Luminaire

Abstract

To provide a luminaire capable of suppressing luminance unevenness.SOLUTION: A luminaire includes: a plurality of light sources arranged side by side in a line direction and a row direction in one in-plane; a substrate mounting the plurality of light sources; and a reflection member arranged so as to cover a mounting surface of the substrate. The reflection member includes: a plurality of insertion holes where the light sources are inserted; and a plurality of wall parts erected so as to surround the insertion holes. The in-plane of the reflection member is partitioned into a plurality of reflection regions in a lattice-like manner by the plurality of wall parts. The plurality of light sources is disposed inside one reflection region respectively. Out of the plurality of reflection regions arranged in a lattice-like manner, a plurality of outside reflection regions positioned on the outer periphery has a narrower area than the inside reflection region positioned inside the outside reflection regions.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a lighting device. [Background technology]

[0002] Conventionally, a so-called direct backlight device, in which light sources are arranged over the entire back surface of a liquid crystal panel, has been known as an illumination device used in a liquid crystal display device, and an example of such a device is disclosed in Patent Document 1. The illumination device described in Patent Document 1 includes a reflecting wall having a horizontal portion with insertion holes through which a plurality of light-emitting elements are individually inserted, and an inclined portion surrounding each of the light-emitting elements inserted into the insertion holes. In a plan view, the inclined portion of the reflecting wall has a shape that surrounds the light-emitting elements in a lattice pattern. With this configuration, the reflecting wall tends to uniformly direct light emitted from the light-emitting elements toward the liquid crystal panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 066209 Summary of the Invention [Problem to be solved by the invention]

[0004] The reflective wall described above directs light from the light-emitting elements toward the liquid crystal panel, while also propagating a certain amount within the plane. The outer periphery (frame portion) of the backlight device has fewer light-emitting elements than the central portion, and the amount of light propagated from the peripheral light-emitting elements is small. Therefore, the brightness of the outer periphery of the backlight device tends to decrease, and when the backlight device has a rectangular shape in plan view, the corners tend to be the darkest.

[0005] The technology described in this specification was developed based on the above circumstances, and aims to suppress brightness unevenness in lighting devices. [Means for solving the problem]

[0006] (1) A lighting device according to the present technology includes a plurality of light sources arranged in rows and columns on one surface, a substrate on which the plurality of light sources are mounted, and a reflective member arranged to cover the mounting surface of the substrate, the reflective member having a plurality of insertion holes through which the light sources are inserted and a plurality of wall portions erected to surround each of the insertion holes, the surface of the reflective member being partitioned in a grid pattern by the plurality of wall portions into a plurality of reflective areas, the plurality of light sources being arranged inside one of the reflective areas, and the outer reflective areas located on the outer periphery of the plurality of reflective areas arranged in a grid pattern having a smaller area than the inner reflective areas located inside the outer reflective areas.

[0007] (2) In addition to the above (1), the lighting device may further include a configuration in which the plurality of light sources are arranged at the same pitch, are disposed in the center of each of the inner reflective areas, and are biased toward the outer periphery of the reflective member in each of the outer reflective areas.

[0008] (3) In addition to the above (1), the lighting device may be configured such that each of the plurality of light sources is disposed in a central portion within each of the reflective areas.

[0009] (4) In addition to any one of (1) to (3) above, the lighting device may have an inclined wall portion such that the reflective area widens from the substrate side toward the tip side in the protruding direction of the wall portion.

[0010] (5) In addition to the above (4), the lighting device may be configured such that the wall portion of the outer reflective area has a larger inclination angle with respect to the substrate than the wall portion of the inner reflective area.

[0011] (6) In addition to any one of (1) to (5) above, the lighting device may be configured such that a higher power is applied to the light source disposed in the outer reflective area compared to the light source disposed in the inner reflective area.

[0012] (7) In addition to any one of (1) to (6) above, the lighting device may be configured such that the light source disposed in the outer reflective area has a higher luminous flux than the light source disposed in the inner reflective area.

[0013] (8) In addition to any one of (1) to (7) above, the lighting device may be configured such that the light source disposed in the outer reflective area has a lower voltage than the light source disposed in the inner reflective area. [Effects of the Invention]

[0014] According to the present technology, it is possible to suppress uneven brightness in a lighting device. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is an exploded perspective view of a liquid crystal display device including a backlight device according to a first embodiment. [Figure 2] 2 is a partially enlarged cross-sectional view of the liquid crystal display device taken along line II in FIG. 1. [Figure 3] Plan view of the LED and LED board [Figure 4] A perspective view of an LED, an LED substrate, and a reflective member [Figure 5] Plan view of the LED, LED board, and reflective member [Figure 6] Partially enlarged plan view of the LED, LED board, and corners of the reflective member [Figure 7] II-II cross section of Figure 6 [Figure 8] III-III cross section of Figure 6 [Figure 9] 10 is an enlarged plan view of a portion near a corner of an LED, an LED substrate, and a reflecting member according to a modified example. [Figure 10] IV-IV cross section of Figure 9 [Figure 11] V-V cross section of Figure 9 [Figure 12] 1 is a plan view of an LED and an LED substrate according to a second embodiment; [Figure 13] Plan view of the LED, LED board, and reflective member [Figure 14] Partially enlarged plan view of the LED, LED board, and corners of the reflective member [Figure 15] VI-VI cross section of Figure 14 [Figure 16] Cross section VII-VII of Figure 14 [Figure 17] FIG. 10 is a diagram showing power distribution in each dimming region of Example 2. [Figure 18] FIG. 10 is a diagram showing the change in luminance with respect to the distance from the corner in Example 1 and Example 2. [Figure 19] FIG. 10 is a diagram showing changes in luminance of the backlight device according to the first embodiment. [Figure 20] FIG. 10 is a diagram showing changes in luminance of the backlight device of Comparative Example 1. [Figure 21] 10 is a partially enlarged cross-sectional view of an LED, an LED substrate, and a reflecting member according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Embodiment 1> A first embodiment will be described with reference to Figs. 1 to 8. In this embodiment, a liquid crystal display device 10 including a backlight device (an example of a lighting device) 30 will be illustrated. Each drawing shows an X-axis, a Y-axis, and a Z-axis, and each axis direction is drawn so as to be a common direction in each drawing. In addition, in the Z-axis direction, the liquid crystal panel 20 side is the front side, and the backlight device 30 side is the back side.

[0017] As shown in Fig. 1, the liquid crystal display device 10 includes a liquid crystal panel 20 that displays images, a backlight device 30 that irradiates light onto the liquid crystal panel 20, and a bezel 14. The liquid crystal panel 20 is sandwiched between the bezel 14 and a frame 45 (described later) of the backlight device 30, with a display surface 20A capable of displaying images facing outward. The liquid crystal panel 20, the backlight device 30, and the liquid crystal display device 10 in this embodiment are all horizontally long rectangular in shape, with the long side aligned with the X-axis direction, the short side aligned with the Y-axis direction, and the thickness aligned with the Z-axis direction in each drawing. However, the illustrated shape is merely an example, and a vertically long rectangular shape may also be used.

[0018] 1, the bezel 14 is a support member disposed on the front side of the liquid crystal panel 20. The bezel 14 extends along the outer periphery of the front side of the liquid crystal panel 20, and constitutes the appearance of the front side of the liquid crystal display device 10. The bezel 14 is made of, for example, a metal with excellent rigidity (stainless steel, aluminum, etc.).

[0019] 1 and 2, the backlight device 30 includes a plurality of LEDs (an example of a light source) 52, an LED board 51 (an example of a board) on which the LEDs 52 are mounted, a reflective member 60, a chassis 40, a plurality of types of optical sheets 33, and a frame 45. The LEDs 52 are arranged in a planar array on the back side (bottom side) of the liquid crystal panel 20, and the backlight device 30 is a so-called direct type.

[0020] The chassis 40 is shaped like a shallow rectangular tray that is open toward the light-emitting side (front side, liquid crystal panel 20 side), and has an LED substrate 51 (see FIG. 2) installed on its bottom. The chassis 40 is made of resin such as white polycarbonate. The frame 45 is frame-shaped and made of metal such as stainless steel or aluminum.

[0021] The bezel 14, frame 45, and chassis 40 integrally hold the liquid crystal panel 20 and backlight device 30. Tape-like members may be attached to the bezel 14 and frame 45 as appropriate for fixing and light blocking. The bezel 14 and frame 45 may be non-frame-shaped, and only one of them may be provided.

[0022] 1, the optical sheet 33 has a horizontally long rectangular shape, and is disposed between the reflecting member 60 and the liquid crystal panel 20 to impart a predetermined optical effect to the light from the LEDs 52. A wide variety of optical sheets 33 are known, and one or more types may be used as appropriate depending on the intended use of the liquid crystal display device 10.

[0023] For example, using a light diffusion sheet as the optical sheet 33 can impart a diffusing effect to the light, improving in-plane uniformity. The thickness of the light diffusion sheet is, for example, in the range of about 30 μm to about 3 mm. Furthermore, using a brightness enhancement sheet as the optical sheet 33 can impart a condensing effect to the emitted light, increasing the front brightness. For example, 3M's BEF (Brightness Enhancement Film) (registered trademark) and DBEF (Dual Brightness Enhancement Film) (registered trademark) can be used as the brightness enhancement sheet. Other specific examples of the optical sheet 33 include a dichroic sheet (dichroic filter), a turning lens, a prism sheet (an optical sheet having a prism or lens shape, excluding brightness enhancement sheets and turning lenses), and a light diffusion sheet.

[0024] As shown in Fig. 3, the LEDs 52 are arranged in a grid (matrix) on the front main surface (mounting surface 51A) of the rectangular LED substrate 51 at equal intervals (same pitch) in the X-axis direction (row direction) and the Y-axis direction (column direction). The LEDs 52 are rectangular parallelepipeds, with their bottom surfaces located on the mounting surface 51A and their upper surfaces opposite the bottom surfaces serving as light-emitting surfaces 52A, making them so-called top-emitting (top-view) LEDs (see Fig. 2). The optical axis of the LEDs 52 (the direction in which light travels with the highest (peak) luminous intensity) is in the Z-axis direction.

[0025] The LED 52 is preferably a white-emitting type, and may be a miniaturized package such as a CSP (Chip Scale Package) or flip-chip type. The LED 52 may also be a so-called mini LED or micro LED, with a light-emitting surface 52A having an area of ​​approximately 1.0 mm2 or less. When a monochromatic LED (e.g., a blue-emitting type) is used as the LED 52, a wavelength conversion sheet (color conversion sheet) is used in combination to emit white composite light (mixed light). The wavelength conversion sheet may be of any type, as long as it can convert the wavelength of primary light into secondary light within a different wavelength range. For example, a wavelength conversion sheet containing a quantum dot phosphor, inorganic phosphor, or organic phosphor may be used.

[0026] The LED substrate 51 has a horizontally long rectangular shape and is configured such that a wiring pattern made of a conductive material is formed on a base material. The LED substrate 51 may be, for example, an aluminum substrate or a glass epoxy substrate, but may also be a flexible substrate (FPC) or the like that has excellent flexibility.

[0027] 3, the mounting surface 51A of the LED substrate 51 is divided into a plurality of dimming areas (segment areas) DA arranged in a matrix with no gaps between them. In this embodiment, each dimming area DA is rectangular and includes one LED 52. Each dimming area DA has a size large enough to include at least one LED 52.

[0028] In this embodiment, the dimming area DA1 including the outer peripheral edge of the LED substrate 51 is smaller in area than the dimming area DA2 (dimming area DA not including the outer peripheral edge of the LED substrate 51) inside it. In other words, the distance (M1 in the X-axis direction, N1 in the Y-axis direction) from the LEDs 52 arranged adjacent to the outer peripheral edge (edge) of the LED substrate 51 to the outer peripheral edge of the LED substrate 51 is smaller than half the pitch (P1 in the X-axis direction, Q1 in the Y-axis direction) of the LEDs 52 (N1 <P1 / 2,M1<Q1 / 2)。

[0029] Driving power is supplied to the LEDs 52 from an external power source via a wiring pattern formed on the LED substrate 51. The wiring pattern and the like of the backlight device 30 are configured so that local dimming drive is performed, in which the driving power supplied to the LEDs 52 is controlled independently for each dimming area DA. The driving power is controlled by a control unit provided in the liquid crystal display device 10. This makes it possible to locally adjust the luminous flux of the LEDs 52 for each dimming area DA. The backlight device 30 and the liquid crystal display device 10 are capable of high-definition, high-contrast brightness adjustment and low power consumption through local dimming drive.

[0030] The reflective member 60 is placed on the mounting surface 51A of the LED substrate 51 and is fixed in close contact so as to cover the entire mounting surface 51A from the front side. As shown in Figures 4 to 6, the reflective member 60 has a horizontally elongated rectangular shape in a plan view, and has four corners 60A, 60B, 60C, and 60D and four sides 60E, 60F, 60G, and 60H. The reflective member 60 is made of a resin such as white polycarbonate that has excellent light reflectance, and each part is integrally formed.

[0031] The reflecting member 60 has a plurality of insertion holes 61 and a plurality of wall portions 65. The insertion holes 61 have a shape and size that allow at least one LED 52 to be inserted therethrough. Each insertion hole 61 according to this embodiment is rectangular and large enough to insert one LED 52 therethrough. In the illustration, the LED 52 and the mounting surface 51A of the LED substrate 51 in the vicinity thereof are exposed to the front side through the insertion holes 61, but the insertion holes 61 may be formed large enough to insert only the light-emitting surface 52A of the LED 52 therethrough.

[0032] If a portion of the mounting surface 51A of the LED substrate 51 is exposed through the insertion hole 61, a reflective sheet that covers this exposed portion from the front side may be provided between the mounting surface 51A and the reflective member 60. By providing the reflective sheet, the reflectivity can be further improved. For example, a polyester-based or PET-based white resin sheet such as ESR (Enhanced Specular Reflector) can be used as the reflective sheet.

[0033] The wall portion 65 of the reflecting member 60 is formed to stand and surround at least one insertion hole 61. The wall portion 65 according to the present embodiment surrounds each insertion hole 61 and each LED 52 inserted therein, but the wall portion 65 may surround multiple insertion holes 61 or may insert multiple LEDs 52 into each insertion hole 61, thereby surrounding multiple LEDs 52.

[0034] The surface of the reflecting member 60 is divided into a plurality of reflective areas RA in a grid pattern by walls 65. The reflective areas RA are preferably provided so as to separate the dimming areas DA of the local dimming drive described above. The reflective area RA according to this embodiment is provided so as to separate one dimming area DA, and the reflective area RA and the dimming area DA are substantially the same size.

[0035] 4 and 5, among the multiple reflective regions RA, the reflective regions RA located at corners 60A, 60B, 60C, and 60D of the reflective member 60 are referred to as first reflective regions RA1 (an example of an outer reflective region). Furthermore, among the multiple reflective regions RA, the reflective regions RA (including sides 60E and 60G) arranged at the outermost periphery and aligned in the X-axis direction (row direction) other than the first reflective region RA1 are referred to as second reflective regions RA2 (an example of an outer reflective region). Similarly, among the multiple reflective regions RA, the reflective regions RA (including sides 60F and 60H) arranged at the outermost periphery and aligned in the Y-axis direction (column direction) other than the first reflective region RA1 are referred to as third reflective regions RA3 (an example of an outer reflective region). Furthermore, among the multiple reflective regions RA, the reflective region RA located in the center (inside the outermost periphery) other than the first reflective region RA1, second reflective region RA2, and third reflective region RA3 is referred to as fourth reflective region RA4 (an example of an inner reflective region).

[0036] In the reflecting member 60 of the present embodiment, the first reflection region RA1, the second reflection region RA2, and the third reflection region RA3 located at the outermost periphery are set such that their areas in a plan view are smaller than those of the fourth reflection region RA4 located at the central portion (inside the outermost periphery). Specifically, as shown in FIG. 5, the dimension x2 in the X-axis direction of the first reflection region RA1 and the third reflection region RA3 located at the ends in the X-axis direction is set to be smaller than the dimension x1 in the X-axis direction of the second reflection region RA2 and the fourth reflection region RA4 located on the central side in the X-axis direction (x2 < x1). Also, the dimension y2 in the Y-axis direction of the first reflection region RA1 and the second reflection region RA2 located at the ends in the Y-axis direction is set to be smaller than the dimension y1 in the Y-axis direction of the third reflection region RA3 and the fourth reflection region RA4 located on the central side in the Y-axis direction (y2 < y1). It can also be said that the pitch of the reflection regions RA1, RA2, RA3 located at the outermost periphery is smaller than the pitch of the reflection region RA4 located at the central portion.

[0037] In the present embodiment, x1 = 8.25 mm, x2 = 5.7 mm, y1 = 8.25 mm, and y2 = 5.2 mm. With such a configuration, the areas S of the first reflection region RA1, the second reflection region RA2, the third reflection region RA3, and the fourth reflection region RA4 in a plan view are such that the area S1 of the first reflection region < the area S2 of the second reflection region < the area S3 of the third reflection region < the area S4 of the fourth reflection region. Note that as the ratio of the dimensions, it is preferable that x2 / x1 = 0.3 to 0.7 and y2 / y1 = 0.3 to 0.7.

[0038] By thus setting the areas of the reflection regions RA1, RA2, RA3 arranged at the outermost periphery to be smaller than the area of the reflection region RA4 at the central portion in a plan view, the luminance of the light confined in the outermost reflection regions RA1, RA2, RA3 can be relatively increased compared to the luminance of the light in the central reflection region RA4. That is, the luminance of the outer peripheral portion, which was conventionally low in the backlight device 30, is improved, and luminance unevenness is suppressed.

[0039] As described above, the LEDs 52 are arranged in a lattice (matrix) at equal intervals in the X-axis direction (row direction) and the Y-axis direction (column direction) (pitch P1 in the X-axis direction, and pitch Q1 in the Y-axis direction, where P1=x1 and Q1=y1). Therefore, the LEDs 52 arranged in the fourth reflective region RA4 are arranged in the center of each region, while the LEDs 52 arranged in the first reflective region RA1, the second reflective region RA2, and the third reflective region RA3 are arranged in positions biased toward the outer periphery of the reflective member 60 from the center of each region (see FIGS. 5 and 6).

[0040] Furthermore, arranging multiple LEDs 52 at the same pitches P1 and Q1 in this manner not only makes it easier to achieve the same brightness within the light-emitting surface of the backlight device 30 when a constant power is supplied to the LEDs 52, but also makes it easier to calculate the power input to each LED 52 according to the input image in local dimming, which changes the light-emitting intensity of the LEDs 52 according to the displayed image, which is advantageous in that it makes it possible to reduce the circuit size.

[0041] As shown in Figures 7 and 8, each wall 65 that divides each of the above-mentioned reflection areas RA into a grid pattern protrudes from the LED substrate 51 side toward the front side with a mountain-shaped cross section. Each wall surface 66 of the four wall portions 65 that surround one LED 52 and form one reflection area RA forms an inclined surface that slopes and widens in the width direction from the LED substrate 51 side toward the opposite side (upward) of the LED substrate 51 so that each reflection area RA expands in diameter. In other words, each reflection area RA is surrounded by four trapezoidal inclined surfaces (wall surfaces 66) in the shape of an inverted quadrangular pyramid, surrounding each LED 52 (see Figures 4 to 6). By such inclined wall surfaces 66, light emitted from each LED 52 and reaching the wall surfaces 66 is reflected toward the front side.

[0042] The tip 67 of the wall portion 65 is chamfered and disposed with a small gap G between it and the rear surface of the optical sheet 33, as shown in FIG. 2 . Alternatively, the tip 67 of the wall portion 65 may be in contact with the rear surface of the optical sheet 33 without any gap. Providing the gap G facilitates the exchange of light emitted from the LEDs 52 surrounded by the wall portion 65 and light emitted from the LEDs 52 adjacent to the LEDs 52, i.e., light between adjacent reflective regions RA. However, even if there is no gap G, the light between adjacent reflective regions RA exchanges to a certain extent before passing through the optical sheet 33 and being emitted to the liquid crystal panel 20, spreading within the plane.

[0043] In the reflecting member 60 of this embodiment, the wall surfaces 66 of the wall portion 65 are set at different inclination angles with respect to the mounting surface 51A depending on the above-mentioned reflection area RA. Specifically, in the fourth reflection area RA4 that is disposed on the inner side of the plurality of reflection areas RA, the wall surfaces 66A of the four wall portions 65 surrounding each LED 52 are all set at θ1 = 63 degrees with respect to the mounting surface 51A of the LED substrate 51.

[0044] On the other hand, in the second reflection area RA2 and the third reflection area RA3, as shown in Figures 6 to 8, the angle of the wall surfaces 66A other than one wall surface 66B arranged on the outer periphery of the reflection member 60 is θ1 = 63 degrees, the same as in the fourth reflection area RA4, but the angle of the wall surface 66B arranged on the outer periphery of the reflection member 60 is θ2 = 78 degrees with respect to the mounting surface 51A of the LED substrate 51, which is set to an angle larger than θ1 (θ2 > θ1).

[0045] Furthermore, in the first reflection area RA1, the angle of the wall surfaces 66A other than the two wall surfaces 66B arranged on the outer periphery of the reflection member 60 is θ1 = 63 degrees, the same as in the fourth reflection area RA4, but the angle of the two wall surfaces 66B arranged on the outer periphery of the reflection member 60 is θ2 = 78 degrees with respect to the mounting surface 51A of the LED substrate 51 (θ2 > θ1).

[0046] In this way, in the outermost reflective regions RA1, RA2, and RA3, by making the inclination angle θ2 of the wall surface 66B arranged on the outer periphery of the reflective member 60 steeper than the inclination angle θ1 of the other wall surface 66A (the wall surface arranged on the inner side), it is possible to more strongly direct the light emitted from the LEDs 52 toward the front side. Note that the difference in the inclination angles is preferably 10 degrees or more (θ2 - θ1 > 10°). If the difference is 10 degrees or more, the difference in brightness becomes large.

[0047] Next, the effects will be described. The backlight device 30 of this embodiment includes a plurality of LEDs 52 arranged in rows and columns on one surface, an LED substrate 51 on which the plurality of LEDs 52 are mounted, and a reflective member 60 arranged to cover a mounting surface 51A of the LED substrate 51. The reflective member 60 has a plurality of insertion holes 61 through which the LEDs 52 are inserted and a plurality of wall portions 65 erected to surround each insertion hole 61. The surface of the reflective member 60 is partitioned into a plurality of reflective areas RA in a lattice pattern by the plurality of walls 65, and the plurality of LEDs 52 are each arranged inside one of the reflective areas RA. Among the plurality of reflective areas RA arranged in a lattice pattern, each of a plurality of reflective areas RA1, RA2, and RA3 located on the outer periphery has an area smaller than each of a plurality of reflective areas RA4 located inside the reflective areas RA1, RA2, and RA3.

[0048] According to the above configuration, in the reflective areas RA1, RA2, and RA3 on the outer periphery of the reflective area RA, where brightness is likely to be low, the light emitted from each of the reflective areas RA1, RA2, and RA3 is stronger than in the conventional configuration in which the reflective areas are all of the same area, thereby suppressing brightness unevenness throughout the backlight device 30.

[0049] The multiple LEDs 52 are arranged at the same pitch (P1 in the X-axis direction, Q1 in the Y-axis direction), and are arranged in the center of the fourth reflective area RA4, and are also arranged biased toward the outer periphery of the reflective member 60 in the first reflective area RA1, second reflective area RA2, and third reflective area RA3, which are arranged at the outermost periphery.

[0050] Moreover, the wall portion 65 has an inclined shape in which the reflection area RA widens from the LED substrate 51 side toward the tip side (upward) in the protruding direction of the wall portion 65. With this configuration, the light emitted from the LED 52 can be directed upward.

[0051] Furthermore, a portion (wall surface 66B) of the wall portion 65 of the reflective regions RA1, RA2, and RA3 arranged on the outermost periphery has a larger inclination angle (θ2>θ1) with respect to the LED substrate 51 than a wall surface 66A of the wall portion 65 of the reflective region R4 arranged on the inner side. With this configuration, the light emitted from the LEDs 52 can be more strongly directed upward in the reflective regions RA1, RA2, and RA3 on the outermost periphery, where brightness is likely to be low.

[0052] <Modification of the First Embodiment> Next, modifications of Example 1 will be described with reference to Figures 9 to 11. In the following, for the reflecting member 70, components similar to those of the reflecting member 60 of Embodiment 1 will be assigned reference numerals obtained by adding 10 to the reference numerals of Embodiment 1, and only the different components will be described.

[0053] In the modified reflective member 70, in the first reflective area RA1, the second reflective area RA2, and the third reflective area RA3, the angle of the wall surfaces 76B arranged on the outer periphery of the reflective member 70 is formed at a right angle with respect to the mounting surface 51A of the LED substrate 51. The angle of the wall surfaces 76A other than the wall surfaces 76B arranged on the outer periphery of the reflective member 70 is set to θ1 = 63 degrees, the same as the wall surfaces 76A in the fourth reflective area RA4.

[0054] This configuration also makes it possible to improve the brightness on the outer periphery of the backlight device 30, which has traditionally had low brightness, and to suppress brightness unevenness.

[0055] <Embodiment 2> Next, a second embodiment will be described with reference to Figures 12 to 16. Note that only the configurations different from the first embodiment will be described below, and the same configurations as those in the first embodiment will be assigned reference numerals that are 100 larger than the reference numerals in the first embodiment, and redundant description will be omitted.

[0056] In the backlight device 130 of this embodiment, the positions of the LEDs 152 arranged in the dimming region DA1 including the outer peripheral edge of the LED substrate 151 are different from those in the first embodiment. Specifically, as shown in FIG. 12, the dimming region DA1 including the outer peripheral edge of the LED substrate 151 has a smaller area compared to the inner dimming region DA2, and the LEDs 152 arranged in the dimming region DA1 are arranged at the central portions in each dimming region DA, similarly to the LEDs 152 arranged in the dimming region DA2 (see FIG. 12). That is, the pitches of the LEDs 152 at both ends in the row direction and the column direction (pitch P2 in the X-axis direction and pitch Q2 in the Y-axis direction) are smaller than the pitch of the LEDs 152 at the central portion (pitch P1 in the X-axis direction and pitch Q1 in the Y-axis direction) (P1 > P2, Q1 > Q2).

[0057] As shown in FIG. 13, in the reflection member 160 of this embodiment as well, the first reflection region RA1, the second reflection region RA2, and the third reflection region RA3 located at the outermost periphery are set to have a smaller area when viewed in plan compared to the fourth reflection region RA4 located at the central portion (inside the outermost periphery). Specifically, as shown in FIG. 14, the dimension x4 in the X-axis direction of the first reflection region RA1 and the third reflection region RA3 is smaller than the dimension x1 in the X-axis direction of the second reflection region RA2 and the fourth reflection region RA4 (x4 < x1). Also, the dimension y4 in the Y-axis direction of the first reflection region RA1 and the second reflection region RA2 is smaller than the dimension y1 in the Y-axis direction of the third reflection region RA3 and the fourth reflection region RA4 (y4 < y1).

[0058] In the second and third reflection areas RA2 and RA3, the wall portions 165 constituting the reflection areas RA of the reflection member 160 of this embodiment have wall surfaces 166B arranged on the outer periphery of the reflection member 160 and the opposing wall surfaces 166B arranged at an angle of θ2 = 78 degrees with respect to the mounting surface 151A of the LED substrate 151. In the second and third reflection areas RA2 and RA3, the wall surfaces 166A arranged in a direction intersecting the outer periphery of the reflection member 160 have an angle of θ1 = 63 degrees, the same as the wall surfaces 166A of the fourth reflection area (see FIGS. 13 to 16).

[0059] Furthermore, in the first reflection area RA1, all of the four wall surfaces 166B are angled at θ2=78 degrees with respect to the mounting surface 151A of the LED substrate 151 (θ2>θ1).

[0060] Even with this configuration, it is possible to improve the brightness on the outer periphery of the backlight device 130, and to obtain a backlight device 130 with reduced brightness unevenness.

[0061] <Embodiment 3> The backlight device of embodiment 3 has the same configuration as embodiment 1, but also distributes the power supplied to each LED. It is preferable that the power be distributed so that the first reflective area RA1, which is most likely to have low brightness, receives the highest power and the fourth reflective area RA4, which provides high brightness, receives the lowest power. By combining the power distribution with the configuration of embodiment 1, it is possible to further reduce brightness unevenness.

[0062] <Embodiment 4> The backlight device of embodiment 4 has the same configuration as embodiment 1, but also has LEDs with high luminous flux installed at the outermost periphery. LEDs vary in luminous flux depending on their performance, so by using high-performance products at the outermost periphery, the brightness at the outermost periphery can be further increased.

[0063] High-luminous flux LEDs can be used for the entire outermost reflective area, or just the corner reflective areas. High-luminous flux LEDs are usually expensive, so using them only in the corners can reduce manufacturing costs.

[0064] <Embodiment 5> The backlight device of embodiment 5 has the same configuration as embodiment 1, but with low-voltage LEDs installed on the outermost periphery. Low-voltage LEDs can achieve higher brightness with the same current value. Low-voltage LEDs can be used for the entire outermost reflective area, or only for the corner reflective areas.

[0065] <Verification of the effects of the embodiment> (1) For the backlight device 30 obtained in the above embodiment 1 and a conventional backlight device (in which all reflective areas RA have the same area), the change in brightness with respect to the change in distance along the diagonal from one corner was measured (Example 1 and Comparative Example 1).

[0066] (2) Furthermore, for a backlight device with a power distribution similar to that of embodiment 3 and a backlight device with a power distribution similar to that of comparative example 1 (conventional configuration), the change in luminance with respect to the change in distance along the diagonal from one corner was measured (Example 2 and Comparative Example 2). The power distribution is as shown in Fig. 17, and the power ratio of the other reflective areas is shown numerically when the power of the first reflective area RA1 (corner dimming area) is set to 100.

[0067] (3) For a backlight device in which LEDs with high luminous flux (with an average luminous flux 1.19 times that of the LEDs used in Example 1) were installed at the outermost periphery as in Example 4, the change in brightness with respect to the change in distance along the diagonal from one corner was measured (Example 3).

[0068] (4) For a backlight device in which low-voltage LEDs (with an average voltage 0.88 times that of the LEDs used in Example 1) were installed at the outermost periphery as in Example 5, the change in brightness with respect to the change in distance along the diagonal from one corner was measured (Example 4).

[0069] The brightness distribution was measured using a Konica Minolta CA-2000 two-dimensional color luminance meter, and the brightness of the measurement point was calculated assuming that the brightness of the center of the backlight device 30 was 100%. The closer the brightness of the measurement point is to 100%, the smaller the difference in brightness from the center. It can be said that the closer the brightness is to 100% at the corners, where brightness is usually lowest, the higher the brightness uniformity within the light-emitting area.

[0070] The design values ​​of the backlight devices used in this example and the comparative example (conventional) are as follows (see FIG. 5).

[0071] X0=292mm Y0=109.5mm Number of reflection areas: 36 in the X-axis direction x 14 in the Y-axis direction x1=8.25mm y1=8.25mm x2=5.7mm y2=5.2mm x2 / x1=0.69 y2 / y1=0.63 x0 = 8.1 mm (length of the reflective area of ​​a conventional backlight device along the x-axis) y0 = 7.8 mm (length of the reflective area in the Y-axis direction of the conventional backlight device)

[0072] 18, in Example 1, the brightness of the outer periphery was improved overall compared to Comparative Example 1. In particular, the brightness of the outermost periphery (distance from the corner = 0 mm) was improved 1.6 times to 52%, compared to 32% in Comparative Example 1.

[0073] Furthermore, in Example 2, in which the power was distributed, the brightness in the peripheral area was further improved. In particular, the brightness at the outermost periphery increased from 52% in Example 1 to 69%, a 1.33-fold increase. In Comparative Example 2, the brightness also increased from 32% in Comparative Example 1 to 41%, a 1.28-fold increase. However, since the original brightness of Example 1 was higher, Example 2 achieved a higher brightness than Comparative Example 2. Figures 19 and 20 are diagrams visually showing the brightness uniformity of Example 1 and Comparative Example 1, and show that in Example 1, the brightness uniformity is improved in the peripheral area of ​​the backlight device.

[0074] Although it is possible to further increase the power distribution to improve the luminance uniformity, the larger the distribution, the greater the power consumption of the LED driver that supplies the power, so it is preferable to strike a balance. Example 2, which can improve the luminance uniformity with as small a power distribution as possible, can be said to be very preferable.

[0075] In addition, in Example 3, in which LEDs with large luminous flux were used on the outermost periphery, the brightness at the corners increased from 52% of Example 1 to 62%, a 1.19-fold increase.

[0076] Furthermore, in Example 4, in which low-voltage LEDs were used on the outermost periphery, the brightness at the corners increased from 52% of Example 1 to 78%, which was 1.5 times higher.

[0077] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0078] (1) In the above embodiment, the wall portion 65 is inclined relative to the mounting surface 51A of the LED substrate 51, but a configuration in which the wall portion is not inclined is also included in the technical scope.

[0079] (2) For example, as shown in Fig. 21, a configuration in which wall surfaces 266 of wall portions 265 of reflecting member 260 have the same inclination angle θ3 in all reflecting areas is also included in the technical scope.

[0080] (3) In the above embodiment, a lighting device using a top-emitting LED 52 was shown, but a side-emitting LED with a reflective surface formed on the top surface may also be used. Although the amount of luminous flux of a side-emitting LED is somewhat reduced, the lighting device can be made thinner by efficiently diffusing the light using a reflective wall.

[0081] (4) In the third and fourth embodiments, the LEDs with large luminous flux and the LEDs with low voltage are arranged over the entire surface, but they may be arranged only at the corners of the LED substrate.

[0082] (5) The pitch of the dimming areas DA and the number of LEDs 52 included in each dimming area DA can be changed as appropriate depending on the screen size of the liquid crystal panel 20, the intended use, and the required accuracy. [Explanation of symbols]

[0083] 30,130: Backlight device (lighting device) 51,151: LED board (board) 51A,151A: Mounting surface 52,152: LED (light source) 52A,152A: Light emitting surface 60,70,160,260: Reflective member 61,161: Insertion hole 65,165,265: Wall part 66,66A,66B,76A,76B,166A,166B,266: Wall surface DA: Dimming area RA: Reflective area RA1: 1st reflective area (outer reflective area) RA2: 2nd reflective area (outer reflective area) RA3: 3rd reflective area (outer reflective area) RA4: 4th reflective area (inner reflective area)

Claims

1. a plurality of light sources arranged in rows and columns on one surface; a substrate on which a plurality of the light sources are mounted; a reflecting member disposed so as to cover the mounting surface of the board, The reflecting member is a plurality of insertion holes through which the light sources are inserted; a plurality of wall portions erected so as to surround each of the insertion holes, The surface of the reflecting member is partitioned into a plurality of reflecting regions in a grid pattern by the plurality of wall portions, The plurality of light sources are each disposed inside one of the reflective areas, An illumination device, wherein an outer reflective area located on the outer periphery of the plurality of reflective areas arranged in a grid pattern has an area smaller than an inner reflective area located inside the outer reflective area.

2. The lighting device according to claim 1 , wherein the plurality of light sources are arranged at the same pitch, are arranged in the center of each of the inner reflective areas, and are arranged biased toward the outer periphery of the reflective member in each of the outer reflective areas.

3. The lighting device according to claim 1 , wherein each of the plurality of light sources is disposed in a central portion within each of the reflective areas.

4. The lighting device according to claim 1 , wherein the wall portion has an inclined shape such that the reflective area widens from the substrate side toward a tip end side in a protruding direction of the wall portion.

5. 5. The lighting device according to claim 4, wherein the wall portion of the outer reflective area has a larger inclination angle with respect to the substrate than the wall portion of the inner reflective area.

6. 3. The lighting device according to claim 1, wherein higher power is applied to the light source disposed in the outer reflective area than to the light source disposed in the inner reflective area.

7. 3. The lighting device according to claim 1, wherein the light source disposed in the outer reflective area has a higher luminous flux than the light source disposed in the inner reflective area.

8. 3. The lighting device according to claim 1, wherein the light source disposed in the outer reflective area has a lower voltage than the light source disposed in the inner reflective area.

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