Device Including Multi-Function Circuitry Having Optical Detectors and Method of Flip-Chip Assembly Therefor

• US 20110248961A1
• Filed: 11/17/2010
• Published: 10/13/2011
• Est. Priority Date: 04/13/2010
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Holcombe, Wayne T., Svajda, Miroslav, Gerber, Steve
• Granted Patent: US 9,651,421 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 3/7803 Means for monitoring or calibrating
• CPC Class Codes: G01S 3/7835 using coding masks
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4913 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G01S 7/4972 Alignment of sensor
• CPC Class Codes: G01V 8/20 using multiple transmitters or receivers

Abstract

A device includes a substrate is substantially transparent and includes a contact surface and an interface surface. The interface surface includes a plurality of electrical contacts. The device further includes a semiconductor die, which includes a plurality of connections, a first photo detector and a second photo detector. Each of the plurality of connections includes a connection bump formed thereon to couple to the plurality of electrical contacts of the interface surface of the substrate. The plurality of connections positioned relative to the first and second photo detectors to alter a directional response of at least one photo detector of the plurality of photo detectors.

Claims

1. An apparatus comprising:

a substrate comprising a contact surface and an interface surface, the interface surface including a plurality of electrical contacts, the substrate being substantially transparent; and

a semiconductor die comprising a plurality of connections and a plurality of photo detectors, each of the plurality of connections having one of a plurality of connection bumps formed thereon to couple to the plurality of electrical contacts of the interface surface of the substrate, the plurality of connections positioned relative to the plurality of photo detectors to alter a directional response of at least one photo detector of the plurality of photo detectors.

2. The apparatus of claim 1, further comprising:

at least one light emitting diode (LED) configured to emit light over the contact surface of the substrate; and

wherein the plurality of photo detectors generate electrical signals in response to receiving incident light through the substrate, the incident light including reflected light from an object positioned adjacent to the contact surface the electrical signals indicating a proximity of the object.

3. The apparatus of claim 1, wherein the plurality of connections are positioned relative to the plurality of photo detectors such that the plurality of connection bumps provide at least partial optical isolation of one or more photo detectors in the plurality of photo detectors;

and

wherein the plurality of connection bumps cooperate with other optical barriers to enhance spatial dependence of incident light received by at least one of the plurality of photo detectors.

4. The device of claim 1, wherein the semiconductor die comprises:

one or more analog-to-digital converters coupled to the plurality of photo detectors and configured to receive the electrical signals from one or more of the plurality of photo detectors and to convert the electrical signals into digital signals proportional to the incident light, the digital signals indicating a proximity of the object; and

a control circuit coupled to the analog-to-digital converter and configured to detect motion of an object in response to changes in the proximity.

5. The device of claim 4, wherein the substrate comprises:

a plurality of capacitive electrodes coupled to the plurality of electrical contacts; and

wherein the semiconductor die comprises;

capacitive driver interface coupled to a first set of connections of the plurality of connections and configured to apply signals to selected electrodes of the plurality of capacitive electrodes;

a multiplexer including a plurality of inputs coupled to a second set of connections of the plurality of connections, a control input coupled to the controller, and an output; and

an analog-to-digital converter including an input coupled to the output of the multiplexer and including an output coupled to the controller; and

wherein the control circuit is configured to detect changes in capacitances via the plurality of capacitive electrodes.

6. The device of claim 4, wherein the control circuit is configured to determine proximity of an object based on the directional response of at least one of the plurality of photo detectors and to determine user input based on changes in the proximity and based on the changes in the capacitances.

7. The device of claim 6, wherein the control circuit is configured to utilize the changes the proximity to resolve ambiguities in the changes in the capacitances.

8. The device of claim 1, further comprising a transparent underfill disposed between the plurality of connection bumps of the semiconductor die and between portions of the semiconductor die and the interface surface of the substrate.

9. A computing device comprising:

a touch-screen substrate including an interface surface having an interconnect layer, the touch-screen substrate including a substantially transparent portion;

an intesemiconductor die including an active surface having a plurality of connections, a first photo detector and a second photo detector, each of the plurality of connections including a connection bump of a plurality of connection bumps formed thereon, the semiconductor die mounted to the interconnect layer to electrically and physically couple the integrated circuit die to the touch-screen substrate; and

wherein the plurality of connection bumps alter directional characteristics of the first photo detector and the second photo detector, such that the first photo detector has a first directional response that is different with respect to a second directional response of the second photo detector.

10. The computing device of claim 9, further comprising an encapsulant deposited over a second surface of the semiconductor die to seal the semiconductor die to the interface surface of the touch-screen substrate.

11. The computing device of claim 10, further comprising a transparent underfill between the plurality of connection bumps and between the semiconductor die and the touch-screen substrate.

12. The computing device of claim 9, wherein the semiconductor die comprises:

a control circuit configured to determine a proximity of an object based in part on a difference between first electrical signals corresponding to the first directional response and second electrical signals corresponding to the second directional response; and

wherein the control circuit is configured to generate a signal to control a backlight intensity in response to determining the proximity.

13. The computing device of claim 9, wherein the first photo detector and the second photo detector receive incident light;

and

wherein the semiconductor die comprises;

a controller configured to detect proximity of an object relative to the touch-screen substrate based in part on differences between first electrical signals proportional to first incident light received by the first photo detector and the second electrical signals proportional to second incident light received by the second photo detector

14. The computing device of claim 13, wherein the controller is configured to detect motion of the object proximate to the touch-screen substrate based on changes over time in at least one of the first incident light and the second incident light.

15. The computing device of claim 14, further comprising a light-emitting diode configured to emit infrared light above the touch-screen substrate;

wherein the incident light includes reflected light; and

wherein a second at least some of the plurality of connection bumps cooperate to provide spatial dependence between the first incident light and the second incident light.

16. The computing device of claim 9, wherein the plurality of connections are arranged in an array having rows and columns;

and

wherein a spacing between adjacent connections within a row and within a column of the array is substantially uniform.

17. A method comprising:

calibrating a plurality of photo detectors of a multi-function integrated circuit to determine ambient light conditions, the multi-function integrated circuit mounted to an interconnect layer of a substantially transparent portion of a touch-screen substrate, the multi-function integrated circuit including the plurality of photo detectors and a plurality of connections, each of the plurality of connections having a connection bump of a plurality of connection bumps formed thereon, the plurality of connections positioned such that the plurality of connection bumps cooperate to alter a directional response of a first photo detector of the plurality of photo detectors relative to a second photo detector of the plurality of photo detectors; and

determining a proximity of an object relative to the touch-screen substrate based on electrical signals produced by the plurality of photo detectors and based on calibrating the plurality of photo detectors, the electrical signals proportional to the light received by the plurality of photo detectors.

18. The method of claim 17, wherein calibrating the plurality of photo detectors comprises:

turning off a light-emitting diode;

measuring ambient light using at least one of the plurality of photo detectors;

turning on the light-emitting diode; and

measuring light using the at least one of the plurality of photo detectors to determine the proximity of the object.

19. The method of claim 17, further comprising:

capturing a first ambient light measurement using at least one of the plurality of photo detectors;

adjusting a backlight intensity by a predetermined amount;

capturing a second ambient light measurement using the plurality of photo detectors; and

determining the ambient light conditions by calculating a contribution of the backlight intensity to the first ambient light measurement and the second ambient light measurement.

20. The method of claim 19, further comprising adjusting a backlight intensity in response to determining the ambient light conditions.

21. The method of claim 17, further comprising:

determining ratios of reflectances between pairs of the plurality of photo detectors;

determining changes in the ratios of reflectances over time; and

detecting motion of the object relative to the touch-screen substrate based on changes in the electrical signals over time.

22. The method of claim 17, wherein determining the proximity comprises:

controlling at least one light source to direct light including at least one infrared frequency above a surface of the touch-screen substrate; and

receiving light at the plurality of photo detectors, the light including at least one of ambient light and reflected light, the reflected light including the at least one infrared frequency, each of the plurality of photo detectors configured to generate an electrical signal proportional to the reflected light received by the photo detector;

adjusting the electrical signal from each of the plurality of photo detectors based on calibrating the plurality of photo detectors to produce adjusted electrical signals; and

determining the proximity in response to the adjusted electrical signals.