Patent Application
20150023052
N/A.
Backlights are used in displays such as liquid crystal displays (LCDs). Backlights add to the depth of the display. It is desirable to provide multiple LCD panels in a single housing. The panels may be arranged back-to-back to permit viewers on opposite sides of a table, for example, to view each of the displays. Each display, however, has its own backlight and thus the overall depth of such multi-display units is quite large.
In some embodiments, a two-sided light guide assembly that emits light out two sides of the assembly includes a light guide having a pair of opposing sides. The light guide assembly also includes a first light extraction layer provided on one side of the light guide. The first light extraction layer has light extraction features arranged in a first direction. A second light extraction layer also is provided on the other side of the light guide. The second light extraction layer has light extraction features arranged in a second direction orthogonal to the first direction. The light guide assembly also includes a first plurality of light sources provided along a third side of the light guide orthogonal to the pair of opposing sides and a second plurality of light sources provided along a fourth side of the light guide orthogonal to the pair of opposing sides and to the third side. Light from only the first plurality of light sources is extracted out the first light extraction layer and light from only the second plurality of light sources is extracted out the second light extraction layer.
In some embodiments, a two-sided light guide assembly that emits light out two sides of the assembly includes a light guide having a pair of opposing sides. The assembly includes a first light extraction layer provided on one side of the light guide. The first light extraction layer has a first plurality of light extraction features and a reflective material in interstitial spaces between the first plurality of light extraction features. A second light extraction layer also is provided on the other side of the light guide. The second light extraction layer has a second plurality of light extraction features and a reflective material in interstitial spaces between the second plurality of light extraction features. A first plurality of light sources is provided along a third side of the light guide orthogonal to the pair of opposing sides and a second plurality of light sources provided along a fourth side of the light guide orthogonal to the pair of opposing sides and to the third side. Light from only the first plurality of light sources is extracted out the first light extraction layer and light from only the second plurality of light sources is extracted out the second light extraction layer. The reflective material is not in contact with the light guide.
Yet other embodiments are directed to a monitor assembly including a two-sided light guide assembly that includes a light guide and first and second light extraction layers positioned on opposing sides of the light guide. Each light extraction layer comprises a plurality of light extraction features configured to cause light to be extracted from the light guide. The monitor assembly includes a first display panel configured to receive light extracted from the light guide by the first light extraction layer and a second display panel configured to receive light extracted from the light guide by the second light extraction layer. A reflective material is provided in interstitial spaces between the light extraction features of each of the first and second light extraction layers. The reflective material not in contact with the light guide. Light is extractable out one light extraction layer independent of the other light extraction layer.
For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:
The drawings are not drawn to scale.
The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
In accordance with various embodiments, a multi-display system is disclosed that includes a single, two-sided backlight assembly between display panels facing opposing directions. The two-sided backlight assembly is able to emit light in two light paths generally 180 degrees apart—one light path passes through one of the display panels and another light pass through the other of the display panels. That is, the two-sided light guide assembly emits light out two sides and generally in opposite directions. The two-sided backlight assembly uses lights such as light emitting diodes (LEDs) mounted on the side of a light guide thereby permitting the backlight assembly to be relatively thin. Because a single, thin, two-sided backlight assembly is used, the overall depth of the multi-display system is less than would be the case if two separate backlight assemblies were used.
The extraction layers 144 and 148 may be films that are adhered to the light guide 140. Alternatively, the extraction layers may be formed directly on the light guide 140.
Two pluralities of light sources (preferably LEDs) are provided along at least two of sides 154, 164, 168, and 170. If only two sides of the light guide are used for light sources, the two sides preferably are orthogonal to each other. As shown in
The light extraction features 180 will only extract light inside the light guide 140 that is transmitted in a direction generally normal to the long dimension of the light extraction features (e.g., direction 185 in
Preferably, the light extraction layers 144, 148 are provided on opposing sides of the light guide 140 so that the light extraction features of one light extraction layer are arranged in a direction orthogonal to the direction of the light extraction features of the other light extraction layer.
Referring again to
In
In
The plurality of light sources 150 may be provided on one side or two opposing sides of the light guide 140. Similarly, the plurality of light sources 160 also may be provided on one or two opposing sides. Further, one plurality of light sources may have light sources on only one side while the other plurality of light sources may be on two sides.
In the example of
In general, two sets of light sources are provided which inject light into the light guide 140 in orthogonal directions. Two sets of light extraction features 180 are provided on light extraction layers 144, 148 on opposing sides of the light guide. The two sets of light extraction features are oriented orthogonal to each other. Thus, light from only one set of light sources (i.e., light sources on only a single side of the light guide or on opposing sides) is extracted out one of the light extraction layers, while light from only the other set of light sources is extracted out the other light extraction layer. For example, light only from light sources 160 may be extracted out of light extraction layer 148, while light only from light sources 150 may be extracted out of light extraction layer 144.
The light extraction features 180 on light extraction layer 148 are oriented orthogonal to the direction light travels in the light guide 140 from light source 160 and cause light from light source to be extracted from the light guide 140. The light extraction features on light extraction layer 144 are oriented parallel to the direction of light travel from light source 160 and thus do not extract light from light source 160. A light ray 210 is depicted. The light ray reflects off the bottom surface of the light guide and encounters a light extraction feature 180. The relative difference in indices of refraction of the light guide 140 and light extraction features 180 is such that light passes from the light guide and into the light extraction feature 180, reflects off a side surface of the light extraction feature, passes through the diffuser 202, reflects off BEF 200, reflects off a reflection layer (discussed below) impregnated into the light extraction layer and finally through the LCD panel 110. The same process occurs for light extraction layer 144 but with the orthogonally arranged set of light sources 150.
Each set of light sources 150 and 160 is independently controllable by controller (e.g., a video controller of a computer).
As can be seen in
The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
