Retroreflective mechanism on optical ranging, proximity and image sensors for reducing optical noise from undesired sources

Abstract

The present disclosure relates to retroreflective mechanisms on optical ranging, proximity and image sensors for reducing optical noise from undesired sources. An example electronic system utilizes an optical ranging, proximity, and / or image sensor configured with a retroreflective mechanism to reduce undesired optical noise at an optical radiation receiver. An example ranging, proximity, and / or image sensor is configured to include a housing cover having a transmit opening and a receive opening. The example sensor may also include a light radiation source positioned to direct ranging light radiation through the emission opening toward the target object. The optical radiation receiver is positioned to receive the ranging optical radiation reflected from the target object through the receiving opening. A retroreflective mechanism implemented on the surface of the housing cover directs the undesired optical noise back toward the undesired optical noise source and away from the optical radiation receiver. Attributes of the target object may be determined based on one or more attributes of the ranging optical radiation received at the optical radiation receiver.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to noise reduction mechanisms on optical sensors (e.g., optical ranging sensors, optical proximity sensors, and / or optical image sensors), and more particularly, to utilizing a retroreflective mechanism on a surface of an optical sensor housing cover to reduce optical noise from undesired sources. Background Art

[0002] Various example embodiments address technical issues associated with optical noise from undesired sources in optical ranging, proximity or image sensors. During operation of an optical ranging sensor, light may be received from a variety of sources, including reflections from a target object, reflections from multiple surfaces of the optical ranging sensor and its external cover, and / or light from ambient sources. Light from undesired sources, such as reflections from multiple surfaces of the optical ranging sensor and / or light from ambient sources, increases the noise received at the optical radiation receiver and reduces the signal-to-noise ratio (SNR) of the reflections from the target object. The increased noise may cause inaccurate and / or inconsistent readings from the optical ranging sensor.

[0003] Applicants have discovered a number of technical challenges and difficulties associated with reducing received optical noise at an optical radiation receiver of an optical ranging, proximity or image sensor. Through exertion of effort, ingenuity and innovation, Applicants have solved the problems associated with received optical noise in optical ranging sensors by developing solutions embodied in the present disclosure, which solutions are described in detail below. Summary of the invention

[0004] Various embodiments are directed to an example optical ranging sensor and an example electronic system including an optical ranging sensor configured to reduce undesired optical noise at an optical radiation receiver. An example optical ranging sensor configured to determine the proximity of a target object may include a housing cover including a transmitting opening and a receiving opening. The example optical ranging sensor may also include an optical radiation source positioned to direct the ranging optical radiation through the transmitting opening toward the target object, an optical radiation receiver positioned to receive the ranging optical radiation reflected from the target object through the receiving opening, and a retro-reflective mechanism implemented on a surface of the housing cover. In some embodiments, the retro-reflective mechanism directs the undesired optical noise back toward the undesired optical noise source and away from the optical radiation receiver. The proximity of the target object may be determined based on one or more properties of the ranging optical radiation received at the optical radiation receiver.

[0005] In some embodiments, the housing cover further comprises a top surface opposite the optical radiation receiver, wherein the retroreflective mechanism is disposed such that the top surface of the housing cover is substantially covered.

[0006] In some embodiments, a portion of the housing cover between the receiving opening and the transmitting opening includes the retro-reflective mechanism.

[0007] In some embodiments, one or more opening surfaces defining the transmitting opening and the receiving opening include the retro-reflective mechanism.

[0008] In some embodiments, one or more blocking surfaces positioned between the optical radiation source and the optical radiation receiver include the retro-reflective mechanism.

[0009] In some embodiments, the optical ranging sensor may further include a receiving optical structure positioned between the optical radiation receiver and the target object, wherein the receiving optical structure is configured to direct the ranging optical radiation toward the optical radiation receiver.

[0010] In some embodiments, the optical ranging sensor may further include a transmitting optical structure positioned between the optical radiation source and the target object, wherein the transmitting optical structure is configured to direct the ranging optical radiation toward the target object.

[0011] In some embodiments, the retroreflective mechanism comprises a corner retroreflector.

[0012] In some embodiments, the retroreflective mechanism comprises a cat's eye retroreflector.

[0013] In some embodiments, the retroreflective mechanism includes at least one of a retroreflective paint and a retroreflective tape.

[0014] In some embodiments, the one or more properties of the ranging optical radiation include at least one of a time of flight of the optical radiation and an intensity of the optical radiation.

[0015] In some embodiments, the proximity of the target object includes at least one of a distance of the target object from the optical ranging sensor, a position of the target object relative to the optical ranging sensor, and a speed of the target object.

[0016] An example electronic system configured to determine the proximity of a target object is also provided. In some embodiments, the example electronic system may include an outer cover and an optical ranging sensor disposed on an inner side of the outer cover, opposite the target object. The optical ranging sensor may include: a housing cover including an emission opening and a receiving opening; an optical radiation source positioned to direct ranging optical radiation through the emission opening toward the target object; an optical radiation receiver positioned to receive ranging optical radiation reflected from the target object through the receiving opening; and a retro-reflective mechanism disposed on a surface of the housing cover, wherein the retro-reflective mechanism directs undesirable optical noise back toward the optical noise source and away from the optical radiation receiver. In some embodiments, the proximity of the target object is determined based on one or more properties of the ranging optical radiation.

[0017] In some embodiments, the housing cover further comprises a top surface opposite the optical radiation receiver, wherein the retroreflective mechanism is disposed such that the top surface of the housing cover is substantially covered.

[0018] In some embodiments, a portion of the housing cover between the receiving opening and the transmitting opening includes the retro-reflective mechanism.

[0019] In some embodiments, one or more opening surfaces defining the transmitting opening and the receiving opening include the retro-reflective mechanism.

[0020] In some embodiments, one or more blocking surfaces positioned between the optical radiation source and the optical radiation receiver include the retro-reflective mechanism.

[0021] In some embodiments, the retroreflective mechanism includes at least one of a corner retroreflector and a cat's eye retroreflector.

[0022] In some embodiments, the retroreflective mechanism includes at least one of a retroreflective paint and a retroreflective tape.

[0023] In some embodiments, the proximity of the target object includes at least one of a distance of the target object from the optical ranging sensor, a position of the target object relative to the optical ranging sensor, and a speed of the target object. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Reference will now be made to the drawings. The components shown in the various figures may or may not be present in certain embodiments described herein. According to example embodiments of the present disclosure, some embodiments may include fewer (or more) components than those shown in the various figures.

[0025] Figure 1 A cross-sectional view of an example optical ranging system that receives undesirable optical noise from various sources at an optical radiation receiver is shown according to an example embodiment of the present disclosure.

[0026] Figure 2A-2B A cross-sectional view of an example housing cover assembly including a retroreflective mechanism according to an example embodiment of the present disclosure is shown.

[0027] Figure 3 A cross-sectional view of an example housing cover including a retroreflective mechanism positioned on a top surface of the housing cover is shown according to an example embodiment of the present disclosure.

[0028] Figure 4 A cross-sectional view of an example housing cover including a retroreflective mechanism positioned on a top surface of the housing cover between a transmit opening and a receive opening according to an example embodiment of the present disclosure is shown.

[0029] Figure 5 A cross-sectional view of an example optical ranging system including a retro-reflective mechanism positioned to reflect undesirable optical noise away from an optical radiation receiver is shown according to an example embodiment of the present disclosure.

[0030] Figure 6A-6B Illustrated is a cross-sectional view of an example retroreflective mechanism including a corner retroreflector and a cat's eye retroreflector according to an example embodiment of the present disclosure.

[0031] Figure 7 Several example electronic systems utilizing optical ranging sensors according to example embodiments of the present disclosure are shown. DETAILED DESCRIPTION

[0032] Example embodiments will be described more fully below with reference to the accompanying drawings, which show some, but not all, embodiments of the invention of the present disclosure. In fact, the embodiments of the present disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure satisfies applicable legal requirements. The same reference numerals throughout the text represent the same elements.

[0033] Various example embodiments address technical issues associated with receiving optical noise from undesired sources at an optical radiation receiver of an optical ranging, proximity, or image sensor. As will be appreciated by those skilled in the art to which the present disclosure pertains, there are many example scenarios in which the accuracy and consistency of an optical ranging, proximity, or image sensor may be improved by reducing the amount of undesired optical noise received at the optical radiation receiver.

[0034] During operation of the optical ranging sensor, the optical radiation source emits ranging optical radiation. The ranging optical radiation may be directed through one or more transmitting optical structures, a display screen, a cover glass, and / or a lens toward a target object. A portion of the ranging optical radiation may be reflected by the target object and may be received by an optical radiation receiver. The received ranging optical radiation may be correlated with the emitted ranging optical radiation to determine certain characteristics related to the proximity of the target object, such as a distance to the target object, a position of the target object, a motion of the target object, and / or a velocity of the target object.

[0035] In addition to the ranging optical radiation reflected from the target object, optical radiation may also be received from a variety of undesired sources. Optical radiation (or undesired optical noise) received from undesired sources may weaken the reflected ranging optical radiation. For example, optical radiation from undesired sources (such as but not limited to reflections from multiple surfaces and / or external covers of the optical ranging sensor and / or any object not including the target, and / or light from environmental sources) increases the noise received at the optical radiation receiver. The increase in undesired optical noise is equivalent to a decrease in the signal-to-noise ratio (SNR) of the ranging optical radiation reflected from the target object. Due to the reduction in SNR caused by undesired optical noise, the proximity output from the optical ranging sensor becomes increasingly inaccurate and inconsistent.

[0036] In some examples, mitigating the reception of undesirable optical noise has included selecting housing materials and positioning reflective surfaces. For example, an optical ranging sensor manufacturer may select materials to absorb one or more wavelengths of light. However, these materials often have material limitations in terms of the necessary properties of the housing cover. In addition, an optical ranging sensor manufacturer may select materials and / or surfaces that randomly and diffusely reflect any incident light. Such options may randomly reflect light toward an optical radiation receiver, etc.

[0037] Various example embodiments described herein utilize various techniques to direct unwanted optical noise away from the optical radiation receiver of the optical ranging sensor. For example, in some embodiments, one or more retro-reflective mechanisms may be provided on multiple surfaces of a housing cover of the optical ranging sensor to limit the amount of unwanted optical noise received at the optical sensor.

[0038] In general, the retroreflective mechanism returns the directed optical radiation in the direction of the optical radiation source. By directing the optical radiation toward the optical radiation source, the optical radiation is directed away from the optical radiation receiver. The retroreflective mechanism may include a corner retroreflector, a cat's eye retroreflector, a retroreflective coating, a retroreflective tape, etc. In some embodiments, the retroreflective mechanism may be added to all surfaces of the housing cover, including the top surface of the housing cover, the inner surface of the housing cover, the opening surface of the housing, the blocking surface of the housing cover, etc. Such a retroreflective mechanism may be incorporated into the surface of the housing cover during the housing cover forming process.

[0039] In addition, in some embodiments, the retro-reflective mechanism can be strategically positioned on the surface of the housing cover where most of the undesirable optical noise is reflected into the optical radiation receiver. For example, in some embodiments, the entire top surface of the housing cover can include the retro-reflective mechanism, while the inner surface, the opening surface, and / or the blocking surface do not include the retro-reflective mechanism. In some example embodiments, only the top surface between the transmitting opening and the receiving opening in the housing cover can include the retro-reflective mechanism.

[0040] By using a retro-reflective mechanism on one or more surfaces of a housing cover of an optical ranging, proximity or image sensor, the amount of undesirable optical noise received at an optical radiation receiver can be greatly reduced. Reducing undesirable optical noise at an optical radiation receiver can improve the performance and overall consistency of the optical ranging, proximity or image device. As a result of the example embodiments and some examples described herein, the effectiveness of the optical ranging, proximity or image sensor can be greatly improved.

[0041] Reference now Figure 1 , shows an example ranging system 100, which includes an optical ranging sensor 102, which operates without retroreflective features. Figure 1 As shown in , the optical ranging system 100 includes an optical ranging sensor 102, which includes an optical radiation source 104, which is configured to direct ranging optical radiation 118 through an emission optical structure 114 (e.g., a lens) placed in an emission opening 126 of a housing cover 108 and through an external cover 116 (e.g., a screen), toward a target object 110. The ranging optical radiation 118 is reflected by the target object 110 and returns through the receiving opening 124 and the receiving optical structure 122 in the housing cover 108 to be received at the optical radiation receiver 106. Figure 1 As further shown in FIG. 1 , the optical radiation source 104 and the optical radiation receiver 106 are electrically connected to a substrate 112 (eg, a printed circuit board). In addition, the housing cover 108 is attached to the substrate 112. Figure 1 As shown in FIG. 1 , various sources of unwanted optical radiation (eg, unwanted ambient optical noise 120 a , unwanted crosstalk optical noise 120 b - 120 e ) are reflected from various surfaces of the housing cover 108 and received at the optical radiation receiver 106 .

[0042] like Figure 1As shown in , the example optical ranging sensor 102 includes an optical radiation source 104. The optical radiation source 104 is any device, bulb, semiconductor, diode, laser, or other photon emitting structure configured to generate ranging optical radiation 118 and positioned to direct the ranging optical radiation 118 toward the target object 110. The optical radiation source 104 may include any light source, such as a laser diode, a light emitting diode, a bulb, a semiconductor device, or other photon emitting structure. In some embodiments, the optical radiation source 104 may include a semiconductor laser diode, for example, a vertical cavity surface emitting laser (VCSEL) and / or an edge emitting laser diode. In general, the optical radiation source 104 may output a coherent light beam when receiving an electric current. In the optical ranging sensor 102, the proximity of the target object 110 in the environment may be measured by generating a pulse or continuous wave ranging optical radiation 118, receiving the reflected pulse or continuous wave ranging optical radiation 118, and determining the flight time of the pulse or continuous wave ranging optical radiation 118. The proximity of the target object 110 may include the distance of the target object 110 from the optical ranging sensor 102 , the position of the target object 110 , the speed of the target object 110 , the direction of movement of the target object 110 , and other similar characteristics related to the position of the target object 110 in the environment.

[0043] like Figure 1 As further shown in , the example optical ranging sensor 102 includes an optical radiation receiver 106. The optical radiation receiver 106 can be any collection of one or more photodiodes, integrated circuits, devices, sensors, light sensing diodes, or other structures that generate an electrical signal as a result of receiving light at the optical radiation receiver 106. For example, the electrical signal output by the optical radiation receiver 106 can increase as the number of photons striking the optical radiation receiver 106 per second increases. In such an embodiment, the current output from the optical radiation receiver 106 can be used to determine the intensity or amplitude of the ranging optical radiation 118 striking the optical radiation receiver 106. In some embodiments, the optical radiation receiver 106 can be a photosensitive semiconductor diode that generates electron-hole pairs at a pn junction when a photon with sufficient energy strikes the optical radiation receiver 106.

[0044] like Figure 1 , the optical radiation receiver 106 is electrically connected to the substrate 112. In some embodiments, the optical radiation receiver 106 may also be electrically connected to a processing device. The processing device may be configured to receive an electrical signal generated by the optical radiation receiver 106, the electrical signal representing the intensity or other properties of the optical radiation received at the optical radiation receiver 106. In some embodiments, the processing device may determine the time of flight of the ranging optical radiation 118 based on the electrical signal received by the optical radiation receiver 106, and determine one or more characteristics related to the physical location of the target object 110.

[0045] like Figure 1 As further shown in FIG. 1 , the optical ranging sensor 102 includes a substrate 112. The substrate 112 is any structure configured to support attachment of the optical ranging sensor 102, including the housing cover 108. In some embodiments, the substrate 112 may include a printed circuit board (PCB) or ceramic alumina that includes electrical connections that connect the optical ranging sensor 102 to a processor, controller, analog-to-digital converter, or other electrical components.

[0046] like Figure 1 As further shown in FIG. 1 , the example optical ranging sensor 102 includes a housing cover 108. The housing cover 108 can be any package, cover, container, or other covering configured to protect the internal electrical components and circuits of the optical ranging sensor 102. The housing cover 108 can include plastic, ceramic, or other protective materials. The housing cover 108 is attached to the substrate 112 to provide stability and further protect the internal electrical components of the optical ranging sensor 102. In some embodiments, the housing cover 108 can also include conductive pins and / or conductive pads to provide electrical connections to the internal electrical components.

[0047] like Figure 1 As further shown in FIG. 1 , the housing cover 108 includes an emission opening 126 and a receiving opening 124. The openings in the housing cover 108 can enable emission and reception of optical radiation entering and leaving the optical ranging sensor 102. For example, the emission opening 126 can be aligned with the emission cone of the optical radiation source 104. The ranging optical radiation 118 from the optical radiation source 104 can pass through the emission opening 126 toward the target object 110. Similarly, the receiving opening 124 can enable reception of reflected ranging optical radiation 118 entering the optical ranging sensor 102, for example, to be received by the optical radiation receiver 106 and analyzed by a processor or other device.

[0048] like Figure 1As further shown in FIG. 1 , the optical radiation source 104 is configured to output ranging optical radiation 118. The ranging optical radiation 118 may be any optical signal emitted by the optical ranging sensor 102 toward the target object 110 for determining a characteristic related to the proximity of the target object 110. In some embodiments, the ranging optical radiation 118 may be a pulsed laser signal. For example, the optical radiation source 104 may be configured to generate uniform laser pulses. Utilizing a pulsed laser signal may enable the controller to determine the time of flight of the ranging optical radiation 118 once the ranging optical radiation is received at the optical radiation receiver 106. In some embodiments, the ranging optical radiation 118 may be a continuous wave laser signal. In such embodiments, the continuous wave laser signal may enable the controller to determine the proximity of the target object 110 by correlating the proximity of the target object 110 with a phase change in the ranging optical radiation 118 when the ranging optical radiation 118 is emitted by the optical radiation source 104, reflected from the target object 110, and subsequently received by the optical radiation receiver 106.

[0049] like Figure 1 As further shown in FIG. 1 , the ranging optical radiation 118 is configured to pass through the emission opening 126. Figure 1 As shown in , in some embodiments, the emission opening 126 includes an emission optical structure 114. The emission optical structure 114 is any transparent and / or translucent device configured to enable the ranging optical radiation 118 to pass through. In some embodiments, the emission optical structure 114 may include an optical lens, an assembly of optical lenses, or other optical devices configured to distort the ranging optical radiation 118. For example, the emission optical structure 114 may point, focus, or direct the ranging optical radiation 118 toward the target object 110 or the dynamic part of the target object 110. In some embodiments, the emission optical structure 114 may be a transparent device positioned to prevent dust, dirt, and other impurities from entering the internal cavity of the optical ranging sensor 102. In some embodiments, the emission optical structure 114 may be a bandpass filter to limit the ranging optical radiation 118 emitted by the optical radiation source 104 to a narrow wavelength range. In some embodiments, the emission optical structure 114 may be positioned on the outer surface of the housing cover 108.

[0050] like Figure 1 As further shown in FIG. 1 , the reflected ranging optical radiation 118 is configured to reflect from the target object 110 and pass through the receiving opening 124. Figure 1As shown in , in some embodiments, the receiving opening 124 includes a receiving optical structure 122. The receiving optical structure 122 is any transparent and / or translucent device configured to allow the reflected ranging optical radiation 118 to pass through. In some embodiments, the receiving optical structure 122 may include an optical lens, an assembly of optical lenses, or other optical devices configured to distort the ranging optical radiation 118 so that the ranging optical radiation 118 is focused on the optical radiation receiver 106. In some embodiments, the receiving optical structure 122 may be a transparent device positioned to prevent dust, dirt, and other impurities from entering the internal cavity of the optical ranging sensor 102. In some embodiments, the receiving optical structure 122 may be a bandpass filter to prevent noise of undesirable wavelengths from reaching the optical radiation receiver 106. In some embodiments, the receiving optical structure 122 may be positioned on the outer surface of the housing cover 108.

[0051] like Figure 1 As further shown in , the optical ranging system 100 may include an external cover 116, such as an electronic display screen. The external cover 116 is any transparent and / or translucent device positioned outside the optical ranging sensor 102 through which the ranging optical radiation 118 passes to encounter the target object 110.

[0052] In some embodiments, the outer cover 116 may be an electronic display screen of an electronic device, such as a mobile phone. In such embodiments, the optical ranging sensor 102 transmits and receives ranging optical radiation 118 through the electronic display screen to determine proximity characteristics of a target object 110 outside the mobile device. The electronic display screen may be any digital display, screen, monitor, or other device configured to output information in a visual form based on received electronic signals. The electronic display screen may be transparent or translucent to certain wavelengths of light, so that the reflected ranging optical radiation 118 may be received by the optical radiation receiver 106 behind or below the electronic display screen.

[0053] In some embodiments, the outer cover 116 may be a protective cover that separates the sensor from external elements. In such embodiments, the optical ranging sensor 102 transmits and receives ranging optical radiation 118 through the outer cover 116 to determine the proximity characteristics of the target object 110 outside the mobile device. The outer cover 116 may be any barrier that protects the sensor and other components from any foreign matter, such as, but not limited to, dust, water, and oil. The outer cover 116 may be transparent or translucent to certain wavelengths of light so that the reflected ranging optical radiation 118 may be received by the optical radiation receiver 106 behind or below the outer cover 116.

[0054] like Figure 1As further shown in FIG. 1 , ranging optical radiation 118 emitted by the optical ranging sensor 102 reflects from the target object 110 and returns to the optical radiation receiver 106 of the optical ranging sensor 102. The target object 110 may be any object, structure, person, entity, or other thing positioned in the line of sight of the ranging optical radiation 118 emitted by the optical ranging sensor 102. In some embodiments, the optical ranging sensor 102 may be configured to determine one or more proximity characteristics of the target object 110, such as the spatial position, motion, and / or velocity of the target object 110. For example, in some embodiments, the optical ranging sensor 102 may be positioned below an electronic display screen of a mobile device and may be configured to detect a target object 110 that is closer than a predetermined threshold of the optical ranging sensor 102. In instances where the target object 110 is closer than the predetermined threshold of the optical ranging sensor 102, the mobile device may deactivate the touch screen, turn off the display screen, or take any other relevant action.

[0055] like Figure 1 As further shown in FIG. 1 , undesired optical noise 120 a-120 e may be received at the optical radiation receiver 106 of the optical ranging sensor 102. The undesired optical noise 120 a-120 e is any optical radiation received at the optical radiation receiver 106 that is not emitted by the optical radiation source 104 or that does not take a direct path from the optical radiation source 104 to the target object 110 and back to the optical radiation receiver 106. For example, Figure 1 As shown in , the undesired optical noise 120a comes from an undesired optical noise source, such as an ambient light source external to the optical ranging sensor 102. The ambient light source may be external light, sunlight, another light source, another illumination source emitting laser and / or pulsed or continuous wave laser, and similar external light sources.

[0056] like Figure 1 As further shown in FIG. 1 , undesirable optical noise 120e may be emitted directly from the optical radiation source 104 to the optical radiation receiver through the internal compartment of the optical ranging sensor. The undesirable optical noise 120e may be due to a gap in the barrier separating the optical radiation source 104 and the optical radiation receiver 106, and / or due to an insufficient barrier separating the optical radiation source 104 and the optical radiation receiver 106. Figure 1 As further shown in , the undesirable optical noise 120b - d may be due to the emitted ranging optical radiation 118 reflecting from various surfaces of the optical ranging sensor 102 and / or the external cover 116 .

[0057] Undesirable optical noise 120a-120e received from undesirable optical radiation sources or from multiple reflections of ranging optical radiation 118 not associated with the target object may reduce the ability of the optical ranging sensor 102 to detect ranging optical radiation 118 reflected from the target object 110. An increase in the undesirable optical noise 120a-120e may cause a decrease in the signal-to-noise ratio (SNR) of the ranging optical radiation 118 reflected from the target object 110. As the SNR decreases due to the undesirable optical noise 120a-120e, the determined proximity characteristics of the target object 110 may become increasingly inaccurate and inconsistent.

[0058] Although Figure 1 1 and 2 as an optical ranging device, but the optical ranging sensor 102 may be any optical sensor configured to emit optical radiation and receive undesired optical radiation at a receiver. For example, the optical ranging sensor 102 may include an optical proximity sensor. In another embodiment, the optical ranging sensor 102 may include an imaging device configured to receive reflected optical radiation.

[0059] Reference now Figure 2A-2B , shows an example assembly of a housing cover 208 including a retroreflective mechanism 230. Figure 2A As shown in FIG, the retroreflective mechanism 230 is positioned on all surfaces of the housing cover 208 before the housing cover 208 is attached to the substrate 212. The surfaces of the housing cover 208 on which the retroreflective mechanism 230 is disposed include a top surface 236, an opening surface 232, a blocking surface 234, an inner surface 238, and an outer surface 240.

[0060] like Figure 2A As shown in FIG. 1 , the housing cover 208 includes a retroreflective mechanism 230. The retroreflective mechanism 230 is any structure, substance, object, frame, or other optical device that reflects directed optical radiation back to the source of the optical radiation with minimal scattering. The retroreflective mechanism 230 may include optical elements and / or reflective surfaces to reflect incident light back at an angle close to the incident angle. In some embodiments, the retroreflective mechanism 230 may include a combination of Fig. 6A The corner retroreflector further described and / or in combination Figure 6BThe cat's eye retroreflector further described. Other retroreflective mechanisms 230 may include retroreflective paint and / or retroreflective tape. The retroreflective mechanism 230 may be applied to the surface of the housing cover 208 as part of the manufacturing process after the housing cover is manufactured but before the housing cover 208 is attached to the substrate 212, and / or after the housing cover 208 is attached to the substrate 212. By applying the retroreflective mechanism 230 to the surface of the housing cover 208, undesirable optical noise that encounters the retroreflective mechanism 230 on the surface of the housing cover 208 will be reflected back toward the source of the undesirable optical noise, for example, the optical radiation source 204, an ambient noise source, or another source of undesirable optical noise.

[0061] like Figure 2A As shown in , the housing cover 208 includes a plurality of inner surfaces 238, an outer surface 240, and an opening surface 232. The inner surface 238 is any surface within the internal cavity formed by the housing cover 208 and adjacent to the internal components of the optical ranging sensor 202 (e.g., the optical radiation source 204, the optical radiation receiver 206). The inner surface 238 includes a blocking surface 234. The blocking surface 234 is any surface of the housing cover 208 on the internal barrier that separates the optical radiation source 204 from the optical radiation receiver 206. In some embodiments, one or more of the inner surfaces 238 may include a retro-reflective mechanism 230. For example, a blocking surface 234 adjacent to the optical radiation source 204 may include a retro-reflective mechanism 230 to prevent unwanted optical noise (such as Figure 1 Undesirable crosstalk optical noise 120 e) shown in FIG. 1 is emitted directly from the optical radiation source 204 to the optical radiation receiver 206 through the internal cavity of the optical ranging sensor 202 .

[0062] The outer surface 240 of the housing cover 208 is any surface outside the interior cavity defined by the housing cover 208. The outer surface 240 includes the top surface 236. The top surface 236 is a surface outside the interior cavity defined by the housing cover 208, including the transmitting opening 226 and the receiving opening 224, and the ranging optical radiation (e.g., as described with respect to Figure 1 The range finding optical radiation 118 described above) is transmitted and received therethrough. In some embodiments, one or more of the exterior surfaces 240 may include a retro-reflective mechanism 230. For example, the top surface 236 may include a retro-reflective mechanism 230 that prevents undesirable optical noise (such as Figure 1 Undesirable crosstalk optical noise 120 b - 120 e ) shown in FIG. 2 is emitted directly from optical radiation source 204 to optical radiation receiver 206 by reflecting from top surface 236 .

[0063] The opening surfaces 232 include any surface of the housing cover 208 that defines an opening in the housing cover 208 that leads to an interior cavity (e.g., the receiving opening 224 and the transmitting opening 226). In some embodiments, one or more of the opening surfaces 232 may include a retro-reflective mechanism 230. For example, the opening surface 232 that defines the receiving opening 224 may include a retro-reflective mechanism 230 that prevents undesirable optical noise (such as Figure 1 Undesirable ambient optical noise 120 a ) shown in FIG. 1 is reflected from the opening surface 232 and transmitted to the optical radiation receiver 206 .

[0064] like Figure 2B As further shown in FIG. 2 , a housing cover 208 including a retro-reflective mechanism 230 is attached to the substrate 212 to form a protective barrier around the optical radiation source 204, the optical radiation receiver 206, and other internal components of the optical ranging sensor 202. In addition, a transmitting optical structure 214 and a receiving optical structure 222 are attached to the housing cover 208 at the transmitting opening 226 and the receiving opening 224, respectively, to further protect the internal components of the optical ranging sensor 202.

[0065] Reference now Figure 3 , an example embodiment of an optical ranging sensor 302 including a retroreflection mechanism 330 is provided. Figure 3 As shown in FIG. 3 , the example optical ranging sensor 302 includes a housing cover 308 attached to a substrate 312, the housing cover 308 defining an internal cavity that includes internal electrical components of the optical ranging sensor 302, such as an optical radiation source 304 and an optical radiation receiver 306. Figure 3 As further shown in FIG. 1 , the housing cover 308 includes an emission opening 326 through which the optical radiation source 304 can emit ranging optical radiation (e.g., Figure 1 In addition, the housing cover 308 includes a receiving opening 324 through which the reflected ranging optical radiation can be received at the optical radiation receiver 306. The example optical ranging sensor 302 also includes a retro-reflective mechanism 330 disposed across a top surface 336 of the housing cover 308.

[0066] In some embodiments, the retroreflective mechanism 330 may be positioned only on selected portions of the housing cover 308 due to manufacturing difficulty, overall cost, or other limiting factors. Figure 3 As shown in FIG, the example retroreflective mechanism 330 is positioned to substantially cover the top surface 336 of the housing cover 308. Figure 1As shown in FIG, the top surface 336 of the housing cover 308 can be a significant source of unwanted optical noise due to crosstalk reflections. A retro-reflective mechanism 330 placed on the top surface 336 of the housing cover 308 redirects the unwanted optical noise toward an optical radiation source, such as optical radiation source 304.

[0067] Reference now Figure 4 , an example embodiment of an optical ranging sensor 402 including a retroreflection mechanism 430 is provided. Figure 4 As shown in FIG. 4 , the example optical ranging sensor 402 includes a housing cover 408 attached to a substrate 412, the housing cover 408 defining an internal cavity that includes internal electrical components of the optical ranging sensor 402, such as an optical radiation source 404 and an optical radiation receiver 406. Figure 4 As further shown in FIG. 4 , the housing cover 408 includes an emission opening 426 through which the optical radiation source 404 can emit ranging optical radiation (e.g., Figure 1 In addition, the housing cover 408 includes a receiving opening 424 through which the reflected ranging optical radiation can be received at the optical radiation receiver 406. The example optical ranging sensor 402 also includes a retro-reflective mechanism 430, which is disposed on a top surface 436 of the housing cover 408 between the transmitting opening 426 and the receiving opening 424.

[0068] As described herein, in some embodiments, the retroreflective mechanism 330 may be positioned on a limited portion of the housing cover 408 due to manufacturing difficulty, overall cost, or other limiting factors. Figure 4 As shown in FIG. 4 , the exemplary retroreflective mechanism 430 is positioned on a top surface 436 of the housing cover 308 between the transmitting opening 426 and the receiving opening 424. Figure 1 As shown in , the top surface 436 of the housing cover 408 located between the transmit opening 426 and the receive opening 424 can be a significant source of undesirable optical noise. For example, optical radiation emitted from the optical radiation source 404 may reflect from multiple surfaces of the housing cover, electronic screen or other external covering, the top surface of the housing cover, and other surfaces. In instances where undesirable optical noise generated due to such crosstalk reflections reaches the optical radiation receiver 406, invalid or inaccurate proximity results may be determined. The retro-reflective mechanism 430 placed on the top surface 436 of the housing cover 408 located between the transmit opening 426 and the receive opening 424 redirects the undesirable optical noise to the optical radiation source, such as the optical radiation source 404.

[0069] Reference now Figure 5 , an example optical ranging system 500 is provided including an optical ranging sensor 502, the optical ranging sensor 502 including a retro-reflective mechanism 530. Figure 5 As shown in FIG. 5 , the optical ranging system 500 includes an optical ranging sensor 502 including an optical radiation source 504 configured to direct ranging optical radiation 518 through an emission opening 526 of a housing cover 508, through an external cover 516 (e.g., a screen), and toward a target object 510. The ranging optical radiation 518 is reflected by the target object 510, returns through a receiving opening 524 in the housing cover 508, and is received at an optical radiation receiver 506. Figure 5 As further shown in FIG. 5 , the optical radiation source 504 and the optical radiation receiver 506 are protected by a housing cover 508 that is attached to the substrate 512 and defines an internal cavity in which the internal electrical components of the optical ranging sensor 502 are disposed. Figure 5 As shown in the figure, the surface of the housing cover 508 includes a retroreflective mechanism 530, which is positioned to redirect optical radiation from various sources of undesirable noise (e.g., undesirable ambient optical noise 520a, undesirable crosstalk optical noise 520b-520e) in a direction at or near the incident angle of the guided optical radiation.

[0070] like Figure 5 As shown in , unwanted noise may enter the optical ranging system 500 from a variety of optical radiation sources. For example, unwanted noise (e.g., unwanted ambient optical noise 520a) may enter the optical ranging system 500 from external sources. In addition, optical radiation emitted from the optical radiation source 504 may reflect from a variety of surfaces of a housing cover, an electronic screen or other external covering 516, or other structures on or near the optical ranging sensor 502 toward the optical radiation receiver 506. Figure 5 As shown in FIG. 5 , the surface of the housing cover 508 includes a retro-reflective mechanism 530. The retro-reflective mechanism 530 redirects incident light in a direction where the incident light encounters the retro-reflective mechanism 530 on the surface of the housing cover 508. Thus, undesirable optical noise 520a-520e is prevented from reflecting toward the optical radiation receiver 506.

[0071] Reference now Fig. 6A , example retroreflective mechanisms (e.g., retroreflective mechanisms 230, 330, 430, 530) are provided. Fig. 6A As shown in , the corner retro-reflector surface 660 can be positioned on one or more surfaces of the housing cover (e.g., housing cover 108, 208, 308, 408, 508) as a retro-reflective mechanism. As shown, the corner retro-reflector 666 includes an array of three mutually perpendicular reflective surfaces 678, which are positioned to form the interior corners of a cube. Incident light 662a, 664a encountering the corner retro-reflector 666 is directed back to the source of the incident light 662a, 664a as retro-reflected light 662b, 664b.

[0072] like Fig. 6A As further shown in FIG. 6 , a plurality of corner retro-reflectors 666 can be positioned in the corner retro-reflector surface 660. The corner retro-reflector surface 660 can be manufactured on one or more surfaces of the housing cover as part of the manufacturing process of the housing cover. In some embodiments, the corner retro-reflectors 666 and / or the corner retro-reflector surface 660 can be deployed on one or more surfaces of the housing cover after the housing cover is manufactured.

[0073] Reference now Figure 6B , example retroreflective mechanisms (e.g., retroreflective mechanisms 230, 330, 430, 530) are provided. Figure 6B As shown in , the cat's eye retro-reflector 674 can be positioned on one or more surfaces of the housing cover (e.g., housing cover 108, 208, 308, 408, 508) as a retro-reflective mechanism. Figure 6B As shown in FIG. 6 , the cat's eye retroreflector 674 generally includes a transparent sphere 672 and a spherical mirror 676. Incident light 668a, 670a entering the cat's eye retroreflector 674 is directed back to the source of the incident light 668a, 670a as retroreflected light 668b, 670b.

[0074] In some embodiments, multiple cat's eye retro-reflectors 674 can be positioned across the surface of the housing cover. The cat's eye retro-reflectors 674 can be manufactured on one or more surfaces of the housing cover as part of the manufacturing process of the housing cover. In some embodiments, the cat's eye retro-reflectors 674 can be deployed on one or more surfaces of the housing cover after the housing cover is manufactured.

[0075] Reference now Figure 7 , provides a number of example electronic systems that are configured to determine the proximity of a target object using an optical ranging sensor 702. Figure 7 As shown in , the housing cover 708 includes a retro-reflective mechanism 730 located on a surface of the housing cover 708. The housing cover 708 is attached to the substrate 712 to form a protective barrier that defines an internal cavity in which the internal electrical components of the optical ranging sensor 702 are disposed. As described herein, the retro-reflective mechanism 730 disposed on one or more surfaces of the housing cover 708 can redirect undesirable optical noise (e.g., undesirable optical noise 120a-120e, 520a-520e) toward the source of the undesirable optical noise. By redirecting the undesirable optical noise in the direction of the source, the undesirable optical noise is redirected away from the optical radiation receiver of the optical ranging sensor 702.

[0076] like Figure 7As further shown in FIG. 7 , a variety of electronic systems (including but not limited to mobile phones 780, wearable devices 782, consumer electronics 784, and industrial electronics 786) can benefit from utilizing an optical ranging sensor 702 according to the embodiments described herein. By reducing the undesired optical noise received at the optical radiation receiver of the optical ranging sensor 702, the SNR of the ranging optical radiation reflected from the target object is increased. The increased SNR improves the accuracy and consistency of the optical ranging sensor 702.

[0077] Although this detailed description has set forth some embodiments of the invention, the appended claims cover other embodiments of the invention that differ from the described embodiments according to various modifications and improvements. For example, those skilled in the art will recognize that these principles can be applied to any electronic device that utilizes a light source to determine the proximity and / or range of a target object. For example, mobile devices such as phones, tablets, and laptops; wearable electronic devices such as watches and earbuds; consumer electronics such as robotic vacuum cleaners and projection systems; industrial electronics such as unmanned aerial vehicles, robots; and the like.

[0078] In the appended claims, unless the specific terms "means for" or "step for" are used in a given claim, it is not intended that the claim be interpreted under 35 USC 112, paragraph 6.

[0079] The use of broader terms such as "comprising," "including," and "having" should be understood to support narrower terms such as "consisting of," "consisting essentially of," and "consisting substantially of." The use of terms such as "optionally," "may," "perhaps," "might," and the like with respect to any element of an embodiment means that the element is not required, or, alternatively, the element is required, both alternatives being within the scope of the embodiment(s). Furthermore, references to examples are provided for illustrative purposes only and are not intended to be exclusive.

Claims

1. An optical ranging sensor configured to determine the proximity of a target object, comprising: Housing cover, including: a launch opening; and Receiving opening; an optical radiation source positioned to direct ranging optical radiation through the emission opening toward the target object; an optical radiation receiver positioned to receive ranging optical radiation reflected from the target object through the receiving opening; and A retroreflective mechanism, implemented on the surface of the housing cover, wherein the retro-reflective mechanism directs the undesirable optical noise back toward a source of the undesirable optical noise and away from an optical radiation receiver; The proximity of the target object is determined based on one or more properties of the ranging optical radiation.

2. The optical ranging sensor of claim 1, wherein the housing cover further comprises a top surface opposite the optical radiation receiver, wherein the retro-reflective mechanism is disposed such that the top surface of the housing cover is substantially covered.

3. The optical ranging sensor of claim 1, wherein a portion of the housing cover between the receiving opening and the transmitting opening includes the retro-reflective mechanism.

4. The optical ranging sensor of claim 1, wherein one or more opening surfaces defining a transmitting opening and a receiving opening include the retro-reflective mechanism.

5. The optical ranging sensor of claim 1, wherein one or more blocking surfaces positioned between the optical radiation source and the optical radiation receiver comprise the retro-reflective mechanism.

6. The optical distance measuring sensor according to claim 1, further comprising: A receiving optical structure is positioned between the optical radiation receiver and the target object, wherein the receiving optical structure is configured to direct the ranging optical radiation toward the optical radiation receiver.

7. The optical distance measuring sensor according to claim 1, further comprising: a transmitting optical structure positioned between a source of optical radiation and a target object, The transmitting optical structure is configured to direct the ranging optical radiation toward the target object.

8. The optical ranging sensor of claim 1, wherein the retroreflective mechanism comprises a corner retroreflector.

9. The optical ranging sensor of claim 1, wherein the retroreflective mechanism comprises a cat's eye retroreflector.

10. The optical ranging sensor of claim 1, wherein the retroreflective mechanism comprises at least one of a retroreflective paint and a retroreflective tape.

11. The optical ranging sensor of claim 1, wherein the one or more properties of the ranging optical radiation include at least one of a time of flight of the optical radiation and an intensity of the optical radiation.

12. The optical ranging sensor of claim 1, wherein the proximity of the target object comprises at least one of a distance of the target object from the optical ranging sensor, a position of the target object relative to the optical ranging sensor, and a speed of the target object.

13. An electronic system configured to determine the proximity of a target object, comprising: External coverings; as well as An optical distance measuring sensor is disposed on the inner side of the outer cover, opposite to the target object, and includes: Housing cover, including: a launch opening; and Receiving opening; an optical radiation source positioned to direct ranging optical radiation through the emission opening toward the target object; an optical radiation receiver positioned to receive ranging optical radiation reflected from the target object through the receiving opening; and A retroreflective mechanism, disposed on the surface of the housing cover, wherein the retro-reflective mechanism directs the undesirable optical noise back toward a source of the undesirable optical noise and away from an optical radiation receiver; The proximity of the target object is determined based on one or more properties of the ranging optical radiation.

14. The electronic system of claim 12, wherein the housing cover further comprises a top surface opposite the optical radiation receiver, wherein the retro-reflective mechanism is disposed such that the top surface of the housing cover is substantially covered.

15. The electronic system of claim 12, wherein a portion of the housing cover between the receiving opening and the transmitting opening includes the retro-reflective mechanism.

16. The electronic system of claim 12, wherein one or more opening surfaces defining the transmitting opening and the receiving opening include the retro-reflective mechanism.

17. The electronic system of claim 12, wherein one or more blocking surfaces positioned between the optical radiation source and the optical radiation receiver comprise the retro-reflective mechanism.

18. The electronic system of claim 12, wherein the retroreflective mechanism comprises at least one of a corner retroreflector and a cat's eye retroreflector.

19. The electronic system of claim 12, wherein the retroreflective mechanism comprises at least one of retroreflective paint and retroreflective tape.

20. The electronic system of claim 12, wherein the proximity of the target object comprises at least one of a distance of the target object from the optical ranging sensor, a position of the target object relative to the optical ranging sensor, and a speed of the target object.

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