JPH06242498A - Flash light emitting device - Google Patents

Abstract

PURPOSE:To change the irradiating direction and luminous intensity distribution angle of a light emitting part and to attain the arrangement in an economized space with a simple mechanism by providing a diffraction grid freely moved to positions for covering the front of a flash light emitting tube and retracting therefrom. CONSTITUTION:A built-in stroboscope 5 is composed of the light emitting part 5a composed of a discharge tube 12 and a reflector 13 and a macro adapter 14. The macro adapter 14 is obtained in such a manner that an optical diffraction element is formed on the surface of a plate made of transparent plastic and has a shape and size to cover the whole of an opening part on the front surface of the reflector 13. In macro photographing that a subject distance is extremely short, light is made incident on the macro adapter 14 and diffracted thereon and the irradiating direction is inclined toward the optical axis 0 of a lens (front downward), to execute irradiation. On the other hand, in normal photographing, the micro adapter 14 is moved to the lowermost position and retracted from the front surface of the light emitting part 5a. Therefore, the light emitted from the light emitting part 5a directly transmits a cover glass without the macro adapter 14 and is projected forward in parallel with the optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash light emitting device, and more particularly to a flash light emitting device capable of varying the irradiation direction and the light distribution angle of flash light emission in accordance with the focal length of a photographing lens.

[0002]

2. Description of the Related Art Conventionally, according to the focal length of a photographing lens,
Various flash light emitting devices have been proposed for changing flash light emission to an appropriate irradiation direction and light distribution angle. For example, Japanese Patent Laid-Open No. 3-6
In the strobe device disclosed in Japanese Patent No. 4740, a strobe light emitting portion is tiltably provided on a camera body so that a stroboscopic light irradiation direction approaches a light axis of a photographing lens during macro photography. The macro operation button or the lever connected to the lens barrel that operates by moving the lens barrel to the macro shooting position changes the flash light irradiation direction to the optical axis direction during macro shooting. It is to tilt.

Further, as disclosed in Japanese Patent Application Laid-Open No. 2-273729, an optical lens in which a light emitting portion of a flash light emitting device is arranged on the front surface in accordance with a change in focal length due to a zooming operation of a photographing lens. On the other hand, by moving in parallel with the optical axis direction of the taking lens and changing the interval with the optical lens, the light distribution angle can be changed and the irradiation direction of the light emitting unit can also respond to the change of the focal length. As the distance from the telephoto side to the wide-angle side is changed, there is also a means of controlling the irradiation direction of the light emitting unit by inclining in the optical axis direction from a state substantially parallel to the optical axis direction of the photographing lens.

[0004]

However, the strobe device disclosed in Japanese Patent Laid-Open No. 3-64740 requires a support member for tilting the light emitting portion of the strobe, and the light emission is also required. The space on the locus in which the part tilts becomes a dead space in which no other member can exist, and since a thick lead wire is connected to the discharge tube of the light emitting part, the lead wire moves the light emitting part. However, there is a drawback in that it causes a large driving load.

Further, in the one disclosed in Japanese Patent Application Laid-Open No. 2-273729, since the light emitting portion is moved in accordance with the zoom range, a large space is required, which leads to an increase in size of the device and the above-mentioned light emission. Since the driving load of the parts also becomes large, there is a problem that the driving unit is complicated and leads to an increase in size.

The object of the present invention is to solve the above-mentioned problems, and it is possible to change the irradiation direction and the light distribution angle of the light emitting portion of the flash light emitting device, and to save space with a simple mechanism. It is to provide a flash light emitting device that can be arranged.

[0007]

The flash light emitting device of the present invention is an irradiation range comprising a flash light emitting tube and a diffraction grating which is movable between a position covering the front of the flash light emitting tube and a position retracted therefrom. And a changing unit.

[0008]

The light emitted from the flash arc tube is irradiated by the irradiation range changing means by changing the irradiation direction and the light distribution angle.

[0009]

The present invention will be described below with reference to the illustrated embodiments. 1 to 5 show a first embodiment of the present invention. This embodiment is an application of the present invention to a single-lens reflex camera with a built-in flash. It is bent in the direction of the optical axis to prevent uneven irradiation due to the deviation between the optical axis of the taking lens and the irradiation direction of the strobe light emitting section.

As shown in FIG. 1, in the camera of the first embodiment, the film 1 is stretched in the vicinity of the lower rear surface portion inside the camera body 58, as in a normal single-lens reflex camera. A movable reflection mirror 2 is obliquely provided in front of 1 at an angle of 45 degrees, and is rotatably supported so as to be retracted upward from the optical path of the photographing by a release operation at the time of photographing. Then, in front of the reflection mirror 2,
A taking lens barrel 3 held by a lens barrel holding plate (not shown) is provided.

A focusing screen 17 is arranged above the reflection mirror 2 and the reflection mirror 2 is obliquely arranged. When observing a camera, a subject that has passed through the optical system of the lens barrel 3 is observed. The image is the reflection mirror 2
The light is reflected upward by and is imaged on the focusing screen 17. The focusing screen 17
A pentaprism 4 is provided above the above, and an eyepiece lens 55 is provided behind the pentaprism 4. Then, the subject image formed on the focusing screen 17 is confirmed by the eyepiece lens 55.
Here, when the release operation at the time of shooting is performed, the reflection mirror 2 retracts upward, and the subject image that has passed through the shooting optical system is exposed on the film 1.

Further, in the vicinity of the front upper diagonal portion of the pentaprism 4, the built-in strobe 5 of the present invention is located at a position where the front portion of the strobe 5 and the rear portion of the lens barrel 3 vertically overlap. Are arranged as follows. The light emitting portion 5a of the strobe 5 (see FIG. 2) is arranged so that the irradiation direction of the strobe 5 is the optical axis of the photographing lens in the lens barrel 3 so that the irradiation range always coincides with the photographing range in a normal photographing state. It is fixed so that it is oriented substantially parallel to 0. A transparent cover glass 7 is fitted to a window frame opened at the front upper part of the exterior cover 6 of the camera at a position in front of the strobe 5 and facing the light emitting portion 5a. Then, the discharge tube 12 provided inside the light emitting section 5a (see FIG. 2).
The flash light is transmitted through the cover glass 7 and emitted toward the front.

As shown in FIG. 2, a focusing ring 8 for focusing is rotatably arranged on the rear half of the lens barrel 3 with respect to the lens barrel 3 and rotates. Due to
The focusing lens held inside the lens barrel 3 is driven to focus. A drive gear portion 8a is provided on the outer periphery of the front portion of the focus ring 8, and the drive gear portion 8a is driven by a pinion gear 10a fixed to the output shaft of the lens drive motor 10 via a reduction gear 9. The force is transmitted and the focus ring 8 is rotationally driven. The lens drive motor 10 rotates in response to an output from an arithmetic control circuit (not shown) based on AF distance measurement information obtained from the AF sensor 11 shown in FIG. 1, and this rotation is driven by the drive gear of the focus ring 8. It is transmitted to the portion 8a, and the lens is driven to focus.

As shown in FIG. 2, the built-in strobe 5 comprises a light emitting portion 5a including a discharge tube 12 and a reflector 13, and a macro adapter 14. The discharge tube 12 emits a discharge, and is horizontally arranged in the vicinity of the central portion inside the reflector 13. The reflector 13 forms an exterior part of the strobe 5, and reflects the light emitted from the discharge tube 12 toward the front. Both sides of the reflective umbrella 1
3a and 13b are provided with elongated guide holes 13c and 13d in the vertical direction near the front edge thereof.

The macro adapter 14 is formed by forming an optical diffractive element on the surface of a flat plate made of transparent plastic, and has a shape and size that covers the entire front opening of the reflector 13. At the upper portions of both side surfaces of the macro adapter 14, engaging pins 14a, 14b protruding horizontally are formed.
Is provided. The engagement pins 14a and 14b are fitted in the guide holes 13c and 13d, respectively, and the macro adapter 14 can move up and down along the guide holes 13c and 13d. Further, the macro adapter 14 is formed with a hook portion 14c protruding rearward at a lower portion on one side of a rear surface thereof, and a spring spring 15 has one end portion locked to the hook portion 14c, The other end is fixed to an immovable part such as the camera body 58 or the exterior cover 6, and the macro adapter 14 is constantly urged so as to be pulled down by the extension elasticity of the spring spring 15.

On the other hand, on a part of the outer peripheral surface of the rear part of the focus ring 8, an engaging projection 8b is provided so as to extend along the outer circumference, and the projection 8b engages with the connecting lever 16. The connecting lever 16 has a substantially L shape, and is provided between the lens barrel 3 and the strobe 5. The lever 1
6, a support pin 16a is fixed to one arm near the focus ring 8, and the support pin 16a is attached to the exterior cover 6
The pin 16a is fitted in and is rotatably held around the pin 16a. The one end of the connecting lever 16 has a focus ring 8
Of the macro adapter 14, and the other arm end of the macro adapter 14 is in contact with the adapter pin 14d which projects forward from the lower edge of the front surface of the macro adapter 14.

Next, the switching operation of the irradiation direction of the built-in strobe of the first embodiment constructed as described above will be explained. When performing macro photography with a very short subject distance, the focus ring 8 is moved to the arrow r shown in FIG.
Rotate in the direction of. Then, since the protrusion 8b presses one arm end of the connecting lever 16, the lever 16 swings around the support pin 16a, and the other arm end of the lever 16 presses the adapter pin 14d upward. Then, the macro adapter 14 is arranged at a position covering the front surface of the light emitting portion 5a of the strobe 5. Therefore, when the light emitting portion 5a of the strobe 5 emits light in this state, this light enters the macro adapter 14 and is diffracted there, and the irradiation direction is inclined toward the direction of the lens optical axis 0 (lower front). To be done.

On the other hand, during normal shooting, the focusing ring 8 rotates in the direction opposite to the arrow r (see FIG. 2) during the focusing operation, and the projection 8b releases the pressing of the connecting lever 16 on one arm end. To do. Then, since the other arm end of the lever 16 releases the upward pressing of the adapter pin 14d, the macro adapter 14 is guided by the guide hole 13c of the reflector 13.
It moves to the lowest position along 13d and retracts from the front surface of the light emitting section 5a. Therefore, the light emitted from the light emitting section 5a directly passes through the cover glass 7 without passing through the macro adapter 14 and is emitted forward in parallel with the optical axis.

The optical diffractive element formed on the macro adapter 14 can macroscopically have a power for bending light on a plane, and further has an exit angle j with respect to an incident angle i viewed macroscopically. Then, the following formula is established.

Na.SIN (i) .noteq.Nb.SIN (j) (in the case of refraction) where Na is the refractive index on the incident side and Nb is the refractive index on the exit side.

3 and 4 are enlarged views of the main part of the diffractive element used in this embodiment, and FIG. 3 is a blazed diffractive element 14
A and FIG. 4 are referred to as a form modulation type diffraction element 14B. Here, as shown in FIGS. 3 and 4, when the pitch of the diffractive optical element is d and the step of the same pitch is h, the incident angle is i, the exit angle is j, and the light wavelength λ of the flash light is the m-th order diffracted light. Then, the following equation holds.

SIN (i) -SIN (j) = mλ / d Further, it is desirable that the pitch step h conforms to the following equation.

H = mλ / (nb-na) where na is the refractive index of the medium on the incident side and nb is the refractive index of the medium on the exit side.

As described above, in the first embodiment, by utilizing the action of the optical diffraction element, as shown in FIG. 5, the light emitted directly from the discharge tube or the light reflected by the reflector is incident on the incident angle. On the other hand, when the light is transmitted through the macro adapter 14, the emission angle can be changed with respect to the incident angle and the light beam can be bent to irradiate the emitted light in the optical axis direction 0.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the present invention has a built-in strobe of a single-lens reflex camera, and a bounce adapter having an optical diffraction element is disposed in front of the strobe's light emitting portion, so that the strobe emits light directly toward a subject. It is designed to allow bounce shooting with a single built-in flash, separately for flashing toward the ceiling.

The strobe built-in type camera of the second embodiment is different from that of the first embodiment only in the adapter of the optical diffraction grating arranged in front of the built-in strobe and the switching mechanism of the same adapter, and other configurations. Is almost the same as that of the first embodiment. Therefore, only the differences will be explained,
The same components are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 6, a bounce adapter 14C is arranged on the front surface of the built-in strobe 5A so as to be movable downward as in the case of the first embodiment.
An engaging pin 14e projects forward from a lower edge portion of the front surface of C on one side. Further, a lateral T-shaped set member 18 is disposed on one side in front of the strobe 5A, and a central protruding arm 18 of the set member 18 is provided.
The fork 18b at the tip of a is fitted to the engaging pin 14e. Click recesses 18c and 18d are provided in the vertical direction at a side edge of the setting member 18 opposite to the protruding arm 18a, and the click spring 1 is provided in one of the recesses.
9 is engaged to move the setting member 18 to the lowered normal position and the raised bounce position. The bounce adapter 14C retracts downward from the front surface of the strobe 5A at the normal position, moves so as to cover the front surface of the strobe 5A at the bounce position, and is held at the moving position by the click stop mechanism. . Similar to the first embodiment, the bounce adapter 14C has an optical diffraction element formed on a plastic flat plate, and the pitch h shown in FIGS. Make the intensity distribution of only the 1st order diffracted light that refracts at the minimum angle with
As shown in FIG. 7, the 0th-order diffracted light is a straight-ahead light and the 1st-order diffracted light is a bounce light toward the ceiling.

As described above, in the second embodiment, by switching the setting member 8 and retracting the bounce adapter 14C from the front surface of the strobe or by disposing it on the front surface,
You can shoot with normal flash and bounce flash.

FIGS. 8 to 10 show a third embodiment of the present invention. In this embodiment, several optical diffractive elements having different pitches are switched and arranged on the front surface of the light emitting portion of the external strobe. In this way, several types of light emission with different light distribution angles and irradiation directions are emitted.

As shown in FIG. 8, in the flash light emitting device of the third embodiment, the exterior housing is composed of a front cover 20 and a rear cover 21, and the entire strobe has its upper part slightly forward. It has an inclined shape. The front cover 2
In No. 0, the upper part of the front surface projects forward, and a light emitting opening is formed in the front surface, and a light emitting window 22 made of a transparent material is attached to this opening. Inside the strobe, behind the light emitting window 22, a light emitting portion 23 is arranged with a light distribution angle changing sheet 24 arranged on the front surface, and further, a charge for flashing is accumulated behind the light emitting portion 23. A main condenser 25 is provided. The main capacitor 2
A battery chamber 26 is provided in the lower part of the unit 5. The battery chamber 26 is arranged so as to be sandwiched by the front cover 20 and the rear cover 21.
The batteries 6 are formed so as to be held in a row in the horizontal direction in the vertical direction.

A flash circuit board 29, on which components such as a transformer 27 and a thyristor 28 are mounted, is arranged in the front part of the battery chamber 26, for controlling light emission in the rear part of the battery chamber 26. The control circuit board 30 of FIG. A liquid crystal display plate 31 for displaying various information such as a flash emission mode is attached to the control circuit board 30 so as to face rearward, and is attached to the rear cover 21 at a position facing the liquid crystal display plate 31. The content displayed on the liquid crystal display panel 31 can be confirmed through the display window 32 made of a transparent material. Further, the mode setting and the like are performed by operating the operation button 33 arranged on the lower portion of the display window 32.

A holding base 34 is formed on the lower part of the strobe, and the strobe main bodies arranged on the front cover 20 and the rear cover 21 are fixed to the upper part of the holding base 34, and A foot 35 for connecting to a flash-attaching hot shoe of the camera is fixedly provided on the lower portion thereof. The foot 35 has a plurality of electric contacts 36, 37, 38 for inputting and outputting various signals including a light emission trigger signal from a camera so that the foot 35 can advance and retreat vertically with respect to the bottom surface of the foot 35. It is urged by a spring (not shown).

Next, the light emitting portion of the strobe of the third embodiment will be described. As shown in FIG. 9, the upper portion of the front cover 20 (see FIG. 8) is provided with the reflector 40 as in the first embodiment, and the discharge tube 39 is horizontally held inside. Has been done. The reflector 40 has an opening for emitting light emitted in front of the strobe, and as described above, the irradiation angle changing sheet 24 is provided in the front of the reflector 40, and further in front of it. A light emitting window 22 (see FIG. 8) fixed to the front cover 20 is arranged. The irradiation angle changing sheet 24 has an optical diffractive element formed in each region, and is formed, for example, on a transparent and flexible resin substrate so that it can be stored in a roll shape and can be developed in a flat shape. An optical diffractive element is formed on a thermally laminated photopolymer.

FIG. 10 is a development view of the irradiation angle changing sheet 24. Several areas 24a, 24b, having different pitches d or pitch steps h of the optical diffraction grating as shown in FIG. 3 and FIG. 24c, 24d, etc. (optical diffractive element is not shown) are formed separately, and when the respective regions are arranged on the front surface of the reflector 40,
It has a size and shape that completely covers the opening of the reflector 40.

Returning to FIG. 9, the irradiation angle changing sheet 24 is provided.
A lower guide roller 41 and an upper guide roller 42 are horizontally arranged at the upper part and the lower part of the reflecting umbrella 40 at the rear of the above, and the guide roller 41, 42 determines the use area of the irradiation angle changing sheet 24. It is developed in a plane shape on the front surface of the reflector 40. Then, a lower take-up roller 43 and an upper take-up roller 44 are provided at the rear portions of the lower guide roller 41 and the upper guide roller 42, respectively.
And the unused area of the irradiation angle changing sheet 24 is wound up by the lower winding roller 43 and the upper winding roller 44 and stored in the lower rear portion and the upper rear portion of the reflecting umbrella. To be done.

The take-up rollers 43, 44 have a lower connecting gear 45 and an upper connecting gear 46 fixed to their respective shafts. The lower connecting gear 45 is directly connected to the upper connecting gear 46 and the idle connecting gear 46 is connected to the idle gear 53. Via 54, it is connected to a planetary gear mechanism that is switched by a switching motor 47. A region to be used on the irradiation angle changing sheet 24 is selected and switched according to the rotation direction and the rotation amount of the switching motor 47.

In the planetary gear mechanism, the sun gear 4 is attached to the pinion gear 48 fixed to the rotary shaft of the switching motor 47.
In the sun gear 49, a swing lever 50 having two arms is pivotally supported on the sun gear 49 with the swing center axis at the intersection of both arms as the rotation center axis. A lower planet gear 51 and an upper planet gear 52 that mesh with the sun gear 49 are pivotally supported at both ends of each arm of the swing lever 50. The lower planetary gear 51 meshes with the lower connecting gear 45, and the upper planetary gear 5 also
Reference numeral 2 meshes with the idle gear 53, the idle gear 53 meshes with the idle gear 54, and the idle gear 54 meshes with the connecting gear 46.

Further, in order to detect the rotation amount of the switching motor 47, a rotary wheel 56 having radial slits is fixed coaxially with the idle gear 54, and in order to detect the presence or absence of the slits, A photo interrupter 57 is arranged in the gap so as to sandwich the rotary wheel 56.

Next, switching control by the switching motor of the use area of the irradiation angle changing sheet shown in FIG. 9 will be described. When the pinion gear 48 of the switching motor 47 rotates in the direction of arrow r1, the sun gear 49 rotates in the direction of arrow r2, and the rocking lever 50 also rocks in the direction of arrow r2. The planet gear 51 meshes with the lower connecting gear 45 to rotate the lower connecting gear 45 in the direction of arrow r3. Then, the irradiation angle changing sheet 24 is
The irradiation angle changing sheet 24 is wound around the lower winding roller 43 and moved in the direction of the arrow s to switch the irradiation angle changing sheet 24 to the use area wound around the upper winding roller 44.

Next, when the switching motor 47 rotates in the direction opposite to the arrow r1, the sun gear 49 moves the arrow r2.
And the swing lever 50 also moves in the same direction as the arrow r.
The upper planetary gear 52 meshes with the idle gear 53 by swinging in the direction opposite to 2, and the upper connecting gear 46 rotates in the direction of arrow r4 via the idle gear 54.
Then, the irradiation angle changing sheet 24 is wound around the upper winding roller 44 and moves in the direction opposite to the arrow s, and the irradiation angle changing sheet 24 is moved to the lower winding roller 4.
Switch to the use area wound in 3.

In any of the above cases, the amount of movement of the irradiation angle changing sheet 24 is detected by the rotation of the rotary wheel 56 as a pulse signal indicating the presence or absence of a slit, and the switching motor 47 is operated.
Is driven by a predetermined pulse amount, and the irradiation angle changing sheet 2
It is controlled so as to switch 4. The control is performed by the control circuit on the control circuit board 30 shown in FIG. 8, and the signal input for switching is the operation of the operation button 33 or the control signal from the camera side via the contacts 36, 37, 38. Done by.

As described above, in the third embodiment, the respective regions of various optical diffractive elements are switched and arranged on the front surface of the reflector 40 to describe the first and second embodiments. With the same effect as that of the optical diffraction element, a wide variety of emission angles and irradiation directions can be changed.

[0043]

As described above, according to the present invention, the Fresnel lens for rotating or moving the entire light emitting portion or for converting the light emitting portion is arranged on the front surface of the light emitting portion as in the conventional case, and a predetermined amount of light is emitted. Compared with the method of controlling movement, various irradiation directions can be converted only by disposing the diffractive optical element formed on one substrate on the front surface of the light emitting unit. The effect can be obtained. Also,
Since it can be configured with a small number of parts, there is also an effect of weight reduction. Further, by forming a plurality of diffraction grating patterns with different pitches or step differences on one substrate, it is possible to realize both with a single device in the conventional technology, such as the bounce function and the zoom function. It is possible to easily combine difficult functions.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a single-lens reflex camera incorporating a flash light emitting device showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of a single-lens reflex camera incorporating the flash light emitting device of the first embodiment.

FIG. 3 is an enlarged cross-sectional view of a main part of a macro adapter forming the blazed optical diffraction element in the first embodiment.

FIG. 4 is an enlarged cross-sectional view of a main part of a macro adapter that forms the form modulation type optical diffraction element in the first embodiment.

FIG. 5 is a longitudinal sectional view of a main part showing a light emission irradiation direction of the built-in flash of the first embodiment.

FIG. 6 is a perspective view of a main part of a single-lens reflex camera incorporating a flash light emitting device showing a second embodiment of the present invention.

FIG. 7 is a longitudinal cross-sectional view of a main part showing a light emission irradiation direction of the built-in flash of the second embodiment.

FIG. 8 is a vertical cross-sectional view of an external strobe showing a third embodiment of the present invention.

FIG. 9 is a perspective view of a main part of an external strobe according to the third embodiment.

FIG. 10 is a plan view of an irradiation angle changing sheet having respective regions in which diffractive optical elements are formed in the third embodiment.

[Explanation of symbols]

12, 39 ... Discharge tube (flash arc tube) 14 ... Macro adapter (irradiation range changing means) 17 ... Bounce adapter (irradiation range changing means) 24 ... Irradiation range changing means)

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[Procedure amendment]

[Submission date] April 9, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

On the other hand, during normal shooting, the focusing ring 8 rotates in the direction opposite to the arrow r (see FIG. 2) during the focusing operation, and the projection 8b releases the pressing of the connecting lever 16 on one arm end. To do. Then, the other arm end of the lever 16 releases the upward pressing of the adapter pin 14d , and
The extension elasticity of the ring spring 15 causes the macro adapter 14 to move to the lowermost position along the guide holes 13c and 13d of the reflector 13 and retract from the front surface of the light emitting unit 5a. Therefore, the light emitted from the light emitting portion 5a directly passes through the cover glass 7 without passing through the macro adapter 14 and is emitted forward in parallel with the optical axis.

Claims (1)

[Claims] 1. A flash luminous tube, and an irradiation range changing means composed of a diffraction grating, which is movable between a position covering the front of the flash luminous tube and a position retracted from the flash luminous tube. Flash light emitting device.