Battery saver: BlackBerry Patent app describes screen illuminated by ambient light

A new BlackBerry Patent application details a way for a (you guessed it) BlackBerry device to harness ambient light in order to illuminate the device to a degree and in a manner appropriate to the immediate surroundings.That would be ambient light, and not the type of device-generating, battery-draining light you see in a backlit screen.
Written by Russell Shaw, Contributor

A new BlackBerry Patent application details a way for a (you guessed it) BlackBerry device to harness ambient light in order to illuminate the device to a degree and in a manner appropriate to the immediate surroundings.

That would be ambient light, and not the type of device-generating, battery-draining light you see in a backlit screen.

The app's title is: System and Method For Providing Ambient Light In An Electronic Device. As with so many other patents, the Abstract gives us a window on just what is being devised:

The invention provides a device and method for providing backlight to a display in an electronic device. The device comprises: a housing; an ambient light collector; a backlight panel; a shutter; and a photodetector. The ambient light collector has: a body having the first end and a second end, which is located within the housing. The body receives ambient light from around the electronic device and transmits it to the second end. The body is shaped to direct the ambient light from the first end towards the second end and has a turn in it between the first and second ends. In the body, each conduit has an upper end and a lower end, the upper end being connected to the second end of the body, and each conduit extending downward and away from the second end.

I have three sketches from the Patent application to show you, as well as descriptive narrative for each. So follow along and let me, um, "shed some light" on how this technology would work:

Referring to FIG. 3, ambient environment 300 is shown wherein two devices 10A and 10B of an embodiment are being used by persons 302A and 302B respectively. Ambient light source 32 is located between persons 302A and 302B; source 32 is may be the sun or a mounted artificial light.

Device 10A is located between person 302A and ambient light source 32. Person 302B is located between device 10B and ambient light source 32. Even in environment 300, devices 10A and 10B have different lighting situations, providing different visibility conditions for their respective displays 14A and 14B.

As display 14A of device 10A faces away from source 32, person 302A is viewing display 14A with indirect reflected light from source 32. Display 14B receives direct light from source 32. Indirect light from source 32 is less bright than direct light. As such, the ambient contrast for display 14A is better than the contrast for display 14B, making display 14A easier to read.

Generally, there are two methods of improving the ambient contrast for a display, such as display 14A and 14B: either decrease its ambient light or increase its backlighting. Backlighting provides a light source emanating from behind a transmissive display (such as an LCD).

Known backlighting systems utilize powered light sources. However, such sources consume battery power. The embodiment collects and redirects ambient light, such as light from source 32, as a backlight for its display.

For more details, let's look at Figs 4 and 5, and then read about them in tandem:


Referring to FIGS. 4 and 5 further aspects of an embodiment are shown. In particular, backlight system 30 has three main sections: ambient light collector section 402; active light generator section 404 and backlight panel 406.

Both the ambient light collector section 402 and the active light generator section 404 are connected to the panel 406. The connections linking sections 402 and 404 to panel 406 provide a physical transmission channel for light to be transmitted from either section to the panel 406.

Ambient light collector section 402 collects ambient light from outside of device 10 and transmits the collected ambient light to backlight panel 406.

Active light generator section 404 houses light sources 408 and transmits light generated by the active light sources 408 to backlight panel 406. Backlight panel 406 distributes the light received from sections 402 and 404 and disperses it through the back panel of display 14, through its panels, providing backlighting to display 14.

Generally, to assist in the transmission of light, ambient light collector section 402 and backlight panel 406 are each a shaped volume that collects light energy at one end, transmits the energy "forward" through an internal channel in the volume and provides the transmitted light energy out a second end. Each section may be formed from a transparent or translucent material, allowing light to be transmitted forward within its volume.

Clear plastic or lexan (trade-mark) may be used to form light transmissive sections of backlight system 30. The interior sides of the sections may be coated with a light reflective material in order to assist in the internal transmission of the light energy. Further, dimensions, angles and contours within the sections may be formed to facilitate the forward transmission of the light energy and to reduce the amount of light reflected backwards towards the source following known light transmission principles.

Arrows 410 show a general path of ambient light received by ambient light collector section 410 as the light is transmitted through the sections of backlight system 30 and then through display 14. Further detail on each section is provided below.

Ambient light section 402 comprises lens 414, body section 416 and light transmission conduits 418, forming one integral body. Each section may be formed separately, then joined, melted or welded together at the mating seams of the sections using techniques known in the art. Having an integral body is preferable, as there can be loss of light energy as a light is transmitted between through boundaries between sections.

When device 10 is assembled, ambient light collector section fits into upper housing 12A such that lens 414 mates with opening 412 in upper housing 12A. Opening 412 spans a top portion of upper housing 12A along its front face and top edge. In the embodiment, lens 414 is generally an oblong body, having a flat upper surface which mates with opening 412. Body section 416 is a shaped oblong.

Lens 414 is located at one end of the shaped oblong. Exterior surfaces of body section 416 are defined to reflect light received from lens 414 through body section 416. In the embodiment, a lower surface of the shaped oblong underneath lens 414 is shaped to provide a taper to allow light received through lens 414 to be directed through a turn towards the length of the body of section 416.

At the end of body section 416 are two further tapers 432 which collect the received light and concentrate it towards light transmission conduits 418. Light transmission conduits 418 are generally columniform. Each conduit is attached at a downward cant to tapers 432, allowing the transmitted ambient light to be further bent and directed towards backlight panel 406.

The exterior ends of transmission conduits 418 are mated against pads 420 of backlight panel 406. It will be appreciated that in other embodiments a different number of conduits 418 may be provided. Alternatively, the conduits may be removed.

Upper opening 412 is located above opening 430 in housing 12A. As such, when device 10 is being held generally upright, lens 414 is also facing generally upwardly, thereby placing it in a favourable orientation to receive ambient light when device 10 is being held in a generally upright manner.

Lens 414 may be mounted at other locations in device 10, such as on the front, below display 14, on a side of device 10 or on the back of device 10. The specific location will have different light collecting characteristics, depending on the orientation of device 10. In other embodiments, several lens may be provided in different locations on device 10. As noted above, the general purpose of ambient light collector section 402 is to receive light through lens 414 and transmit it to backlight section 406.

As such, in other embodiments, different shapes, numbers and sizes for each part of each section may be provided, as long as the light section has the capability of collecting ambient light and transmitting it towards a backlight panel for a display.

Active light section 404 has two LEDs 408 mounted on platform 422. The electronic control circuit controlling LEDs 408 is not shown. LEDs 408 provide an active light source for backlight system 30.

In other embodiments, other technologies may be used for the active light source, such as lamps, and a different number of LEDs may be used.

When backlight system is assembled, LEDs 408 are mated to complementary cavities 424 in backlight panel 406 to make a generally snug fit within backlight panel 406. When LEDs 408 are activated by the control circuit, the light energy emitted therefrom enters backlight panel 406, which is then transmitted through LCD 14. The light path is generally shown by arrows 410.

Backlight panel 406 is a light spreading panel which is shaped to mate against the back face of display 14. It is shown in this embodiment as being generally oblong; however, other shapes may be implemented.

Light received from either ambient light collector section 402 through transmission pads 420 or LEDs 408 through cavities 422 is received into the interior of panel 406 then is dispersed within panel 406 and then transmitted to display 14 through top surface 426.

Panel 406 may have interior features to reflect light upward. Panel 406 may have a tapered block construction and may have approximately a trapezoidal form to more evenly distribute the light throughout top surface 426.

Display 14 is a preferably full-color device. More preferably, display 14 is a field sequential (FS) LCD--an LCD that reduces or obviates a need for colour filters. Alternatively, the LCD may contain colour filters in which case a white light source may be used. In FIGS. 4 and 5, the electronics controlling display 14 are not shown.

Different types of LCDs 14 have different light transmission/reflection properties. If the surface of LCD 14 is more reflective, e.g. via a reflective coating, it generally has good ambient light readability. If the surface of LCD 14 is more transmissive, then more light can pass through it (in both directions). This characteristic generally produces a darker image, requiring backlighting to improve readability.

Current systems incorporating backlighting for LCDs provide lighting of at least about 100 candella in light intensity. The amount of light provided by ambient light collector section 402 will vary on the intensity of the ambient light around device 10 and the positioning of device 10 relative to section 402 therein.

When mounted into device 10, display 14 is placed behind clear protective cover 428 and is mounted to mate with cavity 430 in housing 12A. Backlight panel 406 is positioned immediately underneath display 14, such that surface 426 is placed against or near the bottom surface 430 of display 14.

After all sections of backlight system 30 are assembled, housing 12B is mated to housing 12A to enclose display 14 and backlight system 30 within device 10. In other embodiments, LEDs 408 may be situated on a side or on the bottom of panel 406.

Save BlackBerry battery juice by using ambient light? Sounds like a winner to me.


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