JP2010097736A - Plane light source and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim at weight saving and thinning of a plane light source as well as a liquid crystal display without using a light guide plate, as compared with a conventional direct type. <P>SOLUTION: The plane light source is provided with a reflecting plate with a top face as a reflecting face, a diffusion plate arranged above the reflecting plate for diffusing transmitting light, and a plurality of unit illuminating parts 6 structured of reflecting frame bodies 4 arranged on the reflecting plate each with an opening face directed upward and with an inner periphery face 4a as a reflecting face, and LED light sources 5 each arranged inside the reflecting frame body and irradiating light with a constant angle of divergence by letting a light-irradiating face opposed to the inner periphery face 4a of the reflecting frame body 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a planar light source for illuminating a liquid crystal display panel and the like and a liquid crystal display device.

Liquid crystal display devices for image display are widely used for large displays such as thin television devices and thin monitors. This liquid crystal display device uses a backlight unit that emits light from the back side of the liquid crystal display panel to increase the brightness of the display screen.
The backlight unit includes, for example, a light guide plate and a light source such as an LED disposed on a side end surface of the light guide plate, guides light from the light source, and emits the light from the entire main surface toward the liquid crystal display panel. There is something to let me. In addition, as another backlight unit, there is a direct type backlight that does not use a light guide plate, installs a plurality of LED light sources at a distance directly below the diffusion plate, and emits light from each LED to the diffusion plate directly above. is there.

  In recent years, with the increase in size of liquid crystal television devices, there has been a further demand for lighter and thinner devices. However, in a backlight unit using a light guide plate, a large light guide plate or a plurality of light guide plates are installed side by side. There is a problem that the weight is increased. On the other hand, the direct type backlight that does not use the light guide plate can be reduced in weight because of the absence of the light guide plate, but in order to eliminate color mixing and uneven brightness, the distance between the LED light source and the diffusion plate is reduced. It is necessary to set it long or to narrow the arrangement pitch of the LED light sources.

  That is, since the LED light source that is a point light source has directivity, the portion directly above the light emission direction of the LED light source becomes very bright, so-called hot spot, and uneven brightness occurs. Therefore, it is necessary to improve the luminance uniformity and color mixing. However, as the entire backlight becomes thicker, more LED light sources are required, resulting in high costs.

  Conventionally, for example, in Patent Document 1, a reflecting member that diffuses light from an LED light source to the light source side between a diffusion plate installed on the back of a display unit and an LED light source equipped with an optical lens, and the reflecting member There has been proposed a backlight device including a transmissive diffusing member that is disposed in the vicinity of the display and transmits light while diffusing light toward the display unit. That is, in this backlight device, the light of the central portion from the LED light source toward the diffusion plate is reflected by the reflecting member and prevented from directly entering the diffusion plate, and the light diffused by the transmission diffusing member is diffused. The intensity of the light input to the diffuser is made uniform.

JP 2006-310045 A (Claims, FIG. 1)

However, the following problems remain in the conventional technology.
That is, in the technique described in Patent Document 1, the light intensity is made uniform to some extent by adding a reflecting member and a transmissive diffusing member. However, since it is a direct type backlight, the diffusion plate, the LED light source, It is necessary to set a long distance, and a reflecting member and a transparent diffusing member must be installed between the diffusing plate and the LED light source, resulting in an inconvenience that the entire backlight becomes thick.

  The present invention has been made in view of the above-described problems, and provides a planar light source and a liquid crystal display device that can be reduced in weight without using a light guide plate and can be reduced in thickness as compared with a conventional direct type. The purpose is to provide.

  The present invention employs the following configuration in order to solve the above problems. That is, the planar light source of the present invention includes a reflecting plate whose upper surface is a reflecting surface, a diffusion plate that is installed above the reflecting plate and diffuses transmitted light, and an opening surface is directed upward on the reflecting plate. And a reflection frame having an inner peripheral surface as a reflection surface, and a fixed spread with the light emission surface facing the inner peripheral surface of the reflection frame body and inside or inside the reflection frame body And a plurality of unit illumination units each including an LED light source that emits light with a corner.

In this planar light source, a reflection frame body that is installed on a reflection plate and whose inner peripheral surface is a reflection surface, and is installed inside or inside the reflection frame body and light is incident on the inner peripheral surface of the reflection frame body. Since it has a plurality of unit illuminating units composed of an LED light source that emits light with a constant divergence angle facing the emission surface, most of the light emitted from the LED light source is an upper diffusion plate The surface shape corresponding to the range surrounded by the reflection frame by the light from the LED light source, which is a point light source, by being incident on the diffuser after being reflected by the inner peripheral surface of the reflection frame without being directly incident on the reflection frame Can be used as a surface light source.
In addition, a reflective frame is provided not around the LED light source, but around the LED light source, and the light emission direction of the LED light source is not on the diffuser plate side directly above, but on the inner peripheral surface side of the surrounding reflector frame. Can be set narrow, and the entire light unit can be made thinner.
Therefore, by using the reflection frame body, it is possible to reduce the weight compared to the conventional light guide plate method, and further by installing the LED light source so that light can be emitted toward the inner peripheral surface of the reflection frame body, Compared with the direct type backlight, the luminance unevenness can be reduced and the luminance uniformity can be improved, and the thickness can be reduced.

  Moreover, the planar light source of the present invention is characterized in that the reflective frame is formed of a white resin. That is, in this planar light source, since the reflective frame is formed of white resin, the inner peripheral surface can be made into a white surface having a reflection effect and a diffusion effect without performing a reflection process or the like.

  Moreover, the planar light source of the present invention is characterized in that the reflection frame has an eaves portion that covers a portion directly above the LED light source. That is, in this unit illumination part, since the reflection frame has an eaves part that covers the portion directly above the LED light source, light directed from the LED light source toward the diffuser plate directly above can be shielded by the eaves part, Hot spots can be further reduced.

  Further, in the planar light source of the present invention, the lower surface of the eaves portion is a downward inclined reflecting surface inclined toward the inner peripheral surface of the reflecting frame body facing the light emitting surface of the LED light source. Features. That is, in this planar light source, the lower surface of the eaves portion is a downwardly inclined reflecting surface inclined toward the inner peripheral surface of the reflecting frame facing the light emitting surface of the LED light source. By reflecting the heading light toward the inner peripheral surface of the reflecting frame facing the lower surface of the eaves portion, the light shielded by the eaves portion can also contribute to the overall luminance.

  Further, the planar light source of the present invention is an upward inclined surface in which an inner peripheral surface facing the light emitting surface of the LED light source among the inner peripheral surfaces of the reflective frame body is inclined toward the opening surface side. It is characterized by being. That is, in this planar light source, the inner peripheral surface of the reflecting frame that faces the light emitting surface of the LED light source is an upward inclined surface that is inclined toward the opening surface side. The light can be further improved by reflecting the light from the light toward the diffusion plate disposed on the opening surface side.

  Moreover, the planar light source of the present invention is characterized in that there is a gap between the reflection frame and the diffusion plate. That is, in this planar light source, since the reflecting frame body is set apart from the diffusion plate and there is a gap between each other, light is emitted outside the reflecting frame body through the gap. The light passes between the bodies, and the boundary of the light shape corresponding to the reflecting frame irradiated on the irradiation surface of the diffusion plate becomes unclear. Therefore, by adjusting the gap between the reflection frame and the diffusion plate, the degree of light confinement in the reflection frame can be set, and the reflection frame reflected in the light shape irradiated on the irradiation surface of the diffusion plate It can be made inconspicuous between the outline of the light source and the adjacent reflecting frame.

  Moreover, the planar light source of the present invention is characterized in that the reflection frame body has a square shape or a rectangular shape, and the unit illumination units are arranged in a matrix shape including a plurality of columns and rows. That is, in this planar light source, the unit illumination unit having a reflective frame that is square or rectangular is arranged in a matrix composed of a plurality of columns and rows. So-called local dimming can be easily realized by the partial luminance control to be driven. For example, as local dimming, the backlight brightness is controlled according to the brightness and contrast of the image displayed on the liquid crystal display panel, and the backlight brightness is unit illuminated based on the image data input to the liquid crystal display panel. By adjusting the brightness by controlling the location and time for each part, it is possible to reduce the power consumption and improve the contrast, the moving image followability, and the like.

  Further, in the planar light source of the present invention, the reflection frame body is formed in a square frame shape or a rectangular frame shape, and the outer peripheral surface is also a reflection surface, and the unit illumination units bring the corners close to each other. LED light sources that are arranged in a zigzag state and emit light with a certain spread angle with the light emitting surface facing the outer peripheral surface of the reflecting frame body are installed between the adjacent unit illumination units. It is characterized by. That is, in this planar light source, the outer peripheral surface of the reflecting frame is also a reflecting surface, and the outer peripheral surface of the reflecting frame is placed between the plurality of unit illumination units arranged in a staggered manner with the corners close to each other. Since the LED light source with the light emitting surfaces facing each other is installed, the emitted light from the LED light source surrounded by the outer peripheral surface of the reflecting frame body in the region between the adjacent unit illumination units is the outer peripheral surface. By being reflected, light can be emitted toward the diffusion plate even in this region. Therefore, by alternately arranging every other reflection frame, the number of reflection frames to be installed side by side is halved as a whole, and the member cost can be reduced.

  Moreover, the planar light source of the present invention is characterized in that a plurality of the reflective frame bodies are integrated with a grid frame body constituted by a plurality of strip-shaped members assembled in a grid pattern. That is, in this planar light source, a plurality of reflecting frame bodies are integrated as a grid frame body composed of a plurality of strip-shaped members assembled in a grid pattern, so that the reflecting frame bodies are continuously matrixed. It is possible to easily produce a plurality of grid-like frame bodies arranged in the shape of a plurality of strip-like members, and to reduce the member cost, the number of mounting steps, and the like as compared with the case where the reflection frame bodies of individual members are arranged.

  Furthermore, in the planar light source of the present invention, at least one of the strip-shaped members intersecting each other is formed with a notch inclined at a predetermined angle with respect to the extending direction, and the other is inserted into the notch and assembled in a lattice shape. It is characterized by. That is, in this planar light source, at least one of the strip-shaped members intersecting each other is formed with a notch inclined at a predetermined angle with respect to the extending direction, and the other is inserted into the notch and is assembled in a lattice shape. The inner peripheral surface and the outer peripheral surface of the strip-shaped member inserted according to the cutting angle can be easily set to a predetermined inclination angle.

  The planar light source of the present invention is characterized in that the LED light source is mounted on the surface of the strip-shaped member. That is, in this planar light source, since the LED light source is mounted on the surface of the strip-shaped member, by mounting the LED light source on each corresponding strip-shaped member in advance before assembling the lattice-shaped frame, A reflection frame body in which the LED light source is mounted on the inner peripheral surface can be easily configured.

  Furthermore, the planar light source of the present invention is characterized in that a mounting circuit portion that is connected to the LED light source and includes a connection terminal to the outside is formed on the surface of the strip-shaped member. That is, in this planar light source, a mounting circuit portion that is connected to the LED light source and provided with an external connection terminal is formed on the surface of the strip-shaped member, so the strip-shaped member itself is the mounting substrate for the LED light source. Thus, there is no need to separately prepare and mount a mounting board such as a flexible printed board, and the member cost and the number of mounting processes can be reduced.

  Moreover, the planar light source of the present invention is characterized in that a plurality of the reflection frame bodies are integrated as a grid frame body formed in a grid pattern by integral molding. That is, in this planar light source, the plurality of reflecting frame bodies are integrated as a grid-like frame body formed in a grid shape by integral molding, so that it is more than a case of being constituted by a plurality of members such as strip-like members. Further, the member cost and the number of mounting processes can be reduced.

  In the planar light source of the present invention, the unit illumination units arranged in a row in a certain direction have the light emission surfaces of the LED light sources arranged in different directions from the unit illumination units in other adjacent rows. Features. That is, in this planar light source, the unit illumination units arranged in a row in a certain direction are arranged with the light emission surface of the LED light source in a different direction from the unit illumination units in the other adjacent columns, so that for each adjacent column The incident direction of light is different, the brightness distribution is different between adjacent columns, the brightness is averaged, and good brightness uniformity as a whole can be obtained.

  The liquid crystal display device of the present invention comprises a liquid crystal display panel and the planar light source of the present invention disposed on the back side of the liquid crystal display panel. That is, since the liquid crystal display device includes the planar light source of the present invention, it is light and thin, and can display an image with a large area that can obtain good luminance.

The present invention has the following effects.
That is, according to the planar light source according to the present invention, the reflecting frame whose inner peripheral surface is a reflecting surface, and the light emitting surface that is installed inside or inside the reflecting frame and is disposed on the inner peripheral surface of the reflecting frame. Are provided with a plurality of unit illuminating units composed of LED light sources that emit light with a certain spread angle, and can be reduced in weight and thickness by using a reflective frame. At the same time, by emitting light toward the inner peripheral surface of the reflection frame, luminance unevenness can be reduced and luminance uniformity can be improved.
Therefore, according to the liquid crystal display device provided with the planar light source, it is possible to display an image with a large area that is light and thin and that can obtain good luminance.

  Hereinafter, a planar light source and a liquid crystal display device according to a first embodiment of the present invention will be described with reference to FIGS. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size.

  The planar light source 1 in the present embodiment is a backlight used in a liquid crystal display device, and as shown in FIGS. 1 to 3, a reflective plate 2 whose upper surface is a reflective surface, and above the reflective plate 2. A diffuser plate 3 that diffuses light that is installed and transmitted, a reflective frame 4 that is installed on the reflective plate 2 with the opening surface facing upward, and the inner peripheral surface 4a is a reflective surface, and the reflective frame 4 A plurality of unit illuminating units 6 each including an LED light source 5 which is installed on the inner side and emits light with a certain spread angle with the light emitting surface 5a facing the inner peripheral surface 4a of the reflecting frame 4; It is equipped with. In addition, the unit illumination part 6 comprised with the one reflective frame 4 and the LED light source 5 inside it comprises the one light unit.

  The reflection frame 4 is formed of a white resin in a square frame shape or a rectangular frame shape. In the reflection frame 4, each inner peripheral surface 4 a is formed perpendicular to the opening surface, and the inner peripheral surface 4 a facing the light emitting surface 5 a of the LED light source 5 is parallel to the light emitting surface 5 a. Thus, it is orthogonal to the optical axis of the LED light source 5.

  Each of the LED light sources 5 is a white LED connected to a flexible printed circuit board (not shown). The LED light source 5 is disposed in the vicinity of one piece of the inner peripheral surface 4a of the reflection frame body 4 having a quadrangular frame shape, and the light emitting surface 5a is disposed in parallel to the inner peripheral surface 4a. That is, the LED light source 5 is mounted on the reflection plate 2 together with the flexible printed circuit board with the light emission surface 5a facing in the horizontal direction parallel to the opening surface of the reflection frame 4. The white LED used as the LED light source 5 is, for example, a semiconductor light emitting element (not shown) on the substrate 5b sealed with a sealing resin 5c. As the semiconductor light emitting element, for example, blue (wavelength λ: 470 to 490 nm). ) LED element or ultraviolet light (wavelength λ: less than 470 nm) LED element, in which a plurality of semiconductor layers of gallium nitride compound semiconductor (for example, InGaN compound semiconductor) are stacked on an insulating substrate such as a sapphire substrate It is formed.

  In addition, the sealing resin 5c for sealing the semiconductor light emitting element is mainly composed of a silicone resin, and, for example, a YAG phosphor is added. This YAG phosphor converts white light or ultraviolet light from a semiconductor light emitting element into yellow light and generates white light by a color mixing effect. The LED light source 5 has a reflecting frame on the side surface of the sealing resin 5c other than the tip surface (light emitting surface 5a) so that light is emitted only from the tip surface. In order to increase the light spread angle, a sealing resin 5c without a reflection frame may be employed. As the white LED, various types other than the above can be adopted.

  The diffusing plate 3 is disposed on the plurality of arranged reflection frames 4 and diffuses light from below to make the in-plane light intensity uniform, and is disposed on the diffusing plate main body 7. And the diffusion sheet 8 made. The diffusion plate body 7 and the diffusion sheet 8 are formed of a plate material and a sheet material in which silica particles are dispersed in a transparent resin such as an acrylic resin or a polycarbonate resin.

  The reflection plate 2 is a reflection sheet with a double-sided tape or the like applied to the reflection sheet on the plate body, and the reflection sheet is a metal plate, film, foil or the like having a light reflection function, In this embodiment, a film provided with a silver vapor deposition film is employed. Note that an aluminum metal vapor deposition film or the like may be employed instead of the silver vapor deposition film.

  The unit illumination units 6 are arranged in a matrix composed of a plurality of columns and rows. For example, the shape of the reflection frame 4 and the number of installed frames may be determined so that the mainstream aspect ratio is 16: 9 with a large-sized backlight.

  Furthermore, the unit illumination parts 6 arranged in a row in a certain direction are arranged with the light emitting surface 5a of the LED light source 5 in a different direction from the unit illumination parts 6 in other adjacent rows. For example, as shown in FIG. 1, when the unit illumination units 6 are arranged in two upper and lower rows, in the upper horizontal row, the light emission surface 5a is arranged toward the left side in the figure, and the lower row In one horizontal row, the light emission surface 5a is arranged toward the right side in the figure.

  Further, in the planar light source 1, as shown in FIG. 3, the reflection frame body 4 is installed apart from the diffusion plate 3, and a gap S is provided between them. The gap S (distance between the reflection frame 4 and the diffusion plate 3) is appropriately set so that the shape of the reflection frame 4 does not float on the diffusion plate 3. In addition, the arrow by the virtual line (two-dot chain line) in FIG. 3 has shown the example of the advancing direction of light.

  The liquid crystal display device 10 of the present embodiment is a display device applied to a liquid crystal display such as a large liquid crystal television device, for example, and as shown in FIG. 3, a liquid crystal display panel 11 and a back surface of the liquid crystal display panel 11. The planar light source 1 disposed on the side is provided.

That is, the liquid crystal display device 10 includes the planar light source 1 and a prism sheet 12 that is arranged on the diffusion plate 3 and emits light from the diffusion plate 3 as irradiation light directed upward toward the liquid crystal display panel 11. And the liquid crystal display panel 11 disposed on the prism sheet 12.
In the present embodiment, the screen side of the liquid crystal display panel 11 and the light emission surface side of the planar light source 1 are described as the surface side or the upper surface side.

  The prism sheet 12 is a transparent sheet-like member for condensing light from the diffusion sheet 8 on the upper surface side, and has a prism portion having a plurality of parallel ridge lines on the upper surface side. Further, the prism sheet 12 is set to a position where the ridge line of the prism portion is twisted with respect to the optical axis of the LED light source 5, and in particular to the optical axis of the LED light source 5 as a direction in which high upward directivity is obtained. It is set parallel to the orthogonal direction.

  The liquid crystal display panel 11 is a transmissive or transflective liquid crystal display panel. For example, in the case of the transmissive liquid crystal display panel 11, a TFT liquid crystal method, an STN liquid crystal method, or a TN device in which a liquid crystal material is sealed in a gap between an upper substrate and a lower substrate each having a transparent electrode, an alignment film, and a polarizing plate. A panel body such as a liquid crystal system is provided.

  As described above, the planar light source 1 according to the embodiment is installed on the reflecting plate 2 and the reflecting frame 4 having the inner peripheral surface 4a as the reflecting surface, and is installed inside the reflecting frame 4 and reflects. Since the light source surface 5a is opposed to the inner peripheral surface of the frame 4 and the LED light source 5 is configured to emit light with a certain spread angle, the LED light source Most of the light emitted from 5 is not directly incident on the upper diffusing plate 3, but is reflected by the inner peripheral surface 4 a of the reflecting frame 4 and then incident on the diffusing plate 3. 5 can be converted into a surface light source with a surface shape corresponding to the range surrounded by the reflection frame 4.

In addition, the reflective frame 4 is provided not on the LED light source 5 but on the periphery, and the light emission direction of the LED light source 5 is not on the diffusion plate 3 side directly above but on the inner peripheral surface 4a side of the surrounding reflection frame body 4. The space between the LED light source 5 and the diffusion plate 3 can be set narrow, and the entire light unit can be thinned.
Therefore, the use of the reflective frame 4 can reduce the weight as compared with the conventional light guide plate method, and the LED light source 5 is installed so that light can be emitted toward the inner peripheral surface 4a of the reflective frame 4. As a result, it is possible to reduce luminance unevenness and improve luminance uniformity as compared with a conventional direct type backlight, and to reduce the thickness.

Moreover, since the reflective frame 4 is formed of a white resin, the inner peripheral surface 4a can be a white surface having a reflection effect and a diffusion effect without particularly performing a reflection process or the like.
Furthermore, since there is a gap S between the reflection frame 4 and the diffusion plate 3, light is emitted outside the reflection frame 4 through the gap S, so that light is mutually transmitted between the adjacent reflection frames 4. The boundary of the light shape according to the reflection frame 4 irradiated to the irradiation surface of the diffuser 3 is unclear. Therefore, by adjusting the gap S between the reflecting frame 4 and the diffusing plate 3, the degree of light confinement in the reflecting frame 4 can be set, and the light shape irradiated on the irradiation surface of the diffusing plate 3 can be set. It is possible to make the outline of the reflection frame body 4 reflected and the space between the adjacent reflection frame bodies 4 inconspicuous.

  Moreover, since the unit illumination part 6 in which the reflection frame 4 is square or rectangular is arranged in a matrix shape composed of a plurality of columns and rows, the LED light source 5 is partially driven separately for each unit illumination part 6. By partial luminance control, so-called local dimming can be easily realized. For example, as local dimming, the luminance of the backlight is controlled according to the luminance and contrast of the image displayed on the liquid crystal display panel 11, and the luminance of the backlight is adjusted based on the image data input to the liquid crystal display panel 11. By adjusting the brightness by controlling each unit illumination unit 6 in terms of location and time, it is possible to reduce power consumption and improve contrast, moving image followability, and the like.

  Further, since the unit illumination units 6 arranged in a row in a certain direction are arranged with the light emitting surface 5a of the LED light source 5 in a different direction from the unit illumination units 6 in other adjacent columns, The incident directions are different, the brightness distributions of adjacent columns are different, and the brightness is averaged to obtain good brightness uniformity as a whole.

  Therefore, in the liquid crystal display device 10 that employs the planar light source 1 as a backlight unit, it is lightweight and thin, and a large area image display capable of obtaining good luminance is possible.

  Next, second to tenth embodiments of the planar light source and the liquid crystal display device according to the present invention will be described below with reference to FIGS. In the following description of each embodiment, the same constituent elements described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that, in the first embodiment, the reflector frame 4 is arranged close to the inner peripheral surface 4a of one piece of the rectangular frame, and the inner peripheral surface 4a In contrast to the planar light source 21 according to the second embodiment, which is arranged with the light emitting surface 5a in parallel, as shown in FIG. It is arranged at one of the four corners so that the optical axis is arranged on the diagonal line of the reflection frame 4.

In the second embodiment, since the LED light source 5 is installed at one of the four corners of the reflection frame 4, the inner peripheral surface 4 a facing the light emitting surface 5 a becomes two surfaces and is emitted from the LED light source 5. The reflected light is mainly reflected by the two inner peripheral surfaces 4a.
Also in the second embodiment, the light emitting surface 5a of the LED light source 5 is arranged in a different direction from the unit illumination units 26 in other adjacent rows. For example, as shown in FIG. 4, when the unit illumination units 6 are arranged in two upper and lower rows, in the upper horizontal row, the light emission surface 5 a is arranged toward the lower right side in the figure, and In the lower horizontal row, the light emission surface 5a is arranged toward the upper left side in the figure.

  As described above, the unit illumination units 26 are preferably arranged as described above. However, as another example of the second embodiment, as shown in FIG. 5, the light emission surfaces 5a of the LED light sources 5 are all in the same direction. The unit illumination units 26 may be arranged side by side.

The difference between the third embodiment and the first embodiment is that, in the first embodiment, nothing is provided between the LED light source 5 and the diffusion plate 3, whereas the surface of the third embodiment. In the light source 31, as shown in FIG. 6, the reflection frame body 34 of the unit illumination unit 36 has an eaves part 35 that covers a portion directly above the LED light source 5.
This eaves part 35 is a rectangular plate part provided in a protruding state above the LED light source 5 from the inner peripheral surface 4 a of the reflection frame 34 close to the LED light source 5.

  Moreover, also in the planar light source 41 of 4th Embodiment, the reflection frame 44 of the unit illumination part 46 has the eaves part 45 which covers the part directly above the LED light source 5, as shown in FIG. This is different from other examples of the second embodiment. The eaves portion 45 is a triangular plate portion provided in a protruding state above one of the four corners of the reflection frame 44 close to the LED light source 5 above the LED light source 5.

  As described above, in the third and fourth embodiments, the reflection frame bodies 34 and 44 have the eaves portions 35 and 45 that cover the portion directly above the LED light source 5, so that the diffusion plate 3 directly above the LED light source 5. Light directed in the direction can be shielded by the eaves portions 35 and 45, and hot spots can be further reduced.

  The difference between the fifth embodiment and the first embodiment is that, in the first embodiment, the inner peripheral surface 4a of the reflecting frame 4 is arranged vertically on the reflecting plate 2 and faces the LED light source 5 light emitting surface 5a. Whereas the inner peripheral surface 4a is parallel to the light emitting surface 5a, the planar light source 51 of the fifth embodiment is, of the inner peripheral surface 54a of the reflecting frame 54, as shown in FIG. The inner peripheral surface 54a facing the light emitting surface 5a of the LED light source 5 is an upward inclined surface inclined toward the opening surface side.

  In the fifth embodiment, of the inner peripheral surface 54a of the reflecting frame 54, the inner peripheral surface 54a that faces the light emitting surface 5a of the LED light source 5 is an upward inclined surface that is inclined toward the opening surface side. Therefore, the brightness can be further improved by reflecting the light from the LED light source 5 toward the diffusion plate 3 disposed on the opening surface side.

  Moreover, in 5th Embodiment, the internal peripheral surface 54a of the reflective frame 54 distribute | arranged to the back side of the LED light source 5 inclines, and the point which functions also as an eaves part which covers the part directly above the LED light source 5 is the point. This is different from the first embodiment. That is, the inner peripheral surface 54a on the back side, which is the lower surface of the eaves portion, is a downward inclined reflective surface that is inclined toward the inner peripheral surface 54a of the reflecting frame 54 that faces the light emitting surface 5a of the LED light source 5. This is different from the first embodiment. In addition, the arrow by the virtual line (two-dot chain line) in FIG. 8 has shown the example of the advancing direction of light.

  Therefore, in the fifth embodiment, the inner peripheral surface 54a on the back side of the LED light source 5 functions as an eaves portion and is formed on the inner peripheral surface 54a of the reflection frame 54 that faces the light emitting surface 5a of the LED light source 5. Since it is a downward inclined reflecting surface that is inclined to face, the inner peripheral surface 54a side of the reflective frame 54 that faces the light directly upward from the LED light source 5 on the inner peripheral surface 54a (the lower surface of the eaves portion) on the back surface side. The light shielded by the inner peripheral surface 54a (eave portion) on the back side can also contribute to the overall luminance.

  The difference between the sixth embodiment and the first embodiment is that the unit illumination units 6 are arranged in a matrix in the first embodiment, whereas the planar light source 61 of the sixth embodiment is different from that in FIG. As shown in FIG. 4, the outer peripheral surface 4b of the reflective frame 4 is also used as a reflecting surface, and the unit illumination units 66 are staggered with their corners close to each other, and between the adjacent unit illumination units 66, The LED light source 5 that emits light with a certain divergence angle with the light emitting surface 5a facing the outer peripheral surface 4b of the reflecting frame 4 is installed.

  That is, in the planar light source 61 of the sixth embodiment, the outer peripheral surface 4b of the reflection frame 4 is also used as a reflection surface, and between the plurality of unit illumination units 66 arranged in a staggered manner with their corners close to each other. Further, since the LED light source 5 having the light emitting surface 5a opposed to the outer peripheral surface 4b of the reflecting frame 4 is installed, the periphery of the reflecting frame 4 is surrounded in the region between the adjacent unit illumination portions 66. Since the emitted light from the LED light source 5 surrounded by 4b is reflected by the outer peripheral surface 4b, the light can be emitted toward the diffusion plate 3 in this region as well as the unit illumination unit 66. Therefore, by alternately arranging the reflection frame bodies 4 alternately, the number of the reflection frame bodies 4 to be installed side by side is halved as a whole, and the member cost can be reduced.

  The difference between the seventh embodiment and the first embodiment is that, in the first embodiment, the LED light source 5 is installed on the inner side of the reflecting frame 4, whereas in the planar light source 71 of the seventh embodiment. As shown in FIG. 10, a rectangular cutout recess 74c is formed in the reflection frame 74, that is, in a part of the lower part of the reflection frame 74, and the LED light source 5 is accommodated in the cutout recess 74c. It is a point that is installed.

  Therefore, in the seventh embodiment, since the LED light source 5 is installed inside the reflection frame 74, the LED light source 5 is hidden in the reflection frame 74 and the LED light source 5 itself is an obstacle for light reflection and diffusion. In other words, the reflection on the inner peripheral surface 4a of the reflection frame 74 can be performed more efficiently. Further, by providing the reflective frame 74 directly above the LED light source 5, light emitted directly above the LED light source 5 is shielded by the reflective frame 74, thereby preventing the occurrence of hot spots. .

  The difference between the eighth embodiment and the first embodiment is that, in the first embodiment, a plurality of reflecting frame bodies 4 individually formed in a rectangular frame shape are arranged and arranged in a matrix. On the other hand, in the planar light source 81 of the eighth embodiment, as shown in FIGS. 11 and 12, a plurality of reflecting frame bodies 84 are gratings configured by a plurality of strip-like members 85A and 85B assembled in a grid. It is the point integrated as the shape frame 86.

Further, the eighth embodiment is different from the first embodiment in that the LED light source 5 mounted on a flexible printed board (not shown) is attached to the surface of the strip-shaped member 85B and mounted.
Further, the grid-like frame 86 is formed with a plurality of cuts 85a inclined at a predetermined angle with respect to the extending direction in one of the strip-shaped members 85A and 85B (the strip-shaped member 85A) intersecting each other. The other (strip-shaped member 85B) is inserted into these cuts 85a from above and assembled in a lattice shape.

In the present embodiment, the angle of the cut 85a is set to 45 °, but an arbitrary inclination angle can be set. Further, in this embodiment, the strip-shaped member 85B inserted from above into the cut 85a is set to be narrower than the strip-shaped member 85A with the cut 85a in the upper portion, and each strip-shaped member is in an assembled state. The upper end surfaces of 85A and 85B are set to be flush with each other, and the height of the reflection frame 84 is made uniform.
Further, if the strip-shaped member 85B is provided with a cut perpendicular to the extending direction, it is possible to assemble a reflecting frame without a gap below.

  Thus, in the planar light source 81 of the eighth embodiment, the plurality of reflecting frame bodies 84 are integrated as a grid frame body 86 composed of a plurality of strip members 85A and 85B assembled in a grid pattern. Therefore, it is possible to easily produce a grid-like frame 86 in which a plurality of reflection frames 84 are continuously arranged in a matrix with a plurality of strip-like members 85A and 85B, and to arrange the reflection frames of individual members. In addition, the member cost, the number of mounting steps, and the like can be reduced.

Moreover, since the LED light source 5 is mounted on the surface of the strip-shaped member 85B, it is easy to mount the LED light source 5 on each corresponding strip-shaped member 85B in advance before assembling the lattice-shaped frame 86. A reflective frame body 84 in which the LED light source 5 is mounted on the inner peripheral surface can be configured.
Further, one of the strip-shaped members 85A and 85B crossing each other (strip-shaped member 85A) is formed with a notch 85a inclined at a predetermined angle with respect to the extending direction, and the other (strip-shaped member 85B) is inserted into the notch 85a. Therefore, the inner peripheral surface and the outer peripheral surface of the strip-shaped member 85B inserted according to the angle of the notch 85a can be easily set to a predetermined inclination angle.

  In the eighth embodiment, only the strip-shaped members 85B facing and parallel to each other corresponding to two sides of the reflection frame 84 are inclined by inserting them into the inclined cuts 85a. Inclined cuts 85a are formed in all the strip-shaped members 85A and 85B intersecting each other corresponding to the sides, and the strip-shaped members 85A and 85B are tilted by being inserted into the respective cuts 85a to form a lattice. It doesn't matter. In this case, all the inner peripheral surfaces of the reflection frame 84 are inclined, and in particular, when the LED light source 5 is disposed in at least one of the four corners of the reflection frame 84, It is suitable for the case where the inner peripheral surface is inclined.

The difference between the ninth embodiment and the eighth embodiment is that in the eighth embodiment, a grid frame is obtained by inserting an inclined cut 85a into only one of the strip-shaped members 85A and 85B intersecting each other and inserting the other. 86, in the planar light source 91 of the ninth embodiment, as shown in FIG. 13, it extends in the extending direction to both of the strip-shaped members 95A and 95B that intersect with each other and have the same width. On the other hand, by making vertical cuts 95a and 95b and inserting them into each other, a lattice frame 96 is constructed. That is, each of the reflection frames 94 in a matrix arrangement that constitutes the grid frame 96 has a vertical inner peripheral surface as in the first embodiment.
A plurality of cuts 95a in the strip-shaped member 95A are formed at equal intervals in the upper part, and a plurality of cuts 95b in the strip-shaped member 95B are formed at a plurality of equal intervals in positions corresponding to the lower cuts 95a.

Further, the ninth embodiment differs from the eighth embodiment in that a mounting circuit portion 97 that is connected to the LED light source 5 and provided with an external connection terminal 97a is formed on the surface of the strip-shaped member 95B. ing. That is, the LED light source 5 is directly mounted on the surface of the strip-shaped member 95 </ b> B and is electrically connected to the mounting circuit unit 97.
The mounting circuit portion 97 is pattern-wired along the strip-shaped member 95B, and the connection terminal 97a is disposed at the end of the strip-shaped member 95B.

As described above, in the planar light source 91 of the ninth embodiment, the grid frame 96 is configured by inserting the cuts 95a and 95b into both of the intersecting strip members 95A and 95B and inserting them into each other. The lower end surface and the upper end surface of the shaped member 85 can be flush with each other, the height of the reflection frame 94 can be made uniform, and stable mounting onto the reflector 2 can be achieved.
Further, since the mounting circuit portion 97 that is connected to the LED light source 5 and provided with an external connection terminal 97 a is formed on the surface of the strip-shaped member 95 B, the strip-shaped member 95 B itself is the mounting substrate of the LED light source 5. Accordingly, it is not necessary to separately prepare and mount a mounting board such as a flexible printed board, and the member cost and the mounting process can be reduced.

The difference between the tenth embodiment and the ninth embodiment is that, in the ninth embodiment, a plurality of strip-shaped members 95A and 95B are assembled in a lattice shape to form a lattice frame 96. In the planar light source 101 of the tenth embodiment, as shown in FIG. 14, a plurality of reflection frame bodies 104 are integrated as a grid frame body 106 formed in a grid pattern by integral molding.
In the tenth embodiment, the LED light source 5 is mounted on a flexible printed circuit board (not shown) and attached to the inner peripheral surface of the reflection frame body 104 as in the eighth embodiment.

  As described above, in the planar light source 101 of the tenth embodiment, since the grid frame 106 is formed by integral molding, the member cost and the mounting process are further increased as compared with the case where the lattice frame 106 is configured by a plurality of members such as strip-shaped members. The number can be reduced.

  Next, the planar light source and the liquid crystal display device according to the present invention will be described in detail with reference to FIGS.

  First, the photograph which shows the appearance seen from upper direction in the state which made the unit illumination part 6 of 1st Embodiment and the unit illumination part 26 of 2nd Embodiment stand alone is shown in FIG.15 and FIG.16. In these photographs, a white lined square frame indicates the position of the reflective frame 4. As can be seen from these photographs, it can be confirmed that the light emitted from the LED light source 5, which is a point light source, spreads in a plane in the reflection frame 4 and is emitted upward.

  In addition, as shown in FIG. 17, the distance between the reflecting plate 2 and the diffusing plate 3 is set to be the same in a state where the light source is turned on when two unit illumination units 6 according to the first embodiment are arranged. FIGS. 18 and 19 show photographs showing the appearance of the reflective frame 4 when viewed from above, when the height h of the reflective frame 4 is 4 mm, and when the height h of the reflective frame 4 is 2 mm. . As can be seen from these photographs, the height h of the reflection frame 4 is low and the gap S with the diffusion plate 3 is smaller than when the height h of the reflection frame 4 is high and the gap S with the diffusion plate 3 is narrowed. In the case of widening, the outline is blurred and unclear as a whole, and the shape of the reflection frame body 4 and the space between the reflection frame bodies 4 are hardly noticeable.

  Next, as shown in FIG. 20, when the unit light units 26 of the second embodiment are arranged side by side to form a planar light source and all the unit illumination units 6 are turned on, three unit illuminations out of the five units FIGS. 21 and 22 show photographs showing the appearance when only the portion 26 is selectively lit and when viewed from above. As can be seen from these photographs, when only three unit illumination units 26 are selectively lit compared to when all five unit illumination units 26 are lit, the lighting areas are clearly divided into unit illumination units 26. It can be seen that the brightness is partially controlled. Therefore, local dimming can be performed according to the brightness and contrast of the image displayed on the liquid crystal display panel 11 by controlling the brightness of each unit illumination unit 26 individually.

  In addition, this invention is not limited to said each embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

For example, in each of the above embodiments, a square frame-shaped or rectangular frame-shaped reflective frame is used, but other polygonal reflective frames such as a triangular frame or a hexagonal frame may be adopted. .
In addition, it is possible to emit light of any color using RGB-LEDs as LED light sources. For example, as an RGB-LED, an LED in which a red LED element (R), a green LED element (G), and a blue LED element (B) are mounted in one package is used as a light source, or light is emitted to one reflecting frame. You may arrange | position the LED light source from which a color differs, respectively. In these cases, by controlling the applied current in each LED, it becomes possible to illuminate with the light of various colors for the entire planar light source or for each unit illumination unit.

  Further, in the planar light source of each of the above embodiments, one diffusion plate body and one diffusion sheet are used as the diffusion plate, but either one may be omitted or at least one may be used in a plurality. Furthermore, the diffusion plate may be a backlight unit disposed between the prism sheet and the liquid crystal display panel. That is, the diffusion plate (the diffusion plate main body and the diffusion sheet) is appropriately set in terms of the installation position, the number of sheets, and the like in consideration of the number of sheets and haze in order to adjust luminance unevenness.

In addition, although one prism sheet is used, a backlight unit employing two prism sheets may be used.
In each of the above embodiments, a diffusion plate, a diffusion sheet, and a prism sheet having a size corresponding to the size of the liquid crystal display panel are employed. You may employ | adopt the structure which arranges the divided thing side by side.

In 1st Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is the top view and side view which show the planar light source which arranged six unit illumination parts except a diffuser plate and a reflecting plate. In 1st Embodiment, it is a perspective view which shows the planar light source which arranged the four unit illumination parts except the diffuser plate and the reflecting plate. In 1st Embodiment, it is an expanded sectional view of the principal part which shows a liquid crystal display device. In 2nd Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is the top view and side view which show the planar light source which arranged 6 unit illumination parts except a diffuser plate and a reflecting plate. In the other example of 2nd Embodiment, it is a perspective view which shows the planar light source which arranged the 4 unit illumination part except the diffuser plate and the reflecting plate. In 3rd Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is a perspective view which shows the planar light source which arranged four unit illumination parts except a diffuser plate and a reflecting plate. In 4th Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is a perspective view which shows the planar light source which arranged the four unit illumination parts except a diffuser plate and a reflecting plate. In 5th Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is an expanded sectional view of the principal part which shows a liquid crystal display device. In 6th Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is a top view which shows the planar light source which arranged the unit illumination part in zigzag arrangement | positioning except the diffuser plate and the reflecting plate. In 7th Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is an expanded sectional view of the principal part which shows a liquid crystal display device. In 8th Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is a perspective view which shows the grid | lattice-like frame body at the time of insertion of a strip-shaped member. In 8th Embodiment, it is a perspective view which shows a planar light source. In 9th Embodiment of the planar light source and liquid crystal display device which concern on this invention, it is a perspective view which shows the planar light source at the time of insertion of a strip-shaped member. It is a perspective view which shows a planar light source in 10th Embodiment of the planar light source and liquid crystal display device which concern on this invention. In the Example of the planar light source and liquid crystal display device which concerns on this invention, it is the photograph at the time of lighting the unit illumination part single-piece | unit of 1st Embodiment. In the Example of the planar light source and liquid crystal display device which concerns on this invention, it is a photograph at the time of lighting the unit illumination part single-piece | unit of 2nd Embodiment. In the Example of the planar light source and liquid crystal display device which concerns on this invention, it is a top view which shows the planar light source which arranged two unit illumination parts of 1st Embodiment side by side except a diffuser plate and a reflecting plate. It is the photograph at the time of lighting the unit illumination part of a reflective frame with a height of 4 mm in the planar light source of FIG. It is the photograph at the time of lighting the unit illumination part of a reflective frame with a height of 2 mm in the planar light source of FIG. In the Example of the planar light source and liquid crystal display device which concerns on this invention, it is a top view which shows the planar light source which arranged five unit illumination parts of 2nd Embodiment, except a diffuser plate and a reflecting plate. It is a photograph at the time of making all the five unit illumination parts light in the planar light source of FIG. FIG. 21 is a photograph when three selected unit illumination units are turned on in the planar light source of FIG. 20.

Explanation of symbols

  1, 21, 31, 41, 51, 61, 71, 81, 91, 109 ... planar light source, 2 ... reflector, 3 ... diffuser plate, 4, 34, 44, 54, 74, 84, 94, 104 ... Reflecting frame, 4a, 54a ... inner peripheral surface of the reflecting frame, 4b ... outer peripheral surface of the reflecting frame, 5 ... LED light source, 6, 26, 36, 46, 66 ... unit illumination unit, 7 ... diffuser plate body, DESCRIPTION OF SYMBOLS 8 ... Diffusion sheet, 10 ... Liquid crystal display device, 11 ... Liquid crystal display panel, 12 ... Prism sheet, 35, 45 ... Eaves part, S ... Gap between reflection frame and diffusion plate, 85A, 85B, 95A, 95B ... strip-shaped member, 85a, 95a, 95b ... notches, 86, 96, 106 ... grid frame, 97 ... mounting circuit part, 97a ... connection terminal

Claims (15)

A reflecting plate whose upper surface is a reflecting surface;
A diffusing plate that is installed above the reflecting plate and diffuses the transmitted light;
A reflective frame having an opening surface facing upward and an inner peripheral surface as a reflective surface, and an inner peripheral surface of the reflective frame that is installed inside or inside the reflective frame. A planar light source comprising: a plurality of unit illuminating units each including an LED light source that emits light with a certain divergence angle with the light emitting surfaces facing each other. The planar light source according to claim 1,
The planar light source, wherein the reflective frame is made of a white resin. The planar light source according to claim 1 or 2,
The planar light source, wherein the reflective frame has an eaves portion that covers a portion directly above the LED light source. The planar light source according to claim 3,
The planar light source characterized in that the lower surface of the eaves portion is a downward inclined reflective surface that is inclined toward the inner peripheral surface of the reflective frame opposite to the light emitting surface of the LED light source. In the planar light source according to any one of claims 1 to 4,
A planar light source characterized in that, of the inner peripheral surface of the reflective frame, an inner peripheral surface facing the light emitting surface of the LED light source is an upward inclined surface inclined toward the opening surface side. In the planar light source according to any one of claims 1 to 5,
A planar light source characterized in that there is a gap between the reflection frame and the diffusion plate. The planar light source according to any one of claims 1 to 6,
The reflective frame is a square frame or a rectangular frame,
The planar light source, wherein the unit illumination units are arranged in a matrix composed of a plurality of columns and rows. The planar light source according to any one of claims 1 to 6,
The reflection frame body is a square frame shape or a rectangular frame shape and the outer peripheral surface is also a reflection surface,
The unit illumination units are arranged in a staggered manner with the corners close to each other,
An LED light source that emits light with a certain divergence angle with the light emitting surface opposed to the outer peripheral surface of the reflecting frame is installed between the adjacent unit illumination units. light source. The planar light source according to any one of claims 1 to 6,
A planar light source, wherein the plurality of reflection frame bodies are integrated as a grid frame body constituted by a plurality of strip-shaped members assembled in a grid pattern. The planar light source according to claim 9,
A planar light source characterized in that at least one of the strip-shaped members intersecting each other is formed with a notch inclined at a predetermined angle with respect to the extending direction, and the other is inserted into the notch and assembled in a lattice shape. . The planar light source according to claim 9 or 10,
A planar light source, wherein the LED light source is mounted on a surface of the strip-shaped member. The planar light source according to claim 11,
A planar light source characterized in that a mounting circuit portion that is connected to the LED light source and includes an external connection terminal is formed on the surface of the strip-shaped member. The planar light source according to any one of claims 1 to 6,
A planar light source, wherein the plurality of reflecting frame bodies are integrated as a grid-like frame body formed in a grid shape by integral molding. The planar light source according to any one of claims 7 to 13,
The planar light source characterized in that the unit illumination units arranged in a row in a certain direction have the light emission surfaces of the LED light sources arranged in a different direction from the unit illumination units in other adjacent rows. A liquid crystal display panel;
A liquid crystal display device comprising: the planar light source according to claim 1, which is disposed on a back surface side of the liquid crystal display panel.