US-12628452-B2 - Electronic devices having semiconductor sensors with metal optical filters

US12628452B2US 12628452 B2US12628452 B2US 12628452B2US-12628452-B2

Abstract

An electronic device may include an ambient light sensor or other semiconductor sensor. The sensor may produce signals in response to light incident on the electronic device and therefore incident on the sensor. In some cases, components within the electronic device, such as infrared components, or external light sources may interfere with the operation of the sensor. Therefore, the sensor may include a filter that transmits at least a portion of visible light while blocking infrared light. Because light may be incident on the electronic device from a variety of angles, a diffuser in the sensor may scatter the light into a desired angular distribution. To ensure that infrared light is blocked regardless of the angle of the incident light, the filter may include both thin-film dielectric layers and metal layers. The metal layers may be interleaved with the thin-film dielectric layers.

Inventors

Ove Lyngnes
Paul J Gelsinger
Yijing Chen
Guocheng SHAO
Louis W Baum
Kenneth J Vampola
Avery P Yuen

Assignees

APPLE INC.

Dates

Publication Date: 20260512
Application Date: 20230328

Claims (16)

1 . An ambient light sensor configured to provide ambient light measurements to control circuitry in an electronic device, the ambient light sensor comprising: a substrate; a light detector integrated circuit on the substrate; and a filter on the light detector integrated circuit, wherein the filter comprises a thin-film interference filter that includes a plurality of thin-film dielectric layers and multiple metal layers interleaved with the plurality of thin-film dielectric layers.
2 . The ambient light sensor defined in claim 1 , further comprising: a diffuser, wherein the filter is interposed between the diffuser and the substrate.
3 . The ambient light sensor defined in claim 2 , wherein the thin-film interference filter is a band pass filter.
4 . The ambient light sensor defined in claim 3 , wherein the multiple metal layers comprises at least one of a silver layer, an aluminum layer, or a gold layer.
5 . The ambient light sensor defined in claim 4 , wherein the plurality of thin-film dielectric layers comprises a stack of dielectric layers with alternating high and low indices of refraction.
6 . The ambient light sensor defined in claim 3 , wherein the band pass filter is configured to pass a respective range of visible light wavelengths while blocking at least 95% of infrared light.
7 . The ambient light sensor defined in claim 2 , wherein the light detector integrated circuit comprises a plurality of photodetectors.
8 . The ambient light sensor defined in claim 7 , wherein the filter and the diffuser overlap the plurality of photodetectors.
9 . The ambient light sensor defined in claim 7 , wherein the filter is one of a plurality of filters that each respectively overlaps a given one of the plurality of photodetectors and wherein the diffuser overlaps the plurality of photodetectors.
10 . An electronic device, comprising: a transparent layer; an optical component window in a portion of the transparent layer through which light passes; and a light sensor aligned with the optical component window, wherein the light sensor comprises: a substrate; a light detector integrated circuit on the substrate; a filter that overlaps the light detector integrated circuit, wherein the filter comprises a metal layer; a diffuser, wherein the filter is interposed between the diffuser and the substrate; and a spacer between the diffuser and the filter and wherein the spacer, the diffuser, and the filter are stacked on the substrate and the light detector integrated circuit, wherein the spacer extends across the filter from a first edge to a second edge.
11 . The electronic device defined in claim 10 , wherein the filter is a thin-film interference filter that further comprises a stack of thin-film dielectric layers.
12 . The electronic device defined in claim 11 , wherein the metal layer is interposed between thin-film inorganic dielectric layers of the stack of thin-film dielectric layers.
13 . The electronic device defined in claim 12 , wherein the thin-film dielectric layers have alternating high and low indices of refraction.
14 . A semiconductor device configured to generate signals in response to incident light, comprising; a substrate; a light detector integrated circuit on the substrate; a diffuser that overlaps the substrate and the light detector integrated circuit; and a filter interposed between the diffuser and the substrate, wherein the filter comprises a stack of thin-film dielectric layers with alternating high and low indices of refraction and a plurality of metal layers interleaved with the stack of thin-film dielectric layers.
15 . The semiconductor device defined in claim 14 , wherein the diffuser and the filter are coupled to the substrate and the light detector integrated circuit without any air gaps.
16 . The semiconductor device defined in claim 14 , wherein the filter is a band pass filter.

Description

This application claims the benefit of provisional patent application No. 63/350,994, filed Jun. 10, 2022, which is hereby incorporated by reference herein in its entirety. FIELD This relates generally to electronic devices, and, more particularly, to electronic devices with optical components. BACKGROUND Electronic devices such as laptop computers, cellular telephones, and other equipment are sometimes provided with optical components. For example, an electronic device may have an ambient light sensor, an optical proximity sensor, image sensors, and light sources. The desire to include multiple optical components in an electronic device can pose challenges. It can be difficult to incorporate optical components into an electronic device where space is at a premium. There is also a potential for different optical components to interfere with each other during operation. SUMMARY An electronic device may be provided with a display mounted in a housing. The display may have an active area with an array of pixels for forming images and may have an inactive area along one or more edges of the active area. Optical component windows may be formed in the inactive area, under the display in the active area, and/or in other portions of the electronic device. Optical components such as light-emitting diodes, image sensors, optical proximity sensors, and ambient light sensors may be aligned with the optical component windows. An ambient light sensor may have a light detector integrated circuit with photodetectors. To provide the ambient light sensor with color sensing capabilities, the photodetectors may each be provided with a respective color filter configured to pass a different range of wavelengths. A diffuser may be used to diffuse incoming ambient light. Infrared light-blocking filter layers may be use to block infrared light such as infrared light emitted by an infrared light-emitting diode in the electronic device and other stray or ambient infrared light. To block infrared light regardless of its angle of incidence on the infrared-blocking filter, the filter may include both thin-film dielectric layers and metal layers. For example, the metal layers may be interleaved with the thin-film dielectric layers and block infrared light. Together, the thin-film dielectric layers and metal layers may form a pass band in at least some visible light wavelengths, while blocking infrared wavelengths. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an illustrative electronic device having optical components in accordance with an embodiment. FIG. 2 is a perspective view of an illustrative electronic device with a display having optical component windows overlapping optical components in accordance with an embodiment. FIG. 3 is a side view of an illustrative electronic device that has optical components such as a light source, image sensor, and ambient light sensor in accordance with an embodiment. FIG. 4 is a side view of an illustrative semiconductor sensor in accordance with an embodiment. FIG. 5 is a side view of an illustrative diffuser in accordance with an embodiment. FIG. 6 is a side view of an illustrative filter in accordance with an embodiment. FIG. 7 is a graph of an illustrative transmission profile as a function of wavelength for a filter in accordance with an embodiment. FIG. 8A is a top view of an illustrative ambient light sensor integrated circuit having a set of photodetectors with a circular outline in accordance with an embodiment. FIG. 8B is a top view of an illustrative ambient light sensor having a set of photodetectors with a rectangular outline in accordance with an embodiment. FIG. 9A is a side view of an illustrative ambient light sensor having a stack of a diffuser, a spacer, and a filter overlapping multiple photodetectors in accordance with an embodiment. FIG. 9B is a side view of an illustrative ambient light sensor having individual stacks of a diffuser, a spacer, and a filter, each stack overlapping a respective photodetector in accordance with an embodiment. DETAILED DESCRIPTION An illustrative electronic device of the type that may be provided with optical components such as ambient light sensors or other semiconductor sensors is shown in FIG. 1. Electronic device 10 may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user's head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of the