreases as the distance d increases. On the other hand, when the regular reflection member 30 is provided on the side opposite to the side from which light is emitted from the light guide 20 in the coupling portion (described as “below” in the graph) (indicated by a triangle in the graph). Since the light emitted from the LED 12 can be reflected toward the end face direction of the light guide 20, the ratio of the luminance value of the emitted light that decreases as the distance d increases can be reduced. In addition, when the regular reflection member 30 is provided (represented by a square in the graph) on the side where light is emitted from the light guide 20 in the coupling portion (described as “upper” in the graph), the distance d increases. Accordingly, it is possible to further reduce the ratio of the luminance value of the emitted light that decreases according to this. When the regular reflection members 30 are provided on both sides of the coupling portion (represented by a cross in the graph), the ratio of the luminance value of the emitted light that decreases as the distance d increases can be minimized.

  More specifically, when the regular reflection member 30 is not provided at the coupling portion, the luminance value of the emitted light is significantly reduced by 0.79 times as the distance d increases from 0.5 mm to 2.0 mm (21) %). Since the luminance value of the emitted light is substantially proportional to the coupling efficiency, the coupling efficiency varies greatly with respect to the variation of the distance d. On the other hand, when the regular reflection members 30 are provided on both sides of the coupling portion, the luminance value of the emitted light decreases 0.93 times even if the distance d increases from 0.5 mm to 2.0 mm. Stay (retain 7% reduction). That is, the coupling efficiency does not vary greatly. Therefore, when the distance d, which is the case where the light guide 20 is at the reference position, is 0.5 mm, the regular reflection members 30 are provided on both sides of the coupling portion, so that the regular reflection member 30 is not provided. Thus, it can be seen that the luminance value of the emitted light, that is, the coupling efficiency is increased 1.14 times (as much as 14%). Further, when the distance d is 2.0 mm, by providing the regular reflection members 30 on both sides of the coupling portion, compared to the case where the regular reflection member 30 is not provided in the coupling portion, the luminance value of the emitted light, that is, It can be seen that the coupling efficiency is greatly increased by 1.34 times (an increase of 34%). Therefore, it can be seen that as the distance d is increased, the coupling efficiency is more significantly improved, and the effect of providing the regular reflection member 30 is further increased. That is, since the coupling efficiency does not fluctuate greatly, variations in the optical characteristics of the light source module 10 can be suppressed.

  In addition, when the regular reflection member 30 is provided on the side where the light is emitted from the light guide 20, the regular reflection member 30 is provided on the side opposite to the side where the light is emitted from the light guide 20. Thus, the rate of decrease in the luminance value is smaller due to the difference between the side where the regular reflection member 30 is not provided is the reflection sheet 11 or the light shielding member 14.

  As described above, the light source module 10 according to the present embodiment includes the light guide 20 and the LED 12 that causes light to enter at least one end face 21a in the longitudinal direction of the light guide 20. More specifically, the light source module 10 according to the present embodiment includes a plurality of light guides 20 provided with gaps 22 in parallel with each other in the longitudinal direction, and the longitudinal direction of each light guide 20. A plurality of LEDs 12 that allow light to enter from at least one end face 21a, and a plurality of optical path conversion units (not shown) provided to extract the light guided inside each light guide 20. I have. The optical path changing unit is provided on the side where the light is emitted from the light guide 20 or on the side of the reflection sheet 11 which is the opposite side.

  In the light source module 10, a regular reflection member 30 is provided at a coupling portion between the LED 12 and the light guide 20. According to said structure, since the regular reflection member 30 which reflects light regularly is provided in the said coupling | bond part, the light radiate | emitted from LED12 can be reflected toward the end surface direction of the light guide 20. it can. Therefore, even if the LED 12 and the end surface of the light guide 20 are manufactured in a shifted state, that is, the LED 12 and the end surface of the light guide 20 are separated from each other by a predetermined distance (tolerance is Since the light from the LED 12 can be sufficiently incident on the end face of the light guide 20, the coupling efficiency can be maintained in a good state. In other words, since the coupling efficiency can be improved, the coupling efficiency does not vary greatly even if the LED 12 and the end face of the light guide 20 vary from the desired positional relationship. Moreover, various effects that the intensity | strength of the emitted light from the light guide 20 can be improved can be show | played. That is, it is possible to provide a light source module that can achieve the various effects described above.

  Further, for example, a liquid crystal display device 1 as an electronic apparatus according to the present invention has a configuration including the light source module 10. According to said structure, the electronic device which can show | play the said various effects can be provided. Examples of the electronic device include a lighting device and a backlight in addition to the liquid crystal display device.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Instead of sticking the regular reflection member 30 to the surface of the light shielding member 14 or the surface of the reflection sheet 11, as shown in FIGS. 7A and 7B, the light source module 10 according to the present embodiment includes an LED 12. The specular reflection member 30 is provided on the surface of the aperture (light guide holding member) 31 at the coupling portion between the light guide 20 and the light guide 20. More specifically, the regular reflection member 30 of the light source module 10 according to the present embodiment has a surface near the LED 12 in the aperture 31 that holds the light guide 20, that is, the LED 12 and the light guide 20 in the aperture 31. It is affixed to the surface of the location located in the joint part. In the present embodiment, the regular reflection member 30 may be provided on the side of the aperture 31 where light is emitted from the light guide 20, and is provided on the side opposite to the side where light is emitted from the light guide 20. It may be provided, and may be provided on both sides. Further, the regular reflection member 30 may be attached to the entire surface of the portion of the aperture 31 located at the coupling portion between the LED 12 and the light guide 20 so as to surround the light guide 20.

  Even in the above-described configuration, similarly to the first embodiment, even if the positional relationship between the LED 12 and the end face of the light guide 20 is shifted, that is, between the LED 12 and the end face of the light guide 20. Can be sufficiently incident on the end face of the light guide 20 even when the distance is larger than a predetermined distance (even if the tolerance is increased), so that the coupling efficiency can be maintained in a good state. it can. In other words, since the coupling efficiency can be improved, the coupling efficiency does not vary greatly even if the LED 12 and the end face of the light guide 20 vary from the desired positional relationship. Moreover, various effects that the intensity | strength of the emitted light from the light guide 20 can be improved can be show | played. That is, it is possible to provide a light source module that can achieve the various effects described above.

  Moreover, according to said structure, the electronic device which can show | play the said various effects can be provided.

  In the light source module 10 according to the first and second embodiments, the regular reflection member 30 is attached to the surface of the light shielding member 14, the surface of the reflection sheet 11, or the surface of the aperture 31. However, instead of sticking the regular reflection member 30, the visible light reflectivity is 75% or more on peripheral members (members around the LED 12) such as the light shielding member 14, the reflection sheet 11, and the aperture 31, and the like. A function as a regular reflection member can be imparted to the peripheral member by attaching a substance having a characteristic that the component is substantially regular reflection (substantially only regular reflection) by vapor deposition or the like.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIGS. For convenience of explanation, members having the same functions as those described in the first and second embodiments are given the same reference numerals and explanation thereof is omitted.

  Instead of adhering the regular reflection member 30 to the surface of the light shielding member 14, the surface of the reflection sheet 11, or the surface of the aperture 31, the light source module according to the present embodiment includes a substance constituting the reflection sheet and the light shielding member, It is the structure replaced with the substance which comprises a regular reflection member. More specifically, as shown in FIG. 8, the reflection sheet 11a and the light shielding member 14a of the light source module 10a according to the present embodiment have a visible light reflectance of 75% or more, and the reflection component is substantially regular reflection. It is comprised with the substance provided with the characteristic which becomes (it performs only specular reflection substantially), and is provided with the function as a regular reflection member mentioned above. Here, as the regular reflection member, it is more desirable to use a member having a high visible light reflectance. Specifically, as the regular reflection member, for example, an ESR / D-ESR sheet manufactured by Sumitomo 3M, a reflex white sheet manufactured by Kimoto, a member having a highly reflective surface by metal deposition, and a metal mirror-finished surface are used. The member provided, the member provided with the mirror processing surface, etc. can be mentioned.

  The effect produced by the reflection sheet 11a and the light shielding member 14a having a function as a regular reflection member will be described below with reference to FIG. FIG. 8 shows an actual measurement of the relationship between the coupling efficiency and the distance d (see FIG. 1A) from the top of the LED 12 to the end face (incident surface) of the light guide 20 in the light source module 10a shown in FIG. It is a graph shown.

  When the reflection sheet and the light-shielding member do not have a function as a regular reflection member, that is, when the reflection sheet and the light-shielding member are made of a material having a reflection characteristic that diffusely reflects light (reflectance 90%) (conventional) In technology and graphs, the coupling efficiency decreases significantly as the distance d increases. On the other hand, when the reflection sheet and the light shielding member are made of a material having a reflection characteristic that regularly reflects light (reflectance 90%), that is, the reflection sheet 11a and the light shielding member 14a function as regular reflection members. (Represented by a square in the graph), the light emitted from the LED 12 can be reflected toward the end face direction of the light guide 20, so that the coupling efficiency decreases as the distance d increases. The ratio can be reduced.

  Therefore, also in the above configuration, as in the first and second embodiments, even if the positional relationship between the LED 12 and the end face of the light guide 20 is shifted, that is, the LED 12 and the light guide 20 are manufactured. Even if the distance from the end surface of the light source is larger than a predetermined distance (even if the tolerance is increased), the light from the LED 12 can be sufficiently incident on the end surface of the light guide 20, so that the coupling efficiency is good. Can be maintained. In other words, since the coupling efficiency can be improved, the coupling efficiency does not vary greatly even if the LED 12 and the end face of the light guide 20 vary from the desired positional relationship. Moreover, various effects that the intensity | strength of the emitted light from the light guide 20 can be improved can be show | played. That is, it is possible to provide a light source module that can achieve the various effects described above.

  Moreover, according to said structure, the electronic device which can show | play the said various effects can be provided.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention relates to a light source used in a backlight including a side edge (also referred to as a sidelight) type light guide plate that emits light from a light source in a planar shape by a light guide in order to reduce the thickness of the liquid crystal display device, for example. The present invention can be suitably used for a module and an electronic device including the module.

1 Liquid crystal display device (electronic equipment)
3 Liquid crystal panel 10 Light source module 10a Light source module 11 Reflective sheet 11a Reflective sheet 12 LED (light source)
14 light shielding member 14a light shielding member 15 diffuser plate 20 light guide 21 light guide group 21a end face 30 regular reflection member 31 aperture

Claims (4)

In a light source module comprising a light guide and a light source that makes light incident on at least one end face in the longitudinal direction of the light guide,
A light source module, wherein a regular reflection member is provided at a coupling portion between the light source and the light guide.   The light source module according to claim 1, wherein a regular reflection member is provided on a side where light is emitted from the light guide in the coupling portion.   The light source module according to claim 1, wherein a regular reflection member is provided on a side opposite to a side where light is emitted from the light guide in the coupling portion.   An electronic apparatus comprising the light source module according to any one of claims 1 to 3.

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