JP2008066203A - Lighting device and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device with high light utilization efficiency capable of preventing members arranged around a light source such as an optical member from being deformed, discolorated, and damaged due to the heat radiation of the light source. <P>SOLUTION: The lighting device 30 is provided with a light source 31, an optical member 32 at least transmitting and irradiating light flux incident from the light source, and a translucent member 35 arranged between the light source and the optical member and having an incident face and an irradiation face each having a curved surface coaxial with the light source. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illumination device used for an imaging device or the like.

  Illumination devices used for flash photography include a built-in flash device built into the camera like a so-called compact camera and an external flash device that can be attached to a single-lens reflex camera or a video camera.

  Some external flash devices have a large light quantity such that the guide number exceeds 40. Such an external flash device uses a capacitor exceeding 1000 μF, and generates a large amount of heat as well as a large amount of light. Also, in order to shorten the interval between flash photography and improve usability, it is necessary to shorten the capacitor charging time.

  Due to the trend toward miniaturization of cameras, there is a demand for miniaturization of flash devices built in or externally attached to the camera. Therefore, a light-emitting discharge tube that is a light source, a reflector that reflects light emitted from the light-emitting discharge tube to the opposite side of the subject to the front (subject side), and an optical member provided in front of the discharge tube; But they are getting closer to each other.

  In addition, various techniques for illumination devices that efficiently collect light beams emitted from various directions in a light source within a required irradiation angle of view have been proposed. For example, in place of the conventionally used Fresnel lens, there is an optical member that utilizes total reflection such as a prism or a light guide to improve the light collection efficiency and reduce the size (for example, patents). Reference 1).

  The optical member as described above often has a complicated shape, and is often formed of a resin material such as an acrylic resin having good moldability.

  However, when flash emission is frequently performed, the discharge tube may be discolored or deteriorated due to heat generated from the light-emitting discharge tube, or an optical member such as a prism may be discolored or melted. Furthermore, since the exit surface of the optical member often constitutes the appearance of a camera or flash device, when the optical member becomes hot, it may cause discomfort to the user, or the exterior member of the camera or flash device may be deformed or discolored. May occur. This problem becomes more pronounced when the capacitor charging time is shortened and faster continuous shooting is possible.

  Therefore, Patent Document 2 discloses an illumination device that emits a light beam from a light source as light in a predetermined irradiation angle range through an optical member, and the optical member is composed of two members of different materials, An illuminating device in which a member is formed of an optical material having high heat resistance has been proposed.

  Furthermore, since the light emitted from the light emitting discharge tube includes infrared rays, there is a possibility that thermal damage may occur due to the optical member being burned or melted by the irradiation of the infrared rays.

Therefore, Patent Document 3 proposes an illumination device in which a ceramic-based coating (optical thin film) is applied to the vicinity of a light source of an optical member for heat resistance and infrared cut.
JP 2001-264859 A (paragraph 0026, FIG. 3 etc.) JP-A-11-242273 (paragraph 0059, FIG. 7 etc.) JP 2001-005063 A (paragraphs 0021 to 0024, FIG. 1, etc.)

  There are the following three types of heat transfer.

  1. Radiation: Heat is transmitted by electromagnetic waves emitted directly from an object with temperature.

  2. Conduction: Heat is transferred by the temperature difference in the thickness direction between the front and back of an object.

  3. Convection: Heat is transferred by continuous movement of fluid (air).

  Usually, in flash light emission, heat generated from the light emitting discharge tube becomes radiant heat and is transmitted to the optical member.

  However, when the light emitting discharge tube emits light continuously, the air around the discharge tube is warmed and a convection phenomenon occurs. And the heat which reached the surface of the optical member is transmitted to the whole optical member by a conduction phenomenon, and raises the temperature of the optical member.

  For this reason, the optical member disclosed in Patent Document 2 is made of an optical material having high heat resistance, and the optical member is made of two members having different materials, or the ceramic coating disclosed in Patent Document 3 is applied. However, it is impossible to prevent heat from being transmitted to the entire optical member.

  Therefore, even if the protective layer is provided on the light source side of the optical member, the optical member itself may be softened if the temperature of the optical member itself gradually increases and becomes overheated. Further, the optical member may be peeled off from the heat-resistant member or the coating.

  An object of the present invention is to provide a lighting device that can prevent deformation, discoloration, and damage of members arranged around a light source such as an optical member caused by heat generation of the light source and that has high light use efficiency. It is said.

  An illumination device according to one aspect of the present invention is disposed between a light source, an optical member that transmits at least a light beam incident from the light source, and is emitted between the light source and the optical member, and has a curved surface shape concentric with the light source. And a translucent member having an entrance surface and an exit surface.

  Note that an imaging system including the imaging device having the illumination device or an imaging device to which the illumination device is attached / detached also constitutes another aspect of the present invention.

  According to the present invention, a translucent wall is formed around the light source by the translucent member, so that the direction of heat convection can be controlled and the conduction of heat to the optical member can be suppressed. Therefore, it is possible to realize a lighting device that can prevent deformation, discoloration, and damage of the light source and the optical member due to heat generation of the light source, and can secure high light use efficiency.

  And if this illuminating device is used for an imaging device, it is possible to perform imaging with a large amount of flash emission at high speed and continuously.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  1 to 6 show a configuration of an imaging system including an illumination apparatus that is Embodiment 1 of the present invention and an imaging apparatus to which the illumination apparatus is detachably mounted.

  In FIG. 1, reference numeral 1 denotes a single-lens reflex camera (hereinafter simply referred to as a camera) as an imaging device, and a photographing lens (interchangeable lens) 11 is attached to the front surface (surface on the subject side).

  In the camera 1, optical parts, mechanical parts, electrical parts and films, or image sensors such as CCD sensors or CMOS sensors are housed.

  Reference numeral 2 denotes a main mirror, which is obliquely installed in the photographing optical path in the viewfinder observation state and retracts out of the photographing optical path in the photographing state. The main mirror 2 is a half mirror. When the main mirror 2 is inclined in the photographing optical path, approximately half of the light beam from the subject is transmitted through the focus detection optical system.

  Reference numeral 3 denotes a focus plate disposed on the planned imaging surface of the photographing lens 11 constituting the finder optical system, and reference numeral 4 denotes a pentaprism for changing the finder optical path.

  Reference numeral 5 denotes an eyepiece lens, and the photographer can observe the photographing screen by observing the focus plate 3 from a window near the eyepiece lens 5.

  Reference numerals 6 and 7 denote an imaging lens and a photometric sensor for measuring the subject brightness within the viewfinder observation angle of view, and the imaging lens 6 connects the focusing plate 3 and the photometric sensor 7 via the reflected light path in the pentaprism 4. It is related to conjugation.

  Reference numeral 8 denotes a focal plane shutter, and 9 denotes a photosensitive member, which is a silver salt film or an image sensor.

  Reference numeral 25 denotes a sub-mirror which, like the main mirror 2, is inclined in the photographing optical path in the viewfinder observation state and retracts out of the photographing optical path in the photographing state. The sub-mirror 25 bends the light beam transmitted through the oblique main mirror 2 and guides it toward the focus detection unit 26.

  The focus unit 26 includes a secondary imaging mirror 27, a secondary imaging lens 28, a focus detection line sensor 29, and the like. The secondary imaging mirror 27 and the secondary imaging lens 28 constitute a focus detection optical system, and the secondary imaging surface of the photographing lens 11 is formed on the focus detection line sensor 29. The focus detection unit 26 detects the focus state of the photographing lens 11 by a phase difference detection method or the like, and outputs the detection result to a focus control circuit (not shown) that performs focus control of the photographing lens 11.

  The camera 1 and the photographic lens 11 can communicate with each other via a lens mount contact group (not shown).

  In the photographic lens 11, reference numerals 12 to 14 denote lenses, and 15 denotes an aperture. The first lens 12 is a focus lens that adjusts the focus by moving back and forth on the optical axis. The second lens 13 is a zoom lens that performs zooming by moving back and forth on the optical axis. The third lens 14 is a fixed lens.

  Reference numeral 16 denotes a focus drive motor that moves the first lens 12 in the optical axis direction. Reference numeral 17 denotes an aperture drive motor that drives the aperture 15 so as to change the aperture diameter. The position of the first lens 12 is detected by an encoder (not shown).

  Further, the second lens 13 is provided with a position detector (not shown), and by obtaining focal length information obtained from the position of the second lens 13 and focus position information obtained from the position of the first lens 12. The subject distance can be obtained.

  Reference numeral 30 denotes an illumination device that can be attached to and detached from the camera 1, and performs light emission control according to a signal from the camera 1.

  In the illumination device 30, reference numeral 31 denotes a cylindrical light emitting discharge tube (xenon tube: hereinafter referred to as a light emitting tube) that emits flash light, and converts current energy supplied from a capacitor (not shown) into light emitting energy. Reference numeral 32 denotes a first optical member disposed in front of the arc tube 31 (subject side). Reference numeral 33 denotes a second optical member that configures the appearance of the illumination device 30 and forms an exit window for light from the arc tube 31.

  Reference numeral 34 denotes a reflecting mirror (reflecting umbrella) disposed behind the arc tube 31. Reference numeral 35 denotes a cylindrical light transmitting member disposed between the arc tube 31 and the first optical member 32. The translucent member 35 is for protecting the first optical member 32 and the like from thermal damage caused by heat generation of the arc tube 31.

  By the action of these optical components, the light from the arc tube 31 can be efficiently focused toward the subject.

  Reference numeral 50 denotes a contact group provided on a hot shoe serving as a communication interface between the camera 1 and the illumination device 30.

  In addition, since each function except the optical system of the illuminating device 30 is a well-known technique, detailed description is abbreviate | omitted here. In addition, the mechanical component of this invention is not limited to what was mentioned above.

  FIG. 2 is a perspective view of the main components of the lighting device 30 according to the present embodiment as viewed from the front, and FIG. 3 is an exploded perspective view of the main components of the lighting device 30 as viewed from the front. Hereinafter, the components of the illumination device 30 will be described in more detail with reference to FIGS. 2 and 3.

  The arc tube 31 includes a cylindrical glass tube portion 31a serving as a light emitting portion, and terminal portions 31b provided at both ends of the glass tube portion 31a.

  The first optical member 32 divides the luminous flux from the arc tube 31 into several luminous fluxes, and each divided luminous flux exits from the exit surface and intersects at a certain distance, thereby providing a specific light distribution characteristic. It converts into the light beam which has.

  The second optical member 33 converts the light beam incident from the first optical member 32 into a light beam having a required light distribution characteristic. On the incident surface of the second optical member 33, a plurality of cylindrical lens portions are formed in the vertical direction. In addition, a Fresnel lens portion having a light collecting function in the left-right direction (longitudinal direction of the arc tube 31) is formed on the exit surface. The first and second optical members 32 and 33 are made of an optical resin material or glass material having a high transmittance such as an acrylic resin.

  Reference numeral 34 denotes a reflector that reflects the light beam emitted rearward from the arc tube 31 forward. The reflector 34 is formed of a metal material such as bright aluminum whose inner surface has a high reflectance, or is formed of a member in which a metal deposition surface having a high reflectance is formed on the inner surface.

  The translucent member 35 has a cylindrical inner surface (incident surface) and outer surface (exit surface) concentric with the radial center of the arc tube 31 (glass tube portion 31a). The translucent member 35 is provided in order to prevent the first optical member 32 and the like from being thermally damaged by the surrounding gas (air) heated by the continuous light emission of the arc tube 31 or the like. Specifically, the convection direction of the warmed air is controlled. Here, the translucent member 35 is formed of a heat-resistant material such as highly transparent glass or transmissive ceramic.

  In addition, an infrared reflective coating layer that reflects heat rays (infrared rays) is formed on at least one of the inner surface and the outer surface of the translucent member 35. This makes it difficult for radiant heat to be transmitted to the first optical member 32. In addition, you may use heat ray absorption glass for the material of the translucent member 35. FIG.

  Reference numeral 40 denotes a holding case that holds the first optical member 32 fixed by adhesion or the like.

  A rubber band 41 is hung on both ends of the translucent member 35 and pulls the translucent member 35 rearward. The rubber band 41 holds the translucent member 35 and the reflective umbrella 34 in contact with the translucent member 35 in the holding case 40. The rubber band 41 is made of heat-resistant silicon rubber or the like.

  Reference numerals 42a and 42b denote arc tube holding members, which are fixed to the holding case 40 by screws 43a and 43b. A lead wire (not shown) extending from an electric circuit board (not shown) is connected to the terminal portion 31 b of the arc tube 31. In addition, a trigger line (not shown) is connected to the glass tube portion 31a.

  With this configuration, the arc tube 31, the first optical member 32, the reflector 34, and the translucent member 35 can be integrated with the holding case 40. Then, by changing the distance between the first optical member 32 and the second optical member 33, the light collection degree can be continuously changed.

  In the camera 1, for example, when “flash auto mode” is set, when a release button (not shown) is half-pressed by the user, the brightness of external light is measured (photometric) by a photometry circuit (not shown). The This photometric result is sent to a central processing unit (not shown) arranged in the camera 1. The central processing unit determines whether or not to cause the illumination device 30 to emit light according to the brightness of external light and the sensitivity of the photosensitive member 9.

  When it is determined that the lighting device 30 is caused to emit light, the central processing unit outputs a light emission signal to the lighting device 30 in response to a full press operation of the release button. Thereby, the arc tube 31 emits light.

  Of the luminous flux emitted from the arc tube 31, the luminous flux directed backward is reflected by the reflector 34 and guided forward. The light beam emitted forward from the arc tube 31 is transmitted through the translucent member 35 and converted into a specific light distribution characteristic through the first optical member 32 and the second optical member 33 disposed in front. To the subject side.

  As will be described later, the illuminating device 30 of the present embodiment mainly includes internal components such as the first and second optical members 32 and 33 disposed in front of the arc tube 31 and the holding case 40, and the illuminating device 30 ( Or it has the structure which does not give thermal damage to the exterior member of the camera 1).

  As described above, the first and second optical members 32 and 33 can change the relative position in the irradiation optical axis direction, and thereby the irradiation angle range of the light beam (illumination light beam) emitted from the illumination device 30 can be changed. Can be changed. Relative driving of the first and second optical members 32 and 33 is performed by a driving mechanism (not shown). This driving mechanism is linked to a zoom driving mechanism that performs zoom driving of the photographing lens 11. With this configuration, the irradiation angle range in the illumination device can be changed according to zooming of the photographing lens 11.

  Hereinafter, the shape of the optical system (illumination optical system) of the illumination device 30 and the behavior of light rays emitted from the arc tube 31 will be described in detail.

  4 and 5 are cross-sectional views in which the illumination device 30 is cut in the radial direction of the arc tube 31 along the irradiation optical axis AXL.

  FIG. 4 shows the arrangement of the optical members 32 and 33 in the state where the light flux emitted from the arc tube 31 is most converged, that is, in the state where the irradiation angle range is the narrowest. FIG. 5 shows the arrangement of the optical members 32 and 33 in a state where the light beam emitted from the arc tube 31 is uniformly diverged, that is, in a state where the irradiation angle range is the widest. Here, in FIGS. 4 and 5, trace diagrams of representative rays (representative rays) emitted from the center of the arc tube 31 are appended.

  4 and 5 show the inner and outer diameters of the glass tube portion 31 a as the arc tube 31. As the light emission phenomenon of the arc tube 31, it is often the case that light is emitted to the entire inner diameter in order to improve the light emission efficiency, and it can be considered that light is emitted almost uniformly to the entire inner diameter of the arc tube 31. On the other hand, in the design stage, in order to efficiently control the light emitted from the arc tube 31, it is assumed that there is a point light source ideally at the center of the light source, rather than considering the luminous flux of the entire inner diameter of the arc tube 31 at the same time. It is preferable to design the shape of the illumination optical system.

  Then, after designing the shape of the illumination optical system, it is possible to design efficiently by performing correction considering that the light source has a finite size.

  Also in this embodiment, based on the above-described concept, the center of the light emitting portion of the light source is used as a reference when determining the shape of the illumination optical system, and the shape of each optical member is set as described below.

  First, the first optical member 32 is a prism-like member. As shown in FIGS. 4 and 5, the first optical member 32 is disposed in front of the arc tube 31 with a planar incident surface 32 </ b> C disposed above and below the arc tube 31, and the longitudinal direction of the arc tube 31. And a cylindrical lens surface 32R which is an incident surface having a converging function. Moreover, it has the reflective surface 32TR arrange | positioned above and below the entrance plane 32C, and the exit surface arrange | positioned ahead of the cylindrical lens surface 32R and the up-and-down reflective surface 32TR.

  A plurality of cylindrical lens portions 32N each having a predetermined vertical width and having a diverging action in the vertical direction are formed on the exit surface of the first optical member 32 so as to extend in the longitudinal direction of the arc tube 31.

  On the incident surface of the second optical member 33, a plurality of cylindrical lens portions 33R each having a predetermined vertical width and having a diverging action in the vertical direction are formed so as to extend in the longitudinal direction of the arc tube 31. On the exit surface of the second optical member 33, a Fresnel lens portion having a condensing function in the longitudinal direction of the arc tube 31 is formed.

  Next, the behavior of light rays in an actual illumination optical system will be described with reference to the ray trace diagrams shown in FIGS.

  In FIG. 4, a light beam emitted from the arc tube 31 to the right side (subject side) of the drawing passes through the translucent member 35. Since the translucent member 35 has a cylindrical shape that is concentric with the arc tube 31, the light beam that passes through the translucent member 35 is hardly refracted. O represents the radial center of the arc tube 31 (glass tube portion 31a) (hereinafter also referred to as the light source center).

  Of the light rays emitted from the arc tube 31 to the right side of the figure, the light rays emitted upward and downward at an angle larger than the first angle with respect to the irradiation optical axis AXL are incident surfaces 32C of the first optical member 32. After being refracted, the light is substantially totally reflected by the reflecting surface 32TR. Thereby, it becomes a light ray parallel to the irradiation optical axis AXL. Thereafter, the light beam is refracted by the cylindrical lens portion 32N, and is emitted as a divergent light beam passing through one point (however, a region having a specific size, the same applies hereinafter).

  Of the light rays emitted from the arc tube 31 to the right side of the drawing, the light rays emitted upward and downward at an angle smaller than the first angle with respect to the irradiation optical axis AXL are cylindrically generated by the first optical member 32. The light is refracted by the lens portion 32R and becomes a light ray parallel to the irradiation optical axis AXL. Thereafter, the light is refracted by the cylindrical lens portion 32N on the exit surface, and emitted as a divergent ray passing through one point.

  Then, the light beam emitted from the cylindrical lens portion 32N provided on the emission surface of the first optical member 32 is incident on the cylindrical lens portion 33R on the incident surface of the second optical member 33. Then, the light is refracted by the cylindrical lens portion 33N, becomes a light beam parallel to the irradiation optical axis AXL, and is emitted from the second optical member 33 toward the subject side with a narrow light distribution angle.

  On the other hand, in FIG. 5, the light beam emitted from the arc tube 31 to the right side (subject side) of the drawing passes through the translucent member 35. Also at this time, as described above, the light beam is transmitted without being refracted by the translucent member 35.

  Among the light rays emitted from the arc tube 31 to the right side of the drawing, the light rays emitted upward and downward at an angle larger and smaller than the first angle with respect to the irradiation optical axis AXL, respectively, as in FIG. The light is emitted from the cylindrical lens portion 32N of the first optical member 32.

  Then, the light beam emitted from the cylindrical lens portion 32N so as to converge at one point is incident on the cylindrical lens 33R on the incident surface of the second optical member 33, and a wide light distribution from the second optical member 33 remains divergent light. Ejected to the subject side at an angle.

  4 and 5 show a state where the irradiation angle range is the narrowest and the widest, respectively. However, the illumination device 30 according to the present embodiment continuously changes the irradiation angle range between the two states by changing the relative positions of the first and second optical members 32 and 33, that is, zooming. It can be performed.

  On the other hand, although not shown in the drawing, the optical path of the light beam traveling behind the arc tube 31 will be described. A reflector 34 having a semicylindrical shape concentric with the light source center O is provided behind the arc tube 31. Further, since the glass tube portion 31a of the arc tube 31 also has a cylindrical shape with the light source center O as the center, all the light beams emitted backward from the light source center O are not affected by the refraction by the glass tube portion 31a, and again the light source center Come back to O. The light beam after returning to the light source center O behaves in the same manner as the light beam emitted forward shown in FIGS.

  FIG. 6 shows an enlarged view around the arc tube 31. In FIG. 6, reference numeral 36 denotes a thermal conductive material such as silicon goose, which is disposed between the reflector 34 and the translucent member 35 and has high adhesion and high conductivity. The thermally conductive material 36 is disposed at both ends in the longitudinal direction of the arc tube 31 so as not to block the light emission of the arc tube 31. The thermally conductive material 36 has a function of facilitating heat dissipation by making it easy to transfer heat generated when the arc tube 31 emits light to the reflector 34.

  Thus, in the present embodiment, the light distribution angle in the vertical direction can be changed by relatively moving the first optical member 32 and the second optical member 33. Therefore, if this illumination device 30 is attached to the camera 1 to which the zoomable photographing lens 11 is attached, and the first and second optical members 32 and 33 are relatively moved in conjunction with zooming of the photographing lens 11. Therefore, it is possible to always obtain an optimum irradiation angle range corresponding to the focal length of the photographing lens 11.

  Further, in this embodiment, the light transmitting member 35 made of optical glass, light transmitting ceramic or the like is used as a wall member for controlling the convection direction of air heated by heat from the arc tube 31 or preventing convection. Are arranged around the arc tube 31. As a result, deformation, discoloration, and breakage (including dissolution) of the arc tube 31 and the first optical member 32 and the exterior member of the lighting device 30 due to heat generation of the arc tube 31 can be prevented, and light utilization efficiency is high. The illumination device 30 can be realized.

  Moreover, since the translucent member 35 has a cylindrical shape that is concentric with the arc tube 31 and has a uniform thickness, the optical design is not complicated.

  7 to 10 show the configuration of a lighting apparatus that is Embodiment 2 of the present invention. FIG. 7 is a perspective view of the configuration of main parts of the lighting device according to the present embodiment as viewed from the front, and FIG. 8 is an exploded perspective view of the configuration of main components of the lighting device as viewed from the front.

  In the present embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

  Reference numeral 351 denotes a cylindrical translucent member concentric with the light source center of the arc tube 31. Reference numeral 401 denotes a holding case.

  Since the configuration of the illumination optical system and the behavior of the light beam in this embodiment are the same as those in the first embodiment, description thereof is omitted.

  9 and 10 are cross-sectional views of the illumination device of the present embodiment cut along the radial direction of the arc tube 31 along the irradiation optical axis AXL.

  A material having high reflectivity with respect to visible light is deposited or applied on the rear semi-cylindrical portion (in the drawing, the rear semi-cylindrical portion of the outer surface) of at least one of the inner surface and the outer surface of the translucent member 351 so that visible light is visible. A reflection surface (visible light reflection layer) 351a is formed. Here, the material having high reflectance is, for example, aluminum or silver. Further, a multilayer film structure in which the reflectance is improved by utilizing light interference may be used. The visible light reflecting surface 351a has the same function as the reflector used in the first embodiment. Therefore, in this embodiment, a reflector is not required, and the number of components of the illumination optical system can be reduced and the illumination device can be further downsized.

  In addition, at least one of the inner surface and the outer surface of the translucent member 351 reflects the infrared rays at the front semi-cylindrical portion (the portion different from the portion provided with the visible light reflecting surface 351a. An infrared reflective coating layer 351b is formed. This makes it difficult for radiant heat to be transmitted to the first optical member 32.

  In the drawing, the visible light reflection surface 351a and the infrared reflection coating layer 351b are shown thick for easy understanding, but they are actually very thin layers.

  As a material of the translucent member 351, heat ray absorbing glass may be used.

  Also in this embodiment, the light distribution angle in the vertical direction can be changed by relatively moving the first optical member 32 and the second optical member 33. Therefore, if this illuminating device is attached to the camera 1 to which the zoomable photographing lens 11 is attached and the first and second optical members 32 and 33 are relatively moved in conjunction with zooming of the photographing lens 11, An optimum irradiation angle range corresponding to the focal length of the photographic lens 11 can always be obtained.

  Furthermore, also in this embodiment, a light-transmitting member 351 made of optical glass or light-transmitting ceramic is used as a wall member for controlling the convection direction of air heated by heat from the arc tube 31 or preventing convection. Are arranged around the arc tube 31. As a result, deformation, discoloration, and breakage (including dissolution) of the arc tube 31 and the first optical member 32 and the exterior member of the lighting device 30 due to heat generation of the arc tube 31 can be prevented, and light utilization efficiency is high. A lighting device can be realized.

  Moreover, since the translucent member 351 has a cylindrical shape that is concentric with the arc tube 31 and has a uniform thickness, the optical design is not complicated.

  11 to 15 show the configuration of a lighting apparatus that is Embodiment 3 of the present invention. FIG. 11 is a perspective view of the configuration of main parts of the lighting device of the present embodiment as viewed from the front, and FIG. 12 is an exploded perspective view of the configuration of main components of the lighting device of the present embodiment as viewed from the front.

  In the present embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

  Reference numeral 342 denotes a reflector, and reference numeral 352 denotes a translucent member having a semi-cylindrical shape (partial cylindrical shape) concentric with the light source center of the arc tube 31. Reference numeral 402 denotes a holding case.

  The reflection umbrella 342 is provided with anti-rotation portions 342a and 342b at both ends for preventing the translucent member 352 from rotating about the longitudinal axis.

  Since the configuration of the illumination optical system and the behavior of the light beam in this embodiment are the same as those in the first embodiment, description thereof is omitted.

  13 and 14 are cross-sectional views of the illumination device of the present embodiment cut along the radial direction of the arc tube 31 along the irradiation optical axis AXL.

  At least one of the inner surface and the outer surface of the translucent member 352 is formed with an infrared reflective coating layer 352b that reflects infrared light. This makes it difficult for radiant heat to be transmitted to the first optical member 32.

  In the figure, the infrared reflective coating layer 352b is shown thick for easy understanding, but it is actually a very thin layer.

  As a material of the translucent member 352, heat ray absorbing glass may be used.

  In this embodiment, the translucent member 352 has a semi-cylindrical shape, and the reflector 342 can be disposed behind the arc tube 31 without the translucent member. As a result, the luminous flux from the arc tube 31 can be irradiated to the subject side with the same characteristics as in the first embodiment, and the illumination optical system and, hence, the illumination device can be miniaturized.

  In FIG. 15, the vicinity of the arc tube 31 is shown enlarged. In FIG. 15, reference numeral 362 denotes a thermal conductive material such as silicon goose that is disposed between the reflector 342 and the translucent member 352 and has high adhesion and high conductivity. The thermally conductive material 362 is disposed at both ends of the reflector 342 so as not to block the light emission of the arc tube 31. The heat conductive material 362 has a function of facilitating heat dissipation by making it easy to transfer heat generated when the arc tube 31 emits light to the reflector 342.

  Thus, in the present embodiment, the light distribution angle in the vertical direction can be changed by relatively moving the first optical member 32 and the second optical member 33. Therefore, if this illuminating device is attached to the camera 1 to which the zoomable photographing lens 11 is attached and the first and second optical members 32 and 33 are relatively moved in conjunction with zooming of the photographing lens 11, An optimum irradiation angle range corresponding to the focal length of the photographic lens 11 can always be obtained.

  Further, in this embodiment, a light transmissive member 352 made of optical glass, light transmissive ceramic or the like is used as a wall member for controlling the convection direction of air heated by heat from the arc tube 31 or preventing convection. Is arranged in the front part of the periphery of the arc tube 31. Thereby, deformation, discoloration, and breakage (including dissolution) of the arc tube 31 and the first optical member 32 and the exterior member of the lighting device due to heat generation of the arc tube 31 can be prevented, and illumination with high light use efficiency is achieved. A device can be realized.

  Moreover, since the translucent member 352 has a semi-cylindrical shape that is concentric with the arc tube 31 and has a uniform thickness, the optical design is not complicated.

  In the present embodiment, a translucent member having a semi-cylindrical shape is used as the partial semi-cylindrical shape, but it is larger (for example, 2/3 cylindrical shape) or smaller (for example, 1/3 cylindrical shape) than the semi-cylindrical shape. ) May be used.

  In each of the above embodiments, a so-called zoom flash is described as an example, but the present invention can also be applied to a fixed flash that does not have a zoom function.

  In each of the above embodiments, a case where an arc tube is used as a light source will be described. In this case, as the translucent member, one having an inner surface (incident surface) and an outer surface (exit surface) each having a spherical shape or a partial spherical shape concentric with the spherical portion of the light source may be used. Furthermore, although the translucent member is expressed as a curved surface shape concentric with the light source, the case where it is not completely concentric due to a manufacturing error, an assembly error, and the like is included. Further, the present invention can be applied not only to flash light but also to emitting steady light.

  Furthermore, the dimensions, materials, shapes, arrangements, and the like of the component parts described in the above embodiments are merely examples, and can be changed or modified.

1 is a cross-sectional view illustrating a configuration of an imaging system including an illumination device that is Embodiment 1 of the present invention. 1 is a perspective view of a lighting device according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view of the lighting device according to the first embodiment. Sectional drawing (tele state) of the illuminating device of Example 1. FIG. Sectional drawing (wide state) of the illuminating device of Example 1. FIG. FIG. 3 is an enlarged view of the vicinity of the arc tube in the illumination device of Example 1. The perspective view of the illuminating device which is Example 2 of this invention. FIG. 6 is an exploded perspective view of a lighting device according to a second embodiment. Sectional drawing of the illuminating device of Example 2 (tele state). Sectional drawing (wide state) of the illuminating device of Example 2. FIG. The perspective view of the illuminating device which is Example 3 of this invention. FIG. 6 is an exploded perspective view of a lighting device according to a third embodiment. Sectional drawing of the illuminating device of Example 3 (tele state). Sectional drawing (wide state) of the illuminating device of Example 3. FIG. FIG. 6 is an enlarged view around the arc tube in the illumination device of Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 11 Shooting lens 30 Illuminating device 31 Light emission tube 32 1st optical member 33 2nd optical member 34,342 Reflector umbrella 35,351,352 Light-transmitting member 36,362 Thermally conductive substance

Claims (12)

A light source;
An optical member that transmits and emits at least a light beam incident from the light source;
An illuminating device, comprising: a light-transmitting member that is disposed between the light source and the optical member, and includes an incident surface and an exit surface each having a curved surface shape concentric with the light source. The light source has a cylindrical portion for emitting a light beam,
The lighting device according to claim 1, wherein the translucent member has an entrance surface and an exit surface each having a cylindrical shape or a partial cylindrical shape concentric with the cylindrical portion of the light source. The light source has a spherical portion that emits a luminous flux,
The lighting device according to claim 1, wherein the translucent member has an entrance surface and an exit surface each having a spherical shape or a partial spherical shape concentric with the spherical portion of the light source. The translucent member has a portion opposite to the optical member with respect to the light source,
4. The illumination device according to claim 1, further comprising a reflecting member having a shape along an emission surface of the opposite side portion. 5.   The lighting device according to claim 4, wherein the reflection member is provided with a rotation preventing portion of the light transmissive member.   The lighting device according to claim 4, wherein the reflecting member holds the translucent member.   The illumination device according to claim 4, wherein a visible light reflection layer is formed on at least one of an incident surface and an emission surface in the opposite side portion of the translucent member.   The lighting device according to claim 4, wherein a heat conductive material is disposed between the translucent member and the reflecting member.   The illumination device according to claim 1, wherein an infrared reflection layer is formed on at least one of the incident surface and the emission surface of the light transmitting member.   The lighting device according to claim 1, wherein the translucent member is made of an infrared absorbing material.   An imaging apparatus comprising the illumination device according to claim 1. The lighting device according to any one of claims 1 to 10,
An imaging system comprising: an imaging device to which the illumination device is detachably attached.