JP2013247039A - Lighting apparatus and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting apparatus capable of irradiating light on an irradiation body so that luminance in a surface direction of the irradiation body may be uniform, and a display device having the lighting apparatus.SOLUTION: As for a backlight unit 1, a reflection member 118 has an auxiliary reflection part 1182, and the auxiliary reflection part 1182 surrounds a light-emitting part 111 and extends by inclining at a prescribed angle to an optical axis S of the light-emitting part 111. Then, in the auxiliary reflection parts 1182 forming an inverted V-shape of the neighboring light-emitting devices 11, a projection area of the auxiliary reflection parts 1182 on a far side to the center of a bottom part 131 is established to be larger than the projection area of the auxiliary reflection parts 1182 on a near side to the center of the bottom part 131 in the frame member 13.

Description

  The present invention relates to an illumination device that irradiates light on a back surface of a display panel, and a display device including the illumination device.

In the display panel, liquid crystal is sealed between two transparent substrates, and a voltage is applied to change the direction of liquid crystal molecules and change the light transmittance to optically display a predetermined image. Is done. In this display panel, since the liquid crystal itself is not a light emitter, for example, a cold cathode tube (CCFL) and a light emitting diode (LED: Light Emitting) are provided on the back side of the transmissive display panel.
A backlight unit that emits light using a diode as a light source is provided.

  In the backlight unit, a light source such as a cold cathode tube or LED is arranged on the bottom surface to emit light, and a light source such as a cold cathode tube or LED is arranged on the edge of a transparent plate called a light guide plate. There is an edge light type that emits light to the front surface by dot printing or pattern shape provided on the back surface through light from the light plate edge.

  LEDs have excellent characteristics such as low power consumption, long life, and reduced environmental impact by not using mercury, but they are expensive in price, and until the blue LED is invented, the white LED is The absence of the light source and the strong directivity led to a delay in the use of the backlight unit as a light source. However, in recent years, high color rendering high-intensity white LEDs have been rapidly spreading for lighting applications, and the LEDs have become cheaper. Accordingly, as a light source of a backlight unit, there has been a transition from a cold cathode tube to an LED. Progressing.

  Since the LED has strong directivity, the edge light type is more effective than the direct type from the viewpoint of irradiating light so that the luminance of the surface of the display panel is uniform in the surface direction. However, the edge light type backlight unit has a problem that heat generated by the light source is concentrated due to the light source being concentrated on the edge portion of the light guide plate, and the bezel portion of the display panel is enlarged. Arise. Furthermore, the edge light type backlight unit has a great restriction on partial dimming control (local dimming), which is attracting attention as a control method capable of improving the quality and power saving of a display image. There is a problem that it is not possible to control a small divided area where high quality and power saving can be achieved.

  Therefore, in a direct-type backlight unit that is advantageous for partial dimming control, even when an LED with strong directivity is used as the light source, light is irradiated onto the display panel so that the luminance is uniform. There are ongoing studies of possible ways to do this.

  For example, Patent Documents 1 and 2 disclose a backlight unit including a light emitting unit in which a plurality of LEDs that emit light are arranged and arranged, and a plurality of reflectors that are provided around each LED and reflect light. ing. Each reflector corresponding to each LED has a bottom part provided at the lower part of the LED, and a side wall part connected to the edge of the bottom part and surrounding the LED. In the backlight units disclosed in Patent Documents 1 and 2, the light emitted from the LED is reflected by a reflector to make the luminance of the display panel uniform.

Special table 2008-542994 gazette JP 2004-6317 A

  In a backlight unit in which a plurality of LEDs are aligned and arranged, for example, when attention is paid to one LED, one LED corresponding to an end portion in the surface direction of the display panel corresponds to one central portion in the surface direction of the display panel. There are fewer adjacent LEDs than two LEDs.

  In the backlight units disclosed in Patent Documents 1 and 2, each reflector corresponding to each LED is formed in the same shape and size, so that the amount of light reflected by each reflector is the same. It is. Therefore, the amount of light that is reflected by each reflector and reaches the display panel is less in the end portion where the number of LEDs adjacent to one LED is smaller than the central portion in the surface direction of the display panel, and as a result, There is a problem that the luminance in the surface direction of the display panel becomes non-uniform.

  The present invention solves such problems, and an illuminating device that can irradiate an irradiated object with light so that the luminance in the surface direction of the irradiated object is uniform, and the illuminating device. An object is to provide a display device provided.

The present invention includes a housing having a bottom portion;
A plurality of light emitting portions for emitting light, arranged in alignment at the bottom;
A reflecting member that is provided around each light emitting unit and reflects light emitted from the light emitting unit toward an irradiated body, and extends at an angle with respect to the optical axis of the light emitting unit. A reflective member having a first reflective part surrounding the light emitting part,
In adjacent reflecting members, the region portions of the first reflecting portion facing each other are located closer to the center portion of the bottom portion than the region portion of the first reflecting portion disposed at a position closer to the center portion of the bottom portion. The illumination device is characterized in that the area of the first reflecting portion disposed at a far position is large in projected area when projected in the optical axis direction.

  In the illumination device of the present invention, the projected area of the first reflecting portion of each reflecting member when projected in the optical axis direction increases stepwise from the center of the bottom toward the edge. It is characterized by.

  Moreover, in the illuminating device of this invention, in the adjacent reflective member, the area parts of the first reflecting part facing each other are closer to the area part of the first reflecting part arranged closer to the center part of the bottom part. The region portion of the first reflecting portion disposed at a position far from the central portion of the bottom portion is set so that the inclination angle with respect to the optical axis is increased.

In the illumination device of the present invention, the reflecting member further includes a second reflecting portion that extends in a direction perpendicular to the optical axis and has an outer shape that is a polygon when viewed in the optical axis direction,
The first reflecting part extends continuously from a side part of the second reflecting part.

The present invention also provides a display panel,
A display device comprising: the illumination device that irradiates light to the display panel.

  According to the present invention, a lighting device is provided around a plurality of light emitting units arranged in alignment at the bottom of a housing, and around each light emitting unit, and reflects light emitted from the light emitting units toward an irradiated body. A reflective member. The reflecting member has a first reflecting portion, and the first reflecting portion surrounds the light emitting portion and extends at a predetermined angle with respect to the optical axis of the light emitting portion. In the adjacent reflecting member, the region portions of the first reflecting portion that are opposed to each other are located on the first reflecting portion (center-side proximity-side first reflecting portion) disposed at a position close to the center portion of the bottom portion. The projected area when the area part of the first reflecting part (center part separating side first reflecting part) arranged at a position farther from the center part of the bottom part than the area part projects in the optical axis direction. It is set to be large.

  In the illuminating device of the present invention, in the adjacent reflecting member, the projected area when projected in the direction of the optical axis in the region portions of the first reflecting portion facing each other is larger than the region portion of the central-side proximity-side first reflecting portion. However, since the area part of the central part separation side first reflection part is larger, the amount of light reflected by the reflection member corresponding to each light emitting part is larger than that of the reflection member corresponding to the central part proximity side first reflection part. Also, the number of the reflecting members corresponding to the central part separating side first reflecting part is larger.

  Therefore, the amount of light reflected by each reflecting member corresponding to each light emitting unit and reaching the irradiated body is such that the number of light emitting sections adjacent to one light emitting section is small in the surface direction of the irradiated body. It can suppress that a part becomes fewer than a center part. That is, the amount of light that is reflected by each reflecting member corresponding to each light emitting unit and reaches the irradiated body can be made uniform in the surface direction of the irradiated body, and as a result, in the surface direction of the irradiated body. The brightness can be made uniform.

  According to the invention, the projected area of the first reflecting portion of each reflecting member when projected in the optical axis direction is set to increase stepwise from the bottom center to the edge. Has been. As a result, the amount of light reflected by each reflecting member corresponding to each light emitting unit and reaching the irradiated body can be made more effective and uniform in the surface direction of the irradiated body. The brightness in the body surface direction can be made uniform.

  Further, according to the present invention, in the adjacent reflecting members, the first reflecting portions arranged in positions close to the center portion of the bottom portion of the first reflecting portions facing each other (the first portion closer to the center portion) The region portion of the first reflecting portion (center portion separating side first reflecting portion) disposed at a position farther from the center portion of the bottom portion than the region portion of the reflecting portion has a larger inclination angle with respect to the optical axis. Is set to Thereby, in the adjacent reflecting member, the projected area when projected in the optical axis direction in the region portions of the first reflecting portion facing each other is more central than the region portion of the first reflecting portion near the center portion. It can be set so that the region portion of the separation-side first reflection portion is larger. For this reason, the amount of light reflected by the reflecting member corresponding to each light emitting unit is set so that the reflecting member corresponding to the central part separating side first reflecting part is more than the reflecting member corresponding to the central part adjacent side first reflecting part. Can do a lot.

  According to the invention, each reflecting member further has a second reflecting portion that extends in a direction perpendicular to the optical axis and whose outer shape when viewed in the optical axis direction is a polygonal shape. In the reflecting member having the second reflecting portion, the first reflecting portion is provided so as to extend continuously to the side portion of the second reflecting portion. Thereby, since the light emitted from the light emitting unit is reflected by the first reflecting unit and the second reflecting unit of the reflecting member, the light emitted from the light emitting unit can be efficiently irradiated onto the irradiated object.

  In addition, according to the present invention, the display device includes the illumination device according to the present invention that can irradiate the display panel with light whose intensity is uniform in the plane direction, so that there is no occurrence of uneven brightness. High-quality images can be displayed on the display panel.

1 is an exploded view showing a liquid crystal display device 100 according to an embodiment of the present invention. It is a figure which shows a mode when the diffusing plate 3 and the backlight unit 1 are planarly viewed from the liquid crystal panel 2 side. FIG. 3 is a diagram illustrating a state where the printed circuit board 12 is fixed to the bottom 131 of the frame member 13. FIG. 2 is an exploded view showing a printed circuit board 12 and a bottom 131 of a frame member 13. 2 is a plan view of a printed circuit board 12. FIG. It is a figure which shows the positional relationship of the LED chip 111a supported by the base 111b, and the lens 112. FIG. It is a figure which shows the base 111b and LED chip 111a. It is a figure which shows the LED chip 111a and the base 111b which are mounted in the printed circuit board 12. It is a figure which shows typically the optical path of the light radiate | emitted from LED chip 111a. It is a figure which expands and shows a part when the light-emitting device 11 is planarly viewed from the liquid crystal panel 2 side. It is sectional drawing of the liquid crystal display device 100 when it cut | disconnects by the line AA shown in FIG. 2 and FIG. 4 is a cross-sectional view showing a configuration of a reflecting member 118. FIG. It is sectional drawing which shows the structure of 118 A of reflecting members which are the other examples of a reflecting member.

  Below, the liquid crystal display device 100 provided with the backlight unit 1 which is embodiment of this invention is demonstrated. FIG. 1 is an exploded view showing a liquid crystal display device 100 according to an embodiment of the present invention. The liquid crystal display device 100 includes a backlight unit 1, a liquid crystal panel 2, and a diffusion plate 3.

  The liquid crystal panel 2 includes two substrates and is configured in a rectangular flat plate shape. The liquid crystal panel 2 is supported by the side wall portion 132 of the frame member 13 so that the bottom surface 131a of the bottom portion 131 of the frame member 13 which is a casing included in the backlight unit 1 and the main surface of the liquid crystal panel 2 are substantially parallel. The The liquid crystal panel 2 includes a switching element such as a TFT (thin film transistor), and liquid crystal is injected into the gap between the two substrates. The two substrates are provided with a driver (source driver) for controlling driving of pixels, various elements, and wiring. The liquid crystal panel 2 configured as described above displays an image on the display screen 2a which is one of the main surfaces when irradiated with light from the backlight unit 1.

  The diffusion plate 3 is a rectangular flat plate member. The diffusion plate 3 is supported between the liquid crystal panel 2 and the backlight unit 1 by the side wall portion 132 of the frame member 13 so that the main surface of the liquid crystal panel 2 and the main surface of the diffusion plate 3 are parallel to each other. . The diffusing plate 3 prevents the luminance of the display screen 2a from being locally biased by diffusing the light emitted from the backlight unit 1 in the surface direction of the diffusing plate 3.

  As another embodiment of the present invention, a prism sheet may be disposed between the liquid crystal panel 2 and the diffusion plate 3. The prism sheet converts the traveling direction of the light that has reached through the diffusion plate 3 into the thickness direction of the liquid crystal panel 2 to improve the luminance of the display screen 2a.

  FIG. 2 shows a state when the diffusing plate 3 and the backlight unit 1 are viewed in plan from the liquid crystal panel 2 side. The backlight unit 1 is a direct illumination device that irradiates light from the back side, which is the main surface opposite to the display screen 2a, with respect to the liquid crystal panel 2. The backlight unit 1 includes a plurality of light emitting devices 11 each having a light emitting unit 111 and a reflecting member 118, a plurality of printed circuit boards 12, and a frame member 13.

  In FIG. 2, in the backlight unit 1, a plurality of light emitting devices 11 are arranged in a matrix, and seven light emitting devices 11 are arranged in the row direction and 12 in the column direction. However, the number of the light emitting devices 11 is not limited to this. In FIG. 2, seven light emitting devices 11 are arranged in the row direction and twelve in the column direction in the matrix arrangement, but in the present embodiment, 14 light emitting devices 11 are arranged in the row direction and in the column direction. 24 are arranged.

  The frame member 13 includes a flat bottom 131 that faces the liquid crystal panel 2 with a predetermined interval, and four side walls 132 that are connected to the bottom 131 and rise from the bottom 131. The bottom 131 has a rectangular shape when viewed in the thickness direction, and is slightly larger than the liquid crystal panel 2. The side wall part 132 rises toward the liquid crystal panel 2 from two end parts that form a rectangular short side and two end parts that form a long side when viewed in the thickness direction in the bottom part 131. It is formed. The thickness of the frame member 13 is, for example, 0.8 mm to 1.0 mm.

  FIG. 3 shows a state where the printed circuit board 12 is fixed to the bottom 131 of the frame member 13. FIG. 4 shows the printed circuit board 12 and the bottom 131 of the frame member 13 in an exploded manner. Further, FIG. 5 shows a plan view of the printed circuit board 12.

  The printed circuit board 12 is fixed to the bottom surface 131 a of the bottom 131 of the frame member 13. A plurality of light emitting units 111 are provided on the mounting surface 12 a of the printed circuit board 12. The printed circuit board 12 is a substantially rectangular plate-shaped member having a width of, for example, 10 mm and a thickness of, for example, 0.8 mm. The plurality of printed circuit boards 12 are provided in parallel in the width direction, for example, 30 mm apart.

  The printed circuit board 12 is, for example, a substrate made of glass epoxy having a conductive pattern printed on both sides. The printed circuit board 12 extends to the side wall 132 of the frame member 13, and a connector 132 a provided on the side wall 132 for supplying power to the printed circuit board 12 is connected to the conductive pattern of the printed circuit board 12. . Each light emitting unit 111 on the printed circuit board 12 is supplied with power through the connector 132a and the conductive pattern.

  The printed circuit board 12 is formed with positioning round holes 12b, positioning long holes 12c, and a plurality of fixing long holes 12d. Positioning projections 131b and 131c formed on the bottom surface 131a of the bottom 131 of the frame member 13 are inserted into the positioning round hole 12b and the positioning long hole 12c, respectively. A fixing pin 12e is inserted into the fixing long hole 12d, and the fixing pin 12e is fixed in a fixing hole 131d formed in the bottom 131 of the frame member 13 through a pin receiving member 12f. .

As shown in FIG. 2, the plurality of light emitting devices 11 are arranged in a matrix. Each light emitting device 11 is formed in a square when viewed in a direction perpendicular to the bottom surface 131a of the bottom 131 of the frame member 13 (X direction), and the length of one side of the square is, for example, 55 mm. Each light-emitting device 11 is designed so that the amount of light in the area facing the square in the liquid crystal panel 2 is, for example, 6000 cd / m ² .

  The light emitting device 11 is provided around the light emitting unit 111 that emits light toward the liquid crystal panel 2 that is an object to be irradiated, and reflects the light emitted from the light emitting unit 111 toward the liquid crystal panel 2. And a reflecting member 118. The reflecting member 118 includes a sub-reflecting portion 1182 that is a first reflecting portion that surrounds the light-emitting portion 111 and extends at a predetermined angle with respect to the optical axis S of the light-emitting portion 111. That's fine. In the present embodiment, the reflecting member 118 extends in a direction perpendicular to the X direction, and a main reflecting portion 1181 serving as a second reflecting portion whose outer shape when viewed in the X direction is a flat plate having a polygonal shape, And a sub-reflecting portion 1182 that is a flat plate having a main surface that extends to the main surface of the main reflecting portion 1181 in an inclined manner. Details of the reflecting member 118 will be described later.

  The light emitting unit 111 includes a light emitting diode (LED) chip 111a, a base 111b that supports the LED chip 111a, and a lens 112. FIG. 6 is a diagram showing a positional relationship between the LED chip 111a supported by the base 111b and the lens 112. As shown in FIG. The base 111b is a member for supporting the LED chip 111a. The base 111b is formed in a square when the support surface for supporting the LED chip 111a is viewed in plan in the X direction, and the length L1 of one side of the square is, for example, 3 mm. Moreover, the X direction length of the base 111b is 1 mm, for example.

  FIG. 7 is a diagram showing the base 111b and the LED chip 111a, FIG. 7 (a) is a plan view, FIG. 7 (b) is a front view, and FIG. 7 (c) is a bottom view. . The base 111b includes a base main body 111g made of ceramic, resin, and the like, and two electrodes 111c provided on the base main body 111g. The LED chip 111a is a base main body that serves as a support surface of the base 111b. It is fixed to the central portion of the upper surface of 111g with an adhesive member 111f. The two electrodes 111c are spaced apart from each other, and are respectively provided over the top surface, the side surface, and the bottom surface of the base body 111g.

  The two electrodes 111c and two terminals (not shown) of the LED chip 111a are connected by two bonding wires 111d, respectively. The LED chip 111a and the bonding wire 111d are sealed with a transparent resin 111e such as silicon resin.

  FIG. 8 shows the LED chip 111a and the base 111b mounted on the printed circuit board 12. The LED chip 111a is mounted on the printed circuit board 12 via the base 111b, and emits light in a direction from the printed circuit board 12 to the liquid crystal panel 2. The direction of the optical axis S of the LED chip 111a is the X direction. The LED chip 111a is located at the center of the base 111b when the light emitting device 11 is viewed in plan in the X direction. In the plurality of light emitting devices 11, the light emission control by the LED chips 111 a can be controlled independently of each other. Thereby, the backlight unit 1 can perform partial dimming control (local dimming).

  When mounting the LED chip 111a and the base 111b on the printed circuit board 12, first, solder is respectively applied to the two connection terminal portions 121 of the conductive pattern provided in the printed circuit board 12, and the base body is attached to the solder. The base 111b and the LED chip 111a fixed to the base 111b are placed on the printed circuit board 12 by, for example, an automatic machine (not shown) so that the two electrodes 111c provided on the bottom surface of 111g match each other. The printed circuit board 12 on which the base 111b and the LED chip 111a fixed to the base 111b are placed is sent to a reflow bath that irradiates infrared rays, and the solder is heated to about 260 ° C., and the base 111b, the printed circuit board 12, Is soldered.

  The lens 112 shown in FIG. 6 is provided in contact with the base 111b so as to cover the LED chip 111a and the base 111b that supports the LED chip 111a, and the light emitted from the LED chip 111a is transmitted to the LED chip 111a. Reflected or refracted in a plurality of directions intersecting the optical axis S. The lens 112 is a transparent lens, and is made of, for example, silicon resin or acrylic resin.

  In the lens 112, an upper surface 112a that is a surface facing the liquid crystal panel 2 is formed to be curved with a depression at the center. Further, the side surface 112b is formed in a cylindrical side surface shape having the direction of the optical axis S of the LED chip 111a as the axial direction.

  The lens 112 is formed rotationally symmetrical around the optical axis S. In the lens 112, a diameter L2 of a cross section orthogonal to the optical axis S is, for example, 10 mm. The lens 112 extends outward with respect to the base 111b. That is, the lens 112 is larger than the base 111b in the direction perpendicular to the optical axis S of the LED chip 111a (the diameter L2 of the lens 112 is larger than the length L1 of one side of the support surface of the base 111b). As described above, the lens 112 is provided so as to extend outward with respect to the base 111b, so that the light emitted from the LED chip 111a can be diffused by the lens 112 over a wide range. The height H1 of the lens 112 is 1.5 mm, for example, and is smaller than the diameter L2. That is, the maximum length of the lens 112 in the direction perpendicular to the optical axis S of the LED chip 111a is larger than the height H1.

  As described above, the diameter L2 is made larger than the height H1 in order to reduce the thickness of the backlight unit 1 and to uniformly irradiate the liquid crystal panel 2 with light. In order to reduce the thickness of the backlight unit 1, it is necessary to reduce the height H1 of the lens 112, that is, to make the lens 112 as thin as possible. However, if the lens 112 is made thinner, uneven illuminance is likely to occur on the back surface of the liquid crystal panel 2, and as a result, uneven brightness is likely to occur on the display screen 2 a of the liquid crystal panel 2. In particular, when the distance between the adjacent LED chips 111a is long, the portion of the back surface of the liquid crystal panel 2 between the adjacent LED chips 111a is far away from the two LED chips 111a, and the amount of irradiation light decreases. Therefore, illuminance unevenness (luminance unevenness) easily occurs between the portion and the portion facing the LED chip 111a. In order to irradiate the light emitted from the LED chip 111a to a region far from the LED chip 111a via the lens 112, it is necessary to increase the diameter L2 of the lens 112 to some extent. In this embodiment, the lens 112 By making the diameter L2 of the light source larger than the height H1, the backlight unit 1 can be made thinner and the liquid crystal panel 2 can be uniformly irradiated with light.

  If the diameter L2 of the lens 112 is made smaller than the height H1 of the lens 112, it becomes difficult to make the backlight unit 1 thin and uniform, and the lens 112 is fitted to the LED chip 111a. In insert molding to form, the subject that a balance tends to worsen arises. Further, when soldering the light emitting unit 111 composed of the LED chip 111a and the base 111b and the insert-molded lens 112 to the printed circuit board 12, the balance is easily lost, and there is a problem in assembly.

  An upper surface 112a of the lens 112 faces the LED chip 111a and is parallel to the main surface of the diffusion plate 3, a first curved portion 1122 surrounding the central portion 1121, and a second surrounding the first curved portion. A curved portion 1123. On the surface of the lens 112, the central portion 1121, the second curved portion 1123, and the side surface 112 b of the upper surface 112 a become a transmission region that transmits the light emitted from the LED chip 111 a and reaching the inside of the lens 112. Further, the first curved portion 1122 of the upper surface 112a becomes a reflection region that reflects the light emitted from the LED chip 111a and reaching through the inside of the lens 112 toward the side surface 112b.

  The central portion 1121 of the upper surface 112a is formed so that the center of the central portion 1121 (that is, the optical axis of the lens 112) is located on the optical axis S of the LED chip 111a at the center of the upper surface 112a. The central portion 1121 of the upper surface 112a is parallel to the light emitting surface of the LED chip 111a and is formed in a circular shape, and the circular diameter L3 is, for example, 1 mm. As another embodiment of the present invention, the shape of the central portion 1121 is a side shape of a virtual cone that has the circular bottom surface and protrudes toward the LED chip 111a instead of the circular shape. It may be.

  The central portion 1121 is formed for irradiating light to a region of the diffusing plate 3 that faces the central portion 1121. However, since the central portion 1121 is a portion facing the LED chip 111a, most of the light emitted from the LED chip 111a reaches the central portion 1121, and when most of the light is transmitted as it is, it faces the central portion 1121. The illuminance of the area to be markedly increased. Therefore, it is preferable that the shape of the central portion 1121 is the side shape of the cone. In the case of the conical side surface shape, most of the light is reflected by the central portion 1121 and less light is transmitted through the central portion 1121, so that the illuminance of the region facing the central portion 1121 can be suppressed.

  The first curved portion 1122 of the upper surface 112a is an annular curved surface that surrounds the outer peripheral edge portion of the central portion 1121 and continues to the outer peripheral edge portion, and this curved surface is outward about the optical axis S of the LED chip 111a. It extends to one side in the optical axis S direction (toward the liquid crystal panel 2) as it goes to and is curved to be convex inward and one in the optical axis S direction. Here, the outer peripheral edge portion is a portion that is the outermost portion around the optical axis S when viewed in plan in the direction of the optical axis S, and is a portion that makes one round around the optical axis S. In order to make the first curved portion 1122 a reflective region, the shape of the curved surface is designed so that the light emitted from the LED chip 111a is totally reflected.

  More specifically, of the light emitted from the LED chip 111a, the light that has reached the first curved portion 1122 is totally reflected by the first curved portion 1122, and then transmitted through the side surface 112b of the lens. Heading toward the main reflecting portion 1181. The light that reaches the main reflecting portion 1181 is diffused by the main reflecting portion 1181, and a part of the diffused light is irradiated to a region facing the main reflecting portion 1181 in the diffusion plate 3. Further, another part of the diffused light travels toward the sub-reflecting part 1182 of the reflecting member 118 and is diffused by the sub-reflecting part 1182, and the diffused light is irradiated to a region facing the sub-reflecting part 1182 in the diffusing plate 3. The In this way, it is possible to increase the amount of light applied to the region not facing the LED chip 111a.

  The first curved portion 1122 is formed such that the incident angle of the light emitted from the LED chip 111a is equal to or greater than the critical angle φ in order to totally reflect the light emitted from the LED chip 111a. For example, when the material of the lens 112 is an acrylic resin, the refractive index of the acrylic resin is “1.49” and the refractive index of air is “1”, and thus sin φ = 1.1 / 49. From this equation, the critical angle φ is 42.1 °, and the first curved portion 1122 is formed in a shape with an incident angle of 42.1 ° or more. For example, when the lens 112 is made of silicon resin, the refractive index of silicon resin is “1.43” and the refractive index of air is “1”, so sin φ = 1 / 1.43. . From this equation, the critical angle φ is 44.4 °, and the first curved portion 1122 is formed in a shape with an incident angle of 44.4 ° or more.

  The second curved portion 1123 of the upper surface 112a is connected to the outer peripheral edge of the first curved portion 1122, and the other in the optical axis S direction (away from the liquid crystal panel 2) as it goes outward with the optical axis S of the LED chip 111a as the center. Is an annular curved surface that is curved so as to protrude outward and in one direction in the optical axis S direction.

  Of the light emitted from the LED chip 111a, the light that has reached the second curved portion 1123 is refracted in the direction toward the light emitting portion 111 when passing through the second curved portion 1123, and the diffusing plate 3 and the reflecting member. Head to 118. The light reaching the reflection member 118 is diffused and travels toward the diffusion plate 3. Thus, the light traveling toward the diffusion plate 3 by the second curved portion 1123 is mainly irradiated to a region different from the region irradiated with light by the central portion 1121 and the first curved portion 1122 in the diffusion plate 3. The amount of light is complemented. Since the second curved portion 1123 needs to transmit light, the incident angle is less than 42.1 ° so as not to totally reflect the light emitted from the LED chip 111a.

  As described above, the lens 112 is formed with the first curved portion 1122 that totally reflects the light emitted from the LED chip 111a toward the side surface 112b of the lens 112 at the outer peripheral edge portion of the central portion 1121. A second curved portion 1123 that refracts the light emitted from the LED chip 111a is formed at the outer peripheral edge of the curved portion 1122. The LED chip 111a generally has high directivity, the amount of light near the optical axis S is extremely large, and the amount of light decreases as the light emission angle with respect to the optical axis S increases. Therefore, in order to increase the amount of light emitted to the region relatively far from the optical axis S of the LED chip 111a (that is, the optical axis of the lens 112), light having a large emission angle with respect to the optical axis S is directed to this region. Instead, it is necessary to direct light having a small emission angle to this region.

  In the present embodiment, as described above, the first curved portion 1122 that totally reflects the light toward the region is formed around the central portion 1121 through which the optical axis S passes. The amount of light irradiated to the can be increased. On the other hand, if the second curved portion 1123 is formed adjacent to the periphery of the central portion 1121, and the first curved portion 1122 is formed adjacent to the second curved portion 1123, The emission angle of the light traveling toward the first curved portion 1122 with respect to the optical axis S increases, and as a result, the amount of light that is totally reflected by the first curved portion 1122 and applied to the region is reduced.

  FIG. 9 is a diagram schematically showing an optical path of light emitted from the LED chip 111a. The light emitted from the LED chip 111 a enters the lens 112, and is reflected and refracted by the lens 112. Specifically, of the light incident on the lens 112, the light reaching the central portion 1121 is emitted toward the liquid crystal panel 2 in the direction of the arrow A1, and the light reaching the first curved portion 1122 is all The light that is reflected and emitted from the side surface 112b in the direction of the arrow A2 and reaches the second curved portion 1123 is refracted and emitted toward the liquid crystal panel 2 in the direction of the arrow A3 and the like.

  In the present embodiment, the LED chip 111a and the lens 112 are such that the center of the lens 112 (that is, the optical axis of the lens 112) is positioned on the optical axis S of the LED chip 111a, and the lens 112 is in contact with the LED chip 111a. In addition, it is formed in advance with high accuracy. As described above, the LED chip 111a and the lens 112 can be formed by previously aligning them by insert molding or fitting the LED chip 111a supported by the base 111b to the lens 112 molded into a predetermined shape. The method of combining can be mentioned. In the present embodiment, the LED chip 111a and the lens 112 are formed by being previously aligned by insert molding.

  When insert molding is performed, an upper surface mold and a lower surface mold are roughly used. Molding is performed by injecting a resin, which is a raw material of the lens 112, from a resin inlet into a space formed when the upper surface mold and the lower surface mold are combined. In addition, in a state where the LED chip 111a supported by the base 111b is held in the space formed when the upper surface mold and the lower surface mold are combined, the resin as the raw material of the lens 112 is injected from the resin injection port. You may make it shape | mold by doing. Thus, by forming the LED chip 111a and the lens 112 by insert molding, it is possible to align the lens 112 with high accuracy so that the lens 112 contacts the LED chip 111a. Thus, the backlight unit 1 can accurately reflect and refract the light emitted from the LED chip 111a by the lens 112 in contact with the LED chip 111a. Therefore, the diffusion plate shown in FIG. Even in the thinned liquid crystal display device 100 with a small distance H3 from 3 to the printed circuit board 12 (H3 is 6 mm, for example), the liquid crystal panel 2 can be irradiated with light whose intensity is uniform in the surface direction.

  Next, the reflecting member 118 will be described. FIG. 10 is an enlarged view showing a part of the light emitting device 11 in plan view from the liquid crystal panel 2 side. FIG. 11 is a cross-sectional view of the liquid crystal display device 100 taken along line AA shown in FIGS. 2 and 10. FIG. 12 is a cross-sectional view showing the configuration of the reflecting member 118. 12A shows a cross-sectional view of the reflecting member 118 when cut along the line BB shown in FIG. 2, and FIG. 12B shows the reflection when cut along the line CC shown in FIG. A cross-sectional view of the member 118 is shown.

  A portion (a part of a sub-reflecting portion 1182 described later) corresponding to the edge portion of the bottom portion 131 of the reflecting member 118 provided around each light emitting portion 111 arranged at the edge portion of the bottom portion 131 in the frame member 13. As shown in FIG. 12, the frame member 13 is supported by the side wall portion 132. The side wall 132 is formed such that an end opposite to the end connected to the bottom 131 is bent outward (bent), and a part of the reflecting member 118 is formed in the bent portion. Is placed, the reflecting member 118 is supported on the side wall 132.

  In addition, in a state where a part of the reflection member 118 is placed on the bent portion of the side wall part 132, the edge of the diffusion plate 3 is placed so as to overlap the part of the reflection member 118. The diffusion plate 3 is supported by the side wall portion 132. In FIG. 12, a gap is formed between the bottom 131 of the frame member 13 and the reflecting member 118, and this gap corresponds to the thickness of the printed circuit board 12.

  The reflecting member 118 is a member having a high reflectance, ideally 100%, with respect to the light emitted from the LED chip 111a. In the present embodiment, the reflecting member 118 is white and has a total reflectance of 95% to 98% with respect to the light emitted from the LED chip 111a. The reflectance of the material constituting the reflecting member 118 can be measured according to JIS K 7375.

  The reflecting member 118 is made of high-brightness PET (Polyethylene Terephthalate), aluminum, or the like. High-brightness PET is foamable PET containing a fluorescent agent, and examples thereof include E60V (trade name) manufactured by Toray Industries, Inc. The reflection member 118 has a polygonal shape, for example, a substantially square shape, when viewed in plan in the X direction. When the length of one side of the square shape is 55 mm, the reflection member 118 is located between the centers of adjacent reflection members 118. The interval is, for example, 55 mm to 58 mm.

  The main reflecting portion 1181 of the reflecting member 118 is a flat plate member having a thickness of 0.1 mm to 0.5 mm, and the outer shape when viewed in a plane in the X direction is a polygonal shape, for example, a square shape. The main reflecting portion 1181 is provided on the printed circuit board 12 so as to extend in a direction perpendicular to the optical axis S of the LED chip 111a, and each square side when viewed in plan in the X direction has a plurality of LED chips. It is formed so as to be parallel to the arrangement direction of 111a (the row direction or the column direction in the matrix-like arrangement).

  The main reflecting portion 1181 is provided with a circular opening at the center when viewed in plan in the X direction. The diameter of the circular opening is 10 mm to 13 mm, which is about the same as the diameter L2 of the lens 112 covering the LED chip 111a, and the light emitting unit 111 including the lens 112 is mounted on the printed circuit board 12. After that, when the reflecting member 118 is installed on the printed circuit board 12, the light emitting unit 111 is inserted into the opening.

  The sub-reflecting portion 1182 of the reflecting member 118 is a rectangular flat plate member having a thickness of 0.1 mm to 0.5 mm, and is provided continuously to the four side portions of the main reflecting portion 1181. Here, the side portion of the main reflection portion 1181 is a portion that becomes an outer peripheral edge portion of the square main reflection portion 1181 when the main reflection portion 1181 is viewed in plan in the X direction. The outer peripheral edge of the square main reflecting portion 1181 is a portion that goes around the optical axis S when viewed in plan in the optical axis S direction (X direction). A portion having a predetermined width that is the outermost side in each direction perpendicular to the axis S. The predetermined width is, for example, a width of 1% to 10% of the length of one side of the square main reflecting portion 1181.

  The main surface of each sub-reflective portion 1182 is inclined so as to move away from the printed circuit board 12 in the optical axis S direction and toward the diffuser plate 3 as it moves away from the main reflective portion 1181 in the direction perpendicular to the optical axis S direction of the LED chip 111a. And formed to extend. Since each sub-reflecting part 1182 is provided on a different side part of the main reflecting part 1181, each sub-reflecting part 1182 is inclined in a different direction. The inclination angle θ1 and the inclination angle θ2 of each sub-reflecting portion 1182 with respect to the optical axis S can be appropriately set within a range of 0 ° or more and less than 90 °.

  As shown in FIGS. 11 and 12, in the adjacent light emitting devices 11, the adjacent sub-reflecting portions 1182 are in contact with each other and form an inverted V shape. The inverted V shape indicates that the cross section when cut in parallel to the optical axis S is perpendicular to the side portion of the main reflecting portion 1181 to which the sub-reflecting portion 1182 is connected.

  The height H2 of the reflecting member 118 is, for example, 1 mm to 5 mm, and is 1.5 mm in this embodiment. Here, the height H2 is the distance in the X direction between the portion of the sub-reflecting portion 1182 that is farthest from the surface of the main reflecting portion 1181 in the X direction and the surface of the main reflecting portion 1181.

  The reflection members 118 configured as described above and provided in each of the plurality of light emitting devices 11 are preferably formed integrally with each other. As a method of integrally forming the plurality of reflecting members 118, when the reflecting member 118 is made of foamable PET, an extrusion molding process can be cited, and when the reflecting member 118 is made of aluminum, A press working can be mentioned. As described above, by integrally forming the reflecting members 118 respectively provided in the plurality of light emitting devices 11, it is possible to improve the accuracy of the arrangement positions of the respective light emitting units 111 with respect to the respective reflecting members 118. As a result, the reflecting members The light can be reflected by 118 so that the luminance of the irradiated object becomes more uniform in the surface direction. Further, by integrally forming the reflection member 118, the number of operations for attaching the reflection member 118 can be reduced during the assembly operation of the backlight unit 1, so that the efficiency of the assembly operation can be improved.

  When the plurality of reflecting members 118 are integrally formed, the sub-reflecting portions 1182 that form the inverted V-shape are continuously provided. In the present embodiment, the reflecting members 118 are also connected to each other in the portion other than the sub-reflecting portion 1182.

  In the present embodiment, in the adjacent light emitting devices 11 (adjacent reflecting members 118), the sub-reflecting portions 1182 forming the inverse V-shape (region portions of the sub-reflecting portion 1182 facing each other) are In the frame member 13, the sub-reflective portion 1182 (center part separation) farther from the center part of the bottom part 131 than the sub-reflective part 1182 (center part side-side sub-reflective part) closer to the center part of the bottom part 131. The collateral sub-reflecting unit) is set to have a large projected area when projected in the direction of the optical axis S (projected area when projected onto the irradiated object).

  Here, the central portion of the bottom 131 in the frame member 13 is a region portion of the bottom 131 corresponding to the light emitting device 11 (the light emitting device 11 that is shaded in FIG. 10) located near the center of the bottom 131. . The light emitting devices 11 positioned in the vicinity of the center of the bottom portion 131 are 14 in the row direction (direction parallel to the short side direction of the bottom portion 131) in the matrix arrangement, and the column direction (direction parallel to the long side direction of the bottom portion 131). ) Of the light emitting device 11 arranged in 24) is the seventh from the one edge in the short side direction of the bottom 131 and the twelfth from the one edge in the long side of the bottom 131 The light emitting device 11 and the seventh light emitting device 11 from one edge in the short side direction of the bottom 131 and the twelfth light emitting device 11 from the other edge in the long side of the bottom 131 and the bottom 131 The seventh light emitting device 11 from the other edge in the short side direction and the twelfth light emitting device 11 from the one edge in the long side direction of the bottom 131 and the other edge in the short side of the bottom 131 12 pieces from the other edge of the long side direction of the bottom 131. The light emitting device 11 of a total of a four light emitting devices 11.

  Further, for example, when 14 light emitting devices 11 in the row direction and 25 light emitting devices 11 are arranged in the column direction in the matrix-like arrangement, it is the seventh from both edge portions in the short side direction of the bottom 131. In addition, a total of two light emitting devices 11, which are thirteenth from both edge portions in the long side direction of the bottom portion 131, are the light emitting devices 11 positioned near the center of the bottom portion 131. For example, in the case where 15 light emitting devices 11 are arranged in the row direction and 25 in the column direction in the matrix-like arrangement, the number of the light emitting devices 11 is the eighth from both edge portions in the short side direction of the bottom 131. The thirteenth light emitting device 11 from both edge portions of the bottom portion 131 in the long side direction is the light emitting device 11 located in the vicinity of the center of the bottom portion 131.

  In the present embodiment, in the adjacent light emitting devices 11, the projected areas when the sub-reflecting portions 1182 forming the inverted V shape are projected in the optical axis S direction are the optical axes S of the sub-reflecting portions 1182. It can be adjusted by the magnitude of the inclination angle θ1 and the inclination angle θ2.

  Specifically, in the sub-reflective portions 1182 that form the inverted V shape between the adjacent light emitting devices 11, the sub-reflective portion 1182 that is closer to the central portion of the bottom portion 131 (the central portion adjacent side sub-portion). The tilt angle θ1 of the sub-reflecting portion 1182 (center-parting side sub-reflecting portion) farther from the central portion of the bottom 131 than the tilt angle θ2 of the reflecting portion) with respect to the optical axis S is relative to the optical axis S. Is set to be large.

  In this case, for example, the height H2 of all the sub-reflective portions 1182 is set to the same value of 3 mm, and the same value (within the range of the tilt angle θ2 of the center-side proximity side sub-reflective portion of 10 ° to 20 °) For example, the inclination angle θ1 of the central portion separation side sub-reflection portion is set to the same value (for example, 45 °) within the range of 45 ° to 60 °. In addition, the inclination angle with respect to the optical axis S of the sub-reflecting portion 1182 of the reflecting member 118 provided in the light emitting device 11 located in the vicinity of the center of the bottom portion 131 is set to the same value as the inclination angle θ2 of the central-side near-side sub-reflecting portion. Is done.

  In the backlight unit 1 of the present embodiment, the projection area when the sub-reflecting portions 1182 forming the inverted V-shape are projected in the direction of the optical axis S in the adjacent light emitting devices 11 is close to the central portion. Since the center-part-separated side sub-reflective part is larger than the side sub-reflective part, the amount of light reflected by the reflecting member 118 corresponding to each light-emitting part 111 is the reflection corresponding to the center-side proximity side sub-reflective part. The number of reflecting members 118 corresponding to the center-part-separating side sub-reflecting portion is larger than that of the member 118.

  Therefore, the amount of light reflected by each reflecting member 118 corresponding to each light emitting unit 111 and reaching the liquid crystal panel 2 via the diffusion plate 3 is smaller than one light emitting unit 111 in the surface direction of the liquid crystal panel 2. It can suppress that an edge part with few numbers of the adjacent light emission parts 111 becomes fewer than a center part. That is, the amount of light that is reflected by each reflecting member 118 corresponding to each light emitting unit 111 and reaches the liquid crystal panel 2 can be made uniform in the surface direction of the liquid crystal panel 2, and as a result, the surface of the liquid crystal panel 2. The luminance in the direction can be made uniform.

  FIG. 13 is a cross-sectional view showing a configuration of a reflecting member 118A which is another example of the reflecting member. The inclination angle θ1 and the inclination angle θ2 with respect to the optical axis S of the sub-reflecting part 1182A in the reflecting member 118A are set to increase stepwise from the center part of the bottom part 131 to the outer peripheral edge part in the frame member 13. Yes. In other words, the projected area of the sub-reflecting portion 1182A in the reflecting member 118A is set to increase stepwise from the center portion of the bottom portion 131 toward the outer peripheral edge portion. In the present embodiment, in the plurality of light emitting devices 11 arranged in a matrix on the bottom portion 131 of the frame member 13, the light emitting portions 111 are arranged at equal intervals on the bottom portion 131 via the printed circuit board 12. Yes. Therefore, corresponding to the fact that the projected area of the sub-reflecting part 1182 in the reflecting member 118A is set as described above, the projected area of the main reflecting part 1181A in the reflecting member 118A when projected in the optical axis S direction. Is set to decrease stepwise from the center of the bottom 131 toward the outer peripheral edge.

  Specifically, in the sub-reflective portions 1182A that form the inverted V shape in the adjacent light emitting devices 11, the sub-reflective portions 1182A (the center of the frame member 13 that is closer to the central portion of the bottom 131). The inclination angle θ2 with respect to the optical axis S of the sub-proximity-side sub-reflection portion) is set to increase stepwise from the central portion of the bottom portion 131 toward the outer peripheral edge portion, and with respect to the central portion of the bottom portion 131 The inclination angle θ1 with respect to the optical axis S of the far-side sub-reflecting part 1182A (center-parting side sub-reflecting part) is also set to increase stepwise from the center part of the bottom part 131 toward the outer peripheral edge part. ing.

  In this case, the height H2 of all the sub-reflecting portions 1182A is set to the same value of 3 mm, and the optical axis of the sub-reflecting portion 1182A of the reflecting member 118A provided in the light emitting device 11 located near the center of the bottom portion 131 is set. The inclination angle with respect to S is set to a value within the range of 10 ° to 20 ° (for example, 10 °). As shown in FIG. 13A, in the long side direction of the bottom portion 131, the inclination angle θ2 with respect to the optical axis S of the central portion side sub-reflection portion is from the central portion of the bottom portion 131 toward the outer peripheral edge portion. In order, it is set so as to increase stepwise within a range of 10 ° to 20 °. At this time, the inclination angle θ2 of the center-side proximity-side sub-reflective portion corresponding to the reflecting member 118A provided in the light emitting device 11 adjacent to the light emitting device 11 located in the vicinity of the center of the bottom portion 131 is set to 10 °. The inclination angle θ2 of the central-side near-side sub-reflective portion corresponding to the reflective member 118A provided in the light emitting device 11 located at the outermost peripheral edge is set to 20 °.

  In the long side direction of the bottom portion 131, the inclination angle θ1 with respect to the optical axis S of the central portion separation side sub-reflective portion is in the range of 45 ° to 55 ° in order from the central portion of the bottom portion 131 toward the outer peripheral edge. It is set to increase in steps. At this time, the inclination angle θ1 of the center-parting-side sub-reflective part adjacent to the sub-reflective part 1182A of the reflecting member 118A provided in the light emitting device 11 located in the vicinity of the center of the bottom part 131 is set to 45 °. The inclination angle θ1 of the central portion separation side sub-reflective portion corresponding to the reflective member 118A provided in the light emitting device 11 located at the outermost peripheral edge is set to 55 °.

  Further, as shown in FIG. 13B, in the short side direction of the bottom portion 131, the inclination angle θ2 with respect to the optical axis S of the central portion side sub-reflection portion is from the central portion of the bottom portion 131 toward the outer peripheral edge portion. In order, it is set to increase stepwise within a range of 10 ° to 16 °. At this time, the inclination angle θ2 of the center-side proximity-side sub-reflective portion corresponding to the reflecting member 118A provided in the light emitting device 11 adjacent to the light emitting device 11 located in the vicinity of the center of the bottom portion 131 is set to 10 °. The inclination angle θ2 of the central proximity side sub-reflective portion corresponding to the reflective member 118A provided in the light emitting device 11 located at the outermost peripheral edge is set to 16 °.

  In the short side direction of the bottom portion 131, the inclination angle θ1 with respect to the optical axis S of the central portion separation side sub-reflecting portion is in the range of 45 ° to 51 ° in order from the central portion of the bottom portion 131 toward the outer peripheral edge. It is set to increase in steps. At this time, the inclination angle θ1 of the center-parting-side sub-reflective part adjacent to the sub-reflective part 1182A of the reflecting member 118A provided in the light emitting device 11 located in the vicinity of the center of the bottom part 131 is set to 45 °. The inclination angle θ1 of the central portion separation side sub-reflective portion corresponding to the reflective member 118A provided in the light emitting device 11 located at the outermost peripheral edge is set to 51 °.

  As described above, in the sub-reflecting portions 1182A that form the inverted V shape in the adjacent light-emitting devices 11, the inclination angle θ2 with respect to the optical axis S of the center-side proximity-side sub-reflecting portion and the center-part-separated side By setting the inclination angle θ1 of the sub-reflecting part with respect to the optical axis S so as to increase stepwise from the center part of the bottom part 131 toward the outer peripheral edge part, each reflecting member 118A corresponding to each light emitting part 111 The amount of light that is reflected and reaches the liquid crystal panel 2 via the diffusion plate 3 can be made more effective and uniform in the surface direction of the liquid crystal panel 2, and as a result, the luminance in the surface direction of the liquid crystal panel 2 can be increased. It can be made uniform.

DESCRIPTION OF SYMBOLS 1 Backlight unit 2 Liquid crystal panel 3 Diffusion plate 11 Light-emitting device 12 Printed circuit board 13 Frame member 100 Liquid crystal display device 111 Light-emitting part 118,118A Reflective member 1181,1181A Main reflection part 1182,1182A Sub-reflection part

Claims (5)

A housing having a bottom;
A plurality of light emitting portions for emitting light, arranged in alignment at the bottom;
A reflecting member that is provided around each light emitting unit and reflects light emitted from the light emitting unit toward an irradiated body, and extends at an angle with respect to the optical axis of the light emitting unit. A reflective member having a first reflective part surrounding the light emitting part,
In adjacent reflecting members, the region portions of the first reflecting portion facing each other are located closer to the center portion of the bottom portion than the region portion of the first reflecting portion disposed at a position closer to the center portion of the bottom portion. An illumination device, wherein a region of the first reflecting portion arranged at a far position is large in projected area when projected in the optical axis direction.   The projected area of the first reflecting portion of each reflecting member when projected in the direction of the optical axis increases stepwise from the center of the bottom toward the edge. The lighting device described.   In adjacent reflecting members, the region portions of the first reflecting portion facing each other are located closer to the center portion of the bottom portion than the region portion of the first reflecting portion disposed at a position closer to the center portion of the bottom portion. 3. The lighting device according to claim 1, wherein a region portion of the first reflecting portion disposed at a far position is set so that an inclination angle with respect to the optical axis is increased. The reflecting member further includes a second reflecting portion that extends in a direction perpendicular to the optical axis, and whose outer shape when viewed in the optical axis direction is a polygonal shape,
The lighting device according to any one of claims 1 to 3, wherein the first reflecting portion extends continuously from a side portion of the second reflecting portion. A display panel;
A display device comprising: the illumination device according to claim 1, which irradiates light to the display panel.

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