JPH08334811A - Photographic illuminator and camera with same - Google Patents

Abstract

PURPOSE: To efficiently converge light and to reduce a thickness, in a photographing illuminator such as a flashing device used for a camera. CONSTITUTION: A flashing part, composed of a flashing tube 3 and a reflector 4 for regulating the flashing direction of the flashing tube 3 is arranged in the upper part of a camera main body 1, so that the flashing direction of the flashing part is inclined toward a photographing optical axis. In the front part of the flashing part, a cover member 5 turnably supported by a hinge means covers a photographic lens barrel part 2, in a housing state and held in front of the reflector 4, in a photographing state and a reflection plate 7 is fixed on the inside surface side of the cover member 5. An optical panel 6 which is turnably supported on one end, housed in the cover member 5, in the housing state and inclined and fixed at a fixed angle with the flashing part, in the photographing state is provided in front of the reflection plate 7 and a fine Fresnel prism surface 6a is formed on the side surface of the flashing part, of the optical panel 6, to make irradiation efficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for photography which efficiently controls light emitted from a light source during photography.

[0002]

2. Description of the Related Art Conventionally, a lighting device of this type has been disclosed in Japanese Patent Laid-Open No. 1-9.
As described in Japanese Patent No. 433, the lid for covering the front surface of the photographing optical system is rotated and lifted, and the light from the built-in flash device is reflected on the inner surface of the lid to project the light on a subject. There is. Further, as a known example of preventing red eye during flash photography, as described in Japanese Utility Model Application Laid-Open No. 56-23926, a flash illuminator is built in a cover of a photographing lens, and the cover is rotated by a rotating mechanism of a camera. In some cases, the light emitting portion of the flash light emitter can be set apart from the optical axis of the lens of the camera by moving.

[0003]

However, in the above-mentioned conventional example, since the light from the built-in flash light emitting device is configured to change the direction by the reflecting plate provided on the inner surface of the lid, there are the following drawbacks. (1) If an attempt is made to collect light from the built-in flash device without leaking, the reflector will become extremely large. Alternatively, the thickness becomes thicker, which is difficult to actually carry out. Therefore, when commercialized, a part of the light from the flash tube was thrown out of the required irradiation angle. Especially, the luminous flux in the longitudinal direction of the flash arc tube could hardly be controlled.

(2) Basically, all the light beams are reflected by the reflecting plate to change the direction, so that the light amount is reduced by the reflectance. As for the red eye, the effect is insufficient because there is a component reflected at a portion close to the camera.

(3) In particular, in the latter conventional example described above, since the flashlight emitter is located at the tip of the cover, the mounting form is such that high-voltage lead wires are laid out, the rotating mechanism becomes complicated and large, assembly becomes difficult, and the cost increases. In addition, there is a risk of electric shock, and there is a problem that electrical energy is lost due to an increase in resistance due to the lengthening of the lead wire and the amount of light decreases.

The present invention as set forth in claims 1 to 3 eliminates the above-mentioned drawbacks of the prior art, efficiently collects the light emitted from the light source, and makes it possible to make the light emitting surface a thin surface light source. An object is to provide a lighting device for photographing.

According to the present invention as set forth in claims 4 and 5, in addition to high efficiency, surface emission and thinning of the light emitting portion, in the case of a camera with a built-in flash light emitting portion, the flash light emitting portion is used for photographing light due to red eye phenomenon. An object of the present invention is to provide a camera having a lighting device for photography that can avoid various problems caused by being separated from the axis. Similarly, it is an object of the present invention to provide a lighting device for photography which can be externally attached to a camera, which can increase the degree of freedom in designing the arrangement of components in the flash light emitting section.

[0008]

In order to achieve the above-mentioned object, the illuminating device for photography of the present invention as defined in claim 1 comprises a flash arc tube and a reflection shade for controlling the light emitting direction of the flash arc tube. The flash light emitting portion and an optical panel facing the irradiation direction of the flash light emitting portion and having a plurality of fine prism surfaces formed at least on the flash light emitting tube side are arranged to be inclined with respect to the flash light emitting portion. According to the present invention as defined in claim 2, the opening other than the reflection shade and the optical panel is covered with a reflection plate. Further, according to the present invention as defined in claim 3, the arrangement of the flash light emitting portions and the shape of the optical panel satisfy the following relational expression. 0 ≦ α _n , β _n , θ ≦ 90 ° α _n + β _n −θ> 0 θ ≧ α _n , θ + β _n > 90 ° θ <α _n , θ + β _n −sin ⁻¹ {sin (θ− α
_n ) / n}> 90 °, where θ is the angle between the light beam direction of the light source and the horizontal direction, α _{n is} the inclination of the n-th Fresnel prism entrance surface, and β _{n is} the inclination of the n-th Fresnel prism total reflection surface. , N: Refractive index of the material of the optical panel.

Similarly, in the camera of the present invention as defined in claim 4, a flash light emitting portion comprising a flash light emitting tube and a reflecting shade for restricting the light emitting direction of the flash light emitting tube is built into the camera body, and at least in a photographable state, the flash light emitting portion. An optical panel which is positioned in a state of being inclined with respect to the front surface of the light emitting portion and has a plurality of fine prism surfaces formed on at least the flash light emitting portion side, and is configured to cover openings other than the flash light emitting portion and the optical panel portion. The illuminating device for photography having a light redirecting member made of the above-mentioned reflection plate. Further, according to the present invention as set forth in claim 5, the light direction changing member arranged on the front surface of the flash light emitting portion is rotatably supported and can be stored when the camera is carried, and the back surface is used to function as a camera protection member. To do.

Similarly, the present invention according to claim 6 is an optical system in which a flash light emitting tube, a reflecting shade for controlling the light emitting direction of the flash light emitting tube, and a plurality of fine prism surfaces are formed at least on the surface side for receiving the flash light emission. It is a camera-mountable illumination device that is composed of a flash light emitting unit in which a panel is inclined with respect to a light emitting optical axis. Similarly, in the present invention as set forth in claim 7, in a lighting device for photography which can be attached to a camera, a reflection plate is formed by extending a part of a surface of the reflection shade so as to face a prism surface of the optical panel. Is.

[0011]

According to the present invention having the above-mentioned structure, each light ray is totally reflected by each fine prism surface of the optical panel and the light direction is converted into a predetermined angle direction. Is extremely small, and since each ray is received by the tilted optical panel, the final light exit surface, the optical panel, can be used in a large area, and as a result, a soft light source can be obtained by making it a surface light source. Therefore, the entire shape of the light emitting portion can be made extremely thin. Further, according to the present invention as set forth in claim 3, by satisfying a predetermined conditional expression, it is possible to well prevent the light amount loss due to the light emission in the flash light emitting section.

In addition to the above-mentioned functions, the present invention having the above-mentioned structure has a flash light emitting portion built into the camera body, so that the light emitting portion is separated from the lens barrel portion, so that the red eye phenomenon is prevented. However, the optical panel and the light direction changing member are compactly accommodated as a lens barrier in the accommodated state.

Further, according to the present invention as defined in claims 6 and 7, the degree of freedom of layout is increased as a flash device externally attached to the camera, and it is possible to provide a compact flash device having a surface emitting portion which has not been considered in the past. Become.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
Description will be made based on 0. FIG. 1 is a side view of a camera in use showing a main part of the present embodiment in cross section, FIG. 2 is a side view of the same in a stored state, FIG. 3 is an exploded perspective view of a flash light emitting part thereof, and FIG.
FIG. 3 is a cross-sectional shape of a reflection shade of the flash light emitting portion and a ray trace diagram thereof. In the figure, 1 is a camera body, and 2 is a taking lens barrel. Reference numeral 3 denotes a flash light emitting tube as an auxiliary light source for photography, which is built in the upper part of the camera body 1, and 4 has a rectangular parallelepiped opening edge for collecting the light generated from the flash light emitting tube 3. With a parabolic reflector,
Its cross-sectional shape is composed of three quadratic curved surfaces having different characteristics, which are a reflecting surface 4a at the rear end portion, reflecting surfaces 4b at both sides of the rear portion, and a front parabolic reflecting surface 4c. The reflection surface 4a reflects a light beam emitted from substantially the center of the flash arc tube 3, and in consideration of refraction when passing through the flash arc tube 3 again, the light beam after the final arc tube (glass tube) has passed is reflected. It is a curved surface that is corrected so as to be emitted as a component that is nearly parallel to the optical axis direction of the flash light emitting unit. Further, the reflecting surface 4b is a portion for controlling a component emitted obliquely rearward of the flash tube 3, and since the reflected light at this portion is largely influenced by refraction by the glass tube, a cylindrical surface concentric with the flash tube is provided. Then, the reflected light beam is returned to the central portion where the influence of refraction is small, and the reflecting surface 4c in front of the flash arc tube 3 is set.
It is configured to be controlled by. The reflecting surface 4c is a part in front of the center position of the flash tube 3 and is a parabolic surface having the center position of the flash tube 3 as a substantially focal position.

The reference numeral 5 functions as a lens barrier that covers the entire photographing lens when the camera is in a housed state, and is rotated by a hinge shaft 1a provided at an upper portion of the camera body 1 in a used state, in front of an opening edge of the reflection shade 4. It is a lid member that is connected and retained.

A reference numeral 6 is stored in the lid member 5 in a housed state of the camera, and is rotated about an upper hinge shaft (not shown) by a mechanism member (not shown) in a used state and held and fixed at a predetermined angle. As shown in FIGS. 1 and 3, an optical panel having the same shape as the lid member 5 and a trapezoidal outer shape has a Fresnel-shaped fine prism surface 6a at least on the upper surface on the light emitting portion side and a lower portion (close to the reflection shade). ) Is formed with a flat surface 6d, and the lower surface (close to the reflective shade) has a prism surface 6b on the subject side.
A flat surface 6c is formed on each of the upper portions thereof, a short side thereof has a width with a certain amount of margin in the length of the reflection shade 4 in the longitudinal direction, and a long side of the side surface reflection plate described later. 8
The width is almost the same as the distance between a and 8b.

Reference numeral 7 is a reflector fixed to the inner surface side of the lid member 5, and has a bright surface formed on the surface side facing the optical panel 6, and the usage state of the lid member 5 is on both side edges thereof. Side reflector 8 having a width narrowing toward the tip to prevent light from leaking from the light emitting space formed by the turning to
A and 8b are formed to be foldable. And
The side surface reflecting members 8a and 8b are folded inward when the camera is housed, and are opened substantially perpendicularly to the reflector 7 when used.

The operation of this embodiment having the above configuration will be described. First, as shown in FIG. 2, in the camera housed state, the taking lens barrel 2 is in the collapsed state, and is housed in the camera body 1 in the shortest state. In order to prevent the lens barrel portion 2 from being inadvertently touched from the outside by deterioration of optical characteristics due to dirt and scratches and failure due to deformation due to external force, the front portion is covered with the lid member 5 and functions as a so-called barrier. are doing. On the other hand, as will be described later, various members forming an optical system for changing the light emitting direction of the flash light emitting unit are housed inside the lid member 5 in a form that can fit in the minimum space.

Next, when the usage state shown in FIG.
First, when the photographer manually rotates the lid member 5 outward about the hinge shaft 1a, a switch (not shown) that detects this rotation turns on a main switch (not shown). As a result, the lens barrel portion 2 moves from the collapsed state to the image capturing position. At this time, the rotation detecting means outputs the predetermined hospital number only when the rotation detecting means moves to a position where it does not interfere with the protruding portion of the lens barrel 2.

Then, with the rotation of the lid member 5, the optical panel 6 rotates about the hinge shaft (not shown) in the upper portion of FIG. Then, in a state where the lid member 5 is rotated to the opening of the reflection shade 4, the lid member 5 is fixed and held at a predetermined opening angle. On the other hand, the side surface reflectors 8a and 8b also rotate in conjunction with the rotation of the lid member 5, and when the lid member 5 is rotated to a predetermined position, as shown in FIGS. On the other hand, it opens so as to rise almost vertically, and forms a light emitting space that covers the opening of the reflection shade 4 formed by the optical panel 6, the reflection plate 7, and the side reflection plates 8a and 8b. With such a structure in which light does not leak, it is possible to effectively collect the light emitted in the longitudinal direction of the flash light emitting tube, which was wastefully discarded in the structure of the conventional flash light emitting unit, and guide it within a predetermined irradiation angle. .

On the other hand, since the Fresnel prism surface 6a of the optical panel 6 is formed on the flash light emitting portion side, it is efficiently condensed by utilizing total reflection. Then, the light striking the reflecting shade 4 by the flash light emitting tube 3 arranged in the vicinity of the focal position of the reflecting shade 4 which is almost a paraboloid travels in a direction substantially parallel to the optical axis, and the Fresnel prism surface of the optical panel 6 is reached. Although the light direction is controlled by the total reflection on the Fresnel prism surface 6a, it is difficult to control the direct light from the flash tube 3 on the Fresnel prism surface 6a side. Further, it is controlled only by refraction of the Fresnel prism surface 6b on the object side. That is, direct light from the flash arc tube 3 is controlled by refraction at the lower Fresnel prism surface 6b, and reflected light at the reflection shade 4 is separately controlled by using total reflection at the upper Fresnel prism surface 6a. Therefore, it is possible to collect light efficiently.

Next, the inclination of the optical panel 6 and the inclination of the optical axis of the reflection shade 4 when the camera is used will be described. This angle is affected by the physical size of the optical panel 6, the size of the reflection shade 4, the effective diameter of the flash tube 3 and the like that can be allowed as the flash section. In addition, there are restrictions due to the overall design of the camera, as well as the optical panel 6 and the reflector 7.
When there is no light emitting direction changing part made up of, for example, the light emitting part made up of the flash light emitting tube 3 and the reflection shade 4 is used for bounce light emission, it cannot be uniquely determined from the viewpoint of other specifications. However, there is a minimum numerical constraint in constructing the light emitting unit, and as shown in FIGS. 1 and 3, the optical axis of the flash light emitting unit is slightly tilted forward from the vertical direction, and The inclination is smaller than this inclination, and the reflection plate 7 preferably connects the rear edge of the reflection shade 3 and the tip of the optical panel 6. A detailed numerical explanation will be given later.

Next, the shapes of the side reflectors 8a and 8b will be described in detail. As shown in FIG. 3, the side reflectors 8a and 8b have substantially the same length on the side close to the flash tube 3 side as the short side of the opening of the reflection shade 3 and on the far side the optical panel 6 and the reflector 7 are upper parts. The shape of the reflection plate 7 is a substantially triangular shape with a narrow width that fills a portion that substantially intersects with each other, and the reflection surface of this triangular reflection surface expands as the distance from the opening of the reflection shade 4 increases.
By tilting along the outer shape of the side reflector 8a,
The light flux after reflection at 8b can be condensed. The optimum angle of this inclination is determined by the required irradiation angle.

Although the reflector 7 and the side reflectors 8a and 8b are flat in this embodiment, the form is not limited to a flat shape, and may be a concave surface or a convex surface depending on the required irradiation angle. It may be formed, and in particular, if the reflecting plate 7 is shaped to match the shape of the lid member 5, space efficiency is good.

Next, the state of the light rays from the flash arc tube 3 will be described with reference to FIGS. 4 and 5. Due to the structure of the reflecting surface of the reflecting shade 4, as shown in FIG. 4, the luminous flux emitted from almost the center of the flash luminous tube 3 is excluded except for the luminous flux directly emitted without passing through the reflecting shade 4. Is emitted as a light beam substantially parallel to the optical axis of the flash light emitting section. In this way, the Fresnel prism surface 6 formed on the upper side of the optical panel 6 which is emitted parallel to the optical axis of the flash light emitting portion.
It is incident on a.

This incident condition will be described with reference to FIG. here,
The surface of the Fresnel prism surface 6a facing the arc tube side is 6
a ₁ , the opposite surface 6a ₂ , the Fresnel prism surface 6a
The back side (subject side) plane of 6c is designated as 6c. The light flux emitted from the reflecting shade 4 is aligned in the optical axis direction of the reflecting shade 4 and advances,
With respect to this emission direction, the optical panel 6 is tilted inward by a predetermined angle from the optical axis of the flash light emitting unit so that it can be received by a wide plane.
To place.

Next, regarding the behavior of light rays on each surface of the Fresnel prism of the optical panel 6, first, the surface 6a on the side of the arc tube is shown.
By refracting at ₁ , the light direction is tilted to the subject side, totally reflected by the surface 6a ₂ on the opposite side, refracted by the back side flat surface 6c of the optical panel 6, and then the luminous flux is controlled so as to proceed substantially parallel to the photographing optical axis. With this configuration, the light flux emitted from the reflecting shade 4 can be received on a wide surface and the light can be controlled.
Since the light controllability is good and the total reflection is used, the direction can be efficiently changed without causing the loss of the light amount due to the reflectance generated by the reflecting plate or the like. Further, since the direction is changed by each fine Fresnel prism surface, there is an advantage that the direction change can be completed within an extremely thin range.

On the other hand, looking at the direct light that cannot be controlled by the above-mentioned structure, first, the Fresnel prism 6b on the object side is shown.
The light flux passing to the side is refraction-controlled by the Fresnel prism 6b provided on the subject side. That is, the direct light from the flash arc tube 3 is directed to the flat surface 6 on the lower side of the optical panel 6 on the light emitting portion side.
The light is incident on the d side and refracted, is bent toward the subject, is further refracted by the Fresnel prism 6b provided on the subject side, and is converted into a light flux substantially parallel to the photographing optical axis. Further, the light flux passing through to the reflecting member 7 side is reflected by this reflecting surface, and after the exit angle is brought close to the flash light emission optical axis direction, the light is redirected by the Fresnel prism 6a surface on the upper side of the optical panel 6 to the subject direction. Is ejected. The light flux that cannot be completely controlled by the reflection shade 4 in this way is also converted into a component that almost goes to the subject through the lower Fresnel prism 6b surface and the reflection plate 7.

FIG. 6 shows how the luminous flux emitted from the flash tube 3 is directed toward the subject by the above operation. In the figure, the light beam shown by the solid line 10a is the reflected light component whose direction is aligned by the reflection shade 4, and the light beam shown by the alternate long and short dash line 10b is directly from the flash arc tube 3 to the Fresnel prism 6.
Both components are components corresponding to b, and as described above, both components are converted by the optical panel Fresnel prism into components that are substantially parallel to the photographing optical system. On the other hand, the chain double-dashed line 1
The luminous flux indicated by 0c is a component which strikes the reflector 7 directly from the flash tube 3. Unlike the former, as shown in the figure, the light cannot be controlled parallel to the photographing optical axis, but the light direction can be converted as a component within the required irradiation angle via the Fresnel prism 6a.

Next, the inclination of the optical panel 6 with respect to the optical axis of the flash light emitting portion, the inclination of the optical panel 6 with respect to the photographing optical axis, and the angle setting values of the respective inclined surfaces of the Fresnel prism of the optical panel 6 will be described with reference to FIGS. A description will be given using 10. First, FIG. 7 is an explanatory view of the angular relationship of the optical panel 6,
For ease of explanation, the optical panel 6 is set upright. First, when the configuration of the present embodiment is used as an illumination device for photography, the entire optical system is actually rotated so that the luminous flux after exiting the Fresnel prism coincides with the optical axis of the imaging optical system. It is necessary to arrange them.

In FIG. 7, P indicates the direction of the light source, so it is a position of the light source that is determined for convenience, and each set angle and the refractive index of the optical material are set as follows. θ: The angle between the luminous flux direction of the light source and the horizontal direction,
0 <θ ≦ 90 ° α _n : inclination of the n-th Fresnel prism entrance surface, β _n : inclination of the n-th Fresnel prism total reflection surface, and n: refractive index of the material of the Fresnel prism. First, regarding the necessary conditions of each set value for constructing the present invention, α _n and β _n are preferably in the following ranges due to processing restrictions of the Plenel prism. 0 ≦ α _n ≦ 90 ° ··· (1-1) 0 ≦ β _n ≦ 90 ° ··· (1-2)

Next, referring to FIG. 8, an optimum angle for the light flux 11 aligned in one direction by the reflector 4 to enter the Fresnel surface will be described. As shown in the figure, three types of optical paths are conceivable even for rays incident from the same direction depending on the position of the light source and the setting of the Fresnel angle. First,
The light ray 11a is the Fresnel prism entrance surface 6 of the optical panel 6.
The light enters from a ₁ and directly reaches the exit surface 6c without passing through the total reflection surface 6a ₂ . Exit surface 6c as shown
Although the light is not emitted from, and is almost totally reflected, it may be refracted and emitted depending on the position of the light source.

The light ray 11b is incident on the incident surface 6a ₁ and is the total reflection surface 6a _{2 in} the optical path intended by the present invention.
Is a component that is refracted and emitted at the emission surface 6c after total reflection at.
Finally, the light ray 11c is a component that enters from the total reflection surface 6a ₂ and exits from the exit surface 6c without passing through the surface 6a ₁ . From the above situation, the light rays 11a and 11c
It is necessary to set the incident direction of the light source and the shape of the Fresnel surface so as to reduce as much as possible. Actually, there is a certain amount of variation in the direction of the incident ray, so considering this point,
It is necessary to determine the inclination and pitch spacing of the Fresnel surface.

Regarding the ideal numerical condition, first, in order to prevent the light ray 11c from directly hitting the total reflection surface 6a ₂ , the direction of the light ray and the Fresnel surface may be set as follows. θ ≧ 90 ° -β _n ··· (2)

The following conditions must be satisfied in order to use even the light beam originally entering from the incident surface 6a ₁ as an effective light beam. This condition will be described with reference to FIG. FIG. 9 is an enlarged view of a ray trace in an ideal state, where a to d represent the angle components shown below. First, as the first condition, a necessary condition for not causing a light ray that does not hit the total reflection surface 6a ₂ like the light ray 11a shown in FIG. 8 is that the light ray after being refracted by the incident surface 6a ₁ is a total reflection surface. It is necessary that the light beam intersects with 6a ₂ , that is, the light beam after refraction rises from the inclination of the total reflection surface 6a ₂ .
Therefore, in FIG. 9, the minimum condition is b> a ... (3). If this relationship is expressed by the constants given up to now, θ + sin ⁻¹ {sin (θ−α _n ) / n}> 90 ° −β _n · (3) ′. If this condition is satisfied, the light can be guided to the total reflection surface 6a ₂ without fail by appropriately selecting the pitch of the Fresnel prism.

Next, a condition for total reflection of the light striking the total reflection surface 6a ₂ is required. That is, in FIG. 9, ∠c ≧ critical angle ... (4) is required. When this relationship is expressed by the constants given so far, 180 ° − (α _n + β _n ) −sin ⁻¹ {sin (θ−α _n ) / n} ≧ sin ⁻¹ (1 / n) ··· (4 ) ′

Finally, it is necessary that the light striking the exit surface 6c is not totally reflected. | D | <critical angle ··· (5) Similarly, when expressed in a form organized by given constants, | 180 ° + θ-2 (α _n + β _n ) -sin ⁻¹ {sin (θ−α _n ) / N} | <sin ⁻¹ (1 / n) ··· (5) ′ The above are the necessary conditions for the respective constants so as not to cause the light amount loss.

To summarize the above conditions more simply, first, the respective angles are expressed by the following equation (1): 0 ≦ α _n , β _n , θ ≦ 90 ° (6) Further, the conditional expression (4) for the total reflection surface is given. And from (5), α _n + β _n −θ> 0 ··· (7) Further, from the conditional expressions (2) and (3), when θ ≧ α _n , θ + β _n > 90 ° ··· (8-1) θ <for _{α n, θ + β n -sin} -1 {sin (θ-α n) / n}> 90 ° ·· (8-2) is a necessary condition.

Ideally, each condition should be satisfied at the same time,
Actually, some conditions may not be satisfied due to various restrictions such as the thickness of the Fresnel prism, the processing state or the molding state, and the size at which the Fresnel prism can be arranged. However, although most of the assumed light rays pass through the predetermined optical path of refraction reflection and refraction, the efficiency is lowered, but the purpose of changing the direction of flash light emission can be almost achieved.

FIG. 10 shows an example in which the above various conditions are satisfied. FIGS. 10A to 10C show ray traces when the directions of incident rays are changed with respect to the same Fresnel prism. In fact, the luminous flux incident on the Fresnel surface has a certain angular range distribution, and in FIG. 10, a 20 ° distribution of ± 10 ° is assumed based on the state where the optical panel 6 is inclined by 80 ° in the distribution area. Yes, the value of each parameter is as follows. θ ₁ = 80 °, θ ₂ = 70 °, θ ₃ = 90 ° α _n = 80 °, β _n = 50 ° n = 1.492 (Assuming acrylic resin) Applying these to the above conditional expressions, , a = 90 ° -50 ° = 40 ° b 1 = 80.0 °, b 2 = 63.3 °, b 3 = 96.7 ° c 1 = 50.0 °, c 2 = 56.7 °, c ₃ = 43.3 ° d ₁ = 0 °, d ₂ = -3.3 °, d ₃ = 3.3 ° Critical angle = 42.2 °, all of the above conditions (1) to (5) By filling and optimizing the pitch of the Fresnel prism, it becomes possible to change the direction of flash light emission without loss of light quantity.

In the above embodiments, attention was focused on the local prism surface of one Fresnel prism, but similar light control can be performed on each surface, and by optimizing the set angle of each surface, It is possible to precisely control the light distribution after the Fresnel prism is emitted.

FIG. 11 shows a second embodiment of the present invention. In order to simplify the description, the same parts as those in the first embodiment will be designated by the same reference numerals. In this embodiment, a reflector plate 7 provided in the upper portion of the camera body 1 is provided in front of the reflection shade 4 of the flash light emitting portion and in a front portion of the lid member 5 which is rotatably hinged to the upper portion of the camera body 1. The front reflection plate 21 facing up to the substantially central portion of the front part is arranged, and the optical panel 22 having the inner surface side as the fine prism surface 22a is connected between the front end of the reflection plate 21 and the front end of the reflection plate 7. Then, they are arranged integrally. The other structure is similar to that of the first embodiment.

In the present embodiment having the above-mentioned structure, the light emitted from the flash light emitting portion formed of the flash light emitting tube 3 and the reflecting shade 4 located inside the camera body 1 is reflected from the reflecting plate 7, the front reflecting plate 21 and the optical panel 22. The light is changed in direction and is emitted from the optical panel 22.

By the way, in the above-mentioned first embodiment, the optical panel 6 which is the final light emitting surface is large, and there is a component emitted from a portion close to the camera body 1, so that the effect against the red eye phenomenon is insufficient. In the embodiment, this point is improved. The light emitting portion is limited to the optical panel 22 located at the tip of the light redirecting member, and the reflection plate 21 is provided for the portion below the light redirecting member, so that the partial luminous flux is reduced. Is the front reflector 2
The light is incident on the optical panel 22 via 1 or via the front reflection plate 21 and the reflection plate 7, and the direction is converted by the total reflection within the panel 22 to head for the subject. With such a configuration, it becomes possible to efficiently change the irradiation direction of the flash light emission without causing the red-eye effect.

FIG. 12 shows a third embodiment of the present invention. In the figure, 31 is a camera body, 32 is a taking lens barrel, 33 is an external flash device, and inside thereof, a flash arc tube 34 and a reflection shade 35 are provided on one end face side, and a wide range is provided on the front surface thereof. An optical panel 36 having a fine Fresnel prism surface 36a formed on the inner surface and a flat surface 36b on the outer surface is provided. The reflection surface 35a side of the reflection shade 35 facing the optical panel 36 extends from the reflection surface 35b on the front side in alignment with the prism surface 36a of the optical panel 36.

In the present embodiment having the above-described structure, an illumination device similar to that of the first embodiment is built in an external flash device which is separate from the camera body, and the light ray traces emitted from the flash arc tube 34 are also the same. Is. However, the difference from the first embodiment described above is that one of the reflecting shades 35 and the reflecting plate 7 of the first embodiment is integrated by forming one of the reflecting shades 35 as the extending reflecting surface 35a. This is the point of composition. With this configuration, the number of parts can be reduced.

Further, in the conventional electronic flash device, in order to prevent the red-eye phenomenon, the position of the flash light emitting section had to be arranged in the upper part, but the flash light emitting tube 34 of the flash light emitting section should be arranged in the lower part. It is also possible to increase the degree of freedom in the layout of parts, and it has become possible to provide a flash device having an unprecedented form.

Further, since the entire front surface of the flash device can be used as the light emitting portion, the light can be efficiently collected and the light source can be a light source close to the surface light emission, so that the soft lighting is possible. Further, as shown in the drawing, since the Fresnel prism surface 36a is formed on the light emitting portion side of the optical panel 36 and the outer surface side is the flat surface 36b, even if the front surface of the optical panel 36 is dirty, it can be easily wiped. Therefore, it is possible to prevent dust from accumulating on the Fresnel prism portion and deterioration of optical characteristics as in the conventional case.

[0049]

As described above, according to the present invention as set forth in claim 1, the flash light emitting tube and the flash light emitting portion formed of the reflection shade for controlling the light emitting direction of the flash light emitting tube are opposed to each other in the irradiation direction of the flash light emitting portion. However, by arranging the optical panel on which at least a plurality of fine prism surfaces are formed on the side of the flash tube so as to be inclined with respect to the flash section, the emitted light from the arc tube has less light loss than before, and the efficiency is improved. It can collect light well, and since the light emitting part can be widened to make it a surface light source, it is possible to softly illuminate the subject, and it is easy to modify the fine light distribution and has a high degree of design freedom. Can be converted. Also,
According to the present invention as set forth in claim 2, by covering the opening other than the reflection shade and the optical panel with a reflection plate, light can be effectively condensed without further loss of light quantity. Further, according to the present invention as defined in claim 3, the arrangement of the flash light emitting portion and the shape of the optical panel satisfy a predetermined relational expression, so that no light amount loss occurs in the light emission of the flash light emitting portion.

According to a fourth aspect of the present invention, a flash light emitting portion comprising a flash light emitting tube and a reflecting shade for controlling the light emitting direction of the flash light emitting tube is built in the camera body, and the flash light emitting portion is at least in a photographable state. An optical panel that is positioned in a state of being inclined to the front surface of the flash panel and has a plurality of fine prism surfaces formed on at least the flash light emitting portion side, and a reflection configured to cover the flash light emitting portion and the opening other than the optical panel portion. By providing the illuminating device for photography having a light direction changing member composed of a plate, the flash light emitting portion can be arranged at any position such as the top surface or the side surface of the camera to prevent the red-eye phenomenon, and the tilt of the optical axis can be prevented. On the other hand, since the tolerance is high, the degree of freedom in arranging the parts in the camera is increased, and the configuration is easy. Further, according to the present invention as set forth in claim 5, the light direction changing member arranged on the front surface of the flash light emitting portion is rotatably supported and can be stored when the camera is carried, and the back surface is used as a camera protection member. By
Since it can also be used as the barrier portion of the lens barrel of the camera, space efficiency is improved.

The present invention as set forth in claim 6 is an optical system in which a flash light-emitting tube, a reflecting shade for controlling the light emitting direction of the flash light-emitting tube, and a plurality of fine prism surfaces are formed at least on the surface side receiving flash light. In addition to the effect of the invention as set forth in claim 1, the flash lighting tube is provided with a illuminating device for photography, which is composed of a flash light emitting section in which the panel is inclined with respect to the light emitting optical axis. Since the restriction on the position is relaxed, the degree of freedom in design regarding the component layout is increased, and the external flash device having the special surface emitting portion with good light collection efficiency can be obtained. Further, the present invention as set forth in claim 7 is a compact external flash device having a surface emitting portion with a good light-collecting efficiency by extending a part of the reflector to form a reflector for the prism surface of the optical panel. be able to.

[Brief description of drawings]

FIG. 1 is a side view of a camera having an illumination device for photography according to a first embodiment of the present invention in a use state.

FIG. 2 is likewise a side view in a stored state.

FIG. 3 is an exploded perspective view of the light emitting unit.

FIG. 4 is a ray trace diagram by a reflection shade of the flash light emitting portion.

FIG. 5 is a ray trace diagram in the vicinity of the optical panel.

FIG. 6 is a ray trace diagram of the entire light emitting unit.

FIG. 7 is an explanatory diagram of an angular relationship of the optical panel.

FIG. 8 is likewise an explanatory view of the optimum angle of incidence on the optical panel.

FIG. 9 is also an explanatory diagram of necessary constants for obtaining a relational expression of appropriate conditions.

FIG. 10 is a ray trace diagram in a state where the relational expression is satisfied, and in (a), (b), and (c), the angles formed by the luminous flux direction of the light source and the horizontal direction are 80 °, 70 °, and 9 °, respectively.
This is the case of 0 °.

FIG. 11 is a side view of the camera having the photographic illumination device according to the second embodiment of the present invention in use.

FIG. 12 is a side view of a camera having an illumination device for external photography according to a third embodiment of the present invention in use.

[Explanation of symbols]

1,31 ··· Camera body, 2,32 ··· Lens barrel, 3,3
4 ... Flash arc tube, 4, 35 ... Reflector, 5 ... Lid member, 6, 22, 36 ... Optical panel, 6a, 6b, 22
a, 36a ... Fresnel prism surface, 7 ... Reflector, 8
a, 8b ... Side reflector, 21 ... Reflector, 33 ... External flash device.

Claims (7)

[Claims] 1. A flash light emitting part comprising a flash light emitting tube and a reflection shade for regulating the light emitting direction of the flash light emitting tube, and a plurality of fine prisms facing the flashing light emitting part and facing at least the flash light emitting tube side. An illuminating device for photography, wherein an optical panel having a surface is arranged so as to be inclined with respect to the flash light emitting section. 2. The illumination device for photography according to claim 1, wherein openings other than the reflection shade and the optical panel are covered with a reflection plate. 3. The illuminating device for photography according to claim 1, wherein the arrangement of the flash light emitting portions and the shape of the optical panel satisfy the following relational expression. 0 ≦ α _n , β _n , θ ≦ 90 ° α _n + β _n −θ> 0 θ ≧ α _n , θ + β _n > 90 ° θ <α _n , θ + β _n −sin ⁻¹ {sin (θ− α
_n ) / n}> 90 °, where θ is the angle between the light beam direction of the light source and the horizontal direction, α _{n is} the inclination of the n-th Fresnel prism entrance surface, and β _{n is} the inclination of the n-th Fresnel prism total reflection surface. , N: Refractive index of the material of the optical panel. 4. A flash light emitting part comprising a flash light emitting tube and a reflecting shade for controlling the light emitting direction of the flash light emitting tube is built into the camera body, and is positioned in a state inclining to the front surface of the flash light emitting part at least in a photographable state. A light redirecting member including an optical panel having a plurality of fine prism surfaces formed on at least the flash light emitting portion side, and a reflecting plate configured to cover the flash light emitting portion and an opening other than the optical panel portion. A camera provided with a lighting device for photography having: 5. The light direction changing member arranged on the front surface of the flash light emitting portion is rotatably supported and can be stored when the camera is carried, and the back surface is used as a camera protection member. The camera according to claim 4. 6. An optical panel in which a flash light emitting tube, a reflector for controlling the light emitting direction of the flash light emitting tube, and a plurality of fine prism surfaces formed on at least the surface receiving flash light are tilted with respect to the light emitting optical axis. A illuminating device for photography, which can be attached to a camera, characterized in that the illuminating device is composed of a flash light emitting section arranged as described above. 7. The camera-mountable photographic lighting according to claim 6, wherein a part of the surface of the reflection shade is extended so as to face the prism surface of the optical panel to form a reflection plate. apparatus.