WO2008100097A1

WO2008100097A1 - An optical module for observing an event or an object

Info

Publication number: WO2008100097A1
Application number: PCT/KR2008/000882
Authority: WO
Inventors: Il Hung Park; Jae Hyoung Park
Original assignee: Ewha Womans University
Current assignee: Ewha Womans University
Priority date: 2007-02-14
Filing date: 2008-02-14
Publication date: 2008-08-21
Anticipated expiration: 2009-08-14
Also published as: KR100715236B1

Abstract

An optical module is disclosed which can effectively observe an event or object. The optical module includes: a first mirror with a wide field of view (FOV), for detecting the event or object over a wide area of observation; a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror; an optical signal detector for detecting an optical signal transmitted from the first mirror or the second mirror; a body including the first mirror, the second mirror, and the optical signal detector therein, and forming apertures which correspond to the first mirror and the second mirror, respectively, the body providing an optical path from the first mirror or the second mirror to the optical signal detector; and a controller for determining whether the detected event or object is a target of observation, for reading a position of the detected event or object when concluding that the detected event or object is a target of observation, and for controlling the first mirror and the second mirrors. The controller provides an optical path to only one of the mirror cells of the second mirror, which corresponds to the particular position of the event or object detected by the first mirror, and to block optical paths to the remaining mirror cells. The optical module is configured to include: a first mirror having a wide FOV, for detecting the event or object over a wide area of observation; and a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide are of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror.

Description

AN OPTICAL MODULE FOR OBSERVING AN EVENT OR AN

OBJECT

Technical Field

[1] The present invention relates to an optical system. More particularly, this invention relates to an optical module that effectively observes a rapidly moving event or object, which is configured to include: a first mirror having a wide field of view (FOV), for detecting the event or object over a wide area of observation; and a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells controlling the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror. Background Art

[2] Recently, global electrical phenomena in the earth's atmosphere have been understood through the observation of transient luminous events (TLE). Research linked these phenomena to the earth's weather and to the activities of the sun and the earth. This is because these phenomena, such as TLE, include a variety of information related to the earth and space.

[3] However, it is not effective to perform a global observation of an event or object, such as TLE, on the surface of the earth. This is because there are few places that are higher than the location where the global electrical phenomena have occurred. Also, although few suitable places do exist, they do not allow for a global observation of the phenomena to be carried out simultaneously.

[4] In addition, when space is observed near the earth's polar orbit as a detector detects a radio frequency based on above the earth or space and images acquired through detection are developed, such an observation has advantages in that information about the earth atmosphere's electrical activities can be widely provided from all topographical areas of the earth during the total operation time of a satellite. To observe a rapidly moving event/object on the earth's surface from a satellite requires proper optical systems. However, optical systems cannot always observe a rapidly moving event/object on the earth's surface.

[5] Recently though, a micro-electro-mechanical system (MEMS) has come under the spotlight, where small mechanical devices, such as a sensor valve, gear, mirror, and semiconductor chip manipulator, etc., are combined with a computer. MEMS is also called 'smart matter.' MEMS is an apparatus comprised of a silicon chip with a micro circuit. The MEMS is inserted into a mechanical apparatus, such as a mirror or sensor, when the mechanical apparatus is manufactured. The MEMS is employed in various systems, such as: an apparatus for inflating a vehicle's air bag to match with a user's weight and with the speed detected by the air bag sensor; a global position system (GPS) sensor that can indicate a continuous track of freight transportation and handling freight processes; a sensor that detects air flow change according to air resistance on the surface of airplane wings and performs interaction; an optical switching apparatus that outputs optical signals at 20 m/ns, a cooling/heating apparatus for operating a sensor; and a sensor installed in a building, for changing the flexibility of matter that reacts to atmospheric pressure. Considering the features and advantages of MEMS technology, it is necessary that the technology be applied to an optical module for observing an event or an object. Disclosure of Invention Technical Problem

[6] Therefore, the present invention has been made in view of the above problems, and provides an optical module that can effectively observe a rapidly moving event or object, in which the optical module includes: a first mirror having a wide field of view (FOV), for detecting the event or object over a wide area of observation; and a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror. Technical Solution

[7] In accordance with an exemplary embodiment of the present invention, the present invention provides an optical module for observing an event or object including: a first mirror with a wide field of view (FOV), for detecting the event or object over a wide area of observation; a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror; an optical signal detector for detecting an optical signal transmitted from the first mirror or the second mirror; a body including the first mirror, the second mirror, and the optical signal detector therein, and forming apertures which correspond to the first mirror and the second mirror, respectively, the body providing an optical path from the first mirror or the second mirror to the optical signal detector; and a controller for determining whether the detected event or object is a target of observation, for reading a position of the detected event or object when concluding that the detected event or object is a target of observation, and for controlling the first mirror and the second mirrors. Here, the controller provides an optical path to only one of the mirror cells of the second mirror, which corresponds to the particular position of the event or object detected by the first mirror, and to block optical paths to the remaining mirror cells.

[8] Preferably, the first mirror includes a digital mirror that is switched off after detecting the event or object.

[9] Preferably, the respective mirror cells of the second mirror comprise a digital mirror that is switched on/off according to a control signal of the controller.

[10] Preferably, the first mirror and the second mirror change the optical path of an image to a certain path.

[11] Preferably, the second mirror can be controlled to provide a certain resolution.

[12] Preferably, the first mirror and the second mirrors are operated through a micro electro mechanical system (MEMS).

Advantageous Effects

[13] As described above, the optical module according to the present invention can effectively observe an event or object, which is configured to include: a first mirror having a wide field of view (FOV), for detecting the event or object over a wide area of observation; and a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror. Brief Description of the Drawings

[14] The features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which:

[15] Figure 1 is a view illustrating an optical module according to an embodiment of the present invention;

[16] Figure 2 are views describing the operation principle of an optical module according to an embodiment of the present invention, in which: Figure 2A is a view describing a process for detecting an event or an object in a wide area of observation, particularly a rapidly moving event or object, for example, transient luminous events (TLE), using a first mirror 110 having a wide field of view; and Figure 2B is a view describing a process for observing, in detail, at a high resolution, a particular position of the event or object detected by the process of Figure 2A, using one of the mirror cells with a relatively long focal length and a high resolving power, included in a second mirror 120, in which the one of the mirrors corresponds to the particular position of an event or object.

[17] <Brief Description of Symbols in the Drawings>

[18] 110: first mirror

[19] 120: second mirror (2x2 mirror cells)

[20] 130: light signal detector

[21] 132: ultraviolet region detector

[22] 133: analog board

[23] 134: digital board

[24] 135: PMT power supply

[25] 137: near infrared region detector

[26] 138: near infrared region electronic device

[27] 140: body

[28] 142, 144: aperture

[29] 150: data storage unit

[30] 160: interface unit

[31] 170: controller

[32] 180: power supply

[33] 190: entire area of observation

[34] 192: area observed by a first mirror

[35] 194: area observed by the entire mirror cells included in second mirror

[36] 196: particular position of the entire area of observation

[37] 198: area observed by a mirror cell of the mirror cells included in a second mirror, which corresponds to a particular position of the entire area of observation

[38] 240: field of view (FOV)

[39] 250: rapidly moving event or object

Best Mode for Carrying Out the Invention

[40] Preferred embodiments according to an optical module of the present invention will be described in detail with reference to the accompanying drawings.

[41] Figure 1 is a view illustrating an optical module 100 according to an embodiment of the present invention. As shown in Figure 1, the optical module 100 is configured in such a way that: a first mirror 110 detects an event or object over a wide area, based on its wide FOV; a second mirror 120 includes a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror; an optical signal detector 130 detects optical signals in light transmitted from the first mirror 110 or at least one or more second mirrors 120; and a body 140 includes the first mirror 110, at least one or more second mirrors 120, and the optical signal detector 130 therein. Here, the body 140 forms apertures 142 and 144 which correspond to the first mirror 110 and at least one or more second mirrors 120, respectively. As well, the optical module 100 further includes a data storage unit 150 for storing the detected optical signal, an interface unit 160 for connecting between elements in the optical module 100, a controller 170 for controlling the entire operation of the system, and a power supply 180 for supplying power to the elements in the optical module 100.

[42] The first mirror 110 serves to detect an event or object, particularly a rapidly moving event or object (for example, TLE), over a wide area using its wide FOV. As shown in Figure 1, the first mirror 110 is located close to the optical signal detector 130 in the body 140. The first mirror 110 has a relatively short focal length and the body 140 has an aperture 142 corresponding to the focal length. Specifically, the first mirror 110 is preferably implemented by a MEMS micro-mirror array that can be turned on/off in a digital method, allowing the second mirror 120 to observe the event or object detected by the first mirror 110 at a high resolution. Also, as shown in Figure 1, the first mirror 110 is aligned so that it can change the optical path of an event image or an object image to a certain path to transmit it to the optical signal detector 130.

[43] The second mirror 120 serves to observe in detail the event or the object (for example, TLE) detected by the first mirror 110 using its high resolving power. The second mirror 120 is configured to include a plurality of mirror cells that control the wide area of observation 190 detected by the first mirror 110, correspondingly and respectively. In the present embodiment, the mirror cells are implemented in a 2 x 2 matrix block as shown in Figure 1. In comparison with the first mirror 110, each of the plurality of mirror cells is located relatively far from the optical signal detector 130 in the body 140. Also, each mirror cell has a relatively long focal length. Furthermore, each mirror cell is associated with a corresponding aperture 144. The second mirror is configured in such a way that one of the mirror cells, which corresponds to a particular position 196 of the wide area of observation 190 that the first mirror 110 controls, can observe, at a high resolution, the event or object in the wide area of observation 190 detected by the first mirror 110. To this end, the optical module 100 according to the present invention includes a controller 170 and may further include another controlling unit (not shown). The controller 170: determines whether the event or object detected by the first mirror 110 is a target of observation; reads the position of the event or object when concluding that the event or object is a target of observation; controls the first mirror 110 and the second mirror 120 in such a way to provide an optical path to only one of the mirror cells of the second mirror 120, which corresponds to a particular position 196 of the event or object detected by the first mirror 110, and to block optical paths to the remaining mirror cells.

[44] It is preferable that the respective mirror cells of the second mirror 120 are implemented by an MEMS micro-mirror array employing a digital method so that they can be turned on/off according to a control signal of the controller. As shown in Figure 1, similar to the first mirror 110, the second mirror 120 is aligned so that it can change the optical path of an event image or an object image to a certain path to transmit it to the optical signal detector 130. Although, as shown in Figure 1, in the embodiment of the present invention, the second mirror 120 is implemented by only one mirror, it will be easily appreciated that the second mirror 120 can be configured to include a plurality of mirrors.

[45] Referring to Figure 1, the connection between an area of observation controlled by the first mirror 110 and an area of observation controlled by the second mirror 120 and each of the plurality of mirror cells of the second mirror 120 is described as follows. As shown in Figure 1, the area of observation 192 controlled by the first mirror 110 (referred to as a first observation area 192) is the same as the entire area of observation 190 and the area of observation 194 controlled by the second mirror 120 (referred to as a second observation area 194) is also the same as the entire area of observation 190. That is, the first observation area 192 of the first mirror 110 can be controlled by the second mirror 120. In addition, the mirror cells of the second mirror 120 can control the first observation area 192, partially and respectively. For example, as shown in Figure 1, one particular mirror cell controls a target of observation 198 that corresponds to a partial area 196 of the entire area of observation 190. That is, the first observation area 192 controlled by the first mirror 110, i.e., the entire area of observation 190, can be controlled by the second mirror 120. In other words, the respective mirror cells of the second mirror 120 can control particular partial areas of the first observation area 192, i.e., the entire area of observation 190.

[46] The optical signal detector 130 serves to detect optical signals from the first mirror

110 or the second mirror 120. Such an optical signal detector 130 includes an ultraviolet region detecting unit for detecting an optical signal in the ultra-violet region and a near infra-red region detecting unit for detection an optical signal in the near infrared region. The ultra-violet region detecting unit may be implemented by a multi- anode photomultiplier tube (MAPMT). In an embodiment of the present invention as shown in Figure 1, the ultra-violet detecting unit includes: an ultra-violet region detector 132, configured by an MAPMT, for detecting an optical signal in the ultraviolet region; an analog board 132 and digital board 134 for operating the ultra-violet region detector 132; and a PMT power supply for supplying power to the MAPMT. Also, the near infra-red region detecting unit includes: a near infra-red region detector 137 for detecting an optical signal in the near infra-red region; and a near infra-red region electric device 138 for operating the infra-red region detector 137. In the embodiment of the present invention as shown in Figure 1, although the optical system is implemented to detect only the ultra-violet region signal and near infra-red region signal, it will be easily appreciated to a person skilled in the art that the spectral range of detectable optical signals would not be limited by the embodiment. As well, the electrical device (that corresponds to an electric signal processing unit) for the optical signal detector 130 is not limited by the embodiment of Figure 1.

[47] The body 140 includes the first mirror 110, the second mirror 120, and the optical signal detector 130 therein. The body 140 provides an optical path from the first mirror 110 or the second mirror 120 to the optical signal detector 130. As well, the body 140 forms the apertures 142 and 144 at the lower portion of the first and second mirrors 110 and 120, respectively. Here, aperture collimators (not shown) may be further installed to the apertures 142 and 144, respectively.

[48] The data storage unit 150 stores the detected optical signals and is implemented by a hard disk, etc. The interface unit 160 serves as a connection between the devices in the system and is implemented by a bus interface, etc. The controller 170 refers to a CPU to control the entire operation of the system. Specifically, as described above, the controller 170 is operated in such a way that: a determination is made as to whether the event or object detected by the first mirror 110 is a target of observation, using the electric signal processing units included in the optical signal detector 130; the location of the detected event or object is read when the detected event or object is a target of observation; and the first and second mirrors are controlled based on the read location. Here, such a controller may be installed into the optical signal detector. The power supply 180 supplies power to devices in the system.

[49] The following is a description of the operation principle of an optical module according to the present invention, referring to Figures 2A and 2B.

[50] Figure 2 are views describing the operation principle of an optical module according to an embodiment of the present invention, in which: Figure 2A is a view describing a process for detecting an event or object in a wide area of observation, particularly a rapidly moving event or object, for example, transient luminous events (TLE), using a first mirror 110 having a wide FOV; and Figure 2B is a view describing a process for observing, in detail, at a high resolution, a particular position of the event or object detected by the process of Figure 2A, using one of the mirror cells with a relatively long focal length and a high resolution, included in a second mirror 120, in which one of the mirrors corresponds to the particular position of an event or object.

[51] As shown in Figure 2A, the optical module of the present invention initially tries to detect an event or object 250, for example, transient luminous events (TLE), over a wide area of observation, using the first mirror 110 for a wide FOV, which is referred to as an event/object detecting process. Here, since the first mirror 110 has features where its resolution is not high but its view angle is large, it is used to detect an event or object over a wide area of observation. The field of view (FOV) 240 of the first mirror 110 is shown in Figure 2A. The event or object 250 detected by the first mirror 110 is transmitted to the optical signal detector 130 to determine whether the detected event or object is a target of observation. When it is determined that the detected event or object 250 is a target of observation, the process proceeds to an event/object observing process as shown in Figure 2B.

[52] In the event/object observing process, a particular position of the event or object, detected through the event/object detecting process of Figure 2A, is observed in detail by one of the mirror cells of the second mirror cells 120, which corresponds to the particular position of the event or object, as only one of the mirror cells is turned on. Here, the mirror cells have a relatively long focal length and a high resolution. It is preferable that the respective mirror cells of the second mirror 120 are implemented by an MEMS micro-mirror array, operated in a digital method, so that they can be rapidly turned on/off according to a control signal of the controller. In this event/object observing process, the first mirror 110 must be switched off, and the second mirror 120 must be operated in such a way that only the mirror cell, which corresponds to a particular position of the detected event or object 250, is turned on and focused on the detected event or object 250, and the remaining mirror cells are turned off.

[53] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] An optical module for observing an event or object comprising: a first mirror with a wide field of view (FOV), for detecting the event or object over a wide area of observation; a second mirror including a plurality of mirror cells each of whose focal length is greater than that of the first mirror, in which the plurality of mirror cells control the wide area of observation detected by the first mirror, correspondingly and respectively, so that one of the mirror cells corresponding to a particular position of the wide area of observation can observe, at a high resolution, the event or object in the wide area of observation detected by the first mirror; an optical signal detector for detecting an optical signal transmitted from the first mirror or the second mirror; a body including the first mirror, the second mirror, and the optical signal detector therein, and forming apertures which correspond to the first mirror and the second mirror, respectively, the body providing an optical path from the first mirror or the second mirror to the optical signal detector; and a controller for determining whether the detected event or object is a target of observation, for reading a position of the detected event or object when concluding that the detected event or object is a target of observation, and for controlling the first mirror and the second mirrors, wherein the controller provides an optical path to only one of the mirror cells of the second mirror, which corresponds to the particular position of the event or object detected by the first mirror, and to block optical paths to the remaining mirror cells.

[2] The optical module according to claim 1, wherein the first mirror comprises a digital mirror that is switched off after detecting the event or object.

[3] The optical module according to claim 1, wherein the respective mirror cells of the second mirror comprise a digital mirror that is switched on/off according to a control signal of the controller.

[4] The optical module according to claim 1, wherein the first mirror and the second mirror change the optical path of an image to a certain path.

[5] The optical module according to claim 1, wherein the second mirror can be controlled to provide a certain resolution.

[6] The optical module according to any one of claims 1 to 5, wherein the first mirror and the second mirrors are operated through a micro electro mechanical system (MEMS).