SYSTEM FOR DISPLAYING INFORMATION TO A USER

Abstract

The invention relates to a system for displaying information, comprising: an emission device arranged to emit light so as to display information to a user, the emission device being adapted to emit the light in a pulsed manner so that the intensity of the light varies between a high value and a low value, a selective viewing device comprising a panel, the panel being adapted so that the user can view the light which is emitted by the emission device through that panel so as to visually perceive the information being displayed, the panel having a variable transparency which can be varied between a state of high transparency and a state of low transparency, the system being adapted to synchronize the emission device and the selective viewing device so that the states of the emission device emitting light at a high-intensity value and the states of the panel of the selective viewing device of high transparency overlap in time, the system further comprising a photoelectric conversion means arranged to convert ambient light into electric energy so as to feed the electric energy into the system.

Claims

1. System for displaying information, comprising: an emission device arranged to emit light so as to display information to a user, the emission device being adapted to emit the light in a pulsed manner so that the intensity of the light varies between a high value and a low value, a selective viewing device comprising a panel, the panel being adapted so that the user can view the light which is emitted by the emission device through that panel so as to visually perceive the information being displayed, the panel having a variable transparency which can be varied between a state of high transparency and a state of low transparency, the system being adapted to synchronize the emission device and the selective viewing device so that the states of the emission device emitting light at a high-intensity value and the states of the panel of the selective viewing device of high transparency overlap in time, the system further comprising a photoelectric conversion means arranged to convert ambient light into electric energy which is fed into the system.

2. System according to claim 1, further comprising an energy storage device (19) arranged to supply energy to drive the emission device, the energy produced by the photoelectric conversion means being used to store energy in the energy storage device.

3. System according to claim 2, wherein the energy storage device comprises at least a first and a second energy storage component, the system being arranged so that one of the first and the second energy storage components is charged whilst the respective other one supplies energy to the emission device, the system being arranged to swap the first and the second energy storage devices so that the respective energy storage component which previously was charged is now used to supply energy to the emission device whilst the respective other energy storage component is charged.

4. System according to one of the preceding claims, the photoelectric conversion means comprising a solar cell having an area exposed to ambient light which falls within the range of from 50 cm.sup.2 to 5000 cm.sup.2, preferably 200 to 2000 cm.sup.2, more preferably 400 to 1200 cm.sup.2.

5. System according to one of the preceding claims, the emission device having a duty cycle of less than or equal to 1/20, preferably less than or equal to 1/100 and even more preferably less than or equal to 1/250, wherein the panel of the selective viewing device is configured to operate at essentially the same duty cycle.

6. System according to one of the preceding claims, wherein the emission device is arranged so that an ambient contrast ratio of larger than 1, preferably larger than 4, more preferably larger than 10 is reached.

7. System according to one of the preceding claims, the emission device being arranged so that the intensity at the low value is less than 20%, preferably less than 10% of the intensity of the high level intensity, wherein even more preferably, no light is emitted when the emission device is set to emit light at the low value of the intensity.

8. System according to one of the preceding claims, the system being arranged so that the power consumption of the emission device is less than the power production by the photoelectric conversion means, wherein it is preferably less than 90%, more preferably less than 70% and even more preferably less than 50% of the power production by the photoelectric conversion means.

9. Portable computer system comprising the system according to one of the preceding claims.

10. Portable computer system according to claim 9, the portable computer comprising a screen having a front side and a rear side, the front side comprising the emission device as the display area, the rear side of the screen comprising the photoelectric conversion means, wherein the photoelectric conversion means preferably covers more than 70% and more preferably between 90% to 100% of the area of the rear side of the screen.

11. Portable computer system according to claim 9, wherein the photoelectric conversion means is provided so as to fold out from the portable computer.

12. Portable computer system according to claim 9, wherein the photoelectric conversion means is a component which is separate from the remaining components of the portable computer system and wherein it can be separated from those components without the use of a tool.

13. System according to one of claims 1 to 8, the emission device being a laser projector and/or a video projector.

14. System according to one of claims 1 to 8, the emission device and the photoelectric conversion means being incorporated into a tablet computer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG. 1 shows a prior art design taken from US 2013/0290743 A1.

[0062] FIG. 2 is a schematic drawing of a system according to the invention.

[0063] FIG. 3 shows the timing synchronization of the selective viewing device and of the emission device.

[0064] FIG. 4 shows a comparative view of a prior art laptop and of a laptop according to the present invention.

[0065] FIGS. 5 and 6 show view of the laptop according to the present invention.

[0066] FIG. 7 shows diagrams showing the power consumption of prior art devices and devices according to the present invention.

[0067] FIG. 8 shows the power consumption of laptop screens as a function of the brightness level.

[0068] FIG. 9 shows prior art light sources (bottom) and light sources used in the present invention (top).

DETAILED DESCRIPTION OF THE DRAWINGS

[0069] FIG. 1 is a drawing showing a prior art device. A solar panel 106 is connected to an electronic device (laptop) 102 and provides it with energy. Further, a power adapter 104 is connected to provide supplemental energy. However, given the power consumption by the laptop screen, it is to be expected that the solar panel 106 would need to be extremely large to power the electronic device 102.

[0070] FIG. 2 shows, schematically, a first embodiment of the present invention. A light source 12 is provided so as to illuminate an LCD matrix 13. Such a light source 12 could be the LED backlight of a computer screen. Connected to light source 12 is a driver 14b which is, in turn, connected to a function generator 15. This function generator 15 is connected to a second driver 14a which is, in turn, connected to shutter glasses 16. An observer 18 views the image which is produced by light source 12 emitting light 11′ which passed through LCD matrix 13. Of note, an ambient light source 10 (e.g. the sun) is also present and emits light 11.

[0071] The shutter glasses 16 are arranged to periodically vary between a high-transparency state and low-transparency state, as is shown in FIG. 3. Here, FIG. 3b) shows the intensity of the light source 12 varies in time. Synchronized with this intensity variation are the shutter glasses 16, as is shown in FIG. 3c), where the label “open” refers to the shutter glasses having a high transparency and where the label “closed” refers to the shutter glasses having a low transparency. In contrast to that, the light emitted by ambient light source 10 is constantly at the same level (cf. FIG. 3a)). By selectively opening the shutter glasses 16 for the light 11′ emitted by light source 12 only during those time periods when the shutter glasses 16 have a high transparency, this light 11′ is selectively perceived by observer 18. Since human eyes only generally perceive the average light intensity, light emitted by light source 12 is thus primarily observed, also since the light emitted by the light source is, during those time periods when light is emitted at a high intensity, at least as bright or even brighter than ambient light. Consequently, the perceived image contrast is increased and sufficient to enable satisfactory vision of a screen even in environments of high ambient intensity. We also note that the use of a common function generator 15 for first driver 14b and second driver 14a makes synchronizing the shutter glasses 16 and the light source 12 easier to implement. We also note that in FIG. 3c), the time periods are indicated as T.sub.on and T.sub.off which show the time periods when the shutter glasses have a high transparency (T.sub.on) and when they have a low transparency (T.sub.off). In this context, the duty cycle can be defined as T T.sub.on/(T.sub.on+T.sub.off). T.sub.on is 100ρs, and T.sub.off is 0.00990s, leading to a theoretical contrast enhancement of 100.

[0072] Connected to the light source 12 is a photoelectric conversion element (solar cell) 17. Light from the ambient light source 10 impinges on the photoelectric conversion element 17 and produces energy. The energy is supplied to an energy storage device 19 where energy can be stored. This energy is then used to drive the emission device 12 as well as being supplied to other components of the system.

[0073] FIG. 4 shows the results obtained using a prototype system. In the left view, one sees a normal view (i.e. without the inventive technology) of the laptop of the inventor in a home environment. Whilst the screen of the laptop can be seen, it is also noticeable that the contrast is not particularly high. Further, it is easily noticeable that the ambient light is much brighter. In the right-hand side of that image, the same environment is shown using the claimed invention. It is noticeable that the ambient light is dimmed to a significant degree and that also, the contrast on the computer screen is much higher. I.e., by selectively “eclipsing” the ambient light and selectively “gating” the laptop light, one achieves a higher contrast of the image to be seen on a laptop screen. In such cases, the screen could serve as a “slave” to the spectacles.

[0074] FIG. 5 shows a photograph of a laptop according to the present invention. As can be seen, the rear side of the laptop has been covered with a photovoltaic panel which has approximately the same size as that rear side.

[0075] This can also be seen from FIG. 6 where the front of the laptop is shown. Again, it can be confirmed that the area covered by the solar panel is approximately the same as the area of the screen of the laptop.

[0076] FIGS. 7a) and b) show schematically the power consumption of the laptop as a function of the brightness of sunlight when used in environments that are exposed to sunlight. Those drawings have been obtained based on the assumption that one will tune the brightness of the laptop screen so as to have an adequate contrast.

[0077] We shall consider FIG. 7a) first. The horizontal, dashed line denotes the intensity independent power consumption by components of the laptop. This could, for example, be the power consumption of the hard drive, CPU, Wi-Fi adapter, etc.

[0078] This power consumption is constant for an increasing brightness of the sunlight, since this power is consumed regardless of how much ambient light there is.

[0079] The inclined line with the reference numeral I denotes the solar power production. It is clear that this production increases approximately linearly with the brightness of the sunlight and that for no sunlight, no power is produced.

[0080] The line III shows the power consumption of the light source of this screen as a function of the intensity of the sunlight. It is understood that the brighter the sunlight, the brighter the screen has to be so as to provide an acceptable contrast. Also this power consumption is roughly proportional to the brightness of the sunlight. Finally, line II shows the net power consumption of the laptop as a whole, where the energy produced by the solar cell is taken into account, so that the remaining net energy requirement is shown. As can be seen from this schematic drawing, the power produced by the solar panel is significantly less than the power consumed and described by line III, such that the resulting net power consumption II remains positive and increases with increasing brightness.

[0081] FIG. 7b) shows the power consumption of a laptop according to the present invention. Here, the same notation was used as is also used in FIG. 7a), with an additional “′” to denote the differences. Again, the energy production by the solar cells increases approximately linearly with the brightness of the sunlight, as identified by the line I′ (which should be identical to the line I in FIG. 7a)). However, the energy consumption by the screen is significantly reduced since its light source only needs to be operated a fraction of the time (cf. line III′). With the power consumption by the other components being approximately constant, as indicated by the dashed line, the net power consumption (line II′) is reduced and shows a negative slope. In particular, it becomes negative starting from a point A. Accordingly, with a laptop according to the present invention, energy can even be produced whilst operating it outdoors.

[0082] FIG. 8 shows schematically the power consumption of the screen increases with the brightness level.

[0083] The operation of the prototype shown in FIGS. 5 and 6 is now described. The prototype is a standard laptop PC where the screen has been modified and fitted with optoelectronic components to only emit light from the screen at a certain repeat rate. Goggles which have a transparency which is synchronized with the screen were worn by a user. A repeat rate of 250 Hz was used for the screen to avoid noticeable flickering.

[0084] It is then the case that electric power is consumed by the light sources only during the durations of light emissions for which we used a repetition rate of e.g. 250 Hz, together with a duty cycle of 1/40, meaning an on-time of 0.1 ms. With an adequate light source that is e.g. 20× brighter than usual, peak power consumption will also be 20× than before. However, because the duty cycle is 1/40, the time-average energy consumption of the screen will be reduced by half. In other words, the screen contrast is perceived as 20× higher than before, at a reduced energy consumption compared to the case of operating a laptop conventionally. Alternatively, with peak intensities that are 5 times increased compared to normal usage, the battery consumption of the screen would even be reduced 8 fold.

[0085] It was tested whether such a laptop can be used in sunlight. The contrast was found to be satisfactory, as can also be seen from FIG. 4, which shows photos obtained using a prototype which does not have a solar panel fitted. Further, the user can now benefit from intense ambient sun light. In particular, the light intensities in the surrounding are available throughout the entire duty cycle and may be used to charge the battery laptop, such that a laptop sized solar panel with dimension of e.g. 20 cm×30 cm can even be sufficient to (over-)compensate for the entire power consumption of the screen's light source.

[0086] This was also confirmed from the prototype which was built. When using that prototype, the inventor found a solar panel of approximately these dimensions (compare FIG. 7) to be sufficient to produce more electric power than consumed by the light source of the laptop. In particular, he connected this solar panel to the batteries driving

the laptop's screen light via a maximum-power-point-tracking (MPPT) electric-power-converter to charge batteries while operating the screen. This way, he found 3.4±0.5 Watts of electric power sufficient to operate light sources and comfortably view the screen in the very same environment in which a solar panel positioned on the back of the laptop produced 4.8-5.2 Watts of solar power (all measured with in-line power meters as seen in FIG. 6). This proof of concept shows that, despite a sub-optimal design, and despite using a rather old and somewhat inefficient computer, solar cells on the backside of the screen can be used to compensate for the energy consumption of the screens light source, and even provide some extra energy beyond. It was thus shown that the solar panel produces enough energy to drive the screen whilst also having approx. 1 W of energy surplus. This would be enough to drive modern, energy efficient electronics like a computer and thus shows that the prototype could be extended to be a stand-alone laptop.

[0087] This shows that suddenly, battery life of laptop complemented by small solar cells may increase when operating the device in bright, compared to dimmer environments. This means that taking a laptop from a position in the shadow to a position exposed by direct sunlight may extend battery lifetime without compromising on image contrast.

[0088] The inventor further considered whether this would allow one to watch a movie on a bright beach on a laptop whilst entirely relying on solar energy to drive the laptop.

[0089] To start with, the following numbers should be suitable to put the elevated energy consumption of a laptop screen in a bright environment into proportion to the rest of its components. A usual laptop (i.e. Macbook air 2018) is reported to have a battery capacity of 50.3 Wh, with which, depending on usage, it runs up to 12 hours according to Apple. This means that the average power consumption during this time is around 4.2 Watts. At normal (office) usage 1-2 Watts of this of this will be used by the screen, and the highest fraction of this for its illumination.

[0090] Furthermore, the Lenovo Thinkpad model 410s had a 4 Watt LED source built-in. Likewise, 3.5 Watts of electric power consumption were reported for older generation laptops. This means that normal laptops use a significant fraction, if not most of their power consumption, to operate the light source within the screen, particularly when attempting to generate good contrast via intensity adjustment in bright environments. In particular, when transitioning from an indoor office, which in Germany typically has a recommended luminosity of 500 lx, outdoors might necessitate to increase screen brightness 10-fold or more, in order to achieve a given desired contrast. This however would result in energy costs that cannot be compensated for by a solar panel. As a reference, a panel with the size of 32×22 cm.sup.2 will produce up to 10 Watts of electric power (referenced for a maximum sun light intensity of 1000 Watts/m.sup.2). When testing it attached to a laptop screen according to the state of the art, the obtained 5 Watts of electric energy were far away from producing an appealing ambient contrast ratio under normal viewing conditions.

[0091] Complemented by the technology of only emitting pulsed light, the power requirement of the screen's light source drops significantly. As an example, that technology may be used to obtain a perceived brightness (contrast) increase of 10 fold, while decreasing the energy consumption of the screen even 4 fold compared to standard (indoors) use.

[0092] This power balance is valid for a particular example but its implications can be generally understood when considering the net power balance of the laptop operating outdoor. The diagrams in FIG. 7 compare the outdoor uses of a conventional solar laptop outdoor with the solar eclipse laptop. As one can see, with a duty cycle that reduces screen energy consumption by 1/40×, meaning down to 2.5%, the net power balance favorably increases with increasing sun light intensity, even for a fixed ambient contrast ratio. This means that with a solar cell comparable to the dimension of the laptop, batteries may be charged while using the laptop.

[0093] Would this allow to charge a laptop while watching movies at the beach? This depends on how much energy the laptop needs to operate other components. We have already explained above that it was managed to obtain a decent ambient contrast ratio with the prototype. Given that this prototype is operating far from optimally (as an example an important foil was removed that back-reflects non-LCD-transmitted light and thereby reduces energy consumptions of typically >25%), there is much room for improvements, and clearly energy consumption could be reduced a significant fraction, such that very reliably more than 1 Watt of electric power remains available to power other components. As can be learnt from the iPhone 7 website, which allows to watch up to 13 hours of video with a 11.1 Wh battery, 1 Watt of electric power is more than enough to operate hardware to send a high resolution video signal to a screen. In conclusion the here presented system enables to charge laptops via screen-sized solar panels while operating them.