DETECTOR AND MOBILE TERMINAL

A temperature detector configured for use in a mobile terminal includes a lens, a collimator hole, and an infrared sensor that are arranged on an optical path. The lens is configured to converge ambient light, and the ambient light includes target area light and another area light. The collimator hole is used to obtain the target area light by screening and block the other area light. That is, the collimator hole screens the incident ambient light, and allows only the target area light to reach the infrared sensor.

TECHNICAL FIELD

This application relates to the field of imaging technologies, and in particular, to a detector and a mobile terminal.

BACKGROUND

An infrared imaging technology was used for military purpose in earliest time, such as missile guidance and night vision investigation. In recent years, the infrared imaging technology has been gradually deployed into a civil field. For example, an infrared sensor is used in a forehead thermometer for non-contact body temperature measurement. Any object, if not at absolute zero, radiates electromagnetic waves. A shorter wavelength of the radiated electromagnetic waves indicates a higher temperature. When the temperature is higher than 3000 K, the wavelength of the electromagnetic wave is within the visible light wavelength range and is visible to human eyes.

The temperature of a human body ranges from 35° C. to 37° C. (about 300 K Kelvins). The wavelength of a radiated electromagnetic wave from a human body ranges from 8 μm to 12 μm, which is within a far infrared range. Therefore, using an infrared sensor to measure a body temperature means using the sensor to detect infrared light of a wavelength range of 8 μm to 12 μm.

At present, widely used infrared thermometers include forehead thermometers, thermal imagers, and the like. A forehead thermometer uses a thermopile sensor, and usually can measure the temperature of a person within a short distance of 2 cm. There is no lens, and the cost is low. A thermal imager is similar to a camera used for shooting a photo. It is equipped with a precise optical lens and can shoot a clear infrared photo. Another type of an infrared thermometer is a security check gate system. A temperature measurement method used by the security check gate system is similar to that of a thermal imager. Usually, two cameras are installed: one for shooting photos under visible light and the other for shooting photos under infrared light. The photos separately shot under the visible light and the infrared light are later combined according to an AI algorithm and processed using other functions. However, in the conventional technologies, the detection distance of the forehead thermometer is relatively short, and the structure of the thermal imager is relatively complex. As a result, neither the forehead thermometer nor the thermal imager can be integrated into a thin terminal device.

SUMMARY

This application provides a detector and a mobile terminal, to implement long-distance infrared temperature measurement and miniaturize of the detector.

According to a first aspect, a detector is provided. The detector is configured to detect temperature. The detector includes a lens, a collimator hole, and an infrared sensor. The lens, the collimator hole, and the infrared sensor are arranged on an optical path. Light may pass through the lens and the collimator hole and then be irradiated to the infrared sensor. The lens is configured to converge ambient light, and the ambient light includes target area light and light from another area (the other area light). The ambient light, regardless of whether being in a detected area, may be incident into the detector through the lens. The collimator hole is used to obtain the target area light by screening, and block the other area light. To be specific, the collimator hole is used to screen the incident ambient light, and only the target area light is irradiated to the infrared sensor. The infrared sensor is configured to receive the target area light and block the other area light. In the foregoing technical solution, a convergence function of the lens enables the detector to detect a body temperature at a relatively long distance, and the target area is selected through the provided collimator hole. This improves detection accuracy. In addition, the collimator hole is used for screening light. This can decrease the volume of the detector, facilitating miniaturization of the detector.

In a specific implementation solution, a ratio of a diameter of the collimator hole to a diameter of an Airy disk is greater than or equal to 0.5, and less than or equal to 3. This ensures effect of screening infrared light and improves detection effect.

In a specific implementation solution, a distance between the collimator hole and the lens may be greater than, equal to, or less than a focal length of the lens. In this way, different distances need to be set based on a detection requirement.

In a specific implementation solution, the detector further includes a calibration sensor and a controller. The calibration sensor is configured to detect an internal temperature of the detector. The controller is configured to calibrate, based on the detector temperature detected by the calibration sensor, an infrared light temperature detected by the infrared sensor. This improves the detection effect of the detector.

When the infrared sensor and the lens are installed, the infrared sensor and the lens may be matched to each other in different manners. For example, in an optional solution, there are a plurality of infrared sensors, and there are a plurality of lenses. A quantity of lenses is the same as that of infrared sensors, and the lenses are in a one-to-one correspondence with the infrared sensors. Alternatively, there are a plurality of infrared sensors and there is one lens. There are a plurality of collimator holes, and the collimator holes are in a one-to-one correspondence with the infrared sensors.

In an optional solution, when there are a plurality of lenses, a first light blocking layer for isolating light is disposed between any two adjacent lenses. Crosstalk of light is avoided by using the first light blocking layer. This ensures that the light that passes through each lens is not subject to interference.

In an optional solution, when there is one lens, a relative distance between a central axis of the collimator hole and a central axis of the corresponding infrared sensor increases as the distance between the central axis of the corresponding infrared sensor and a central axis of the lens increases. This improves an effect of irradiating the light to the collimator hole.

In an optional solution, a substrate and a package cover are further included. The package cover and the substrate are connected in a sealed manner and enclose a space for accommodating an infrared detector. The substrate and the package cover are used as supporting parts to support the collimator hole and the lens.

In an optional solution, a second light blocking layer is disposed on the package cover, and the collimator hole is provided in the second light blocking layer.

In an optional solution, the lens is a protrusion structure disposed on the package cover. This simplifies the structure of the detector.

In an optional solution, the lens is independently disposed, and the lens may be supported by using a bracket or a housing of a mobile terminal.

In an optional solution, the detector further includes a housing configured to isolate heat from an external environment. The collimator hole and the infrared sensor are located in the housing. This further improves the detection effect.

According to a second aspect, a mobile terminal is provided. The mobile terminal includes a circuit board, and the detector is disposed on the circuit board according to any one of the foregoing embodiments/implementations. The circuit board is electrically connected to an infrared sensor of the detector. In the foregoing technical solution, a convergence function of a lens enables the detector to detect a body temperature at a relatively long distance, and ambient stray light is removed through a collimator hole. This improves detection accuracy. In addition, the collimator hole is used as a structure for screening light. This can decrease a volume of the detector, facilitating miniaturization of the detector.

In an optional solution, when the detector includes a controller, the controller is electrically connected to the circuit board.

DESCRIPTION OF EMBODIMENTS

The following further describes embodiments of this application with reference to the accompanying drawings.

To facilitate understanding of a detector used in embodiments of this application, an application scenario of the detector is first described. The detector provided in embodiments of this application is applied to body temperature detection.FIG.1is a body temperature test scenario. A detector100faces the forehead of a detected person, and detects a body temperature by detecting a forehead temperature of the person. In the conventional technology, a forehead thermometer is usually configured to detect the body temperature. However, a detection distance of the forehead thermometer is relatively short, only 1 cm to 3 cm, and a size of the forehead thermometer is relatively large. An embodiment of this application provides a detector100that have an increased the detection distance. In this way, the forehead temperature can be measured at a distance of 20 cm to 2 m or even at a longer distance. This achieves miniaturization. The following describes the detector in detail with reference to specific accompanying drawings and embodiments.

FIG.2is a block diagram of a structure of a detector according to an embodiment of this application. The detector includes a lens10, a collimator hole20, and an infrared sensor30. The lens10, the collimator hole20, and the infrared sensor30are arranged on an optical path. The collimator hole20is located in the middle. The lens10and the infrared sensor30are located on two sides of the collimator hole20. Light may pass through the lens10and the collimator hole20and then be irradiated to the infrared sensor30. The infrared sensor30may convert an optical signal of received infrared light in the light that passes through the lens10and the collimator hole20into an electrical signal, and determine, based on the electrical signal, a temperature of the received infrared light. A body temperature of a detected person is determined based on the detected temperature of the infrared light.

The lens10is configured to converge ambient light, that is, light outside the detector, into the detector. The lens10may use different types of lenses, provided that light can be converged. For example, the lens10may be different types of lenses, such as a double convex lens, a single convex lens, a triangular prism, and a multilateral prism.

The lens10does not screen light. Ambient light that passes through the lens10includes target area light and another area light. The target area means an area in which the detected person is located for detection. Refer to the application scenario shown inFIG.1. When the detector detects a forehead of a person, the forehead area of the detected person is a target area, and the light emitted from the forehead is the target area light. The other area light means light from an area other than the target area. For example, there are a first detected person and a second detected person during detection. When the first detected person is detected, light sent by a target area of the first detected person is target area light, and infrared light emitted by the second detected person is another area light. Similarly, when the second detected person is detected, infrared light emitted by the first detected person is another area light.

To ensure a detection accuracy, the other area light should not reach the infrared sensor30during detection. Therefore, the collimator hole20is provided on the optical path, so that light in different areas can be selected through the collimator hole20. It can be learned from the structure shown inFIG.2that the collimator hole20and the lens10form a structure similar to a telescope, and a diameter of the lens10is far greater than that of the collimator hole20. Therefore, when the target area light and another area light are irradiated to the collimator hole20, only the target area light can pass through the collimator hole20, and the other area light cannot pass through the collimator hole20.

As an optional solution, when the collimator hole20is used to obtain the target area light by screening, a ratio of a diameter of the collimator hole20to a diameter of an Airy disk is greater than or equal to 0.5, and less than or equal to 3. The Airy disk is a light spot formed at a focal point due to diffraction when a point light source is imaged through limited diffraction. A center of the light spot is a bright round spot, surrounded by a group of weak alternate bright and dark concentric ring strips. The central bright spot bounded by a first dark ring is called the Airy disk.

For example, the ratio of the diameter of the collimator hole20to the diameter of the Airy disk is 0.5, 1, 2, 2.5, 3, or the like. When using the foregoing structure, the collimator hole20may allow only the target area light to pass through and block the other area light.

The infrared sensor30is configured to receive infrared light in the target area light, and detect a temperature based on the infrared light. When the infrared sensor30receives the target area light that passes through the collimator hole20, the target area light includes infrared light and ambient stray light. However, during detection, only the infrared light needs to be detected. Therefore, the infrared sensor30is used as the detector. The infrared sensor30can receive only the infrared light, and does not receive other ambient stray light. This can avoid interference of the ambient stray light. When the infrared light is irradiated to the infrared sensor30, the optical signal may be converted into an electrical signal by the infrared sensor30, and the temperature of the detected person may be determined using the electrical signal.

FIG.3is a schematic diagram of a structure of a detector according to an embodiment of this application. A lens10of the detector may be disposed on a housing or a bracket of a mobile terminal.FIG.3shows an example in which the lens10is disposed on the housing200of the mobile terminal. Ambient light may be incident into the housing200through the lens10.

The detector includes a substrate40and a package cover50. As a supporting structure of an infrared sensor30, the substrate40is configured to hold the infrared sensor30. It should be understood that a circuit layer is disposed on the substrate40, and the infrared sensor30is electrically connected to the circuit layer of the substrate40.

The substrate40is provided with a first groove41used to accommodate the infrared sensor30. The infrared sensor30is disposed in the first groove41, and is fastened to the substrate40by using a cantilever beam42that extends into the first groove41. This substantially reduces contact between the infrared sensor30and another structure, and avoids interference caused by the infrared heat of another structure to the infrared sensor30.

The package cover50covers the substrate40, and the package cover50has a second groove51. The second groove51corresponds to the first groove41, and they together enclose a space to accommodate the infrared sensor30. In this way, the infrared sensor30is not in contact with the substrate40and the package cover50. In addition, the package cover50and the substrate40are connected in a sealed manner. During sealing, the space enclosed by the first groove41and the second groove51is vacuumized to form vacuum packaging. This further reduces interference of convective heat dissipation of the gas in the first groove41and the second groove51with the infrared sensor30. It should be understood that, to ensure that the light that passes through the lens10may be irradiated to the infrared sensor30, the package cover50uses a material that allows infrared light to pass through. For example, the material may be silicon, germanium, ZnS, ZnSe, chalcogenide glass, or the like. The silicon material is used as an example. The silicon itself has a relatively good transmittance in an infrared light range with a wavelength between 8 μm to 10 μm.

As an optional solution, an anti-reflective coating may be added to a surface of the package cover. This improves a transmittance of the package cover, and extends the wavelength of the light that passes through to 8 μm to 12 μm or more.

The package cover50has a first surface. The first surface is a surface that is of the package cover50and that is away from the substrate40. Light is incident from the first surface into the package cover50. A second light blocking layer70is disposed on the first surface. The second light blocking layer70is provided with a first light transmission hole71. The first light transmission hole71is located on an optical path. The light that passes through the lens10may be incident into the package cover50through the first light transmission hole71, and light outside the optical path may be blocked by the second light blocking layer70. In this way, the second light blocking layer70may reduce some ambient stray light that is irradiated onto the infrared sensor30and reduce interference to the infrared sensor30. The second light blocking layer70may be made of a metal material, such as aluminum, nickel, titanium, gold, or copper, or may be made by coating with a light-absorbing material, such as nano carbon black. A diameter of the first light transmission hole71may be greater than, equal to, or less than a diameter of the lens10. This is not specifically limited herein. As an optional solution, the diameter of the first light transmission hole71is slightly less than the diameter of the lens10.

A first light blocking layer80is disposed on a side wall of the second groove51of the package cover50. A collimator hole20is provided in the first light blocking layer80. Light in the package cover50may pass through the collimator hole20and be irradiated onto the infrared sensor30. Target area light is selected through the collimator hole20. Another area light is absorbed or reflected by the first light blocking layer80. For example, the first light blocking layer80may be made of a metal material, such as aluminum, nickel, titanium, gold, or copper, or may be made by coating with a light-absorbing material, such as nano carbon black.

A ratio of the diameter of the collimator hole20to a diameter of an Airy disk is greater than or equal to 0.5, and less than or equal to 3. For example, the ratio of the diameter of the collimator hole20to the diameter of the Airy disk is 0.5, 1, 2, 2.5, 3, or the like. When using the foregoing structure, the collimator hole20allows the target area light to pass through and block the other area light.

As an optional solution, the detector further includes a housing60configured to isolate heat from an external environment. As shown inFIG.3, both the substrate40and the package cover50are located in the housing60. In addition, the collimator hole20and the infrared sensor30are located in the housing60. External heat may be isolated by using the housing60, to reduce an adverse impact of the external heat on the detection result of the infrared sensor30. For example, the housing60may be made of resin, plastic, or another common material with a relatively low thermal conductivity. As an optional solution, an inner side wall of the housing60may be coated with an insulation layer, or the housing60is made of an insulation material. This further improves the insulation effect.

FIG.4is a schematic diagram of an application scenario of a detector according to an embodiment of this application. During use, a lens10faces a detected person. After passing through the lens10, infrared light emitted by the detected person enters an infrared sensor30for detection through a collimator hole20. Although the collimator hole20reduces the amount of the light that enters, a reduction of a spatial sampling size improves resolution of a graph and an image. In addition, the collimator hole20may enable the detector to detect over a longer distance.

FIG.5is a schematic diagram of a structure of a mobile terminal according to an embodiment of this application. A detector is disposed in a housing200of the mobile terminal, for example, affixed to a structure that can support a component, such as a bracket201or a circuit board, in the housing200. It can be seen fromFIG.5that the housing200supports a lens10, and a collimator hole20and an infrared sensor30are located inside the housing. In this way, the detector may be integrated into the mobile terminal within a relatively small size, such as a mobile phone or a tablet computer.

FIG.6is a variant structure based on the detector shown inFIG.3. For some reference numerals inFIG.6, refer to the same reference numerals inFIG.3. Details are not described herein again. A lens10may be integrated into a package cover40. As shown inFIG.6, a part that is of the package cover40and that is exposed in a first light transmission hole71forms an external arc-shaped protrusion structure that faces the package cover40. The arc-shaped protrusion structure is used as the lens10of the detector, so that the structure of the entire detector is more compact.

When the lens10and a collimator hole20are specifically provided, a distance d from the lens10to the collimator hole20may be approximately equal to a focal length f of the lens10. The distance d may be adjusted based on different design objectives. For example, the distance d between the collimator hole20and the lens10may be greater than, equal to, or less than the focal length f of the lens10. The following describes different setups with reference to specific accompanying drawings. It should be understood that straight lines with arrows shown in the accompanying drawings represent light at an edge of a detector's receivable range.

FIG.7is a schematic diagram when d=f. When d=f, a straight light may be received, to obtain a farthest detection distance. However, a detection range of a detector is relatively narrow.

FIG.8is a schematic diagram when d<f. When d<f, an infrared sensor may receive more infrared light to improve a detection rate of a detector. During disposition, a specific field of view of the detector may be designed based on an actual requirement.

FIG.9is a schematic diagram when d>f. When d>f, an infrared sensor can improve resolution of a detector within a specific detection distance range.

FIG.10is another variant structure based on the detector shown inFIG.9. For some reference numerals inFIG.10, refer to the same reference numerals inFIG.9. Details are not described herein again. The detector includes a plurality of infrared sensors, and there are a plurality of corresponding lenses and collimator holes. The plurality of lenses are in a one-to-one correspondence with the plurality of infrared sensors.FIG.10only shows a first infrared sensor31and a second infrared sensor32. On an optical path, a first lens11, a first collimator hole21, and the first infrared sensor31correspond to each other, and a second lens12, a second collimator hole22, and the second infrared sensor32correspond to each other.

As an optional solution, when there are a plurality of lenses, a second light blocking layer70for isolating light is disposed between the plurality of lenses. The second light blocking layer70is disposed on a first surface of a package cover50. When light irradiates onto a lens, crosstalk of light is avoided by using the second light blocking layer70. This ensures that light that passes through each lens is not subject to interference.

It should be understood that detection areas corresponding to the first lens11and the second lens12shown inFIG.10are the same as a detection area of the infrared sensor shown inFIG.9.

A quantity of infrared sensors provided in embodiments of this application is not limited to two as shown inFIG.10. There may alternatively be three, four infrared sensors, or the like. When a plurality of infrared sensors are used, the plurality of infrared sensors may be arranged in an array, and corresponding collimator holes and lenses are also arranged in an array. In addition, a manner of disposing the plurality of infrared sensors shown inFIG.10may also be applied to the structure shown inFIG.3. When a lens uses an independent structure, a corresponding manner of disposing the pluralities of lenses, infrared sensors, and collimator holes may also be used.

FIG.11is a variant structure shown inFIG.10. For some reference numerals inFIG.11, refer to the same reference numerals inFIG.10. In the structure shown inFIG.11, a first infrared sensor31and a second infrared sensor32share a third lens14. A part of light that passes through the third lens14is incident onto the first infrared sensor31through a first collimator hole21, and a part of light is incident onto the second infrared sensor32through a second collimator hole22.

Refer toFIG.11. The first infrared sensor31and the second infrared sensor32are separately arranged on two sides of a central axis L1of the third lens14. A spacing between a central axis H1of the first collimator hole21and a central axis G1of the first infrared sensor31is d1. A spacing between a central axis H2of the second collimator hole22and a central axis G2of the second infrared sensor32is d2. A distance between d1and d2is related to a lens chief ray angle (CRA) that can be received by the first infrared sensor31. The first collimator hole21and the second collimator hole22may be provided based on corresponding lens CRAs that can be received by the first infrared sensor31and the second infrared sensor32. A CRA is a maximum angle of light that can be focused on an infrared sensor from a lens to a side of the infrared sensor.

For ease of understanding a correspondence between an infrared sensor and a corresponding collimator hole, refer to a structure of a detector that uses a plurality of infrared sensors shown inFIG.12.

For some reference numerals inFIG.12, refer to the same reference numerals inFIG.10. In the structure shown inFIG.12, there are a plurality of infrared sensors, and the plurality of infrared sensors are arranged in an array.FIG.12shows an example of a manner of arranging one row of infrared sensors in an array. The one row of infrared sensors includes a first infrared sensor33, a second infrared sensor34, a third infrared sensor35, a fourth infrared sensor36, and a fifth infrared sensor37. The first infrared sensor33to the fifth infrared sensor37share one lens10.

A plurality of collimator holes corresponding to the plurality of foregoing infrared sensors are provided at an offset based on a requirement of a CRA of a corresponding sensor relative to the lens10. For ease of describing a correspondence between a collimator hole and a corresponding infrared sensor, the following introduces a central axis of the lens10, a central axis of each infrared sensor, and a central axis of each collimator hole. The infrared sensor and the corresponding collimator hole meet the following condition: a relative distance between the central axis of the collimator hole and the central axis of the corresponding infrared sensor increases as a distance between the central axis of the corresponding infrared sensor and the central axis of the lens increases.

Refer toFIG.12. A central axis G1of the first infrared sensor33overlaps a central axis L1of the lens10. A pair of the second infrared sensor34and the third infrared sensor35, and a pair of the fourth infrared sensor36and the fifth infrared sensor37are symmetrically arranged on two sides of the first infrared sensor33.

A central axis H1of a first collimator hole23coincides with the central axis G1of the first infrared sensor33and the central axis L1of the lens10. A spacing between a central axis H2of a second collimator hole24and a central axis G2of a second lens10is d1, and a spacing between a central axis H3of a third collimator hole25and a central axis G3of the third infrared sensor35is d2. Correspondingly, a spacing between a central axis H4of a fourth collimator hole26and a central axis G4of the fourth infrared sensor36is d1, and a spacing between a central axis H5of a fifth collimator hole27and a central axis G5of the fifth infrared sensor37is d2. d1and d2need to meet the following condition: d2>d1, to ensure that as a CRA corresponding to a sensor changes, a position of a corresponding collimator hole relative to the infrared sensor also changes. In this way, light that passes through the lens10can be irradiated to the infrared sensor.

FIG.13is a variant structure based on the detector shown inFIG.9. For some reference numerals inFIG.13, refer to the same reference numerals inFIG.3. In addition to the infrared sensor30, the detector further includes a calibration sensor90. The calibration sensor90is configured to detect an internal temperature of the detector. During disposition, the calibration sensor90and the infrared sensor30are disposed in a same or similar manner. A substrate40is fastened to the calibration sensor90by using a cantilever beam, and both the substrate40and a package cover50are provided with a groove that avoids the calibration sensor90. In addition, vacuum packaging is also performed on the calibration sensor90to ensure detection sensitivity. During detection, the calibration sensor90may detect a temperature inside the detector, and more accurately detect a temperature of the calibration sensor90. It can be seen fromFIG.13that the calibration sensor90and the infrared sensor30are in a same environment. Therefore, the temperature detected by the calibration sensor90may also be considered as a temperature of the infrared sensor30.

The detector further includes one controller. The controller is configured to calibrate, based on the detector temperature detected by the calibration sensor90, the infrared light temperature detected by the infrared sensor30. For example, if the temperature detected by the infrared sensor30is T1, and the temperature detected by the calibration sensor90is T2, the controller may obtain, based on the two detected temperatures, a calibrated temperature T0=T1−T2. In this way, the detector can obtain a more accurate temperature.

An embodiment of this application further provides a mobile terminal. The mobile terminal includes a circuit board and a detector disposed on the circuit board according to any one of the foregoing. The circuit board is electrically connected to an infrared sensor of the detector. In addition, when the detector includes a controller, the controller is also electrically connected to the circuit board. In the foregoing technical solution, a convergence function of a lens enables the detector to detect a body temperature over a relatively long distance, and ambient stray light is removed through a collimator hole. This improves detection accuracy. In addition, the collimator hole is used as a structure for screening light. This can reduce the size of the detector, facilitating miniaturization of the detector.

In an optional solution, the mobile terminal further includes a housing. The housing is provided with a light transmission hole. The lens of the detector may be embedded in the light transmission hole. The lens of the detector is supported by the housing. This further reduces the space occupied by the detector in the mobile terminal.

As an optional solution, the detector provided in embodiments of this application may further work with a front-view camera or a rear-view camera of the mobile terminal. Body temperature measurement may be performed when the front-view camera or the rear-view camera is used for taking selfie or taking a portrait picture.

As an optional solution, the detector may further work with AI (artificial intelligence) facial recognition of the mobile terminal. When a user unlocks the mobile terminal through AI facial recognition, the mobile terminal may automatically record monitoring data of the user on personal health and body temperature.

The detector provided in embodiments of this application may be further integrated into a mobile terminal and work with a distance sensor of a mobile phone. During body temperature detection, distance information of the detected person is determined by using the distance sensor, and temperature information of the detected person is detected by using the detector. Temperature measurement data can then be calibrated based on the collected depth information.

In addition, the detector may further be used for CIS (contact image sensor, scanner) design of visible light image/video shooting, to implement a CIS imaging system without a lens.