Patent Application
20150253492
An embodiment relates to a lighting apparatus and a display apparatus.
Conventionally, a flexible display apparatus using an organic light emitting diode (OLED) has been developed. However, the OLED has problems such as a high manufacturing cost and a short life, which has recently led to a proposal to a flexible liquid crystal display apparatus.
A liquid crystal element is not self-luminous, and hence the liquid crystal display apparatus requires a lighting apparatus (backlight unit) for illuminating a liquid crystal display panel from the behind. The lighting apparatus also needs to be flexible. As such a lighting apparatus, there is known a lighting apparatus configured such that a board (LED bar) having a light emitting diode (LED) light source disposed thereon, is disposed on a side of a flexible light guide plate.
However, the LED bar is not flexible. Accordingly the lighting apparatus can be bent in a direction parallel to a side where the LED bar is disposed, but cannot be bent in a direction perpendicular thereto, which restricts bending flexibility.
An embodiment provides a lighting apparatus including a flexible first light guide member having a rectangular shape with at least one corner chipped; and a first light source that is disposed at a position of the chipped corner of the first light guide member and emits light to the first light guide member.
Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.
The light guide plate 1 is a flexible sheet made of urethane, soft acrylic resin, or the like, and thus has a high flexibility. In addition, the light guide plate 1 desirably has a high transparency to light of any wavelength. The light guide plate 1 has a rectangular shape with at least one corner chipped. As an example, the light guide plate 1 has a square shape of 225 mm on a side with the four corners cut in a straight line. The light guide plate 1 may be obtained by forming the above materials into a shape illustrated in
A scattering mark (unillustrated) for extracting light is formed on an upper surface and/or a lower surface of the light guide plate 1 using white ink. If the light guide plate 1 is weak to heat, the scattering mark is desirably formed by ink jet printing without the need of baking. The scattering mark is designed so that the lighting apparatus 10 emits uniform light upward. For example, the scattering marks are provided such that the farther away from the LED light source 2 is, the higher the density is.
The LED light source 2 is disposed at a position of each chipped corner of the light guide plate 1. Then, the LED light source 2 emits light diagonally toward the center from an edge of the light guide plate 1 in the same plane as the light guide plate 1. The LED light source 2 desirably emits light perpendicularly to the edge. The LED light source 2 may be configured of only white LED to suppress cost, or may be configured of LEDs for emitting light at each wavelength of RGB to enhance the expressive power of colors. Note that the LED light source 2 may be of a side-view type or may be of a top-view type.
If the LED light source 2 is disposed horizontally along a side of the light guide plate 1, the lighting apparatus 10 cannot be bent vertically. Likewise, if the LED light source 2 is disposed vertically along a side of the light guide plate 1, the lighting apparatus 10 cannot be bent horizontally.
In contrast to this, the present embodiment disposes the LED light source 2 in a corner of the light guide plate 1. Therefore, the lighting apparatus 10 that is flexible and has a high bending flexibility can be obtained.
The light source case 11 is made of a flexible material. Then, the LED bar 12, the reflective sheet 13, the light guide plate 1, the luminance control sheet 14, and the optical sheet 15 are laminated in this order inside the light source case 11. The end portion of each side of the optical sheet 15 and the inner side wall of the light source case 11 are sealed with a tape.
The tape may be a colored tape according to the application or may be a tape for optical applications with high transparency. In addition, the light source case 11 may be made of a transparent material according to the application or may be made of a white material to increase the use efficiency of light from the LED light source 2. Alternatively, the entire light source case 11 or the inner side wall thereof may be painted white.
In addition, a wiring hole (unillustrated) is formed on a rear surface of the light source case 11, and a power supply line 2a of the LED 2 is drawn to outside. Thus, the power supply line 2a is drawn out not from the side surface of the lighting apparatus 10 but from the rear surface thereof. As a result, the bezel for hiding the power supply line 2a behind the outer periphery of the lighting apparatus 10 can be formed very thin (or eliminated).
The LED light source 2 is fixed to the LED bar 12 as a board. Then, the LED bar 12 is fixed to the light source case 11 using a screw or a double-sided tape so that light from the LED light source 2 is incident on an edge of the light guide plate 1. More specifically, if the LED light source 2 is of a side-view type, as illustrated in
In order to suppress a hot spot from occurring near the light source of the light guide plate 1, a lens may be disposed in front of the LED light source 2, or a seal on whose surface a prism is formed may be attached to an end surface on which a light beam of the light guide plate 1 is incident.
The reflective sheet 13 is disposed on a bottom surface of the light guide plate 1. Then, the reflective sheet 13 reflects light emitted from the light guide plate 1 to the rear surface back toward the light guide plate 1, which enhances the light use efficiency.
The light guide plate 1 guides the light emitted from the LED light source 2 and light reflected by the reflective sheet 13 upward.
The luminance control sheet 14 is obtained, for example, by silk-printing a reflection pattern or a scattering pattern on the rear surface of a PET (Polyethylene Terephthalate) sheet with an ink that is white and has a high reflectance. The luminance control sheet 14 reduces brightness unevenness due to leakage light around the LED light source 2.
The optical sheet 15 includes a dual brightness enhancement film (DBEF), a brightness enhancement film (BEF), a diffusion sheet, and the like. Micro holes may be provided in the diffusion sheet by dot printing to scatter leakage light emitted directly above from the LED light source 2.
Note that in order to reduce cost, the reflection pattern or the scattering pattern may be printed on the rear surface of the diffusion sheet contained in the optical sheet 15 thereby to integrate the luminance control sheet 14 and the optical sheet 15.
Note also that two or more light guide plates 1 may be incorporated into the light source case 11, which can increase the number of LED bars 12 as much as possible.
In this case, the scattering pattern is printed so that the energy of light emitted from the LED light source 2 is completely consumed near the center. Thus, the light emitted from the LED light source 2 reaches near the center of the light guide plate 1, but very few light reaches beyond that. The energy of light is almost completely consumed at an inflection point of the center, which can suppress brightness unevenness from occurring due to a light beam emitted from the light guide plate 1 without satisfying the total reflection conditions from near the inflection point when the lighting apparatus 10 is bent.
As described above, the first embodiment includes the light guide plate 1 having a shape with a chipped corner, and disposes the LED light source 2 in the chipped corner. Therefore, the bending flexibility of the lighting apparatus 10 can be increased.
Note that
In the above described first embodiment, the brightness in the back of the LED light source 2 may be reduced. However, the reduction in brightness in the back of the LED light source 2 needs to be suppressed depending on the application of the lighting apparatus. In light of this, there follows a description of the second embodiment for suppressing the reduction in brightness in the back of the LED light source 2.
Further, as illustrated by the lighting apparatus 10b in
As another example, as illustrated by the lighting apparatus 10c in
As described above, the second embodiment can suppress the reduction in brightness in the back of the LED light source 2.
By the way, an OLED is known as the flexible lighting apparatus. The description will focus on the advantage of the lighting apparatus according to the present embodiment using an LED as the light source in comparison with the OLED.
In general, the OLED has a low brightness and light-emitting efficiency as well as a short life. In contrast to this, the present embodiment can increase the brightness and light-emitting efficiency as well as life using the LED light source.
In addition, the OLED manufacturing technique has not been established, and thus the OLED manufacturing cost is high and the yield is low. In contrast to this, the present embodiment can manufacture the LED light source in a stable manner using an established manufacturing technique. As a result, the lighting apparatus manufacturing cost can be suppressed.
Further, it is difficult to increase the size of the OLED. When the size of the OLED is to be increased by tiling, joints become noticeable at tiling because the outer periphery of the OLED includes a non-light emitting region of about 5 to 10 mm. In contrast to this, the present embodiment can greatly reduce the thickness of the bezel (or eliminate the bezel) by drawing the power supply line 2a of the LED light source from the rear surface. As a result, the present embodiment can prevent the joints from being noticeable at tiling.
In addition, the present embodiment can exhibits high color rendering properties comparable to the OLED using the LED light source emitting light of each wavelength of RGB.
Various applications can be considered for each lighting apparatus described above.
The liquid crystal display panel 31 is also flexible and can be bent vertically and horizontally at the same time as illustrated in
Note that the liquid crystal display apparatus may be configured to include any one of the lighting apparatuses 10a to 10c.
Such a liquid crystal display apparatus 100 can be used by bending so as to surround the viewer. Thus, the field of view of the viewer is covered with the liquid crystal display apparatus 100, which improves reality of the image displayed. In particular, the liquid crystal display apparatus 100 can be considered applicable to an arcade game device such as a shooting game.
Note that the corners of the lighting apparatuses 10b are positioned at the center of the display system 200. Therefore, the lighting apparatus 10b capable of suppressing the reduction in brightness at the center is desirably used. Then, instead of the light guide plate 22 of the triangular prism, a square-shaped flexible light guide plate 23 may be disposed at the center of the display system 200. In order to enhance the light use efficiency, a white reflective tape is desirably attached to the side surface of the light source case 11.
In addition to the above, the lighting apparatus can be considered applicable to a curved surface such as being wrapped around a cylindrical pillar or attached to the ceiling of a car.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fail within the scope and spirit of the inventions.
This application is based upon and claims the benefit of priority from U.S. Provisional Application No. 61/948,380, filed Mar. 5, 2014; the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61948380 | Mar 2014 | US |
