JP3760043B2 - Strobe discharge tube reflector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a strobe discharge tube reflector, and more particularly to a strobe discharge tube reflector used in a lens-fitted photo film unit or a strobe device of a small camera.
[0002]
[Prior art]
A film unit with a lens in which an unexposed photographic film is loaded in advance on a unit body incorporating a simple photographing mechanism is manufactured and sold by the present applicant. There are various types of lens-equipped film units, and some have built-in strobe devices that allow shooting indoors or at night.
[0003]
As shown in FIG. 7, the strobe device 2 incorporated in the lens-fitted photo film unit has a simplified structure for manufacturing the lens-fitted photo film unit at low cost, and forms a strobe light emitting unit 3 and a strobe circuit. The electric parts and the like are attached to the printed circuit board 4 to form a unit.
[0004]
The strobe light emitting unit 3 includes a strobe discharge tube 5, a reflector 6 that reflects light from the strobe discharge tube 5 forward, a reflector case 7 that houses and holds these, and a transparent protector that is attached to the reflector case 7. 8. The strobe discharge tube 5 emits light when the electric charge charged in the main capacitor 9 is discharged therein. The reflector 6 is formed by bending an aluminum plate, and has an arcuate receiving surface 6 a for receiving the strobe discharge tube 5. A trigger terminal 10 is disposed in the reflector case 7, and the trigger terminal 10 is in contact with the outer surface of the reflector 6. When the shutter is pressed during photographing, the trigger voltage generated by the trigger transformer 11 in synchronization with the shutter release operation is applied to the strobe discharge tube 5 via the trigger terminal 10 and the reflector 6, and the strobe discharge tube 5 emits light.
[0005]
The vertical cross-sectional shape of the reflector 6 is almost elliptical, and a moderate light distribution is obtained by this elliptical curved reflecting surface. In addition to using an elliptical arc-shaped curved reflecting surface, the curved reflecting surface is also formed by a function curve such as a hyperbola or a parabola.
[0006]
[Problems to be solved by the invention]
However, in the reflector using the curved reflecting surface having an elliptical cross section, it is difficult to control the light beam into the irradiation surface, and the light collection efficiency (light beam reaching into the photographing screen / total light beam from the strobe discharge tube) exceeds a certain level. It was difficult to improve. In the case of a reflector using a function curve, it is possible to increase the light collection efficiency by giving a lens effect to a transparent protector that covers the front surface of the reflector. However, in this case, a certain length of depth is required, and the entire light emitting unit is enlarged. Further, if the protector is made of a Fresnel lens, the molding suitability is deteriorated and the cost is increased. Such a problem is not limited to a lens-fitted photo film unit, but also occurs in a strobe device of a small camera.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a reflector for a strobe discharge tube that can improve the light collection efficiency with a simple structure and to solve the above problems.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the reflector for a strobe discharge tube of the present invention has a discharge tube receiving portion for applying a trigger voltage to the strobe discharge tube, and a peripheral surface reflection portion continuous to the discharge tube receiving portion, In a reflector for a strobe discharge tube in which light emitted from the center of the strobe discharge tube by the peripheral reflection portion illuminates an effective irradiation area that is a photographing screen range of the camera, a vertical cross-sectional shape of the peripheral reflection portion is an arc or an elliptical arc. , together constituting sequentially by a linear, connected to have a common tangent at a joint of the arc and elliptical arc, and to the straight line and the tangent of the elliptical arc, the by arcuate curved reflective surface having a circular arc cross sectional shape irradiating the range from the upper end of the effective irradiation area to the lower end of the central area in the vertical direction of the effective radiation area, elliptical arc having a longitudinal sectional shape of the elliptic arc The lower end vicinity is irradiated with the central area, is irradiated with a range of the flat reflective surface having a vertical cross-sectional shape of the straight line from the vicinity of the lower end portion of the central area to the central portion of said central area by the curved reflecting surface, the circle The arc-shaped curved reflecting surface, the elliptical arc-shaped curved reflecting surface, and the flat reflecting surface are arranged at a line symmetrical position with respect to a horizontal line passing through the center of the strobe discharge tube.
[0009]
In addition, it is preferable that the discharge tube receiving portion is formed with a diameter equal to or greater than the strobe discharge tube diameter, and the formation angle of the discharge tube receiving portion is within a range of 30 to 60 degrees with respect to the line symmetry reference line. Further, it is preferable that the vertical length of the central area is half of the vertical length of the effective irradiation area, and the center of the central area is aligned with the center of the effective irradiation area. The discharge tube receiving portion is preferably formed longer than the arc length of the strobe discharge tube.
[0013]
[Action]
In the case of a strobe device reflector that prioritizes miniaturization, the transparent protector that covers the reflector does not need a lens effect, and it has been found that the light collecting efficiency is better when the direction of light irradiation is controlled by the reflector alone. In order to increase the light collection efficiency, various experiments were performed by changing the shape and location of the reflective surface of the peripheral reflection part covering the peripheral surface of the strobe discharge tube and the side reflection part covering both ends of the strobe discharge tube. And discussed. As a result, the arc, elliptical arc, and straight line are continuous so that they are continuous with the discharge tube receiving surface, rather than the vertical cross-sectional shape of the curved surface that is continuous with the discharge tube receiving surface of the peripheral reflecting portion is simply an elliptical arc or arc. It was found that the composite reflecting surface formed in this way is more advantageous in terms of light collection efficiency and light distribution control. That is, the condensing efficiency with respect to the effective irradiation area serving as the imaging screen is improved by configuring the peripheral surface reflection portion by continuing the arc, elliptical arc, and straight line so as to be continuous with the discharge tube receiving surface. Further, it is possible to eliminate a light distribution depression (partial decrease in the amount of light) in the vicinity of the center of the effective irradiation area, which has occurred in a conventional reflector having an elliptical cross section.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the reflector 15 of the present invention is formed by press-molding a thin metal plate and is disposed so as to cover the peripheral surface of the strobe discharge tube 16 (see FIGS. 2 and 4). The peripheral surface reflection part 17 and the side surface reflection part 18 arrange | positioned so that the both ends of the strobe discharge tube 16 may be covered are comprised.
[0015]
FIG. 2 is an enlarged cross-sectional view showing the longitudinal cross-sectional shape of the peripheral reflection portion 17, and only the upper half cross-sectional shape is shown in order to avoid complication of the drawing. Note that the lower half of the peripheral reflection portion 17 is formed symmetrically with the horizontal line passing through the center of the strobe discharge tube 16 as a reference line S1, and has the same cross-sectional shape as the upper half.
[0016]
The peripheral surface reflecting portion 17 includes a discharge tube receiving portion 20 having an arcuate receiving surface 20a for receiving the strobe discharge tube 16, an arcuate curved portion 21 having an arcuate curved reflecting surface 21a continuous to the receiving surface 20a, An elliptical arc-shaped curved portion 22 having an elliptical arc-shaped curved reflecting surface 22a and a flat portion 23 having a flat reflecting surface 23a are successively arranged.
[0017]
The strobe discharge tube receiving surface 20a is a curved surface having a cross-sectional arc EA having a radius of 1.25 mm with respect to the strobe discharge tube 16 having an outer diameter (diameter) of 2.5 mm. The curved surface forming angle θ1 is in a range of 30 ° ≦ θ1 ≦ 60 ° with respect to the reference line S1 passing through the center of the strobe discharge tube 16. By setting the formation angle θ1 to 30 ° or more, the trigger voltage can be reliably applied from the receiving surface 20a. Further, by setting the formation angle θ1 to 60 ° or less, the amount of light re-incident on the discharge tube 16 by the discharge tube receiving portion 20 can be reduced.
[0018]
The arcuate curved reflecting surface 21a has a vertical cross section of an arc AB, and the radius of the arcuate curved reflecting surface 21a is about 1.6 to 2.4 mm with respect to the outer diameter of the discharge tube of 2.5 mm. Then, the light beam emitted from the center P1 of the discharge tube is reflected by the arcuate curved reflecting surface 21a, and the reflected light beam is centered from a point A ′ near the upper end of the effective irradiation area EA as shown in FIG. The arc AB is arranged so as to irradiate up to the point B ′ near the lower end of the area CA. That is, the light beam reflected by the arcuate curved reflecting surface 21a in the vicinity of the joint A with the discharge tube receiving part 20 irradiates the point A ′ near the upper end of the effective irradiation area EA. In addition, a light beam emitted from the center of the discharge tube 16 is reflected by the joint B between the circular arc AB and the elliptical arc BC on the arc-shaped curved reflecting surface 16a, and the reflected light beam passes through a point B ′ near the lower end of the central area CA. Try to irradiate. The effective reflection area EA is a shooting screen range shot by the camera. Further, in the present embodiment, the central area CE is an area having a length (L1 / 2) that is ½ of the vertical irradiation length L1 in the effective reflection area EA, and the center of the central area CA is the effective reflection area. It coincides with the center of EA.
[0019]
The elliptical curved reflecting surface 22a has a longitudinal section constituted by an elliptical arc BC. The elliptical arc BC is connected to the circular arc AB so as to have a common tangent line at the joint A between the elliptical arc BC and the circular arc AB. The elliptical arc BC is arranged in such a direction that the arc connecting side has a large curvature and the straight line connecting side has a small curvature. And as shown in FIG. 3, the range of B'-C 'which is the lower end part vicinity of the said center area CE is irradiated with the light ray from the center of the discharge tube 16 reflected by this elliptical arc-shaped curved reflective surface 22a. As this elliptical arc BC, for example, the major axis diameter is 41.65 mm and the minor axis diameter is 13.18 mm, and the starting point angle is 5 ° 39 ′ counterclockwise with respect to the right intersection of the major axis and the ellipse. 36 ″ and an end point angle of 13 ° 8′27 ″ is used. However, the present invention is not limited to this, and the range from B ′ to C ′ near the lower end of the central area CE is irradiated. Anything is acceptable.
[0020]
The flat reflecting surface 23a has a vertical cross section formed by a straight line CD, and the straight line CD is tangent to the elliptical arc BC and is connected to the elliptical arc BC. Then, as shown in FIG. 3, a range C ′ of C ′ from the central portion D ′ of the central area CA to the lower end portion of the central area CA due to the light emitted from the center of the discharge tube reflected by the flat reflecting surface 23a. -D 'is irradiated.
[0021]
In FIG. 3, only the light beam emitted from the center P1 of the strobe discharge tube 16 is representatively described, and the light emitted from the entire strobe discharge tube 16 has a certain width centered on the illustrated light beam. It will be a thing.
[0022]
As shown in FIG. 1, the side reflecting portion 18 is composed of a pair of side plates 25 and 26 extending so as to be continuous with the upper and lower flat portions 23. These side plates 25 and 26 are bent so as to be perpendicular to the flat portion 23. The vicinity of the discharge tube receiving portion 20 and the arcuate curved portion 21 is cut away. As shown in FIG. 4, the ends of the discharge tube 16 protrude from the notches 27 and 28 to the outside of the reflector 15.
[0023]
As shown in FIG. 4, the side reflector 18 is disposed at an inclination angle θ <b> 2 with respect to the center line of the discharge tube 16 in a horizontal cross section through which the center of the discharge tube 16 passes. The light beam irradiates the effective irradiation area efficiently. Further, in order to effectively use the flash of the discharge tube 16, the discharge tube arc length L2 is made smaller than the discharge tube receiving portion length L3.
[0024]
As shown in FIG. 5, the reflector 15 configured as described above is attached to the strobe discharge tube 16 after being placed in the reflector case 30. Thereafter, a transparent protector 31 is attached to form the strobe light emitting unit 32.
[0025]
As shown in FIG. 6, a strobe unit 34 is configured by attaching a strobe light emitting unit 32 to a printed circuit board 33 in which a strobe circuit is incorporated as is well known. The printed circuit board 33 includes an electrical component such as a main capacitor 35, a battery 36, a pair of electrode plates 37a and 37b for connection to a strobe circuit, a sync switch 38, and contact surfaces 39a and 39b. Is provided. Contact pieces 39c are attached to the contact surfaces 39a, 39b so as to be freely contactable. The contact piece 39c comes into contact with the contact surfaces 39a and 39b by the pressing operation of the charge button 52, whereby charging of the main capacitor 35 is started.
[0026]
The strobe unit 34 is incorporated in a lens-fitted photo film unit 40. FIG. 6 is an exploded view of the lens-fitted photo film unit 40. The lens-equipped film unit 40 includes a main body base 42 into which a cartridge 41a of a film cartridge 41 and a photographic film 41b drawn from the cartridge 41a are loaded, and an exposure unit 43 and a strobe unit mounted on the front surface of the main body base 42. 34, a front cover 45 that is mounted on the front surface of the main body base 42, covers the exposure unit 43 and the strobe unit 34, and is mounted on the back side of the main body base 42, so that the photographic film 41b is optically sealed between the main body base 42 and the front cover 45. The rear cover 46 is housed.
[0027]
The exposure unit 43 is a unit obtained by assembling a counter mechanism for displaying the number of frames that can be photographed, a shutter mechanism, a one-frame feeding mechanism for feeding a photographic film one by one, a photographing lens 47, a finder 48, and the like. .
[0028]
The main body base 42 is provided with a cartridge chamber 42a in which the cartridge 41a is loaded, and a film storage chamber 42b for storing the unexposed photographic film 41b drawn out from the cartridge 41a and rolled. These bottom surfaces are openings and are closed by bottom lids 46 a and 46 b formed on the rear cover 46. The bottom lid 46a of the cartridge chamber 42a is freely opened and closed by claw engagement, and after the photographing of all the frames of the photographic film 41b is completed, a takeout lid for taking out the cartridge 41a containing the photographed photographic film 41b. Become.
[0029]
A winding knob 50 is rotatably arranged on the upper portion of the cartridge chamber 42a. By rotating the winding knob 50 in the counterclockwise direction in the drawing, the portion of the photographed photo film 41b is wound into the cartridge 41a, and the unexposed portion is pulled out from the film storage chamber 42b, so that the aperture 42c Set behind.
[0030]
A release button 51 is integrally formed on the upper surface of the front cover 45. In addition, an opening for exposing the photographing lens 47, the finder 48, and the strobe light emitting unit 32 is formed on the front surface of the front cover 45, and a charging button 52 is integrally formed.
[0031]
Next, the operation in this embodiment will be described. At the time of shooting, the discharge tube 16 emits light in synchronization with the shutter release operation. In addition to directly irradiating the effective irradiation area with the light from the discharge tube 16, the reflected light irradiates the effective irradiation area EA through the reflector 15, as shown in FIGS.
[0032]
The light reflected by the arcuate curved reflecting surface 21a irradiates a range A ′ to B ′ from A ′ near the upper part of the effective irradiation area EA to the lower part B ′ of the central area CA. The light reflected by the flat reflecting surface 23a irradiates a range D ′ to C ′ from the center D ′ of the central area CA to the vicinity C ′ of the lower end thereof. Furthermore, the light reflected by the elliptical arc-shaped curved reflecting surface 22a irradiates C ′ to B ′ near the lower end of the central area CA. As described above, the reflecting surfaces 21a, 22a, and 23a having the cross-section arc, the cross-section elliptical arc, and the cross-section straight line, in the vertical range of the effective irradiation area EA, near the upper limit thereof from A ′ to the lower end portions B ′ and C ′ of the central area range. The center area CA is irradiated up to the center D ′, so that the distribution of the reflected light can be made smooth and the center area can be sufficiently irradiated. Therefore, as compared with a conventional reflector having only a curved reflecting surface using an arc or an elliptical arc, the amount of light to the effective irradiation area can be increased by about 16% to 30%.
[0033]
In the above embodiment, the reflector 15 is configured by press-molding an aluminum plate. However, the metal plate to be used is not limited to the aluminum plate, and any other material can be used as long as it has conductivity and high reflectance. The metal plate may be used. Further, instead of press-molding the metal plate, a reflector may be constituted by a synthetic resin molded product, and a metal film may be deposited on the reflecting surface of the reflector. In this case, an aluminum plate may be attached to the discharge tube receiving surface to which the trigger voltage is applied.
[0034]
In the above embodiment, the arcuate curved portion 21 and the flat portion 23 having a straight cross section are continuously connected by the curved portion 22 having the elliptical cross section, but instead of the curved reflecting surface 22a having the elliptical cross section, a plurality of curvatures are different. You may use the composite circular arc surface which made the circular arc smoothly continue in order of curvature. Such a pseudo elliptical arc is also included in the elliptical arc in the present invention.
[0035]
In the above embodiment, the lens-fitted photo film unit 40 has been described. However, the present invention can be used for strobe devices used in various cameras. Further, the present invention is not limited to the strobe discharge tube, and the present invention may be applied to a reflector that reflects a straight tube fluorescent lamp, an ultraviolet lamp, or the like.
[0036]
【The invention's effect】
According to the present invention, the longitudinal cross-sectional shape continuous to the discharge tube receiving portion is configured by an arc, an elliptical arc, and a straight line in order, and the arcuate curved reflecting surface having the longitudinal cross-sectional shape of the arc and the longitudinal cross-sectional shape of the elliptical arc Since the elliptical arc-shaped curved reflecting surface and the flat reflecting surface having the straight vertical cross-sectional shape are provided, the light collection efficiency can be increased by changing the arrangement of these reflecting surfaces. In addition, light distribution depressions in the central area can be eliminated. By arranging the arcuate curved reflecting surface, the elliptical arcuate reflecting surface and the flat reflecting surface at a line symmetrical position with the strobe discharge tube as the center, the light collection efficiency can be further increased.
[0037]
Since the discharge tube receiving part is formed with a diameter larger than the strobe discharge tube and the forming angle of the discharge tube receiving part is set to 30 degrees or more with respect to the line symmetrical reference line, the trigger voltage is surely applied to the discharge tube. Can be done. In addition, since the formation angle of the discharge tube receiving portion is set within 60 degrees, the amount of re-light input to the discharge tube can be reduced.
[0038]
The straight line is the tangent line of the ellipse, and the flat reflecting surface is arranged so that light rays emitted from the center of the strobe discharge tube irradiate from the center of the central area of the effective irradiation area to the vicinity of the lower end of the central area. This makes it possible to illuminate the central portion of the photographing screen more brightly and eliminate the light distribution depression near the center. In addition, by bending the side reflection portions at both end edges of the flat reflection surface, the bent portion becomes a straight line, and press molding becomes easy. Also, since it is an elliptical tangent and only moves a straight line, it is easy to control the light beam and to design easily.
[0039]
The light beam that exits from the center of the strobe discharge tube and is reflected by the joint between the arc and the elliptical arc on the arc-shaped curved reflecting surface irradiates near the lower end of the central area, and the arc and the discharge tube receiving portion on the arc-shaped curved reflecting surface The arc reflected so that the light beam reflected by the joint line irradiates near the upper limit of the effective irradiation area, and the light beam reflected by other arc-shaped curved reflecting surfaces irradiates between the lower end of the central area and the upper limit of the effective irradiation area. Thus, the entire effective irradiation area can be irradiated and the central area can be irradiated, and the light collection efficiency can be increased.
[0040]
An elliptical arc is formed so that the light beam that emerges from the center of the strobe discharge tube and is reflected by the elliptical curved reflecting surface irradiates from the center of the central area to the lower end thereof, and is common to the joint between the elliptical arc and the circular arc. Since the elliptical arc is arranged so as to have the tangent line, the vicinity of the lower end of the central area can be focused on the entire effective irradiation area.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a strobe discharge tube reflector embodying the present invention.
FIG. 2 is a cross-sectional view showing a vertical cross-sectional shape of an upper half of the reflector.
FIG. 3 is an explanatory diagram showing irradiation to an effective irradiation area by each reflecting surface of the reflector.
FIG. 4 is a cross-sectional view showing a cross-sectional shape of the reflector.
FIG. 5 is an exploded perspective view showing a strobe light emitting unit.
FIG. 6 is an exploded perspective view showing a lens-fitted photo film unit.
FIG. 7 is a cross-sectional view showing a conventional strobe unit.
[Explanation of symbols]
15 Reflector 16 Strobe discharge tube 17 Circumferential reflector 18 Side reflector 20 Discharge tube receiver 21 Arc-shaped curved portion 21a Arc-shaped curved reflective surface 22 Elliptical curved portion 22a Elliptical curved reflective surface 23 Flat portion 23a Flat reflective surface 30 Reflector case 31 Transparent protector 32 Strobe light emitting unit 33 Printed circuit board

Claims (4)

A discharge tube receiving portion for applying a trigger voltage to the strobe discharge tube and a peripheral surface reflection portion continuous with the discharge tube receiving portion, and light emitted from the center of the strobe discharge tube by the peripheral surface reflection portion is In the strobe discharge tube reflector that illuminates the effective irradiation area that is the shooting screen range
The longitudinal cross-sectional shape of the peripheral surface reflection portion is constituted by an arc, an elliptical arc, and a straight line in order, and connected so as to have a common tangent at the joint of the circular arc and the elliptical arc, and the straight line is a tangent of the elliptical arc,
An arc-shaped curved reflecting surface having a vertical cross-sectional shape of the arc irradiates a range from an upper end of the effective irradiation area to a lower end of a central area in the vertical direction of the effective irradiation area, and an elliptical arc shape having a vertical cross-sectional shape of the elliptical arc Irradiating the vicinity of the lower end portion of the central area by a curved reflecting surface , irradiating the range from the vicinity of the lower end portion of the central area to the central portion of the central area by a flat reflective surface having the straight vertical cross-sectional shape ,
A strobe discharge tube reflector, wherein the arc-shaped curved reflection surface, the elliptical arc-shaped reflection surface, and a flat reflection surface are arranged at line symmetry positions with respect to a horizontal line passing through the center of the strobe discharge tube. The discharge tube receiving portion is formed to have a diameter equal to or greater than a strobe discharge tube diameter, and a forming angle of the discharge tube receiving portion is set in a range of 30 degrees to 60 degrees with respect to the line symmetry reference line. The reflector for strobe discharge tubes according to 1 . 3. The strobe discharge tube reflector according to claim 1, wherein the vertical length of the central area is half of the vertical length of the effective irradiation area, and the center of the central area is aligned with the center of the effective irradiation area. . It said discharge tube receiving portion, claims 1 to 3 any one strobe discharge tube reflector according is characterized in that formed longer than the arc length of the flash discharge tube.

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