JP5731418B2 - Illumination device and liquid crystal display device including the same - Google Patents

Description

  The present invention relates to an illuminating device in which a plurality of point light sources are two-dimensionally arranged on a bottom plate and illuminates an illumination object from directly below, and a liquid crystal display device including the illuminating device.

  Conventionally, as an illumination device for illuminating a liquid crystal panel of a liquid crystal display device, for example, there is one disclosed in Patent Document 1. In this illuminating device, LEDs (light emitting diodes) are two-dimensionally arranged on a substrate, and light emitted from the LEDs is diffused by a diffusing lens so that the liquid crystal panel is illuminated from directly below. On the substrate, a reflection sheet having a hole in which a diffusing lens is arranged is formed to improve the light use efficiency. Further, a convex portion protruding outward is provided on a part of the peripheral surface of the diffusing lens, and the reflective sheet is provided with an edge of a hole in the reflective sheet interposed between the convex portion and the substrate. Is prevented from lifting from the substrate.

Japanese Patent Laying-Open No. 2011-3549 (see claim 1, paragraphs [0010], [0015], [0029], [0030], FIG. 1 to FIG. 4, FIG. 7, etc.)

  By the way, in the above-described conventional direct type illumination device, substrates on which LEDs having the same light distribution are mounted in a line are arranged side by side on the bottom plate of the backlight chassis. In this way, in the configuration in which the light distribution of the LEDs is all the same, the luminance unevenness of each LED is in a wide range (for example, from one end side to the other end side of the LED arrangement region) in both directions perpendicular to each other in the plane along the bottom plate. In other words, the luminance unevenness is easily recognized as a linear luminance unevenness (bright line unevenness) or a spot-like luminance unevenness (bright spot unevenness). Hereinafter, this point will be described in more detail.

  FIG. 7A is a plan view of the illuminating device 101 in which LED substrates 103 on which a plurality of LEDs 102 (102a) having the same light distribution A are mounted in a line are arranged on the bottom plate 104a of the backlight chassis 104. FIG. FIG. 7B is an explanatory diagram schematically showing the luminance unevenness of the LED 102a viewed from the outside of the illumination device 101 of FIG. 7A. FIG. 8A shows an LED substrate 103 on which a plurality of LEDs 102 (102b) having the same light distribution B (different from the light distribution A) are mounted in a line on the bottom plate 104a of the backlight chassis 104. FIG. 8B is an explanatory view schematically showing unevenness in luminance of the LED 102b visually recognized from the outside of the illumination device 101 of FIG. 8A. In addition, in order to distinguish LED102a * 102b on drawing, LED102b is shown with the hatching in Fig.8 (a). In addition, the x mark and the black circle mark in FIGS. 7B and 8B indicate luminance unevenness corresponding to the LEDs 102a and 102b, respectively.

  For convenience of explanation below, the long side direction of the rectangular bottom plate 104a in plan view is defined as the H direction, and the short side direction is defined as the V direction. 7 and 8, it is assumed that the arrangement pitches of the LEDs 102 in the H direction and the V direction are the same.

  Here, as the light distribution A, for example, the light distribution in the case where the spread (radiation angle) of the light distribution (emitted light) in the V direction of the LED 102a is smaller than the arrangement pitch of the LEDs 102a in the V direction can be considered. . Further, as the light distribution B, for example, when the spread of the light distribution in the H direction and the V direction of the LED 102b is both smaller than the arrangement pitch in the H direction and the V direction of the LED 102b, or the front direction (optical axis direction) The light distribution when strong light is generated can be considered.

  As shown in FIG. 7A, when the LEDs 102a having the same light distribution A are continuously arranged at a constant interval over a wide range in the H direction, the luminance unevenness of the individual LEDs 102a also continues at a constant interval over a wide range in the H direction. And line up. At this time, since the spread of the light distribution of the LEDs 102a is small in the V direction, as shown in FIG. 7B, the luminance unevenness of each LED 102a forms a linear bright line unevenness in the H direction. If the linear bright line unevenness is continuously arranged at a constant interval over a wide range in the V direction, since the bright line unevenness appears in a wide range in the V direction, the bright line unevenness within the range is easily visible. .

  Further, as shown in FIG. 8A, when the LEDs 102b having the same light distribution B are continuously arranged at a constant interval over a wide range in the H direction, the luminance unevenness of the individual LEDs 102b is also constant over a wide range in the H direction. Lined up continuously. At this time, since the spread of the light distribution of the LED 102b is small in both the H direction and the V direction, or the intensity of light near the optical axis is high, as shown in FIG. The brightness unevenness is a spot-like bright spot unevenness. When the spot-like bright spot unevenness is continuously arranged in the V direction over a wide range at a constant interval, the bright spot unevenness appears in a wide range in the V direction, and thus the bright spot unevenness within the range is visually recognized. It becomes easy.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to obtain luminance unevenness of a point light source having the same light distribution in at least one of two directions perpendicular to each other in a plane along the bottom plate. It is possible to avoid the occurrence of bright line unevenness and bright spot unevenness in a wide range, thereby making it difficult to visually recognize brightness unevenness of individual point light sources as bright line unevenness or bright spot unevenness. An object of the present invention is to provide an illumination device and a liquid crystal display device including the illumination device.

  The lighting device of the present invention is a lighting device in which a plurality of point light sources are two-dimensionally arranged on a bottom plate and emits light in a plane shape in a direction facing the bottom plate. Point light sources having different light distributions are included, and the point light sources having different light distributions are mixed in at least one of the first direction and the second direction perpendicular to each other in a plane along the bottom plate. It is characterized by being.

  According to the above configuration, the point light sources having different light distributions included in the plurality of point light sources are mixed in at least one of the first direction and the second direction perpendicular to each other in the plane along the bottom plate. doing. Here, when point light sources having different light distributions are mixed in only one of the first direction and the second direction, and point light sources having the same light distribution are arranged side by side in the other direction. , Line-like bright line unevenness due to the same luminance unevenness continuing in the other direction, or dot-like luminance unevenness (bright spot unevenness) is lined up, but differs depending on the point light source with different light distribution in the one direction. Since luminance unevenness is mixed, such bright line unevenness and bright spot unevenness do not line up in a wide range (for example, from one end side to the other end side of the point light source arrangement region) in the one direction. This makes it difficult to recognize bright line unevenness and bright spot unevenness caused by luminance unevenness of a point light source with the same light distribution as such unevenness.

  In addition, when the point light sources having different light distributions are mixed in both the first direction and the second direction, different luminance unevenness due to the point light sources having different light distributions is mixed in the two directions. Luminance unevenness due to a point light source having the same light distribution is not arranged over a wide range in both directions, and bright line unevenness and bright spot unevenness caused by the luminance unevenness are not arranged over a wide range in both directions.

  Therefore, in any of the above cases, it is possible to make it difficult for the luminance unevenness of each point light source to be visually recognized as bright line unevenness or bright spot unevenness.

  In the illumination device of the present invention, the point light sources having different light distributions may be arranged alternately in at least one of the first direction and the second direction.

  In the first direction and the second direction, in the direction in which the point light sources having different light distributions are alternately arranged, the luminance unevenness of the point light sources having the same light distribution is not continuously arranged. Accordingly, it is possible to reliably make it difficult for the luminance unevenness of each point light source to be visually recognized as bright line unevenness or bright spot unevenness.

  In the illumination device of the present invention, each of the plurality of point light sources is disposed on the substrate via any one of a plurality of mounting substrates, and the plurality of mounting substrates have a plurality of first light distributions. A plurality of first mounting substrates mounted side by side in the first direction and a plurality of point light sources having a second light distribution different from the first light distribution. A plurality of second mounting boards mounted side by side, and the plurality of first and second mounting boards may be alternately arranged in the second direction.

  In this case, the point light sources having different light distributions are alternately arranged in the second direction by a simple configuration in which two types of mounting boards, the first mounting board and the second mounting board, are alternately arranged in the second direction. In order to make it difficult to visually recognize bright line unevenness and bright spot unevenness, different brightness unevennesses are alternately formed in the second direction.

  In the illuminating device of the present invention, each of the plurality of point light sources is disposed on the substrate via one of a plurality of mounting substrates, and the plurality of mounting substrates have a first light distribution. Point light sources and point light sources having a second light distribution different from the first light distribution are all arranged alternately in the same order in the first direction, and the plurality of mounting boards May be arranged side by side in the second direction.

  In this case, with the simple configuration of arranging the same type of mounting boards in the second direction, the point light sources having different light distributions are alternately arranged in the first direction, and different luminance unevenness is alternately formed in the first direction. In addition, it is possible to make it difficult to visually recognize bright line unevenness and bright spot unevenness.

  In the illumination device of the present invention, each of the plurality of point light sources is disposed on the substrate via any of a plurality of mounting substrates, and the plurality of mounting substrates have a first light distribution. A plurality of first mounting boards in which light sources and point light sources having a second light distribution different from the first light distribution are alternately arranged in the first direction; and the first And the point light source having the second light distribution are arranged so as to be alternately arranged in the first direction, and the arrangement order of these point light sources is the first light source. A plurality of second mounting boards that are opposite to the mounting board may be included, and the plurality of first and second mounting boards may be alternately arranged in the second direction.

  In this case, each of the point light sources having different light distributions is arranged in the first and second by a simple configuration in which two types of mounting boards, the first mounting board and the second mounting board, are alternately arranged in the second direction. It is possible to make it difficult to visually recognize bright line unevenness and bright spot unevenness by alternately arranging different luminance unevenness in both directions by arranging them alternately in both directions.

  In the illumination device of the present invention, each of the plurality of point light sources may be formed of a light emitting diode.

  In this case, the effect of the present invention described above can be obtained in a configuration using an LED as a point light source.

  In the illuminating device of the present invention, the light emitting diode may emit white light.

  In this case, the above-described effects of the present invention can be obtained in a configuration using a so-called white diode as a point light source.

  The illuminating device of the present invention may include a diffusing lens that is provided corresponding to each of the plurality of point light sources and diffuses light emitted from each point light source.

  In this configuration, since the light emitted from each point light source is diffused by the diffusing lens, the effect of the present invention that makes it difficult to visually recognize luminance unevenness of each point light source as bright line unevenness or bright spot unevenness is further achieved. Rise.

  The illuminating device of the present invention may further include a diffusing plate that diffuses light incident through the diffusing lens corresponding to each of the plurality of point light sources.

  In this case, the above-described effect of the present invention can be obtained in the configuration using the diffusion plate. For example, in a thin illuminating device, since the distance between the point light source and the diffuser plate is short, incident light cannot be sufficiently diffused even if a diffuser plate is used, and bright line unevenness and bright spot unevenness are likely to occur. In such a case, the configuration of the present invention in which bright line unevenness and bright spot unevenness are difficult to be visually recognized is very effective.

  The liquid crystal display device of the present invention may include the above-described illumination device of the present invention and a liquid crystal panel that performs display by modulating light supplied from the illumination device.

  By adopting a configuration in which the liquid crystal panel is illuminated with the illumination device of the present invention in which bright line unevenness and bright spot unevenness are hardly visible, good display quality can be obtained with the liquid crystal panel.

  According to the present invention, different luminance unevenness of each point light source having different light distribution is mixed in at least one of the first direction and the second direction perpendicular to each other in the plane along the bottom plate. The bright line unevenness and bright spot unevenness caused by the brightness unevenness of the point light source are not arranged in a wide range at least in one direction. Therefore, it is possible to make it difficult for the luminance unevenness of each point light source to be visually recognized as bright line unevenness or bright spot unevenness.

It is sectional drawing which shows the schematic structure of the liquid crystal display device of one Embodiment of this invention. (A) is a top view of the backlight of the said liquid crystal display device, (b) is explanatory drawing which shows typically the brightness nonuniformity when the said backlight is seen from the diffuser plate side. It is sectional drawing of the diffusion lens of the said backlight. It is a graph which shows typically the luminance distribution after passing through the diffusion lens and the diffusion plate of the light emitted from one LED of the backlight. (A) is a top view of the backlight of the liquid crystal display device of other embodiment of this invention, (b) shows typically the brightness nonuniformity when the said backlight is seen from the diffuser plate side. It is explanatory drawing. (A) is a top view of the backlight of the liquid crystal display device of further another embodiment of this invention, (b) is a brightness | luminance nonuniformity when the said backlight is seen from the diffuser plate side typically. It is explanatory drawing shown. (A) is a top view of the conventional illuminating device which comprised several LED by the thing of the same light distribution, (b) shows typically the brightness nonuniformity of LED visually recognized from the exterior of the said illuminating device. It is explanatory drawing. (A) is a top view of the conventional illuminating device which comprised several LED by the same light distribution and the thing of the light distribution different from Fig.7 (a), (b) is the above-mentioned illuminating device. It is explanatory drawing which shows typically the brightness nonuniformity of LED visually recognized from the outside.

[Embodiment 1]
FIG. 1 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 1 of the present embodiment. The liquid crystal display device 1 includes a liquid crystal panel 2 and a backlight 3.

  The liquid crystal panel 2 is a liquid crystal display element that displays light by modulating light supplied from the backlight 3, and is configured by sandwiching a liquid crystal layer between a pair of substrates. On one substrate, a source wiring and a gate wiring arranged so as to be orthogonal to each other, and a switching element (for example, TFT: Thin Film Transistor) for turning on / off driving of a pixel surrounded by the adjacent source wiring and gate wiring And pixel electrodes connected to the switching elements. The other substrate is provided with a color filter including R (red), G (green), and B (blue) color filters provided corresponding to each pixel, a common electrode common to each pixel, and the like. . In addition, an alignment film for aligning liquid crystal molecules is provided on the liquid crystal layer side of each substrate, and a polarizing plate that transmits only predetermined polarized light is provided on the outer side (the side opposite to the liquid crystal layer) of each substrate. Is provided.

  The backlight 3 is a direct-type surface light source device (illumination device) that is disposed directly below the back surface of the liquid crystal panel 2 and illuminates the liquid crystal panel 2 in a planar shape. The backlight 3 includes a backlight chassis 11, an LED 12, an LED substrate 13, a diffusing lens 14, a diffusing plate 15, an optical sheet 16, a reflecting sheet 17, and a circuit board (not shown). The circuit board described above is a circuit board for controlling the light emission of the LED 12, but may include a circuit board for driving the liquid crystal panel 2 and other boards (power supply board, control board).

  The backlight chassis 11 is a chassis member formed by bending one sheet metal into a predetermined shape, and includes a bottom plate 11a and a side plate 11b. The bottom plate 11a is formed in a rectangular shape in plan view, and a plurality of LEDs 12 are arranged on one surface (surface on the liquid crystal panel 2 side) via the LED substrate 13. The side plate 11b is connected to the outer peripheral portion (four side portions of the bottom plate 11a) of the bottom plate 11a so as to rise substantially perpendicular to the bottom plate 11a.

  For convenience of explanation below, two directions perpendicular to each other in a plane along the bottom plate 11a are referred to as an H direction (first direction) and a V direction (second direction). The H direction corresponds to the long side direction of the bottom plate 11a, and the V direction corresponds to the short side direction of the bottom plate 11a.

  FIG. 2A is a plan view of the backlight 3. In FIG. 2A, illustration of the diffusion lens 14, the diffusion plate 15, the optical sheet 16, and the reflection sheet 17 is omitted for convenience. Further, the cross-sectional view of the backlight 3 in FIG. 1 corresponds to the cross-sectional view taken along the line A-A ′ in FIG. FIG. 2B is an explanatory view schematically showing luminance unevenness when the backlight 3 is viewed from the diffusion plate 15 side. This luminance unevenness will be described later.

  The LED 12 is a light emitting diode as a point light source, and is mounted in a line shape in the H direction on an LED substrate 13 as a mounting substrate. In FIG. 2A, six LEDs 12 are mounted on one LED substrate 13, but the number of LEDs 12 mounted is not limited to this number.

  Each LED 12 is composed of a white diode that emits white light. The white diode may include, for example, a blue LED and a phosphor that emits yellow light when excited by blue light, or emits green light when excited by blue LED and blue light. You may be comprised including the fluorescent substance which radiate | emits, and the fluorescent substance which is excited by blue light and radiate | emits red light. In any case, white light can be obtained by mixing the blue light with other color lights.

  The LED substrate 13 is provided side by side in the H direction and the V direction on the bottom plate 11a. Note that a plurality of LED substrates 13 arranged in the H direction may be configured by one LED substrate 13 and arranged in the V direction. By arranging the LED substrate 13 on the bottom plate 11a in this way, the plurality of LEDs 12 are two-dimensionally arranged on the bottom plate 11a via any of the LED substrates 13, and the bottom plate 11a Light can be emitted in a planar shape in the opposite direction, and the liquid crystal panel 2 to be illuminated can be illuminated in a planar shape from directly below.

  The diffusion lens 14 shown in FIG. 1 is provided on the LED substrate 13 corresponding to each of the plurality of LEDs 12 and diffuses the light emitted from each LED 12. The detailed structure of the diffusing lens 14 will be described later. By providing the diffusing lens 14, the light from the LEDs 12 is diffused by the diffusing lens 14, so that even when the distance between the adjacent LEDs 12 is large, dot-like unevenness is hardly generated in the luminance distribution by each LED 12. As a result, the number of LEDs 12 can be reduced and the cost can be reduced. In addition, although it is good also as a structure which excluded the diffuser lens 14, it is desirable to set it as the structure which provided the diffuser lens 14 from a viewpoint of reducing the brightness nonuniformity of LED12.

  The diffusing plate 15 further diffuses and uniformizes the light incident through the diffusing lens 14 corresponding to each of the plurality of LEDs 12, and is formed in a flat plate shape. The liquid crystal panel 2 is further formed than the diffusing lens 14. Arranged on the side. The optical sheet 16 emits light that has passed through the diffusion plate 15 as planar light, and includes a lens sheet, a prism sheet, a retroreflective sheet, and the like. Each end of the diffusion plate 15 and the optical sheet 16 is supported by the side plate 11 b of the backlight chassis 11 via the end of the reflection sheet 17.

  The reflection sheet 17 has an opening 17a through which each LED 12 is exposed, and is disposed on the bottom plate 11a so as to cover the LED substrate 13. The light is emitted from the LED 12 and directly incident thereon, and is emitted from the LED 12. The light that is reflected by the diffuser plate 15 and the like is incident again on the liquid crystal panel 2 side. Thereby, the utilization efficiency of the light radiate | emitted from LED12 can be improved.

  The reflection sheet 17 has an edge portion 17b that rises obliquely with respect to the bottom plate 11a outside the arrangement region of the LEDs 12 (LED substrate 13). An end portion (outer peripheral portion) of the edge portion 17 b is supported from below by the side plate 11 b of the backlight chassis 11.

  By providing the reflection sheet 17, the periphery of the screen of the liquid crystal panel 2 is illuminated by the light emitted from the LED 12 and reflected by the edge 17 b of the reflection sheet 17 without arranging the LEDs 12 around the bottom plate 11 a. be able to. Therefore, since it is not necessary to arrange the LEDs 12 in the peripheral portion of the bottom plate 11a, the number of LEDs 12 can be further reduced and the cost can be reduced.

  Next, details of the structure of the diffusing lens 14 will be described. FIG. 3 is a cross-sectional view of the diffusing lens 14.

  The diffusing lens 14 includes a lens portion 14a and a plurality of (for example, three) leg portions 14b for supporting the lens portion 14a on the LED substrate 13, and has a rotating body shape (as viewed in a plan view) as a whole. In a circular shape). The leg portions 14b are provided at equal intervals (for example, at an interval of 120 degrees) in the direction along the outer periphery of the lens portion 14a, and are attached to predetermined positions of the LED substrate 13 by, for example, an adhesive (not shown). By adjusting the length of each leg portion 14b, the mounting angle of the diffusing lens 14 with respect to the LED substrate 13 can be adjusted. In this embodiment, the length of each leg portion 14b is the same. . As a result, the central axis (optical axis) C of the diffusing lens 14 is perpendicular to the bottom plate 11a.

  The lens portion 14a has a light emitting surface (upper surface) 14c and a lower surface 14d. The light exit surface 14c is recessed toward the LED 12 in the central region (including the central axis C) close to the central axis C, and convex toward the opposite side of the LED 12 in the peripheral region outside the lens radial direction with respect to the central region. It is formed in the shape. Further, in the lower surface 14 d, a portion facing the LED 12 is a concave portion 14 e that is recessed on the opposite side to the LED 12.

  With such a configuration of the diffusing lens 14, the light emitted from the LED 12 is changed (diffused) in the traveling direction to the outside by the concave portion 14 e and the light emitting surface 14 c, and the light spreading angle is increased.

  In addition, the shape of the light emission surface 14c and the lower surface 14d of the diffusion lens 14 is not limited to the above shape, but is a shape in which light emitted from the LED 12 is diffused (a shape in which the light spread angle is increased). Any shape can be used. Therefore, for example, the diffusing lens 14 can be configured without providing a concave portion recessed toward the LED 12 in the central region of the light emitting surface 14c, or the diffusing lens 14 can be configured without forming the concave portion 14e on the lower surface 14d. it can.

  Next, luminance unevenness of each LED 12 will be described. FIG. 4 schematically shows the luminance distribution of the light emitted from one LED 12 after passing through the corresponding diffusing lens 14 and the diffusing plate 15. In the figure, the luminance on the vertical axis is normalized with reference to the luminance on the optical axis of the LED 12 (100%). The luminance of the light emitted from the LED 12 becomes maximum on the optical axis of the LED 12 after passing through the diffusion lens 14 and the diffusion plate 15, and decreases as the absolute value of the emission angle increases. Such a luminance distribution appears as luminance unevenness of the LED 12.

  Such luminance unevenness of the LED 12 varies depending on the light distribution of the LED 12. For example, when the light distribution (radiation angle) of the LED 12 becomes narrower, the half width of the luminance distribution shown in FIG. 4 becomes narrower, and when the light distribution becomes wider, the half width of the luminance distribution becomes wider than the state of FIG. Become. Therefore, for example, when the light distribution of the LEDs 12 is narrower in the V direction than in the H direction, the luminance change of the LEDs 12 increases in the V direction. Therefore, when such LEDs 12 are arranged in the H direction, the luminance unevenness of the individual LEDs 12 is increased. Appears in the H direction as linear luminance unevenness (bright line unevenness). Further, when the light distribution of the LED 12 becomes narrower in both the H direction and the V direction, the luminance change of the LED 12 increases in both directions, so that the luminance unevenness of the individual LEDs 12 appears as dotted luminance unevenness (bright spot unevenness). . If all of the plurality of LEDs 12 have the same light distribution, the bright line unevenness or bright spot unevenness appears in a wide range, and as described above, the bright line unevenness or bright spot unevenness is easily visible.

  Therefore, in this embodiment, in order to make it difficult to visually recognize bright line unevenness and bright spot unevenness, the plurality of LEDs 12 are configured by LEDs having different light distributions. Hereinafter, this point will be described.

  As shown to Fig.2 (a), several LED12 contains LED12a * 12b from which light distribution differs. In addition, in order to distinguish LED12a * 12b on drawing, in FIG. 2A, LED12b is shown with hatching. For convenience of explanation, the light distribution of the LEDs 12a and 12b is referred to as light distribution A and B, respectively.

  Here, as the light distribution A (first light distribution), for example, the spread of the light distribution in the V direction with respect to the arrangement pitch of the LEDs 12a in the V direction is the spread of the light distribution in the H direction with respect to the arrangement pitch of the LEDs 12a in the H direction. A light distribution that is smaller than that can be considered. In addition, as the light distribution B (second light distribution), for example, a light distribution in which the spread of the light distribution in the H direction and the V direction becomes smaller than the arrangement pitch in the H direction and the V direction of the LEDs 12b ( For example, when the light distribution in the H direction and the V direction of the LED 12b is the same as the spread in the V direction of the light distribution A) or when strong light is generated in the front direction (the optical axis direction of the LED 12b) Light distribution can be considered.

  In the present embodiment, the plurality of LED substrates 13 includes a plurality of LED substrates 13a (first mounting substrate) and a plurality of LED substrates 13b (second mounting substrate). A plurality of LEDs 12a having a light distribution A are mounted side by side in the H direction on the LED substrate 13a, and a plurality of LEDs 12b having a light distribution B are mounted side by side in the H direction on the LED substrate 13b. The LED boards 13a and 13b are alternately arranged in the V direction. Thus, the LEDs 12a and 12b mounted on the LED boards 13a and 13b are arranged on the bottom plate 11a so as to be alternately arranged in the V direction, and are mixed in the V direction. On the other hand, in the H direction, a plurality of LEDs 12a having the same light distribution or a plurality of LEDs 12b having the same light distribution are continuously arranged at a predetermined pitch.

  Since the spread of the light distribution of the LEDs 12a is narrower in the V direction than in the H direction, when the LEDs 12a having the same light distribution are arranged in the H direction, the luminance unevenness of the individual LEDs 12a becomes a linear luminance unevenness in the H direction. It forms (refer FIG.2 (b)). On the other hand, since the spread of the light distribution of the LEDs 12b is narrow in both the H direction and the V direction, when the LEDs 12b having the same light distribution are arranged side by side in the H direction, the luminance unevenness of the individual LEDs 12a becomes point-like bright spot unevenness. Appears as Note that the x mark and the black circle mark in FIG. 2B indicate the luminance unevenness corresponding to the LEDs 12a and 12b, respectively (the manner of illustration is the same in other drawings).

  However, since the LEDs 12a and 12b having different light distributions are mixed in the V direction, the bright line unevenness and the bright spot unevenness are wide in the V direction (for example, from one end side to the other end side of the LED 12 arrangement region). Up to) will not line up continuously. As a result, the range in which the bright line unevenness or bright spot unevenness appears collectively in the V direction is narrower than when the LEDs 12 are all configured with the same light distribution. Therefore, the bright line unevenness and bright spot unevenness are reduced. , It can be difficult to recognize such unevenness. That is, by mixing LEDs 12a and 12b having different light distributions in the V direction, it is possible to make it difficult for the luminance unevenness of the individual LEDs 12a and 12b to be visually recognized as bright line unevenness and bright spot unevenness.

  In particular, since the LEDs 12a and 12b having different light distributions are arranged alternately in the V direction, the luminance unevenness of the LEDs 12 (LED 12a or LED 12b) having the same light distribution is continuously arranged in the V direction. In the V direction, the range in which bright line unevenness or bright spot unevenness appears collectively is surely narrowed. Accordingly, it is possible to reliably make it difficult to visually recognize the luminance unevenness of the individual LEDs 12a and 12b as bright line unevenness or bright spot unevenness.

  Further, by using two types of LED boards 13, that is, an LED board 13a on which a plurality of LEDs 12a are mounted and an LED board 13b on which a plurality of LEDs 12b are mounted, these boards are alternately arranged in the V direction. With the simple configuration, the LEDs 12a and 12b having different light distributions are alternately arranged in the V direction, and different luminance unevenness is alternately formed in the V direction, thereby obtaining the above effect of making it difficult to visually recognize the bright line unevenness and the bright spot unevenness. Can do.

  Moreover, in this embodiment, LED12 which radiate | emits white light is used as several point light sources arrange | positioned on the baseplate 11a. Since the LED 12 has luminance unevenness, the above-described bright line unevenness and bright spot unevenness are easily visually recognized. Therefore, the configuration of the present embodiment that makes it difficult to visually recognize the bright line unevenness and the bright spot unevenness is very effective particularly in the configuration using the LED 12 as a point light source.

  Further, in the present embodiment, the diffusion lens 14 is provided corresponding to each of the plurality of LEDs 12, and the light emitted from each LED 12 is diffused by the diffusion lens 14, so that the luminance unevenness of each LED 12 is diffused. It can be reduced by the lens 14. Therefore, the effect of this embodiment that makes it difficult for the luminance unevenness of each LED 12 to be visually recognized as bright line unevenness or bright spot unevenness is further enhanced.

  In addition, light incident through the diffusion lens 14 corresponding to each LED 12 is diffused by the diffusion plate 15, and the luminance distribution is made uniform. At this time, for example, in the thin backlight 3, the distance between the LED 12 and the diffusion plate 15 is short, so that even if the diffusion plate 15 is used, the incident light cannot be diffused and uniformized sufficiently. Bright spot unevenness is likely to occur. Therefore, the configuration of the present embodiment that makes it difficult for the luminance unevenness of each LED 12 to be visually recognized as bright line unevenness or bright spot unevenness is particularly effective for the thin backlight 3 using the diffusion plate 15.

  Further, by using the backlight 3 of the present embodiment in which the bright line unevenness and the bright spot unevenness are difficult to be visually recognized as a lighting device for the liquid crystal panel 2, a good display quality can be obtained in the liquid crystal panel 2.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to the drawings. In addition, the same member number is attached to the same structure as Embodiment 1, and the description is abbreviate | omitted.

  FIG. 5A is a plan view of the backlight 3 of the liquid crystal display device 1 of the present embodiment, and FIG. 5B schematically shows luminance unevenness when the backlight 3 is viewed from the diffusion plate 15 side. FIG. In FIG. 5A, illustration of the diffusion lens 14, the diffusion plate 15, the optical sheet 16, and the reflection sheet 17 is omitted for convenience.

  In the present embodiment, the plurality of LED boards 13 are constituted by one type of LED board 13c (mounting board). On the LED substrate 13c, the LEDs 12a having the light distribution A and the LEDs 12b having the light distribution B are arranged alternately in the same order in the H direction. And the some LED board 13c is arrange | positioned along with the V direction. Accordingly, the LEDs 12a and 12b mounted on the LED boards 13c are arranged on the bottom plate 11a so as to be alternately arranged in the H direction, and are mixed in the H direction. On the other hand, in the V direction, a plurality of LEDs 12a having the same light distribution or a plurality of LEDs 12b having the same light distribution are continuously arranged at a predetermined pitch.

  In the present embodiment, as the light distribution A, for example, the spread of light distribution in the H direction with respect to the arrangement pitch of the LEDs 12a in the H direction is smaller than the spread of light distribution in the V direction with respect to the arrangement pitch of the LEDs 12a in the V direction. Such a light distribution can be considered. For the light distribution B, the same light distribution as in the first embodiment can be considered. Therefore, also in this embodiment, the light distribution A and the light distribution B are different from each other.

  As in this embodiment, the spread of the light distribution of the LEDs 12a is narrower in the H direction than in the V direction. Therefore, when the LEDs 12a having the same light distribution are arranged side by side in the V direction, the luminance unevenness of the individual LEDs 12a is in the V direction. A linear luminance unevenness is formed on the substrate (see FIG. 5B). On the other hand, since the spread of the light distribution of the LEDs 12b is narrow in both the H direction and the V direction, when the LEDs 12b having the same light distribution are arranged side by side in the V direction, the luminance unevenness of the individual LEDs 12a becomes point-like bright spot unevenness. Appears as

  However, since the LEDs 12a and 12b having different light distributions are mixed in the H direction, the bright line unevenness and the bright spot unevenness are not continuously arranged in a wide range in the H direction. As a result, the range in which the bright line unevenness or bright spot unevenness appears in the H direction is narrower than in the case where the LEDs 12 are all configured with the same light distribution, so that the bright line unevenness and bright spot unevenness are reduced. , It can be difficult to recognize such unevenness. In other words, even when LEDs 12a and 12b having different light distributions are mixed in the H direction, it is difficult to visually recognize the luminance unevenness of the individual LEDs 12a and 12b as bright line unevenness and bright spot unevenness as in the first embodiment. can do.

  In particular, since the LEDs 12a and 12b having different light distributions are arranged alternately in the H direction, the luminance unevenness of the LEDs 12 (LED 12a or LED 12b) having the same light distribution is continuously arranged in the H direction. In the H direction, the range in which bright line unevenness or bright spot unevenness appears collectively is surely narrowed. Accordingly, it is possible to reliably make it difficult to visually recognize the luminance unevenness of the individual LEDs 12a and 12b as bright line unevenness or bright spot unevenness.

  In addition, by using the same type of LED board 13, that is, the LED board 13 c in which the LEDs 12 a and 12 b are alternately mounted in the H direction in this order, a plurality of LED boards 13 c are arranged in the V direction with a simple configuration. It is possible to obtain the above-described effect that LEDs 12a and 12b having different lights are alternately arranged in the H direction, and different luminance unevenness is alternately formed in the H direction so that the bright line unevenness and the bright spot unevenness are not easily recognized.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to the drawings. In addition, the same member number is attached to the same structure as Embodiment 1 or 2, and the description is abbreviate | omitted.

  FIG. 6A is a plan view of the backlight 3 of the liquid crystal display device 1 of the present embodiment, and FIG. 6B schematically shows luminance unevenness when the backlight 3 is viewed from the diffusion plate 15 side. FIG. In FIG. 6A, illustration of the diffusing lens 14, the diffusing plate 15, the optical sheet 16, and the reflecting sheet 17 is omitted for convenience.

  In the present embodiment, the plurality of LED boards 13 includes a plurality of LED boards 13d (first mounting board) and a plurality of LED boards 13e (second mounting board). On the LED substrate 13d, the LEDs 12a having the light distribution A and the LEDs 12b having the light distribution B are arranged alternately in the H direction. The light distribution A and the light distribution B are the same as those described in the first or second embodiment.

  On the LED board 13e, the LEDs 12a and the LEDs 12b are alternately arranged in the H direction, but the arrangement order of these LEDs 12a and 12b is opposite to that of the LED board 13d. The LED substrates 13d and 13e are alternately arranged in the V direction. Thus, the LEDs 12a and 12b mounted on the LED boards 13d and 13e are arranged on the bottom plate 11a so as to be alternately arranged in both the H direction and the V direction, and both the H direction and the V direction are arranged. Will be mixed.

  As in the present embodiment, the LEDs 12a and 12b having different light distributions are mixed in both the H direction and the V direction, whereby different luminance unevenness due to the LEDs 12a and 12b is mixed in both directions. For this reason, the luminance unevenness due to the LED 12a (or LED 12b) having the same light distribution is not continuously arranged over a wide range in both directions, and the bright line unevenness or the bright spot unevenness caused by the luminance unevenness continues over a wide range in both directions. There is no line. Therefore, it is possible to make it difficult for the luminance unevenness of the individual LEDs 12a and 12b to be visually recognized as bright line unevenness or bright spot unevenness.

  In particular, the LEDs 12a and 12b having different light distributions are arranged so as to be alternately arranged in both the H direction and the V direction. Therefore, the luminance unevenness of the LED 12a (or LED 12b) having the same light distribution continues in both directions. And never line up. Accordingly, it is possible to reliably make it difficult to visually recognize the luminance unevenness of the individual LEDs 12a and 12b as bright line unevenness or bright spot unevenness.

  Further, by using two types of LED boards 13 in which the arrangement order of the LEDs 12a and 12b in the H direction is opposite, that is, the LED board 13d and the LED board 13e, these LED boards 13d and 13e are alternately arranged in the V direction. By arranging the LEDs 12a and 12b with different light distributions alternately in both the H and V directions, different brightness unevenness is formed alternately in both directions, making it difficult to see bright line unevenness and bright spot unevenness. It is possible to obtain the effect described above.

  In each of the above embodiments, when LEDs 12a and 12b having different light distributions are mixed in at least one direction of the H direction and the V direction, the LEDs 12a and 12b are alternately mixed and mixed one by one. For example, two of these LEDs 12a and 12b may be alternately arranged and mixed, or the other LED 12b may be mixed with every other LED 12a.

  In each of the above-described embodiments, two types of LEDs 12a and 12b are used as the point light sources having different light distributions. However, using LEDs having three or more types of light distributions, These may be mixed in at least one direction of the H direction and the V direction.

  The illumination device of the present invention can be used as a backlight for illuminating a liquid crystal panel of a liquid crystal display device, for example.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Liquid crystal panel 3 Backlight (illumination device)
11a Bottom plate 12 LED (point light source, light emitting diode)
12a LED (point light source, light emitting diode)
12b LED (point light source, light emitting diode)
13 LED board (mounting board)
13a LED board (first mounting board)
13b LED board (second mounting board)
13c LED board (mounting board)
13d LED board (first mounting board)
13e LED board (second mounting board)
14 Diffuser lens 15 Diffuser A Light distribution (first light distribution)
B Light distribution (second light distribution)
H First direction V Second direction

Claims (7)

A plurality of point light sources are two-dimensionally arranged on a bottom plate and emit light in a plane shape in a direction facing the bottom plate,
The plurality of point light sources includes point light sources different from each other in light distribution,
The point light sources having different light distributions are mixed in at least one of the first direction and the second direction perpendicular to each other in a plane along the bottom plate ,
The point light sources having different light distributions are alternately arranged in at least one of the first direction and the second direction,
Each of the plurality of point light sources is disposed on the substrate via any of a plurality of mounting substrates,
On the plurality of mounting boards, a point light source having a first light distribution and a point light source having a second light distribution different from the first light distribution are all in the same order in the first direction. They are arranged so that they line up alternately.
The plurality of mounting boards are arranged side by side in the second direction. A plurality of point light sources are two-dimensionally arranged on a bottom plate and emit light in a plane shape in a direction facing the bottom plate,
The plurality of point light sources includes point light sources different from each other in light distribution,
The point light sources having different light distributions are mixed in at least one of the first direction and the second direction perpendicular to each other in a plane along the bottom plate,
The point light sources having different light distributions are alternately arranged in at least one of the first direction and the second direction,
Each of the plurality of point light sources is disposed on the substrate via any of a plurality of mounting substrates,
The plurality of mounting boards are:
A plurality of first light sources in which a point light source having a first light distribution and a point light source having a second light distribution different from the first light distribution are arranged alternately in the first direction. Mounting board,
The point light sources having the first light distribution and the point light sources having the second light distribution are arranged alternately in the first direction, and the arrangement order of these point light sources is the A plurality of second mounting boards that are opposite to the first mounting board,
The lighting device, wherein the plurality of first and second mounting boards are alternately arranged in the second direction. Each of these point light sources is comprised with the light emitting diode, The illuminating device of Claim 1 or 2 characterized by the above-mentioned. The lighting device according to claim 3, wherein the light emitting diode emits white light. 5. The illumination device according to claim 1, further comprising a diffusing lens that is provided corresponding to each of the plurality of point light sources and diffuses light emitted from each point light source. 6. The illumination device according to claim 5, further comprising a diffusion plate that diffuses light incident through the diffusion lens corresponding to each of the plurality of point light sources. A lighting device according to any one of claims 1 to 6;
A liquid crystal display device comprising: a liquid crystal panel that performs display by modulating light supplied from the illumination device.

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