Light source-integrated light sensing system and electronic device including the same

A light sensing system includes a plurality of light-emitting devices arranged to have a first optical axis and a plurality of light-receiving devices arranged to have a second optical axis, the second optical axis being parallel with the first optical axis. The plurality of light-emitting devices and the plurality of light-receiving devices are formed to have a monolithically integrated structure, and the first optical axis and the second optical axis are substantially coaxial to each other, thus improving the efficiency of light reception.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2017-0131654, filed on Oct. 11, 2017, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

Apparatuses consistent with exemplary embodiments relate to a light source-integrated light sensing system and an electronic device including the same.

2. Description of the Related Art

A light detection and ranging (LiDAR) system, used as a sensor or a scanner for detecting an obstacle in various autonomous driving device fields such as smart vehicles, robots, and so forth, will typically include a light source for irradiating laser light onto an object and a sensor for receiving light reflected from the object. Various additional optical parts are disposed on the light path between the light source and the object and the light path between the object and the sensor, making the system bulky and causing a loss of light when the light passes through these optical parts.

SUMMARY

One or more exemplary embodiments may provide a light source-integrated light sensing system capable of improving the efficiency of light reception.

One or more exemplary embodiments may provide a light detection and ranging (LiDAR) device capable of efficiently analyzing an object by including a light sensing system.

According to an aspect of an exemplary embodiment, a light sensing system includes a substrate, a plurality of light-emitting devices disposed on the substrate and arranged to have a first optical axis, and a plurality of light-receiving devices disposed on the substrate and arranged to have a second optical axis that is parallel with the first optical axis.

The first optical axis and the second optical axis may be substantially coaxial to each other.

The plurality of light-emitting devices and the plurality of light-receiving devices may have a monolithically integrated structure.

The plurality of light-emitting devices and the plurality of light-receiving devices may be arranged such that a plurality of light receiving-emitting unit devices including one or more of the plurality of light-emitting devices and one or more of the plurality of light-receiving devices are arranged repeatedly.

Each of the plurality of light receiving-emitting unit devices may have a form in which the a plurality of the light-receiving devices surround the one or more light-emitting devices.

Each of the plurality of light receiving-emitting unit devices may include a light-emitting material layer, which is formed on the substrate and includes a light-emitting region including the one or more light-emitting devices and a non-emitting region including the same material as a material of the one or more light-emitting devices, and the one or more light-receiving devices formed on the non-emitting region.

Each of the plurality of light receiving-emitting unit devices may include a light-receiving material layer, which is formed on the substrate and includes a light-receiving region including the one or more light-receiving devices and a non-receiving region including the same material as a material of the one or more light-receiving devices, and the one or more light-emitting devices formed on the non-receiving region.

The light sensing system may further include a lens structure positioned on the light receiving-emitting unit device to adjust an emitting angle of light emitted from the one or more light-receiving devices.

The lens structure may adjust an incident angle of light toward the one or more light-receiving devices.

The lens structure may have a shape having a different emitting angle depending on a relative position of each of the plurality of light receiving-emitting unit devices.

The light sensing system may further include a support structure having a surface on which the plurality of light receiving-emitting unit devices are arranged, in which a shape of the surface is configured such that a direction of an optical axis of each of the plurality of light receiving-emitting unit devices differs with a position on the surface.

The surface may include a curved surface, or a plurality of inclined surfaces having different angles.

The plurality of light-emitting devices may include a first light-emitting device for emitting light in a first wavelength band and a second light-emitting device for emitting light in a second wavelength band, different from the first wavelength band.

According to an aspect of another exemplary embodiment, a light sensing system includes a plurality of light-emitting devices configured to irradiate light toward an object and a plurality of light-receiving devices configured to receive reflected light of the light irradiated toward the object, in which the plurality of light-emitting devices are arranged to have a first optical axis and the plurality of light-receiving devices are arranged to have a second optical axis, the first optical axis and the second optical axis being parallel to each other, and a processor configured to control the light sensing system and to analyze light received from the light sensing system.

The first optical axis of the plurality of light-emitting devices and the second optical axis of the plurality of light-receiving devices may be substantially coaxial.

The plurality of light-emitting devices and the plurality of light-receiving devices may be formed to have a monolithically integrated structure.

The plurality of light-emitting devices and the plurality of light-receiving devices may be arranged such that a plurality of light receiving-emitting unit devices including one or more of the plurality of light-emitting devices and one or more of the plurality of light-receiving devices are arranged repeatedly.

The processor may be further configured to control the light sensing system such that the plurality of light-emitting devices emit light at different times.

The processor may be further configured to control the light sensing system such that the plurality of light-emitting devices emit light at the same time.

The plurality of light-emitting devices may include a first light-emitting device configured to emit light in a first wavelength band, and a second light-emitting device configured to emit light in a second wavelength band, the second wavelength band being different from the first wavelength band.

The processor may be further configured to control the light sensing system such that the first light-emitting device and the second light-emitting device emit light at different times.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. Throughout the drawings, like reference numerals refer to like elements, and each element may be exaggerated in size for clarity and convenience of a description. Meanwhile, the following exemplary embodiments are merely illustrative, and various modifications may be possible from the exemplary embodiments.

An expression describing a first object or element as “above” or “on” a second object or element may include not only the meaning of the first object or element being disposed immediately on and contacting the second object or element, but also the meaning of the first object or element being disposed on, but not contacting the second object or element.

Terms such as first, second, and the like may be used to describe various elements, but the elements should not be limited to those terms. These terms may be used for the purpose of distinguishing one element from another element.

The singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. If it is assumed that a certain part includes a certain component, the term “including” means that a corresponding component may further include other components unless a specific meaning opposed to the corresponding component is written.

The term used in the exemplary embodiments such as “unit” or “module” indicates a unit for processing at least one function or operation, and may be implemented in hardware, software, or in a combination of hardware and software.

FIG. 1is a conceptual view of a light sensing system according to an exemplary embodiment,FIG. 2is a plan view showing a schematic configuration of the light sensing system ofFIG. 1, andFIG. 3ais a cross-sectional view taken along A-A′ ofFIG. 2to show a detailed configuration of a light receiving-emitting unit device included in the light sensing system ofFIG. 2.

A light sensing system1000is a light source-integrated light receiving system, and is proposed to improve the efficiency of the irradiation of light onto an object OBJ and the reception of light reflected from the object OBJ.

The light sensing system1000includes a plurality of light-emitting devices220and a plurality of light-receiving devices320. The plurality of light-emitting devices220are disposed in an arrangement having a first optical axis OA1and the plurality of light-receiving devices320are disposed in an arrangement having a second optical axis OA2.

InFIG. 1, for convenience of illustration, the first optical axis OA1and the second optical axis OA2are spaced apart from each other, and may be substantially parallel and substantially coaxial.

By arranging the plurality of light-emitting devices220and the plurality of light-receiving devices320such that the first optical axis OA1and the second optical axis OA2are substantially coaxial, the efficiency of light reception is improved. For purposes of this Application, the phrase “substantially coaxial” is not limited to an arrangement in which the first optical axial OA1is completely identical to the second optical axis OA2. The term “substantially coaxial” may also refer to an arrangement, as shown inFIG. 2, in which the first optical axis OA1and the second optical axis OA2are disposed such that the efficiency of light reception is greater than or equal to a predetermined value. The predetermined value may be a value of light reception efficiency of the light sensing system1000, the value being regarded as improved light reception efficiency compared to a system having a light source unit and a light receiver that are separated from each other or a system having different optical axes of the light source unit and the light receiver. Likewise, ‘substantially parallel’ is not limited to a meaning in which the direction of the first optical axis OA1and the direction of the second optical axis OA2are completely parallel to each other, and may include a meaning in which the directions are similar enough to each other to that the efficiency of light reception is greater than or equal to the predetermined value.

As shown inFIG. 2, the arrangement of the plurality of light-emitting devices220and the plurality of light-receiving devices320may have a form in which a plurality of light receiving-emitting unit devices500are repeatedly arranged. The light receiving-emitting unit devices500may each include one or more light-emitting devices220and one or more light-receiving devices320. Although it is illustrated that one light-emitting device220and one light-receiving device320form a single light receiving-emitting unit device500, this illustration is merely an example and the present disclosure is not limited to this illustration.

In this arrangement, the first optical axis OA1, which is a central axis of the arrangement of the plurality of light-emitting devices220, and the second optical axis OA2, which is a central axis of the arrangement of the plurality of light-receiving devices320, may be spaced apart from each other by a distance, having a central axis C of the arrangement of the plurality of light receiving-emitting unit devices500therebetween. Considering such an arrangement, the sentence “the first optical axis OA1and the second optical axis OA2are substantially coaxial to each other” may mean that the spacing distance between the first optical axis OA1and the second optical axis OA2is less than a width of one light receiving-emitting unit device500. However, without being limited to this meaning, even when the spacing distance between the first optical axis OA1and the second optical axis OA2is greater than the width of one light receiving-emitting unit device500, the first optical axis OA1and the second optical axis OA2may be “substantially coaxial” to each other, if the efficiency of light reception is greater than or equal to the predetermined value. Thus, when the spacing distance between the first optical axis OA1and the second optical axis OA2is less than a sum of widths of a plurality of light receiving-emitting unit devices500determined based on the efficiency of light reception, the first optical axis OA1and the second optical axis OA2may be “substantially coaxial” to each other.

To implement the light sensing system1000having such arrangement, the plurality of light-emitting devices220and the plurality of light-receiving devices320may be formed monolithically. The plurality of light-emitting devices220and the plurality of light-receiving devices320may be formed on a single substrate100in such a way to be monolithically integrated. This illustrative structure will be described with reference toFIGS. 3aand3b.

Referring toFIG. 3a, the light sensing system1000may include the substrate100, a light-emitting material layer200formed on the substrate100, and the light-receiving device320formed on regions of the light-emitting material layer200. The light-emitting material layer200includes light-emitting regions EA and non-emitting regions NEA, and the light-emitting regions EA may also be referred to as light-emitting devices220shown inFIG. 2.

The light sensing system1000includes a light receiving-emitting structure formed monolithically. That is, each of the light-emitting devices220and the light-receiving devices320are formed monolithically. Herein, “monolithically” means that the light-emitting device220and the light-receiving device320are not attached by means of coupling by transfer, adhesion, etc., to the substrate. For example, the light-emitting devices220and the light-receiving devices320may be formed directly on the substrate100by a series of sequential processes, e.g., a semiconductor process including deposition, photo-lithography, etching, and so forth, to form monolithically integrated structures on the substrate100.

The light-emitting material layer200may include any of plurality of semiconductor materials, e.g., a III-V group semiconductor compound, a II-VI group semiconductor compound, and a IV-group semiconductor material. The light-emitting material layer200may have a laser structure including a gain layer, a clad layer, and a cavity, and may have, for example, a vertical cavity surface emitting laser (VCSEL) structure. The light-emitting material layer200may be formed on the substrate100by a semiconductor process, and the substrate100may be a semiconductor substrate that is suitable for formation of the semiconductor materials. For example, the substrate100may be a gallium arsenide (GaAs) substrate, a sapphire substrate, an Indium phosphide (InP) substrate, a silicon (Si) substrate, an insulator substrate, or the like. The light-emitting layer200may include aluminum gallium nitride (AlGaN), gallium indium nitride (GaInN), zinc sulfoselenide (ZnSSe), zinc cadmium selenide (ZnCDSe), aluminum gallium indium phosphide (AlGaInP)/GaAs, Ga0.5In0.5P/GaAs, gallium-aluminum-arsenide (GaAlAs)/GaAs, GaAs/GaAs, indium gallium arsenide (InGaAs)/GaAs, indium gallium arsenide phosphide (InGaAsP)/indium phosphide (InP), indium gallium arsenide antimonide (InGaAsSb), plumbum cadmium sulphide (PbCdS), quantum cascade, plumbum sulfoselenide (PbSSe), plumbum stannum telluride (PbSnTe), plumbum stannum selenide (PbSnSe), and the like. For example, AlGaN may be used to generate light having a wavelength band of 350 nm-400 nm. GaInN to generate light having a wavelength band of 375 nm-440 nm, ZnSSe to generate light having a wavelength band of 447 nm-480 nm, ZnCDSe to generate light having a wavelength band of 490 nm-525 nm, AlGaInP/GaAs to generate light having a wavelength band of 620 nm-6800 nm, Ga0.5In0.5P/GaAs to generate light having a wavelength band of 670 nm-680 nm, GaAlAs/GaAs to generate light having a wavelength band of 750 nm-900 nm, GaAs/GaAs to generate light having a wavelength of 904 nm, InGaAs/GaAs to generate light having a wavelength band of 915 nm-1050 nm, InGaAsP/InP to generate light having a wavelength band of 1100 nm-1650 nm, InGaAsSb to generate light having a wavelength band of 2 μm-5 μm, PbCdS to generate light having a wavelength band of 2.7 μm-4.2 μm, a Quantum cascade to generate light having a wavelength band of 3 μm-50 μm, PbSSe to generate light having a wavelength band of 4.2 μm-8 μm, PbSnTe to generate light having a wavelength band of 6.5 μm-30 μm, and PbSnSe to generate light having a wavelength band of 8 μm-30 μm may be used. The light-emitting material layer200may include a plurality of layers in which such materials are formed as a positive (P) type, an intrinsic (I) type, and a negative (N) type. The detailed composition of the semiconductor materials may be determined considering a desired wavelength band of the light L1to be generated and emitted from the light-emitting region EA, i.e., the light-emitting device220. The light-emitting material layer200is illustrated as including three layers, but is not limited to this illustration, and may include three or more layers. The light-emitting material layer200may include a mirror layer for forming a resonant structure. For example, a distributed Bragg reflector (DBR) including pairs, each having two materials having different refractive indices, may be provided to form a resonant cavity. The light-emitting material layer200may include an oxide aperture for controlling a mode or a beam size of oscillating light. The light-emitting material layer200may also include an electrode structure for electric current injection. To reduce a contact resistance with respect to an electrode, the light-emitting material layer200may further include a contact layer doped with P-type and N-type dopants at a high concentration.

The light-emitting material layer200includes the light-emitting region EA and the non-emitting region NEA. The non-emitting region NEA and the light-emitting region EA may include identical semiconductor materials. The light-emitting region EA is capable of emitting light to the outside. However, the entirety of the light-emitting region EA does not necessarily emit light. Rather, and at least a partial region of the light-emitting region EA emits light. The non-emitting region NEA is a region on which the light-receiving device320is formed and light is not emitted therefrom. The light-emitting region EAs and the non-emitting region NEAs may be different from each other in terms of the existence or absence of an electric current injection structure for light emission. For example, each light-emitting region EA may include an electrode (not shown) for electric current injection and the non-emitting regions NEA may not include electrodes. However, without being limited to this example, both the light-emitting regions EA and the non-emitting regions NEA may include similarly-structured electrodes, while the non-emitting regions NEA may be configured such that electric current is not be injected to electrodes of the non-emitting region NEAs—i.e. electrodes of the non-emitting regions NEA may not be connected to an external circuit.

The light-receiving device320formed on the non-emitting region NEA may be integrally formed directly on the light-emitting material layer200. For example, a light-receiving material layer made of a semiconductor material may be formed on the entire surface of the light-emitting material layer200and may be patterned into a predetermined shape by a photo-lithography process, thereby forming the light-receiving device320. The light-receiving device320may include, for example, a III-V group semiconductor compound, a II-VI group semiconductor compound, or a IV group semiconductor compound, and may include a photodiode. The light-receiving device320may include a plurality of layers in which the semiconductor materials are formed as a P type, an I type, and an N type. Although the light-receiving device320is illustrated as including three layers, this illustration is exemplary and the present disclosure is not limited thereto. The light-receiving device320may include not only the semiconductor materials, but also an electrode structure for detecting a light signal as an electric signal.

As stated above, the non-emitting region NEA and the light-emitting region EA are repeated alternately in the light-emitting material layer200, and a unit structure including the light-emitting region EA and the non-emitting region NEA having the light-receiving device320thereon forms the integrated light receiving-emitting unit device500.

FIG. 4ais a cross-sectional view showing an example of a light receiving-emitting unit device included in a light sensing system according to another exemplary embodiment.

A light sensing system1000′ may have the same plan view as the light sensing system1000ofFIG. 2, andFIG. 4aalso corresponds to the cross-sectional view, taken along the line A-A′ ofFIG. 2.

The light sensing system1000′ may include the substrate100, a light-receiving material layer300formed on the substrate100, and a light-emitting device221formed on regions of the light-receiving material layer300. The light-receiving material layer300includes light-receiving regions RA and non-receiving regions NRA, and the light-receiving regions RA may each be referred to as a light-receiving device321.

The light-emitting devices221and the light-receiving devices321are formed directly on the substrate100by a series of sequential processes and each forms a monolithically integrated structure on the substrate100, and a light receiving-emitting unit device501included in the light sensing system1000′ according to the current exemplary embodiment is different from the light receiving-emitting unit device500ofFIGS. 3aand 3bin that the light-emitting device221is disposed on the light-receiving material layer300.

The light-receiving material layer300may be formed on the substrate100by a semiconductor process. The light-receiving material layer300may include, for example, a III-V group semiconductor compound, a II-VI group semiconductor compound, or a IV group semiconductor compound, and may be integrally formed directly on the substrate100. The light-receiving material layer300may be configured to implement one or more photodiodes. The substrate100may be a semiconductor substrate that is suitable for formation of the semiconductor material. For example, the substrate100may be a GaAs substrate, a sapphire substrate, an InP substrate, a Si substrate, an insulator substrate, or the like. Although the light-receiving material layer300is illustrated as including three layers, this illustration is exemplary and the present disclosure is not limited thereto. The light-receiving material layer300may include not only the semiconductor materials, but also an electrode structure for detecting a light signal as an electric signal.

The light-receiving material layer300may include light-receiving regions RA and non-receiving regions NRA. The non-receiving regions NRA and the light-receiving regions RA may include identical semiconductor materials. In the light-receiving material layer300, the light-receiving regions RA are capable of converting light L2incident from the outside into electric signals and outputting the electric signals, and the non-receiving regions NRA are regions on which the light-emitting devices221are formed and which do not output electric signals in response to the light L2incident from the outside. The light-receiving regions RA and the non-receiving regions NRA may be different from each other in terms of the existence or absence of electrode structures for outputting electric signals. For example, the light-receiving regions RA may include electrodes (not shown) for outputting electric signals and the non-receiving regions NRA may not include electrodes. However, without being limited to this example, both the light-receiving regions RA and the non-receiving regions NRA may include electrode structures in the same manner, but electrodes of the non-receiving regions NRA may not be connected with an external circuit in terms of connection with the external circuit.

The light-emitting devices221formed on the non-receiving regions NRA may be monolithically formed directly on the light-receiving material layer300. The light-emitting devices221may be formed on the light-receiving material layer300by a semiconductor process. For example, a light-emitting material layer made of a semiconductor material may be formed on the entire surface of the light-receiving material layer300and may be patterned into a predetermined shape by a photo-lithography process, thereby forming the light-emitting devices221.

The light-emitting devices221may include any of a plurality of semiconductor materials, e.g., a III-V group semiconductor compound, a II-VI group semiconductor compound, and a IV-group semiconductor material. The light-emitting device221may include a plurality of layers in which such materials are of a P type, an N type, and an I type. The light-emitting devices221are illustrated as including three layers, but are not limited to this illustration, and may include three or more layers. The light-emitting devices221may each include a mirror layer for forming a resonant structure, an electrode structure for electric current injection, and a contact layer doped with P-type and N-type dopants at a high concentration to reduce a contact resistance with respect to an electrode. The light-emitting devices221may each have a laser structure and may have, for example, a VCSEL structure.

As stated above, the non-receiving regions NRA and the light-receiving regions RA are repeated alternately in the light-receiving material layer300, and a unit structure including the light-receiving region RA, the non-receiving region NRA, and light-emitting device221on the non-receiving region NRA forms the integrated light receiving-emitting unit device501.

FIG. 5is a plan view showing an example of a light receiving-emitting unit device included in a light sensing system according to another exemplary embodiment.

A light receiving-emitting unit device502may include a light-emitting device222and a plurality of light-receiving devices322surrounding the light-emitting device222. The light-emitting device222may have a circular cross-section, and the plurality of light-receiving devices322may be disposed to surround the light-emitting device222. As is shown, the light-receiving devices322may have a cross-section which surrounds the light-emitting device222and has an approximately rectangular shape that is equally divided into eight parts. However, this illustration is exemplary, and the cross-section of the light-receiving devices322may have a shape that a circular or oval shaped and is equally divided into a plurality of parts.

FIG. 6is a plan view showing another example of a light receiving-emitting unit device included in a light sensing system according to another exemplary embodiment.

A light receiving-emitting unit device503may include a plurality of light-emitting devices223and a plurality of light-receiving devices323surrounding the plurality of light-emitting device223. The plurality of light-emitting devices223have circular cross-sections and are disposed in a central portion, and the plurality of light-receiving devices323have a shape which surrounds the plurality of light-emitting devices223and is an approximately rectangular shape that is equally divided into two parts. However, this illustration is exemplary, and the cross-section of the light-receiving devices323may have a circular or oval shape that is equally divided into two parts.

The cross-sectional shapes of the light receiving-emitting unit devices502and503shown inFIGS. 5 and 6, respectively, may adopt a form in which the light-receiving device320is formed on the light-emitting material layer200or in which the light-emitting device221is formed on the light-receiving material layer300as described with reference to the cross-sectional views ofFIG. 3aor3bor4aor4b.

The shapes illustrated for the light receiving-emitting unit devices502and503intend to describe that the area of the light-receiving region and the area of the light-emitting region may be configured freely depending on a need or convenience in the light sensing systems according to exemplary embodiments, and are not limited to the illustrated shapes.

FIG. 7is a plan view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1001may include a plurality of light-emitting devices224and a plurality of light-receiving devices324which are integrally formed on the substrate100. The plurality of light-emitting devices224and the plurality of light-receiving devices324may have circular cross-sectional shapes. The cross-section of each light-emitting device224may be smaller in size than that of each light-receiving device324, such that each of the plurality of light-emitting devices224may be disposed in a space within an array of four of the plurality of light-receiving devices324, as shown. The plurality of light-emitting devices224are arranged in two directions parallel to the directions of the light-receiving devices324in an alternate manner. Such arrangement may improve the efficiency of light reception by increasing a fill factor of the light-receiving device324.

FIG. 8is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment, andFIG. 10is a cross-sectional view showing a detailed configuration of a light receiving-emitting unit device included in the light sensing system ofFIG. 8.

A light sensing system1002may further include a support structure600for widening a viewing angle, and a plurality of light receiving-emitting unit devices504may be disposed on the support structure600.

Each light receiving-emitting unit device504may include a light-receiving material layer300which is formed on the substrate100and includes light-receiving regions RA and a non-receiving region NRA, and a light-emitting device226formed on the non-receiving region NRA. Each light-receiving region RA is a light-receiving device326. The light receiving-emitting unit device504used in the light sensing system1002according to the current exemplary embodiment is substantially the same as the light receiving-emitting unit device501described with reference toFIGS. 4aand 4bexcept for the number and arrangement of light-receiving devices326forming the unit structure. Materials or structures of the light-receiving material layer300, the light-receiving region RA, the non-receiving region NRA, and the light-emitting device226are substantially the same as described with reference toFIGS. 4aand 4b. The light-receiving material layer300may include the light-receiving regions RA and the non-receiving regions NRA. A unit structure in which two light-receiving regions RA, i.e., two light-receiving devices326, are formed at both sides of a non-receiving region NRA, and the light-emitting device226is formed on the non-receiving region NRA, forms the integrated light receiving-emitting unit device504.

The support structure600includes a surface on which the plurality of light receiving-emitting unit devices504are arranged. The shape of the surface may be set such that an optical axis of each of the plurality of light receiving-emitting unit devices504has a different direction depending on a position on the surface.

For example, the support structure600may have a flat bottom surface and a plurality of inclined surfaces601,602, and603having different angles with respect to the bottom surface. The light receiving-emitting unit devices504disposed on the inclined surfaces601,602, and603, respectively, emit light in different directions according to the angles of the inclined surfaces601,602, and603, such that the viewing angle of the light sensing system1002may be widened. That is, the light sensing system1002may emit the light L1to provide a wide viewing angle and receive the light L2incident at the wide viewing angle.

FIG. 9is a cross-sectional view of a modified light receiving-emitting unit device505which may be provided in the light sensing system1002ofFIG. 8.

The light receiving-emitting unit device505may include a light-emitting material layer200which is formed on the substrate100and includes a light-emitting region EA and non-emitting regions NEA, and light-receiving devices325formed on the non-emitting regions NEA. The light-emitting region EA is a light-emitting device225.

The light receiving-emitting unit device505is substantially the same as the light receiving-emitting unit device500described with reference toFIGS. 3aand 3bexcept for the number and arrangement of light-receiving devices325forming the unit structure. Materials or structures of the light-emitting material layer200, the light-emitting region EA, the non-emitting regions NEA, and the light-receiving devices325are substantially the same as described with reference toFIGS. 3aand 3b. The light-emitting material layer200has the light-emitting region EA and the non-emitting regions NEA. As stated above, a unit structure in which the non-emitting regions NEA are formed at both sides of the light-emitting region EA, that is, the light-emitting device225and the light-receiving devices325are formed on the two non-emitting regions NEA forms the integrated light receiving-emitting unit device505. The light receiving-emitting unit device505may be formed on the support structure600described with reference toFIG. 8, and may implement a wide viewing angle.

FIG. 11is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1004may include a support structure610for widening a viewing angle. The support structure610provided in the light sensing system1004according to the current exemplary embodiment may have a curved surface610aon which the light receiving-emitting unit devices504are disposed. The support structure610may have a shape in which a flat plate is bent as shown inFIG. 11. As the surface610ahas a curved shape, the direction of the light L1emitted from the light receiving-emitting unit device504disposed on the surface610avaries with a position of the light receiving-emitting unit device504, thus emitting the light L1at a wide viewing angle. Likewise, the light L2incident at the wide viewing angle may be received. The curved shape of the support surface610may be formed to form a desired viewing angle by adjusting a degree to which the flat plate is bent.

FIG. 12is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1005may include a plurality of light receiving-emitting unit devices504arranged repeatedly, on each of which a lens structure700for adjusting an emitting angle is further formed. Each light receiving-emitting unit device504will be described as having, but not limited to, the shape illustrated inFIG. 9. The lens structure700may be formed on the light-emitting device226of the light receiving-emitting unit device504. The lens structure700may be formed of a transparent material having a refractive index and the shape of a lens surface, and may adjust the emitting angle of light emitted from the light receiving-emitting unit device504in a desired form.

FIG. 13is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1006according to the current exemplary embodiment is different from the light sensing system1005ofFIG. 12in that a lens structure710adjusts not only the emitting angle of light emitted from the light receiving-emitting unit device504, but also the incident angle of light incident onto the light receiving-emitting unit devices504. The lens structure710may have a form for covering one light receiving-emitting unit device504as a whole, that is, both the light-emitting device226and the two light-receiving devices326.

FIG. 14is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1007according to the current exemplary embodiment is different from the light sensing system1006ofFIG. 13in terms of the shape of a lens structure720. The lens structure720has a form capable of adjusting the emitting angle of light from the light-emitting device226and the incident angle of light to the light-receiving device326.

FIG. 15is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1008according to the current exemplary embodiment is different from the light sensing system1007ofFIG. 14in that a lens structure has a shape for adjusting an emitting angle and an incident angle in different directions depending on a relative position of each of the plurality of light receiving-emitting unit devices504.

With respect to a lens structure731formed on the light receiving-emitting unit device504relatively located in a central portion, shapes of lens structures732and733are determined such that a direction for adjusting an emitting angle and an incident angle is gradually inclined from the center portion to an edge portion. Thus, a wider viewing angle may be implemented.

FIG. 16is a cross-sectional view showing a schematic configuration of a light sensing system according to another exemplary embodiment.

A light sensing system1009according to the current exemplary embodiment is different from the foregoing embodiments in that a lens structure740is formed on a bottom surface of the substrate100.

Although the lens structures740on the bottom surface of the substrate100are illustrated as having identical shapes, the present disclosure is not limited to this example. For example, a lens surface shape may be changed into a shape inclined in a direction with respect to a central axis as described with reference toFIG. 14, or the central axis of the lens surface shape may be gradually inclined from the central portion to the edge portion as described with reference toFIG. 15.

Although the light receiving-emitting unit device504shown inFIGS. 12 through 16is illustrated as having the shape described with reference toFIG. 9, the present disclosure is not limited to this example, and the light receiving-emitting unit device504may be changed to the shape of the light receiving-emitting unit device504described with reference toFIG. 9or to other similar shapes.

The light-emitting devices provided in the light sensing systems according to the foregoing exemplary embodiments may include a plurality of light-emitting devices for emitting light having different wavelengths. For example, a multi-wavelength light sensing system may be implemented, which includes a first light-emitting device for emitting light having a first wavelength band and a second light-emitting device for emitting light having a second wavelength band, the second wavelength band being different from the first wavelength band. The light having different wavelength bands may be formed by adjusting a composition ratio of semiconductor materials of a light-emitting material layer. To form light having different wavelengths, each light receiving-emitting unit device may be configured with a plurality of types and such light receiving-emitting unit devices may be repeatedly arranged in an alternate manner.

The light sensing systems according to the foregoing embodiments may be employed in any of various optical devices and electronic devices.

FIG. 17is a block diagram showing a schematic configuration of a LiDAR device according to an exemplary embodiment.

A LiDAR device5000may include a light sensing system5100and a processor5310that controls the light sensing system5100and analyzes light received from the light sensing system5100.

The light sensing system5100may be any one of the light sensing systems1000,1001,1002,1003,1004,1005,1006,1007,1008, and1009according to the above-described exemplary embodiments, a combination thereof, or a modified form thereof. A light receiving-emitting unit device included in the light sensing system5100may also be any one of the above-described light receiving-emitting unit devices500,501,502,503,504, and505, a combination thereof, or a modified form thereof.

The light sensing system5100is a light sensing system in which a light source is integrated, and includes a plurality of light-emitting devices for irradiating light toward an object OBJ and a plurality of light-receiving devices for receiving reflected light toward the object OBJ, in which the plurality of light-emitting devices are arranged to have the first optical axis OA1, the plurality of light-receiving devices are arranged to have the second optical axis OA2, and the first optical axis OA1and the second optical axis OA2are parallel to each other and may be substantially coaxial to each other. The plurality of light-emitting devices and the plurality of light-receiving devices may have a monolithically integrated structure.

The light-emitting structure provided in the light sensing system5100may generate and emit light to be used for analyzing a position and a shape of the object OBJ. The light-emitting device may generate light having a wavelength band that is suitable for analysis of the position and the shape of the object OBJ, e.g., light having a wavelength in an infrared band. The light-emitting device provided in the light sensing system5100may include a plurality of light-emitting devices for generating light in different wavelength bands. For example, the light sensing system5100may include the first light-emitting device for emitting light in a first wavelength band and the second light-emitting device for emitting light in a second wavelength band, the second wavelength band being different from the first wavelength band. The number of wavelength bands is not limited to this example, and light-emitting devices for generating light having various types of wavelength bands may be included in the light sensing system5100.

The processor5300controls an overall operation of the LiDAR device5000, and may include a light emission controller5310and a light signal analyzer5340.

The light emission controller5310controls light-emitting devices of the light sensing system5100. For example, the light emission controller5310may perform power supply control, on/off control, pulse wave (PW) or continuous wave (CW) generation control, and so forth with respect to the light-emitting device. The light emission controller5310may control the light sensing system5100to cause a plurality of light-emitting devices provided in a plurality of light sensing systems5100to simultaneously emit light (a flash type). The light emission controller5310may control the light sensing system5100such that a plurality of light-emitting devices provided in the light sensing system5100emit light with a time difference therebetween. When the wavelength band of the light sensing system5100is such that a plurality of different types of light-emitting devices are used, for example, the first light-emitting device for emitting light having the first wavelength band and the second light-emitting device for emitting light having the second wavelength band, the light emission controller5310controls the light sensing system5100such that the first light-emitting device and the second light-emitting device emit light at different times. The light emission controller5310controls the light sensing system5100to select and drive a light-emitting device for emitting light having a particular wavelength band from among a plurality of wavelength bands, depending on a desired use.

The light sensing system5100includes an array of light-receiving devices for sensing light reflected from the object OBJ, and thus receives light which is reflected from the object OBJ after being irradiated from the light sensing system5100. The received light signal may be used to analyze existence, a position, a shape, a physical property, etc., of the object OBJ.

The light signal analyzer5340may analyze a light signal received by the light sensing system5100from the object OBJ to analyze the existence, position, shape, physical property, etc., of the object OBJ. The light signal analyzer5340may perform an operation for, for example, time of flight measurement, and identify a three-dimensional (3D) shape of the object OBJ based on the calculation or perform physical property analysis using Raman analysis. The light signal analyzer5340may also analyze a type, an ingredient, a concentration, the physical property, etc., of the object OBJ by using Raman analysis that detects wavelength shift caused by the object OBJ.

The light signal analyzer5340may use any of various operation methods. For example, when a direct time measurement is used pulse light is irradiated to the object OBJ and the time of arrival of the light is measured after being reflected from the object OBJ by using a timer, thus calculating a distance. When a correlation is used, the pulse light is irradiated to the object OBJ and the distance is measured from a brightness of the light reflected from the object OBJ. When a phase delay measurement is used light having a continuous wave, such as a sine wave, is irradiated onto the object OBJ, and a phase difference of the light reflected from the object OBJ is sensed, thus converting the phase difference into the distance.

The LiDAR device5000may include a memory5500in which a program necessary for the operation and other data is stored.

The light signal analyzer5340transmits an operation result, that is, information about the shape, position, and physical property of the object OBJ, to another unit. For example, the information may be transmitted to an autonomous driving device that needs information about a 3D shape, operation, and position of the object OBJ. The information may also be transmitted to a medical equipment using physical property information of the object OBJ, e.g., biometric information. The other unit to which the operation result is transmitted may be a display device or a printer. In addition, the other unit may also be, but not limited to, a smart phone, a cellular phone, a personal digital assistant (PDA), a laptop, a personal computer (PC), and other mobile or non-mobile computing devices.

The LiDAR device5000may be used as a sensor for obtaining 3D information about a front object in real time, thus being applicable to a self-driving device, e.g., a unmanned vehicle, a self-driving vehicle, a robot, a drone, etc., and to a small-size walking means (e.g., a bicycle, a motor cycle, a stroller, a board, etc.), a person and animal assisting means (e.g., a walking stick, a helmet, clothes, accessories, a watch, a bag, etc.), Internet of Things (IoT) devices, building security devices, and so forth.

The above-described light sensing system has a structure in which the light resource unit and the light-receiving unit are integrated, thus simplifying the system.

In the above-described light sensing system, the plurality of light-emitting devices and the plurality of light-receiving devices are arranged such that the optical axis of the light source unit and the optical axis of the light-receiving unit are substantially coaxial to each other, thereby improving the efficiency of light reception.

The above-described light sensing system may be used in any of various optical devices and electronic devices, and may be employed in the LiDAR system to obtain information about the object.

While the light sensing system and the LiDAR device including the same have been shown and described in connection with the exemplary embodiments, it will be apparent to those of ordinary skill in the art that modifications and variations can be made without departing from the spirit and scope of the exemplary embodiments as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative sense rather than a restrictive sense. The range of the exemplary embodiments will be in the appended claims, and all of the differences in the equivalent range thereof should be understood to be included in the exemplary embodiments.