JP2008251432A - Lighting system and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system free from generation of luminance unevenness or a lamp image. <P>SOLUTION: The lighting system (11) is provided with an optical sheet (22), and a cylindrical light source (20) or a plurality of them (20) arrayed in parallel arranged at a given interval with the optical sheet (22). The lighting system (11) is also provided with a first thread (26) made of a translucent material and put up in a first direction parallel with the cylindrical light source(s) (20) so as to be in or nearly in contact with the optical sheet (22), and a second thread (27) made of a translucent material and put up in a second direction crossing the first direction so as to cross the first thread. At a crossing point of the first thread (26) and the second thread (27), the first one (26) is located toward an optical sheet side while the second (27) is located at a cylindrical light source side, so that the both threads (26), (27) prevent the optical sheet (22) from bending toward the cylindrical light source side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lighting device, and more particularly to a lighting device used as a backlight device of a liquid crystal display device. The present invention also relates to a liquid crystal display device including such an illumination device.

  A liquid crystal panel used as a display device for a personal computer or a television does not emit light. Therefore, in order to display an image on a display device including a liquid crystal panel, an illumination device such as a backlight device that illuminates the liquid crystal panel from behind is required.

  Backlight devices are classified into an edge light system and a direct system according to a method for obtaining planar light projected on a liquid crystal panel. In the edge light method, a light source is disposed along the end face of a light guide plate arranged behind the liquid crystal panel, and light emitted from the light source is incident on the light guide plate from the end face and diffused, and the diffused light is diffused. The light is projected from the light guide plate to the liquid crystal panel. In the direct method, an optical sheet such as a diffusion plate is arranged behind the liquid crystal panel and a plurality of cylindrical light sources are arranged behind the optical sheet, and light emitted from the cylindrical light source is incident on the optical sheet from its main surface. The diffused light is projected from the optical sheet onto the liquid crystal panel. Whether the edge light method or the direct light method is adopted is determined according to the performance required for the liquid crystal display device, but the direct light method has higher light use efficiency than the edge light method. For display devices that require this, an edge light type backlight device is used rather than a direct type.

  The conventional direct-type backlight device has a space between the optical sheet and the cylindrical light source, and one of the plurality of optical sheets is a diffusion plate made of a relatively thick and rigid acrylic plate, etc. On this, another optical sheet having a relatively small thickness was placed. If the thickness of the diffusion plate is reduced or eliminated in order to reduce the cost, the optical sheet will bend in the direction in which the optical sheet and the cylindrical light source face each other, and the deflection is a surface emission emitted from the optical sheet to the liquid crystal panel. There was a problem that the uniformity of the film was significantly impaired. In particular, in recent years, full high-definition or full high-definition televisions with an aspect ratio of 16: 9 are becoming widespread, which is longer than conventional televisions with an aspect ratio of 4: 3. For this reason, the optical sheet is further bent, and an image of a cylindrical light source (so-called lamp image) arranged at an interval appears on the light emitting surface, which may further impair surface light emission non-uniformity.

  Patent Documents 1 and 2 disclose a backlight device having a mechanism capable of preventing such bending of an optical sheet. The backlight device of Patent Document 1 has a net disposed behind the optical sheet. Usually, since the net is stretched without slack, it is possible to prevent the optical sheet from bending toward the cylindrical light source. However, since the net covers the entire surface of the optical sheet and warps and wefts are alternately arranged up and down as will be described later, there is a problem that the loss of the amount of light incident on the liquid crystal panel is extremely large.

In the backlight device of Patent Document 2, a transparent weft is stretched behind the optical sheet, and the warp prevents the optical sheet from being bent. However, even if it is possible to reduce the deflection of the optical sheet with only the weft with a small screen size of 22 type or less, the large-sized liquid crystal display devices provided in recent years can prevent the deflection of the optical sheet with only the weft. I can't.
WO2005 / 116518 JP 2003-203503 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a direct-type illumination device that can effectively prevent the bending of an optical sheet and a liquid crystal display device using the illumination device.

  The illumination device of the present invention that achieves this object is a direct illumination type illumination device, and when a yarn is arranged behind the optical sheet, a yarn (parallel yarn) arranged parallel to the cylindrical light source and a direction orthogonal to the cylindrical light source The yarns (orthogonal yarns) arranged in (1) are based on the knowledge that they have different effects on the surface emission transmitted through the optical sheet.

  Specifically, as shown in FIG. 1, when the parallel thread 26 is arranged behind the optical sheet 22 in parallel with the cylindrical light source 20, if the parallel thread 26 is in contact with the optical sheet group 14, The shadow of the parallel thread 26 does not occur behind (on the optical sheet side). However, when the parallel thread 26 is separated from the optical sheet 22, a shadow 100 is generated behind the parallel thread 26, and the shadow 100 impairs the uniformity of light incident on the liquid crystal panel. On the other hand, when the orthogonal thread 27 orthogonal to the cylindrical light source 20 is arranged behind the optical sheet group 14, the orthogonal thread 27 has a slight shadow behind the orthogonal thread 27 when contacting the optical sheet group 14. However, the shadow disappears as the distance from the optical sheet group 14 increases. Therefore, when the optical sheet 22 is supported by the parallel thread 26 parallel to the cylindrical light source 20 and the orthogonal thread 27 orthogonal thereto, the parallel thread 26 and the orthogonal thread 27 are always located where the parallel thread 26 intersects or entangles. It is preferable that the orthogonal thread 27 is positioned on the cylindrical light source side while being positioned on the optical sheet side.

  Based on this knowledge, in the present invention, the illumination device (11) is arranged in parallel with the optical sheet (22) and the optical sheet (22) and at a predetermined interval from the optical sheet (22). A single cylindrical light source (20) or a plurality of cylindrical light sources (20) arranged in parallel, and the light emitted from the cylindrical light source (20) is output via the optical sheet (22) In the device and the liquid crystal display device, the illuminating device (11) is made of a light-transmitting material, and is in contact with or substantially in contact with the optical sheet (22) in a first direction parallel to the cylindrical light source (20). The first thread (26) stretched so as to be in contact with the first thread (26) and made of a light-transmitting material, and stretched so as to intersect the first thread in a second direction orthogonal to the first direction. A second thread (27) provided, the first thread (26) and At the intersection of the two threads (27), the first thread (26) is located on the optical sheet side and the second thread (27) is located on the cylindrical light source side. The yarn (26) and the second yarn (27) prevent the optical sheet (22) from being bent toward the cylindrical light source.

  In the second embodiment of the illumination device and the liquid crystal display device according to the present invention, the illumination device includes a rectangular bottom portion (16), and an upper frame (171) and a lower frame arranged along the edge of the bottom portion (16). (172) A box-shaped housing (15) having a quadrangular frame portion including a left frame (173) and a right frame (174), and an opening (18) of the housing (15) are covered. The arranged optical sheet (22) and one or more cylinders arranged between the optical sheet (22) and the bottom (16) and extending in parallel with the upper frame (171) and the lower frame (172) It has a light source (20). In this illuminating device, the optical sheet (22) is bent between the frame portion (17) and the optical sheet (22) and supports the optical sheet (22) toward the cylindrical light source (20). It has a support member (25) which prevents this. The support member (25) has both ends supported by the left frame (173), a pair of weft portions (531, 532) extending from the left frame (173) toward the right frame (174), Both ends are supported by the left side thread (53) having the warp part (533) that connects the pair of weft parts (531, 532) and the right frame (174), and the left frame from the right frame (174). A pair of weft portions (541, 542) extending toward (173), a right yarn (54) having a warp portion (543) connecting the pair of weft portions (541, 542), and the upper frame (171). Both ends are supported by a pair of warp portions (511, 512) extending from the upper frame (171) toward the lower frame (172) and a weft portion connecting the pair of warp portions (511, 512). An upper thread (51) having (513); Both ends are supported by the lower frame (172), a pair of warp portions (521, 522) extending from the lower frame (172) toward the upper frame (171), and the pair of warp portions (521, 522) and a lower yarn (52) having a weft portion (523) connecting the upper yarn (51), the warp portion (511, 512) and the left and right bent portions of the weft portion (513) The left yarn (53) and the right yarn (54) are intertwined with the bent portion of one weft portion (531, 541) and the warp yarn portion (533, 543), and the warp yarn portion (521) in the lower yarn (52) , 522) and the left and right bent portions of the weft portion (523) are the bent portions of the other weft portion (532, 542) and the warp portion (533, 543) of the left yarn (53) and the right yarn (54). Intertwined, the warp part (511, 12, 521, 522, 533, 543) and the weft portion (513, 531, 541, 532, 542, 523) are located on the optical sheet side, and the warp portion is located on the cylindrical light source. It is located on the side.

  According to the illuminating device and the liquid crystal display device configured as described above, the optical sheet is supported by the thread parallel to the cylindrical light source and the thread orthogonal thereto, so that the optical sheet is not bent toward the cylindrical light source. The distance between the sheet and the cylindrical light source is always kept constant. As a result, it is possible to provide uniform surface light emission to the liquid crystal panel without causing uneven brightness and a lamp image caused by the distance between the optical sheet and the cylindrical light source being different depending on the location.

  In particular, in the present invention, a thread parallel to the cylindrical light source is disposed on the optical sheet side, a thread orthogonal thereto is disposed on the cylindrical light source side, and the gap between the former thread and the optical sheet is eliminated. There is no shadow behind the yarn, and uniform surface emission is ensured.

  Embodiments of a lighting device and a liquid crystal display device according to the present invention will be described below with reference to the accompanying drawings.

Embodiment 1

  FIG. 2 shows a lighting device according to the present invention and a liquid crystal display device including the lighting device. As shown in the figure, the liquid crystal display device 10 includes a backlight device 11 that is a lighting device and a liquid crystal panel 12.

  The backlight device 11 includes a light source unit 13 and an optical sheet group 14. The light source unit 13 has a box-shaped housing 15. In the embodiment, the housing 15 has a bottom portion 16 having a horizontally long rectangle, and four frame portions 17-an upper frame 171, a lower frame 172, a left frame 173, and a right frame 174-extending along four sides of the bottom portion 16. In addition, a rectangular opening 18 is formed inside these four frame portions 17. In a preferred embodiment, the inner surface of the bottom 16 and the inner surface of the frame 17 are covered with a reflective material having a high reflectivity. It is preferable to use a reflective sheet 19 having a high reflectance as the reflective material. Further, as shown in the drawing, the inner surfaces of the four frames 17 are preferably inclined outward from the bottom 16 toward the opening 18.

  A plurality of cylindrical light sources 20 are arranged inside the housing 15. The cylindrical light source 20 is a cold cathode tube or a hot cathode tube. In the embodiment, eight cylindrical light sources 20 are arranged in the horizontal direction with a certain interval in the vertical direction. Each cylindrical light source 20 is supported by light source support portions 21 provided on the left and right frames 17 with a predetermined interval (for example, about 1 to 2 mm) between the cylindrical light source 20 and the bottom portion 16.

  On the housing 15, the optical sheet group 14 and the liquid crystal panel 12 are arranged so as to cover the housing opening 18. The liquid crystal panel 12 is a known liquid crystal panel. The optical sheet group 14 includes one optical sheet or a plurality of stacked optical sheets. In the embodiment, the optical sheet group 14 includes three optical sheets, a milky white diffusion sheet 22, a first light collecting sheet 23, and a second light collecting sheet 24 in order from the light source unit 13. In particular, in the conventional backlight device, a rigid and high-rigidity plastic sheet having a considerable thickness (for example, 1 to 2 mm) and having no flexibility is adopted as the diffusion sheet. Then, a flexible sheet having a small thickness (for example, 1 mm or less) and flexibility is used for the diffusion sheet 22. As with the diffusion sheet 22, the first and second light collecting sheets 23 and 24 are also made of a flexible sheet such as a thin and flexible lens sheet.

  The housing opening 18 is provided with a support member 25 in order to prevent the diffusion sheet 22 and the light collecting sheets 23 and 24 made of a flexible sheet from being bent toward the cylindrical light source 20 as described above. The support members 25 are parallel yarns (first yarns) 26 that are wefts extending in the transverse direction (first direction) in parallel with the cylindrical light source 20 and longitudinal directions (second direction) orthogonal to the cylindrical light source 20. An orthogonal yarn (second yarn) 27, which is a warp yarn that extends, is included. In the embodiment, two parallel yarns 26 and two orthogonal yarns 27 are provided, but the number of each yarn is not limited.

  As shown in the figure, the parallel yarn 26 is preferably arranged along a line obtained by projecting the cylindrical light source 20 perpendicularly to the optical sheet group 14. In the embodiment, two parallel yarns 26 are respectively disposed right above the two central cylindrical light sources 20. Further, the locations and the number of the parallel yarns 26 and the orthogonal yarns 27 are set to the most preferable state in order to prevent the optical sheet group 14 from being bent toward the cylindrical light source 20. For example, the gap may be short near the center of the opening 18 and the gap between the yarns may be increased toward the outside. In addition, as shown in FIG. 8, when two parallel yarns 26 and two orthogonal yarns 27 are provided, these parallel yarns 26 are arranged at positions that divide the opening 18 into approximately three equal parts in the longitudinal direction. It is preferable to arrange the opening 18 at a position that divides the opening 18 into approximately three equal parts.

  The parallel yarn 26 and the orthogonal yarn 27 are preferably formed of a colorless transparent or white material. This is because the colored yarn absorbs light emitted from the cylindrical light source 20 and causes a shadow behind the yarn. Moreover, it is preferable that the parallel yarn 26 and the orthogonal yarn 27 are not a twisted yarn obtained by twisting a plurality of yarns but a single yarn (monofilament) such as a fishing line or an optical fiber. This is because the twisted yarn reflects light on the twisted portion of the yarn and causes a shadow behind the yarn.

  The parallel yarn 26 and the orthogonal yarn 27 desirably satisfy various requirements in order to prevent the optical sheet group 14 from being bent. Specifically, when the yarns 26 and 27 are easily stretched when receiving a force from the optical sheet group 14, a sufficient deflection preventing effect cannot be obtained. Further, it is necessary to apply a necessary tension to the yarns 26 and 27 in order to prevent the optical sheet group 14 from being bent, and the yarns 26 and 27 should not be cut or plastically deformed by the tension. Furthermore, the temperature in the housing 15 reaches about 40 ° C. due to the heat generated by the cylindrical light source 20, and the yarns 26 and 27 should not be plastically deformed (deformation caused by viscous flow) due to the heat. In particular, the yarn of organic material is easily deformed (flowed) by heat. From the above circumstances, the yarns 26 and 27 preferably have a low elongation, a high tensile strength, and a high glass transition temperature. Specifically, the yarns 26 and 27 are preferably made of organic fibers such as nylon, polyethylene, polyester, or glass fibers. In particular, polyester fiber is a particularly preferable material because it is excellent in operability when the end portion is tied and fixed to a fixture, and glass fiber is excellent in tensile strength as compared with other materials. The cross-sectional shape of the threads 26 and 27 is preferably a circular cross section in which the contact state with the sheet is constant.

  As the diameter of the parallel yarn 26 and the orthogonal yarn 27 increases, the elongation decreases and the tensile strength increases. However, as the yarn diameter increases, the possibility of shadowing behind increases. Considering these points, the diameters of the threads 26 and 27 are preferably about 0.15 mm to 0.4 mm. The parallel yarn 26 and the orthogonal yarn 27 may have the same diameter. However, as described above, in order to separate the orthogonal yarn 27 from the optical sheet group 14 as much as possible, the parallel yarn 26 is thicker than the orthogonal yarn 27. For example, it is preferable to have a diameter of about 0.25 mm or more. Accordingly, the diameter of the parallel yarn 26 is about 0.15 mm to 0.4 mm, preferably about 0.25 mm to 0.4 mm, and the orthogonal yarn 27 is about 0.15 mm to 0.4 mm.

  The tension applied to the parallel yarns 26 and the orthogonal yarns 27 varies depending on the size of the opening 18. For example, when a polyester organic fiber yarn is used in a 32-inch backlight device, a short side is 40 N or more. It is preferable to apply a tension of 25 N or more in the side direction.

  The parallel yarn 26 and the orthogonal yarn 27 arranged in the housing opening 18 are exposed to ultraviolet rays contained in the light emitted from the cylindrical light source 20. Therefore, it is preferable to use the yarns 26 and 27 that contain an ultraviolet absorber inside, or those that have a surface coated with the ultraviolet absorber.

  As described above, the parallel yarn 26 and the orthogonal yarn 27 must be held with a desired tension applied. Therefore, both ends of the threads 26 and 27 need to be securely fixed to the housing 15. The method for fixing the yarn is not limited to a specific method, but the following fixing methods can be suitably used.

  FIG. 4 shows an example of fixing the threads 26 and 27. In this fixing method, a groove 28 having a depth substantially the same as the diameter of the threads 26 and 27 is formed in the frame 17, the ends of the threads 26 and 27 are positioned in the groove 28, and an appropriate adhesive (not shown) is formed. ) To fix the threads 26 and 27. Even when other fixing methods described below are adopted, a groove 28 is formed and the threads 26 and 27 are formed there in order to closely adhere the diffusion sheet 22 supported on the upper surface of the frame 17 to the frame 17 without a gap. Is preferably accommodated.

  As shown in FIG. 5, the threads 26 and 27 may be connected to and fixed to a fixing portion 30 provided on the back surface 29 of the housing 15. Various types of fixing portions 30 are shown in FIG. FIG. 6A shows a form in which the screw 31 attached to the housing back surface 29 is used as the fixing portion 30 and the ends of the threads 26 and 27 are connected to the screw 31. The screw 31 does not need to be specially provided to fix the threads 26 and 27. For example, when there is a spacer pin disposed in the housing 15 to prevent the diffusion sheet 22 or the like from being bent, this spacer It may be a screw for fixing the pin. Further, when the screw 31 has a lamp holder for holding the plurality of cylindrical light sources 20 at a predetermined interval, the screw 31 may be a screw for fixing the lamp holder.

  FIG. 6B shows a form in which the inverted L-shaped protrusion 32 provided on the housing back surface 29 is used as the fixing portion 30. In this case, the threads 26 and 27 are connected by being wound around the protrusion 32 and tied.

  FIG. 6C shows a form in which the plate-like protrusion 33 provided on the housing back surface 29 is used as the fixing portion 30. In this case, a hole 34 is formed in the protruding portion 33, and threads 26 and 27 are tied and connected to a rod 35 provided behind the protruding portion 33.

  FIG. 6D shows a form in which a plate-like protrusion 36 provided on the housing back surface 29 is used as the fixing part 30. In this case, the threads 26 and 27 are wound around the protrusion 36 and fixed with an adhesive (not shown).

  6 (e) and 6 (f) show a case where a hollow fiber made of a transparent glass material that cannot be tied like a yarn made of a synthetic resin, or an optical fiber without an outer coating layer is used for the yarns 26 and 27. An effective fixing method is shown. Specifically, FIG. 6E shows a method of welding and fixing the ends of the fiber yarns 26 and 27 to a metal projection 37 fixed to the rear surface 29 of the housing, and FIG. A method of hooking and fixing a ring 38, on which the fiber yarn is welded and fixed to the ends of 26 and 27, to a protrusion 39 is shown.

  Whichever method is employed, it is preferable that the ends of the threads 26 and 27 are securely fixed to the protrusions with an adhesive (not shown).

  Further, in order to ensure a constant tension on the threads 26 and 27, a spring such as a coil spring 40 may be connected to the ends of the threads 26 and 27 as shown in FIG.

  According to the backlight device 11 and the liquid crystal display device 10 configured as described above, the backlight device 11 and the liquid crystal display device 10 are not limited to the case where the backlight device 11 and the liquid crystal display device 10 are installed vertically. Even when the liquid crystal panel 12 is installed obliquely or upward, the flexible diffusion sheet 22 and the optical sheet group 14 including the flexible diffusion sheet 22 are supported by the parallel thread 26 and the orthogonal thread 27 toward the cylindrical light source 20. Without being bent, the distance between the diffusion sheet 22 and the optical sheet group 14 including the diffusion sheet 22 and the plurality of cylindrical light sources 20 is always kept constant. As a result, luminance unevenness and a lamp image caused by the distance between the diffusing sheet 22 and the optical sheet group 14 including the diffusing sheet 22 and the plurality of cylindrical light sources 20 being different depending on places are not generated, and the liquid crystal panel 12 is uniform. Surface emission can be provided.

  In particular, in the present invention, the parallel thread 26 is disposed on the optical sheet group side, the orthogonal thread 27 is disposed on the cylindrical light source side, and the gap between the parallel thread 26 and the optical sheet group 14 is eliminated. , 27, no shadow is produced, and uniform surface light emission is ensured. Further, since the yarns 26 and 27 are not a twisted yarn but a single yarn (monofilament) such as a fishing line or an optical fiber is used, there is no shadow caused by twisting of the yarn when the twisted yarn is used. .

  In the first embodiment described above, the parallel yarn 26 and the orthogonal yarn 27 intersect with the parallel yarn 26 positioned on the upper side (optical sheet side) and the orthogonal yarn 27 positioned on the lower side (cylindrical light source side). . However, as shown in FIG. 9, the parallel yarn 26 may be rotated around the orthogonal yarn 27 once or a plurality of times at the intersection 41 of the parallel yarn 26 and the orthogonal yarn 27. In this case, the relative movement of the two yarns 26 and 27 is prevented by the mutual holding of the parallel yarn 26 and the orthogonal yarn 27. In particular, when two parallel yarns 26 and two orthogonal yarns 27 are provided as shown in FIG. 8, the parallel yarns 26 circulate around the orthogonal yarns 27 at the intersections of these yarns 26, 27. Since the force received by the parallel yarn 26 and the orthogonal yarn 27 from the optical sheet group 14 can be distributed to the other yarns 27 and 26, the support strength of the quadrangular region surrounded by the four intersecting portions 41 is increased, and the optical system is more stable. The sheet group 14 can be supported.

Embodiment 2

  FIG. 10 shows the light source unit 13 ′ of the backlight device and the liquid crystal display device according to the second embodiment. The light source unit 13 ′ of this embodiment is characterized in that each of a plurality of yarns has a composite yarn function and an orthogonal yarn function described above. More specifically, the support member that supports the optical sheet group includes four threads 51, 52, 53, and 54. Each yarn is composed of a single yarn (monofilament) having translucency as in the first embodiment.

  More specifically, the left side thread 53 arranged on the left side of the figure has both ends fixed to the left side of the housing 15 and a pair of weft parts 531 extending from the left frame 173 toward the right frame 174, 532 and a warp portion 533 that connects the right end portions of the weft portions 531 and 532. Similarly, the right thread 54 arranged on the right side of the figure has both ends fixed to the right side of the housing 15, and a pair of weft portions 541, 542 extending from the right frame 174 toward the left frame 173, and the weft It consists of the warp part 543 which connects the right end part of the parts 541 and 542. Further, the upper thread 51 disposed on the upper side of the figure has both ends fixed to the upper side of the housing 15, and a pair of warp portions 511, 512 extending from the upper frame 171 toward the lower frame 172, and the warp portion The lower end portions of 511 and 512 are composed of a weft portion 513. Similarly, a lower thread 52 disposed on the lower side of the figure has both ends fixed to the lower side of the casing 15 and a pair of warp portions 521 and 522 extending from the lower frame 172 toward the upper frame 171. And the weft portion 523 that connects the upper end portions of the warp portions 521 and 522.

  As shown in FIG. 10B, the left and right bent portions of the warp yarn portions 511 and 512 and the weft yarn portion 513 in the upper yarn 51 are the upper weft yarn portions 531 and 541 and the warp yarn portion 533 in the left yarn 53 and the right yarn 54, respectively. The weft yarns 531, 541 and 513 are located on the optical sheet side, and the warp yarns 511, 512, 533 and 543 are located on the cylindrical light source side. Similarly, the left and right bent portions of the warp yarn portions 521 and 522 and the weft yarn portion 523 in the lower yarn 52 are the lower weft yarn portions 532 and 542 and the bent portions of the warp yarn portions 533 and 543 in the left yarn 53 and the right yarn 54, respectively. The weft portions 532, 542, and 523 are located on the optical sheet side, and the warp portions 521, 522, 533, and 543 are located on the cylindrical light source side.

  As described above, in the backlight device 11 of the second embodiment, parallel yarns that are parallel or substantially parallel to the cylindrical light source 20 are configured by a plurality of weft yarn portions, and a plurality of orthogonal yarns that are orthogonal or substantially orthogonal to the cylindrical light source 20 are provided. It is comprised by the warp part of the thread | yarn. Specifically, in the second embodiment, the parallel yarn located on the upper side in the figure is formed of a weft portion 531 of the left yarn 53, a weft portion 541 of the right yarn 54, and a weft portion 513 of the upper yarn 51. Further, the parallel yarn located on the lower side of the figure is formed by a weft portion 532 of the left yarn 53, a weft portion 542 of the right yarn 54, and a weft portion 523 of the lower yarn 52. On the other hand, the orthogonal yarn located on the left side of the figure is formed by a warp yarn portion 511 of the upper yarn 51, a warp yarn portion 521 of the lower yarn 52, and a warp yarn portion 533 of the left yarn 53. Further, the orthogonal yarn located on the right side of the figure is formed by a warp yarn portion 512 of the upper yarn 51, a warp yarn portion 522 of the lower yarn 52, and a warp yarn portion 543 of the right yarn 54.

  As described above, the parallel yarns 26 and the orthogonal yarns 27 do not need to be formed by a single yarn, and a plurality of weft yarn portions and warp yarn portions of the plurality of yarns may constitute parallel yarns and orthogonal yarns, respectively. According to the support member 25 configured in this way, the warp portion of the warp yarn portion and the weft yarn portion is entangled with the weft yarn portion of another yarn and the bend portion of the warp yarn portion, thereby causing four forces to be received from the optical sheet group 14. Since it can disperse | distribute to each thread | yarn through a part, the support strength of the square area | region enclosed by four entanglement parts increases, and can support the optical sheet group 14 more stably.

  Also in the second embodiment, as shown in FIG. 10, the weft portion is always positioned above the warp portion (on the optical sheet side) at each entangled portion, thereby forming a gap between the parallel yarn and the optical sheet group 14. As a result, there is no shadow behind the yarn and uniform surface emission is ensured. In addition, since a single yarn (monofilament) such as a fishing line or an optical fiber is used as the yarn instead of the twisted yarn, no shadow caused by twisting of the yarn occurs when the twisted yarn is used.

  As shown in FIG. 10A, in the second embodiment as well, the parallel yarn is preferably disposed along a line obtained by projecting the cylindrical light source 20 perpendicularly to the optical sheet group 14.

Other embodiments

  In the above embodiment, it is preferable that the optical sheet group 14 disposed on the yarns 26 and 27, particularly the diffusion sheet 22 in contact with the yarns 26 and 27, is stretched in a state where tension is applied to itself. . FIG. 11 and FIG. 12 show a preferred form in which tension is applied to the diffusion sheet 22. In the form shown in FIG. 11, the left and right end portions of the diffusion sheet 22 are folded back inward, and the folded portion 63 is positioned between the frame 61 that holds and fixes the optical sheet group 14 and the housing side surface 62 that faces the frame 61. The folded end portion 64 is brought into contact with the outer surface of the housing 15 by the waist strength (elasticity) of the diffusion sheet 22, so that the diffusion sheet 22 is positioned on the opening 18 by the self-stretching function of the diffusion sheet 22. Apply tension. In the form shown in FIG. 12, arch-like cuts 65 and 66 projecting inwardly on the right and left and top and bottom of the diffusion sheet 22 are formed, and the tongue pieces 67 and 68 formed by the cuts 65 and 66 are formed in the casing. By elastically contacting the side surface 62, tension is applied to the diffusion sheet portion located on the opening 18 by the self-stretching function of the diffusion sheet 22. In the embodiment shown in FIG. 12, one tongue piece is formed on each side in the vertical direction and the horizontal direction, but a plurality of tongue pieces may be formed on each side.

  In addition, as shown in FIG. 13, the parallel yarn 26 in each embodiment, in particular, the parallel yarn portion adjacent to the diffusion sheet 22 may be bonded to the diffusion sheet 22 with an adhesive 70. In this case, the parallel yarn 26 is preferably fixed to the diffusion sheet 22 with a predetermined pretension applied thereto. The adhesive 70 is preferably transparent and colorless when solidified.

  Further, a triangular wedge-shaped cut 71 may be formed at the end of the diffusion sheet 22, and the parallel thread 26 or the orthogonal thread 27 may be hooked and held in the cut 71. In this case, the tension applied to the yarns 26 and 27 can be stably maintained. In particular, since the parallel yarn 26 can be reliably maintained in contact with the diffusion sheet 22, there is no shadow behind the parallel yarn 26.

  Furthermore, in the above description, the backlight device is provided with a plurality of cylindrical light sources, but one or more cylindrical light sources may be provided.

  Furthermore, in the above description, the embodiment in which the present invention is applied to the horizontally long backlight device and the liquid crystal display device has been described. However, as shown in FIG. 15, the backlight device and the liquid crystal display device having the vertically long light source unit 13 ″. The present invention is also applicable.

  As described above, according to the backlight device and the liquid crystal display device according to the present invention, it is possible to prevent the optical sheet group 14 from being bent and to secure a constant or substantially constant distance from the cylindrical light source 20. There is no clear lamp image (large brightness distribution) in the surface emission provided. Specifically, two backlight devices having flexible diffusion sheets are prepared, one parallel thread and orthogonal thread are stretched on one side, and no light is stretched on the other, and the light emitted from the diffusion sheet Luminance distribution (luminance distribution in a direction perpendicular to the cylindrical light source) was obtained. As a result, when the backlight device (conventional example) in which the yarn was not stretched was disposed horizontally, the deflection of the diffusion sheet was clearly confirmed visually. Further, as shown in FIG. 16, a high brightness portion (lamp image) clearly appeared corresponding to the position of the cylindrical light source. On the other hand, when the backlight device (invention) stretched with a thread is installed horizontally, the deflection of the diffusion sheet cannot be visually confirmed. As shown in FIG. 17, the high brightness portion corresponding to the position of the cylindrical light source is There was almost no. Moreover, the shadow of the thread was not confirmed in the surface emission emitted from the diffusion sheet.

The perspective view for demonstrating the basic principle of this invention. 1 is a perspective view showing a backlight device according to Embodiment 1 and a liquid crystal display device incorporating the backlight device. FIG. 3 is a cross-sectional view schematically showing a cross section of the liquid crystal display device shown in FIG. 2. The perspective view which shows the method of fixing a thread | yarn to a housing | casing. The rear perspective view of the backlight apparatus which shows the method of fixing a thread | yarn to a housing | casing. The perspective view which shows the various forms of the fixing tool which fixes a thread | yarn to a housing | casing. The perspective view which shows the state which attached the coil spring to the thread | yarn. The front view of the light source unit which shows the example of arrangement | positioning of a thread | yarn. FIG. 3 is an enlarged view showing a state in which a parallel yarn is wound around an orthogonal yarn. 1 is a front view of a light source unit used in a backlight device according to Embodiment 1. FIG. The figure which shows the method of applying tension | tensile_strength to a diffusion sheet. The figure which shows the other method of applying tension | tensile_strength to a diffusion sheet. Sectional drawing which shows the form which fixed the diffusion sheet and the thread | yarn with the adhesive agent. The figure which shows the form which hooks and fixes a thread | yarn to the notch of a diffusion sheet. The front view of a vertically long light source unit. The graph which shows the luminance distribution of the conventional backlight apparatus. The graph which shows the luminance distribution of the backlight apparatus of this invention.

Explanation of symbols

10: Liquid crystal display device 11: Backlight device 12: Liquid crystal panel 13: Light source unit 14: Optical sheet group 15: Housing 16: Bottom portion 17: Frame 18: Opening portion 19: Reflective material 20: Cylindrical light source 21: Light source support portion 22: diffusion sheet 23, 24: light collecting sheet 25: support member 26: parallel yarn (weft)
27: Orthogonal yarn (warp yarn)
28: Groove 29: Back 30: Fixing part 31: Screw 32: Protrusion part 33: Protrusion part 34: Hole 35: Rod 36: Protrusion part 37: Protrusion part 38: Ring 39: Protrusion part 40: Spring 41: Intersection part 51 ~ 54: Yarn

Claims (6)

An optical sheet (22), one cylindrical light source (20) arranged in parallel to the optical sheet (22) and spaced apart from the optical sheet (22), or a plurality of cylindrical light sources arranged in parallel (20), the illumination device (11) in which the light emitted from the cylindrical light source (20) is output via the optical sheet (22),
A first thread (26) made of a light-transmitting material and stretched in contact with or substantially in contact with the optical sheet (22) in a first direction parallel to the cylindrical light source (20) When,
A second thread (27) made of a light-transmitting material and stretched so as to intersect the first thread in a second direction perpendicular to the first direction;
At the intersection of the first thread (26) and the second thread (27), the first thread (26) is located on the optical sheet side and the second thread (27) is on the cylindrical light source side. Located in the
The lighting device, wherein the first yarn (26) and the second yarn (27) prevent the optical sheet (22) from being bent toward the cylindrical light source.   The said 1st thread | yarn (26) is arrange | positioned along the line which projected the said cylindrical light source (20) perpendicularly | vertically on the said optical sheet (22), or substantially along the line. 1 lighting device.   The lighting device according to claim 1 or 2, wherein the first yarn (26) and the second yarn (27) are made of a single wire.   The first yarn (26) has a diameter of 0.25 to 0.4 mm, and the second yarn (27) has a diameter of 0.15 to 0.4 mm. The lighting device according to any one of? A quadrangular frame portion comprising a quadrangular bottom portion (16) and an upper frame (171), a lower frame (172), a left frame (173), and a right frame (174) arranged along the edge of the bottom portion (16). A box-shaped housing (15) including: an optical sheet (22) arranged to cover the opening (18) of the housing (15), the optical sheet (22), and a bottom (16) In an illuminating device (11) having one or a plurality of cylindrical light sources (20) disposed between and extending in parallel with the upper frame (171) and the lower frame (172),
A support member interposed between the frame portion (17) and the optical sheet (22) to support the optical sheet (22) and prevent the optical sheet (22) from bending toward the cylindrical light source (20). (25)
The support member (25)
Both ends are supported by the left frame (173), a pair of weft portions (531, 532) extending from the left frame (173) toward the right frame (174), and a pair of weft portions (531, 532) and a left-hand thread (53) having a warp thread part (533),
Both ends are supported by the right frame (174), a pair of weft portions (541, 542) extending from the right frame (174) toward the left frame (173), and a pair of weft portions (541, 542) and a right-hand thread (54) having a warp thread part (543);
Both ends are supported by the upper frame (171), a pair of warp portions (511, 512) extending from the upper frame (171) toward the lower frame (172), and a pair of warp portions (511, 512) an upper thread (51) having a weft thread part (513) for connecting,
Both ends are supported by the lower frame (172), a pair of warp portions (521, 522) extending from the lower frame (172) toward the upper frame (171), and a pair of warp portions (521, 522) and a lower thread (52) having a weft thread part (523) connecting
The left and right bent portions of the warp yarn portion (511, 512) and the weft yarn portion (513) in the upper yarn (51) are connected to one weft portion (531, 541) in the left yarn (53) and the right yarn (54). It is intertwined with the bent part with the warp part (533, 543),
The left and right bent portions of the warp yarn portion (521, 522) and the weft yarn portion (523) in the lower yarn (52) are the other weft yarn portions (532, 542) in the left yarn (53) and the right yarn (54). Are intertwined with the bent part of the warp part (533, 543),
At the place where the warp portion (511, 512, 521, 522, 533, 543) and the weft portion (513, 531, 541, 532, 542, 523) are intertwined, the weft portion is located on the optical sheet side, and An illuminating device, wherein a warp portion is positioned on the cylindrical light source side.   6. A liquid crystal display device comprising the illumination device according to claim 1 and a liquid crystal panel.

Images