Flash apparatus capable of varying emission angle

• US 6,011,929 A
• Filed: 07/25/1997
• Issued: 01/04/2000
• Est. Priority Date: 07/29/1996
• Status: Expired due to Term

• Current Assignee: Panasonic Photo & Lighting Co. Ltd. (Panasonic Holdings Corporation)
• Original Assignee: West Electric Company Limited
• Inventors: Horinishi, Katsumi, Kawabata, Katsunori, Fuke, Mitsuo
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): Dalakis, Michael
• Application Number:
  US08/900,296
• Time in Patent Office: 893 Days
• Field of Search: 396/155, 396/164, 396/175, 396/198, 396/200, 362/16, 362/18, 362/20
• US Class Current: 396/175
• CPC Class Codes: F21V 17/02 with provision for adjustment F21V17/04 - F21V17/08 take precedence
• CPC Class Codes: F21V 19/02 with provision for adjustment, e.g. for focusing
• CPC Class Codes: F21V 5/02 of prismatic shape F21V5/04 takes precedence
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 15/06 Special arrangements of screening, diffusing, or reflecting devices, e.g. in studio
• CPC Class Codes: G03B 2215/0528 movable reflector, e.g. change of illumination angle or illumination direction

Abstract

A flash apparatus capable of varying the emission angle according to the present invention is characterized in that a light controller provided in front of a reflector for diffusing or condensing supplied light is configured to comprise a diffusion controlling portion having light diffusive action only with respect to a longitudinal direction of a bar-like light source and a condensation controlling portion having condensing action to omnidirectionally condense supplied light. By this, the flash apparatus capable of varying the emission angle can control and restrict prism action at the light controller by diffusing light emitted from the bar-like light source in respect to the longitudinal direction of the bar-like light source even when the bar-like light source and the light controller are close to each other. As a result, unevenness of light distribution (rainbow-like unevenness) based on the prism action at the light controller can be prevented from occurring even in a state on the wide side when the light emitting portion is miniaturized.

Claims

1. A flash apparatus capable of varying the emission angle, comprising at least a bar-like light source disposed in a reflector and a light controller disposed in front of said reflector, and being capable of varying the light emission angle by changing the relative distance between said reflector provided with said bar-like light source and said light controller or the position of said bar-like light source with respect to said reflector, said apparatus being characterized in that

said light controller comprises:

a diffusion controlling portion having light diffusive action only with respect to the longitudinal direction of said bar-like light source; and

a condensation controlling portion having condensing action to omnidirectionally condense light supplied directly from said bar-like light source or via said reflector.

2. A flash apparatus capable of varying the emission angle, comprising at least a bar-like light source located in a reflector and a light controller located in front of said reflector, and being capable of varying the light emission angle by changing the relative distance between said reflector having said bar-like light source and said light controller or the position of said bar-like light source with respect to said reflector, and wherein

said light controller comprises:

a diffusion controlling portion comprising a concave cylindrical lens formed on an opposing face to the bar-like light source in a direction perpendicular to the longitudinal direction of said bar-like light source which has light diffusive action only with respect to the longitudinal direction of said bar-like light source; and

a condensation controlling portion or a Fresnel lens, formed on the other face as a ring-zonal lens having at least one vertex and formed by dividing a curved face of a lens into a plurality of concentric curved face portions and connecting said divided curved face portions together to each other at respective sections which has condensing action to omnidirectionally condense light supplied directly from said bar-like light source or via said reflector.

3. A flash apparatus capable of varying the emission angle as claimed in claim 2, wherein

the ring-zonal lens comprises a first condensation controlling portion and a second condensation controlling portion which are formed to be symmetrical with respect to a fiducial line which is across the center of the longitudinal length of the bar-like light source so as to be perpendicular to the longitudinal direction, each condensation controlling portion having one vertex and a ring-zonal lens curved face connected to the vertex, said vertexes being disposed so as to have a distance therebetween of 1/2 or less of the size of the aperture in the longitudinal direction of said reflector when a wide-angle photograph is taken with said apparatus.

4. A flash apparatus capable of varying the emission angle, comprising a bar-like light source disposed in a reflector and light controller disposed in front of said reflector, and being capable of varying the light emission angle by changing the relative distance between said reflector provided with said bar-like light source and said light controller or the position of said bar-like light source with respect to said reflector, said apparatus being characterized in that

said light controller comprises:

a first light controlling member provided in front of the reflector from the side of the bar-like light source and a second light controlling member which is provided in front of the first light controlling member;

said first light controlling member being composed of

a first concave cylindrical lens formed on an opposing face to the bar-like light source in the longitudinal direction of said bar-like light source and having light diffusive action with respect to a direction perpendicular to the longitudinal direction of the bar-like light source, and

a Fresnel lens provided with a ring-zonal lens formed on the other face, having at least one vertex and having condensing action to omnidirectionally condense light supplied directly from the bar-like light source or via the reflector, said ring-zonal lens being formed by dividing a curved face of a lens into a plurality of concentric curved face portions and connecting said divided curved face portions together to each other at respective sections;

said second light controlling member being composed of

a plate-like member provided with a second concave cylindrical lens formed on an opposing face to the ring-zonal lens in a direction perpendicular to the first, concave cylindrical lens.

7. A flash apparatus capable of varying the emission angle as claimed in claim 4, wherein

the ring-zonal lens comprises a first condensation controlling portion and a second condensation controlling portion which are formed to be symmetrical with respect to a fiducial line which is across the center of the longitudinal length of the bar-like light source so as to be perpendicular to the longitudinal direction, each condensation controlling portion having one vertex and a ring-zonal lens curved face connected to the vertex, said vertexes being disposed to have a distance therebetween of 1/2 or less of the size of the aperture in the longitudinal direction of said reflector when a wide-angle photograph is taken with said apparatus.

5. A flash apparatus capable of varying the emission angle, comprising at least a bar-like light source disposed in a reflector and a light controller disposed in front of said reflector, and being capable of varying the light emission angle by changing the relative distance between said reflector provided with said bar-like light source and said light controller or the position of said bar-like light source with respect to said reflector and, at the same time, by changing the size of an aperture of said reflector in the longitudinal direction of said bar-like light source to be narrower when said bar-like light source and said light controller approach to each other, said apparatus being characterized in that

said light controller is composed of:

a concave cylindrical lens formed on an opposing face to the bar-like light source in a direction perpendicular to the longitudinal direction of said bar-like light source and having light diffusive action only with respect to the longitudinal direction of said bar-like light source; and

a Fresnel lens provided with

a ring-zonal lens formed on the other face, having at least one vertex and having condensing action to omnidirectionally condense light supplied directly from the bar-like light source or via the reflector, said ring-zonal lens being formed by dividing a curved face of a lens into a plurality of concentric curved face portions and connecting said divided curved face portions together to each other at respective sections, and

a condensing lens formed in such a manner as not to cover the narrowed aperture of the reflector and having condensing action with respect to the longitudinal direction of the bar-like light source.

8. A flash apparatus capable of varying the emission angle as claimed in claim 5, wherein

the condensing lens comprises a strip-like lens formed by dividing a curved face of a lens having condensing action only with respect to the longitudinal direction of the bar-like light source into a plurality of curved face portions in the direction perpendicular to the longitudinal direction of said bar-like light source and by connecting said divided curved face portions together to each other at respective sections.

6. A flash apparatus capable of varying the emission angle, comprising a bar-like light source disposed in a reflector and a light controller disposed in front of said reflector, and being capable of varying the light emission angle by changing the relative distance between said reflector provided with said bar-like light source and said light controller or the position of said bar-like light source with respect to said reflector and, at the same time, by changing the size of an aperture of said reflector in the longitudinal direction of said bar-like light source to be narrower when said bar-like light source and a Fresnel lens approach to each other, said apparatus being characterized in that

said light controller comprises:

a first light controlling member provided in front of the reflector from the side of the bar-like light source and a second light controlling member which is provided in front of the first light controlling member;

said first light controlling member being composed of

a first concave cylindrical lens formed on an opposing face to the bar-like light source in the longitudinal direction of said bar-like light source and having light diffusive action with respect to a direction perpendicular to the longitudinal direction of the bar-like light source, and

a Fresnel lens provided with a ring-zonal lens formed on the other face, having at least one vertex and having condensing action to omnidirectionally condense light supplied directly from the bar-like light source or via the reflector, said ring-zonal lens being formed by dividing a curved face of a lens into a plurality of concentric curved face portions and connecting said divided curved face portions together to each other at respective sections;

said second light controlling member being composed of

a plate-like optical member provided with

a second concave cylindrical lens formed on an opposing face to the ring-zonal lens in a direction perpendicular to the first concave cylindrical lens, and

a condensing lens formed on the other face in such a manner as not to cover the narrowed aperture of the reflector and having condensing action with respect to the longitudinal direction of the bar-like light source.

9. A flash apparatus capable of varying the emission angle as claimed in claim 6, wherein the condensing lens comprises a strip-like lens formed by dividing a curved face of a lens having condensing action only with respect to the longitudinal direction of the bar-like light source into a plurality of curved face portions in the direction perpendicular to the longitudinal direction of said bar-like light source and by connecting said divided curved face portions together to each other at respective sections.

10. A flash apparatus capable of varying the emission angle as claimed in claim 6, wherein the ring-zonal lens comprises a first condensation controlling portion and a second condensation controlling portion which are formed to be symmetrical with respect to a fiducial line which is across the center of the longitudinal length of the bar-like light source so as to be perpendicular to the longitudinal direction, each condensation controlling portion having one vertex and a ring-zonal lens curved face connected to the vertex, said vertexes being disposed to have a distance therebetween of 1/2 or less of less size of the aperture in the longitudinal direction of said reflector when a wide-angle photograph is taken with said apparatus.

11. A flash apparatus capable of varying the emission angle, comprising at least a bar-like light source disposed in a reflector and a light controller disposed in front of said reflector, and being capable of varying the light emission angle by changing the relative distance between said reflector provided with said bar-like light source and said light controller or the position of said bar-like light source with respect to said reflector, said apparatus being characterized in that

said light controller comprises:

a diffusion controlling portion comprising a concave cylindrical lens having light diffusive action only with respect to the longitudinal direction of said bar-like light source; and

a condensation controlling portion having condensing action to omnidirectionally condense light supplied directly from said bar-like light source or via said reflector.