JP2009094018A - Back light unit and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight unit or the like in which an optical sheet such as a diffusion sheet cannot be seen from sideways when mounted on a liquid crystal display device. <P>SOLUTION: In the diffusion sheet 25 included in the backlight unit 21, the end of a face to receive light from a fluorescent tube 22, that is a light receiving face 25s, is black BK. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a backlight unit that emits light to a liquid crystal display panel and a liquid crystal display device on which the backlight unit is mounted.

  Usually, a liquid crystal display device is equipped with a liquid crystal display panel that displays light by receiving light from a backlight unit, and the edge of the liquid crystal display panel is covered with a bezel. Therefore, the user sees the frame-shaped bezel at the same time as viewing the screen of the liquid crystal display panel.

Then, if the surface of the bezel (the surface that can be viewed simultaneously with the liquid crystal display panel) is excessively large, the liquid crystal display panel becomes not only difficult for the user to see, but also the size of the liquid crystal display device itself increases. Therefore, recently, there has been a demand for a narrow frame that reduces the area of the surface of the bezel, and various liquid crystal display devices that attempt to achieve the demand have been disclosed (Patent Document 1, etc.).
JP-A-2005-241964

  However, with the narrowing of the frame, a new problem has arisen. The problem is that when the user looks at the liquid crystal display device (in detail, a liquid crystal display panel) from an oblique direction, members inside the liquid crystal display device are seen.

  For example, as shown in the cross-sectional view of the liquid crystal display device 189 shown in FIG. 8, when the user looks at the liquid crystal display device 189 from an oblique direction (when viewed from the perspective), the edge inside the backlight unit 121 that should be hidden by the bezel 151, particularly the back The edge of the diffusion sheet 125 mounted on the light unit 121 can be seen (in FIG. 8, eye indicates the user's eyes and the white arrow indicates the tip of the user's line of sight).

  This is the first cause that the surface area of the bezel 151 becomes narrow. A second cause is that the distance from the diffusion sheet 125 to the liquid crystal display panel 111 is shortened.

  The liquid crystal display panel 111 is normally held by being sandwiched between the bezel 151 and one member of the backlight unit 121 (for example, the built-in chassis 141 and the backlight chassis 131). However, when the area of the surface of the bezel 151 is reduced, the pressing force on the liquid crystal display panel 111 is weakened. In such a case, the liquid crystal display panel 111 may be bent toward the backlight unit 121.

  If the liquid crystal display panel 111 is bent, the liquid crystal display panel 111 may come into contact with members of the backlight unit 121. Therefore, in the liquid crystal display device 189 with a narrow frame, the distance V between the liquid crystal display panel 111 and the backlight unit 121 is relatively wide. Then, in the case of a perspective view, the inside of the liquid crystal display device 189 can be more easily seen, and a member through which light passes, such as the diffusion sheet 125, becomes conspicuous. In addition, the fact that the diffusion sheet 125 is seen in this way can be said to be a reduction in image quality as the liquid crystal display panel 111.

  The present invention has been made in view of the above situation. An object of the present invention is to provide a backlight unit or the like in which an optical sheet such as a diffusion sheet cannot be seen in perspective when mounted on a liquid crystal display device.

  The backlight unit is a light source that emits light, and a sheet that receives and emits light from the light source. At least a light receiving surface of the sheet has a black end, and an optical sheet that supports the edge of the optical sheet. 1 support body and the black 2nd support body which pinches | interposes the edge of an optical sheet with the 1st support body.

  For example, when this backlight unit is mounted on a liquid crystal display device together with a liquid crystal display panel, and the user views the liquid crystal display panel from an oblique direction (in a perspective view), the edge of the optical sheet, particularly the edge of the light receiving surface (edge) Appears to float between the side surface of the optical sheet and the light receiving surface due to light refraction. However, if the end of the light receiving surface of the optical sheet is black, the portion is assimilated to the black second support and is not easily seen in perspective.

  Another example of the backlight unit is a light source that emits light and a sheet that receives and emits light from the light source, and includes a curved surface in a part of the edge of the sheet, thereby forming a tapered edge. An optical sheet; and a first support that supports an edge of the optical sheet.

  If it becomes like this, the edge part will reduce in the edge of an optical sheet. That is, in the case of strabismus, there are fewer conspicuous parts.

  The backlight unit is a light source that emits light and a sheet that receives and emits light from the light source, and includes a curved surface in a part of the edge of the sheet, thereby forming a tapered edge, and at least An optical sheet in which the end of the light receiving surface of the sheet is black, a first support that supports the edge of the optical sheet, and a black second support that sandwiches the edge of the optical sheet with the first support; , May be included.

  In this case, not only the portion that is conspicuous in the perspective view is small, but also the small portion is assimilated with the black second support, so that the edge of the optical sheet is not conspicuous more effectively.

  The end of the exit surface of the optical sheet may be black, or the side surface of the optical sheet from the end of the light receiving surface to the end of the exit surface may be black.

  Moreover, the method of making a part of the diffusion sheet black is not particularly limited. For example, a black portion of the optical sheet may be formed by painting, a chemical treatment, or a black seal may be attached.

  By the way, as an example in which the edge of the optical sheet tapers, the side surface of the optical sheet is curved. In particular, in such a curved surface, the center of curvature is located on the optical sheet side with respect to the curved surface itself.

  There are several examples of such optical sheets. For example, if the side where the light receiving surface of the optical sheet is located is the light receiving side with the optical sheet as a boundary, the end of the light receiving surface is positioned inside the end of the light emitting surface of the optical sheet, so that the curved surface of the optical sheet An example in which the side surface is inclined toward the light receiving side is given.

  Further, when the side where the exit surface of the optical sheet is located is the exit side with the optical sheet as a boundary, the end of the exit surface is located inside the end of the light receiving surface of the optical sheet, so that the curved surface of the optical sheet is An example in which the side surface is inclined toward the emission side is given.

  As yet another example, at least one of the joint between the side surface and the light receiving surface in the optical sheet, and the joint between the side surface and the emission surface in the optical sheet is a curved surface, the edge of the optical sheet is tapered, There is an example in which the center of curvature of the curved surface is located on the optical sheet side with the curved surface as a boundary.

  By the way, it is desirable that the first support is at least one of a backlight chassis that houses the light source and a light source holder that supports the light source. The built-in chassis that sandwiches the edge of the optical sheet with the backlight chassis is more preferably the second support.

  Alternatively, the first edge portion facing the edge of the optical sheet is supported by a backlight chassis that houses the light source as the first support, and the second edge portion of the optical sheet other than the first edge portion is It is desirable that the light source is supported by a light source holder that supports the light source as the first support. The built-in chassis that sandwiches the edge of the optical sheet with the backlight chassis is more preferably the second support.

  Note that a liquid crystal display device including the above backlight unit and a liquid crystal display panel positioned so as to cover the optical sheet in order to receive light emitted from the backlight unit can also be said to be the present invention.

  In such a liquid crystal display device, it is desirable that a black light-shielding mask pattern is included at the edge of the liquid crystal display panel.

  In this case, the black portion of the optical sheet is not only assimilated to the black second support, but also assimilated with the black light-shielding mask pattern, and is less noticeable in perspective.

  According to the present invention, the optical sheet in the backlight unit (and thus the liquid crystal display device) is not conspicuous when it is perspective.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to the drawings. For convenience, hatching, member codes, and the like may be omitted. In such a case, other drawings are referred to. Moreover, the black circle on the drawing means a direction perpendicular to the paper surface.

  FIG. 7 is an exploded perspective view of the liquid crystal display device. 1 is a cross-sectional view taken along the line A-A 'of the liquid crystal display device shown in FIG. 7, and FIG. 2 is a cross-sectional view taken along the line B-B'. As shown in these drawings, the liquid crystal display device 89 includes a liquid crystal display panel 11, a backlight unit 21, and a bezel 51.

  In the liquid crystal display panel 11, an active matrix substrate 12 including a switching element such as a TFT (Thin Film Transistor) and a counter substrate 13 facing the active matrix substrate 12 are bonded together with a sealing material (not shown). Then, liquid crystal (not shown) is injected into the gap between the substrates 12 and 13.

  Since the liquid crystal display panel 11 is a non-light emitting display panel, the liquid crystal display panel 11 is positioned so as to cover the backlight unit 21 and exhibits a display function by receiving light from the backlight unit 21 (backlight light). Therefore, if the light from the backlight unit 21 can uniformly irradiate the entire surface of the liquid crystal display panel 11, the display quality of the liquid crystal display panel 11 is improved.

  As shown in FIG. 1, a film (System On Film) 15 provided with various elements and wirings including a driver (source driver) 14 for controlling driving of pixels is connected to the active matrix substrate 12. Therefore, an electrical signal used for pixel drive control is via the film 15 and the control board 16. Further, in order to improve contrast, a black mask BM pattern (light-shielding mask pattern) is interposed between the active matrix substrate 12 and the counter substrate 13 in the vicinity of the edge of the liquid crystal display panel 11.

  The backlight unit 21 includes a fluorescent tube (light source) 22 lamp holder 23, a backlight chassis 31, a reflection sheet 24, a diffusion sheet 25, a lens sheet 26, and a built-in chassis 41 in order to generate backlight light.

  The fluorescent tube (linear light source) 22 has a linear shape (bar shape, cylindrical shape, etc.) and is mounted in plural in the backlight unit 21 (however, for convenience, only a part of the number is shown in the drawing). Have been).

  The lamp holder (first support, light source holder) 23 is a set of two block-like members, and holds the fluorescent tube 22. More specifically, each lamp holder 23 supports one end and the other end of the fluorescent tube 22 so that the fluorescent tube 22 is mounted on the backlight unit 21. Further, in order to more stably mount the fluorescent tube 22 on the backlight unit 21, a lamp clip (not shown) for holding the fluorescent tube 22 may be included.

  In addition, the kind of the fluorescent tube 11 is not limited, For example, a cold cathode tube and a hot cathode tube may be sufficient. Further, hereinafter, the parallel direction of the fluorescent tubes 22 (the direction in which the fluorescent tubes 22 are arranged in a straight line) is the X direction, the extending direction of the fluorescent tubes 22 is the Y direction, and the direction perpendicular to both the X direction and the Y direction is the Z direction. Called.

  The backlight chassis (first support) 31 is parallel to the in-plane direction of the housing 33 having opposing walls (opposing walls) 32 and 32 and the bottom surface 34 of the housing 33 from the front ends of the opposing walls 32 and 32. And flanges 35 and 35 extending away from the bottom surface 34. The accommodating body 33 of the backlight chassis 31 accommodates various members such as the fluorescent tube 22.

  The reflection sheet (optical sheet) 24 is a reflection member that covers the bottom surface 34 of the container 33 and reaches the flange pieces 35 and 35. The reflection sheet 24 reflects light from the fluorescent tube 22 located in the container 33. More specifically, the reflection sheet 24 reflects a part of the radial light emitted from the fluorescent tube 22 (radial light centered on the fluorescent tube 22) and guides it to the open surface of the container 33.

  As shown in FIG. 1, the facing wall 32 from the flange piece 35 to the bottom surface 34 of the backlight chassis 31 falls away from the bottom surface 34 and is inclined. This is because the reflection sheet 24 covering the opposing wall 32 is inclined, and the light from the fluorescent tube 22 can be efficiently guided to the liquid crystal display panel 11.

  Further, the constituent member itself of the backlight chassis 31 may be made of a resin or metal having a reflecting function. This is because the reflection sheet 24 can be removed if this is the case.

  The diffusion sheet (optical sheet) 25 is a member formed of a resin such as polyethylene terephthalate having a function of scattering light and a function of diffusing light. In the diffusion sheet 25, a part of the opposite edge (first edge part 1AR) is supported by the flange pieces 35, 35 of the backlight chassis 31, and the remaining opposite edge part (second edge part 2AR) is supported. The top surface 23u of the lamp holder 23 is supported (the top surface 23u is one surface facing the liquid crystal display panel 11 side in the lamp holder 23).

  That is, the lamp holders 23 and 23 are positioned at the edge of the bottom surface 34 where the opposing walls 32 and 32 are not positioned, so that the lamp holders 23 and 23 and the opposing walls 32 and 32 are arranged in a frame shape. Therefore, the edge of the diffusion sheet 25 is supported by the frame-shaped lamp holders 23 and 23 and the opposing walls 32 and 32.

  Then, the diffusion sheet 25 is positioned so as to cover the fluorescent tubes 22 arranged in parallel. As a result, when light traveling from the fluorescent tube 22 is incident on the diffusion sheet 25, the light is scattered and diffused and spreads in the in-plane direction. In the diffusion sheet 25, the light receiving surface 25i is the surface that receives light from the fluorescent tube 22, the light emitting surface 25o is the surface that emits light that is refracted from the light receiving surface 25i, and the light receiving surface 25i and the light emitting surface 25o. A surface to be sandwiched is defined as a side surface 25s.

  The lens sheet (optical sheet) 26 is, for example, a lens having a lens shape in the sheet surface and deflecting (condensing) light radiation characteristics, and is positioned so as to cover the diffusion sheet 25. Therefore, the opposite edges of the lens sheet 26 are supported by the flanges 35 and 35 that support the diffusion sheet 25 and the top surfaces 23u and 23u of the lamp holders 23 and 23. When the light traveling from the diffusion sheet 25 is incident on the lens sheet 26, the light is collected and the light emission luminance per unit area is improved.

  The built-in chassis (second support) 41 is a frame-like black member that supports the liquid crystal display panel 11 and holds the diffusion sheet 25 and the lens sheet 26, and includes a support piece 42 and a skirt piece 43.

  The support piece 42 covers the edge of the diffusion sheet 25 and the edge of the lens sheet 26 supported by the flange piece 35 of the backlight chassis 31 and the top surface 23u of the lamp holder 23, and is opposite to the surface to be covered (surface). The edge of the display panel 11 is supported. On the other hand, the skirt piece 43 hangs down from the outer edge of the support piece 42 and surrounds the opposing wall 32 of the container 33 in the backlight chassis 31.

  The bezel 51 is a member that sandwiches the liquid crystal display panel 11 positioned on the built-in chassis 41 as an exterior as the liquid crystal display device 89, and includes a sandwiching piece 52 and a surrounding wall piece 53.

  The sandwiching piece 52 sandwiches the edge of the liquid crystal display panel 11 with the support piece 42 of the built-in chassis 41. On the other hand, the surrounding wall piece 53 hangs down from the outer edge of the sandwiching piece 52 and surrounds the outer surface of the hem piece 43 of the built-in chassis 41.

  In the backlight unit 21 as described above, the fluorescent tubes 22 arranged in parallel emit light by an AC signal supplied from an inverter (not shown). Such light reaches the diffusion sheet 25 directly, or reaches the diffusion sheet 25 after being reflected by the reflection sheet 24. Further, the light that has reached the diffusion sheet 25 passes through the lens sheet 26 while being diffused, and is emitted as backlight light with enhanced emission luminance. Then, the backlight light reaches the liquid crystal display panel 11, and the liquid crystal display panel 11 displays an image.

  Here, the diffusion sheet 25 will be described in detail. As shown in FIGS. 1 and 2, the vicinity of the side surface 25s of the diffusion sheet 25 is black BK. Specifically, the side surface 25s and the lower end of the side surface 25s (the end of the side surface 25s close to the fluorescent tube 22 side; that is, the end of the light receiving surface 25i) P extend to the light receiving surface 25i are black BK. .

  When the black BK is in this way, as shown in FIG. 1 and FIG. 2 (EYE indicates the user's eyes and the white arrow indicates the tip of the user's line of sight), the user looks at the liquid crystal display device 89 from an angle. In the case of a perspective view, the side surface 25s of the diffusion sheet 25 is not conspicuous. The reason is as follows.

  Normally, in the case of a perspective view, the end P of the light receiving surface 25i (the lower end P of the side surface 25s) appears to float between the side surface 25s and the light receiving surface 25i due to light refraction. However, if the end of the light receiving surface 25i is black BK, the black BK portion is assimilated to the black built-in chassis 41 (looks the same), and is difficult for the user to visually recognize. In addition, in the case of a perspective view, since the black mask BM pattern located at the edge of the liquid crystal display panel 11 can be seen, the edge P (the edge of the light receiving surface 25i) of the light receiving surface 25i of the diffusion sheet 25 is increasingly inconspicuous.

  In the case of a perspective view, the most conspicuous side surface 25s of the diffusion sheet 25 is the lower end P that is an edge (eg, a right angle). Therefore, at least the lower end P of the side surface 25s only needs to be black. However, in the vicinity of the side surface 25s of the diffusion sheet, for example, as shown in FIGS. 1 and 2, in addition to the lower end P of the side surface 25s, the entire surface of the side surface 25s and the portion extending from the lower end P of the side surface 25s to the light receiving surface 25i. When these are black, those black portions BK are certainly not noticeable.

  In addition to the lower end P of the side surface 25s, the entire surface of the side surface 25s and the portion extending from the upper end Q (the edge of the output surface 25o) of the side surface 25s to the output surface 25o may be black (not shown). . Even in such a case, the side surface 25s becomes inconspicuous in a perspective view.

  There are many methods for making a part of the diffusion sheet 25 black. For example, black painting, chemical treatment for scoring, and sticking of a black seal can be mentioned. Moreover, since black is only an example capable of absorbing light, other colors may be used. In short, it is sufficient if assimilation is possible.

[Embodiment 2]
A second embodiment will be described. In addition, about the member which has the same function as the member used in Embodiment 1, the same code | symbol is attached and the description is abbreviate | omitted.

  In the first embodiment, when the edge of the diffusion sheet 25, specifically, at least the end of the light receiving surface 25i of the diffusion sheet 25 is black BK, the side surface 25s (at least the lower end P) of the diffusion sheet 25 is a perspective view. Became inconspicuous. However, in order to make the side surface 25s of the diffusion sheet 25 inconspicuous, it is not essential that the portion is black BK.

  For example, as shown in the partially enlarged view of FIG. 3A, the edge of the diffusion sheet 25 may be a tapered edge by including a curved surface in part. More specifically, when the side surface 25s of the diffusion sheet 25 is curved, the edge of the diffusion sheet 25 tapers. However, the center of curvature of the curved surface is located on the diffusion sheet 25 side with the curved surface (side surface 25s) as a boundary.

  In particular, as shown in FIG. 3A, in the diffusion sheet 25, the end P of the light receiving surface 25 i is positioned inside the end Q of the emission surface 25 o, so that the curved side surface 25 s becomes the light receiving side (with the diffusion sheet 25 as a boundary). It is desirable to tilt toward the light receiving surface 25i side.

  When the side surface 25s is inclined in such a manner as described above, the angle (δ) between the side surface 25s and the light receiving surface 25i in the diffusion sheet 25 becomes an obtuse angle instead of a right angle, and the degree of edge decreases. Therefore, in the case of a perspective view, the lower end P of the side surface 25s becomes inconspicuous.

  As shown in FIG. 3B, in the diffusion sheet 25, when the end Q of the emission surface 25o (the upper end Q of the side surface 25s) is positioned inside the end P of the light receiving surface 25i, the curved side surface 25s is emitted. You may incline toward the side (The side where the output surface 25o is located on the boundary of the diffusion sheet 25).

  Thus, when the side surface 25s is inclined to look up, the lower end P of the side surface 25s is an edge, but the angle (θ) between the side surface 25s and the exit surface 25o in the diffusion sheet 25 is not a right angle but an obtuse angle. become.

  In this case, the lower end P of the side surface 25s becomes inconspicuous by visually recognizing the side surface 25s that is a gentle curved surface before the lower end P of the side surface 25s is obtained. Alternatively, the lower end P of the side surface 25s becomes inconspicuous by visually recognizing light that is reflected in a complicated manner due to the side surface 25s of the curved surface (light that travels around the side surface 25s).

  Further, as shown in FIG. 3C, the side surface 25s may be a curved surface including a portion inclined toward the light receiving side and a portion inclined toward the emission side. More specifically, the side surface 25s may include a curved surface facing the light receiving side and a curved surface facing the emission side from a position about half the thickness of the diffusion sheet 25 (that is, the side surface 25s is a curved surface that does not include any flat surface and diffuses. It is desirable that the sheet 25 tapers at a position about half the thickness of the sheet 25).

  In such a case, both the lower end P and the upper end Q of the side surface 25s are not curved edges but gentle curved surfaces. Therefore, in the case of a perspective view, the lower end P of the side surface 25s and further the side surface 25s are not clearly noticeable.

  In the above description, the side surface 25s of the diffusion sheet 25 is a curved surface that does not include a plane at all, as shown in FIGS. 3A to 3C. However, the side surface 25s may be a curved surface including a plane.

  For example, as shown in FIG. 4A, the edge of the light receiving surface 25i in the diffusion sheet 25, specifically, only the joint between the side surface 25s and the light receiving surface 25i in the diffusion sheet 25 may be a curved surface (R shape). (However, the center of curvature of the curved surface is located on the diffusion sheet 25 side of the curved surface).

  In this way, only the lower end (joint) P of the side surface 25s of the diffusion sheet 25 is locally curved. That is, the most noticeable part in the case of strabismus is not an edge but a curved surface. Therefore, the end P of the light receiving surface 25i of the diffusion sheet 25 is not conspicuous.

  As shown in FIG. 4B, the edge of the exit surface 25o of the diffusion sheet 25, specifically, the joint between the side surface 25s and the exit surface 25o of the diffusion sheet 25 may be only a curved surface (R shape) ( However, the center of curvature of the curved surface is located on the diffusion sheet 25 side of the curved surface as in the joint between the side surface 25s and the light receiving surface 25i).

  With this configuration, only the upper end (joint) Q of the side surface 25s of the diffusion sheet 25 is locally curved. Then, in the vicinity of the upper end Q of the side surface 25s, light travels in a complicated manner due to the curved surface, and the lower end P of the side surface 25s becomes inconspicuous because the light is visually recognized.

  As shown in FIG. 4C, the edge of the light receiving surface 25i and the edge of the emission surface 25o in the diffusion sheet 25, that is, the lower end P and the upper end Q of the side surface 25s may be curved. In this case, the lower end P of the side surface 25s becomes noticeable by being curved, and the lower end P of the side surface 25s is surely inconspicuous due to the light traveling near the upper end Q of the side surface 25s.

[Other embodiments]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, as described in the first embodiment, at least the end P of the light receiving surface 25i of the diffusion sheet 25 is black BK, and as described in the second embodiment, the edge of the diffusion sheet 25 is tapered. May be used in combination. That is, the edge of the diffusion sheet 25 may be tapered, and at least the end P of the light receiving surface 25i of the diffusion sheet 25 may be black BK.

  For example, as shown in FIG. 5A, in the diffusion sheet 25, the end P of the light receiving surface 25i is positioned inside the end Q of the exit surface 25o, so that the curved side surface 25s faces the light receiving side, and the curved surface The side surface 25s may be black BK.

  In this way, the degree of edge at the lower end P of the side surface 25s is lowered, and the side surface 25s including the lower end P is assimilated with the built-in chassis 41. Therefore, in the case of a perspective view, the lower end P of the side surface 25s is not clearly noticeable due to its own shape and black BK.

  Further, as shown in FIG. 5B, in the diffusion sheet 25, the end surface Q of the exit surface 25o is positioned inside the end P of the light receiving surface, so that the curved side surface 25s faces the exit side, and the curved surface The side surface 25s may be black BK.

  In this case, the black BK side surface 25s, which is a gentle curved surface, is assimilated with the built-in chassis 41 before the lower end P of the side surface 25s is seen, and therefore the lower end P of the side surface 25s becomes inconspicuous.

  Further, as shown in FIG. 5C, even in the diffusion sheet 25, the side surface 25s may be a curved surface including a portion inclined toward the black BK light-receiving side and a portion inclined toward the black BK emission side. Good. In short, the edge of the diffusion sheet 25 may be tapered and black BK.

  In this way, both the lower end P and the upper end Q of the side surface 25s become gentle black BK curved surfaces instead of edges. That is, the entire side surface 25s is rounded black. Therefore, the side surface 25s is surely inconspicuous in a perspective view with its own shape and black BK.

  5A to 5C described above, the black BK portion is the entire curved side surface 25s (from the end of the light receiving surface 25i to the end of the exit surface 25o), but is not limited thereto. It is not a thing. In short, a part of the side surface 25s of the diffusion sheet 25, more specifically, the end P of the light receiving surface 25i of the diffusion sheet 25 may be black BK.

  Further, the side surface 25s is a curved surface including a flat surface and may include a black BK portion. For example, as shown in FIG. 6A, the joint between the side surface 25s and the light receiving surface 25i of the diffusion sheet 25 may be a black BK curved surface (R shape).

  In this case, the lower end P of the side surface 25s that is most conspicuous in the case of perspective is a curved surface of black BK. Therefore, the end P of the light receiving surface 25i of the diffusion sheet 25 is not clearly noticeable.

  6B, in the diffusion sheet 25, the side surface 25s, the edge of the light receiving surface 25i (the lower end P of the side surface 25s), and the edge of the emission surface 25o (the upper end Q of the side surface 25s) are black BK. The joint (upper end Q) between the side surface 25s and the emission surface 25o may be a curved surface.

  In this case, since the end P of the light receiving surface 25i is black BK, the black BK portion is assimilated with the built-in chassis 41 and is not easily seen in perspective. In addition, since the entire side surface 25s (the lower end P and the upper end Q of the side surface 25s) is black BK, even the side surface 25s is not easily seen in perspective. Further, the light that has not been absorbed by the black BK near the upper end Q of the side surface 25s travels in a complicated manner due to the curved surface. Therefore, the lower end P of the side surface 25s becomes less noticeable when the light is visually recognized.

  Further, as shown in FIG. 6C, the edge of the light receiving surface 25i and the edge of the emission surface 25o in the diffusion sheet 25 may be a curved surface of black BK. In this way, the lower end P of the side surface 25s becomes a black BK curved surface and becomes noticeable, and is assimilated with the black built-in chassis 41. In addition, since the upper end Q of the side surface 25s is also black BK, that portion is assimilated into the built-in chassis 41. In addition, the light that has not been absorbed by the black BK near the upper end Q of the side surface 25s travels in a complicated manner due to the curved surface, making it difficult to see the lower end P of the side surface 25s. Therefore, the lower end P of the side surface 25s is surely inconspicuous.

  6A to 6C described above, the black BK portion is necessary for the lower end P of the side surface 25s, but the other portions are not essential. Accordingly, the entire side surface 25s may be black BK, or the upper end Q of the side surface 25s in FIG. 6B may be other than black. Further, the edge of the emission surface 25o in FIG. 6C may be a curved surface with a color other than black BK. In short, it is only necessary that the edge of the light receiving surface 25i of the diffusion sheet 25 is black BK.

  5A to 5C and FIGS. 6A to 6C, as described above, when the built-in chassis 41 is black, the black BK portion and the built-in chassis 41 are assimilated, so that the user More difficult to see. Of course, if the pattern of the black mask BM located at the edge of the liquid crystal display panel 11 is seen in the perspective view, the end P of the light receiving surface 25i of the diffusion sheet 25 becomes more inconspicuous.

  In the above, the diffusion sheet 25 has been described as an example, but the black BK portion and the curved surface portion may exist in addition to the diffusion sheet 25. For example, it may be on the edge of the lens sheet 26 or the edge of the reflection sheet 24.

  Finally, it goes without saying that embodiments obtained by appropriately combining the techniques disclosed above are also included in the technical scope of the present invention.

FIG. 8 is a cross-sectional view taken along line A-A ′ of the liquid crystal display device shown in FIG. 7. FIG. 8 is a cross-sectional view taken along line B-B ′ of the liquid crystal display device shown in FIG. 7. (A) is a partially enlarged view showing a state in which the side surface of the diffusion sheet is inclined toward the light receiving side, and (B) is a partially enlarged view showing a state in which the side surface of the diffusion sheet is inclined toward the emission side. FIG. 6C is a partially enlarged view showing a state in which a part of the side surface of the diffusion sheet is inclined toward the light receiving side and the remaining part is inclined toward the emission side. (A) is a partially enlarged view showing that the end of the light receiving surface of the diffusion sheet is a curved surface, (B) is a partially enlarged view showing that the end of the exit surface of the diffusion sheet is a curved surface, (C) is the elements on larger scale which show that the edge of the light-receiving surface of a diffusion sheet and the output surface is a curved surface. (A) is a partially enlarged view showing a state where the black side surface of the diffusion sheet is inclined toward the light receiving side, and (B) is a state where the black and white side surface of the diffusion sheet is inclined toward the emission side. (C) is a partially enlarged view showing a state in which a part of the black side surface of the diffusion sheet is inclined toward the light receiving side and the remaining black portion is inclined toward the emitting side. (A) is a partially enlarged view showing that the end of the light receiving surface of the diffusion sheet is a black curved surface, and (B) is a partially enlarged view showing that the end of the exit surface of the diffusion sheet is a black curved surface. It is a figure and (C) is the elements on larger scale which show that the edge of the light-receiving surface of a diffusion sheet and an output surface is a black curved surface. FIG. 3 is an exploded perspective view of a liquid crystal display device. These are side surface sectional drawings of the conventional liquid crystal display device.

Explanation of symbols

11 Liquid crystal display panel 21 Backlight unit 22 Fluorescent tube (light source)
23 Lamp holder (first support)
23u Top surface of lamp holder 24 Reflective sheet 25 Diffusion sheet (optical sheet)
25i Light receiving surface of diffusion sheet P End of light receiving surface of diffusion sheet (edge of diffusion sheet, lower end of side surface of diffusion sheet)
25o Exit surface of diffusion sheet Q End of exit surface of diffusion sheet (edge of diffusion sheet, upper end of side surface of diffusion sheet)
25s Side surface of diffusion sheet 26 Optical sheet (optical sheet)
31 Backlight chassis (first support)
41 Built-in chassis (second support)
51 Bezel 89 Liquid crystal display device

Claims (16)

A light source that emits light;
An optical sheet that receives and emits light from the light source, and at least an end of a light receiving surface of the sheet is black;
A first support for supporting an edge of the optical sheet;
A black second support that sandwiches an edge of the optical sheet with the first support;
Including backlight unit. A light source that emits light;
A sheet that receives and emits light from the light source, and includes an optical sheet that has a tapered edge by including a curved surface in a part of the edge of the sheet; and
A first support for supporting an edge of the optical sheet;
Including backlight unit. A light source that emits light;
A sheet that receives and emits light from the light source, and includes a curved surface at a part of the edge of the sheet, resulting in a tapered edge and at least the edge of the light receiving surface of the sheet is black. An optical sheet;
A first support for supporting an edge of the optical sheet;
A black second support that sandwiches an edge of the optical sheet with the first support;
Including backlight unit.   The backlight unit according to claim 1 or 3, wherein an end of an emission surface of the optical sheet is black.   The backlight unit according to claim 4, wherein a side surface of the optical sheet from the end of the light receiving surface to the end of the emission surface is black.   The backlight unit according to claim 1, wherein the black portion of the optical sheet is formed by painting.   The backlight unit according to claim 1, wherein a black portion of the optical sheet is formed by chemical treatment.   The backlight unit according to claim 1, wherein a black portion of the optical sheet is formed by applying a black seal. By making the side surface of the optical sheet a curved surface, the edge of the optical sheet is tapered,
9. The backlight unit according to claim 2, wherein the center of curvature of the curved surface is located on the optical sheet side with the curved surface as a boundary, or the backlight unit according to claim 4 that cites claim 2 or 3. With the optical sheet as a boundary, the side where the light receiving surface of the optical sheet is positioned as the light receiving side
10. The backlight unit according to claim 9, wherein a side surface of the curved surface of the optical sheet is inclined toward the light receiving side when the end of the light receiving surface is positioned inside the end of the light emitting surface of the optical sheet. With the optical sheet as a boundary, when the side where the emission surface of the optical sheet is located is the emission side,
10. The backlight unit according to claim 9, wherein a side surface of the curved surface of the optical sheet is inclined toward the emission side when the end of the emission surface is located inside the end of the light receiving surface of the optical sheet. At least one of the joint between the side surface and the light receiving surface in the optical sheet, and the joint between the side surface and the emission surface in the optical sheet is a curved surface, the edge of the optical sheet is tapered,
9. The backlight unit according to claim 2, wherein the center of curvature of the curved surface is located on the optical sheet side with the curved surface as a boundary, or the backlight unit according to claim 4 that cites claim 2 or 3. The first support is at least one of a backlight chassis that houses the light source and a light source holder that supports the light source,
The built-in chassis that sandwiches the edge of the optical sheet with the backlight chassis is the second support body. 13. The backlight unit described in. The first edge portion facing at the edge of the optical sheet is supported by a backlight chassis that houses the light source as the first support,
The second edge portion of the optical sheet other than the first edge portion is supported by a light source holder that supports the light source as the first support,
The built-in chassis that sandwiches the edge of the optical sheet with the backlight chassis is the second support body. 13. The backlight unit described in. The backlight unit according to any one of claims 1 to 14,
A liquid crystal display panel positioned so as to cover the optical sheet in order to receive light emitted from the backlight unit;
Including a liquid crystal display device.   The liquid crystal display device according to claim 15, wherein a black light-shielding mask pattern is included at an edge of the liquid crystal display panel.

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