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Sony IMX611: Efficient ToF sensor could be destined for iPhone 15 Pro

Mar 6, 2023

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Sony's IMX611 is a new direct time-of-flight (dToF) sensor developed for smartphones, which, with an adapted pixel structure, is said to have the highest efficiency to date in detecting photons. Sony also mentions improvements in energy consumption. The sensor could be for the iPhone 15 Pro (Max).

The new dToF sensor was developed by Sony Semiconductor Solutions Corporation (SSS) and, according to the provider, is currently being sampled for 1,000 yen per unit, i.e. just under 7 euros. The IMX611 uses a proprietary “single-photon avalanche diode” (SPAD) pixel structure, which is said to offer advantages in power consumption and distance measurement. The sensor was designed for use in connection with smartphone cameras in order to optimize the autofocus in poor lighting conditions, calculate a bokeh effect for portrait shots, record rooms in three dimensions or carry out calculations for augmented reality. The IMX611 should also be useful for the evolution of VR HMDs and AR glasses.

Highest efficiency in photon identification

Among the time-of-flight sensors developed specifically for smartphones, Sony advertises the IMX611 with the highest efficiency to date of 28 percent in detecting photons when using a laser light source with a wavelength of 940 nm, which Sony says is common in smartphones may be. Sony specifies the power consumption for the sensor alone as 110 mW for measurements from a distance of 8 m, and 160 mW for the entire system with a laser light source. At a short distance (3 m), consumption is 40 mW (sensor) and 85 mW (system). According to Sony, the error rate when measuring distances is less than 0.1 percent.

Pixel and logic chip in one package

Sensors like the IMX611 capture photons reflected from objects and use that information to calculate distance. In order to also be able to detect particularly weak photons and to still be able to carry out the distance measurement even with a weak laser light source, Sony relies on a light incidence level on the pixe chip that is deliberately provided with irregularities in order to break up the incident light and thus ensure a higher absorption rate. In the so-called avalanche region of the pixel, where the avalanche effect can be brought about, there have also been optimizations for efficient multiplication. In the multiplication zone, the number of free charge carriers increases like an avalanche, hence the name.

A copper-to-copper connection is used for the transfer from the pixel to the logic chip, with the data also being processed in the logic chip in order to once again increase efficiency. The raw data of the SPAD pixels are converted into distance information in the logic chip and then to a corresponding output, so that the load for later post-processing is reduced.

Sensor might be intended for iPhone 15 Pro

The IMX611 could be used for the first time in the Apple iPhone 15 Pro and iPhone 15 Pro Max, which are expected for late summer. Sony itself does not name any buyers for the sensor, but the analyst Ming-Chi Kuo, who is often correct in his statements, reported from supplier circles at the end of February that Apple for the two new smartphones for the dToF sensor from Lumentum (design) and Win Semi (Production) will be switching exclusively to Sony.