Light detection sensor and detection device including same

Abstract

The present invention relates to a light detection sensor and a detection device including same. According to the present invention, the light detection sensor of the present invention can adjust an energy barrier between a metal oxide and a metal electrode by means of a flexoelectric effect. The flexoelectric effect can be adjusted on a micrometer to millimeter scale. In addition, the detection device including the light detection sensor of the present invention may have high-performance static and dynamic sensor characteristics.

Description

Light detection sensor and detection device including the same

[0001] The present invention relates to a light detection sensor and a detection device including the same.

[0002] Electric polarization is generally sensitive to temperature changes. Research on the properties of this electric polarization has primarily focused on piezoelectric and ferroelectric materials. However, the flexoelectric effect can be used to induce electric polarization in materials other than piezoelectric and ferroelectric materials. The flexoelectric effect is the spontaneous electric polarization of centrosymmetric materials due to symmetry disruption in response to non-uniform mechanical shock. This effect can be used to detect heat, electricity, and light. However, the flexoelectric effect has only been observed at the nanoscale, requiring extensive research before its industrial application.

[0003] One object of the present invention is to provide a light detection sensor.

[0004] Another object of the present invention is to provide a target detection device including the above-described light detection sensor.

[0005] Another object of the present invention is to provide a speed detection device including the above-described optical detection sensor.

[0006] In order to achieve the above object, the present invention provides a light detection sensor including a dielectric layer, a metal electrode bonded to the dielectric layer, and an external force applying device that applies an external force to a location spaced apart from the metal electrode.

[0007] In addition, the present invention provides a target detection device that is mounted on a subject and detects a static or dynamic target, the target detection device including a dielectric layer, a metal electrode bonded to the dielectric layer, an external force applying device that applies an external force to a location spaced from the metal electrode, a light source that irradiates light in the direction of movement of the subject, and a current measuring device that measures pyroelectricity.

[0008] In addition, the present invention provides a speed detection device including a first light detection sensor having a first dielectric layer, a first metal electrode bonded to the first dielectric layer, and a first external force applying device for applying an external force to a position spaced apart from the first metal electrode, a second light detection sensor having a second dielectric layer, a second metal electrode bonded to the second dielectric layer, and a second external force applying device for applying an external force to a position spaced apart from the second metal electrode, and a second light detection sensor disposed spaced apart from the first light detection sensor, a light source for irradiating light to the first and second metal electrodes, and a current meter for measuring pyroelectricity.

[0009] According to the present invention, the photosensitive sensor of the present invention can control the energy barrier between the dielectric layer and the metal electrode by the flexoelectric effect. The flexoelectric effect can be controlled on the scale of micrometers to millimeters. Furthermore, a sensing device including the photosensitive sensor of the present invention can have high-performance static and dynamic sensor characteristics.

[0010] Figure 1 is a schematic diagram illustrating a light detection sensor according to an embodiment of the present invention.

[0011] Figure 2 is a current-voltage curve graph of an embodiment according to the present invention.

[0012] Figure 3 shows the forward current (I) of an embodiment according to the present invention. on ) and reverse current (I off ) ratio (I on / I off ) is a graph.

[0013] Figure 4 is a graph showing the Schottky barrier calculated at the silver / TiO2 junction of an embodiment according to the present invention.

[0014] Figure 5 is a schematic diagram for explaining a current map evaluation method of an embodiment according to the present invention.

[0015] Figure 6 is a current map image of an embodiment according to the present invention.

[0016] Figure 7 is a current distribution histogram of an embodiment according to the present invention.

[0017] Figure 8 is a graph of the electronic band structure at the silver / TiO2 junction of an embodiment according to the present invention.

[0018] Figure 9 is a graph of the electronic band structure according to an external force of an embodiment according to the present invention.

[0019] Figure 10 is a schematic diagram for explaining a method for evaluating light detection characteristics of an embodiment according to the present invention.

[0020] Figure 11 is a current-time graph of an embodiment according to the present invention.

[0021] Figure 12 shows the results of evaluating the optical response characteristics of an embodiment according to the present invention.

[0022] Figure 13 is a current-external force graph of an embodiment according to the present invention.

[0023] Figure 14 is a current-distance graph of an embodiment according to the present invention.

[0024] Figure 15 is a current-light intensity graph of an embodiment according to the present invention.

[0025] Figure 16 is a graph of light response according to the wavelength of light of an embodiment according to the present invention.

[0026] Figure 17 is a schematic diagram for explaining a speed monitoring device according to an embodiment of the present invention.

[0027] Figure 18 shows the evaluation results of a speed monitoring device according to an embodiment of the present invention.

[0028] Figure 19 shows the results of measuring the speed of various objects according to an embodiment of the present invention.

[0029] Figure 20 is a schematic diagram illustrating an obstacle detection method according to an embodiment of the present invention.

[0030] Figure 21 shows the reflection intensity of light and I according to the distance between the light source and the obstacle in an embodiment according to the present invention. py It's a graph.

[0031] Figure 22 shows the distance between the light source and the obstacle according to the embodiment of the present invention. py It is a rate of change graph.

[0032] Figure 23 is a schematic diagram illustrating a dynamic obstacle detection method according to an embodiment of the present invention.

[0033] Figure 24 is an I diagram of a dynamic obstacle according to an embodiment of the present invention. py This is a measurement graph.

[0034] Figure 25 is an example I of an embodiment according to the present invention. py This is the distribution of change rates.

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention can be modified in various ways and can take various forms, and thus specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used to indicate similar components. In the attached drawings, the dimensions of structures are shown larger than actual size to ensure clarity of the present invention.

[0036] While terms like "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0037] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0038] Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning within the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0039]

[0040] A light detection sensor according to an embodiment of the present invention may include a dielectric layer, a metal electrode bonded to the dielectric layer, and an external force applying device that applies an external force to a location spaced apart from the metal electrode.

[0041] In one embodiment, the dielectric layer may be formed of a material having central symmetry and may include, but is not limited to, one or more selected from the group consisting of titanium dioxide (TiO2), zinc oxide (ZnO), aluminum oxide (Al2O3), and silicon oxide (SiO2). In one embodiment, the dielectric layer may include titanium dioxide (TiO2).

[0042] In one embodiment, the metal electrode can be disposed on the first surface of the dielectric layer and can form a Schottky junction with the dielectric layer.

[0043] In one embodiment, the metal electrode may include, but is not limited to, one or more selected from the group consisting of silver (Ag), gold (Au), platinum (Pt), copper (Cu), iron (Fe), and nickel (Ni). In one embodiment, the metal electrode may include silver (Ag).

[0044] In one embodiment, the average thickness of the metal electrode may be greater than 0 and less than or equal to 200 nm. In one embodiment, the average thickness of the metal electrode may be about 40 to 120 nm.

[0045] In one embodiment, the external force applying device can apply the external force to a location on the first surface of the dielectric layer that is spaced apart from the metal electrode. In one embodiment, the external force applying device can apply the external force to a location on the first surface of the dielectric layer that is spaced apart from the metal electrode by 5 μm to 2 mm.

[0046] In one embodiment, the external force applying device may include one or more probe structures having a diameter of 10 to 1000 μm. In one embodiment, the external force applying device may include a probe structure having a diameter of about 120 μm.

[0047] In one embodiment, the probe structure can apply an external force of 0 to 30 μN or less to the first surface of the dielectric layer, but is not limited thereto.

[0048] In one embodiment, a flexoelectric element can be formed by causing a local deformation in the dielectric layer by the probe structure applying the external force, and the flexoelectric element can control the height of the Schottky barrier between the dielectric layer and the metal electrode.

[0049] In one embodiment, the light detection sensor can detect light with a wavelength of 300 to 1800 nm.

[0050] In one embodiment, the light detection sensor can detect light having an intensity of 0.5 mW / cm2 or greater.

[0051]

[0052] The object detection device according to an embodiment of the present invention is capable of detecting a static or dynamic object by being mounted on a subject, and may include a dielectric layer, a metal electrode bonded to the dielectric layer, an external force applying device that applies an external force to a location spaced apart from the metal electrode, a light source that irradiates light in the direction of movement of the subject, and a current measuring device that measures pyroelectricity.

[0053] In one embodiment, the dielectric layer may have central symmetry. In one embodiment, it may include TiO2 having central symmetry.

[0054] In one embodiment, the metal electrode can be disposed on the first surface of the dielectric layer and can form a Schottky junction with the dielectric layer.

[0055] In one embodiment, the external force applying device can cause local deformation in the dielectric layer by applying an external force to a location spaced apart from the metal electrode on the first surface of the dielectric layer.

[0056] In one embodiment, the current meter can measure pyroelectricity generated by a temperature change of the metal electrode caused by reflected light from the light source that is reflected from the object and incident on the metal electrode.

[0057] In one embodiment, the light source irradiates pulsed light of a first wavelength, and the first wavelength may be greater than a wavelength corresponding to a band gap energy of the dielectric layer.

[0058] In one embodiment, the current meter can measure the pyroelectricity as a function of the distance between the subject and the target. In one embodiment, as the distance between the subject and the target decreases, the intensity of the current generated by the pyroelectricity can rapidly increase.

[0059]

[0060] A speed detection device according to an embodiment of the present invention may include a first light detection sensor having a first dielectric layer, a first metal electrode bonded to the first dielectric layer, and a first external force applying device for applying an external force to a position spaced apart from the first metal electrode, a second light detection sensor having a second dielectric layer, a second metal electrode bonded to the second dielectric layer, and a second external force applying device for applying an external force to a position spaced apart from the second metal electrode, and disposed spaced apart from the first light detection sensor, a light source for irradiating light to the first and second metal electrodes, and a current meter for measuring pyroelectricity.

[0061] In one embodiment, the first dielectric layer and the second dielectric layer may have central symmetry. In one embodiment, the first dielectric layer and the second dielectric layer may include TiO2 having central symmetry.

[0062] In one embodiment, the first external force applying device and the second external force applying device can apply an external force to a location spaced apart from the metal electrode among the first surfaces of the first dielectric layer and the second dielectric layer to cause local deformation in the dielectric layer.

[0063] In one embodiment, the light source may be positioned opposite the first and second light detection sensors.

[0064] In one embodiment, the current meter can measure pyroelectricity generated by a temperature change of the metal electrode caused by reflected light from the light source that is reflected from the object and incident on the metal electrode.

[0065]

[0066] Hereinafter, to aid understanding of the present invention, examples will be given in detail. However, the following examples are intended only to illustrate the scope of the present invention and are not intended to limit its scope. These examples are provided to more fully explain the present invention to those of average skill in the art.

[0067]

[0068] <Example 1> Light detection sensor

[0069] Figure 1 is a schematic diagram illustrating a light detection sensor according to an embodiment of the present invention.

[0070] Single-crystal TiO2 (MTI Korea) was washed with acetone, methanol, and deionized water to prepare a single-crystal TiO2 substrate. Titanium and silver electrodes with an average diameter of approximately 1 mm and an average thickness of approximately 80 nm were deposited on one side of the single-crystal TiO2 substrate using electron beam (e-beam) vacuum deposition, spaced apart from each other. An external force was applied using a gold probe (Au probe, average diameter of approximately 120 μm). A current meter (Keithley 4200) was connected to the titanium and silver electrodes to evaluate their characteristics.

[0071]

[0072] <Example 2> Speed ​​and obstacle detection device

[0073] speed detection device

[0074] Figure 17 is a schematic diagram illustrating a speed detection device according to an embodiment of the present invention.

[0075] According to the above schematic diagram, the first and second photodetection sensors manufactured in Example 1 were placed spaced apart from each other. A current meter (Keithley 4200) connected to the first and second photodetection sensors was prepared. A light source (LED, λ = 365 to 1720 nm) was placed opposite the two photodetection sensors to irradiate light onto the electrodes, and the light source was controlled by a function generator (MFG-3013A, MCH Instruments). The current meter measured the pyroelectricity induced in the first and second photodetection sensors.

[0076]

[0077] Obstacle detection device

[0078] Figure 20 is a schematic diagram for explaining an obstacle detection method according to an embodiment of the present invention.

[0079] According to the above schematic diagram, the photodetector, current meter (Keithley 4200), and light source (LED, λ = 365 to 1720 nm) manufactured in Example 1 were attached to the subject. The light source was controlled by a function generator (MFG-3013A, MCH Instruments). The current meter measured the pyroelectricity generated by reflected light reflected from an obstacle.

[0080]

[0081] <Experimental Example 1> Electrical Characteristics Evaluation

[0082] The electrical characteristics of an embodiment of the present invention were evaluated with reference to the schematic diagram of Fig. 1.

[0083] In the above schematic diagram, an external force (gate force, F) is applied to a single crystal TiO2 at a constant distance (d = about 5 ㎛ to 2 mm) from a silver electrode using a gold probe (average diameter of about 120 ㎛). g) was applied. The electrical characteristics of the examples according to the external force were evaluated and are shown in Figs. 2 to 4. To evaluate the electrical characteristics, a semiconductor device parameter analyzer (Keithley 4200) and a voltage pulse generator (Model 4225-PMU and 4225-RPM) were used.

[0084] Figure 2 is a current-voltage curve graph of an embodiment according to the present invention. Figure 2 shows the schematic diagram of Figure 1, in which the distance between the gold probe and the silver electrode was fixed to about 1 mm (d = about 1, 1.4, and 2 mm) under dark conditions, and various external forces (F g = about 0, The current characteristics were measured when applying external forces (4, 8, 12, 16, and 20 μN). As the external force increased, the reverse current (I off ) increased, but the forward current (I on ) showed almost no change. This confirmed that external force has a great influence on the reverse current.

[0085] Figure 3 shows the forward current (I) of an embodiment according to the present invention. on ) and reverse current (I off ) ratio (I on / I off ) is a graph. Figure 3 shows the current-voltage curve graph when the distance between the gold probe and the silver electrode is about 1 mm. on / I off was evaluated. When there is no external force (F g = 0 N) to I on / I off had a value of about 4.9. This value was attributed to the Schottky junction of silver / TiO2. When the external force was increased to about 20 μN, I on / I off It was confirmed that it increases linearly and has a sensitivity of approximately 1.68 / μN. I on / I offThe linear change of the indicated current transfer at the silver / TiO2 junction could be mechanically controlled, suggesting its potential use as an asymmetric electrode.

[0086] Fig. 4 is a graph showing the Schottky barrier calculated at a silver / TiO2 junction according to an embodiment of the present invention. Fig. 4 shows the energy barrier calculated using a current-voltage curve graph when the distance between the gold probe and the silver electrode is approximately 1 mm. The Schottky barrier (Φ) at the silver / TiO2 junction was calculated according to the following equation 1.

[0087] [Formula 1]

[0088]

[0089] In the above equation 1, A * The Richardson constant for thermionic emission is about 1265.57 A / cm2K for TiO2. 2 is. A represents the electrode area, T represents the absolute temperature, e represents the atomic charge, and K represents the Boltzmann constant. In Fig. 4, the Schottky barrier changed linearly according to the external force, and the sensitivity of the Schottky barrier was confirmed to be approximately 3 meV / μN. Through this, it was confirmed that the Schottky barrier can be controlled according to the external force.

[0090] Figure 5 is a schematic diagram illustrating a current map evaluation method according to an embodiment of the present invention. To determine the current map, a conductive atomic force microscope (cAFM, Asylum research) was used. The measurement range of the cAFM is 3×3 ㎛. 2 The probe of the cAFM used a platinum and iridium-covered conductive silicon probe (AC240TM). The probe was fixed at a force (F tip = about 62.8 nN) and voltage (V tip = Approximately 6.0 V) by applying various external forces (F g= was measured at approximately 0, 5, 15, and 20 μN). At this time, the distance between the probe and the external force was approximately 2 mm. The current map in Fig. 6 confirmed that the flexoelectric effect modulates the Schottky barrier to change charge transfer. In addition, it was confirmed in Fig. 7 that the average current increased from 0.55 nA to 1.16 nA as the external force increased.

[0091] Through Figures 2 and 6, it was confirmed that the Schottky barrier can be changed and charge transfer can be effectively controlled by the flexoelectric effect generated by an external force.

[0092] Fig. 8 is a graph of the electronic band structure at a silver / TiO2 junction according to an embodiment of the present invention. Fig. 9 is a graph of the electronic band structure according to an external force of an embodiment of the present invention. The electronic band structures of Figs. 8 and 9 were determined using a simulation (COMSOL Multiphysics 6.0). In Fig. 8, it was confirmed that a Schottky barrier of approximately 0.59 eV was formed at the silver / TiO2 interface. In the inserted graph of Fig. 9, it was confirmed that the hole density increased as the external force increased. This means that the charge induced by the external force can change the band alignment and thereby control the Schottky barrier.

[0093]

[0094] <Experimental Example 2> Evaluation of light detection characteristics

[0095] The light-sensing characteristics of an embodiment of the present invention were evaluated with reference to the schematic diagram of Fig. 10. The light-sensing characteristics were evaluated by irradiating the silver electrode with light (wavelength, λ = approximately 940 nm, intensity, P = 0.8 to 2 mW / cm2), and confirmed in Figs. 11 to 16.

[0096] Figure 11 is a current-time graph of an embodiment according to the present invention. In Figure 11, the current was confirmed depending on whether an external force and light were irradiated. When there was no external force (F g= 0 μN), two current peaks (I py ) occurred. When the external force increases to about 16 μN, I py The increase was significant from about 0.4 nA to 62 nA. The silver electrode is an opaque material that does not transmit light, and when there is no external force (F g I of = 0 μN) py The change is due to the pyroelectric properties. When an external force is applied (F g = I of about 16 μN) py The change is because the polarization phenomenon occurred due to the flexoelectric effect caused by external force.

[0097] Figure 12 shows the results of evaluating the optical response characteristics of an embodiment according to the present invention. To evaluate the optical response characteristics, I for an ultrafast pulse (P = 0.8 ㎽ / ㎠) py was measured. I by the irradiated light py When the is formed and the light is removed, I py Exponential decay occurs. At this time, I py The time taken to reach approximately 63.2% of the maximum value (τ) r ) was measured to be approximately 14 ns. This allows detection of more than 10 million bits per second and a 3-dB bandwidth evaluation (I py The frequency at which the frequency decreases from its maximum value to 0.707, f 3dB =0.35 / τ r ) was confirmed to be 25 ㎒. In addition, I py Ga I py = It decreased proportionally beyond the maximum value.

[0098] Figure 13 is a current-external force graph of an embodiment according to the present invention. As the external force increases from 0 to about 20 μN, I py The intensity increased linearly from about 0.4 to 72 ㎁, and I py It was confirmed that the sensitivity was approximately 3.6 ㎁ / μN. I pyTo determine the increase rate, it was calculated according to Equation 2 below.

[0099] [Formula 2]

[0100]

[0101] In the above equation 2, I0 and I 20 are each F g I when 0 and 20 py The value is . The increase ratio calculated according to the above formula 2 is approximately 1.79 Х 10 4 It was confirmed by .

[0102] Fig. 14 is a current-distance graph of an embodiment according to the present invention. In the schematic diagram of Fig. 10, under the condition that the distance (d) between the silver electrode and the external force changes from 5 ㎛ to 2 mm, I py (P = 1 ㎽ / ㎠) was measured and the results are shown in Fig. 14. I py It gradually decreased as d increased. I py The decreasing curve is I py = 1 / d α It was fitted to the same power law, and the above α was confirmed to be approximately 0.17.

[0103] Figure 15 is a current-light intensity graph of an embodiment according to the present invention. The light intensity increases from 0.01 mW / cm2 to 2 mW / cm2, and I py The intensity increased linearly. I py It is related to the polarization that occurs at the silver / TiO2 interface due to the flexoelectric effect generated by the irradiation and removal of light. In Fig. 9, it was confirmed that the Schottky barrier height at the silver / TiO2 interface increases as the external force increases. As the Schottky barrier height increases, the size of the silver / TiO2 polarization at the interface is enhanced, so that I py The intensity increased. Through Fig. 9 and Fig. 15, the intensity of light, I py It was found that the strength and external force are related to the band alignment of the silver / TiO2 interface.

[0104] Figure 16 is a graph of the light response according to the wavelength of light of an embodiment according to the present invention. In addition to a specific wavelength, the light response (R = I) from ultraviolet (about 365 nm) to near infrared (about 1720 nm) py / PA) was evaluated. The light intensity was set to approximately 2 ㎽ / ㎠, the external force was set to approximately 20 μN, and the distance between the silver electrode and the external force was set to approximately 1 mm. The photoresponse was I py It shows the sensitivity to I in various wavelength ranges through Fig. 16. py It was confirmed that I was generated. Since the wavelength of light far exceeds the energy band gap (approximately 3.4 eV) of TiO2, I was generated by the temperature change due to light absorption. py was formed.

[0105]

[0106]

[0107] <Experimental Example 3> Speed ​​and Obstacle Detection Characteristics

[0108] Fig. 17 is a schematic diagram for explaining a speed detection device according to an embodiment of the present invention. In Fig. 17, the speed detection device is arranged with a first light detection sensor (channel-1) and a second light detection sensor (channel-2) at a constant interval (s = about 1 cm), and a continuous light source (λ = about 940 nm, P = 22 mW / cm2) is arranged to face the first light detection sensor and the second light detection sensor. In order to determine the performance of the speed detection device, a toy car moving at a specific speed (v) was used. The toy car moved between the light sensor and the light source, thereby blocking the light irradiated to the light sensor by the toy car. At this time, the intensity of the light changed rapidly, and the first light detection sensor and the second light detection sensor each had an intensity of I py was created. According to Newton's laws of motion, the I of the first light detection sensor py I of the peak and second light detection sensors pyThe time difference (Δt) of the peak of the above light detection sensor has a corresponding relationship with the speed of the toy car, and can be expressed as v=s / Δt.

[0109] Fig. 18 shows the evaluation results of a speed detection device according to an embodiment of the present invention. Fig. 18 shows the results of measuring Δt according to the schematic diagram of Fig. 17. Δt was confirmed to be approximately 886 μs, and the speed was calculated to be approximately 40.3 km / h. The actual speed of the toy car was approximately 40.2 km / h, and the speed of the toy car measured by the monitoring device and the actual speed of the toy car were in good agreement.

[0110] Figure 19 shows the results of various subject speed measurements according to an embodiment of the present invention. The speed measurements for various conditions and subjects achieved an accuracy of 99.7%, confirming the accuracy of the monitoring device. The monitoring device was found to be capable of operating at an ultra-high speed of approximately 14 ns, distinguishing between two current peaks within approximately 50 μs, and detecting speeds of approximately 720 km / h or less.

[0111] Fig. 20 is a schematic diagram for explaining an obstacle detection method according to an embodiment of the present invention. When a toy car is driven toward a stationary obstacle with a continuous light source (λ = about 940 nm, P = 22 mW / cm2) and a light detection sensor attached to it, I py The response change of the toy car was observed. The light source of the toy car is reflected by an obstacle, and the intensity of the reflected light and the I generated according to the reflected light were py changed according to the distance (s) between the light source and the obstacle. In Fig. 21, the light reflection intensity and I according to the distance between the light source and the obstacle py The relationship was confirmed.

[0112] Figure 21 shows the reflection intensity of light and I according to the distance between the light source and the obstacle in an embodiment according to the present invention. py It's a graph. Ipy It depends on the intensity of light reflection and gradually decreases as the distance between the light source and the obstacle increases.

[0113] Figure 22 shows the distance between the light source and the obstacle according to the embodiment of the present invention. py This is a graph of the rate of change. In Fig. 22, I py Rate of change (ΔI py / Δs) depended only on the distance between the light source and the obstacle. As the distance between the light source and the obstacle decreased, I py The rate of change increased rapidly, allowing us to determine the degree of approach of obstacles.

[0114] Figure 23 is a schematic diagram illustrating a dynamic obstacle detection method according to an embodiment of the present invention.

[0115] Figure 24 is an I diagram of a dynamic obstacle according to an embodiment of the present invention. py This is a measurement graph. When no obstacle appears in front of the toy car, there is no reflected light, so I py No change was observed. However, when an obstacle appeared, depending on the distance between the toy car and the obstacle, I py has increased or decreased.

[0116] Figure 25 is an example I of an embodiment according to the present invention. py This is the change rate distribution diagram. I in Fig. 24 py The rapid change in is related to the distance between the toy car and the obstacle, I py The change rate is represented as a distribution diagram. In Figure 24, a positive change rate indicates a potential collision, and a negative change rate indicates a safe distance.

[0117]

[0118] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A dielectric layer formed of a material having central symmetry; A metal electrode disposed on the first surface of the dielectric layer and forming a Schottky junction with the dielectric layer; and A light-sensitive sensor, comprising: an external force applying device that applies an external force to a location spaced from the metal electrode on the first surface of the dielectric layer to cause local deformation in the dielectric layer.

2. In paragraph 1, The above dielectric layer is made of titanium dioxide (TiO 2 ), zinc oxide (ZnO), aluminum oxide (Al 2 O 3 ) and silicon oxide (SiO 2 ) comprising at least one selected from the group consisting of, A light-sensitive sensor, wherein the metal electrode comprises at least one selected from the group consisting of silver (Ag), gold (Au), platinum (Pt), copper (Cu), iron (Fe), and nickel (Ni).

3. In paragraph 1, A light-sensitive sensor, wherein the external force applying device applies an external force to a position spaced apart from the metal electrode by 5 ㎛ to 2 mm on the first surface of the dielectric layer, and includes one or more probe structures having a diameter of 10 to 1000 ㎛.

4. In paragraph 3, The above probe structure is a light-sensitive sensor that applies an external force of 0 to 30 μN to the first surface of the dielectric layer.

5. In paragraph 4, A light-sensitive sensor, wherein the height of a Schottky barrier between the dielectric layer and the metal electrode is controlled by a flexoelectric potential of the dielectric layer caused by a probe structure applying the external force.

6. In paragraph 1, A light detection sensor having a rise time of 10 to 20 ns.

7. In paragraph 1, The above light detection sensor is a light detection sensor that detects light with a wavelength of 300 to 1800 nm.

8. In paragraph 1, The above light detection sensor is a light detection sensor that detects light having an intensity of 0.5 mW / cm2 or greater.

9. In paragraph 1, A light-sensitive sensor, wherein the average thickness of the metal electrode is greater than 0 and less than or equal to 200 nm.

10. In a detection device mounted on a subject and detecting a static or dynamic object, A dielectric layer formed of a material having central symmetry; A metal electrode disposed on the first surface of the dielectric layer and forming a Schottky bond with the dielectric layer; An external force applying device that applies an external force to a location spaced from the metal electrode on the first surface of the dielectric layer to cause local deformation of the dielectric layer; A light source that irradiates light in the direction of movement of the subject; and An object detection device, comprising: a current measuring device that measures pyroelectricity generated by a temperature change of the metal electrode caused by reflected light from the object among light irradiated from the light source and incident on the metal electrode.

11. In paragraph 10, The above light source irradiates pulse light of the first wavelength, A target detection device, wherein the first wavelength is larger than a wavelength corresponding to the band gap energy of the dielectric layer.

12. In paragraph 10, The above current meter is an object detection device that measures the pyroelectricity as a function of the distance between the subject and the object.

13. A first light detection sensor comprising: a first dielectric layer formed of a material having central symmetry; a first metal electrode disposed on a first surface of the first dielectric layer and forming a Schottky junction at an interface with the first dielectric layer; and a first external force applying device that applies an external force to a location on the first surface of the first dielectric layer spaced apart from the first metal electrode to cause local deformation in the first dielectric layer; A second dielectric layer formed of a material having central symmetry; a second metal electrode disposed on a first surface of the second dielectric layer and forming a Schottky junction at an interface with the second dielectric layer; and a second external force applying device applying an external force to a location on the first surface of the second dielectric layer spaced apart from the second metal electrode to cause local deformation in the second dielectric layer; and a second light detection sensor disposed spaced apart from the first light sensor; A light source positioned opposite to the first and second light sensors and irradiating light to the first and second metal electrodes; and A speed detection device, comprising: a current meter for measuring the first pyroelectricity generated in the first light sensor and the pyroelectricity caused in the second light sensor.

14. In paragraph 13, The above speed detection device is a speed detection device that detects a speed exceeding 0 and less than 750 km / h.

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