阅读说明：本技术 具有方向灵敏度的光传感器 (Optical sensor with directional sensitivity ) 是由 W.劳赫 于 2020-03-26 设计创作，主要内容包括：一种装置包括具有方向灵敏度的光传感器。光传感器包括布置在相同孔径下方的多个光敏元件。每个光敏元件具有通过孔径的相应视场,该视场不同于其他光敏元件的视场。来自光传感器的信号可以便于确定入射光的方向。(An apparatus includes a light sensor having a directional sensitivity. The light sensor includes a plurality of light sensitive elements arranged below the same aperture. Each photosensitive element has a respective field of view through the aperture that is different from the fields of view of the other photosensitive elements. The signal from the light sensor may facilitate determining the direction of the incident light.)

1. An apparatus, comprising:

a light sensor having a directional sensitivity, wherein the light sensor comprises a plurality of light sensitive elements arranged below a same aperture,

wherein each photosensitive element has a respective field of view through the aperture that is different from the fields of view of the other photosensitive elements.

2. The apparatus of claim 1, further comprising an electronic control unit operable to determine a direction of received light based on output signals from one or more of the photosensitive elements and based on respective fields of view of the photosensitive elements.

3. The device of any preceding claim, wherein the photosensitive elements are collectively arranged over an area greater than a cross-sectional area of the aperture.

4. The device of any preceding claim, wherein the photosensitive element comprises a pinned diode.

5. The device of any preceding claim, wherein at least some of the respective fields of view of the photosensitive elements partially overlap each other.

6. The device of any one of claims 1 to 5, wherein the photosensitive element is in a semiconductor substrate, the device further comprising at least one metal layer having an opening of a size that defines the aperture.

7. The apparatus of any one of claims 1 to 5, comprising a black mask filter having openings defining the size of the pore size.

8. The device of any preceding claim, wherein the plurality of photosensitive elements is a two-dimensional array of photodetectors.

9. The apparatus of any preceding claim, wherein the light sensor is arranged in a portable host computing device.

10. The apparatus of claim 2, wherein the electronic control unit is operable to use information about the determined detection in conjunction with gesture recognition.

11. The apparatus of claim 2, wherein the electronic control unit is operable to use information about the determined detection in conjunction with proximity sensing.

12. The apparatus of claim 2, wherein the electronic control unit is operable to use information about the determined detection in conjunction with ambient light sensing.

13. The apparatus of claim 2, wherein the electronic control unit is operable to use information about the determined detection in conjunction with color sensing.

14. The apparatus of claim 2, wherein the electronic control unit is operable to use information about the determined detection in conjunction with time-of-flight sensing.

15. The apparatus of claim 2, wherein the electronic control unit is operable to process signals from the light sensitive elements to determine whether the received light is diffuse.

16. The apparatus of claim 2, wherein the electronic control unit is operable to process signals from the photosensitive elements to determine whether the received light is from more than one source.

17. An apparatus, comprising:

a photosensor having directional sensitivity, wherein the photosensor comprises an array of pinned diodes arranged below a same aperture, wherein each of the pinned diodes has a respective field of view through the aperture that is different from the fields of view of the other pinned diodes, wherein the pinned diodes are collectively arranged over an area that is larger than the cross-sectional area of the aperture;

at least one metal layer having an opening of a size that defines the aperture; and

an electronic control unit operable to determine a direction of received light based on output signals from one or more of the pinned diodes and based on respective fields of view of the pinned diodes.

Technical Field

The present disclosure relates to a light sensor having directional sensitivity.

Background

Various consumer electronic products, such as smart phones and other portable host computing devices, include compact photovoltaic modules with integrated light sensing and/or lighting devices. Some of these modules are configured to determine from which direction the optical signal is received.

Disclosure of Invention

The present disclosure describes devices that include a light sensor with directional sensitivity. The light sensor includes a plurality of light sensitive elements arranged below the same aperture. Each photosensitive element has a respective field of view through the aperture that is different from the fields of view of the other photosensitive elements.

In some embodiments, the apparatus further comprises an electronic control unit operable to determine the direction of the received light based on one or more output signals from the light sensitive elements and based on the respective fields of view of the light sensitive elements.

In some cases, the photosensitive elements are arranged across an area larger than the cross-sectional area of the aperture. The photosensitive element may be implemented as, for example, a pinned diode, although a type of photodetector may also be used. In some embodiments, the photosensitive elements form a two-dimensional array of photodetectors.

In some cases, at least some of the respective fields of view of the photosensitive elements partially overlap one another.

The photosensitive element may be formed, for example, in a semiconductor substrate, and the apparatus may include at least one metal layer having an opening that defines the size of the aperture. In other embodiments, the black mask filter or other layer has openings that define an aperture size.

The light sensor may be disposed, for example, in a portable host computing device (e.g., a smartphone, a tablet, a wearable device, a Personal Digital Assistant (PDA), or a personal computer). Depending on the application, the electronic control unit is operable to use information about the determined detection in combination with gesture recognition, proximity sensing, ambient light sensing, color sensing and/or time of flight (TOF) sensing. In some cases, the electronic control unit is operable to process signals from the light sensitive elements to determine whether the received light is diffuse or whether the received light is from more than one light source.

In some embodiments, the light sensor may be ultra-small and may achieve improved directional sensitivity at relatively low manufacturing costs.

Other aspects, features, and advantages will become apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

Fig. 1 shows an example of a sensor module.

Fig. 2 is a schematic side view of a light sensor.

Fig. 3 is a schematic top view of a light sensor.

FIG. 4 illustrates further details of a light sensor according to certain embodiments.

Detailed Description

In general, the optoelectronic modules described in this disclosure have light sensors, and may also include illumination sources, each of which may be implemented, for example, in a respective die (e.g., an integrated circuit semiconductor chip). In some cases, light generated by the illumination source is emitted from the module toward an object that reflects a portion of the light back to the module where it can be detected at the light receiver. In some cases (e.g., for gesture recognition), it is desirable to be able to detect from which direction light detected in the module is received.

Fig. 1 shows an example of a sensor module 10, the sensor module 10 including an illumination source 12 operable to generate light and a light sensor 14 operable to sense light of a wavelength (e.g., Infrared (IR), near-infrared, visible, or Ultraviolet (UV)) generated by the illumination source 12. The illumination source may include one or more light emitters, examples of which include light emitting diodes, infrared light emitting diodes, organic light emitting diodes, infrared laser diodes, Vertical Cavity Surface Emitting Lasers (VCSELs), and arrays of such devices. In some cases, the module includes passive optical components (e.g., lenses, prisms, mirrors) that redirect light by refraction and/or diffraction and/or reflection. The dies of illumination source 12 and light sensor 14 may be mounted on and electrically coupled to a Printed Circuit Board (PCB) 18 of a host device (e.g., a portable computing device such as a smartphone, tablet, wearable device, Personal Digital Assistant (PDA), or personal computer). According to an embodiment, the electrical connection may include one or more of a die pad, a surface mount connection, a wire bond, or a solder ball.

In the illustrated example, the illumination source 12 and the light sensor 14 are laterally surrounded by a spacer or housing wall 20, and in some cases the spacer or housing wall 20 is opaque to wavelengths produced by the illumination source 12 and sensed by the light sensor 14. The inner wall 22 may separate the illumination source 12 and the light sensor 14 from each other, which helps reduce internal optical crosstalk. In some embodiments, the inner wall 22 may not be present. The module 10 may be disposed behind a back surface 25 of a cover glass 24 of a host device, for example.

To provide directional sensitivity, the light sensor 14 includes a plurality of light sensitive elements (i.e., two or more) arranged below the same aperture such that each light sensitive element has a field of view (FOV) that is different from the other light sensitive elements. An example is shown in fig. 2 and 3, which will be discussed in more detail below.

As shown in fig. 2 and 3, the light sensor 14 includes a plurality of light sensitive elements 30 (i.e., two or more) disposed below the same aperture 32. The photosensitive element 30 may be implemented as, for example, a pinned diode, a photodiode, a single-photon avalanche diode (SPAD), or other light detection device. In some cases, pinned diodes are particularly advantageous due to their small volume. For example, for some mobile camera sensors, the pixel size may be about 1.1 μm by 1.1 μm. Different sizes, including smaller pinned diodes (e.g., 0.2 μ x 0.2 μm), may be used in other embodiments. The photosensitive elements 30 can be arranged in, for example, an MxN array (where each of M and N is greater than 1) or a linear array. For example, FIG. 3 shows a 3 × 4 array of photosensitive elements 30, although a dimensional array may also be used. In other cases, the photosensors 30 may be arranged in some other configuration.

In general, the photosensor 30 should be disposed in a region larger than the cross-sectional area of the aperture 32 (i.e., in a plane parallel to the plane of the substrate 18) (see, e.g., fig. 3). Thus, each photosensitive element 30 has a field of view that is different from the fields of view of the other photosensitive elements. Fig. 2 shows the FOV 34 of one light sensitive element 30. Although the respective fields of view of the photosensors 30 are different from each other, they may partially overlap.

As shown in fig. 4, aperture 32 may be defined by depositing one or more metal layers 36 directly on a semiconductor (e.g., silicon) substrate in which the photosensitive element is formed. Fig. 4 shows the fields of view 34A, 34B, 34C of the three photosensors 30A, 30B, 30C, respectively. In the illustrated example, top metal layer 36A has an opening that defines the size of aperture 32. In some cases, the distance between the photosensitive silicon surface and the top metal layer 36A is about 1 μm. Different values may be applicable to other embodiments. One advantage of forming the aperture by a stack of one or more metal layers is that it allows the aperture to be formed using standard CMOS processes. However, in some embodiments, the apertures may be formed in other ways. For example, the aperture 32 may be defined by a small opening in the black mask filter (e.g., if the distance to the photosensitive element is relatively large, such as in the range of 5-10 μm). In other embodiments, some other layer capable of blocking incident light (e.g., a white or reflective filter) may be used to define the apertures 32.

The signals sensed by the light sensor 14 may be read out and processed by an Electronic Control Unit (ECU)28 (see fig. 1), the electronic control unit 28 being either in the sensor module 10 itself or in a host device in which the module is arranged. The electronic control unit 28 may be implemented, for example, as an integrated circuit chip or other processor, and may include software stored in memory. Electronic control unit 28 may include appropriate logic and/or other hardware components (e.g., read registers, amplifiers, analog-to-digital converters, clock drivers, timing logic, signal processing circuitry, and/or a microprocessor). In some cases, electronic control unit 28 (or a portion thereof) may be integrated into the same IC chip as light sensor 22.

The electronic control unit 28 is operable to determine, among other things, in which direction the detected light is received in the module 10. This may be accomplished, for example, by identifying which photosensitive element 30 generates the largest output signal (e.g., after accounting for noise or optical cross-talk) and using that information along with stored information about the FOV of the particular photosensitive element 30 to identify the direction of the incident light. In some cases, more than one photosensor 30 may detect signals at the same time. The electronic control unit 28 may then analyze the signal output by the light sensitive element 30 based on, for example, the relative amplitude of the signal, and use this information, along with stored knowledge of the field of view of the light sensitive element, to estimate from which direction the detected light was received. In some cases, the electronic control unit 28 is operable to process the signals from the light sensitive elements 30 to determine whether the light is diffuse or from one or more light sources (e.g., spotlights).

The knowledge of which direction the light is received from may increase the information available to the electronic control unit 28 about the detected light. This knowledge may be used for a range of different applications including, for example, gesture recognition, proximity sensing, ambient light sensing, color sensing and time of flight (TOF) and distance sensing.

For example, gesture recognition has become prominent in portable and wearable devices in the gaming, healthcare, automation, automotive, and consumer electronics fields. In the case of gesture recognition, the electronic control unit 28 may provide a perceptual computing user interface that allows the device to capture and interpret human gestures as commands in a contactless manner. For example, the electronic control unit 28 may use directional information obtained from the photosensor output signals, as well as other information, to determine the physical movement of the user's finger or hand. In some cases, the techniques described above for light sensor 14 may facilitate ultra-low cost solutions that do not require optical lenses or special packaging. For example, the small size may be particularly suited for earplugs where the gesture sensor may be used to control sound (e.g., loudness, mute, or turn off) without requiring the user to touch the device.

In the case of proximity sensors, knowing from which direction the detected light comes can help distinguish, in some cases, which portions of the received light come from crosstalk, from reflections from the cover glass or stains on the cover glass of the host device, or from objects in front of the host device.

In the case of an ambient light sensor, knowing from which direction the detected light comes can, in some cases, help determine how strong the reflection is and to what extent the ambient light may blind the user of the host device. Electronic control unit 28 may be configured with an intelligent algorithm to adjust, for example, the brightness of the host device display screen based on ambient light conditions.

In the case of color sensors (e.g., red, green, blue, and transparent), knowing from which direction the detected light comes may, in some cases, help the electronic control unit 28 to estimate the color temperature of the light coming from different directions. A detailed knowledge of the light line features can provide significant advantages for near perfect white balance. For example, such knowledge may indicate diffuse or intense light on one side.

In the case of TOF sensors, knowing which direction the detected light comes from may, in some cases, allow the sensor to identify targets in different directions, which may facilitate an ultra-low cost multi-area sensor, where no lens is required.

Sensors of the type described above may be integrated into, for example, a smartphone or other portable host computing device (e.g., a tablet, wearable device, Personal Digital Assistant (PDA), or personal computer). The design of such a device referred to may include one or more processors, one or more memories (e.g., random access memory, RAM), storage devices (e.g., disk or flash memory), a user interface (which may include, for example, a keyboard, a thin film transistor liquid crystal display TFT LCD or OLED display screen, touch or other gesture sensors, cameras or other light sensors, compass sensors, a 3D magnetometer, a three-axis accelerometer, a three-axis gyroscope, one or more microphones, etc., along with software instructions for providing a graphical user interface), interconnections between these elements (e.g., a bus), and interfaces for communicating with other devices (which may be wireless, such as GSM, 3G, 4G, CDMA, WiFi, WiMax, Zigbee, or bluetooth, and/or wired, such as through an ethernet local area network, T-1 internet connection, etc.).

Various aspects of the subject matter and the functional operations described in this specification, for example, aspects related to circuitry 28, may be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Accordingly, aspects of the subject matter described in this specification can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more of them. The apparatus may comprise, in addition to hardware, code that creates an execution environment for the computer program in question, e.g. code that constitutes processor firmware.

A computer program (also known as a program, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC).

Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

While this specification contains many specifics, these should not be construed as limitations on the scope of the invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of the invention. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Many implementations have been described. Nevertheless, various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other implementations are within the scope of the following claims.