JP4470542B2 - Lighting device - Google Patents

Description

  The present invention relates to an illuminating device having a light source and a reflecting member, and has improved light distribution characteristics.

  An electronic flash device used for a camera generally includes a light emitting unit including a flash discharge tube and a reflective shade, and a light emitting circuit for controlling light emission of the flash discharge tube. A Fresnel lens (condenser lens) is provided in front of the light emitting section, and flash light emitted from the discharge tube is partly directly reflected by the reflecting shade and incident on the Fresnel lens. Illuminates the subject. The reflection shade is composed of a curved portion having a curved surface that covers the top and bottom and the back of the discharge tube, and a pair of side plate portions respectively disposed on both sides of the curved portion. The reflected light from the curved part mainly contributes to the illumination of the central part of the subject, and the reflected light from the pair of side plates is irradiated in the direction crossing each other, so that the left and right parts of the subject are mainly (in the case of vertical position shooting) Contributes to lighting of the upper and lower parts.

JP-A-6-130468 JP 2002-75009 A

  However, with the conventional reflecting shade structure, the reflected light of the pair of side plates cannot be widened, so that the amount of light in the portions corresponding to the four corners of the shooting screen tends to be insufficient, especially at wide angle shooting. Sometimes this is noticeable.

The present invention is directed to a first direction across a light source, a main reflection portion that reflects light from the light source toward an irradiation target, and that mainly contributes to illumination of a central portion of the irradiation target, and an optical axis of the illumination light. The light source is applied to an illuminating device having a pair of side reflecting portions that are arranged apart from each other and reflect light in a direction crossing each other to contribute to illumination on both sides of the irradiation target. Each side reflecting portion has at least two kinds of reflecting surfaces arranged with an optical axis in a second direction orthogonal to the first direction, and the reflected lights of these two kinds of reflecting surfaces cross each other. Configured to be directed toward the subject.
According to a second aspect of the present invention, each of the side reflecting portions is disposed at an angle with respect to the first reflecting surface substantially parallel to the second direction and the first reflecting surface with the optical axis in between. And the third reflection surface, and the reflected light from the second and third reflection surfaces is configured to cross each other.
In the invention of claim 3, the main reflecting portion and the pair of side reflecting portions are integrally formed by bending one reflecting plate member.

  According to the present invention, each of the pair of side reflecting portions is provided with at least two kinds of reflecting surfaces arranged so as to sandwich the optical axis in a second direction orthogonal to the arrangement direction (first direction). Since the reflected lights of the two kinds of reflecting surfaces cross each other and go to the subject side, the reflected light at each side reflecting portion can be spread in the second direction, and the irradiation area can be It becomes possible to enlarge.

An embodiment in which the present invention is applied to an external electronic flash device for a camera will be described with reference to the drawings.
The electronic flash device is attachable to and detachable from the upper surface of a camera (not shown), and illuminates the subject by flashing the light emitting unit in response to a signal input from the camera side.

  The light emitting part of the electronic flash device is shown in FIGS. The light emitting unit includes a flash discharge tube (hereinafter referred to as a discharge tube) 10 such as a xenon tube, and a reflection shade 20 that reflects flash light emitted from the discharge tube 10 toward the subject side. In the figure, Z is the optical axis of the illumination light, X is the longitudinal axis (perpendicular to the Z axis) of the discharge tube 10, and Y is the axis orthogonal to both the Z axis and the X axis. When the camera is held at the normal horizontal position, the X-axis direction is the camera horizontal direction, and the Y-axis direction is the camera vertical direction.

The reflection shade 20 is formed by bending a single metal plate having a predetermined reflectance, and includes a curved portion 21 having a curved reflective surface and a pair of side reflections located on both sides of the curved portion 21 in the X-axis direction. Part 22. Each side reflection part 22 is comprised by bending the part (4 places) which protruded from the curved part 21, and the surface inside the bending part 22a turns into a reflective surface. The tip of each bent portion 22a is further bent outward to form a bent portion 22b. As a result, each side reflecting portion 22 is disposed at an angle with the first reflecting surface P1 parallel to the Y-axis and the first reflecting surface P1 across the optical axis Z, respectively. It has reflection surfaces P2 and P3.
Although a Fresnel lens is disposed in front of the light emitting unit, its illustration is omitted.

  As shown in the figure, the flash discharge tube 10 is disposed so as to penetrate the rear of the pair of side reflection portions 22, whereby the curved reflection surfaces cover the top and bottom and the back of the discharge tube 10, and the pair of side reflection portions 22 includes the discharge tube. 10 are placed on the left and right with the optical axis Z in between.

Next, the difference in light distribution characteristics between the reflective shade 20 in the present embodiment and the conventional reflective shade will be described.
5 and 6 show the light distribution characteristics of the reflective shade 20 of this embodiment. In the figure, x and y are horizontal and vertical central axes in the subject illumination range, and X and x, and Y and y are in parallel to each other. S indicates a subject in the shooting screen. On the other hand, FIG. 7 shows a conventional reflective shade 120, and its light distribution characteristics are shown in FIGS. In the conventional type, only the first reflecting surface P1 parallel to the Y axis is provided on the side reflecting portion 122.

  When the discharge tube 10 emits light, the irradiated light is reflected directly or by the reflection shade 20 (120) and enters the Fresnel lens, and the transmitted light of the Fresnel lens is irradiated to the subject side. The light c1 to c3 in FIGS. 5 and 8 indicate direct light that does not pass through the reflective shade. The direct light and the reflected light from the curved portion 21 of the reflecting shade 20 mainly contribute to the illumination of the central portion in the x-axis direction, and the reflected lights from the pair of side reflecting portions 22 (122) intersect each other. Is mainly contributed to illumination on both sides in the x-axis direction. This is the same in this embodiment as well as in the prior art.

  Now, paying attention to the light a guided to the lower part of the both-side reflecting portion 22 (122) in the irradiation light of the discharge tube 10, in the conventional example of FIG. 8, the light a is reflected by the reflecting surface P1, and the reflected light a1 ′ is Crossing each other and irradiating almost on the x-axis. Further, the light irradiated upward in symmetry with the light a with respect to the X axis is similarly reflected by the reflecting surface P1 and irradiated almost on the x axis. This means that in the conventional reflecting shade, the reflected light of the side reflecting portion 122 hardly spreads in the y-axis direction across the x-axis, and therefore the irradiation distribution is as shown by the contour line 51 ′ in FIG. . In other words, the light does not go around the four corners P1 to P4 of the screen, resulting in dark pictures at the four corners.

On the other hand, in the present embodiment, a reflection surface P2 having a different angle from the reflection surface P1 is provided at the location where the light a is irradiated, and the reflected light a1 is as shown in FIGS. Advancing and irradiating a position offset upward from the x-axis. Further, light irradiated upward in symmetry with the light a with respect to the X axis is reflected by the reflecting surface P3, and the reflected light b1 (FIG. 5 ) intersects with the reflected light a1 and is offset downward from the x axis. The position is irradiated. This reflected light of the side reflection part 22 of the present embodiment, means that has a spread in the y-axis direction across the x-axis in comparison with the conventional screen as shown in contour lines 51 in this order 6 As the light wraps around the four corners P1 to P4, the entire screen is illuminated brightly. In addition, the reflection surfaces P2 and P3 for expanding the irradiation range can be formed only by bending the conventional side reflection part, and no separate member is required, so that an increase in cost can be suppressed to a minimum.

  In addition, what is necessary is just to adjust suitably the area and angle of reflection surface P2, P3 of each side reflection part according to the desired light distribution characteristic. Moreover, the side reflection part which has only the reflective surfaces P2 and P3 may be sufficient, or you may make it obtain the same effect by making a side reflection part into a curved surface. Further, the side reflection portion may be formed separately from the curved portion.

  Although an external electronic flash device for a camera has been described, the present invention can also be applied to an electronic flash device built in a camera. Furthermore, as long as it has a light source and a reflecting member, it can be applied to an illumination device other than the electronic flash device.

The perspective view which shows the light emission part of the electronic flash apparatus in one Embodiment of this invention. The figure which looked at the said light emission part from the Z-axis front. The figure which looked at the said light emission part from the Y-axis upper direction. The figure which looked at the said light emission part from the X-axis side. The figure explaining the direction of the irradiation light of a light emission part. The figure which shows the light intensity on the contour line which shows the light intensity distribution on a to-be-photographed object with an electronic flash device, and an x-axis and a y-axis. The perspective view which shows the light emission part of the conventional electronic flash device. The figure which shows the direction of the irradiation light in the conventional electronic flash device. The figure which shows the light intensity on the contour line which shows the light intensity distribution on the to-be-photographed object by the conventional electronic flash device, and the x-axis and the y-axis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flash discharge tube 20 Reflection shade 21 Bending part 22 Side reflection part 22a, 22b Bending part P1 1st reflection surface P2 2nd reflection surface P3 3rd reflection surface

Claims (3)

A light source;
A main reflection part that reflects the light from the light source toward the irradiation target and mainly contributes to illumination of the central part of the irradiation target;
A pair of side reflections that are arranged apart from each other in the first direction across the optical axis of the illumination light, and mainly contribute to illumination on both sides of the irradiation target by reflecting the light from the light source in the direction crossing each other. In a lighting device having a portion,
Each of the side reflecting portions has at least two kinds of reflecting surfaces arranged with the optical axis in a second direction orthogonal to the first direction, and the reflected light of the two kinds of reflecting surfaces is An illuminating device configured to cross each other toward a subject side.   Each of the side reflecting portions is disposed at an angle with a first reflecting surface substantially parallel to the second direction and the first reflecting surface across the optical axis. The illumination device according to claim 1, wherein the reflected light from the second and third reflective surfaces intersects each other.   The lighting device according to claim 1, wherein the main reflection portion and the pair of side reflection portions are integrally formed by bending a single reflector member.

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