1. Field of the Invention
The present invention relates to a display device, and more particularly to a display device which includes a member disposed between a light guide plate and a display unit support member.
2. Description of the Related Art
A display device known in the art includes a member disposed between a light guide plate and a display unit support member (for example, see JP 2005-91971 A).
A liquid crystal display apparatus disclosed in JP 2005-91971 A includes a liquid crystal display panel, a mold (display unit support member) for supporting the liquid crystal display panel, a backlight device disposed on the mold on the side opposite to the liquid crystal display panel, and an optical compensation film. The backlight device includes a light guide plate, and a cold cathode fluorescent lamp disposed on a side end surface of the light guide plate. The optical compensation film is disposed on the liquid crystal display panel side surface of the light guide plate at a position between the liquid guide plate and the mold. A rubber cushion is provided between the optical compensation film (light guide plate) and the mold. The rubber cushion is disposed in a tight contact with the optical compensation film and the mold without compressive deformation.
According to the liquid crystal display apparatus disclosed in JP 2005-91971 A, which includes the rubber cushion disposed in a tight contact with the optical compensation film and the mold without compressive deformation, a clearance is produced between the mold and the optical compensation film (light guide plate) when the mold warps. In this case, light emitted from the cold cathode fluorescent lamp leaks through the clearance toward the liquid crystal display panel. As a result, a position around the cold cathode fluorescent lamp in the liquid crystal display panel becomes bright, while a position spaced away from the cold cathode fluorescent lamp in the liquid crystal display panel becomes dark. This situation causes a problem of uneven brightness (luminance unevenness) of a display image displayed on the liquid crystal display panel.
Preferred embodiments of the present invention provide a display device capable of significantly reducing or preventing uneven brightness (luminance unevenness) of a display image displayed on a display unit.
A display device according to an aspect of various preferred embodiments of the present invention includes a display unit; a light source unit; a light guide plate that includes a light entrance surface including a side end surface through which light emitted from the light source unit enters, and guides light emitted from the light source unit and entering the light entrance surface such that the light travels toward the display unit; a display unit support member disposed between the light guide plate and the display unit, and supporting the display unit; and an elastic member disposed between the light guide plate and the display unit support member, brought into contact with the light guide plate in an elastically deformed state of the elastic member, and having non-translucency to prevent transmission of light.
According to the display device of the one aspect of various preferred embodiments of the present invention as noted above, the non-translucent elastic member capable of preventing transmission of light is provided between the light guide plate and the display unit support member, and brought into contact with the light guide plate in a state of elastic deformation of the elastic member. In this case, the elastic member sandwiched between the light guide plate and the display unit support member and contacting the light guide plate in the state of elastic deformation is deformable in accordance with a change of the clearance between the light guide plate and the display unit support member as a result of a warp or the like produced in the display unit support member. This structure prevents generation of a clearance between the light guide plate and the elastic member. Accordingly, this structure reduces light emitted from the light source unit, passing through a clearance between the light guide plate and the elastic member, and entering the display unit, and thus reduces a bright area around the light source unit in the display unit, and a dark area spaced away from the light source unit in the display unit. As a result, uneven brightness (luminance unevenness) of a display image displayed on the display unit decreases.
The display device according to the one aspect of various preferred embodiments of the present invention preferably further includes an optical sheet disposed on the elastic member on the side opposite to the light source unit. In this case, at least a portion of the elastic member outside a side end surface of the optical sheet on the light source unit side is brought into contact with the light guide plate. According to this structure, the elastic member in contact with the light guide plate outside the side end surface of the optical sheet on the light source unit side reduces light emitted from the light source unit, passing through a clearance between the light guide plate and the elastic member, and entering the side end surface of the optical sheet on the light source unit side. This structure reduces a bright area around the light source unit in the display unit produced as a result of an effect of light having entered the side end surface of the optical sheet on the light source unit side, and a dark area away from the light source unit in the display unit, and thus reduces uneven brightness of a display image displayed on the display unit.
According to the display device of the above aspect of various preferred embodiments of the present invention, the light source unit preferably includes a plurality of light emitting elements arranged in an extension direction of a side end surface of the light guide plate, and the elastic member is preferably disposed to extend in the extension direction of the side end surface of the light guide plate. According to this structure, the elastic member reduces uneven brightness of a display image displayed on the display unit in a wide range of the display image in the extension direction of the side end surface of the light guide plate. In addition, the elastic member prevents generation of a clearance between the light guide plate and the elastic member, thus reducing light emitted from the respective light emitting elements as point light sources, passing through a clearance between the light guide plate and the elastic member, and entering the display unit. This structure reduces dark areas confronting portions between the light emitting elements on the light source unit side of the display unit, and extremely bright areas confronting the light emitting elements on the light source unit side of the display unit (so-called a phenomenon of hot spots), thus effectively reducing or preventing uneven brightness of a display image displayed on the display unit. Accordingly, this structure eliminates the necessity of reducing the intervals between the light emitting elements by raising the number of the light emitting elements for preventing hot spots, thus avoiding a rise of the number of the light emitting elements. In addition, this structure allows reduction of a distance between the light emitting elements and an opening of the display unit support member, while decreasing the hot spots without the need for a rise of the number of the light emitting elements. Accordingly, size reduction of the display device by the corresponding distance is achievable.
According to the display device of the above aspect of various preferred embodiments of the present invention, the elastic member is preferably made of non-translucent foam material, for example. According to this configuration, foam material is easy to elastically deform and also flexible when containing air. In this case, the elastic member exhibiting non-translucency elastically deforms with ease in such a manner as to come into tight contact with the light guide plate. This structure effectively prevents generation of a clearance between the light guide plate and the elastic member.
The display device of the above aspect of various preferred embodiments of the present invention preferably further includes a light guide plate support member disposed on the light guide plate on the side opposite to the elastic member, and configured to be less elastically deformable than the elastic member. This structure effectively prevents elastic deformation of the light guide plate support member rather than elastic deformation of the elastic member when the elastic member is pressed against the light guide plate toward the light guide plate support member for elastic deformation of the elastic member. Accordingly, this structure brings the elastic member into contact with the light guide plate with sufficient elastic deformation of the elastic member.
In this case, the light guide plate support member is preferably configured to be substantially non-deformable in an elastic manner. This structure brings the elastic member into contact with the light guide plate with sufficient elastic deformation of the elastic member and substantially without elastic deformation of the light guide plate support member.
According to the display device of the above aspect of various preferred embodiments of the present invention, the display unit support member preferably includes a recess on which the elastic member is disposed. According to this structure, the recess facilitates positioning of the elastic member on the display unit support member, and prevents positional deviation of the elastic member with respect to the display unit support member.
According to the display device of the above aspect of various preferred embodiments of the present invention, the elastic member is preferably disposed in such a condition as to press the side end surface of the optical sheet on the light source unit side, and surroundings of this side end surface. According to this structure, the elastic member pressing the side end surface of the optical sheet on the light source unit side, and surroundings of this side end surface prevents positional deviation of the optical sheet, thus reducing damage to the light guide plate caused by positional deviation of the optical sheet as a result of vibrations or the like.
As described above, reduction or prevention of uneven brightness of a display image displayed on a display unit is achievable according to various preferred embodiments of the present invention.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
Preferred embodiments according to the present invention are hereinafter described with reference to the drawings.
A configuration of a television 100 according to a first preferred embodiment of the present invention is now described with reference to
As illustrated in
As illustrated in
The bezel 12 is a frame member attached to the mold frame 13 from the front (Y1 direction) of the mold frame 13 in such a condition that the liquid crystal cell 11 is sandwiched between the bezel 12 and the mold frame 13.
The mold frame 13 is a frame member made of resin. As illustrated in
As illustrated in
The light guide plate 15 is a plate-shaped component made of resin, and has a rectangular shape elongated in the left-right direction (X direction). The optical sheets 14 are laminated on a front surface 15a of the light guide plate 15 on the Y1 side, while the reflection sheet 17 is disposed on a rear surface 15b of the light guide plate 15 on the Y2 side.
As illustrated in
The light source unit 16 includes a substrate 16a extended in the up-down direction (Z direction) corresponding to an extension direction of the light entrance surface 15c, and a plurality of LEDs 16b (point light sources) mounted on the substrate 16a on the light entrance surface 15c side (X2 side). The plurality of LEDs 16b are disposed substantially at equal intervals (intervals D) in the up-down direction along the light entrance surface 15c. The LEDs 16b are an example of “light emitting elements” according to preferred embodiments of the present invention.
As illustrated in
As illustrated in
The light source unit 16 is attached to the wall 18a on the X1 side. More specifically, a surface of the substrate 16a on the side (X1 side) opposite to the side where the LEDs 16b are mounted is bonded to the X2 side surface of the wall 18a via a bonding member 19. This structure allows attachment of the light source unit 16 to the back cover 18. This configuration therefore dissipates heat generated from the light source unit 16 via the back cover 18.
As illustrated in
The majority of light emitted from the LEDs 16b enters the light entrance surface 15c of the light guide plate 15. However, a portion of the light enters not the light guide plate 15 but a space between the front surface 15a of the light guide plate 15 and the mold frame 13. This light leaks toward the optical sheets 14 side (inside) via fine concavities and convexities which may be formed in the light guide plate 15, or a clearance which may be produced between the light guide plate 15 and the elastic member 4 as a result of a warp of the mold frame 13 or for other reasons. This leaking light enters the side end surface 14a of the optical sheets 14, or enters the liquid crystal cell 11. In this condition, areas confronting portions between the LEDs 16b become dark, while areas confronting the LEDs 16b become extremely bright (so-called a phenomenon of hot spots), on the light source unit 16 side of the liquid crystal cell 11. For reduction of these hot spots, decrease in the intervals D between the LEDs 16b (see
According to the first preferred embodiment, the elastic member 4 is configured to come into contact with the light guide plate 15 in a state of elastic deformation (compressive deformation), and exhibit non-translucency to prevent transmission of light, as illustrated in
According to the first preferred embodiment, therefore, the elastic member 4 reduces leakage of light toward the optical sheets 14 side (inside) after emission of the light from the LEDs 16b of the light source unit 16 toward the position between the mold frame 13 and the light guide plate 15. This structure prevents generation of hot spots even when the distance L between the LEDs 16b and the opening 13d of the mold frame 13 is reduced without changing the number of the LEDs 16b.
The spacer member 5 has a quadrangular prism shape similar to the shape of the elastic member 4. The spacer member 5 extends in the up-down direction (Z direction) corresponding to the extension direction of the light entrance surface 15c of the light guide plate 15. The spacer member 5 is disposed on the light source unit 16 side (X1 side) at a position between the light guide plate 15 (reflection sheet 17) and the back cover 18, and on the side (Y2 side) of the light guide plate 15 opposite to the elastic member 4 disposed on the front side (Y1 side) of the light guide plate 15. This structure allows the spacer member 5 to support the light guide plate 15 via the reflection sheet 17. The spacer member 5 is fixed to the back cover 18 via a not-shown double sided tape, for example. The spacer member 5 is disposed at a position overlapping with the elastic member 4 in the front-rear direction (Y direction).
The spacer member 5 is constituted by silicone rubber that is substantially non-deformable in an elastic manner. In other words, the spacer member 5 is less elastically deformable than the elastic member 4 made of urethane foam. This structure allows elastic deformation of the elastic member 4, rather than that of the spacer member 5, when the elastic member 4 is pressed against the light guide plate 15.
In addition, the spacer member 5 is configured to become a positioning reference for the light guide plate 15 in the front-rear direction (Y direction). More specifically, a thickness t2 of the spacer member 5 in the front-rear direction is adjusted such that the center of the light guide plate 15 in the front-rear direction (thickness direction) and the center of the LEDs 16b in the front-rear direction are aligned with substantially the same position when the light guide plate 15 is positioned on the front side (Y1 side) surface of the spacer member 5. According to this structure, the mold frame 13, the bezel 12, and the elastic member 4 do not affect the positioning of the light guide plate 15 in the front-rear direction, wherefore parameters affecting this positioning are allowed to be limited only to the positions of the LEDs 16b in the front-rear direction, the thickness t2 of the spacer member 5 in the front-rear direction, the thickness of the reflection sheet 17 in the front-rear direction, and the center position of the light guide plate 15 in the front-rear direction. The thickness of the reflection sheet 17 is sufficiently small and substantially ignorable. Accordingly, this structure allows reduction of the number of the parameters affecting the positioning, thus effectively reducing positional deviation between the light guide plate 15 and the LEDs 16b in the front-rear direction.
The elastic member 4 and the spacer member 5 are disposed at positions overlapped with the rear portion (Y2 direction) of the mold frame 13 in the front-rear direction (Y direction). According to this structure, the elastic member 4 and the spacer member 5 are located at positions not visible from the liquid crystal cell 11 side (front side). This arrangement reduces generation of unevenness in a display image displayed on the liquid crystal cell 11, as a problem caused by the presence of the elastic member 4 and the spacer member 5.
According to the first preferred embodiment, the following advantages are achieved.
According to the first preferred embodiment discussed above, the non-translucent elastic member 4 capable of preventing transmission of light is provided between the light guide plate 15 and the mold frame 13, and brought into contact with the light guide plate 15 in a state of elastic deformation of the elastic member. In this case, the elastic member 4 sandwiched between the light guide plate 15 and the mold frame 13 and contacting the light guide plate 15 in the state of elastic deformation is deformable in accordance with a change of the clearance between the light guide plate 15 and the mold frame 13 as a result of a warp or the like produced in the mold frame 13. This structure prevents generation of a clearance between the light guide plate 15 and the elastic member 4. Accordingly, this structure reduces light emitted from the light source unit 16, passing through a clearance between the light guide plate 15 and the elastic member 4, and entering the liquid crystal cell 11, and thus reduces a bright area around the light source unit 16 in the liquid crystal cell 11, and a dark area away from the light source unit 16 in the liquid crystal cell 11. As a result, uneven brightness (luminance unevenness) of a display image displayed on the liquid crystal cell 11 decreases.
According to the first preferred embodiment, the elastic member 4 is brought into contact with the front surface 15a of the light guide plate 15 on the outside (X1 side) of the side end surface 14a of the optical sheets 14 on the light source unit 16 side (X1 side). According to this structure, the elastic member 4 in contact with the light guide plate 15 outside the side end surface 14a of the optical sheets 14 reduces light emitted from the light source unit 16, passing through a clearance between the light guide plate 15 and the elastic member 4, and entering the side end surface 14a of the optical sheets 14. Accordingly, this structure reduces a bright area around the light source unit 16 in the liquid crystal cell 11 that is produced as a result of an effect of light having entered the side end surface 14a of the optical sheets 14, and a dark area spaced away from the light source unit 16 in the liquid crystal cell 11, and thus reduces uneven brightness of a display image displayed on the liquid crystal cell 11.
According to the first preferred embodiment, the plurality of LEDs 16b are disposed substantially at equal intervals (intervals D) in the up-down direction (Z direction) along the light entrance surface 15c (side end surface on the X1 side), while the elastic member 4 extends in the up-down direction corresponding to the extension direction of the light entrance surface 15c of the light guide plate 15. According to this structure, the elastic member 4 reduces uneven brightness of a display image displayed on the liquid crystal cell 11 in a wide range of the display image in the up-down direction corresponding to the extension direction of the side end surface of the light guide plate 15. In addition, the elastic member 4 prevents generation of a clearance between the light guide plate 15 and the elastic member 4, thus reducing light emitted from the LEDs 16b as point light sources, passing through a clearance between the light guide plate 15 and the elastic member 4, and entering the liquid crystal cell 11. This structure reduces dark areas confronting portions between the LEDs 16b on the light source unit 16 side of the liquid crystal cell 11, and extremely bright areas confronting the LEDs 16b on the light source unit 16 side of the liquid crystal cell 11 (so-called a phenomenon of hot spots), thus effectively reducing uneven brightness of a display image displayed on the liquid crystal cell 11. Accordingly, this structure eliminates the necessity of reducing the intervals between the LEDs 16b by raising the number of the LEDs 16b to prevent hot spots, thus avoiding a rise of the number of the LEDs 16b. In addition, this structure allows reduction of the distance L between the LEDs 16b and the opening 13d of the mold frame 13, while decreasing hot spots without the need for a rise of the number of the LEDs 16b. Accordingly, this structure allows reduction of the length of a frame-shaped portion of the frame-shaped mold frame 13 (length in the X direction in
According to the first preferred embodiment, the elastic member 4 is made of foam material (urethane foam) exhibiting non-translucency, and therefore is easy to elastically deform and also flexible when containing air. In this case, the elastic member 4 exhibiting non-translucency elastically deforms with ease to come into tight contact with the light guide plate 15. This structure effectively prevents generation of a clearance between the light guide plate 15 and the elastic member 4.
According to the first preferred embodiment, the spacer member 5 that is substantially non-deformable in an elastic manner (less elastically deformable than elastic member 4) is disposed on the side (rear side or Y2 side) of the light guide plate 15 opposite to the elastic member 4. This structure effectively prevents elastic deformation of the spacer member 5 rather than elastic deformation of the elastic member 4 when the elastic member 4 is pressed against the light guide plate 15 toward the spacer member 5 (rear side) for elastic deformation of the elastic member 4. Accordingly, this structure brings the elastic member 4 into contact with the light guide plate 15 with sufficient elastic deformation of the elastic member 4 and substantially without elastic deformation of the spacer member 5.
According to the first preferred embodiment, the mold frame 13 includes the recess 13c to which the elastic member 4 is fixed. According to this structure, the recess 13c facilitates positioning of the elastic member 4 on the mold frame 13, and prevents positional deviation of the elastic member 4 with respect to the mold frame 13.
A second preferred embodiment of the present invention is hereinafter described with reference to
As illustrated in
The elastic member 204 exhibiting non-translucency is larger than the elastic member 4 according to the first preferred embodiment (see
Other configurations of the second preferred embodiment are similar to the corresponding configurations of the first preferred embodiment.
According to the second preferred embodiment, the following advantages are achieved.
According to the second preferred embodiment discussed above, the non-translucent elastic member 204 capable of preventing light transmission is provided between the light guide plate 15 and the mold frame 213, and brought into contact with the light guide plate 15 in a state of elastic deformation of the elastic member 204. As in the first preferred embodiment, this structure reduces a bright area in the vicinity of the light source unit 16 in the liquid crystal cell 11, and a dark area away from the light source unit 16 in the liquid crystal cell 11, thus decreasing uneven brightness (luminance unevenness) of a display image displayed on the liquid crystal cell 11.
In addition, according to the second preferred embodiment, the elastic member 204 is configured to press the side end surface 14a of the optical sheet 14 on the light source unit 16 side (X1 side) and the surroundings of the side end surface 14a. According to this structure, the elastic member 204 pressing the side end surface 14a of the optical sheets 14 and the surroundings of the side end surface 14a prevents positional deviation of the optical sheets 14, thus reducing damage to the light guide plate 15 caused by positional deviation of the optical sheets 14 as a result of vibrations or the like.
Other advantages produced by the second preferred embodiment are similar to the corresponding advantages of the first preferred embodiment.
A third preferred embodiment of the present invention is hereinafter described with reference to
As illustrated in
The spacer member 305 is constituted by resin material that is substantially non-deformable in an elastic manner. Accordingly, the spacer member 305 is less elastically deformable than the elastic member 4 (see
As illustrated in
Other configurations according to the third preferred embodiment are similar to the corresponding configurations of the first preferred embodiment.
According to the third preferred embodiment, the following advantages are achieved.
In the third preferred embodiment, as discussed above, the hook-shaped engaging portions 305a and the hemispherical engaging portion 305b capable of engaging with the back cover 318 are provided on the spacer member 305. This structure eliminates the need for fixation between the spacer member 305 and the back cover 318 via an additional double sided tape or the like, thus reducing the number of parts. In addition, sliding of the spacer member 305 upward (Z1 direction) completes positioning and fixation between the spacer member 305 and the back cover 318. This structure facilitates positioning and fixation of the spacer member 305, thus increasing assembly efficiency of the display module 301.
Other advantages provided by the third preferred embodiment are similar to the corresponding advantages of the first preferred embodiment.
The plurality of LEDs 16b are mounted on an elongated rectangular substrate 16a at substantially equal intervals (intervals D) along the direction of length. The light source unit 16 that includes the plurality of LEDs 16b and the substrate 16a is disposed such that the arrangement direction of the LEDs 16b is parallel or substantially parallel to the light entrance surface 15c (side end surface on the X1 side) of the light guide member 15. Furthermore, the elastic member 4 is disposed on the front-side surface 15a of the light guide member 15 so as to be parallel or substantially parallel to the direction of arrangement of the plurality of LEDs 16b. As shown in the figures, the arrangement of the elastic member 4 and the light source unit 16 is set such that the position of the upper (Z1 side) end of the elastic member 4 in the up-down direction (Z direction) is located farther toward the upper side (Z1 side) than the position of the upper (Z1 side) end of the uppermost (Z1 side) LED 16b in the Z direction.
Moreover, although this is not shown, the arrangement of the elastic member 4 and the light source unit 16 is set such that the position of the lower (Z2 side) end of the elastic member 4 in the up-down direction (Z direction) is located farther toward the lower side (Z2 side) than the position of the lower (Z2 side) end of the lowermost (Z2 side) LED 16b in the Z direction.
Moreover, although this is not shown, the arrangement of the elastic member 4 and the light source unit 16 is set such that there is no overlapping of the display area A and an area where light emitted from the lowermost (Z2 side) LED 16b out of the plurality of LEDs 16b leaks in the left-right direction (X direction) without being blocked by the elastic member 4.
As was described above, by setting the arrangement of the elastic member 4 and the light source unit 16, light leaking from the LEDs 16b is not directed toward corner portions of the display area A. Accordingly, it is possible to prevent luminance unevenness caused by the luminance at a corner portion of the display area A from becoming higher than the luminance in other portions of the display area.
It should be understood that the respective preferred embodiments disclosed herein are only presented by way of example in any points, and are not intended to limit the present invention. The scope of the present invention is defined not by the description of the foregoing preferred embodiments, but only the scope of the appended claims. Accordingly, the scope of the present invention includes all modifications (modified examples) contained in senses and scopes equivalent to the appended claims.
For example, while the television has been discussed according to the first through third preferred embodiments as an example of the display device of the present invention, the present invention is not limited to this example. The present invention is applicable to other types of display devices as well as a television. For example, the present invention is applicable to ordinary types of display devices such as a display device for a PC (Personal Computer).
While the elastic members 4 and 204 are preferably constituted by urethane foam according to the first through third preferred embodiments discussed herein, the present invention is not limited to this example. The elastic member according to the present invention may be an arbitrary component which is elastically deformable. For example, the elastic member may be constituted by silicone rubber or expanded polyethylene (EPE) having low solidity. It is preferable that the elastic member is constituted by foam material.
While the spacer members 5 and 305 are preferably constituted by silicone rubber substantially non-deformable in an elastic manner according to the first through third preferred embodiments discussed herein, the present invention is not limited to this example. The spacer member according to the present invention may be an elastically deformable component. In this case, it is preferable that the spacer member is a component less elastically deformable than the elastic member.
While the spacer member 5 (305) preferably is additionally provided between the light guide plate 15 and the back cover 18 (318) according to the first through third preferred embodiments discussed herein, the present invention is not limited to this example. According to the present invention, a projection may be formed integrally with the back cover, which projection projects toward the light guide plate with a top portion of the projection in contact with the light guide plate. This structure eliminates the need for equipping the spacer member, wherefore reduction of the number of parts is achievable.
While the mold frame 13 as the recess 13c on which the elastic member 4 preferably is provided according to the first preferred embodiment discussed herein, the present invention is not limited to this example. According to the present invention, such a configuration is allowed which includes a display module 401 whose mold frame 413 contains no recess as in a modified example of the first preferred embodiment illustrated in
While the light source unit 16 preferably includes the plurality of LEDs 16b (point light sources) according to the first through third preferred embodiments, the present invention is not limited to this example. The light source unit according to the present invention may be a line light source such as a fluorescent lamp instead of LEDs.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
Number | Date | Country | Kind |
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2014-111516 | May 2014 | JP | national |