Ambient light blocker

An ambient light blocker that may include an array of spatial filters of microscopic width and microscopic length; and transparent elements that are surrounded by the spatial filters of the array and are of microscopic width.

BACKGROUND

Today digital and analog displays are very popular. They are used in mobile phones, smart phones, wearable devices, tablets, computers, Display of digital camera, TV, big outdoor screens, car display, etc. When a digital or analog display is used outdoors on a sunny day, it is almost impossible to see what is displayed on the screen. This is due to the glare of the sun and the ambient light and the ambient image that is reflected from the interfaces of its cover glass and mixes up with the displayed image thus, significantly lowers the contrast of the display below usability. We call it blindness of the display. As an example, inFIG. 1andFIG. 2we depict two typical displays of a mobile phone in outdoor on a sunny day and in indoor scenarios respectively.

This phenomenon occurs especially in mobile devices where the ambient light condition changes significantly while their display brightness is limited, such as mobile phones, tablets, wearable device, displays in cars, navigation displays, display of digital camera, big outdoor screens, etc., that are used in indoor and outdoor scenarios, day, and night.

In order to reduce the blindness effect of the display some people block the sun with their hand in order to improve the visibility of the display, but with little success. Popular Anti-Glare, matte finish screen protectors, scatter the ambient light but with little success and at the cost of the resolution of the display.

The blindness effect is due to the high intensity of the reflected and scattered ambient light from the mobile phone display compared to the intensity of the displayed signal.

SUMMARY

There may be provided an ambient light blocker that may include an array of spatial filters of microscopic width and microscopic length; and transparent elements that are surrounded by the spatial filters of the array and are of microscopic width.

The ambient light blocker may include a base and wherein the spatial filters are substantially normal to the base.

The base is formed from lower surfaces of the spatial filters and lower surfaces of the transparent elements.

The distance between spatial filters that do not contact each other and surround a certain transparent element may exceed a width of the certain transparent element.

A distance between spatial filters that contact each other and surround a certain transparent element may exceed, by at least a factor of four, a width of the certain transparent element. Any other factor may be provided.

The array of spatial filters may include non-transparent spatial filters.

The spatial filters may have an elongated cross section.

The ratio between a height of a spatial filter and a width of the spatial filter may exceed ten. Any other ratio may be provided.

The ratio between a height of a spatial filter and a width of the spatial filter may exceed five.

The spatial filters may have a rectangular cross section.

The array of spatial filters may include spatial filters that may include dark pigments.

The array of spatial filters may include spatial filters of controllable transparency.

The ambient light blocker may include a controller for controlling a transparency of the spatial filters.

The ambient light blocker may include a controller for independently controlling a transparency of different sub-arrays of the array of the spatial filters.

The ambient light blocker may include a control input; wherein the array of spatial filters may include spatial filters of controllable transparency; wherein the control input may be configured to receive signals for controlling the transparency of the spatial filters.

The ambient light blocker may include a controller and an ambient light sensor, wherein the ambient light sensor may be configured to sense ambient light and wherein the controller may be configured to control a transparency of the spatial filters based on the sensed ambient light.

The ambient light blocker may include a controller and an ambient light sensor, wherein the ambient light sensor may be configured to sense ambient light and wherein the controller may be configured to control a display intensity of a display of a device that is coupled to the ambient light blocker based on the sensed ambient light.

The array of spatial filters may include static spatial filters.

The ambient light blocker may include a controller and wherein the array of spatial filters may include movable spatial filters; wherein the controller may be configured to control a movement of the spatial filters.

The ambient light blocker may include a control input and wherein the array of spatial filters may include movable spatial filters; wherein the control input may be configured to receive signals for controlling a movement of the spatial filters.

The ambient light blocker may include an anti-reflecting coating layer.

The anti-reflecting coating layer may precede the array of spatial filters.

The anti-reflecting coating layer may be substantially normal to the array of spatial filters.

The spatial filters may be coated with anti-reflecting material.

The ambient light blocker may be integrated in a display of a device.

There may be provided a device that may include a display and an ambient light blocker, wherein the ambient light blocker may include an array of spatial filters of microscopic width and microscopic length; and transparent elements that are surrounded by the spatial filters of the array and are of microscopic width.

The ambient light blocker may be glued to the display.

The light blocker may be integrated with the display.

The device may include a controller for independently controlling a transparency of different sub-arrays of the array of the spatial filters.

The device may include a control input; wherein the array of spatial filters may include spatial filters of controllable transparency; wherein the control input may be configured to receive signals for controlling the transparency of the spatial filters.

The device may include a controller and an ambient light sensor, wherein the ambient light sensor may be configured to sense ambient light and wherein the controller may be configured to control a transparency of the spatial filters based on the sensed ambient light.

The device may include a controller and an ambient light sensor, wherein the ambient light sensor may be configured to sense ambient light and wherein the controller may be configured to control a display intensity of a display of a device that is coupled to the ambient light blocker based on the sensed ambient light.

The array of spatial filters may include static spatial filters.

The device may include a controller and wherein the array of spatial filters may include movable spatial filters; wherein the controller may be configured to control a movement of the spatial filters.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Any reference to a device or an ambient light blocker should be applied, mutatis mutandis to a method that is executed by the device or the ambient light blocker.

Any reference to method should be applied, mutatis mutandis to a device or an ambient light blocker that is configured to execute the method.

The terms “including”, “comprising”, “having”, “consisting” and “consisting essentially of” are used in an interchangeable manner. For example—any method may include at least the steps included in the figures and/or in the specification, only the steps included in the figures and/or the specification. The same applies to the device and the ambient light blocker.

The intensity of the ambient light in indoor is around 1,000 lux and the displayed image is clear and visible.

However, the ambient light intensity in outdoor, on a sunny day, is around 100,000 lux while the typical display brightness is in the range of 300-1000 cd/m{circumflex over ( )}2.

Hence, in order be able to see the display clearly, it is necessary to reduce the intensity and contrast of the reflected ambient light and by a factor of 1-2 orders of magnitude.

FIG. 3illustrates the impact of the ambient light105with intensity Is on the display panel101.

Let us denote Isr as the intensity of the reflection ambient light110from the display panel.
Isr=Is*R

Where R is the reflection coefficient of the display that accumulates the reflection from all its optical interfaces.

Id is the intensity of the image115that is presented on the display101.

On a sunny day Isr>>Id, hence the Id signal is almost unnoticeable by the user eye102, which effectively blocks the user eye from seeing the displayed image.

There may be provided a method and apparatus that reduces the blindness effect of the display.

To reduce the reflected ambient light intensity and ambient image contrast on sunny days there may be provided an ambient light blocker that may include an array of spatial filters, which filters the ambient light coming from directions that are not perpendicular or close to be perpendicular to the display.

The ambient light blocker may also include an ARC (Anti-Reflective Coating) that may further decrease the reduced ambient light that is perpendicular to the display.

The ambient light blocker may also include an index matching glue between the display and the cover that decreases the reflection from that interface.

The spatial filters may be arranged in any manner—an ordered grid, a non-ordered grid, and the like.

The spatial filters of the array surround transparent elements. The transparent elements may be of any shape—circle, triangle, rectangle, polygon, curved and the like.

An example for such spatial filter, there may be provided a specific layer that includes an array of rectangular filters (micro-elements), as illustrated onFIGS. 4 and 5.

It should be noted that any shape of transparent elements and/or spatial filters that can fully cover the display (or at least cover a region of interest of the display) area can be considered, such as an array of triangles, rectangles, hexagonal etc. The region of interest may be defined by a manufacturer of the ambient light blocker, by the manufacturer of the display, by a user, and the like.

FIG. 4shows the rectangular case, wherein each transparent element is of size d1*d2and height h.

This transparent material allows the rays that are generated in the display to penetrate via the material toward the eye of the user which enables him to see the content that is displayed.

The spatial filters are denoted410and are non-transparent and are used as “black” (or other non-transparent) borders between the transparent elements, that absorb the rays that are coming from the ambient light in angle>Alpha/2 (seeFIG. 5) relative to the vertical to the display.

Alpha may be defined by the relationship between a height h of the spatial filters and the dimensions (width of length respectively) of the transparent part.

Typical black material can be a material that contains black pigments. Non-limiting examples of materials may include Polycarbonate, PMMA, etc.

FIG. 5is a one-dimensional cross section of one of the rows ofFIG. 4.

It should be noted thatFIG. 4presents an upper view of the array of spatial filters and transparent elements but that a combination of a transparent element and spatial filters that surround it may be a cubic element. The planes that are perpendicular to the display consist of “black” material410and the other material is a transparent polymer or air405.

The size of each cubic element in the basis is (d1+W)*(d2+W), the height is h and the thickness of the black border is W. Typical values of d1, d2, W and h may be on the scale of micrometers. Non-limiting example of d1, d2, W and h are . . . d1=d2=40 μm, h=100 μm and W=15 μm. which are below the resolution of human eye. The ratios of d1, d2and h have a significant impact on filtering of the ambient light that is not perpendicular to the display, on the other hand if h is too high or d1and d2are too small it might narrow the angle of view of the display.

FIG. 5illustrates the ambient light blocking process, especially the ray502and503as an example.

Ray502has an intensity I2and first impacts spatial filter410to provide first reflected ray502′ that is attenuated significantly by the reflection of the wall by the amount of Rw. Rw may range between . . . 0.01 and 0.1

The intensity of first reflected ray502′ is Rw*I2.

The first reflected ray502′ is reflected towards the other wall of the spatial filter—and is reflected from the wall (after being attenuated by Rw) to provide second reflected ray502″.

The intensity of second reflected ray502″ is Rw*Rw*I2.

The second reflected ray502″ is reflected from the display (after being attenuated by Rb) to provide third reflected ray502′″.

The intensity of third reflected ray502′″ is Rb*Rw*Rw*I2.

The total attenuation of ray502is Rb*Rw*Rw and represents a significant reduction in intensity compared to ray502. As both Rb and Rw are <<1 thus, the reflected ray502′″ has a residual intensity Rb*Rw{circumflex over ( )}2*I2that is much smaller than the original intensity of I2.

Ray503presents a different angle of impact.

Ray503has intensity I3and first impacts display101to provide first reflected ray503′ that is attenuated significantly by Rb. Rb may range between . . . 0.02 and 0.05.

The intensity of first reflected ray503′ is Rb*I3.

The first reflected ray503′ is reflected towards the black wall of the spatial filter—and is reflected from the wall (after being attenuated by Rw) to provide second reflected ray503″.

The intensity of second reflected ray503″ is Rb*Rw*I3.

I3*Rb*Rw is significantly attenuated compared to I3.

At impact angles such as in504and505the spatial filters have no affect—and the reflected rays are attenuated by the display by Rb.

Ray410(and rays that further deviate from the normal501to the display) are blocked.

It is clear that as d1and d2are reduced and/or h becomes higher it will increase the filtered ambient light effect. However, decreasing of d depends on W.

W is the width of the spatial filter410, should obey W/di (i=1,2) is much smaller than one for both d1and d2, to ensure that the intensity of light coming from the display is almost not attenuated.

The attenuation of the intensity of the display light, is the ratio between the transparent window d1*d2to the filter dimension (d1+W)*(d2+W) hence; d1*d2/[(d1+W)*(d2+W)]=1/[1+W/d2+W/d1+(W/d1)*(W/d2)]≃1 for W/di<<1, this ensures that the intensity of the light coming from device501is not significantly attenuated, and the display appears to the user eye as through a transparent layer.

To further reduce the intensity of the ambient light, especially the light that is perpendicular to the display, the ambient light blocker may include an upper layer (denoted605ofFIG. 6) that is an Anti-Reflective Coating (ARC) layer, which enables to attenuate a ray that impinges at an angle that is smaller than Alpha/2 in relation to a normal to the display and is back reflected to the eye of the viewer.FIG. 6also illustrates a glue layer610that is also transparent.

The glue layer may be replaced by any other base layer (such as base layer611ofFIG. 7) that is transparent and provides support to spatial filters and/or may provide an attachment surface for attachment to display101.

The reflectance of the display itself (Rb) may be about 4% and may be further reduced by an order of magnitude by the use of an index matching glue/gel610. It should be noted that one can choose not to add at least one of layers605and610.

The use of an ARC layer alone without the array of spatial filters may not be sufficient to suppress the glare of the ambient light and the ambient image on a sunny day, nor is the above mentioned, matte finish anti-glare.

FIG. 8illustrates the ambient light blocker that has a glue layer610, transparent elements405and spatial filters410but does not have the anti-reflective layer605.

The ambient light blocker may be integrated with the display.

The ambient light blocker may be removable attached or detachably attached to the display.

The ambient light blocker may include a separate base (see base611ofFIG. 7). Alternatively—the base of the ambient light blocker may be formed by the bases (lower part) of the spatial filters and/or of the transparent elements.

The ambient light blocker may be an add-on.

Referring to the array of spatial filter presented inFIG. 5—a reduction of the dimension of d1and d2and/or an increase of h expand the angular range of blocked ambient light rays.

The ambient light blocker may also prevent a person that is located at the side of the user of the device from viewing the display, which keeps the user privacy. However, in cases where it is important that user shares its displayed content with his friend, the spatial filter may become transparent (when the spatial filters have a controlled transparency). The transparency may be controlled by control signals such as electrical signals.

Spatial filters of controllable transparency may be liquid crystal displays. This can be controlled by the user, namely an application in the device can switch on or off the border per user request.

In cases where the user would like that in normal light condition the layer will be fully transparent, then one can use a sensor (such as a light meter) in a device that includes the display (such as a phone) to implement an ALC (Automatic Light Control) that may automatically switch off the black border and the layer become fully transparent in good light condition and if the intensity of the light is very high it automatically will switch on the border to become black borders and will filter the ambient light.

FIG. 10illustrates a controller420that may control a parameter of the ambient light blocker by sending control signals via control inputs422. The parameter may be a transparency of the spatial filters, a position (angular deviation) of the spatial filters and the like.

The control signals may affect all the spatial filters of the array, only some of the spatial filters of the array and even only signal one spatial filter. Any combination of spatial filters may be independently controlled (for example by using different control signals) with any other combination of spatial filters. For example—different rows and/or different columns of spatial filters may be controlled independently.

FIG. 11differs fromFIG. 10by illustrating a sensor430that provides detection signals to the controller420. Controller420may control one or more spatial filters based on the detection signals. The detection signals from sensor430may reflect ambient conditions (such as intensity of ambient radiation, direction of ambient radiation, time, location, and the like. For example—the location and time may indicate whether the device is outdoors, whether the sun has shined, whether it is night time and the like.

The sensor430and/or the controller420may belong to the ambient light blocker, may belong to a kit that includes the ambient light blocker, may be included in a device that also includes the display, may be included in the display, and the like.

There may be more than one sensor of the same type and/or of different types.

FIG. 12illustrates multiple sensors430that may be located above, below or integrated with the ambient light blocker. These sensors may be ambient light sensors that measure light intensity at different locations of the ambient light blocker. The sensor may be coupled to controller420that in turn may control the ambient light blocker based on the readings of the sensors.

There may be one or more controllers for controlling one or more parts of the ambient light blocker and/or for controlling the intensity of illumination of the display.

FIG. 13illustrates a device such as a mobile phone or any computerized device—the device includes display110, the ambient light blocker400and various components111such as controller420and sensor430. Any other component required for the functionality of the device may be providing—for example microphone, speaker, processor, communication module, and the like.

FIG. 14illustrates the ambient light blocker as including movable spatial filters410. The spatial filters may be moved (for example—by rotation—thereby changing their orientation—407) by moving elements (for example microscopic motors406).

It should be noted that due the fact that the spatial filters reduce the ambient light, in some cases we can decrease the display intensity and still have good visibility of the display. This fact can be used to reduce the power dissipation of the display and the amount of the heat up, which has a significant impact on the battery life of the device.

In most of the mobile phone there is a light sensor in the front of the display to measure the light intensity. With this information, the display can use auto brightness algorithm that change the display brightness according to the ambient light. If our filters cover also the light sensor, the filters will reduce the ambient light that the sensor detects and hence will reduce automatically the brightness of the display which will reduce the power consumption of the display.

There may be provided a method for operating an ambient light blocker. The ambient light blocker includes an array of spatial filters of microscopic width and microscopic length, and transparent elements such as polycarbonate or air that are surrounded by the spatial filters of the array and are of microscopic width. The spatial filters have at least one controllable parameter such as transparency and location. The method may include controlling at least one parameter of the spatial filters. The method may include receiving sensor information and/or generating sensor information and/or commands from a user or other entity—and controlling the spatial filters accordingly. For example—changing the transparency of one or more spatial filter based on a request of user, based on the intensity of ambient light, based on content displayed on the display, and the like.

Any system, apparatus or device referred to this patent application includes at least one hardware component.