Optical device using multiple wavelengths of light

Abstract

An optical device using multi-wavelength light includes a substrate and a light emitting array disposed on the substrate and including a plurality of light emitting devices that emit a plurality of lights having different wavelengths. The optical device includes a controller configured to control the light emitting array such that the plurality of lights are differently modulated and emitted simultaneously.

Description

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2019-0037062, filed on March 29, 2019, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to an optical device using multi-wavelength light and a method of operating the same, and more specifically, to an optical device comprising multiple light-emitting devices with different wavelengths and a method of operating the same. Background Technology

[0004] Spectrometers are among the most important optical instruments in the field of optics. Spectrometers of related technologies involve a variety of large and heavy optical components. Recently, with the miniaturization of related applications such as smartphones and wearable devices, there is a need for miniaturized spectrometers.

[0005] This spectrometer can be implemented as a standalone device, or as a component of another device. In particular, research is underway on spectrometers that can be installed in mobile devices such as mobile phones. Summary of the Invention

[0006] An optical device for obtaining the physical properties of a target object and its operation method are provided.

[0007] An optical device and its operation method are also provided for obtaining information about a target object by using multiple light-emitting devices with different wavelengths.

[0008] Additional aspects will be set forth in part in the description which follows, and will become apparent in part from the description itself, or may be learned by practice of the embodiments presented.

[0009] According to an embodiment, an optical device using multi-wavelength light includes: a substrate; and a light-emitting array disposed on the substrate, comprising a plurality of light-emitting devices that emit multiple lights with different wavelengths. The optical device also includes a controller configured to control the light-emitting array such that the multiple lights are modulated differently and emitted simultaneously.

[0010] The controller can also be configured to modulate the waveform of the driving signal applied to the plurality of light-emitting devices, so as to emit a plurality of lights with different waveforms.

[0011] It can modulate any one or any combination of the frequency, amplitude, and phase of the driving signal.

[0012] The waveform of the driving signal can include any one or any combination of sine waves, square waves, triangular waves, and pulse waves.

[0013] A first waveform dependency of first light of the plurality of light emitted from at least two light emitting devices of the plurality of light emitting devices in the light emitting array that are adjacent to each other can be greater than a second waveform dependency of second light of the plurality of light emitted from at least two light emitting devices of the plurality of light emitting devices that are not adjacent to each other.

[0014] A first waveform dependency of first light of the plurality of light emitted from at least two light emitting devices of the plurality of light emitting devices in the light emitting array that are adjacent to each other can be less than a second waveform dependency of second light of the plurality of light emitted from at least two light emitting devices of the plurality of light emitting devices that are not adjacent to each other.

[0015] The plurality of light emitting devices can be arranged two-dimensionally on a substrate.

[0016] The plurality of light emitting devices can be sequentially arranged in a first direction in the light emitting array and emit the plurality of light having sequentially changed wavelengths.

[0017] Each of the plurality of light can have a wavelength band less than about 15 nm.

[0018] A gap between center wavelengths of at least two light of the plurality of light emitted from at least two light emitting devices of the plurality of light emitting devices in the light emitting array that are adjacent to each other can be greater than or equal to about 0.5 nm and less than or equal to about 30 nm.

[0019] Any one or any combination of the plurality of light emitting devices can be a laser or a light emitting diode (LED).

[0020] Any one or any combination of the plurality of light emitting devices can include an active layer disposed on a substrate and configured to generate light, and a wavelength determining layer configured to emit light having one of different wavelengths of the plurality of light among the light generated by the active layer.

[0021] The one of different wavelengths can correspond to any one or both of a thickness and a dielectric constant of the wavelength determining layer.

[0022] The active layer can be disposed in the wavelength determining layer.

[0023] The wavelength determining layer can include a grating pattern structure.

[0024] The wavelength determining layer can include a plurality of dielectric layers spaced apart from each other in a longitudinal direction of the substrate.

[0025] A pitch of the plurality of dielectric layers can continuously vary in the longitudinal direction of the substrate.

[0026] The plurality of dielectric layers can include a first dielectric layer arranged at a first pitch and a second dielectric layer arranged at a second pitch different from the first pitch.

[0027] The light emitting array can include an active layer disposed on the substrate and configured to generate light, and a plurality of wavelength conversion layers disposed on the active layer and configured to emit the light generated by the active layer as a plurality of lights having different wavelengths.

[0028] The optical device can further include a barrier disposed on the active layer and configured to separate the plurality of wavelength conversion layers.

[0029] The optical device can further include a light detector configured to detect light scattered, transmitted, and reflected by at least one of a target object to which the plurality of lights is emitted by the light emitting array, and a processor configured to obtain information about the target object using the light detected by the light detector.

[0030] The light detector can include an image sensor.

[0031] The processor can be further configured to classify the light detected by the light detector with respect to each wavelength of the plurality of lights emitted by the light emitting array, and obtain information about the target object using the light classified with respect to each wavelength.

[0032] According to an embodiment, an operation method of an optical device including a plurality of light emitting devices includes emitting a plurality of lights having different wavelengths and modulations by the plurality of light emitting devices, and detecting light scattered, reflected, and transmitted by at least one of a target object to which the plurality of lights is emitted by the plurality of light emitting devices. The operation method further includes classifying the detected light with respect to each wavelength based on the modulations of the plurality of lights, and obtaining information about the target object using the light classified with respect to each wavelength.

[0033] Each of the plurality of lights can have a wavelength band less than about 15 nm.

[0034] A gap between center wavelengths of at least two of the plurality of lights emitted by at least two of the plurality of light emitting devices adjacent to each other can be greater than or equal to about 0.5 nm and less than or equal to about 30 nm.

[0035] According to an embodiment, an optical device includes a substrate, an active layer disposed on the substrate and configured to generate first light, and a wavelength determination layer disposed on the active layer and including a first portion configured to emit second light having a first wavelength from the first light generated by the active layer and a second portion configured to emit third light having a second wavelength from the first light generated by the active layer.

[0036] The first refractive index of the first portion of the wavelength-determining layer can be different from the second refractive index of the second portion of the wavelength-determining layer.

[0037] The first thickness of the first portion of the wavelength-determining layer can be different from the second thickness of the second portion of the wavelength-determining layer.

[0038] The first portion of the wavelength-determining layer can include first dielectric layers spaced apart from each other in the longitudinal direction of the substrate, the second portion of the wavelength-determining layer can include second dielectric layers spaced apart from each other in the longitudinal direction of the substrate, and a first pitch of the first dielectric layers can be different from a second pitch of the second dielectric layers. BRIEF DESCRIPTION OF DRAWINGS

[0039] The above and other aspects, features, and advantages of embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0040] Figure 1 FIG. 1 is a diagram schematically illustrating an optical device using multi-wavelength light according to an embodiment;

[0041] Figure 2 FIG. 2 is a diagram illustrating an example of a light emitting device according to an embodiment;

[0042] Figure 3 FIG. 3 is a diagram illustrating an example of a light emitting array according to an embodiment, in which the light emitting array emits light having different wavelengths for each effective dielectric constant;

[0043] Figure 4 FIG. 4 is a diagram illustrating an example of a light emitting array according to an embodiment, in which the light emitting array emits different wavelengths of light according to a thickness of a wavelength-determining layer;

[0044] Figure 5 FIG. 5 is a diagram illustrating an example of a light emitting array including different wavelength conversion layers according to an embodiment;

[0045] Figure 6 FIG. 6 is a diagram illustrating an example of a light emitting array including a pattern structure according to an embodiment;

[0046] Figure 7 FIG. 7 is a diagram illustrating an example of a light emitting array including a discontinuous pattern structure according to an embodiment;

[0047] Figure 8 FIG. 8 is a diagram illustrating emission wavelengths of dielectric layers for each pitch according to an embodiment;

[0048] Figure 9 FIG. 9 is a reference diagram for explaining an example of modulating light emitted from a light emitting device according to an embodiment;

[0049] Figure 10 is a graph showing light intensity detected by a light detector for each wavelength according to an embodiment;

[0050] Figure 11 is a graph showing a light detector including a plurality of sub-detectors according to an embodiment; and

[0051] Figure 12 is a flowchart showing an operation method of an optical apparatus according to an embodiment. DETAILED DESCRIPTION

[0052] Reference will now be made in detail embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments can have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are described below, by referring to the drawings, so as to explain various aspects of the present disclosure. Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the elements individually.

[0053] Hereinafter, an optical apparatus using multi-wavelength light and an operation method thereof according to an embodiment will be described with reference to the accompanying drawings. For the sake of clarity and convenience in the description, the width and thickness of layers or regions shown in the drawings can be exaggerated slightly. Like reference numerals refer to like elements throughout the specification.

[0054] As used in the embodiments, terms such as "include," "has," or the like should not be construed as including all components or operations described in the embodiments. It is understood that some of the components or operations can not be included, or other components or operations can be further included.

[0055] Hereinafter, "above" or "on" described can not only include contact and direct above, below, left and right, but also include not contact and direct above, below, left and right. Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings.

[0056] Although the terms "first," "second," and the like can be used in this document to describe various components, the components can not be limited by these terms. These terms are used only to distinguish one component from another component.

[0057] As used herein, the terms "unit," "module," and the like can be understood as a unit processing at least one function or operation, and can be embodied as hardware, software, or a combination thereof.

[0058] Figure 1 is a graph schematically showing an optical apparatus 100 using multi-wavelength light according to an embodiment. As shown in FIG. 1, the optical apparatus 100 can include a light source 110, a light detector 120, and a processor 130. Figure 1As shown, the optical apparatus 100 according to the embodiment can include a light emitting end 120 that emits a plurality of lights having different wavelengths toward a target object 10, a light receiving end 140 that receives lights reflected, scattered, or transmitted through the target object 10 to obtain information about the target object 10, and a controller 160 that controls the light emitting end 120 and the light receiving end 140.

[0059] The light emitting end 120 can include a substrate 121 and a light emitting array 122 integrally disposed on the substrate 121 and including a plurality of light emitting devices 200 that emit lights of different wavelengths.

[0060] The substrate 121 can include a substrate for growing the light emitting devices 200. The substrate 121 can include various materials used in general semiconductor processes. For example, the substrate 121 can include, for example, a silicon substrate or a sapphire substrate. However, this is exemplary, and the substrate 121 can include various other materials.

[0061] The light emitting array 122 can include a plurality of light emitting devices 200 that emit lights of different wavelengths. Each light emitting device 200 can be integrally disposed on the substrate 121. That is, the light emitting devices 200 can be integrally formed with the substrate 121 by lamination or patterning on the substrate 121 via a semiconductor process. The plurality of light emitting devices 200 can be spaced apart in space and disposed on the substrate 121, and some layers can be connected to each other.

[0062] Each light emitting device 200 can emit a light having a narrow wavelength bandwidth, and a spacing between center wavelengths of the light emitting devices 200 can be greater than the wavelength bandwidth. Thus, the light emitted from the light emitting array 122 can be a discontinuous light, such as a comb light. For example, each light emitting device 200 can emit a light having a bandwidth of less than about 15 nm, and the spacing between the center wavelengths can be greater than or equal to about 0.5 nm and less than or equal to about 30 nm.

[0063] Each light emitting device 200 can include a laser or a light emitting diode (LED), and is not limited to a specific example. The light emitting device 200 can be a vertical cavity (C) surface emitting laser diode (VCSEL), a distributed feedback laser, a laser diode, an LED, a resonant cavity LED, etc.

[0064] Alternatively, the light emitting device 200 can include a tunable laser capable of providing lights of different wavelengths. The laser can have a narrow bandwidth and a wide range of wavelength tuning. Then, a single tunable laser can output a plurality of lights having different wavelengths. The tunable laser can output lights of different wavelengths according to an electrical signal, and the tuning of the wavelengths can be continuous or discontinuous. Alternatively, each light emitting device 200 can be an LED having a narrow bandwidth.

[0065] The plurality of light emitting devices 200 can be arranged in one or two dimensions, as shown. Figure 1 The plurality of light emitting devices 200 can be arranged in an m x n matrix, where m and n are natural numbers of 2 or more. The plurality of light emitting devices 200 can be arranged such that the wavelengths sequentially change in one direction. However, the plurality of light emitting devices 200 are not limited thereto.

[0066] Figure 2 is a diagram illustrating an example of a light emitting device 200a according to an embodiment. As shown, Figure 2 the light emitting device 200a can include an active layer 210 that generates light; a first reflective layer 220 and a second reflective layer 230 that are separated from each other with the active layer 210 therebetween to form a resonant cavity C; and a first electrode 240 and a second electrode 250 disposed on the first reflective layer 220 and the second reflective layer 230, respectively. The light emitting device 200a can emit light having a wavelength that resonates in the resonant cavity C, among light generated in the active layer 210.

[0067] The active layer 210 generates light by a driving signal (i.e., an electrical signal) applied to the first electrode 240 and the second electrode 250. The active layer 210 can include a quantum well structure that combines electrons and holes to generate light. The active layer 210 can be made of a III / V compound semiconductor made of Group III and Group V materials. The active layer 210 can include a resonant periodic gain (RPG) structure including a plurality of quantum well layers and a barrier layer between the quantum well layers.

[0068] The quantum well layers and the barrier layer are arranged as a multi-layer structure alternated with each other. Here, as the quantum well layer, a semiconductor material such as InxGa1-xAsyP1-y, InxGa1-xAs, InxGa1-xNyAs1-y, InxGa1-xAsySb (where 0.0 < x < 1.0, 0.0 < y < 1.0), etc. can be used. The values of x and y can be individually selected for each quantum well layer. A quantum dot of In(Ga)(N)As can be used instead of the quantum well layer.

[0069] The first reflective layer 220 and the second reflective layer 230 reflect light generated in the active layer 210 to the resonant cavity C so that the light can resonate in the resonant cavity C. The first reflective layer 220 and the second reflective layer 230 can include a distributed Bragg reflector (DBR) structure designed to have high reflectivity at a resonant wavelength. The first reflective layer 220 and the second reflective layer 230 can have the same reflectivity of about 50%. The first reflective layer 220 and the second reflective layer 230 can include a multi-band distributed Bragg reflector in which, for example, a plurality of different layers are periodically and continuously arranged in a predetermined order. Each of the first reflective layer 220 and the second reflective layer 230 is configured by arranging a high refractive index layer H and a low refractive index layer L in a predetermined order. Here, the high refractive index layer H includes AlxGa1-xAs (0≤x<1), preferably GaAs (i.e., x=0). On the other hand, the low refractive index layer L includes AlyGa1-yAs (0<y≤1), preferably AlAs (i.e., y=1).

[0070] The first electrode 240 can include an n-type doped semiconductor layer, and the second electrode 250 can include a p-type doped semiconductor layer. A driving signal is applied to the first electrode 240 and the second electrode 250 so that the active layer 210 is excited to generate light. The generated light can reciprocate in the active layer 210 while repeatedly reflecting between the first reflective layer 220 and the second reflective layer 230, and light resonating in the resonant cavity C among the amplified light can be emitted to the outside.

[0071] The remaining space of the cavity C can be filled with a material transparent to light emitted from the active layer 210, and can determine the effective dielectric constant of the resonant cavity C, and thus can be referred to as a wavelength-determining layer 260. The active layer 210, as well as the first reflective layer 220 and the second reflective layer 230, can be formed of a material capable of emitting or reflecting light having a relatively wide wavelength. On the other hand, the light emitting device 200a can amplify and emit light having a wavelength of a narrow wavelength band through the resonant condition of the resonant cavity C. The light emitted from the light emitting device 200a can be determined by the resonant wavelength of the resonant cavity C, the resonant wavelength can be determined by the resonant length, and the resonant length can be determined by the width w of the resonant cavity C and the effective dielectric constant of the resonant cavity C, etc. The width of the resonant cavity C can be determined by the thickness of the wavelength-determining layer 260, and the effective dielectric constant in the resonant cavity C can vary depending on the refractive index or the dielectric constant of the wavelength-determining layer 260. Therefore, by changing either or both of the refractive index and the thickness of the wavelength-determining layer 260, the optical path in the resonant cavity C can be changed so that the resonant wavelength can be changed.

[0072] The wavelength-determining layer 260 can include a semiconductor material such as InxGa1-xAsyP1-y, InxGa1-xAs, InxGa1-xNyAs1-y, InxGa1-xAsySb, AlxGa1-xAs, where 0.0 < x < 1.0, 0.0 < y < 1.0.

[0073] Figure 3 is a diagram illustrating a light emitting array 122a as an example of the light emitting array 122 according to an embodiment, in which the light emitting array emits light having different wavelengths for each effective dielectric constant. As shown, the light emitting devices 200 can allow the resonant cavities C to have different effective dielectric constants. For example, the wavelength-determining layers 260a, 260b, and 260c of the respective light emitting devices 200 can include different materials. Accordingly, the wavelengths λ1, λ2, or λ3 of the light emitted from each of the light emitting devices 200 can vary. Figure 3

[0074] The wavelength-determining layers 260a, 260b, and 260c can include a semiconductor material such as InxGa1-xAsyP1-y, InxGa1-xAs, InxGa1-xNyAs1-y, InxGa1-xAsySb, AlxGa1-xAs, where 0.0 < x < 1.0, 0.0 < y < 1.0. The composition ratio of the semiconductor material (e.g., the x value and the y value of InxGa1-xAsyP1-y) can be adjusted to have different refractive indices and dielectric constants.

[0075] Figure 4 is a diagram illustrating a light emitting array 122b as an example of the light emitting array 122 according to an embodiment, in which the light emitting array emits different wavelengths of light according to the length of the resonant cavity C. As shown, Figure 4 the thicknesses of the wavelength-determining layers 260d, 260e, and 260f of the light emitting devices 200 can be different from each other, respectively, such that the resonant wavelengths λ1, λ2, or λ3 can be different. For example, the light emitting devices 200 can be arranged such that the thicknesses of the wavelength-determining layers 260d, 260e, and 260f increase along the first direction X. Then, each of the light emitting devices 200 can emit light having a greater wavelength λ1, λ2, or λ3 in the first direction X.

[0076] The wavelength-determining layers 260d, 260e, and 260f can include a semiconductor material such as InxGa1-xAsyP1-y, InxGa1-xAs, InxGa1-xNyAs1-y, InxGa1-xAsySb, AlxGa1-xAs, where 0.0 < x < 1.0, 0.0 < y < 1.0. The thickness of each of the wavelength-determining layers 260d, 260e, and 260f can be adjusted according to a deposition method. ​

[0077] Figure 5 This is a diagram illustrating an example of a light-emitting array 122c comprising different wavelength conversion layers 270a, 270b, and 270c according to an embodiment. Figure 5 As shown, wavelength conversion layers 270a, 270b, and 270c can also be disposed on the second electrode 250a. Each of the wavelength conversion layers 270a, 270b, and 270c can differently convert the wavelength λ1, λ2, or λ3 of the light resonating in the active layer 210. The materials of the wavelength conversion layers 270a, 270b, and 270c can be different, so that each light-emitting device can emit light with different wavelengths λ1, λ2, or λ3. The wavelength conversion layers 270a, 270b, and 270c can include quantum dots (QDs) of predetermined size and a phosphor layer 292. The quantum dots QDs are excited by light emitted from the active layer 210 and emit light of predetermined wavelengths λ1, λ2, or λ3. The quantum dots QDs can have a core-shell structure including a core portion and a shell portion, or they can have a shell-less microparticle structure. Quantum dot (QD) devices may include any one or any combination of the following: for example, group II-VI semiconductors, group III-V semiconductors, group IV-VI semiconductors, group IV semiconductors, and graphene quantum dots. As an example, quantum dot QD devices may include any one or any combination of Cd, Se, Zn, S, and InP, but are not limited thereto. Wavelength conversion layers 270a, 270b, and 270c may use quantum dots with different emission wavelengths depending on their size or fluorescent layers 292 with different emission wavelengths depending on their material properties.

[0078] Multiple light-emitting devices can be separated by wavelength conversion layers 270a, 270b, and 270c, and can share the active layer 210, the first reflective layer 220 and the second reflective layer 230, the first electrode 240, and the wavelength determination layer 260. Because the resonant cavity C, the active layer 210, the first reflective layer 220 and the second reflective layer 230, the first electrode 240, and the wavelength determination layer 260 are shared, the light-emitting array 122c can be easily fabricated. Furthermore, the light-emitting array 122c may also include barriers 280 separating the light-emitting devices. The barriers 280 can be disposed between the wavelength conversion layers 270a, 270b, and 270c, and can have a mesh structure. The barriers 280 can have a tapered shape that narrows from its upper region to its lower region. The tapered shape of the barriers 280 can increase the discontinuity of the light emitted from the light-emitting device 200 to reduce noise. The barriers 280 can include any one or any combination of a black matrix material, resin, and polymer. The second electrode 250a can also be separated into units based on the light-emitting device.

[0079] exist Figure 5In the embodiment, the wavelengths λ1, λ2, and λ3 of the emitted light vary depending on the materials of the wavelength conversion layers 270a, 270b, and 270c, but are not limited thereto. The wavelengths λ1, λ2, and λ3 of the emitted light can vary by the pattern structure.

[0080] Figure 6 is a diagram illustrating an example of the light emitting array 122d including a pattern structure according to an embodiment. As shown, the light emitting array 122d can include a substrate 121, a wavelength determining layer 290 disposed on the substrate 121, and an active layer 210 disposed on the wavelength determining layer 290. The substrate 121 can include, for example, any one or any combination of quartz, silicon dioxide (SiO2), and sapphire (Al2O3). Figure 6

[0081] The wavelength determining layer 290 can have a grating pattern structure. The wavelength determining layer 290 can include dielectric layers 291 spaced apart and disposed on the substrate 121. Fluorescent layers 292 can be filled between the dielectric layers 291. Accordingly, the dielectric layers 291 and the fluorescent layers 292 can be alternately arranged in the longitudinal direction X of the substrate 121. The dielectric layers 291 can be arranged such that a pitch P of the dielectric layers 291 continuously varies in the longitudinal direction X of the substrate 121.

[0082] The dielectric layers 291 can include, for example, nitride or oxide. The nitride can include, for example, silicon nitride (Si3N4) or gallium nitride (GaN). The oxide can include, for example, any one or any combination of titanium oxide (TiO2), zirconium oxide (ZrO2), and yttrium oxide (Y2O3).

[0083] The fluorescent layers 292 can include, for example, any one or any combination of quantum dots QD, ceramic fluorescent material, and organic dye. The quantum dots QD can include, for example, any one or any combination of cadmium selenide (CdSe), cadmium selenide / zinc sulfide (CdSe / ZnS), cadmium telluride (CdTe), and cadmium sulfide (CdS) as a semiconductor nanoparticle. The ceramic fluorescent material can include, for example, yttrium aluminum garnet (YAG) doped with cerium (Ce). The organic dye can include, for example, rhodamine or fluorescein. In Figure 6 In the embodiment, the fluorescent layers 292 are filled between the dielectric layers 291, but are not limited thereto. The dielectric layers 291 can be filled with a material other than a fluorescent material, for example, a material of the active layer 210.

[0084] ​The active layer 210 generates light by a drive signal (i.e., an electric signal) applied to the electrode pair. The active layer 210 can include a quantum well structure that combines electrons and holes to generate light. The active layer 210 can be made of a III / V compound semiconductor made of Group III and Group V materials. The active layer 210 can include a resonant periodic gain (RPG) structure including a plurality of quantum wells and barrier layers between the quantum wells.

[0085] The quantum well layers and the barrier layers are arranged as a multilayer structure alternated with each other. Here, as the quantum well layers, semiconductor materials such as InxGa1-xAsyP1-y, InxGa1-xAs, InxGa1-xNyAs1-y, InxGa1-xAsySb (where 0.0 < x < 1.0, 0.0 < y < 1.0), etc. can be used. The values of x and y can be individually selected for each quantum well layer. Quantum dots of In(Ga)(N)As can be used instead of the quantum well layers.

[0086] Light among the light generated in the active layer 210 that matches the resonance condition of the wavelength-determining layer 290 can be emitted to the outside. The light emitted from the light emitting array 122d can be determined by the resonance wavelengths λ1, λ2, or λ3 of the wavelength-determining layer 290, and the resonance wavelengths λ1, λ2, or λ3 can be determined by the thickness of the wavelength-determining layer 290, the effective dielectric constant of the wavelength-determining layer 290 (e.g., the refractive index or the dielectric constant of each material (the fluorescent layer 292 and the dielectric layer 291)), the pitch P of the dielectric layer 291, etc. In Figure 6 In this case, the pitch P of the dielectric layer 291 can be arranged to continuously vary in the longitudinal direction X of the substrate 121. Accordingly, the light emitting array 122d can continuously emit light of varying central wavelengths in the longitudinal direction X of the substrate 121.

[0087] Figure 7 is a diagram illustrating an example of a light emitting array 122e including a discontinuous pattern structure according to an embodiment. As Figure 7 indicated, the light emitting array 122e can include a wavelength-determining layer 290 having a discontinuous pattern structure. For example, the wavelength-determining layer 290 can include a first wavelength-determining layer 290a including dielectric layers separated by a first pitch P1, a second wavelength-determining layer 290b including dielectric layers separated by a second pitch P2 different from the first pitch P1, and a third wavelength-determining layer 290c including dielectric layers separated by a third pitch P3 different from the first pitch P1 and the second pitch P2. Accordingly, the first to third wavelength-determining layers 290a, 290b, and 290c can emit light of different wavelengths λ1, λ2, and λ3 to the outside. In Figure 6 and Figure 7In the embodiment, the wavelengths λ1, λ2, and λ3 emitted according to the pitches are different, but are not limited thereto. The thickness or the effective dielectric constant of the wavelength-determining layer 290 can also be adjusted to adjust the wavelengths λ1, λ2, or λ3 of the emitted light.

[0088] Figure 8 is a graph showing the emitted wavelengths of the dielectric layer 291 for each pitch according to the embodiment. As Figure 8 indicated, it can be seen that the center wavelength of the emitted light varies according to the size of the pitch P of the wavelength-determining layer. It can be seen that as the pitch P increases, the center wavelength of the emitted light increases.

[0089] Referring back to Figure 1 , the controller 160 applies a driving signal (e.g., an electrical signal) to each light emitting device 200 so that light is emitted from the light emitting device 200. When the light emitting device 200 emits light, the controller 160 can control the light emitting device 200 to emit light of different modulation. For example, the controller 160 can modulate the light emitted from each light emitting device 200 by differently modulating the waveform of the driving signal applied to each light emitting device 200. Accordingly, each light emitting device 200 can emit light of a different waveform. For example, the waveform of the driving signal can include any one or any combination of a sine wave, a square wave, a triangle wave, a pulse wave, and a sawtooth wave. The controller 160 can modulate the emitted light by modulating the frequency, amplitude, phase, etc. of the driving signal. Even if the waveform is the same, the controller 160 can modulate the light with a driving signal having a different period.

[0090] Figure 9 is a reference diagram for explaining an example of modulating the light emitted from the light emitting device 200 according to the embodiment. Figure 9 Part (a) of Figure 9 is a light signal, and Figure 9 Part (b) of Figure 9 is a modulation signal of a modulation amplitude as a modulation signal applied to the driving signal. When the driving signal including the modulation signal of part (b) is applied to the light emitting device 200, the modulated light signal shown in part (c) of Figure 9 can be output. Accordingly, the controller 160 applies driving signals of different modulation to each light emitting device 200, and thus the light emitting array 122 can output light of different modulation for each wavelength.

[0091] Referring back to Figure 1The controller 160 can control the light emitting devices 200 so that the light emitting devices 200 arranged in one direction emit light having waveforms with sequentially changed degrees of waveform. Accordingly, the light emitted from the light emitting devices 200 adjacent to each other in the light emitting array 122 can have a greater degree of waveform correlation than the light emitted from the light emitting devices 200 not adjacent to each other, but is not limited thereto. The controller 160 can apply a driving signal to the light emitting array 122 so that the light emitted from the light emitting devices 200 adjacent to each other in the light emitting array 122 has a smaller degree of waveform correlation than the light emitted from the light emitting devices 200 not adjacent to each other. Here, the degree of waveform correlation refers to a value indicating whether waveforms are similar. The greater the degree of waveform correlation, the more similar the waveforms.

[0092] The controller 160 can control the light emitting devices 200 included in the light emitting array 122 to emit light simultaneously, but is not limited thereto. The controller 160 can control the light emitting devices 200 to emit light sequentially one by one. Alternatively, the controller 160 can control the light emitting array 122 so that some of the light emitting devices 200 emit light simultaneously, while the remaining light emitting devices 200 emit light sequentially at different times. Alternatively, the light emitting array 122 can be controlled according to the target object 10 so that all of the light emitting devices 200 included in the light emitting array 122 emit light, or only some of the light emitting devices 200 emit light.

[0093] When outputting light of the light emitting array 122, the controller 160 modulates the emitted light by modulating the driving signal into a modulated signal, but is not limited thereto. The light emitting end 120 can further include a separate light modulator, and the controller 160 can modulate the emitted light by controlling the light modulator.

[0094] The light receiving end 140 can include a light detector 141 that detects light incident from the target object 10, and a processor 142 that obtains information about the target object 10 using a result detected by the light detector 141.

[0095] The light detector 141 can detect light incident from the target object 10. The light can be light that has passed through the target object 10, or light scattered or reflected by the target object 10. The light detector 141 can include pixels arranged in two dimensions. Each pixel can receive incident light and convert the light into an electrical signal, and can include a photodetector (e.g., a photodiode) and one or more transistors for activating each photodetector. The light detector 141 can be an image sensor. For example, the light detector 141 can include any one or both of a charge-coupled device (CCD) and a complementary metal-oxide-semiconductor (CMOS).

[0096] The processor 142 can classify the detected intensity of light according to a modulation signal using a Fourier transform. The modulation signal can correspond to the wavelength emitted by the light emitting array 122. Accordingly, the processor 142 can obtain information about the target object 10 by using the detection result classified according to the modulation signal, that is, by using the detection result according to the wavelength. The information about the target object 10 can be physical property information. Herein, the target object 10 can be a person or an animal, but is not limited thereto. The target object 10 can be a part included in the target object 10, or can be an environmental sample for water quality management or soil management, food, or the like.

[0097] Figure 10 is a graph illustrating the intensity of light detected by the light detector 141 for each wavelength according to an embodiment. Even if the light emitting array 122 emits light having the same intensity for each wavelength, the light detector 141 can detect the intensity of light for each wavelength as shown in Figure 10 This is because the target object 10 has different light absorption characteristics for each wavelength. Accordingly, information about the target object 10 can be obtained according to the intensity of light detected for each wavelength.

[0098] Referring back to Figure 1 , the processor 142 can classify the detected intensity of light according to a modulation signal using a Fourier transform, but is not limited thereto. The light detector 141 can be driven by a driving signal corresponding to the driving signal of the light emitting array.

[0099] The light detector 141 can include a plurality of sub-detectors 300 arranged in one dimension or two dimensions.

[0100] Figure 11 is a graph illustrating a light detector 141a including a plurality of sub-detectors 300 according to an embodiment. Each sub-detector 300 can include one or more pixels. The number of sub-detectors 300 can be the same as the number of light emitting devices 200, but is not limited thereto. The number of sub-detectors 300 can be greater than the number of light emitting devices 200.

[0101] Each sub-detector 300 can detect light having a waveform. For example, a first sub-detector 300a can detect first light having a first waveform, a second sub-detector 300b can detect second light having a second waveform, and a third sub-detector 300c can detect third light having a third waveform. As described above, the waveform of light detected by each sub-detector 300 can be determined by a driving signal applied to each sub-detector 300.

[0102] The controller 160 can control the light detector 141 so that the light detector 141 can detect light. The controller 160 can drive the light detector 141 in units of the sub-detector 300 and can drive the light detector 141 through a driving signal corresponding to a driving signal for driving the light emitting array 122. For example, when the optical driver drives the first light emitting device through a first driving signal having a first waveform, the controller 160 can drive the first sub-detector 300a corresponding to the first light emitting device through a second driving signal corresponding to the first driving signal. Since the first driving signal and the second driving signal are the same or very similar, the first driving signal and the second driving signal can be coupled. The second driving signal of the first sub-detector 300a can be coupled to light generated by the first driving signal to detect light. Accordingly, each sub-detector 300 can detect light of a driving signal for each waveform. By detecting light of one wavelength through coupling as described above, noise can be easily removed by external light or light having a different wavelength. A band pass filter for detecting light of one wavelength is fixed during a manufacturing process, while a driving signal applied to the light detector 141 is easily controlled by the controller 160, and the waveform of the driving signal is also changed for each sub-detector 300. The same wavelength of light can be detected by various more sub-detectors 300.

[0103] The optical device as described above can spatially separate and emit a plurality of lights having different wavelengths and modulations. Since the optical device separates a detection result for each wavelength based on modulation, it is not necessary to have a hardware filter for detecting a wavelength.

[0104] Figure 12 FIG. 13 is a flowchart illustrating an operation method of an optical device according to an embodiment.

[0105] In operation S1210, the light emitting end 120 can emit a plurality of lights having different wavelengths and modulations. The light emitting end 120 can include a substrate 121 and a plurality of light emitting devices 200 integrally disposed on the substrate 121 and emitting light having different wavelengths. Each light emitting device 200 can include a laser or an LED, and is not limited to a specific example.

[0106] Each light emitting device 200 of the light emitting array 122 can emit light having a narrow wavelength bandwidth, and an interval between center wavelengths of the light emitting devices 200 can be greater than the wavelength bandwidth. Accordingly, light emitted from the light emitting array 122 can be discontinuous light, such as comb light. For example, each light emitting device 200 can emit light having a bandwidth of less than about 15 nm, and an interval between center wavelengths can be greater than or equal to about 0.5 nm and less than or equal to about 30 nm.

[0107] The controller 160 applies a driving signal (e.g., an electrical signal) to each light emitting device 200 so that light is emitted from the light emitting device 200. When the light emitting device 200 emits light, the controller 160 can control the light emitting device 200 to emit light modulated differently. For example, the controller 160 can modulate the light emitted from each light emitting device 200 by modulating the waveform of the driving signal applied to each light emitting device 200 differently. Accordingly, each light emitting device 200 can emit light of a different waveform. For example, the waveform of the driving signal can include any one or any combination of a sine wave, a square wave, a triangle wave, a pulse wave, and a sawtooth wave. The controller 160 can modulate the emitted light by modulating the frequency, amplitude, phase, etc. of the driving signal. Even if the waveform is the same, the controller 160 can modulate the light with a driving signal having a different period.

[0108] The controller 160 can control the light emitting devices 200 included in the light emitting array 122 to emit light simultaneously, but is not limited thereto. The controller 160 can control the light emitting devices 200 to emit light sequentially one by one. Alternatively, the controller 160 can control the light emitting array 122 so that some light emitting devices 200 emit light simultaneously while the remaining light emitting devices 200 emit light sequentially at different times. Alternatively, the light emitting array 122 can be controlled according to the target object 10 so that all of the light emitting devices 200 included in the light emitting array 122 emit light or only some of the light emitting devices 200 emit light.

[0109] When outputting light of the light emitting array 122, the controller 160 modulates the emitted light by modulating the driving signal into a modulated signal, but is not limited thereto. The light emission end 120 can further include a separate light modulator, and the controller 160 can modulate the emitted light by controlling the light modulator.

[0110] In operation S1220, the light detector 141 of the light reception end 140 can detect light incident from the target object 10. The light can be light that has passed through the target object 10 or light scattered or reflected by the target object 10. The light detector 141 can include pixels arranged two-dimensionally. Each pixel can receive incident light and convert the light into an electrical signal, and can include a photodetector (e.g., a photodiode) and one or more transistors for activating each photodetector. The light detector 141 can be an image sensor. For example, the light detector 141 can include any one or both of a charge-coupled device (CCD) and a complementary metal-oxide-semiconductor (CMOS).

[0111] The processor 142 can classify the detection results for each wavelength based on the modulation in operation S1230. For example, the processor 142 can classify the intensity of the detected light using a Fourier transform according to a modulation signal. The modulation signal can correspond one-to-one to the wavelengths emitted by the light emitting array. Accordingly, the processor 142 can classify the detection results for each wavelength based on the modulation signal.

[0112] Alternatively, the light detector 141 can detect light of each wavelength based on modulation. The light detector 141 can include sub-detectors 300 arranged in one or two dimensions. Each sub-detector 300 can detect light having one wavelength. The controller 160 can drive the light detector 141 in units of the sub-detector 300 and can drive the light detector 141 by a driving signal corresponding to a driving signal for driving the light emitting array 122. For example, when the optical driver drives a first light emitting device by a first driving signal having a first wavelength, the controller 160 can drive a first sub-detector 300a corresponding to the first light emitting device by a second driving signal corresponding to the first driving signal. Since the first driving signal and the second driving signal are identical or very similar, the first driving signal and the second driving signal can be coupled. The second driving signal of the first sub-detector 300a can be coupled to light generated by the first driving signal to detect the light. Accordingly, each sub-detector 300 can detect light of a driving signal for each wavelength.

[0113] The processor 142 can obtain information about the target object 10 by using the detection results classified according to the modulation signal, i.e., by using the detection results according to the wavelengths, in operation S1240. The information about the target object 10 can be physical property information. Herein, the target object 10 can be a human or an animal. Since the absorption rate of light differs according to the physical property of the target object 10, information about the target object 10 can be obtained by using the intensity of the detected light for each wavelength.

[0114] The optical apparatus described above can be provided in one housing. The optical apparatus can be a transmission type for detecting light transmitted through the target object 10 or can be a reflection type for detecting light reflected by the target object 10.

[0115] Examples of the optical apparatus using multi-wavelength light include a mobile phone, a smart phone, a laptop computer, a tablet computer, an e-book terminal, a digital broadcasting terminal, a PDA (Personal Digital Assistant), a portable multimedia player (PMP), an MP3 player, a digital camera, an Internet protocol television (IPTV), a digital television (DTV), a CE device (e.g., a refrigerator, an air conditioner, etc. having a display device), but are not limited thereto. The optical apparatus using multi-wavelength light described in the present specification can be a wearable device that can be worn by a user.

[0116] The optical device according to the embodiments does not require a hardware component for separating light of each wavelength because the optical device emits a plurality of lights having different narrow bandwidths and different center wavelengths. Accordingly, miniaturization of the optical device can be achieved. The optical device can detect light of one wavelength based on a waveform, thereby more accurately obtaining information about a target object through various waveform modulations.

[0117] It can be understood that the embodiments described herein can be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should be considered as available for other similar features or aspects in other embodiments.

[0118] While embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details can be made therein without departing from the spirit and scope as defined by the following claims.

Claims

1. An optical device using multi-wavelength light, the optical device comprising: substrate; A light-emitting array is disposed on the substrate and includes multiple light-emitting devices that emit multiple lights with different wavelengths; A controller is configured to control the light-emitting array such that the plurality of lights are modulated differently and emitted simultaneously; A photodetector is configured to detect light that is at least one of light scattered, transmitted, and reflected by a target object, wherein the light-emitting array emits the plurality of lights toward the target object; as well as The processor is configured to obtain information about the target object using the light detected by the photodetector. The photodetector includes multiple sub-detectors, each driven by a different second driving signal to detect light with a specific waveform. The controller is further configured to modulate the waveform of the first driving signal applied to the plurality of light-emitting devices differently, such that the plurality of light-emitting devices emit light with different waveforms from each other, and the plurality of sub-detectors are each driven by a second driving signal coupled to the first driving signal to detect the light emitted from the plurality of light-emitting devices according to the waveform. Each of the plurality of lights has a wavelength band of less than 15 nm, and the interval between the center wavelengths of the individual lights emitted by the light-emitting devices adjacent to each other in the light-emitting array is greater than the wavelength band of each of the plurality of lights, and is greater than or equal to 0.5 nm and less than or equal to 30 nm.

2. The optical device of claim 1, wherein the controller is configured to modulate any one or any combination of the frequency, amplitude, and phase of the first drive signal.

3. The optical device according to claim 1, wherein the waveform of the first driving signal includes any one or any combination of a sine wave, a square wave, a triangular wave, and a pulse wave.

4. The optical device according to claim 1, wherein the first waveform correlation of the first light emitted from at least two adjacent light-emitting devices in the plurality of light-emitting devices in the light-emitting array is greater than the second waveform correlation of the second light emitted from at least two non-adjacent light-emitting devices in the plurality of light-emitting devices.

5. The optical device of claim 1, wherein the first waveform correlation of the first light emitted from at least two adjacent light-emitting devices in the plurality of light-emitting devices in the light-emitting array is less than the second waveform correlation of the second light emitted from at least two non-adjacent light-emitting devices in the plurality of light-emitting devices.

6. The optical device according to claim 1, wherein the plurality of light-emitting devices are arranged two-dimensionally on the substrate.

7. The optical device according to claim 1, wherein the plurality of light-emitting devices are arranged sequentially in the light-emitting array along a first direction and emit the plurality of lights having wavelengths that change sequentially.

8. The optical device according to claim 1, wherein any one or any combination of the plurality of light-emitting devices is a laser or a light-emitting diode (LED).

9. The optical device according to claim 1, wherein any one or any combination of the plurality of light-emitting devices comprises: An active layer is disposed on the substrate and configured to generate light; as well as A wavelength-determining layer is configured to emit light of one of the plurality of wavelengths from the light generated by the active layer.

10. The optical device of claim 9, wherein one of the different wavelengths corresponds to any one or both of the thickness and dielectric constant of the wavelength-determining layer.

11. The optical device according to claim 9, wherein the active layer is disposed in the wavelength determination layer.

12. The optical device of claim 9, wherein the wavelength determination layer comprises a grating pattern structure.

13. The optical device of claim 12, wherein the wavelength determining layer comprises a plurality of dielectric layers spaced apart from each other in the longitudinal direction of the substrate.

14. The optical device according to claim 13, wherein the spacing between the plurality of dielectric layers varies continuously in the longitudinal direction of the substrate.

15. The optical device of claim 13, wherein the plurality of dielectric layers comprises: A first dielectric layer arranged with a first spacing; as well as A second dielectric layer arranged with a second spacing different from the first spacing.

16. The optical device according to claim 1, wherein the light-emitting array comprises: An active layer is disposed on the substrate and configured to generate light; as well as Multiple wavelength conversion layers are disposed on the active layer and configured to emit light generated by the active layer into the multiple wavelengths.

17. The optical device according to claim 16, further comprising: A barrier is disposed on the active layer and configured to separate the plurality of wavelength conversion layers.

18. The optical device of claim 1, wherein the photodetector comprises an image sensor.

19. The optical device of claim 1, wherein the processor is further configured to: For each wavelength of the plurality of light emitted by the light-emitting array, the light detected by the photodetector is classified; and Information about the target object is obtained by using light categorized for each wavelength.

20. A method of operating an optical device comprising a plurality of light-emitting devices, the method comprising: Multiple light sources with different wavelengths and modulations are emitted by multiple light-emitting devices included in a light-emitting array; The light is detected by a photodetector as follows: the light is at least one of light scattered, reflected, and transmitted by a target object, wherein the plurality of light-emitting devices emit the plurality of light toward the target object; Based on the modulation of the multiple light sources, the detected light is classified for each wavelength; as well as Information about the target object is obtained by using light categorized for each wavelength. The photodetector includes multiple sub-detectors, each driven by a different second driving signal to detect light with a specific waveform. The operation method further includes: modulating the waveforms of the first driving signal applied to the plurality of light-emitting devices differently, such that the plurality of light-emitting devices emit light with different waveforms from each other, and the plurality of sub-detectors are each driven by a second driving signal coupled to the first driving signal to detect the light emitted from the plurality of light-emitting devices according to the waveform. Each of the plurality of lights has a wavelength band of less than 15 nm, and the interval between the center wavelengths of the individual lights emitted by the light-emitting devices adjacent to each other in the light-emitting array is greater than the wavelength band of each of the plurality of lights, and is greater than or equal to 0.5 nm and less than or equal to 30 nm.

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