JP2009187904A - Light source unit, back light unit, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source unit which improves a utilization ratio of light emitted by a light source and makes it lighter in weight and more compact and provide a backlight unit and a display using the above. <P>SOLUTION: In the light source unit 10 in which the one surface serves as a light emitting surface 12 emitting light of an LED array 14 and the light is arranged to be emitted from an entire area of the light emitting surface, a diffusion reflecting plate 13a is arranged to face a rear surface side of the light emitting surface 12 with an air layer 17 in-between, and the light from the LED array 14 is not emitted directly from the light emitting surface 12 but is emitted from the light emitting surface 12 through a reflection by the diffusion reflection plate 13a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light source unit that diffuses light incident from a light source and emits uniform illumination light from an emission surface, a backlight unit that illuminates a liquid crystal panel or the like from the back side using the light source unit, and a display device.

  In recent years, liquid crystal display devices (LCDs) using liquid crystal panels have been used in notebook personal computers, personal computer displays, image display means for information terminal equipment, image display means for information appliances such as large-screen TVs, mobile phones and personal use. 2. Description of the Related Art It has been used in various fields as an image display means of a personal digital assistant (PDA: Personal Digital Assistance). In a display device represented by a liquid crystal display device, a type having a built-in light source necessary for recognizing provided information is remarkably widespread.

  In such a display device, the demand for thinning has been increasing year by year, but as a conventional display device that has been thinned, for example, as described in Patent Documents 1 to 5, the back surface of a liquid crystal panel is used. Some surface light source devices that include a light source on the side, convert light from the light source into surface light emission via a light guide, and irradiate a liquid crystal panel include a so-called backlight unit.

  These backlight units, for example, on the light guide disposed between the light source and the image display unit, the transmittance adjustment for adjusting the luminance distribution of the planar light emitted from the exit surface of the light guide Body unit, a diffusion film that diffuses light that has passed through the transmittance adjusting body unit, and a plurality of prism sheets that condense the diffused light so as to be directed in a specific direction (for example, a normal direction to the image display unit) Has been.

  In particular, these light guides are concave portions extending in a substantially cylindrical shape for disposing a rod-shaped light source composed of a cold cathode ray tube on the back surface facing the light emitting surface in a thick portion provided at the substantially central portion of the light emitting surface. Is forming. And in the back surface of a light guide, it forms by providing a back inclined part toward the thin edge part of both sides from the thick part which formed the recessed part. In the backlight unit described in Patent Document 1, a light quantity correction surface that promotes the emission of illumination light is formed by forming a groove with a triangular cross section on the light emitting surface of the light guide except for the portion directly above the light source. ing. A light diffusing plate or a prism sheet is disposed on the light exit surface side of the light guide, thereby reducing the overall thickness and reducing unnatural luminance unevenness of the emitted light.

Also, in the backlight units and liquid crystal display devices described in Patent Documents 2 to 5, a luminance adjusting unit is provided by providing a transmittance adjusting unit unit on the light exit surface side of the light guide, or providing a prism sheet, a diffusion sheet, or the like. The illumination light by the more uniform surface light emission is applied to the image display unit such as a liquid crystal panel.
Japanese Patent Laid-Open No. 9-304623 Japanese Patent Laid-Open No. 2005-23497 JP 2006-301518 A JP 2006-302687 A JP 2006-318754 A

By the way, in the above-mentioned backlight unit, the light guide plate is made of a transparent resin or the like, and allows light to pass therethrough with a high transmittance, but part of the light passing therethrough is absorbed by the light guide plate. In such a light guide plate, the light from the incident light source is repeatedly refracted and reflected to reach the exit surface, so that the optical path in the light guide is inevitably longer and the loss of light energy increases. There was a problem that.
Further, as long as the light guide plate is provided, the backlight unit has a certain amount of weight and thickness. Therefore, there is a problem that it is difficult to reduce the thickness and weight more than the current state.

  The present invention has been made in view of such a problem, and it is possible to improve the utilization efficiency of light emitted from a light source, and to use a light source unit that can be reduced in thickness and weight. An object of the present invention is to provide a backlight unit and a display device.

In order to solve the above problems, the present invention proposes the following means.
That is, in the light source unit according to the present invention, one surface forms an emission surface that emits light from the light source, and the light source unit is configured to emit the light from the entire emission surface. The light source is characterized in that the light from the light source is reflected by the diffuse reflector and emitted from the exit surface.

  In the light source unit having such a feature, the light emitted from the light source travels through the air layer and is scattered, but is reflected and diffused by the diffuse reflector and emitted from the emission surface to the outside. Even without providing a light guide plate, the optical path length to the exit surface can be increased and the light can be dispersed.

  The light source unit according to the present invention includes a light source array in which directional point light sources are arranged in series as the light source, and the light source array has an end in a width direction along a side of the emission surface. Further, the radiating light is arranged so as to be directed toward the diffusive reflecting plate, and the irradiation positions of the light radiated from the respective point light sources on the diffusing reflecting plate are dispersed.

  By adjusting the direction of each point light source that composes the light source array and dispersing the irradiation position of each point light source on the diffuse reflector, the light emitted from the exit surface can be made more uniform, and better It is possible to obtain a simple surface emission.

  Furthermore, in the light source unit according to the present invention, as the diffusive reflecting plate moves away from the light source array in a direction intersecting with the arrangement direction of the point light sources, the diffuser reflecting plate moves from the back side toward the emission surface side. Or an inclined surface inclined from the emission surface side toward the back surface side.

  By tilting the diffuse reflector in this way, the light emitted from the light source is reflected and scattered by the inclined surface of the diffuse reflector, and is emitted as light with a more uniform luminance.

  In the light source unit according to the present invention, the light source includes a light source array in which directional point light sources are arranged in series, and the light source array is in a direction orthogonal to the direction in which the point light sources are arranged. A plurality of the diffuse reflectors are arranged at intervals, and the diffuse reflectors are inclined surfaces that incline from the back side toward the exit surface side as they are separated from each of the light source arrays in a direction perpendicular to the direction in which the point light sources are arranged. It is characterized by being.

  According to the light source unit having such a feature, in addition to receiving contributions of diffusion and scattering by the diffuse reflection plate and the air layer without using the light guide plate, the light source array is evenly arranged in the entire width direction of the emission surface. Therefore, the luminance distribution of the emitted light can be made more uniform.

Furthermore, in the light source unit, it is preferable that the irradiation positions of the light emitted from the point light sources on the diffuse reflector are dispersed.
Thereby, similarly to the above, the light emitted from the emission surface can be made more uniform, and better surface emission can be obtained.

The light source is a directional point light source, and a plurality of light sources are arranged in a matrix on a surface parallel to the emission surface,
The light source unit according to claim 1, wherein the diffuse reflection plate forms a substantially quadrangular pyramid surface that individually surrounds each of the point light sources.

  According to the light source unit having such a feature, even if the light source is a point light source that is not in the form of an array, it can receive the contribution of diffusion and scattering by the diffuse reflector and the air layer without using the light guide plate. In addition, since the point light sources are evenly arranged in the entire width direction of the exit surface, the brightness distribution of the exit light can be made more uniform.

  In any one of the light source units described above, it is preferable that an unevenness is provided at a position at an irradiation position by each of the point light sources on the diffuse reflector.

  By providing the unevenness in this way, it is possible to improve the diffusibility of the diffusive reflecting plate, and to further reduce the luminance unevenness.

  Furthermore, in any one of the light source units described above, the point light source is preferably an LED.

  By using the LED, it is possible to realize high brightness and energy saving of the point light source.

  A backlight unit according to the present invention includes the light source unit according to any one of the above, and an optical sheet that is disposed to face the light emission surface of the light source unit and controls light emitted from the light emission surface. It is characterized by that.

  According to such a backlight unit, the light from the light source is emitted from the exit surface after being propagated through the optical air layer and reflected by the diffuse reflector disposed on the back side of the exit surface. In addition to being able to obtain a diffusing effect on the diffusive reflector, the contribution of the scattering effect in the air layer can be sufficiently received. Therefore, luminance unevenness can be reduced without using a conventional light guide plate, and the backlight unit itself can be made thinner and lighter.

  In the backlight unit according to the present invention, a light diffusion plate mixed with light diffusion particles is provided between the light source unit and the optical sheet.

  Thereby, before the light emitted from the light source unit is incident on the optical sheet, the light can be diffused in the light diffusing plate, so that the luminance unevenness of the light incident on the optical sheet from the light guide side is reduced. be able to.

  Furthermore, the backlight unit according to the present invention has a light transmissive substrate and a light reflection layer disposed on the incident surface side of the light transmissive substrate, and the light reflection layer transmits light. And a light control sheet including a light reflecting part for reflecting light, and in an area where the illuminance or luminance of light transmitted through the emission surface of the light source unit is high, the area of the opening of the light control sheet is It is characterized in that the area of the opening is set large in a region where the illuminance or luminance is low.

Thereby, the light emitted from the emission surface of the light source unit can be transmitted as substantially uniform illuminance or luminance by the light control sheet, and light with a good balance of illuminance or luminance can be emitted.
Instead of providing the light control sheet, the light from the light source unit may be scattered only by the diffusion plate, and substantially uniform light may be emitted toward the image display unit via the prism lens sheet or the lenticular lens sheet.

  A display device according to the present invention includes the backlight unit according to any one of the above, and an image display unit that is disposed on an emission surface side of the optical sheet and displays an image using light from the backlight unit as display light. It is characterized by consisting of.

  According to such a display device, the same effects as those of the light source unit and the backlight unit described above can be obtained.

  According to the light source unit, the backlight unit, and the display device according to the present invention, the light from the light source can be converted into a well-balanced surface light emission without using a light guide plate. It is possible to reduce the thickness and weight.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 and 2 show a display device according to a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of the display device, and FIG. 2 is a schematic front view showing an arrangement of light sources of a light source unit in the display device. FIG.
The light source unit and the backlight unit according to this embodiment will be described together with a display device using the light source unit and the backlight unit.

In FIG. 1, the display device 1 according to the present embodiment is a liquid crystal display device configured by providing a liquid crystal display element (screen display unit) 3 above a backlight unit 2 that emits light upward.
The liquid crystal display unit 3 includes, for example, a display element or panel 5 that controls a light transmission state according to an image signal for each of a plurality of pixel regions formed in a rectangular lattice shape, and light incident on the display element or panel 5. The polarizing plate 4a controls the polarization direction of the light and the polarizing plate 4b controls the polarization direction of the emitted light.
The liquid crystal display unit 3 is connected to a drive unit M and is driven by the drive unit M.

In such an arrangement, the upper direction in FIG. 1 may be simply referred to as the display screen side, the lower direction may simply be referred to as the back side or the light source side, and the left-right direction may be referred to as the width direction.
The display device 1 is a liquid crystal display device including the liquid crystal display unit 3, but may be a projection screen device, a plasma display, an EL display, or the like as long as it includes at least the backlight unit 2. The type of the image display unit that displays the image by projecting the light from the light unit 2 as display light or projection light is not limited.

  As shown in FIG. 1, the optical system in the backlight unit 2 is configured by sequentially stacking a light source unit 10, a light control sheet 20, a diffusion plate 6, and an optical sheet 7 from the back side toward the display screen side. Yes.

  The light source unit 10 includes a casing 11 having a box shape having a rectangular shape in a plan view, for example, and the light source unit 10 is provided with light from a light source provided therein and is opened on the display screen side surface of the casing 11. For example, it is configured to be able to emit light as surface emission from the emission surface 12 that is rectangular in plan view.

  A diffuse reflection plate 13 (13a, 13b) is laid on the inner bottom surface 11a and the inner side surface 11b in the housing 11 over the entire area. Among them, the diffuse reflection plate 13a on the inner bottom surface 11a side has a substantially plate shape having substantially the same dimensions as the plan view of the housing 11, and is disposed so as to face the emission surface 12 in parallel. Yes.

  In this embodiment, as shown in FIG. 2, the light source employs an LED array 14 in which LEDs 15 as point light sources are arranged in a plurality of lines. Note that the point light source is not limited to the LED 15 as long as it has a directivity having a light distribution peak, and may be a normal fluorescent lamp, a halogen lamp, a semiconductor laser, or the like.

  The LED array 14 extends in a direction perpendicular to the paper surface in FIG. 1, and a pair is arranged facing both ends in the width direction inside the housing 11. In the LED array 14 arranged in this way, the individual LEDs 15 constituting the LED array 14 are such that the traveling direction of the light of the light distribution peak of the light emitted radially is directed toward the diffuse reflector 13a. It is arranged to be inclined. Therefore, most of the light emitted from each LED 15 is directed toward the diffuse reflector 13a, and there is no light directed directly toward the emission surface 12. For example, when a highly directional light source such as a semiconductor laser is used, most of the emitted light can be directed only to the diffusing reflector 13a without directing it to the exit surface 12. .

Furthermore, in this LED array 14, the inclination angle of each LED is distributed so that the irradiation position of the light emitted from each LED 15 on the diffuse reflector 13a is dispersed so that the light emitted from the emission surface 12 is uniform. Is adjusted.
That is, for example, when the direction of the light distribution peak of the LEDs 15 arranged in a line is aligned, a part of the diffuse reflector 13a is excessively irradiated, which causes luminance unevenness. Therefore, by changing the light distribution peak of the light emitted from each LED 15, the position of the irradiation position on the diffuse reflection plate 13 is appropriately shifted, and the light emitted from the emission surface 12 is made uniform. For example, as shown in the schematic diagram of FIG. 2, the irradiation positions on the diffusive reflector are aligned with the irradiation positions of the LEDs facing in the width direction, and each LED is arranged in the irradiation position. It may be one that is continuously changed in the width direction toward the direction. Further, as long as the light from the emission surface 12 can be made uniform, it is not limited to such a dispersion method, and other methods may be used.

  In addition, the LED array 14 is disposed so that a pair is opposed to both ends in the width direction inside the housing 11, and one LED is disposed at one end in the width direction, or on the four sides of the housing 11 having a rectangular shape in plan view. Two sets may be arranged along.

  Further, in the light source unit 10, the periphery of the emission surface 12, which is the opening on the display screen side surface of the housing 11, extends in the width direction from the upper end of the inner surface 11 b of the housing 11 near the location where the LED array 14 is disposed. The light blocking unit 16 projects toward the center, thereby preventing the light diffusely reflected by the diffuse reflector 13 from going in the lateral direction away from the display screen side.

  The inside of the housing 11 of the light source unit 10 configured as described above is an air layer 17 except for the above-described components, and the light emitted from each LED 15 contributes to the scattering effect by the air layer 17. Then, the light is diffusely reflected by the diffusive reflecting plate 13 and scattered by the air layer 17 and then emitted from the emission surface 12.

  The light control sheet 20 is laminated along the emission surface 12 of the light source unit 10 described above. For example, the light control sheet 20 has a rectangular shape in plan view, and has a light-transmitting base 21 and a light-transmitting base 21. On the light incident surface side, a light reflecting layer 22 provided so as to face the light emitting surface 12 of the light source unit 10 is integrally provided. The light reflecting layer 22 is arranged in, for example, a concentric circle shape or a lattice shape, and attempts to reflect and scatter a part of light hitting the light reflecting layer 22.

As a material for forming the translucent substrate 21, various materials can be used depending on the application as long as the material has heat resistance, mechanical strength, and solvent resistance to withstand manufacturing in addition to transparency. . Specifically, for example, polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer Polyester resins such as coextruded films of polyethylene terephthalate / polyethylene naphthalate, polyamide resins such as nylon 6, nylon 66 and nylon 610, polyolefin resins such as polyethylene, polypropylene (PP) and polymethylpentene, polyvinyl chloride Vinyl resin such as polyacrylate, polymethacrylate, acrylic resin such as polymethyl methacrylate (PMMA), polyimide, polyamideimide, polyetherimide, etc. Engineering resins such as imide resins, polyarylate, polysulfone, polyethersulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyaramid, polyetherketone, polyethernitrile, polyetheretherketone, polyethersulfite, polycarbonate (PC), polystyrene, high impact polystyrene, acrylonitrile polystyrene copolymer, styrene resin such as ABS resin, cellulose film such as cellophane, cellulose triacetate, cellulose diacetate, and nitrocellulose.
And the translucent base material 21 is produced using, for example, a method of molding a heated raw material resin by extrusion molding or injection molding, a cast polymerization method of polymerizing and molding monomers, oligomers, etc. in a mold. be able to.

  Further, in the light control sheet 20, the light reflection layer 22 partially reflects light traveling from the light emission surface 12 of the light source unit 10 toward the translucent substrate 21 and is emitted from the light control sheet 20 to the display screen side. The luminance distribution or the illuminance distribution is controlled to be more uniform.

  The light reflection layer 22 includes, for example, light reflection portions 23 that reflect light incident on the light control sheet 20 and openings 24 that are provided between the adjacent light reflection portions 23 and 23 and transmit light alternately. A plurality are formed.

  The light reflecting portion 23 of the light reflecting layer 22 is formed of, for example, a white layer or a metal layer. As a material of the white layer, for example, a white pigment made of an inorganic material such as titanium dioxide, barium sulfate, and magnesium oxide is mixed in the transparent resin. The composite material made can be used. Moreover, as a metal layer, the vapor deposition layer which consists of a material with high reflectivity, such as silver and aluminum, and little light absorption can be used, for example.

  And although the light reflection layer 22 may be directly formed in the entrance plane side of the translucent base material 21 by printing or vapor deposition, you may form by transfer, for example. When the light reflecting layer 22 is formed by transfer, for example, a photosensitive resin film is attached to the light incident surface of the translucent substrate 21, and the surface opposite to the photosensitive film with respect to the translucent substrate 21. A lens portion is provided on the photosensitive resin film, and the photosensitive resin film is exposed to ultraviolet rays through the translucent substrate 21. Thereby, the adhesive force of the photosensitive resin film is reduced only in the focal point of the lens unit and the region in the vicinity thereof due to the condensing action of the lens unit.

  Then, the laminated body of the translucent base material 21 and the photosensitive resin film is pressed onto the release paper, and then the laminated body is peeled from the release paper. In this manner, the light reflecting layer 22 having the opening 24 in the focal point of the lens unit and the region in the vicinity thereof is obtained. Each opening 24 of the light reflecting layer 22 formed in this way is formed so that its central axis coincides with the optical axis of the corresponding lens part.

  Even when the printing method is used, for example, as described above, the light reflecting layer 22 can be easily formed by printing by providing a step on the light incident surface when the translucent substrate 21 is manufactured. . However, in order to make the central axis of each opening 24 of the light reflecting layer 22 coincide with the optical axis of the lens part, it is necessary to relatively align the lens part and the step formation position.

A diffusion plate 6 that diffuses light emitted from the light control sheet 20 is disposed on the light emission surface side of the light control sheet 20. The diffusing plate 6 is configured by dispersing and mixing fine particles (light diffusing particles) for scattering light into the transparent resin material, and is disposed through a slight space from the emission surface of the light control sheet 20. Yes. It is necessary to adopt fine particles having a refractive index different from that of the transparent resin material constituting the diffusion plate 6. Thereby, the light incident on the diffusion plate 6 is refracted by the fine particles, sufficiently scattered, diffused substantially uniformly, and emitted toward the optical sheet 7. In place of the fine particles, fine cavities containing air may be dispersed and mixed.
In addition, the exit surface of the diffusion plate 6 that emits light toward the optical sheet 7 is formed flat like the exit surface 12 of the light source unit 10 and the exit surface of the light control sheet 20.

  The optical sheet 7 is configured to transmit the light emitted from the diffusing plate 6 and to enter the liquid crystal display unit 3. The optical sheet 7 is formed, for example, in a rectangular shape in plan view, and has a light transmitting property, and a prism arranged on the light emitting surface of the light transmitting material 8 on the liquid crystal display unit 3 side. It consists of a lens unit 9.

  In the prism lens unit 9, for example, a plurality of unit prisms 9a having a triangular cross section and continuously extending in one direction (for example, a direction orthogonal to the paper surface in FIG. 1) are arranged in a direction orthogonal to the extending direction. The unit prisms 9a have a pitch larger than the wavelength of the light, collect light in a direction away from the liquid crystal display unit 3 that enters through the diffusion plate 6, and on the axis toward the viewer through the liquid crystal display unit 3. Turn around.

  In this way, when observing the liquid crystal display unit 3, the prism lens unit 9 increases the on-axis luminance by reducing the off-axis luminance. The on-axis here is a direction that coincides with the visual direction of the viewer, and is generally a normal direction to the display screen.

  When the repetitive array structure of the prism lens units 9 is arranged in only one direction, the direction change or recycling in the parallel direction is possible. In order to control the luminance of the display light in two directions orthogonal to each other in the horizontal plane, the two optical sheets 7 may be overlapped and combined so that the parallel directions of the unit prisms 9a group are substantially orthogonal to each other.

  The prism lens unit 9 is formed by a known extrusion molding method, injection molding method, or hot press molding method using, for example, PET, PC, PMMA, COP (cycloolefin polymer), acrylonitrile styrene copolymer, or the like. . In this case, the translucent base material 8 may be made of the same material as the translucent base material 21 in the light control sheet 20 described above, and may be made of a material different from the prism lens portion 9. The translucent substrate 8 and the prism lens portion 9 may be integrally formed from one substrate made of the same material.

  In addition, instead of the prism lens portion 9 as the optical sheet 7, an approximately semi-cylindrical lenticular lens or a microlens array arranged on the translucent substrate 8 may be adopted as the lens sheet.

Since the display device 1 according to the present embodiment has the above-described configuration, when the liquid crystal display unit 3 is illuminated by the backlight unit 2, when the LED array 14 in the housing 11 of the light source unit 10 is turned on, each display device 1 is individually turned on. According to the direction of the light distribution peak of the LED 15, most of the light emitted by the LED 15 does not go directly to the emission surface 12, but goes to the diffuse reflector 13a. In this way, in the process where the light reaches the diffuse reflector 13a, it passes through the air layer 17 and is appropriately scattered by the air layer 17 due to the contribution of the scattering effect.
Such light is reflected by the diffuse reflection plate 13a and diffused to a certain range, and then directly or after being reflected and diffused by the side diffuse reflection plate 13b, the emission surface 12 The light is emitted as surface emission. Also at this time, by passing through the air layer 17, it is diffused as appropriate due to the contribution of the diffusion effect.

As described above, the light emitted from the emission surface 12 of the light source unit 10 is dispersed and emitted over the entire emission surface 12, and passes through the light control sheet 20 so that the illuminance or luminance distribution is evenly distributed. The
The light that has passed through the light control sheet 20 enters the diffusion plate 6, is refracted and scattered by the fine particles, and enters the optical sheet 7 in a substantially uniformly diffused state.

  In the optical sheet 7, the light is refracted and condensed by the unit prisms 9 a arranged in the prism lens unit 9, and enters the liquid crystal display unit 3. Therefore, the light condensed by the liquid crystal display unit 3 has high axial brightness, and the peak width of the curve of the brightness distribution is appropriately widened so that the liquid crystal image can be visually recognized by the observer.

  In such a light source unit 10 in the display device 1, most of the light emitted from the individual LEDs 15 of the LED array 14 does not directly reach the emission surface 12, but propagates through the air layer 17 and diffusely reflects. The light is emitted from the emission surface 12 after being reflected by the plate 13a. Therefore, the light from the LED 15 can obtain a diffusing effect on the diffuse reflector 13a, and in the air layer 17 as the optical path length until the light emitted from the LED 15 is emitted from the emission surface 12 is increased. The contribution of the scattering effect can be sufficiently received.

  Therefore, since light can be effectively diffused and scattered, it is possible to reduce unnatural luminance unevenness of emitted light. That is, the light from the light source can be effectively converted into surface light emission without using a conventional light guide plate, so that it is possible to reduce the energy loss of light and improve the utilization efficiency, and The unit 10, the backlight unit 2, and the display device 1 can be reduced in weight and size.

  Further, by dispersing the irradiation position of each LED 15 on the diffuse reflector 13a of each LED 15 constituting the LED array 14, the light emitted from the emission surface 12 can be made more uniform, and better surface emission can be obtained. It becomes possible.

Next, a first modification of the first embodiment as described above will be described.
In this modification, as shown in FIG. 3, the diffuse reflectors 13 a disposed to face the back side of the emission surface 12 are arranged from the respective LED arrays 14 disposed at both ends in the width direction to the center in the width direction. It is arranged so as to incline toward the exit surface 12 side from the back side (see FIG. 3A) or from the exit surface 12 side to the back side (see FIG. 3B) as it is spaced apart. ing.

When the central part in the width direction of the diffuse reflector 13a is inclined so as to be close to the exit surface 12 as shown in FIG. 3A, the illuminance and luminance can be increased in the central part.
3B, when the central portion in the width direction of the diffusive reflector 13a is inclined so as to be separated from the emission surface 12, the illuminance and the luminance can be reduced at the center in the width direction. . Therefore, it is possible to appropriately adjust the illuminance and luminance according to the configuration of the light source unit 10, that is, the direction of the light distribution peak of each LED 15 constituting the LED array 14.

  Next, as a second modification of the first embodiment, for example, as shown in FIG. 4, an uneven portion 18 is provided at the irradiation position of light emitted from each LED 15 on the diffuse reflector 13 a. Also good. Thereby, the diffusibility in the diffuse reflector 13a can be improved, and the luminance unevenness of the light emitted from the emission surface 12 of the light source unit 10 can be reduced more effectively. In FIG. 4, the diffusive reflecting plate 13 a is provided with the concavo-convex portion 18 at the central portion in the width direction. Can be changed as appropriate.

  Next, the display apparatus 1 of 2nd embodiment of this invention is demonstrated using FIG. The display device 40 according to the second embodiment is different from the display device 1 according to the first embodiment in the configuration of the light source unit 30. In addition, about the component same as 1st embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  The housing 31 of the light source unit 30 in the second embodiment has a box shape that is rectangular in plan view, and the entire surface of the housing 31 on the display screen side is opened as an emission surface 32. Yes.

Further, as in the first embodiment, an LED array 34 in which a plurality of LEDs 35 are connected in series is used as the light source, but the LED 35 of this embodiment has a light distribution peak of emitted light facing one direction. Instead, the one having a light distribution peak that spreads radially on one surface centering on the LED 35 is employed.
As a method of providing a radial light distribution peak on one plane in this way, for example, a method of changing the shape of the lens itself by shaping the prism shape into the lens shape of the LED 35 or a separate optical element such as a prism. There is a method of attaching.
Further, a light blocking member 36 is attached to the lens surface of each LED 35 on the emission surface 32 side, and blocks light directed directly toward the emission surface 32.

  The LED array 34 configured in this manner extends in the housing 11 from the front side to the back side in FIG. 5 so that a plurality of LED arrays 34 are arranged in parallel across the entire width direction at a constant interval. Has been. At this time, each LED 35 is adjusted such that the light distribution peak radially spreads in the width direction around the LED 35.

The LED array 34 is immediately behind the LED array 34 as it moves away from the LED array 34 toward both sides in the direction intersecting the array direction of the LEDs 35, and from the back side to the exit surface 32 side. A diffusive reflecting material 33a that is inclined toward the surface is provided. By connecting such a diffuse reflection material 33a, a diffuse reflection plate 33 having a concavo-convex shape as a whole is formed, and the LED array 34 is disposed in the concave and convex portions of the diffusive reflection plate 33. Become.
Each of the diffuse reflectors 33a constituting the diffuse reflector 33 may be a curved plate having an arc surface curved in the width direction in addition to the flat plate shown in FIG. Moreover, the uneven | corrugated | grooved part 18 shown in the 1st modification of 1st embodiment may be formed on the diffuse reflection board 33. FIG.

  Further, in this LED array 34, as in the first embodiment, the irradiation position of the light emitted from each LED 35 is on each diffuse reflector 33a so that the light emitted from the emission surface 32 is uniform. The direction of the LED 35 is adjusted so as to change at.

  In addition, the inside of the housing 31 of the light source unit 30 configured as described above is an air layer 37 in addition to the above-described components.

As a modified example of the second embodiment, the light source may not be the LED array 34, but for example, a single LED 35 may be individually arranged as a point light source.
In this case, the LED 35 serving as a point light source is arranged in a matrix on one surface parallel to the emission surface 12 in the housing 31. And the diffuse reflection material 33a is inclined and arranged so as to surround each LED 35. As a result, the diffuse reflector 33 has a configuration in which concave portions having a quadrangular pyramid surface or a conical surface as a whole are arranged in a matrix, and a single LED 35 is arranged at the bottom top of each concave portion.
The diffuse reflector 33 may form not only a quadrangular pyramid surface and a conical surface, but also other polygonal pyramid surfaces such as a triangular pyramid surface and a hexagonal pyramid surface.

When the liquid crystal display unit 3 is irradiated by the backlight unit 2 in the display device 40 of the present embodiment, when the LED array 34 in the housing 31 of the light source unit 30 is turned on, the width direction is determined according to the direction of the light distribution peak of each LED 35. To be emitted. At this time, since each LED 35 is provided with the light blocking member 36, most of the light directly directed from the LED 35 toward the emission surface 32 is blocked by the light blocking unit 36.
Further, since each LED array 34 is provided in the concave portion of the diffuse reflector 33, the light emitted in the same plane as the width direction travels toward the diffuse reflector 33. Then, after being reflected by the diffusive reflecting plate 33 and diffused within a certain range, the light is emitted from the emission surface 32.
In addition, since the light radiated | emitted from LED35 propagates the air layer 37, it is scattered by the said air layer 37 suitably.

  Also in the light source unit 30 in the second embodiment, since the light of the LED 35 does not go directly to the emission surface 32 and passes through the diffusion reflection plate 33, the optical path length can be increased. The contribution of the scattering effect in the layer 37 can be sufficiently received. Therefore, it is possible to reduce unnatural luminance unevenness of the emitted light as in the first embodiment.

  In the second embodiment, since the LED arrays 34 are uniformly arranged over the entire width direction in the housing 31 of the light source unit 30, the first embodiment is provided with the light source only at the end in the width direction. Compared to the above, it is possible to more effectively reduce the luminance unevenness.

  Furthermore, as a modification of the light source unit 30 in the second embodiment, for example, a configuration as shown in FIG. 6 may be used. In this modification, the LED 35 emits light only to one side in the width direction (the right side in FIG. 6), and the diffuse reflector 33a is also inclined and arranged in the light emission direction of the LED 35 so as to correspond to it. This also makes it possible to perform surface light emission in which luminance unevenness is effectively reduced, as in the second embodiment.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the present invention. That is, the essence of the present invention is that the light source units 10 and 30 do not directly emit the light of the light source but emit the light through the diffuse reflectors 13 and 33 while propagating the air layers 17 and 37. Any embodiment is included as long as it is provided.

It is typical sectional drawing which shows schematic structure of the display apparatus which concerns on 1st embodiment of this invention. It is a front schematic diagram which shows arrangement | positioning of the light source of the light source unit in a display apparatus. It is typical sectional drawing of the light source unit by the 1st modification of 1st embodiment. It is typical sectional drawing of the light source unit by the 2nd modification of 1st embodiment. It is typical sectional drawing which shows schematic structure of the display apparatus which concerns on 2nd embodiment of this invention. It is sectional drawing which shows the modification of the display apparatus which concerns on 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Backlight unit 3 Liquid crystal display part 6 Diffusion plate 7 Optical sheet 10 Light source unit 11 Case 12 Output surface 13 Diffuse reflection plate 14 LED array (light source array)
15 LED (point light source)
16 Light blocking part 17 Air layer
20 Light control sheet 21 Translucent base material 22 Light reflection layer 23 Light reflection part 24 Opening part 30 Light source unit 31 Case 32 Outgoing surface 33 Diffuse reflection plate 33a Diffuse reflection material 34 LED array 35 LED
36 light blocking member 37 air layer

Claims (12)

In one light source unit configured to emit the light from the light source, the light source unit configured to emit the light from the entire emission surface,
A light source unit, comprising: a diffuse reflector that is disposed opposite to the back surface of the light exit surface via an air layer, wherein light from the light source is reflected by the diffuse reflector and emitted from the light exit surface. A light source array in which directional point light sources are arranged in series as the light source,
The light source array is arranged at the end in the width direction along the side of the emission surface so that the emitted light is directed toward the diffuse reflector,
The light source unit according to claim 1, wherein irradiation positions of light emitted from the point light sources on the diffuse reflector are dispersed.   As the diffuse reflector is separated from the light source array in a direction intersecting the arrangement direction of the respective point light sources, from the back side toward the exit surface side or from the exit surface side to the back side The light source unit according to claim 2, wherein the light source unit is an inclined surface inclined toward the surface. As the light source, comprising a light source array in which directional point light sources are arranged in series,
A plurality of the light source arrays are arranged at equal intervals in a direction orthogonal to the direction in which the point light sources are arranged,
The diffusive reflector is an inclined surface that is inclined from the back surface side toward the emission surface side as it is separated from each light source array in a direction perpendicular to the direction in which the point light sources are arranged. The light source unit according to claim 1.   The light source unit according to claim 4, wherein irradiation positions of light emitted from the point light sources on the diffuse reflector are dispersed. The light source is a directional point light source, and a plurality of light sources are arranged in a matrix on a surface parallel to the emission surface,
The light source unit according to claim 1, wherein the diffuse reflection plate forms a substantially quadrangular pyramid surface that individually surrounds each of the point light sources.   The light source unit according to any one of claims 2 to 6, wherein unevenness is provided at a position at an irradiation position by each of the point light sources on the diffuse reflection plate. The light source unit according to claim 2, wherein the point light source is an LED. The light source unit according to any one of claims 1 to 8,
A backlight unit, comprising: an optical sheet disposed opposite to the light emission surface side of the light source unit to control light emitted from the light emission surface.   The backlight unit according to claim 9, wherein a light diffusion plate mixed with light diffusion particles is provided between the light source unit and the optical sheet. Having a light transmissive substrate and a light reflection layer disposed on the incident surface side of the light transmissive substrate;
The light reflecting layer includes a light control sheet including an opening that transmits light and a light reflecting portion that reflects light.
In the area with high illuminance or brightness of light transmitted through the emission surface of the light source unit, the area of the opening of the light control sheet is reduced,
The backlight unit according to claim 9 or 10, wherein an area of the opening is set to be large in a region where illuminance or luminance is low.   The backlight unit according to any one of claims 9 to 11, and an image display unit that is disposed on an emission surface side of the optical sheet and displays an image using light from the backlight unit as display light. A display device characterized by comprising:

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