JP2011076895A - Light irradiation device and imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light irradiation device capable of irradiating light of nearly uniform intensity on a given area with increase of power consumption restrained, and an imaging system using the irradiating device. <P>SOLUTION: The device is provided with an actuator equipped with an elastic member, a movable member attached to the elastic member and oscillating while being restrained by the elastic member, and a driving means for driving the movable member, a light-emitting means attached to the movable member for emitting light of a given frequency, an oscillation information acquiring means for acquiring information concerning oscillation of the movable member, and a control means carrying out control of increasing intensity of light emitted by the light-emitting means, the larger a motion speed of the movable member is, settled on the basis of the oscillation information acquired by the oscillation information acquiring means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light irradiation apparatus that irradiates light of a predetermined frequency and an imaging system using the light irradiation apparatus.

  2. Description of the Related Art Conventionally, an object detection system using a laser radar or a millimeter wave radar is known as a technique for detecting the presence / absence of an object existing outside a moving body such as an automobile and the distance to the object. The object detection system includes an actuator that scans a predetermined range with laser light or radio waves. As such an actuator, there is a movable member to which a component such as a lens or an antenna can be attached at the distal end of a leaf spring whose base end is fixed, and this movable member is vibrated by a driving means so that a predetermined region is laser-exposed. A leaf spring type actuator that scans with light or radio waves is known (see, for example, Patent Document 1). In this technique, when the system consisting of the movable member and the leaf spring is resonating, the magnitude of the moving member's operating speed is minimized at both ends of the vibration where the displacement is maximum, while the vibration of which the displacement is minimum. Maximum at the center.

JP 2003-177348 A

  By the way, in the above-described prior art, it is also conceivable to irradiate a predetermined region with light by directly attaching light emitting means such as a light emitting diode (LED) to the movable member. The intensity of light per unit area on the surface with the same distance from the light source (hereinafter referred to as irradiation intensity) is proportional to the time of light irradiation, so the irradiation intensity near both ends of the vibration of the movable member is the center of vibration. It becomes larger than the irradiation intensity in the vicinity. For this reason, when the light emitting means is directly attached to the movable member of the above-described conventional actuator, there is a problem in that the irradiation intensity in the irradiation region varies from place to place and the irradiation performance is degraded.

  In order to solve this problem, it is conceivable to irradiate the irradiation region uniformly by using a plurality of light sources. In this case, however, the light source portion becomes large and the power consumption increases remarkably. There was a problem that.

  The present invention has been made in view of the above, and a light irradiation apparatus capable of irradiating light with a substantially uniform intensity to a predetermined region while suppressing an increase in power consumption, and the light irradiation apparatus An object of the present invention is to provide an imaging system using the above.

  In order to solve the above-described problems and achieve the object, a light irradiation apparatus according to the present invention includes an elastic member, a movable member attached to the elastic member and vibrating while being restrained by the elastic member, and the movable member. An actuator having a driving means for driving the member; a light emitting means that is attached to the movable member and emits light of a predetermined frequency; a vibration information obtaining means for obtaining information related to vibration of the movable member; and the vibration Control means for performing control to increase the intensity of the light emitted by the light emitting means as the magnitude of the operation speed of the movable member determined based on the vibration information obtained by the information obtaining means is increased. And

  The light irradiation apparatus according to the present invention is characterized in that, in the above invention, the intensity of the light has a linear relationship with the magnitude of the operation speed of the movable member.

  In the light irradiation apparatus according to the present invention as set forth in the invention described above, the control unit corrects the intensity of the light according to a distance in the optical axis direction of the light emitting unit from the light emitting unit to a predetermined irradiation surface. It is characterized by that.

  In the light irradiation device according to the present invention, in the above invention, the driving means includes a magnet and a coil positioned in the vicinity of the magnet, and one of the magnet and the coil is the movable member. It is attached to.

  In the light irradiation apparatus according to the present invention as set forth in the invention described above, the vibration information is information on an induced electromotive force accompanying a change in magnetic flux across the coil.

  In the light irradiation apparatus according to the present invention as set forth in the invention described above, the vibration information is information related to a position of the elastic member.

  In the light irradiation apparatus according to the present invention as set forth in the invention described above, the light is visible light or infrared light.

  The light irradiation apparatus according to the present invention is characterized in that, in the above invention, the elastic member is a leaf spring.

  In the light irradiation apparatus according to the present invention, the elastic member is a torsion bar.

  An imaging system according to the present invention includes the light irradiation device according to the above-described invention and an imaging device that has an angle of view included in the light irradiation region by the light emitting unit and images a subject to generate image data. And a display device for displaying an image corresponding to the image data generated by the imaging device.

  According to the present invention, the intensity of light emitted from the light emitting means attached to the movable member of the actuator is controlled to increase as the operating speed of the movable member increases, so that while suppressing an increase in power consumption, It becomes possible to irradiate light almost uniformly to a predetermined region.

FIG. 1 is a perspective view showing a configuration of a main part of the light irradiation apparatus according to Embodiment 1 of the present invention. 2 is a plan view in the direction of arrow A in FIG. FIG. 3 is a diagram schematically showing the configuration of the light irradiation apparatus according to Embodiment 1 of the present invention. FIG. 4 is a diagram illustrating a state in which the movable member of the light irradiation apparatus according to Embodiment 1 of the present invention is located at the end point of vibration. FIG. 5 is a diagram showing a state in which the movable member of the light irradiation apparatus according to Embodiment 1 of the present invention is located at an end point of vibration different from that in FIG. 4. FIG. 6 is a diagram illustrating a temporal change in the position of the movable member and the intensity of light emitted from the light emitting element. FIG. 7 is a diagram showing a configuration of a light irradiation apparatus according to Embodiment 2 of the present invention. FIG. 8 is a diagram illustrating a setting example of the irradiation region of the light emitting element included in the light irradiation apparatus according to Embodiment 2 of the present invention. FIG. 9 is a diagram showing a configuration of an imaging system according to Embodiment 2 of the present invention. FIG. 10 is a diagram showing a configuration of a light irradiation apparatus according to Embodiment 3 of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings. Note that the drawings referred to in the following description are schematic, and when the same object is shown in different drawings, dimensions, scales, and the like may be different.

(Embodiment 1)
FIG. 1 is a perspective view showing a configuration of a main part of the light irradiation apparatus according to Embodiment 1 of the present invention. 2 is a plan view in the direction of arrow A in FIG. FIG. 3 is a diagram schematically showing the configuration of the light irradiation apparatus according to the first embodiment.

  The light irradiation device 1 shown in FIGS. 1 to 3 includes a light emitting element 2 as a light emitting means that emits light of a predetermined frequency, and a member (movable member described later) to which the light emitting element 2 is attached and vibrates together with the light emitting element 2. The actuator 3, the sensor unit 4 as vibration information acquisition means for acquiring information related to the vibration of the movable member of the actuator 3, and the operation of the light emitting element 2 and the actuator 3 are controlled based on the detection result of the sensor unit 4. And a control unit 5.

  The light emitting element 2 is realized by using, for example, a light emitting diode that emits visible light or infrared light having a predetermined frequency.

  The actuator 3 fixes two leaf springs 6 and 7 having the same shape, a fixing member 8 that fixes each base end portion of the leaf springs 6 and 7, and each distal end portion of the leaf springs 6 and 7, The movable member 9 that vibrates while being restrained by the leaf springs 6 and 7 and has the light emitting element 2 attached to the surface thereof, the thin plate-like magnet 10 whose main surface forms a semi-annular shape, and the magnet 10 are fixed to each other. 10, which forms a magnetic circuit together with 10, is held by the movable member 9, holds the magnet 10 and the coil 12 positioned in the vicinity of the yoke 11, and the fixed member 8, while the yoke 11 is fixed via the screw member 13. And a base member 14 provided.

  The sensor unit 4 is a light reflecting photo reflector including a light emitting element 41 and a light receiving element 42. In the sensor unit 4, the light emitting element 41 and the light receiving element 42 are opposed to one main surface of the leaf spring 6, and this main surface is a reflection surface of light emitted by the light emitting element 41. The sensor unit 4 detects the distance to the leaf spring 6 based on the arrival time of the reflected light when the light receiving element 42 receives the light reflected by the leaf spring 6 of the light emitted from the light emitting element 41, and the detection result is obtained. It outputs to the control part 5 as vibration information. In addition, the distance to the leaf spring 7 may be detected by making the sensor unit 4 face one main surface of the leaf spring 7.

  The control unit 5 calculates the operation speed of the movable member 9 based on the vibration information sent from the sensor unit 4, that is, the position information of the leaf spring 6, and emits a control signal corresponding to the calculated operation speed. Output to the element 2 and the coil 12, respectively.

  Hereinafter, the configuration of the actuator 3 will be described in more detail. As shown in FIG. 3, the leaf springs 6 and 7 are gradually narrowed from the proximal end portion toward the distal end portion. Further, the leaf springs 6 and 7 are arranged in parallel so that their main surfaces pass through the same plane and the longitudinal directions thereof are parallel to each other in an initial state where each of the leaf springs 6 and 7 is not bent (the state shown in FIG. 1 and the like). Is arranged.

  At the base end portion of the leaf spring 6, an electrode terminal portion 61 that protrudes from the base end portion along the longitudinal direction of the leaf spring 6 and attaches a wiring that connects to the control portion 5 is provided. Further, the tip of the leaf spring 6 is cut out in a direction substantially perpendicular to the longitudinal direction of the leaf spring 6, and one end of a winding (indicated by a broken line) of the coil 12 is hooked to energize the coil 12. A notch portion 62 to be secured is provided. The leaf spring 7 also has an electrode terminal portion 71 and a notch portion 72, similarly to the leaf spring 6. The leaf springs 6 and 7 are made of a spring material such as beryllium copper, phosphor bronze, or stainless steel, and are formed by stamping or press forming by pressing.

  The leaf springs 6 and 7 are connected to the control unit 5 through the electrode terminal units 61 and 71, respectively, and are connected to the windings of the coil 12 through the cutout units 62 and 72, respectively. In such a configuration, since the leaf springs 6 and 7 form part of the wiring, the circuit structure for energizing the coil can be simplified.

  The fixed member 8 and the movable member 9 are formed by injection molding an engineering plastic such as a liquid crystal polymer (LCP) or polyphenylene sulfide (PPS) filled with a glass fiber having a light weight and high rigidity. In addition, it is also possible to integrally mold the fixed member 8 and the movable member 9 by using the leaf springs 6 and 7 as insert materials.

  The movable member 9 has a frame member 91 that fixes the distal ends of the leaf springs 6 and 7 and also fixes the coil 12, and a thin plate-like light emitting element that is provided at the distal end of the frame member 91 and to which the light emitting element 2 is fixed. And a fixing member 92. The movable member 9 is realized using a light metal such as synthetic resin or aluminum. The frame member 91 includes leaf spring attachment portions 911 and 912 for attaching the tip portions of the leaf springs 6 and 7, respectively, a support portion 913 for supporting the light emitting element fixing member 92, and a coil holding portion for placing and holding the coil 12. 914. The main surface of the light emitting element fixing member 92 is orthogonal to the main surface of the leaf springs 6 and 7 in the initial state.

  The yoke 11 has a semi-annular surface similar to the main surface of the magnet 10, and two arc-shaped portions 111, 112 facing each other in a state where the surfaces are parallel and spaced apart, and the arc-shaped portion 111. , 112 are connected to each other, and two connecting portions 113 that connect the opposing end portions to each other. As shown in FIGS. 1 and 3, the magnet 10 is fixed to the surface of the arc-shaped portion 112 facing the arc-shaped portion 111 in a stacked state. The connecting portion 113 is fixed to the base member 14 via the screw member 13. The yoke 11 having the above configuration is made of a soft magnetic material such as pure iron.

  The opening surface of the coil 12 is substantially isosceles trapezoidal, and the short side is positioned on the inner peripheral side of the arc-shaped portions 111 and 112 of the yoke 11, while the long side is positioned on the outer peripheral side of the arc-shaped portions 111 and 112. is doing. Further, the coil 12 has a flat shape in which the length of the conductive wire in the winding direction (direction orthogonal to the opening surface) is smaller than the minimum diameter of the opening surface. The coil 12 having the above configuration has an opening surface located at a position where the opening surface is orthogonal to the stacking direction of the magnet 10 and the yoke 11, and is disposed in the gap between the magnet 10 and the arcuate portion 111. In the first embodiment, the coil 12 may be fixed to the base member 14 and the magnet 10 and the yoke 11 may be attached to the movable member 9.

  The magnet 10, the yoke 11, and the coil 12 constitute at least a part of a driving unit that drives the movable member 9 by an electromagnetic force generated by a current flowing through the coil 12.

4 and 5 are diagrams for explaining the operation of the light irradiation apparatus 1 having the above-described configuration, and showing a state in which the movable member 9 is located at the end point of vibration. In these drawings, it is orthogonal to the extending direction of the leaf springs 6 and 7 in the initial state (the left-right direction in FIG. 4), the origin is the intersection point with the extending direction of the leaf springs 6 and 7 in the initial state, and The coordinate axis with positive upward is the x axis. Further, the x coordinate of the vibration end point is set to ± x ₀ (x ₀ > 0). The movable member 9 performs simple vibration that reciprocates the end points of vibration illustrated in FIGS. 4 and 5.

Hereinafter, the position of the movable member 9 on the x-axis in FIGS. 4 and 5 is a function of time.
x (t) = x ₀ sin (ωt) (1)
It shall be represented by Here, ω in the equation (1) is an angular frequency when a system including the leaf springs 6 and 7 and the movable member 9 resonates. In this case, the control unit 5 determines the intensity P (t) of light emitted from the light emitting element 2 as follows.
P (t) = A | dx (t) / dt | + B
= Aωx ₀ | cos (ωt) | + B (2)
Control is performed. Here, the constants A and B in Expression (2) are positive numbers. As apparent from the equation (2), the light intensity P (t) is linearly related to the magnitude of the operation speed of the movable member 9 | dx (t) / dt |.

FIG. 6 is a diagram illustrating temporal changes in the positions x (t) and P (t). In FIG. 6, T is the period of vibration of the system composed of the leaf springs 6 and 7 and the movable member 9. According to FIG. 6 and equations (1) and (2), the light intensity P (t) takes the maximum value Aωx ₀₋ + B at the center of vibration (x = 0), while the end point (x = The minimum value B is taken at ± x ₀ ).

  As described above, in the first embodiment of the present invention, the greater the operation speed of the movable member, the greater the intensity of the light emitted from the light emitting means attached to the movable member of the actuator. While suppressing an increase in power consumption, it is possible to irradiate light with a substantially uniform intensity to a predetermined region.

  The intensity P (t) of the light emitted from the light emitting element 2 at time t only needs to have a smaller value as the absolute value of the position x (t) increases. For example, the time represented by a triangular wave It may be a function of

  Also, by attaching a strain gauge, a lead zirconate titanate (PZT) thin film, or a contact switch to the main surface of the leaf spring 6 or 7, the deformation amount of the leaf spring 6 or 7 from the initial state is vibrated. May be detected.

(Embodiment 2)
The second embodiment of the present invention is characterized in that a correction corresponding to the distance in the optical axis direction from the light emitting element to the irradiation region is added to the intensity of light emitted from the light emitting element.

  FIG. 7 is a diagram showing a configuration of a light irradiation apparatus according to Embodiment 2 of the present invention. In addition to the configuration of the light irradiation device 1 according to the first embodiment described above, the light irradiation device 15 shown in the figure includes irradiation region information including the distance in the optical axis direction of the light emitting element 2 from the light emitting element 2 to the irradiation region. Is provided with an irradiation area information storage unit 16.

FIG. 8 is a diagram schematically illustrating an example of setting the irradiation region of the light emitting element 2. Specifically, in FIG. 8, the distances in the optical axis direction of the light emitting element 2 to the end points Q ₁ and Q ₂ of the irradiation region S ₀ provided on the irradiation surface S forming a plane are r ₁ and r ₂ , respectively. Shows the case. In the case shown in FIG. 8, the distance r (hereinafter referred to as distance r) in the optical axis direction of the light emitting element 2 from the light emitting element 2 to the irradiation region S ₀ changes with time.

In the situation shown in FIG. 8, the control unit 5 performs correction by multiplying the intensity P (t) of the equation (2) by the square of the distance r at time t as the light intensity P (t, r). . That is, the light intensity P (t, r) is
P (t, r) = C · r ² · P (t) (3)
Given in. Here, the coefficient C is a positive constant. The distance r is a function r (x (t)) of x (t), and r (x ₀ ) = r ₁ and r (−x ₀ ) = r ₂ . This function r (x (t)) is stored in the irradiation area information storage unit 16 as irradiation area information. From the equation (3), the intensity ratio at the end points Q ₁ and Q ₂ of the irradiation region S ₀ is
P (t, r ₁ ) / P (t, r ₂ ) = r ₁ ² / r ₂ ² (4)
It is. In the equation (4), the value of the light intensity P (t) at the vibration end point (x = ± x ₀ ) is B (see FIG. 6).

In this way, in the second embodiment of the present invention, correction according to the distance r is added, so even if the distance r changes with time t, the irradiation area S _{0 is} almost equal. It is possible to irradiate light with uniform intensity.

By the way, the light irradiation device 15 can also be applied to an imaging system that images a predetermined region in order to monitor an object, for example. FIG. 9 is a diagram illustrating a configuration of the imaging system according to the second embodiment. The imaging system 17 shown in the figure includes a light irradiation device 15, an imaging device 18 that captures an image of a subject and generates image data, a display device 19 that displays an image corresponding to the image data generated by the imaging device 18, and Is provided. In FIG. 9, the irradiation area S ₀ of the light irradiation device 15 is set so as to include the angle of view of the imaging device 18.

  The display device 19 includes an image processing unit 191 that performs predetermined image processing on an image captured by the imaging device 18, and a display unit 192 that displays an image that has been subjected to predetermined image processing by the image processing unit 191. As a function of the image processing unit 191, for example, an object detection function for detecting whether or not a predetermined object is included in the image can be provided. In this case, the detected object may be displayed with emphasis on the display unit 192.

According to the imaging system 17 according to the second embodiment described above, since the irradiation area of the light emitting element 2 is configured to include the angle of view of the imaging device 18, an image captured by the imaging device 18 is displayed on the display device. when displaying 19 can acquire and display unevenness in brightness is small image of the irradiated area S _0.

  Further, according to the imaging system 17, when the image processing unit 191 of the display device 19 has an object detection function, it is possible to improve the accuracy of object detection by a good illumination state by the light emitting element 2.

  In addition, it is also possible to configure the imaging system by applying the light irradiation device 1 according to Embodiment 1 described above instead of the light irradiation device 15.

(Embodiment 3)
FIG. 10 is a diagram showing a configuration of a light irradiation apparatus according to Embodiment 3 of the present invention. The light irradiation device 20 shown in the figure includes a light emitting element 2, an actuator 21 having a movable member that vibrates together with the light emitting element 2, a vibration information acquisition unit 22 that acquires vibration information of the movable member of the actuator 21, and vibration information acquisition. The control part 23 which controls operation | movement of the light emitting element 2 and the actuator 21 based on the result which the part 22 acquired is provided.

  The actuator 21 is provided in the center of the torsion bar 24 with the torsion bar 24, two fixing members 25a and 25b for fixing both ends of the torsion bar 24, and the light emitting element 2 attached to the surface. A thin flat plate-shaped movable member 26 that rotates in accordance with the torsion 24 and a drive unit 27 that drives the movable member 26 are provided. The torsion bar 24 is made of the same spring material as the leaf spring 6 and the like described above. The drive unit 27 may be configured to drive the movable member 26 by appropriately combining a magnet, a yoke, and a coil, or may be configured to drive the movable member 26 by directly rotating the torsion bar 24.

  Two independent torsion bars may be provided between the fixed member 25 a and the movable member 26 and between the fixed member 25 b and the movable member 26.

  The details of the control performed by the light irradiation apparatus 20 having the above configuration are the same as the control performed by the light irradiation apparatus 1 or 15 described above.

  According to the third embodiment of the present invention described above, the intensity of light emitted from the light emitting element 2 attached to the movable member 26 is controlled to increase as the operating speed of the movable member 26 increases. While suppressing an increase in power consumption, it is possible to irradiate light with a substantially uniform intensity to a predetermined region.

  Up to this point, the first to third embodiments have been described as modes for carrying out the present invention. However, the present invention should not be limited to the three embodiments described above.

  For example, in the present invention, the vibration information acquisition means may be configured by using a magnetic sensor having a Hall element or a search coil. The vibration information in this case is an induced electromotive force generated in the coil 12 measured by the magnetic sensor. Therefore, the control unit 5 can calculate the magnitude of the operation speed of the movable member 9 from the induced electromotive force by a predetermined calculation.

  In the present invention, it is also possible to apply an actuator having a configuration different from that of the actuator 3 described above.

  INDUSTRIAL APPLICABILITY The present invention is useful for all products that irradiate visible light or infrared light, and is particularly suitable as an automobile surveillance camera that captures an image of an irradiation range and captures an image, a surveillance camera for security, or a wide range of illumination. .

DESCRIPTION OF SYMBOLS 1, 15, 20 Light irradiation apparatus 2, 41 Light emitting element 3, 21 Actuator 4 Sensor part 5, 23 Control part 6, 7 Leaf spring 8, 25a, 25b Fixed member 9 Movable member 10 Magnet 11 York 12 Coil 13 Screw member 14 Base member 16 Irradiation region information storage unit 17 Imaging system 18 Imaging device 19 Display device 22 Vibration information acquisition unit 24 Torsion bar 26 Movable member 27 Drive unit 42 Light receiving element 191 Image processing unit 192 Display unit S Irradiation surface S ₀ Irradiation region

Claims (10)

An actuator having an elastic member, a movable member attached to the elastic member and vibrating while being restrained by the elastic member, and a driving means for driving the movable member;
A light emitting means attached to the movable member and emitting light of a predetermined frequency;
Vibration information acquisition means for acquiring information related to vibration of the movable member;
Control means for performing control to increase the intensity of the light emitted by the light emitting means as the magnitude of the operation speed of the movable member determined based on the vibration information acquired by the vibration information acquiring means increases;
A light irradiation apparatus comprising:   The light irradiation apparatus according to claim 1, wherein the intensity of the light has a linear relationship with the magnitude of the operation speed of the movable member. The control means includes
The light irradiation apparatus according to claim 1, wherein the light intensity is corrected according to a distance in the optical axis direction of the light emitting unit from the light emitting unit to a predetermined irradiation surface. The driving means includes
A magnet,
A coil located in the vicinity of the magnet;
Have
Either one of the said magnet and the said coil is attached to the said movable member, The light irradiation apparatus as described in any one of Claims 1-3 characterized by the above-mentioned.   The light irradiation apparatus according to claim 4, wherein the vibration information is information related to an induced electromotive force accompanying a change in magnetic flux crossing the coil.   The light irradiation apparatus according to claim 1, wherein the vibration information is information related to a position of the elastic member.   The light irradiation apparatus according to claim 1, wherein the light is visible light or infrared light.   The light irradiation apparatus according to claim 1, wherein the elastic member is a leaf spring.   The light irradiation apparatus according to claim 1, wherein the elastic member is a torsion bar. The light irradiation device according to any one of claims 1 to 9,
An imaging device having an angle of view included in an area irradiated with the light by the light emitting means and imaging the subject to generate image data;
A display device for displaying an image corresponding to the image data generated by the imaging device;
An imaging system comprising:

Images