Handheld electronic device

1. A portable electronic device comprising:

a housing;

a front cover coupled to the housing and defining a front side of the portable electronic device;

a display stack below the front cover and comprising a plurality of display layers configured to produce a graphical output in a display region of the display stack, the graphical output visible through the front cover; and

a light sensor module positioned at least partially within the housing and coupled to the display stack in the display region, the light sensor module configured to:

receive ambient light passing through the front cover and through the plurality of display layers; and

while a blanking interval is positioned over the light sensor module, produce an output corresponding to the received ambient light, the portable electronic device configured to determine an ambient light value based at least in part on the output from the light sensor module.

2. The portable electronic device of claim 1 , wherein:

the portable electronic device further comprises a camera positioned in a front-facing sensor region of the front side of the portable electronic device and configured to capture images through the front cover; and

the light sensor module is proximate the front-facing sensor region.

3. The portable electronic device of claim 1 , wherein the ambient light value is a color temperature of the ambient light.

4. The portable electronic device of claim 3 , wherein the portable electronic device is further configured to change a display parameter of the display stack based at least in part on the ambient light value.

5. The portable electronic device of claim 1 , wherein the blanking interval is a vertical blanking interval.

6. The portable electronic device of claim 1 , wherein:

at least one of the plurality of display layers comprises electrodes;

the electrodes are arranged in a first pattern in an area above the light sensor module; and

the electrodes are arranged in a second pattern different from the first pattern in an area remote from the light sensor module.

7. The portable electronic device of claim 6 , wherein the first pattern corresponds to a first subset of the electrodes being layered on top of a second subset of the electrodes.

8. A mobile phone comprising:

a housing;

a transparent cover coupled to the housing;

a display stack at least partially within the housing and positioned below the transparent cover, the display stack comprising:

a plurality of display layers configured to produce a graphical output visible through the transparent cover; and

an opaque masking layer positioned below the plurality of display layers and defining a hole; and

a light sensor module coupled to the display stack and configured to:

receive ambient light that passes through the transparent cover, the plurality of display layers, and the hole in the opaque masking layer; and

produce an output corresponding to the received ambient light, the mobile phone configured to determine a color temperature of the ambient light based at least in part on the output from the light sensor module.

9. The mobile phone of claim 8 , wherein an area of the hole in the opaque masking layer is smaller than an area of a light sensing element of the light sensor module.

10. The mobile phone of claim 8 , wherein:

the plurality of display layers define a plurality of pixels configured to be selectively illuminated to produce the graphical output, the plurality of pixels including:

a first subset of pixels positioned over the hole in the opaque masking layer; and

a second subset of pixels positioned remote from the hole in the opaque masking layer; and

the color temperature is determined based on ambient light that is received while the first subset of pixels are not illuminated.

11. The mobile phone of claim 8 , wherein:

the display stack comprises electrodes extending over an active area of the display stack;

the hole in the opaque masking layer is positioned in the active area of the display stack;

a pair of the electrodes is positioned in an overlapping pattern in an area over the hole in the opaque masking layer; and

the pair of the electrodes is positioned in a non-overlapping pattern in an area remote from the hole in the opaque masking layer.

12. The mobile phone of claim 8 , wherein the mobile phone is further configured to change a display parameter of the display stack based at least in part on the color temperature.

13. The mobile phone of claim 12 , wherein the display parameter is a color temperature of the graphical output.

14. The mobile phone of claim 8 , wherein the light sensor module further comprises:

a light sensing element; and

a light diffuser positioned below the opaque masking layer and above the light sensing element.

15. A method of determining an ambient light measurement with a portable electronic device, comprising:

displaying a graphical output with a display stack positioned below a front cover of the portable electronic device, the graphical output visible through the front cover; and

determining an ambient light value of ambient light external to the portable electronic device, comprising:

sensing light with a light sensor module positioned below the display stack, the sensing performed at a time when the graphical output is visible and a portion of the display stack covering the light sensor module is not emitting light;

producing an output corresponding to the sensed light; and

determining the ambient light value based at least in part on the output from the light sensor module.

16. The method of claim 15 , wherein:

the display stack comprises an opaque masking layer defining a hole;

the light sensor module is positioned below the opaque masking layer and senses the light through the hole in the opaque masking layer; and

the output corresponding to the sensed light includes:

a first component resulting from the ambient light received through the front cover and through the portion of the display stack covering the hole in the opaque masking layer; and

a second component resulting from light emitted by a portion of the display stack not covering the hole in the opaque masking layer.

17. The method of claim 16 , wherein the operation of determining the ambient light value comprises at least partially subtracting the second component from the output.

18. The method of claim 17 , wherein the second component corresponds to a color emitted by the portion of the display stack not covering the hole in the opaque masking layer.

19. The method of claim 17 , wherein the second component corresponds to a brightness of the portion of the display stack not covering the hole in the opaque masking layer.

20. The method of claim 15 , wherein:

the display stack defines a plurality of pixels configured to be selectively illuminated to produce the graphical output;

while the graphical output is displayed, a blanking interval defined by a region of non-illuminated pixels moves along an active area of the display stack; and

the ambient light value is determined based on the light that is sensed while the blanking interval is above the light sensor module.