Optical sensor and electronic device with the same

An optical sensor and an electronic device having an optical sensor. The optical sensor includes: an optical waveguide containing a photochromic material; a light emitter that emits visible light to be incident on the optical waveguide; and a light receiver that detects the visible light emitted from the light emitter and progressing through the optical waveguide. A transmittance of the optical waveguide in relation to the visible light may be changed by the photochromic material as the optical waveguide is exposed to UV light. The optical sensor and the electronic device having the same may be variously implemented according to exemplary embodiments.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(a) from Korean Application Serial Nos. 10-2014-0004879 and 10-2014-0155422, which were filed in the Korean Intellectual Property Office on Jan. 15, 2014 and Nov. 10, 2014, respectively, the entire content of which is hereby incorporated by reference.

TECHNICAL FIELD

Apparatuses and methods consistent with exemplary embodiments relate generally to a sensor, for example, an optical sensor capable of detecting an amount of ultraviolet (UV) light.

BACKGROUND

UV light having a wavelength of 400 nm or less is divided into various bands based on the wavelength according to a rule of ISO 21348. 98% or more of the UV light reaching the surface of the earth by sunlight is UV light of UV-A region. The UV-A light has a wavelength of 315 nm to 400 nm. The UV-A light has effects on the human skin, and may cause, for example, a skin blackening phenomenon or skin aging. UV light from sunlight having a wavelength of 280 nm to 315 nm is defined as UV light of UV-B region (hereinafter, the UV light may also be referred to as “UV-B light”). About 2% of the UV light reaching the surface of the earth from the sunlight is the UV-B light. The UV-B light may have serious effects on the human body, causing, for example, skin cancer, a cataract, or a red spot phenomenon. Most of the UV-B light is absorbed in the ozone layer. However, the amount of UV-B light reaching the surface of the earth and the UV-B light arriving have increased due to the recent depletion of the ozone layer, thereby raising serious environmental concerns. The UV light of UV-C region (hereinafter, the UV light may also be referred to as “UV-C light) has a wavelength in the range of 100 nm-280 nm. Most of the UV-C light is absorbed in the atmosphere and hardly reaches the surface of the earth. However, the UV-C light reaches the surface of the earth in areas where the ozone layer has depleted, such as the southern hemisphere. The effects of UV light on the human body are variously quantified and a UV index is representative of the quantified ones and is defined as a value obtained by integrating the products of weighted values and UV intensities at respective wavelengths.

Due to the change of atmospheric environment and a cultural expansion of leisure sports, etc., exposure to UV light in everyday life has increased. The UV index keeps the public informed of the danger of exposure to UV light so as to prevent excessive exposure to UV light. When the excessive exposure to UV light is prevented, the public may maintain a healthy life, and an increase of social medical costs may be suppressed.

SUMMARY

In order to calculate a UV index, one or more exemplary embodiments provide a sensor capable of detecting the amount of UV light, for example, an optical sensor. As an optical sensor, a semiconductor type UV sensor based on an inorganic material, such as a silicon carbide (SiC), a gallium nitride (GaN), indium gallium nitride (InGaN), or an aluminum gallium nitride (AlGaN), may be used. The semiconductor type UV sensor may be configured to measure an amount of UV light having a wavelength in a predetermined region according to electric characteristics, such as a band gap, but it is difficult to measure UV light having a wavelength of another region. In addition, since a semiconductor type UV sensor exhibits a serious measurement deviation depending on an incident angle, it has a limit in calculating the correct UV index.

When a wide-angle lens is mounted on an optical sensor, the measurement deviation depending on the incident angle may be reduced. This is because the wide-angle lens mounted on the optical sensor refracts the incident angle so that the incident angle may be reduced. As the refractive index is increased by using the wide-angle lens, the relative sensitivity according to the incident angle may be maintained. However, since the reflectivity on the lens surface is increased, the absolute amount of light incident on the optical sensor may be reduced. In addition, due to the mounting of the wide-angle lens, the size of an electronic device equipped with the optical sensor, for example, an UV index measurement device, may be increased.

Accordingly, aspects of exemplary embodiments provide an optical sensor capable of reducing a measurement deviation of a light amount according to an incident angle, for example, a UV light measurement deviation, and an electronic device including the optical sensor.

In addition, aspects of exemplary embodiments provide an optical sensor that is easy to miniaturize and is capable of reducing a measurement deviation according to an incident angle, and an electronic device including the optical sensor.

According to an aspect of an exemplary embodiment, there is provided an optical sensor including: an optical waveguide containing a photochromic material; a light emitter configured to emit visible light to be incident on the optical waveguide; and a light receiver configured to detect the visible light emitted from the light emitter and progressing through the optical waveguide, wherein a transmittance of the optical waveguide in relation to the visible light may be changed photochromic material as the optical waveguide is exposed to ultraviolet (UV) light.

The photochromic material may include at least one of TiO2and AgCl.

The light emitter may include a Laser Diode (LD), a Vertical Cavity Surface Emitting Laser (VCSEL), or a Light Emitting Diode (LED).

The light receiver may include a Photo Diode (PD).

The optical waveguide may include a light entrance surface provided on one end, and a light emission surface provided on the other end, and the light entrance surface and the light emission surface may be formed to be inclined in relation to a longitudinal direction of the optical waveguide.

The optical sensor may include a substrate having an optical waveguide recess formed on one side thereof, wherein the optical waveguide is formed in the optical waveguide recess.

The light emitter and the light receiver may be disposed on the one side of the substrate, and optical axes of the light emitter and the light receiver may be aligned in the inclined directions in relation to the light entrance surface and the light emission surface, respectively.

The optical sensor may include a substrate, on which each of the light emitter and the light receiver may be mounted, wherein the optical waveguide may be formed to protrude on one side of the substrate, and each of the light emitter and the light receiver may be disposed within the optical waveguide.

The optical sensor may include a light shielding film formed on a surface of the optical waveguide configured to block visible light incident on the light receiver from outside.

The visible light emitted from the light emitter may be reflected by the light shielding film while progressing through the optical waveguide, to be incident on the light receiver.

At least a part of the light shielding film may be removed to expose the optical waveguide to the outside.

The optical sensor may include a cover member disposed to enclose at least a periphery of the optical waveguide, wherein the cover member blocks visible light incident on the light receiver from the outside.

A plurality of light emitters and a plurality of light receivers are provided and at least one of the light emitters and at least one of the light receivers are disposed within an inside of the cover member to correspond with each other.

The optical sensor may include an opening formed on a top of the cover member; and a filter mounted on the opening, wherein the filter transmits UV light having a wavelength which causes a change of color of the photochromic material contained in the optical waveguide and blocks light having other wavelength.

Accordingly, the amount of visible light emitted from the light emitter and detected by the light receiving element may be varied depending on the exposure amount to the UV light. Through this, a UV index may be calculated.

According to an aspect of another exemplary embodiment, an electronic device includes: a cover member configured to transmit light; a light interruption layer formed on the cover member; an opening formed in the light interruption layer; and at least one optical waveguide disposed within the cover member configured to correspond with the opening. The optical waveguide contains a photochromic material so that a transmittance of the optical waveguide in relation to visible light is configured to change when the optical waveguide is exposed to UV light through the opening.

The electronic device may include a light emitter configured to emit visible light to be incident on the optical waveguide; and a light receiver configured to detect the visible light emitted from the light emitter and progressing through the optical waveguide.

The electronic device may include a substrate disposed to face the light interruption layer, wherein the optical waveguide, the light emitter, and the light receiver are disposed on one side of the substrate.

The electronic device may include an optical waveguide recess formed on the one side of the substrate, wherein the optical waveguide is formed in the optical waveguide recess.

The electronic device may include a light entrance surface formed on one end of the optical waveguide; and a light emission surface formed on the other end of the optical waveguide, wherein each of the light entrance surface and the light emission surface is formed to be inclined in relation to a longitudinal direction of the optical waveguide.

The visible light emitted from the light emitter may be reflected or refracted by the light entrance surface to be incident on the optical waveguide, and the visible light progressing through the optical waveguide may be reflected or refracted by the light emission surface to be incident on the light receiver.

According to an aspect of another exemplary embodiment, an optical sensor includes an optical waveguide configured to change its transparency according to a wavelength of external light; a light emitter configured to emit visible light toward a surface of the optical waveguide; and a light receiver configured to detect an amount of the visible light that has passed through the optical wavelength.

The optical waveguide may be disposed in a recessed portion of a substrate.

The optical waveguide may contain a photochromic material.

The optical sensor according to one or more exemplary embodiments may easily calculate a UV index since an optical waveguide containing the photochromic material changes its transmittance depending on the exposure amount to the UV light. In addition, unlike a semiconductor type UV sensor, an optical sensor may reduce the measurement deviation of a light amount according to an incident angle and may be easily miniaturized. Accordingly, it is possible to mount an optical sensor in an electronic device, for example, a mobile communication terminal, a cellphone, a multimedia device, etc. Further, when an optical sensor includes a plurality of optical waveguides, UV indexes of different wavelength bands may be easily calculated according to a component and content of a photochromic material contained in each of the optical waveguides.

DETAILED DESCRIPTION

The exemplary embodiments will be described in detail with reference to the accompanying drawings, but they may be achieved in various forms and are not limited to the following embodiments. However, it should be understood that the present disclosure is not limited to the specific embodiments, but the present disclosure includes all modifications, equivalents, and alternatives within the spirit and the scope of the present disclosure.

Although the terms including an ordinal number such as “first”, “second”, etc., can be used for describing various elements, the structural elements are not restricted by the terms. The terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first structural element may be named a second structural element. Similarly, the second structural element also may be named the first structural element. As used herein, the term “and/or” includes any and all combinations of one or more associated items.

Further, the relative terms “a front surface”, “a rear surface”, “a top surface”, “a bottom surface”, and the like which are described with respect to the orientation in the drawings may be replaced by ordinal numbers such as first and second. In the ordinal numbers such as first and second, their order is determined in the mentioned order, or arbitrarily, and may not be arbitrarily changed if necessary.

In the present disclosure, the terms are used to describe an exemplary embodiment, and are not intended to limit the present disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. In the description, it should be understood that the terms “include” or “have” indicate existence of a feature, a number, a step, an operation, a structural element, parts, or a combination thereof, and do not exclude the existences or probability of addition of one or more another features, numeral, steps, operations, structural elements, parts, or combinations thereof.

In describing exemplary embodiments, terms such as “approximately,” “nearly,” “generally,” and “substantially,” may be used to indicate that a quoted characteristic, parameter, or value does not necessarily have to be exactly correct, and that a permissible error, a measurement error, or a deviation or change including a limit in measurement accuracy and other elements known to a person skilled in the art may be generated to an extent that an effect provided by any features is not excluded.

In the one or more exemplary embodiments, an electronic device may be a random device, and the electronic device may be called a terminal, a portable terminal, a mobile terminal, a communication terminal, a portable communication terminal, a portable mobile terminal, a display device or the like.

For example, the electronic device may be a smartphone, a portable phone, a game player, a TV, a display unit, a heads-up display unit for a vehicle, a notebook computer, a laptop computer, a tablet Personal Computer (PC), a Personal Media Player (PMP), a Personal Digital Assistants (PDA), and the like. The electronic device may be implemented as a portable communication terminal which has a wireless communication function and a pocket size. Further, the electronic device may be a flexible device or a flexible display unit.

The electronic device may communicate with an external electronic device, such as a server or the like, or perform an operation through an interworking with the external electronic device. For example, the electronic device may transmit an image photographed by a camera and/or position information detected by a sensor unit to the server through a network. The network may be a mobile or cellular communication network, a Local Area Network (LAN), a Wireless Local Area Network (WLAN), a Wide Area Network (WAN), an Internet, a Small Area Network (SAN) or the like, but is not limited thereto.

FIG. 1is a view illustrating a configuration of an optical sensor according to an exemplary embodiment.

As illustrated inFIG. 1, an optical sensor10according to an exemplary embodiment may include an optical waveguide13, a light emitting element15, and a light receiving element17, which are disposed on a substrate11.

The optical waveguide13may be formed of an optical fiber in a shape extending in one direction, and may include a photochromic material. The “photochromic material” may be a material which, upon being exposed to light having a specific wavelength, changes its absorbance depending on the wavelength. For example, the photochromic material may have the following properties. The photochromic material may be normally in a transparent state since its absorbance in relation to light in a visible light region is low and upon being exposed to UV light, becomes opaque since its absorbance in relation to light in the visible light region is increased. The photochromic material may contain, for example, compounds, such as 4-tert-butyl-4′-methoxydibenzoylmethane, aberchrome TM540, N-ethoxycinnamate-3′,3′-dimethylspiro(2H-5-nitro-1-benzopyran-2,2′-indoline), diarylethene, 1-phenoxyanthraquinone, 6-NO2BIPS, side-chain polymer liquid crystal (SPLC), bis-spiro[indoline-naphthoxazine](bis-SPO), spirooxazinemoietyanda2-methoxynaphthalenegroup(SPO-NPh), naphthoxazinespiroindoline (NOS), spiropyran, 2′-ethylhexyl-4-methoxy-cinnamate, heterocoerdianthroneendoperoxide (HECDPO), or 1,2-dihetarylethenes, and derivative compounds, silver (Ag), chlorine (Cl), fluorine (F), bromine (Br), iodine (I), and titanium (Ti). As the derivative compounds, diarylethenes, spiropyrans, spirooxazines, chromenes, fulgides and fulgimides, diarylethenes and related compounds, spirodihydroindolizines, azo compounds, polycyclic aromatic compounds, anils and related compounds, polycyclic quinones (periaryloxyquinones), Perimidinespirocyclohexadienones, viologens, and triarylmethanes series derivative compounds may be used. For example, the photochromic material, which may include at least one of a combination of the compounds and derivatives listed above, TiO2, and AgCl, may be included in the optical waveguide. Among products common in everyday life, sunglasses or contact lenses, of which the color is changed depending on a light amount, may contain the photochromic material.

Due to the photochromic material contained therein, the optical waveguide13may change its transmittance in relation to visible light when it is exposed to UV light. Depending on a component and content of the photochromic material, the wavelength band of UV light, which causes the color of the photochromic material to be changed when the UV light is illuminated to the optical waveguide13, may be varied. In addition, depending on the exposure amount of the optical waveguide13to UV light, the transmittance of the optical waveguide13in relation to visible light may be varied.

The light emitting element15is an element that emits visible light to be incident on the optical waveguide13, and may be disposed adjacent to one end of the optical waveguide13. The light emitting element15may include a Laser Diode (LD), a Vertical Cavity Surface Emitting Laser (VCSEL), and a Light Emitting Diode (LED). InFIG. 1, since the light emitting element15is disposed at nearly the same height as the optical waveguide13on the substrate11, the light emitting element may be formed by a side surface light emitting diode. The visible light incident on the optical waveguide13by the light emitting element15progresses through the optical waveguide13.

The light receiving element17is configured to detect the visible light emitted from the light emitting element15and progressing through the optical waveguide13, and may be disposed adjacent to the other end of the optical waveguide13. The light receiving element17may include a Photo Diode (PD).

The output of the visible light by the light emitting element15may be maintained to be nearly constant. However, the amount of visible light detected by the light receiving element17may be varied depending on the transmittance of the optical waveguide13in relation to the visible light. For example, when the optical waveguide13is exposed to UV light, the transmittance of the optical waveguide13in relation to visible light is lowered, and the amount of visible light detected by the light receiving element17may be reduced. When it is desired to calculate the UV index, the UV index may be calculated based on the amount of visible light detected by the light receiving element17. For example, in an environment where the UV index is low, the transmittance of the optical waveguide13in relation to the visible light is increased so that the light receiving element17may detect most of the visible light emitted from the light emitting element15, for example, 90% or more of the visible light. Whereas, in an environment where the UV index is high, the transmittance of the optical waveguide13in relation to the visible light is lowered so that the amount of visible light detected by the light receiving element17may be reduced. Accordingly, the UV index may be calculated based on the amount of visible light detected by the light receiving element17.

The optical sensor10may include a plurality of optical waveguides13, a plurality of light emitting elements15, and a plurality of light receiving elements17. The optical waveguides13may be different from each other in the components and contents of the photochromic materials contained therein. When the components and contents of the photochromic materials contained in the optical waveguides13are different from each other, the transmittances of the optical waveguides13in relation to visible light may be varied by different wavelengths of UV light, respectively. Accordingly, depending on the number of the optical waveguides13, the optical sensor10may calculate respective UV indexes in a plurality of different wavelength regions.

FIG. 2is a view illustrating a configuration of an optical sensor according to another exemplary embodiment.FIGS. 3 and 4are views illustrating operations of the optical sensor according to another exemplary embodiment.

In describing an exemplary embodiment, it is noted that descriptions on the components, which may be easily understood through the preceding exemplary embodiment, may be omitted. For example, detailed descriptions on the components of the photochromic material and the kinds of the light emitting elements and the light receiving elements may be omitted.

As illustrated inFIGS. 2 to 4, the optical sensor20according to an exemplary embodiment may include an optical waveguide recess29formed on one side of the substrate21, and an optical waveguide23may be formed in the optical waveguide recess29. The optical sensor20may include a light emitting element25and a light receiving element27mounted on the one side of the substrate21. A plurality of optical waveguide guides29may be provided on the substrate21, and the optical waveguide23formed in each of the optical waveguide recesses29may contain a photochromic material, of which the component and content may be different from those contained in the optical waveguides formed in the other optical waveguide recesses.

Each optical waveguide23may be provided with a light entrance surface23aand a light emission surface23bon the opposite ends thereof, respectively. The light entrance surface23aand the light emission surface23bmay be disposed to be inclined in relation to the longitudinal direction of the optical waveguide23, for example, in relation to the horizontal direction inFIG. 3. Although being referred to as a “light entrance surface” and “light emission surface” in describing an exemplary embodiment, the visible light does not necessarily have to be incident on the optical waveguide23through the light entrance surface23aor be emitted from the optical waveguide23through the light emission surface23b. For example, the light entrance surface23aand the light emission surface23bmay reflect the visible light as illustrated inFIG. 3, depending on the structure of the optical waveguide23and the arrangement of the light emitting element25and the light receiving element27. In an exemplary embodiment, the visible light may be refracted by the light entrance surface23aand the light emission surface23bto be incident on the optical waveguide23or be emitted from the optical waveguide23.

The light emitting element25and the light receiving element27may be disposed at the positions adjacent to the light entrance surface23aand the light emission surface23b, respectively, so that the optical axes thereof are inclined in relation to the light entrance surface23aand the light emission surface23b, respectively.FIG. 3exemplifies a configuration in which the entrance or emission of visible light is executed on the top side of the optical waveguide23and the visible light is reflected by the light entrance surface23aand the light emission surface23b. For example, the light emitting element25may be implemented by a vertical cavity surface emitting laser diode.

The visible light emitted from the light emitting element25may be incident on one end of the optical waveguide23through the top side, be reflected by the light entrance surface23a, and then progress through the optical waveguide23. When the visible light reaches the other end of the optical waveguide23, the light emission surface23bmay reflect the visible light to be emitted to the top side of the optical waveguide23. The light receiving element27may detect the visible light emitted to the top side of the optical waveguide23from the other end of the optical waveguide23.

Referring toFIG. 4, when the optical waveguide23is exposed to UV light, the transmittance of the optical waveguide23in relation to the visible light may be varied depending on the component of the photochromic material contained in the optical waveguide23and the wavelength of the UV light. As the transmittance of the optical waveguide23in relation to the visible light is changed, the amount of visible light detected by the light receiving element27may be changed. Accordingly, the UV index may be calculated based on the amount of visible light detected by the light receiving element27.

FIG. 5is a perspective view illustrating an electronic device provided with an optical sensor according to an exemplary embodiment.

In describing an exemplary embodiment, descriptions will be made about the electronic device100using a mobile communication terminal as an example, but the present disclosure is not limited thereto.

For example, the electronic device may include at least one of the following: a smart phone, a tablet Personal Computer (PC), a mobile phone, a video phone, an e-book reader, a desktop PC, a laptop PC, a netbook computer, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), an MP3 player, a mobile medical device, a camera, a wearable device (e.g., a Head-Mounted-Device (HMD) such as electronic glasses, electronic clothes, an electronic bracelet, an electronic necklace, an electronic accessory, an electronic tattoo, and a smart watch.

According to an exemplary embodiment, the electronic device may be a smart home appliance provided with a communication function. For example, the smart home appliance may include at least one of the following: a television set, a Digital Video Disk (DVD) player, an audio set, a refrigerator, an air conditioner, a cleaner, an oven, a microwave oven, a washing machine, an air cleaner, a set-top box, a TV box (e.g., Samsung HomeSync™, Apple TV™, or Google TV™), a game consoles, an electronic dictionary, an electronic key, a camcorder, and an electronic picture frame.

According to an exemplary embodiment, the electronic device may include at least one of the following: various medical devices (e.g., a Magnetic Resonance Angiography (MRA), a Magnetic Resonance Imaging (MRI), a Computed Tomography (CT), a movie camera, and an ultrasonic machine), a navigation system, a Global Positioning System (GPS) receiver, an Event Data Recorder (EDR), a Flight Data Recorder (FDR)), an automotive infotainment device, electronic equipment for ships (e.g., marine navigation system and gyrocompass), an avionics, an electronic security device, and an industrial or home robot.

According to an exemplary embodiment, the electronic device may include at least one of the following: a piece of furniture or a part of building/structure including a communication function, an electronic board, an electronic signature receiving device, a projector, various measurement instruments (e.g., measurement instruments of water supply, electricity, gas, electromagnetic waves, etc.). The electronic device may be any one or a combination of two or more of the above-described various devices. In addition, it is apparent to a person skilled in the art that the electronic device according to the present disclosure is not limited to the above-described devices.

Referring toFIG. 5, the electronic device100may include a display device111, a keypad113, and a reception unit115which are provided on the front side of a housing101. The display device111may be configured by a touch screen in which a touch panel is incorporated. The keypad113may be positioned below the display device111, and may include an arrangement of a home button, a menu button, and a back button. On a lateral side of the housing101, a power key117, an ear jack socket119, or the like may be disposed. The position of the power key117, the ear jack socket119, or the like may be variously changed according to the design of the electronic device.

The electronic device100may include various sensors. For example, the electronic device100may include a proximity sensor that detects whether a user's body approaches the electronic device100, an illumination sensor121that automatically adjusts the brightness of the display device111, a geomagnetic sensor/gyro sensor/GPS module which senses a position of the electronic device100and a change thereof, or the like.

The optical sensor20according to an exemplary embodiment may be installed adjacent to the receiving unit115together with the proximity sensor or the illumination sensor121.

Hereinafter, the configuration having the optical sensor20installed in the electronic device100will be described in more detail with reference toFIG. 6.

FIG. 6is a cross-sectional view illustrating the electronic device including the optical sensor according to an exemplary embodiment in a state where the electronic device is partially cut away.

The display device111of the electronic device100may include a cover member111a, a display unit111b, and a light interruption layer111c.

The cover member111amay protect the display unit111band transmit a figure output through the display unit111b. Accordingly, the cover member111amay be made of a transparent material, for example, a synthetic resin, such as transparent acryl. Alternatively, the cover member111amay be made of a glass material. When a touch panel is incorporated in the cover member111a, the display device111may be used as an input device. In assembling the cover member111ato the housing101, the light interruption layer111cmay be formed on the peripheral edge of the cover member111ato conceal an assembly structure or the like. The light interruption layer111cmay be formed by coating a colored paint. An opening111dmay be formed in the light interruption layer111cto expose the optical waveguide23of the optical sensor20.

The substrate21of the optical sensor20may be disposed on the inner surface of the cover member111ato face the light interruption layer111d. The optical waveguide23is positioned to correspond to the opening111d, and the light emitting elements25and the light receiving elements27may be positioned on the light interruption layer111cin the outside of the opening111d. The visible light emitted from the light emitting element25may be reflected or refracted by the light entrance surface23ato progress through the optical waveguide23.

The electronic device100may calculate an UV index through the optical sensor20, and the calculated UV index may be output through the display device111. An application installed in the electronic device100may allow the calculated UV index to be supplied to a service provider so that the service provider may put received UV indexes together and provide various life information items, or the like, including the received UV indexes. An application may allow various life information items to be output to a user through the electronic device100according to information items stored therein and a currently calculated UV index.

FIG. 7is a view illustrating a change of an optical waveguide in an optical sensor according to an exemplary embodiment.FIG. 8is a view illustrating a change of relative absorbance of an optical sensor according to an exemplary embodiment.

As illustrated inFIG. 7, upon being exposed to UV light in a transparent state, an optical waveguide containing a photochromic material is changed to an opaque state, and upon being exposed to visible light or heat, the optical waveguide is changed to the transparent state again. Referring toFIG. 8, the optical sensor containing the photochromic material as described above, for example, the optical waveguide, may have a high relative absorbance UA in relation to UV light and a low relative absorbance in relation to light in the visible light region in the transparent state. When the photochromic material is exposed to the UV light, the relative absorbance VA in relation to light having another wavelength, for example, light in the visible light region, may be increased. Accordingly, when the optical waveguide containing the photochromic material as described above is exposed to UV light, the transmittance in relation to light in the visible light region may be lowered.

More exemplary relative absorbances according to the compositions of photochromic materials are illustrated inFIGS. 9 to 11.

FIG. 9is a view illustrating a change of a relative absorbance of an optical sensor according to an exemplary embodiment in which a benzene series compound is used as the photochromic material of the optical sensor.

A photochromic material made of a benzene series compound may exhibit an increased relative absorbance in relation to light having a wavelength of approximately 700 nm when it is exposed to UV light having a wavelength of approximately 400 nm. Accordingly, a UV light intensity in the UV-A range may be calculated using the benzene series compound as the photochromic material.

FIG. 10is a view illustrating variation of a relative absorbance of an optical sensor according to an exemplary embodiment, in which a spiropyrane series compound is used as the photochromic material of the optical sensor.

A photochromic material made of a spiropyrane series compound may exhibit an increased relative absorbance in relation to light having a wavelength of approximately 630 nm when it is exposed to UV light having a wavelength of approximately 260 nm. Accordingly, a UV light intensity of the mid-ultraviolet (MU-V) region having a wavelength of 200 to 300 nm or the UV-B region may be calculated using the spiropyrane series compound as the photochromic material.

FIG. 11is a view illustrating variation of a relative absorbance of an optical sensor according to an exemplary embodiment in which an acetonitrile (CH3CN) series compound is used as the photochromic material of the optical sensor.

A photochromic material made of an acetonitrile series compound may exhibit an increased relative absorbance in relation to light having a wavelength of approximately 650 nm when it is exposed to UV light having a wavelength of approximately 370 nm. Accordingly, a UV light intensity of the UV-A region may be calculated using the acetonitrile series compound as the photochromic material.

FIGS. 12 to 17are views illustrating exemplary photochromic materials contained in an optical waveguide of an optical sensor according to an exemplary embodiment.

FIG. 12illustrates a structure of a bis-thien-3-yl-perfluorocyclopentene compound,FIG. 13illustrates a structure of a spiro-mero compound,FIG. 14illustrates a structure of a dithienylethene compound,FIG. 15illustrates a structure of an azobenzene compound, andFIGS. 16 and 17illustrates other structures of the dithienylethene compound, respectively.

The relative absorbance in relation to UV light or visible light may be varied depending on a derivative compound bonded to a compound which forms the photochromic materials as described above.

A photochromic material obtained by bonding a CH3derivative compound to the dithienylethene compound illustrated inFIG. 16may exhibit an increased relative absorbance in relation to light having a 662 nm when it is exposed to UV light having a wavelength of 352 nm in the transparent state.

Table 1 represents the kinds of derivative compounds, Rx bonded to the dithienylethene compound, illustrated inFIG. 17, and wavelengths measured when the photochromic materials containing the derivative compounds Rx exhibited a high relative absorbance.

As represented in Table 1, the photochromic materials may exhibit high relative absorbances at different wavelengths depending on the kinds of derivative compounds, even if the compounds forming the photochromic materials are the same. Accordingly, when an optical sensor provided with a plurality of optical waveguides containing photochromic materials having different compositions is used, UV light intensities may be calculated for a plurality of different wavelength bands, respectively.

FIG. 18is a view illustrating a configuration of an optical sensor according to an exemplary embodiment.FIG. 19is a view illustrating an operation of the optical sensor according to an exemplary embodiment.

Referring toFIGS. 18 and 19, the optical sensor30may include a light emitting element35and a receiving element37, each of which is mounted on one side of a substrate31, and an optical waveguide33may be formed to protrude from the one side of the substrate31. Each of the light emitting element35and the light receiving element37may be disposed within the optical waveguide33. The optical waveguide33may contain a photochromic material, for example, a material which exhibits a changed color upon being exposed to light. The photochromic material may exhibit a color which may be changed depending on its composition and a wavelength of light to which it is exposed. As described above, a photochromic material, which exhibits a color changed by UV light, may be contained in the optical waveguide33. When the photochromic material is exposed to UV light, the optical waveguide33may exhibit a changed color so that the transmittance (or absorbance) of the optical waveguide33in relation to visible light may be varied. The light emitting element35emits visible light to the inside of the optical waveguide33, and the light receiving element37may detect the visible light emitted from the light emitting element35. When the transmittance of the optical waveguide33in relation to the visible light is changed, the amount of visible light detected by the light receiving element37is varied. Through this, the optical sensor30may calculate a UV index.

The optical sensor30may further include a light shielding film39aformed on a surface of the optical waveguide33. The light shielding film39amay block other light incident on the light receiving element37from the outside, for example, visible light. In addition, the light shielding film39areflects the light emitted from the light emitting element35so that the light progresses through the inside of the optical waveguide33. For example, the light shielding film39amay allow the light emitted from the light emitting element35to progress through the inside of the optical waveguide33while blocking the external light incident on the optical waveguide33. However, the optical sensor30may include an opening39bformed by removing at least a part of the light shielding film39aso that a part of the optical waveguide33may be exposed to the outside. Light (e.g., UV light) outside of the light shielding film39ais illuminated to a part of the optical waveguide33through the opening39bso that the photochromic material contained in the optical waveguide33may change its color. The position of the opening39bmay be properly set such that the external light incident on the optical waveguide33through the opening39bdoes not reach the light receiving element37.

The light incident on the optical waveguide33through the opening39bcauses the color of the photochromic material to be changed so that a portion P of the optical waveguide33may change the transmittance in relation to visible light. As the transmittance of the portion P of the optical waveguide33in relation to the visible light is changed, the amount of visible light emitted from the light emitting element35and detected by the light receiving element37is changed and the optical sensor30may calculate an UV index based on the change of the visible light detected by the light receiving element37.

FIG. 20is a view illustrating an implemented optical sensor according to an exemplary embodiment.FIG. 21is a cross-sectional view illustrating an optical sensor according to an exemplary embodiment.

Referring toFIGS. 20 and 21, the optical sensor40may include an optical waveguide43formed to protrude on one side of a substrate41, and a light emitting element45and a light receiving element47may be mounted to correspond with each other within the optical waveguide43. The optical sensor40may include a cover member49athat provides the function of the light shielding film. The cover member49amay be mounted on the one side of the substrate41to enclose at least a part of the optical waveguide43. For example, the cover member49amay be mounted to enclose the periphery of the optical waveguide43, and the top of the cover member49amay be opened. A filter49bmay be mounted on the opened top of the cover member49a. The filter49bmay reflect visible light while transmitting UV light. For example, the filter49bmay reflect external visible light not to be incident on the optical waveguide43, and may transmit light (e.g., UV light) having a wavelength which causes the color of the photochromic material contained in the optical waveguide43to be changed. The visible light emitted from the light emitting element45and progressing through the inside of the optical waveguide43may also be reflected by the filter49bto be incident on the light receiving element47. In this manner, the light shielding film and the opening of the preceding exemplary embodiment may be implemented by the cover member49aand the filter49bof an exemplary embodiment.

The light (e.g., UV light) incident on the optical waveguide43through the filter49bcauses the color of the photochromic material to be changed so that the transmittance of at least the portion P of the optical waveguide43in relation to visible light may be changed. The optical sensor40may calculate a UV index based on the change of the transmittance of the optical waveguide43in relation to the visible light. The filter49bmay transmit the light (e.g., UV light) having a wavelength causing the color of the photochromic material contained in the optical waveguide43to be changed and the light having a different wavelength may be blocked by the cover member49aand the filter49b. Accordingly, the light receiving element47may detect the light (e.g., visible light) emitted from the light emitting element45without being affected by the external environment.

FIG. 22is a view illustrating an implemented optical sensor according to an exemplary embodiment.

The optical sensor50according to the present exemplary embodiment is similar to the optical sensor40of the preceding exemplary embodiment but different from the optical sensor40in that a plurality of optical waveguides are disposed on a single substrate. Accordingly, it is noted that in describing the present exemplary embodiment, the same reference numerals will be given to the components, which may be easily understood from the preceding exemplary embodiment, or omitted, and detailed descriptions may also be omitted.

Referring toFIG. 22, the optical sensor50may include one or more optical waveguides43, for example, a pair of optical waveguides43that are disposed on one side of a substrate41to be parallel to each other. Each of the optical waveguides43may accommodate a light emitting element45and a light receiving element47, which may be separated from each other by a cover member49a. The cover member49amay accommodate the optical waveguides43to be separated from each other. A filter49bmay be mounted on the top of the cover member49aso as to transmit only the light (e.g., UV light) having a wavelength which causes the color of the photochromic material contained in each of the optical waveguides43. For example, the filter49bmay only transmit UV light while blocking or reflecting visible light or infrared light. The visible light emitted from each of the light emitting elements45may be blocked or reflected by the cover member49aand the filter49bto progress through the inside of each of the optical waveguides43, thereby being detected by one of the light receiving elements47.

The compositions of the photochromic materials contained in the optical waveguides43may be different from each other. For example, one of the optical waveguides43may contain a photochromic material of which the color is changed by the UV light in the UV-A region and the other one may contain a photochromic material of which the color may be changed by the UV light in the UV-B region. For example, the optical sensor50according to the present exemplary embodiment may calculate a UV index of each of a plurality of wavelength regions.

While the present disclosure has been shown and described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

For example, in the one or more exemplary embodiments, a configuration in which a light emitting element is mounted in an optical sensor itself has been exemplified. However, when the optical sensor is mounted in an electronic device that is provided with a luminance sensor, the light emitting element does not necessarily have to be mounted in the optical sensor. For example, both the luminance sensor and the light receiving element of the optical sensor may detect visible light from sunlight. However, the light receiving element may detect the visible light (visible light from the sunlight) that passes through the optical waveguide containing the photochromic material. Accordingly, the amount of visible light detected by the luminance sensor and the amount of visible light detected by the light receiving element may be compared with each other to calculate the transmittance of the optical waveguide, and a UV index may be calculated based on the transmittance of the optical waveguide.

In addition, although a configuration, in which the optical sensor is disposed on a light interruption layer laterally from a display device, has been exemplified in one or more exemplary embodiments, the optical sensor may be provided on a lateral side or a rear side of the electronic device.