Patent Application
20200124918
The present invention relates to a lighting apparatus including an optical member in a front surface of a light source, and a liquid crystal display apparatus.
A liquid crystal display apparatus of a transmission type needs a lighting apparatus that radiates light from a back surface of a liquid crystal panel in which an image is displayed. As the lighting apparatus, there are a lighting apparatus of an edge light type and a lighting apparatus of a direct type. The lighting apparatus of the edge light type guides light emitted from a light source arranged in an edge surface of a light guide plate and performs planar light emission. The lighting apparatus of the direct type has a plurality of light sources arranged directly below a liquid crystal panel with a predetermined interval and performs planar light emission.
A technique called “HDR” that achieves an extremely wide dynamic range has been increasingly adopted in recent years. The HDR is able to be achieved by performing driving of partial lighting called local dimming in the lighting apparatus of the direct type. Further, in the lighting apparatus of the direct type, many light sources are able to be arranged, so that high luminance is also easily achieved.
In general, in the lighting apparatus of the direct type, many light sources are arranged with a predetermined pitch and an optical member for diffusing light is arranged at a position facing each of the light sources. Meanwhile, when trying to achieve high luminance in the lighting apparatus of the direct type, the number of light sources increases and the optical member is apt to be affected by heat generated from the light source. Thereby, the optical member is bent, which causes luminance unevenness. Further, when the optical member is bent, the optical member and the light source contact, which causes damage of the light source. In addition, for use in a vibrational situation such as on-vehicle use, the optical member and the light source contact and the light source may be damaged.
As means of solving such a problem in the lighting apparatus of the direct type, for example, PTL 1 proposes a method of preventing an optical member from being bent by providing a support body in a gap between a plurality of light sources that are arranged.
For appropriately supporting a diffuser plate that is an optical member, the support body as described above is fixed by a fixing protrusion being inserted into a fixing hole provided in an under chassis. In order to avoid a case where shadow is formed due to light emitted from a light source being blocked by the support body, the support body is formed to be tapered as much as possible and is generally in point contact with the diffuser plate.
[PTL 1] Japanese Unexamined Patent Application Publication No. 2013-161793
Meanwhile, as an HDR-compatible lighting apparatus of the direct type has higher luminance, approaches have been recently made to mount light sources on a substrate so that a pitch of the light sources is as narrow as possible. However, since the light sources are arranged with the narrow pitch, it is difficult to secure a space where a support body is installed.
A general support body is manufactured by resin molding using a mold and there is limitation to size reduction. Moreover, even when the molding is able to be performed, an insert portion by which the small support body is fixed onto the substrate becomes too thin and is broken during use in some cases. Further, though fixation with use of tape or adhesive is also considered, an adhesive force is insufficient because an adhesive area is small, so that it is difficult to perform fixing firmly.
An embodiment of the invention aims to provide a lighting apparatus and a liquid crystal display apparatus in which an optical member is not bent even when a plurality of light sources are arranged with a narrow pitch.
(1) An embodiment of the invention is a lighting apparatus including: a substrate; a plurality of light sources each of which has a light output surface and which are arranged on the substrate; an optical member that is arranged at a position facing the light output surface of each of the light sources; and a support body that supports the optical member and has a height from a surface of the substrate higher than a height to the light output surface, in which the support body is arranged between the substrate and the optical member, and includes a support part that has a light transmission property and an opening corresponding to at least one of the plurality of light sources as viewed from a direction normal to the substrate.
(2) Moreover, an embodiment of the invention is the lighting apparatus in which the support body includes an adhesive layer arranged between the support part and the substrate, in addition to the configuration of (1) described above.
(3) Moreover, an embodiment of the invention is the lighting apparatus in which the support body includes a reflection layer arranged between the support part and the adhesive layer, in addition to the configuration of (2) described above.
(4) Moreover, an embodiment of the invention is the lighting apparatus in which the support body includes an insulating reflection surface arranged between the support part and the substrate, in addition to the configuration of (1), (2), or (3) described above.
(5) Moreover, an embodiment of the invention is the lighting apparatus in which the support part includes a top surface part provided at a top surface, in addition to the configuration of (1) described above.
(6) Moreover, an embodiment of the invention is the lighting apparatus in which the top surface part contacts the optical member, in addition to the configuration of (5) described above.
(7) Moreover, an embodiment of the invention is the lighting apparatus in which the adhesive layer has a light transmission property, in addition to the configuration of (2) described above.
(8) Moreover, an embodiment of the invention is the lighting apparatus in which a thickness of the reflection layer is 0.1 to 10 μm or less, in addition to the configuration of (3) described above.
(9) Moreover, an embodiment of the invention is the lighting apparatus in which a shape of the opening is circular as viewed from the direction normal to the substrate, in addition to the configuration of (1), (2), or (3) described above.
(10) Moreover, an embodiment of the invention is the lighting apparatus in which at least any one of a light input surface which faces the light source in the optical member and the top surface part is a rough surface, in addition to the configuration of (5) described above.
(11) Moreover, an embodiment of the invention is the lighting apparatus in which a side surface of the support body in the opening has an uneven surface, in addition to the configuration of (1), (2), or (3) described above.
(12) Moreover, an embodiment of the invention is the lighting apparatus in which the support part contains a scattering particle, in addition to the configuration of (1), (2), or (3) described above.
(13) Moreover, an embodiment of the invention is the lighting apparatus in which at least two or more support bodies are arranged, in addition to the configuration of (1), (2), or (3) described above.
(14) Moreover, an embodiment of the invention is the lighting apparatus in which the support body has the plurality of light sources all of which are arranged in the opening, in addition to the configuration of (1), (2), or (3) described above.
(15) Moreover, an embodiment of the invention is the lighting apparatus in which the support body has a plurality of openings, in addition to the configuration of (1), (2), or (3) described above.
(16) Moreover, an embodiment of the invention is the lighting apparatus in which two or more of the plurality of light sources are arranged in the at least one opening, in addition to the configuration of (1), (2), or (3) described above.
(17) Moreover, an embodiment of the invention is the lighting apparatus in which the support body is arranged in a striped pattern in the substrate, in addition to the configuration of (1), (2), or (3) described above.
(18) Moreover, an embodiment of the invention is a liquid crystal display apparatus including a display panel in the lighting apparatus, in addition to the configuration of (1), (2), or (3) described above.
According to an embodiment of the invention, even when a plurality of light sources are arranged with a narrow pitch, an optical member is prevented from being bent.
The present embodiment will be described with reference to
As illustrated in
Though detailed components are not illustrated in the figure, the liquid crystal panel 11 has a configuration in which a pair of glass substrates are bonded with a predetermined gap therebetween and liquid crystal is enclosed between both of the glass substrates.
The lighting apparatus 2 is arranged in a plate surface side opposite to a display surface of the liquid crystal panel 11. The lighting apparatus 2 includes an optical member 6, a support body 7, a light source 1, a substrate 3, and a frame 4.
(Optical Member)
The optical member 6 is arranged at a position facing the light source 1. The optical member 6 is a member that realizes a surface light source by making light emitted from the light source 1 uniform. Specific examples thereof include optical members such as a fluorescence light emission sheet (such as QDEF manufactured by 3M Company), a diffuser plate (such as a SUMISPEX opal plate manufactured by Sumitomo Chemical Co., Ltd), a diffuser sheet (such as D114 manufactured by TSUJIDEN Co., Ltd.), a prism sheet (such as BEF manufactured by 3M Company), and a polarization reflection sheet (such as DBEF manufactured by 3M Company). Moreover, such optical members 6 are layered in order of the fluorescence light emission sheet, the diffuser sheet, the prism sheet, and the polarization reflection sheet. Note that, in a case where a color of light emitted from the light source 1 is blue, the fluorescence light emission sheet is required. Thereby, high luminance is obtained.
(Substrate)
(Light Source)
As illustrated in
The light source 1 is connected to the substrate 3 by solder. The lighting apparatus 2 in which the light source 1 is mounted on the substrate 3 by solder is able to be manufactured by, for example, a general reflow solder process or the like.
(Frame)
As illustrated in
Meanwhile, for achieving high luminance in the lighting apparatus 2 of the direct type, by increasing the number of light sources 1 to be arranged, a high effect is obtained. However, when the number of light sources increases, an arrangement pitch is narrowed, so that the support body is difficult to be arranged as in a general lighting apparatus of a direct type. Thus, the support body 7 in the present embodiment has the following configuration.
(Support Body)
At least one or more support bodies 7 are arranged in the substrate 3 and the support body 7 is constituted by a support part 5. An opening 15 is open in a light output direction so as to correspond to at least one light source 1 as viewed from the direction normal to the substrate 3. The opening 15 is formed into the same shape as or a shape of almost the same type as the shape of the light source 1 in accordance with the shape of the light source 1. Note that, the opening 15 is formed by mold processing or drill processing.
That is, the support body 7 is arranged so as to surround at least one light source 1. For example, there is a case where the support body 7 surrounds two light sources 1 or the support body 7 surrounds a column of light sources 1. Further, a plurality of support bodies 7 are able to be arranged in the substrate 3. Such a configuration makes it possible to easily change design of the support body 7.
Examples of a shape of the support body 7 include square, rectangular, circular, rhombic, triangular shapes each having the opening 15 in a center part in plan view.
A distance between the light source 1 and a side surface of the support body 7 in the opening 15 will be described with reference to
As illustrated in
As illustrated in
The support part 5 has a top surface part 16 provided at a top surface and further has a light transmission property. Such a configuration makes it possible to minimize attenuation of light incident from the side surface of the support part 5 in the opening 15. Thereby, the usage efficiency of light is able to be enhanced. Examples of a main material by which the support body 7 has a light transmission property include acryl, polycarbonate, and PET.
In the present embodiment, as illustrated in
Further, the support part 5 of the support body 7 has a columnar shape in sectional view. Thereby, it is possible to support the optical member 6 more stably.
(Manufacturing Method)
The support body 7 in the present embodiment is able to be manufactured as follows.
First, an optical sheet that is transparent and is thicker than the light source 1 is prepared (for example, a transparent polycarbonate sheet having a thickness of 0.3 mm). Then, the optical sheet is cut to have a size surrounding at least one light source 1 of a plurality of light sources 1. Next, an opening is provided at a portion corresponding to the light source 1 by mold processing. Further, the resultant is arranged in the substrate 3 so that the opening and the light source 1 match. As a result, the support body 7 in the present embodiment is able to be manufactured.
When the support body 7 in the present embodiment is provided, the optical member 6 is able to be supported and breakage of the light source 1 is able to be avoided. A high effect is exerted particularly in use, such as on-vehicle use or use in a mobile device, in which vibration is generated. It is also possible to prevent the optical member 6 from being locally bent and reduce luminance unevenness.
In addition, when trying to achieve reduction in thickness of a liquid crystal display apparatus including a normal lighting apparatus, a distance between a light source and an optical member is short and a problem of luminance unevenness is posed. In a case of the liquid crystal display apparatus 10 including the lighting apparatus 2 in the present embodiment, however, the plurality of light sources 1 are able to be arranged with a narrow pitch, thus making it possible to achieve reduction of the thickness.
A modified example of the first embodiment will be described with reference to
The top surface part 16 of the support body 7 may contact the optical member 6 arranged at the position facing the light source 1 as illustrated in
The present embodiment will be described with reference to
The present embodiment is different from the first embodiment in that a lighting apparatus 12 has a support body 17 including an adhesive layer 19 between the support part 5 and the substrate 3. That is, the support body 17 in the lighting apparatus 12 has the support part 5 and the adhesive layer 19.
The adhesive layer 19 in the present embodiment is arranged in at least a part of the substrate 3 as illustrated in
Moreover, the adhesive layer 19 preferably has a light transmission property. Such a configuration makes it possible to prevent light from being absorbed in a surface or inside of the adhesive layer 19. Thereby, the usage efficiency of light is able to be enhanced.
The present embodiment will be described with reference to
The present embodiment is different from the second embodiment in that a lighting apparatus 22 has a support body 27, which includes a reflection layer 20, between the support part 5 and the adhesive layer 19. That is, the support body 27 in the lighting apparatus 22 has the support part 5, the reflection layer 20, and the adhesive layer 19.
As illustrated in
As the reflection layer 20 in the present embodiment, white coating, a metal thin film made of aluminum, silver, or an alloy including them that has a high reflectance and is thin, a dielectric multilayer film in which light-transmissive materials having different refractive indexes are alternately layered, or the like is considered. In the present embodiment, since the thinner thickness enables to enhance the usage efficiency of light, the metal thin film is most preferably used. The thickness of the reflection layer 20 in this case is, for example, 0.1 μm to 10 μm or less.
The support body 27 in the present embodiment is able to be manufactured as follows. Note that, the same step as that of Embodiment 1 will be omitted.
First, silver is vapor-deposited with a thickness of 0.2 μm on one surface of an optical sheet. In this case, coating for increasing adhesiveness, a protection layer for protecting silver, a reflection enhancing film, or the like may be provided on a sheet side as needed. Then, an adhesive layer is applied onto a silver thin film and a release sheet is further attached thereto. Next, an opening is provided at a portion corresponding to the light source 1 by mold processing. Further, the release sheet is released to expose the adhesive layer and the resultant is attached to the substrate 3 so that the opening and the light source 1 match. As a result, the support body 27 in the present embodiment is able to be manufactured.
Note that, in the present embodiment, in a case where the reflectance of the reflection layer 20 is high, even when the adhesive layer is colored, the usage efficiency of light is not affected, so that the adhesive layer is able to be selected from a wider range and a more reliable material or the like is also able to be used.
The present embodiment will be described with reference to
The present embodiment is different from the first embodiment in that a lighting apparatus 32 has a support body 37 that includes an insulating reflection surface 21 between the support part 5 and the adhesive layer 19. That is, the support body 37 in the lighting apparatus 32 has the support part 5 and the insulating reflection surface 21.
The insulating reflection surface 21 is obtained by coating the substrate 3 in white by white resist. The white coating is applied to a surface other than the electrode part 14. Thereby, the usage efficiency of light is able to be enhanced. Note that, the conductive pattern 8 is required to be an insulating material so as to be coated in white.
The present embodiment will be described with reference to
The present embodiment is different from the first embodiment in that at least one of a light input surface 6a of the optical member 6 and the top surface part 16 contacting the light input surface 6a is a rough surface 23 in a lighting apparatus 42. The light input surface 6a is a surface facing the light source 1 in the optical member 6. A roughness range of the rough surface 23 is, for example, Ra=0.2 μm to 10 μm. Such a configuration makes it possible to prevent Newton's rings that occur when the support body 7 and the optical member 6 are close contact at the interface. The Newton's rings refer to a concentric dark and light striped pattern that is seen as viewed from the direction normal to the substrate 3. Thereby, the usage efficiency of light is able to be enhanced. Note that, the rough surface 23 may be rephrased by matte, matting, non-glare, antiglare, or the like.
Moreover, when the top surface part 16 is the rough surface, an effect of extracting light that is incident from an edge surface of the support part 5 and guided into an inside is enhanced, thus making it possible to enhance the usage efficiency of light.
In addition, even a configuration in which the support body 7 and the optical member 6 are attached through adhesive without an air interface makes it possible to prevent occurrence of Newton's rings.
The present embodiment will be described with reference to
The present embodiment is different from the first embodiment in that a side surface of the support body 7 in the opening 15 has an uneven surface 24 in a lighting apparatus 52. Such a configuration makes it possible to enhance an effect of extracting light guided into an inside, so that the usage efficiency of light is able to be enhanced.
The present embodiment will be described with reference to
The present embodiment is different from the first embodiment in that the support pat 5 in a lighting apparatus 62 contains a scattering particle 25. Such a configuration makes it possible to achieve an effect of extracting light. Thereby, the usage efficiency of light is able to be enhanced.
The present embodiment will be described with reference to
The present embodiment is different from the first embodiment in that a support body 57 is formed in an entire surface of the substrate 3 as viewed from the direction normal to the substrate 3. That is, the support body 57 has a plurality of light sources 1 all of which are arranged in openings 15. Such a configuration makes it possible to arrange the support body 57 with a relatively wide area even when the light sources 1 are arranged with a narrow pitch. As a result, the optical member 6 is able to be supported without providing a fixing part in the support body 57.
An aspect in which a support body 67 is disposed on the substrate 3 will be described as another embodiment with reference to
As illustrated in
Further, as illustrated in
The invention is not limited to the embodiments described above and can be carried out in other various forms. The embodiments are therefore to be taken in all respects as exemplary only, and are not to be interpreted as being limiting. The scope of the invention is represented by the scope of the claims and is not restricted in any way to the specification itself. Furthermore, all variations and modifications falling within a range equivalent to the scope of the claims also fall within the scope of the invention.
| Number | Date | Country | |
|---|---|---|---|
| 62749051 | Oct 2018 | US |
