JP2008216860A - Flash unit, camera, light source with light-quantity detecting sensor, and light source unit for the flash unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect the light quantity of a flash discharge tube, without being affected by external light. <P>SOLUTION: The flash unit is equipped with: a rod-like light source 311 whose prescribed axial direction is a longitudinal direction; a reflection member 300 reflecting light emitted from the light source 311 toward an object; and a detection means 313 detecting the quantity of the light for detecting the light quantity which is the light emitted in the prescribed axial direction, of the light emitted from the light source 311. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flash device for detecting the amount of light emitted from a flash discharge tube, a camera incorporating the flash device, a light source with a light amount detection sensor for detecting the amount of light emitted from the flash discharge tube, and a light source unit for the flash device.

2. Description of the Related Art Conventionally, among light emitted from a xenon discharge tube, light that is reflected by a Fresnel lens or a protective member is received by a light receiving sensor to detect the amount of light emitted from a flash device (for example, Patent Documents 1 and 2). ).
JP-A-5-127226 JP 2005-292609 A

  However, the conventional light quantity detection device provided in the flash device has a problem that it is difficult to accurately detect the light quantity because it receives external light transmitted through the Fresnel lens and the protection member together with the projection light from the xenon discharge tube.

According to a first aspect of the present invention, there is provided a flash device comprising: a rod-shaped light source having a predetermined axial direction as a longitudinal direction; a reflecting member that reflects light emitted from the light source toward a subject; and predetermined light among light emitted from the light source. And a detecting means for detecting the light amount of the light amount detecting light that is emitted in the axial direction.
According to a second aspect of the present invention, there is provided a flash device comprising: a rod-shaped light source having a predetermined axial direction as a longitudinal direction; a reflecting member that reflects light emitted from the light source toward a subject; and predetermined light among light emitted from the light source. And detecting means for detecting the light amount of the light amount detection light, which is light other than the light emitted from the peripheral surface not intersecting the axial direction.

  According to the present invention, the amount of light emitted from the light source in the axial direction of the light source is detected, so that the amount of light can be accurately detected.

-First embodiment-
A flash device according to a first embodiment of the present invention will be described with reference to the drawings. A lens barrel 2 having a photographic lens 20 is replaceably mounted on the body 10 of the camera 1 shown in FIG. The flash device 3 is detachably attached to the accessory shoe 13 of the camera 1.

  The flash device 3 includes a light source unit 30, a Fresnel lens 31, and a light emission control circuit 32. The light source unit 30 is a light source that emits subject illumination light, and is supported so as to be able to translate in the Z-axis direction of FIG. That is, the light source unit 30 is configured to be able to perform a zoom operation for changing the irradiation angle of the emitted light by a driving mechanism (not shown). A Fresnel lens 31 is provided on the front surface of the flash device 3, and light emitted from the light source unit 30 is diffused by the Fresnel lens 31 to irradiate the subject. The light emission control circuit 32 communicates various information via the control circuit 100 of the camera 1, the camera side accessory shoe 13, and the contact portion 33 on the flash device side, and based on the light emission command of the control circuit 100, the light source unit 30. Controls the light emission operation. Further, the light emission control circuit 32 compares the light emitted from the light source unit 30 with the light emission amount received from the control circuit 100 to control the light emission amount of the light source unit 30.

  The light source unit 30 will be described in detail with reference to FIG. 2A, the Z axis is the illumination light irradiation direction, the X axis is the longitudinal axis of the flash discharge tube 311 (perpendicular to the Z axis), and the Y axis is an axis orthogonal to both the Z axis and the X axis. Respectively. When the camera 1 is held in a horizontal position, the X-axis direction is the camera horizontal direction, and the Y-axis direction is the camera vertical direction.

  The light source unit 30 includes a reflective shade 300 and a light source 310. The reflection shade 300 is a reflection member for reflecting flash light emitted from the peripheral surface of the light source 310 (peripheral surface not intersecting with the X axis) toward the subject. The reflective shade 300 is configured by bending a single metal plate having a predetermined reflectance, and includes a curved portion 301 having a curved reflective surface and a pair of side reflections located on both sides of the curved portion 301 in the X-axis direction. Part 302. Each side reflecting portion 302 is configured by bending portions (four places) protruding from the curved portion 301, and the inner surface of the bent portion serves as a reflecting surface.

  The light source 310 includes a flash discharge tube 311, a diffusion plate 312, and a light amount detection sensor 313 as shown in FIG. 2B, and a light amount detection capable of detecting the amount of light emitted from the flash discharge tube 311. It is a light source with a sensor. The flash discharge tube 311 is disposed so as to penetrate the rear of the pair of side reflecting portions 302 as shown in FIG. As a result, the curved reflection surface covers the top and bottom and the back of the flash discharge tube 311, and the pair of side reflection portions 302 are arranged on the left and right with the optical axis Z of the flash discharge tube 311 interposed therebetween. An anode electrode 314 and a cathode electrode 315 are respectively provided at both ends of the flash discharge tube 311 so as to project in the X-axis direction, and are electrically connected to the light emission control circuit 32 (FIG. 1), various light emission circuits, and the like by wires not shown. It is connected to the. Further, the flash discharge tube 311 is fixed by a holding frame (not shown) so that the relative positional relationship with the reflective shade 300 does not change.

  The trigger electrode 316 is provided on one end side (cathode electrode 315 side) of a rod-shaped flash discharge tube 311 as shown in FIG. Based on the light emission instruction signal received from the control circuit 100 of the camera 1 via the accessory shoe 13, the light emission control circuit 32 instructs the trigger circuit (not shown) to apply a trigger voltage to the trigger electrode 316. The xenon gas is excited in the flash discharge tube 311 by the trigger voltage applied to the trigger electrode 316, and a light emission current of several tens of A to one hundred A or more is generated from the anode electrode 314 in the xenon tube to the cathode electrode 315 in an extremely short period. It flows to. As a result, the flash discharge tube 311 flashes.

  The diffusion plate 312 is disposed at a position away from the anode electrode 314 on the other end side where the trigger electrode 316 of the flash discharge tube 311 is not provided by a predetermined distance in the axial direction (X-axis direction) of the flash discharge tube 311. . The diffusion plate 312 is a plate-like member that diffuses light emitted in the X-axis direction from the end portion 311 a of the flash discharge tube 311. The light amount detection sensor 313 detects the amount of light emitted from the diffusion plate 312. The diffusion plate 312 is fixed to a holding frame (not shown) so that the relative positional relationship with the flash discharge tube 311 does not change. The diffusion plate 312 is provided with a pocket 312a, and a light quantity detection sensor 313 is bonded and fixed to the pocket 312a. Thus, since the relative positions of the reflective shade 300, the flash discharge tube 311, the diffusion plate 312, and the light quantity detection sensor 313 do not change, the reflective shade 300 and the light source 310 (311 to 313) are united during zoom operation. Move in the Z-axis direction.

  The light quantity detection sensor 313 converts the received light quantity of the light quantity detection light into an electrical signal and transmits it as a detection signal to the light emission control circuit 32. The light emission control circuit 32 controls the light emission amount of the flash discharge tube 311 based on the received detection signal and the light emission amount received from the control circuit 100.

Next, the operation of the flash device 3 will be described.
When a trigger voltage is applied to the trigger electrode 316 based on the light emission instruction signal received from the control circuit 100 of the camera 1, the flash discharge tube 311 flashes. When the flash discharge tube 311 emits light, the light emitted from the peripheral surface of the flash discharge tube 311 (the peripheral surface not intersecting the X axis) and traveling in the subject direction (Z direction) and the light reflected by the reflection shade 300 are reflected by the Fresnel lens 31. And the subject is irradiated with the light transmitted through the Fresnel lens 31.

  Further, direct light emitted from the flash discharge tube 311 other than the above-described peripheral surface, that is, direct light emitted from the end portion 311 a in the X-axis direction is received by the light amount detection sensor 313 through the diffusion plate 312. That is, light having a light amount corresponding to (equivalent to) light emitted from the peripheral surface of the flash discharge tube 311 is received by the light amount detection sensor 313. Then, it is converted into a detection signal by the light amount detection sensor 313 and transmitted to the light emission control circuit 32. As a result, the light emission control circuit 32 can accurately monitor the amount of light emitted from the flash discharge tube 311 and accurately control the amount of emitted light.

According to the first embodiment described above, the following operational effects can be obtained.
(1) The light amount detection sensor 313 detects the amount of light emitted from the flash discharge tube 311 in the X-axis direction of the flash discharge tube 311, that is, in the longitudinal direction of the flash discharge tube 311. did. Therefore, since the light emitted from the flash discharge tube 311 can be received without receiving external light transmitted through the Fresnel lens 31 and other members, accurate light quantity detection can be performed.

  Further, when the output light of the flash discharge tube 311 is a small amount of light, the light emission path of the emitted light from the peripheral surface of the flash discharge tube 311 is indeterminate, but the unevenness does not appear in the axially emitted light. Therefore, unlike the case where light emitted from the peripheral surface of the flash discharge tube 311 is received by the light amount detection sensor 313, the detected light amount and the photometric result of the camera 1 by the reflected light of the subject are different, and the light control accuracy is high. The situation of getting worse can be prevented.

(2) The light amount detection sensor 313 detects the amount of light emitted from the flash discharge tube 311 to the end 311 a of the flash discharge tube 311, that is, the light emitted to other than the peripheral surface of the flash discharge tube 311. I made it. Accordingly, it is possible to improve the detection accuracy of the amount of light emitted from the flash discharge tube 311 without being affected by external light transmitted through the Fresnel lens 31 and other members.

(3) The light quantity detection sensor 313 receives light emitted from the other end side where the trigger electrode 316 of the flash discharge tube 311 is not provided. Therefore, it is possible to accurately detect the amount of light emitted from the flash discharge tube 311 while minimizing the influence of noise due to the trigger voltage applied to the trigger electrode 316.

(4) A diffusion plate 312 is provided between the flash discharge tube 311 and the light amount detection sensor 313. Therefore, the light quantity detection sensor 313 can receive the direct light from the flash discharge tube 311 without exceeding its sensitivity limit, and thus can accurately detect the light quantity.

-Second Embodiment-
A flash device according to the second embodiment will be described with reference to FIG. The same components as those of the flash device 3 according to the first embodiment are denoted by the same reference numerals, and differences from the flash device 3 of the first embodiment will be mainly described.
As shown in FIG. 3, the light source 310 included in the flash device 3 according to the second embodiment is a diffusing plate that is inclined so that light emitted from the end portion 311 a of the flash discharge tube 311 enters in the X-axis direction. 318. The diffuser plate 318 is fixed to a holding frame (not shown) so that the relative position with respect to the flash discharge tube 311 does not change, and the path of the light emitted from the end 311a of the flash discharge tube 311 is, for example, in the −Y direction. Reflect and change.

  The light amount detection sensor 313 is fixed to a holding frame (not shown) so that the light receiving surface thereof faces in the + Y direction so that the light emitted from the inclined diffusion plate 318 can be received. Therefore, the light quantity detection sensor 313 receives light emitted from the end 311a of the flash discharge tube 311 in the X-axis direction, reflected by the diffusion plate 318, and directed in the -Y direction as light quantity detection light. The light quantity detection sensor 313 transmits a detection signal based on the received light quantity detection light to the light emission control circuit 32. Since both the diffuser plate 318 and the light amount detection sensor 313 are fixed to a holding frame (not shown) so that the relative positions of both do not change, the reflecting shade 300, the flash discharge tube 311, the diffuser plate 318, and the light amount during zoom operation. Both detection sensors 313 are translated in the Z-axis direction.

According to the flash device 3 according to the second embodiment described above, in addition to the functions and effects of the first embodiment, the following functions and effects can be obtained.
The diffusing plate 318 is inclined so that the light emitted from the end 311a of the flash discharge tube 311 is incident obliquely, and the light amount detection sensor 313 is provided at a position where the light amount detection light in the Y-axis direction is received. . That is, the light emitted from the end portion 311 a of the flash discharge tube 311 is deflected by the inclined diffusion plate 318 and received by the light amount detection sensor 313. Therefore, the freedom degree of the position which arrange | positions the light quantity detection sensor 313 can be improved.

-Third embodiment-
With reference to FIG. 4, a flash device according to a third embodiment will be described. The same components as those of the flash device 3 according to the first embodiment are denoted by the same reference numerals, and differences from the flash device 3 of the first embodiment will be mainly described.
As shown in FIG. 4, the light source 310 of the third embodiment is configured to guide light emitted from the diffusion plate 312 to the light amount detection sensor 313 via a light guide member 319 such as an optical fiber cable. .

  Light emitted from the end 311 a of the flash discharge tube 311 and incident on the diffusion plate 312 becomes diffused light at the diffusion plate 312. The light emitted from the diffusion plate 312 enters the light guide member 319 from one end 319a of the light guide member 319, passes through the light guide member 319, and is emitted from the other end 319b. The light quantity detection sensor 313 receives the light emitted from the light guide member 319 as light quantity detection light, converts it into an electrical signal, and outputs it to the light emission control circuit 32 as a detection signal.

According to the flash device 3 according to the third embodiment described above, in addition to the functions and effects of the first embodiment, the following functions and effects can be obtained.
A light guide member 319 for guiding the light emitted in the longitudinal direction of the flash discharge tube 311 to the light amount detection sensor 313 is provided. Therefore, even if the light amount detection sensor 313 is arranged at a position away from the flash discharge tube 311 so as not to be affected by noise caused by the light emission of the flash discharge tube 311, the direct light of the flash discharge tube 311 is emitted as a light amount. Since the light can be guided to the detection sensor 313, accurate light quantity detection is possible.

The embodiment described above can be modified as follows.
(1) Instead of performing the zoom operation by moving the light source unit 30 in the Z-axis direction, the light source 310 may move in the Z-axis direction and perform the zoom operation. In this case, as shown in the cross-sectional view of the plane including the X axis in FIG. 5, the flash discharge tube 311, the diffusion plate 312, and the light amount detection sensor 313 are attached to the light-transmissive holding frame 317 so that the relative positions thereof do not change. The light source 310 is formed by being fixed. The light source 310 may be moved by a zoom mechanism (not shown) along the opening 303 provided in the pair of side reflecting portions 302 of the reflecting shade 300 and having a longitudinal direction coinciding with the Z-axis direction. The light source 310 may include the diffusion plate 318 described in the second embodiment and the light guide member 319 described in the third embodiment.

(2) In the third embodiment, the light guide member 319 guides the light diffused by the diffusion plate 312 to the light amount detection sensor 313, but the light emitted from the flash discharge tube 311 is guided by the light guide member 319. May be guided to the diffusion plate 312 and detected by the light amount detection sensor 313.

(3) The present invention is not limited to an external flash device that can be attached to and detached from the camera 1, but can also be applied to a flash device built in the camera.
(4) In each of the above embodiments, the end 311a of the flash discharge tube 311 may be formed as a diffusion surface. In this way, the diffusion plate 312 provided in the first and third embodiments can be omitted. In the second embodiment, a simple mirror can be arranged instead of the diffusion plate 318.

  In addition, the present invention is not limited to the above-described embodiment as long as the characteristics of the present invention are not impaired, and other forms conceivable within the scope of the technical idea of the present invention are also within the scope of the present invention. included.

It is a figure explaining the principal part structure of the flash device and camera by embodiment of this invention. It is a figure explaining the external appearance of the light source unit of the flash device in 1st Embodiment, (a) is a perspective view of a light source unit, (b) is a top view of a light source. It is a perspective view explaining the external appearance of the light source unit of the flash device in 2nd Embodiment. It is a perspective view explaining the external appearance of the light source unit of the flash device in 3rd Embodiment. It is sectional drawing explaining the light source unit in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Flash apparatus 30 Light source unit 300 Reflection shader 310 Light source 311 Flash discharge tube 311a End part 312 Diffusing plate 313 Light quantity detection sensor 316 Trigger electrode 319 Light guide member

Claims (14)

A rod-shaped light source having a predetermined axial direction as a longitudinal direction;
A reflecting member that reflects light emitted from the light source toward the subject;
A flash device comprising: a detecting unit that detects a light amount of a light amount detecting light that is a light emitted in the predetermined axis direction out of the light emitted from the light source. A rod-shaped light source having a predetermined axial direction as a longitudinal direction;
A reflecting member that reflects light emitted from the light source toward the subject;
Detecting means for detecting a light amount of a light amount detecting light that is light other than light emitted from a peripheral surface that does not intersect the predetermined axis direction among the light emitted from the light source. Flash device. The flash device according to claim 1 or 2,
The light source is a discharge tube, and has a light emitting trigger electrode on one end side thereof,
The flash device according to claim 1, wherein the detecting means receives light emitted from the other end of the light source. The flash device according to any one of claims 1 to 3,
A flash device, wherein a diffusion plate is provided between the light source and the detection unit, and the detection unit receives light diffused by the diffusion plate. The flash device according to claim 4,
2. A flash apparatus according to claim 1, further comprising deflecting means for deflecting a path of the light quantity detecting light, wherein the detecting means is provided at a position for receiving the light quantity detecting light whose path is deflected by the deflecting means. The flash device according to claim 5,
The flashing device, wherein the deflecting means is also used as the diffusing means. The flash device according to any one of claims 1 to 6,
A flash device further comprising a light guide member for guiding the light amount detection light to the detection means.   A camera characterized in that the flash device according to any one of claims 1 to 7 is built-in or detachable. A rod-shaped light source having a predetermined axial direction as a longitudinal direction;
A light source with a light quantity detection sensor, comprising: a detecting means for detecting a light quantity of a light quantity detection light that is a light emitted in the predetermined axis direction out of the light emitted from the light source. The light source with a light quantity detection sensor according to claim 9,
The light source is a discharge tube, and has a light emitting trigger electrode on one end side thereof,
The light source with a light amount detection sensor, wherein the detecting means receives light emitted from the other end side of the light source. The light source with a light amount detection sensor according to claim 10,
A light source with a light amount detection sensor, wherein a diffusion plate is provided between the light source and the detection unit, and the detection unit receives light diffused by the diffusion plate. The light source with a light amount detection sensor according to claim 11,
With a light quantity detection sensor, further comprising a deflecting means for deflecting a path of the light quantity detecting light, wherein the detecting means is provided at a position for receiving the light quantity detecting light whose path is deflected by the deflecting means. light source. The light source with a light amount detection sensor according to any one of claims 9 to 12,
A light source with a light amount detection sensor, further comprising a light guide member for guiding the light amount detection light to the detection means. A light source with a light amount detection sensor according to any one of claims 9 to 13,
A light source unit for a flash device comprising at least a reflecting member that reflects light emitted from the light source toward a subject.

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