JP2009181924A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suitable technique capable of lessening uneven luminance while alleviating attenuation of the luminance on both ends in a longitudinal direction of a light source in a liquid crystal display. <P>SOLUTION: The liquid crystal display includes a liquid crystal panel (5), a plurality of linear light sources (3) arranged at the back side of the liquid crystal panel in order to illuminate light to the liquid crystal panel, and a frame (2) with a box-shape arranged at the back side of the linear light source. The linear light source (3) is arranged at the side-face (2c) side of the frame in the horizontal direction of the liquid crystal panel (5) as a longitudinal direction, a concave dent (2c1) is arranged on the periphery of a section where the linear light source of a reflecting section (2c0) arranged on a side face of the frame is prepared, and the reflecting section having a curved surface is formed with the concave dent (2c1) on the periphery of a section where the linear light source (3) is arranged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly, to a direct type backlight unit used in a liquid crystal display device and a liquid crystal display device including the same.

  As a liquid crystal panel used for a liquid crystal display device, a simple matrix type and an active matrix type using a TFT (Thin Film Transistor) are known. However, since such a liquid crystal panel is not a self-luminous type, a separate illumination light source is necessary to visualize an image formed on the liquid crystal panel.

  Accordingly, the liquid crystal display device includes a liquid crystal display panel in which a drain driver and a gate driver are arranged in the periphery, and a backlight unit that irradiates the liquid crystal display panel (hereinafter, the backlight unit is referred to as BLU).

  The BLU includes a side light type BLU and a direct type BLU. In recent years, liquid crystal display devices have become larger and have larger screens. In such large-sized and large-screen liquid crystal display devices, direct type BLUs that provide high brightness are suitable. Note that liquid crystal display devices that employ a direct-type BLU are described in, for example, Patent Document 1 and Patent Document 2.

JP 2006-259750 A Japanese Patent Laid-Open No. 11-084377

  The direct type BLU has one or a plurality of linear light sources (for example, cold cathode fluorescent lamps), an optical member including a diffuser plate on which light emitted from the linear light sources is incident, and a linear light source. A reflector (reflecting member) having a reflecting surface that reflects light irradiated to the side opposite to the liquid crystal display panel to the liquid crystal display panel side is provided.

  In recent years, there is an increasing demand for thinning a liquid crystal display device having a large screen. However, in order to reduce the thickness of a large-screen liquid crystal display device, it is necessary to reduce the thickness of the direct type BLU. When the direct type BLU is thinned, that is, when the distance between the optical member and the reflector is shortened, there is a problem that the luminance distribution becomes nonuniform on the display surface of the liquid crystal display panel. The non-uniform luminance distribution is particularly noticeable on the end face of the liquid crystal display panel, and a decrease in luminance on both end faces in the longitudinal direction of the linear light source has become a problem.

  Such non-uniform luminance distribution is particularly noticeable on the end face of a liquid crystal display panel, and a decrease in luminance at both end faces in the longitudinal direction of a linear light source (for example, EEFL (External Electrode Fluorescent Lamp)) has become a problem. Yes. In addition, when the electrode portions located at both ends or one end in the longitudinal direction of the linear light source are within the effective range of the BLU, the electrode does not emit light, so that it appears as a dark portion, resulting in luminance unevenness. It was.

  The present invention has been made in view of the above. The present invention provides a technique suitable for reducing luminance unevenness while reducing attenuation of luminance at both ends in the longitudinal direction of the light source.

  The present invention is characterized by the structures described in the claims. That is, the present invention relates to a liquid crystal panel, a plurality of linear light sources disposed on the back side of the liquid crystal panel for irradiating the liquid crystal panel, and a bowl-shaped light source disposed on the back side of the linear light source. A reflective frame for reflecting the light from the linear light source and irradiating the liquid crystal panel on the inner wall surface of the frame, and the linear light source includes the liquid crystal panel. Is provided on the side surface side of the frame with the horizontal direction as the longitudinal direction, and a recess is provided around a portion of the reflective portion provided on the side surface of the frame where the linear light source is provided, and the line A reflection part having a curved surface is formed around a part where the light source is provided.

  The recess may have a semi-elliptical shape when the side surface of the frame is viewed from the display surface side of the liquid crystal panel. A cross section of the depression perpendicular to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel is a curved surface. In addition, in a cross section orthogonal to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel, an angle formed by a tangent to the curved surface of the depression and a straight line parallel to the horizontal direction of the liquid crystal panel is the position of the curved surface. It is preferable that it differs according to. This angle may be gradually increased from the bottom surface of the frame toward the liquid crystal panel.

  Moreover, you may provide a reflective element so that the electrode part of the said linear light source may be covered. The reflecting element may be one having a substantially arched cross section perpendicular to the display surface of the liquid crystal panel and parallel to the vertical direction of the liquid crystal panel. The upper surface of the arch-shaped reflective element may have a curved surface in a cross section orthogonal to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel.

  Furthermore, a chamfer may be applied to a boundary portion between the reflection portion on the side surface of the frame and the depression. In addition, the recess is provided corresponding to each of the plurality of linear light sources, and the shape of the boundary side where the plurality of recesses are adjacent to each other on the center side of the frame is the display surface side of the liquid crystal panel It may be linear or arcuate when viewed from the side.

  According to the present invention, in a thinned liquid crystal display device, it is possible to reduce the decrease in luminance of the liquid crystal display panel at both ends in the longitudinal direction of the linear light source and improve the light emission quality. In addition, the frame can be narrowed. The ambient illuminance ratio can be improved while maintaining the uneven brightness.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration example of a liquid crystal display device including a direct type backlight. FIG. 1A is a developed perspective view showing only the backlight, and FIG. 1B is a view perpendicular to a linear light source for explaining a state in which the backlight of FIG. 1A is incorporated in a liquid crystal panel. FIG. 1C is a partial sectional view showing a partial sectional view in a direction parallel to the linear light source of FIG.

  As shown in FIG. 1A, a direct type backlight 1 includes a frame 2 having side walls 2b and 2c rising from a pair of opposing parallel edges of a rectangular bottom plate 2a in a liquid crystal panel direction, and the frame 2 A linear light source 3 attached to extend in a direction parallel to one of the pair of side walls 2b at the inner bottom of the bottom plate 2a, and a light diffusion plate 4 interposed between the linear light source 3 and the liquid crystal panel. I have. Thus, the frame 2 according to the present embodiment has a bowl shape or a box shape.

  The linear light source 3 is, for example, a cold cathode fluorescent lamp. In FIG. 1A, the two linear light sources 3 are installed along the bottom surface 2a in parallel with the other side walls 2b so that the two are hung on the side walls 2c.

  A state in which the backlight 1 is installed on the back surface of the liquid crystal panel 5 is shown in FIGS. The liquid crystal panel 5 is configured by sandwiching a liquid crystal layer 5e between two transparent substrates (glass plates) 5a and 5b and laminating polarizing plates 5c and 5d on the upper surface thereof. The liquid crystal panel may be either a simple matrix type or an active matrix type, and other light compensation films and the like may be laminated depending on the type. The direction of the arrow A indicates the effective display area of the liquid crystal panel 5 of the liquid crystal display device.

  As shown in FIG. 1B, at least the inner surface of the linear light source 3 and the bottom plate 2a of the frame 2 and the side wall 2b parallel to the longitudinal direction of the linear light source 3 is a reflective surface. Is reflected in the direction of the liquid crystal panel 5 to efficiently use the light.

  On the other hand, as shown in FIG. 1C, the linear light source 3 has electrodes 3a for applying a voltage at both ends, and no light is emitted from the electrode 3a. Accordingly, it is inevitable that the luminance of the end portion of the liquid crystal panel is reduced to some extent as compared with the central portion. However, the effective display area of the liquid crystal display panel 5 is within the range of the arrow A. That is, the effective display area extends up to the upper part of the electrode 3. If the electrode 3a is arranged outside the effective display area, this problem may be solved. However, in recent years, in addition to thinning, there is an increasing demand for a narrower frame. As the liquid crystal display device becomes thinner and narrower, the electrode 3a must be disposed inside the effective display area.

  In order to cover this, at least the inner surface of the side wall 2c of the frame 2 perpendicular to the linear light source 3 has a reflective surface as in the case of FIG. The light from the light source 3 is reflected in the direction of the liquid crystal panel 5 to provide a reflector that efficiently uses the light.

  FIG. 2 is a diagram for explaining the luminance distribution near the end of the effective display area of the left side wall 2c of FIG. FIG. 2A is a schematic cross-sectional view showing the relative positions of the line light source 3 and its electrode 3a, and the left side wall 2c and the bottom plate 2a. FIG. 2B is a graph for explaining the qualitative relationship between the luminance levels of the liquid crystal panel 5 in the direction parallel to the line light source 3 of FIG. The horizontal axis is the position in the direction parallel to the linear light source 3 from the end d0 of the effective display area toward the inside of the effective display area, and the vertical axis is the luminance level. Moreover, FIG.2 (c) shows the relationship between an applicable position and the electrode 3a of the line light source 3 on the graph upper part for reference. Moreover, it is the schematic which shows that the left side wall 2c and the baseplate 2a are the reflectors which have the inclination by angle (theta). However, in the present invention, the side wall in the direction perpendicular to the linear light source is referred to as a reflector, and is distinguished from other reflecting surfaces.

  In the graph of FIG. 2B, it can be seen that the luminance level P decreases from the inside of the effective display area toward the end d0. That is, there is almost no decrease in the luminance P from the inside of the liquid crystal panel 5 to the electrode 3a, and the decrease in the luminance P becomes significant from the position d1 (luminance P1) of the electrode 3a, and the luminance P0 at the end d0 of the effective display area. It has become. In addition, if the side wall 2c does not have a reflecting function as a reflector, it has been found that the luminance P0 at the effective display region end d0 further decreases and becomes almost zero.

  As shown in FIG. 2, the side wall 2c has a tilt angle θ with respect to the bottom plate 2a and is a reflecting surface to constitute a reflector. In the effective display area above the electrode 3a portion where the line light source 3 does not emit light. Although we tried to reduce the brightness level, it is still not enough.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 3 is a view for explaining an embodiment of the reflector according to the present invention. The configuration is the same as that of FIG. 2, and the side wall 2c0 is different from the shape of the side wall 2c.

  In the embodiment of FIG. 3, the reflecting surface of the side wall 2c0 is a reflector having at least two or more different inclination angles, or a reflector having at least two or more reflecting surfaces.

  That is, as shown in the side wall 2c0 of FIG. 3 (a) or (c), the reflector of the embodiment of FIG. 3 has at least two different inclination angles or has at least two inclined surfaces. The inclined surfaces are the two inclined surfaces f1 and f2 that constitute the reflector of the side wall 2c0 shown in FIG. For example, there are three inclined surfaces, of which two upper and lower surfaces have the same inclination angle, and one of the inner surfaces is a reflector different in configuration from the upper and lower surfaces. The broken line portion in FIG. 3 (b) is a reproduction of the luminance level shown in FIG. 2, and the solid line portion is the luminance level in the configuration of FIG. 3 (a) or FIG. 3 (c). According to the present embodiment, as shown in FIG. 3B, the luminance level at the effective display region end d0 increases to P0 '.

  In the embodiment of FIG. 3, the height at which the tilt angle of the reflector changes is lower than the axial center 3x of the line light source 3. However, there are cases where the axial center 3x of the line light source 3 is higher than this. Further, the height above the tube or the height below the tube may be used as a reference in consideration of the tube diameter of the linear light source 3 without using the height of the axial center 3x as a reference. In any case, the boundary between the bottom plate 2a and the side wall 2c0 is inside the electrode 3a.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a view for explaining an embodiment of the reflector of the present invention.

  FIG. 4 is a diagram simply showing the shape of the bottom plate 2a and the reflector of the present invention from the lateral direction, similarly to FIG. 2 (c) or FIG. 3 (c). The alternate long and short dash line is the center 3x of the line light source 3.

FIG. 4 shows a cross section of the reflector perpendicular to the display surface of the liquid crystal panel 5 and parallel to the horizontal direction of the liquid crystal panel (in other words, the longitudinal direction of the light source 3). The reflector (side wall) of FIG. 4 is an embodiment having four inclined surfaces. Further, the inclined surfaces h1 to h4 are formed by curved lines (not shown), for example, strings inscribed by parabolas. Accordingly, the inclination angles of the inclined surfaces h1 to h4,..., Hn (that is, the angle formed between the inclined surface and a straight line parallel to the display surface of the liquid crystal panel 5) have the following relationship. That is,
θh1 <θh2 <θh3 <θh4 <... <θhn (1)
It is.

If the number of inclined surfaces is infinite, a curve is obtained. Accordingly, the inclined surface constituting the side wall (reflector) of the present invention includes a curved line. In addition, curves such as parabola are upside down, and the relationship between the tilt angles is
θh1>θh2>θh3>θh4>...> θhn Equation (2)
(See FIG. 5). In this case, it is constituted by a string circumscribing a curve such as a parabola.

  Further, it is not necessary to use one curve as a base, and a plurality of curves having the same or different forms may be used.

  Moreover, you may process so that it may become smooth, such as taking the edge of the corner part of the junction part of each inclined surface, and comprising with a curve.

  Further, the curved line may be divided at a predetermined ratio to form stepped side walls. In addition, although the division | segmentation structure of an inclined surface may be equal in both a height direction and a horizontal direction, it is normal that it differs. For example, when the angle between the tangent line of the curve and the bottom plate 2a is small, the division ratio may be increased.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 5 is a view for explaining an embodiment of the reflector of the present invention.

FIG. 5 is a diagram simply showing the shape of the bottom plate 2a and the reflector of the present invention from the lateral direction, similarly to FIG. 2 (c) or FIG. 3 (c). The alternate long and short dash line is the center 3x of the line light source 3. FIG. 5 shows an embodiment in which curves such as parabola are upside down with respect to FIG. That is, the relationship between the tilt angles is
θm1>θm2>θm3>θm4>...> θmn... Equation (3)
It is.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a view for explaining an embodiment of the reflector of the present invention.

  FIG. 6 is a diagram simply showing the shape of the bottom plate 2a and the reflector of the present invention from the lateral direction, similarly to FIG. 2 (c) or FIG. 3 (c).

As shown in FIG. 6, in the case of a reflector having three or more inclined surfaces, the inclined surfaces q0,..., Qk, qk + 1, qk + 2,. ..., Qn (n and k are natural numbers, 0 ≦ k <n), there is the following relationship. That is,
θk <θk + 1 and θk + 1> θk + 2 (4)
Or
θk> θk + 1 and θk + 1 <θk + 2 (5)
That is, in the embodiment of FIG. 4 or FIG. 5, the inclination angle of the reflecting surface constituting the reflector is either simply increased or simply decreased as it goes upward.

  However, as in the embodiment of FIG. 6, the inclination angles of the reflecting surfaces constituting the reflector are not simply reduced gradually or increased gradually, but are combined with irregular inclination angles. Therefore, the reflector is uneven.

  Moreover, you may process so that it may become smooth, such as taking the edge of the uneven | corrugated | grooved part of the connection part of each reflective surface, and comprising with a curve.

  Furthermore, other embodiments of the present invention will be described below. Each of the above-described embodiments is a reflector constituted by a plurality of inclined angles or a plurality of inclined reflecting surfaces with respect to the longitudinal direction of the linear light source. However, in another embodiment of the present invention, the shape of the side surface of the linear light source is inclined.

  FIG. 7 is a diagram showing a reflector portion of the above-described embodiment of FIG. 4 as viewed from above. For convenience of explanation, the liquid crystal panel portion is omitted for convenience. Further, only the two linear light sources and the left end are shown.

  FIG. 7 is a schematic view of the reflector shape shown in FIG. 4 as viewed from above. The inclined surfaces h1 to h4 rise from the bottom plate 2a and reach the liquid crystal panel surface. H0 is a portion in contact with the frame portion (outside the effective display area) of the liquid crystal panel surface.

  Next, another embodiment of the present invention will be described with reference to FIGS. 8 and 9 are diagrams for explaining an embodiment of the reflector of the present invention.

  The embodiment shown in FIGS. 8 and 9 reflects in the direction perpendicular to the longitudinal direction of the linear light source, whereas the embodiment described above has a reflector structure that is inclined so as to reflect in the longitudinal direction of the linear light source. It is so inclined.

  In FIG. 8, a triangular pyramid reflector is provided on the side wall 2c in parallel between two linear light sources 3 arranged in parallel. In FIG. 8, for convenience, the two linear light sources, the bottom plate 2a, and the reflector b1 are shown only halfway.

  Moreover, the number of the linear light sources 3 and the number of the reflectors b1 can be provided arbitrarily. Further, the length of the reflector b1 may be up to the other end (not shown) or may be halfway.

  FIG. 9 shows a reflector structure in which, for example, the inclined surface of the embodiment of FIG. 4 is further inclined in a direction parallel to the linear light source 3.

  By providing such an inclination, light from the light source is efficiently reflected not only in the longitudinal direction of the linear light source but also in the direction perpendicular to the longitudinal direction of the linear light source. Level further increases.

  In FIG. 9, only one linear light source is drawn so that the structure of the reflector b <b> 2 can be easily understood, but it goes without saying that a similar linear light source 3 exists on the left side. Similarly, the linear light source 3 and the bottom plate 2a are shown only halfway.

  Moreover, the number of the linear light sources 3 and the number of the reflectors b2 can be arbitrarily provided. Further, the length of the reflector b2 may be up to the other end (not shown) or may be halfway.

  As described above, according to the embodiment shown in FIGS. 4 to 9, the luminance level on the end side of the effective display area is close to the internal luminance level, so that the decrease in luminance at the end portion of the liquid crystal panel is reduced. be able to.

  That is, in the thinned liquid crystal display device, it is possible to reduce the decrease in luminance of the liquid crystal display panel at both ends in the longitudinal direction of the linear light source and to improve the light emission quality. Furthermore, it is possible to narrow the frame.

  In the embodiment described above, the shape of the reflector is the same for all the liquid crystal panels. However, the central portion and both end portions of the liquid crystal panel may have different shapes with respect to the direction perpendicular to the axial direction of the linear light source. Further, the shape of the reflector may be changed alternately or in a predetermined order.

  Further, in the above-described embodiment, the reflecting surface of the reflector is usually subjected to a mirror finish or a surface treatment so as to have a gloss in order to increase the reflection efficiency. However, the brightness level distribution of the liquid crystal panel may be made more uniform by roughening the surface with means such as a blaster and diffusing the light with light reflection. In that case, after the surface is roughened, a reflective film may be formed to increase the reflectance.

  As mentioned above, although this invention was demonstrated by the Example, these embodiment is an Example of this invention, Comprising: This invention is not limited only to these embodiment. The present invention is not limited to the embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention as long as it has ordinary knowledge in the technical field to which the present invention belongs.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 10 is a view of an embodiment of the reflector of the present invention as viewed from the irradiation surface side of the backlight unit (that is, the display surface side of the liquid crystal panel 5). In this embodiment, the reflecting portion 2c0 is a reflecting portion provided on the side surface 2c of the frame 2, and a recess 2C1 is formed in the reflecting portion 2c0. The recess 2c1 is formed around a portion of the reflection portion 2c0 provided on the side surface 2c of the frame 2 where the electrode portion 3a of the linear light source 3 is provided. In the present embodiment, a depression 2c1 (hereinafter referred to as a depression-like reflecting portion) is provided corresponding to each of the plurality of linear light sources 3. As is clear from FIG. 10, the hollow reflecting portion 2 c 1 has a semi-elliptical shape when viewed from the display surface side of the liquid crystal panel 5. In other words, in this embodiment, the reflection portion 2c0 provided on the side surface 2c of the frame 2 is curved three-dimensionally around the position where the electrode portion 3a of the linear light source 3 is disposed.

  The concave reflecting portion 2c1 can have a substantially condensing effect around the electrode portion 3a due to its curved shape. The shape of the recess 2c1 may be, for example, a spheroid, a paraboloid, or a cylindrical shape. Moreover, you may approximate the shape which combined these two or more with several planes. The light emitted from the light source 3 is incident on the concave reflecting portion 2c1 and is collected around the electrode portion 3a, thereby preventing the luminance level from being lowered at the electrode portion 3a.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 11 is a diagram showing an embodiment of the reflector of the present invention. FIG. 11A is a view seen from the irradiation surface side of the backlight unit (that is, the display surface side of the liquid crystal panel 5). FIG. 11 b is a view as seen from the side of the backlight unit. In the central axis of the linear light source 3, the reflector is perpendicular to the display surface of the liquid crystal panel 5 and in the horizontal direction of the liquid crystal panel (the longitudinal direction of the linear light source 3). Direction). In this embodiment, a convex reflection element 2c2 provided on the upper side of the electrode portion 3a of the light source 3 is added to the embodiment shown in FIG. The convex reflective element 2c2 is provided at a position corresponding to the upper part of the electrode portion 3a of the light source 3 in the concave reflective portion 2c1, and has a convex shape in the direction of the liquid crystal panel 5.

  The convex reflective element 2C2 can have an effect of reflecting light to the irradiation surface around the electrode portion 3a and restoring the luminance level around the electrode portion 3a. The shape of the convex reflection element 2c2 is configured by, for example, at least one plane or at least one curved surface. The shape may be inclined from the bottom 2 or may be a curved surface having an inflection point. Further, the convex reflection element 2c2 may have a thickness of 0.3 mm or more in order to maintain the strength. By providing a gap of 0.2 mm or more between the electrode portion 3a and the reflecting means 2c2, it is possible to prevent the light source 3 and the convex reflecting element 2c2 from colliding when the backlight unit vibrates. Damage to 2c1 can be prevented. The convex reflection element 2c2 can reflect the light emitted from the light source 3 to the upper part of the electrode part 3a, and can prevent the luminance level from being lowered by the electrode part 3a.

  Next, still another embodiment of the present invention will be described with reference to FIG. FIG. 12 is a view of one embodiment of the reflector of the present invention as seen from the side of the backlight unit. The reflector is perpendicular to the display surface of the liquid crystal panel 5 on the central axis of the linear light source 3 and is the liquid crystal panel. A cross section parallel to the horizontal direction (longitudinal direction of the linear light source 3) is shown. Further, FIG. 12c shows a cross section perpendicular to the display surface of the liquid crystal panel 5 and parallel to the vertical direction of the liquid crystal panel (direction perpendicular to the longitudinal direction of the linear light source 3). In this embodiment, the reflective part 2c0 is provided with an arch-like reflective element 2cA so as to cover the electrode part 3a of the light source 3 of the concave reflective part 2C1. As is apparent from FIG. 12 c, the arch-shaped reflective element 2 c </ b> A has an arched or trapezoidal cross-sectional shape that is orthogonal to the display surface of the liquid crystal panel 5 and parallel to the vertical direction of the liquid crystal panel. The trapezoidal reflective element 2cA includes an upper surface 2cA1 and a side surface 2cA2.

  The arch-shaped reflective element 2cA can reflect the light incident from the side of the electrode part to the irradiation surface, and can have an effect of restoring the luminance level around the electrode part 3a. The arch-shaped reflecting element 2cA can reflect the light beam emitted from the light source 3 and incident on the electrode portion 3a to the upper portion around the electrode portion 3a, thereby preventing the brightness level from decreasing around the electrode portion 3a. it can. In order to prevent a decrease in luminance at both ends of the backlight unit, it is necessary to set the inclination of the reflecting portion 2c0 between approximately 30 degrees and 80 degrees. However, when the inclination is made steep, there is a problem that the electrode portion 3a is visible. Conventionally, in order to prevent the electrodes from entering the effective display area, measures such as lengthening the light source 3 have been taken, but there has been a problem that the size of the backlight unit becomes large. According to the present embodiment, when the thickness of the backlight is 10 mm or more, evenness of the brightness can be maintained even if the electrode 3a is exposed about 3 mm from the arch-shaped reflective element 2cA.

  Further, as shown in FIG. 12B, the trapezoidal reflective element 2cA has an upper surface 2cA1 having a curved surface in a cross section orthogonal to the display surface of the liquid crystal panel 5 and parallel to the horizontal direction of the liquid crystal panel. In the present embodiment, the upper surface 2cA1 is shaped like an S-shape. Further, as shown in FIG. 12 c, the arch-shaped reflection element 2 c </ b> A has an arch shape or a trapezoidal shape, and the side surface 2 </ b> CA <b> 2 is inclined with respect to the bottom portion 2 a of the frame 2. Furthermore, the shape of the arch-shaped reflection element 2cA is configured by, for example, at least one plane or at least one curved surface.

  The arch-shaped reflecting element 2cA can prevent the light source 3 and the reflecting means 2c2 from colliding with each other when the backlight unit vibrates by setting the distance to the light source 3 to 0.2 mm or more. It is possible to prevent damage to the reflecting portion 2c0 and / or the recessed reflecting portion 2c1 on the side surface 2c. It is also possible to prevent interference due to thermal expansion of the reflecting portion 2c0 and / or the recessed reflecting portion 2c1. Furthermore, since the arched reflection element 2cA is inclined, it is possible to effectively reflect the incident light to the upper part of the electrode a, and it is possible to prevent the luminance level from being lowered at the electrode part 3a. .

  Next, still another embodiment of the present invention will be described with reference to FIG. FIG. 13 is a view of an embodiment of the reflector of the present invention as viewed from the irradiation surface side of the backlight unit. As shown in this figure, in this embodiment, the boundary 2cB between the reflection portion 2c0 and the depression-like reflection portion 2c1 on the frame side surface 2c and further the boundary portion 2cB between the adjacent depression-like reflection portions 2c1 are chamfered. Are formed, and these are smoothly connected. For example, the boundary may be smoothly connected by a part of a spherical surface, a cylindrical surface, or the like, or may be connected by another curved surface. You may provide in the range of about R0.3mm to about R5mm according to a place. However, this does not limit how to take R. When the boundary 2cB between the reflective part 2c0 and the concave reflective part 2c1 and the boundary 2cB between the adjacent concave reflective parts 2c1 are not smooth, the distribution of reflected light suddenly changes at these boundaries. It may be visible on the irradiated surface. Therefore, in this embodiment, by smoothly connecting these boundaries 2cB, it is possible to smoothly change the luminance on the irradiation surface, and to suppress the occurrence of a luminance unevenness pattern. Therefore, in this embodiment, the luminance uniformity can be improved when the image displayed on the display surface of the display panel 5 is visually confirmed.

  Next, still another embodiment of the present invention will be described with reference to FIG. FIG. 14 is a view of an embodiment of the reflector of the present invention as viewed from the irradiation surface side of the backlight unit, and is a diagram simply showing the shape of the reflector of the present embodiment. In the above-described embodiment, when adjacent concave reflection parts 2c1 cross each other, a sharp point may occur. When assembling the backlight, the reflecting portion 2c0 may be assembled by a human hand, so there is a risk of injury if there is a sharp shape. In the present embodiment, it is possible to ensure the safety of the operator by making the sharply cut portion into a shape cut off by a plane. In other words, in the present embodiment, the shape of the boundary side where the plurality of indented reflecting portions 2 c 1 are adjacent to each other on the center side of the frame 2 is a linear shape 2 c 4 when viewed from the display surface side of the liquid crystal panel 5. In the example of FIG. 14, the shape of the boundary portion is linear, but it may be formed in an arc shape with a convex toward the center side of the frame 2. Furthermore, the boundary portion may be chamfered and R may be provided.

  In the above-described embodiment, the shape of the hollow reflection portion 2c1, the arch-like reflection element 2cA, and the like is the same. However, the central portion and both end portions of the liquid crystal panel may have different shapes with respect to the direction perpendicular to the axial direction of the light source. Further, the shape of the reflector may be changed alternately or in a predetermined order.

  Further, in the above-described embodiment, the dent-like reflection portion 2c1, the arch-like reflection element 2cA, and the like are usually configured by a diffuse reflection sheet, a diffuse reflection paint, or the like in order to improve luminance uniformity. However, for example, the surface finish is made to be mirror-finished or glossy, or the surface is roughened by means such as blasting to diffuse the reflected light, further uniforming the brightness level distribution of the liquid crystal panel You may make it let it. In that case, after the surface is roughened, a reflective film may be formed to increase the reflectance.

The schematic diagram explaining the structural example of the liquid crystal display device provided with the direct type | mold backlight. The figure for demonstrating the luminance distribution near the effective display area edge part of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating one Example of the reflector of this invention. The figure for demonstrating another Example of the reflector of this invention. The figure for demonstrating another Example of the reflector of this invention. The figure for demonstrating another Example of the reflector of this invention. The figure for demonstrating another Example of the reflector of this invention. The figure for demonstrating another Example of the reflector of this invention.

Explanation of symbols

  1: Backlight, 2: Frame, 2a: Bottom plate of frame, 2b: Side wall of frame, 2c, 2c0: Side wall of frame, 3: Linear light source, 3a: Linear light source electrode, 3x: Axis center of linear light source 4: Light diffusion plate, 5: Liquid crystal panel, A: Effective display area.

Claims (17)

In liquid crystal display devices,
A liquid crystal panel; a plurality of linear light sources arranged on the back side of the liquid crystal panel for irradiating the liquid crystal panel; and a frame having a bowl-like shape arranged on the back side of the linear light source. Prepared,
The inner wall surface of the frame is provided with a reflecting portion for reflecting the light from the linear light source and irradiating the liquid crystal panel,
The linear light source is provided on the side surface side of the frame with the horizontal direction of the liquid crystal panel as a longitudinal direction, and is recessed around a portion of the reflective portion provided on the side surface of the frame where the linear light source is provided. And a recess having a curved surface is formed around a portion where the linear light source is provided.   2. The liquid crystal display device according to claim 1, wherein the recess has a semi-elliptical shape when the side surface of the frame is viewed from the display surface side of the liquid crystal panel.   2. The liquid crystal display device according to claim 1, wherein a cross section of the depression perpendicular to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel is a curved surface.   4. The liquid crystal display device according to claim 3, wherein a tangent line of the curved surface of the depression and a straight line parallel to the horizontal direction of the liquid crystal panel in a cross section orthogonal to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel. The liquid crystal display device is characterized in that the angle formed by is different depending on the position of the curved surface.   5. The liquid crystal display device according to claim 4, wherein the angle is gradually increased from the bottom surface of the frame toward the liquid crystal panel.   The liquid crystal display device according to claim 1, wherein a reflective element is provided in the recess so as to cover an electrode portion of the linear light source.   7. The liquid crystal display device according to claim 6, wherein the reflective element has a substantially arched cross section perpendicular to the display surface of the liquid crystal panel and parallel to the vertical direction of the liquid crystal panel. Display device.   7. The liquid crystal display device according to claim 6, wherein an upper surface of the arched reflective element has a curved surface in a cross section orthogonal to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel. Display device.   2. The liquid crystal display device according to claim 1, wherein a chamfer is applied to a boundary portion between a reflection portion and a recess on a side surface of the frame.   2. The liquid crystal display device according to claim 1, wherein the recess is provided corresponding to each of the plurality of linear light sources, and a shape of the boundary side of the plurality of recesses adjacent to each other on the center side of the frame. However, the liquid crystal display device is linear or arcuate when viewed from the display surface side of the liquid crystal panel. In the backlight unit for illuminating the liquid crystal panel,
A plurality of linear light sources that emit light and a light reflection unit that is disposed on the back side of the plurality of linear light sources and reflects the light from the plurality of linear light sources to irradiate the liquid crystal panel. And a frame with a bowl shape,
In a cross section orthogonal to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel, the side surface of the frame is inclined with respect to the bottom surface of the frame, and the reflective portion provided on the side surface of the frame is at least A backlight unit comprising two or more planes or a combination of a plane and a curved surface. In the backlight unit according to claim 11, electrode portions are provided at both ends or one end in the longitudinal direction of the linear light source, and the electrode portions of the linear light source are located on the side of the frame,
A backlight unit, wherein a recess or a condensing shape is formed around an electrode portion of the linear light source of a reflection portion provided on a side surface of the frame.   12. The backlight unit according to claim 11, wherein a reflective element is provided above the electrode portion of the linear light source so as to cover the electrode portion.   14. The backlight unit according to claim 13, wherein the reflecting element has a substantially arched cross section perpendicular to the display surface of the liquid crystal panel and parallel to the vertical direction of the liquid crystal panel. Backlight unit.   15. The backlight unit according to claim 14, wherein an upper surface of the arched reflective element has a curved surface in a cross section orthogonal to the display surface of the liquid crystal panel and parallel to the horizontal direction of the liquid crystal panel. Light unit.   The backlight unit according to claim 11, wherein a chamfer is applied to a boundary portion between the reflection portion and the depression on the side surface of the frame.   12. The liquid crystal display device according to claim 11, wherein the recess is provided corresponding to each of the plurality of linear light sources, and a shape on a frame center side of a boundary portion where the plurality of recesses are adjacent to each other. However, the backlight unit is linear or arcuate when viewed from the display surface side of the liquid crystal panel.

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