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Yesterday Patently Apple posted a report titled " A Federal Judge Has Dismissed a Proposed Class-Action against Apple over Water Resistance Claims. The Judge stated that the Plaintiffs didn't provide evidence of an iPhone damaged by liquid contact and found no proof of fraud relating to overstating its water resistance claims. Apple dedicates a support page that clarifies what their "splash and water resistance" means.
Coincidentally, the US Patent & Trademark Office published a patent application from Apple yesterday titled "Integrated water detection and ejection for Ceramic Substrates," which details their latest water detecting and ejecting sensor device.
According to Apple's patent filing, the subject technology is directed to an integrated water detection and ejection mechanism for sensor devices with ceramic substrates. The integrated sensor device of the subject technology is water resistant, as it has provisions for detecting the presence of water and ejecting the water by causing it to evaporate. Gel-filled sensors have been used in wearable devices (e.g., smartwatches) to survive exposure to water and environmental contaminants, such as dust, sand and other debris.
Pressure sensors using interim gel have been widely used in microelectronic devices, but the gel-filled pressure sensors are vulnerable to pressure errors due to a number of issues. For example, the gel-filled sensors suffer from orientation sensitivity and are susceptible to change of gel-package boundary conditions due to chemical and/or mechanical accumulation. Furthermore, in a gel-filled sensor, capillary pressure errors can occur due to presence of water in the gel surface.
Existing solutions for gel elimination use organic materials such as expanded-polytetrafluoroethylene (ePTFE) membrane or mesh to provide environmental robustness. However, ePTFE is incompatible with ceramic substrate lamination temperatures. For instance, when wet, ePTFE does not allow water detection via orientation sensitivity (as a gel-filled sensor would) as it cannot provide a water-detection signal.
Ceramic is desirable as a substrate material as it affords much greater strain resistance as compared with traditional organic substrates.
In particular, strain resistance is desirable for pressure sensors to reduce errors due to mechanical loading on the device that can be transferred to the sensor via the substrate. On the other hand, organic substrates are compatible with organic substrate lamination temperatures.
The subject technology utilizes one or more tightly woven metal mesh layers (e.g., stainless steel, and hereinafter, mesh layer) and laminates the mesh layers between a number of ceramic layers, which forms a parallel plate capacitor.
The mesh layer affords significant environmental ingress protection while eliminating the orientation sensitivity error associated with gel-filled sensors. When the sensor is completely dry, air forms the dielectric medium between mesh-layer parallel plates and produces a first capacitance value (C-dry). When the sensor is wet, water trapped between the two mesh-layer parallel plates changes the dielectric constant and hence the capacitance value to a second capacitance value (C-wet).
An integrated circuit (IC) or a microcontroller (.mu.C) can be used to distinguish between wet and dry conditions for the sensor. When the IC or .mu.C determines that the sensor is wet, it can apply a direct current (DC) voltage across the mesh-layer parallel plates with trapped water (effectively a resistor). Current can flow through the water and cause the mesh-layer parallel plates to heat up and evaporate the accumulated water (water ejection).
As the water evaporates, the resistance will start to increase, reducing the current flow. Once zero current flow is detected, the water is fully ejected and can be verified by switching back to the detection circuit.
Apple's patent FIGS. 1A and 1B are schematic diagrams illustrating a cross-sectional view and a top view of an example integrated water-resistant sensor device.
Apple's patent FIG. 4 above is a flow diagram illustrating a functional process of an example integrated. water-resistant sensor device.
Lastly, Apple notes that in some implementations, when the presence of water is detected, the host device (e.g., smartphone or smartwatch) can disregard the pressure sensor and instead rely on other modes of detecting motion such as using an accelerometer or a gyro of the host device to avoid false flights and/or exercise minutes resulting from capillary pressure errors as the water dries.
For more details, review Apple's patent application number 20220039211.
Considering that the patent was originally filed for in July 2020, it's very possible that Apple used this technology in the 2021 iPhone 13. However, while iFixit generally mentions the iPhone's IP68 water-resistance rating in their teardown, they didn't specifically cover Apple's technology supporting that rating.
Posted by Jack Purcher on February 04, 2022 at 05:57 AM in 1A. Patent Applications, Apple iPhone, Apple Watch, Smart Bands &Wearables, Sensors, Chips & Haptics | Permalink | Comments (0)
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