JPH0553177A - Auxiliary illuminating device for camera - Google Patents

Abstract

PURPOSE:To make an auxiliary illuminating device which emits light to an object in order to prevent the red-eye effect of the object at the time of flash photographing, for example, compact, and also to obtain good orienting characteristics. CONSTITUTION:The auxiliary illuminating device is used in a photographing device in which photographing is executed by making use of a flash illuminating device, and prevents the red-eye phenomenon by preliminarily illuminating the object for a specified time prior to the photographing by flash illuminating; it has a light emitting means constituted of a light emitting part 2, an electrode 3, and a sealing member 4 sealing the light emitting part 2, a reflecting member 5 reflecting the light from the light emitting means, and a projecting optical element 1 for projecting light to the object by receiving direct light from the light emitting part 2 and reflected light by the reflecting member 5; and it satisfies conditions below. 0.5<=1/d<=0.9. Provided that (d) is the effective diameter of the projecting optical element 1, 1 is a distance from a virtual image position by the projecting optical element on the center of the light emitting part to the projecting surface of the projecting optical element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash device for illumination used in a photographing device such as a camera or a camera having the flash device. More specifically, the present invention relates to an auxiliary lighting device for preventing or mitigating a so-called red-eye phenomenon that occurs when photographing with the flash device.

[0002]

2. Description of the Related Art In a photographing device such as a camera, an illumination device that emits a flash light such as a strobe is widely used when the subject brightness is low. When a device for illuminating a subject is used for such an instant shooting, a so-called red-eye phenomenon may occur in which the eyes of humans or animals are shot red.

The red-eye phenomenon occurs when the retina is illuminated by a strong flash of light through a wide-open pupil in a dark environment, and reflected light containing a large amount of the red wavelength is photographed. Therefore, the direction of incidence of light from the flash device to the eye tends to be stronger as the shooting optical axis becomes closer to parallel, and especially in a camera with a built-in strobe, the distance from the shooting optical axis to the strobe cannot be very large. Red-eye phenomenon is likely to occur.

In order to prevent or mitigate the red-eye phenomenon, a method of performing preliminary illumination prior to the flash illumination at the time of photographing is based on the idea that a wide open pupil should be narrowed down just before photographing. It is considered.

As one of the methods, a lamp for performing preliminary light emission is separately provided on a part of a camera or a strobe,
Some illuminate a subject for a certain period of time before shooting. On the other hand, as another method, there is known a method in which a strobo light is preliminarily emitted in a pulsed form several times before the main light emission at the time of photographing. Furthermore, as another method, there is known a method in which a lamp for performing preliminary light emission is provided inside a reflecting umbrella of a strobe.

[0006]

[Problems to be Solved by the Invention] Each of the methods for alleviating the red eye phenomenon described above has its own problems as well as its features.

That is, in the first method, a large lamp and a large amount of electric power for causing the lamp to emit light are required to obtain a sufficient effect, and it is very difficult to incorporate the lamp into a camera.

The second method does not require a separate lighting device for preliminary light emission and is advantageous in terms of space, but requires an electric control circuit and a capacitor for performing preliminary light emission. Depending on the control method, the amount of light at the time of main light emission, that is, the guide number may decrease due to the preliminary light emission.

Furthermore, according to the third method, since the strobe reflector and Fresnel can be used as they are to project light onto a subject, there is no need to provide a special optical system.
It is possible to direct the light from the lamp to the subject with some efficiency, but this method is effective in that the effect of inserting the preliminary flashing lamp inside the reflector of the flash is negligible. Only when the umbrella or Fresnel is large enough, it is difficult to incorporate it into a normal camera like the first method.

[0010]

In order to solve the above problems, the present invention is used in a photographing apparatus capable of photographing using a flash illumination device, and a subject is fixed before photographing by flash illumination. An auxiliary lighting device for pre-illuminating for a time to prevent a red-eye effect, comprising: a light emitting unit, an electrode, and a light emitting unit including a sealing member for sealing the light emitting unit; and a reflecting member for reflecting light from the light emitting unit. A light projecting optical element is provided for receiving the direct light from the light emitting section and the reflected light from the reflecting member and projecting the light onto an object, and is configured to satisfy the following conditions.

0.5 ≦ l / d ≦ 0.9 (1) where d is the effective diameter of the light projecting optical element, and l is the virtual image position of the light projecting optical element at the center of the light emitting portion It is the distance to the exit surface.

Generally, in the auxiliary illuminating device having the above-mentioned structure, the spread radiated mainly by the light directly entering the light projecting optical element from the light emitting portion is determined, and after being reflected by the reflecting member, enters the light projecting lens, for example. It can be said that the brightness of light determines the overall brightness. That is, it can be said that the irradiation range is determined by the effective diameter of the light projecting lens of the light emitting unit and the position of the light emitting unit, and the light collecting efficiency is determined by the shape of the reflector.

Therefore, in the formula (1), if l / d exceeds the upper limit, the irradiation range becomes narrow, and it is not possible to deal with the wide-angle side photographing lens. Also, the total length of the auxiliary lighting device has increased,
The reflector becomes large and it becomes difficult to incorporate it in a camera or strobe.

Further, in the equation (1), if l / d is below the lower limit, the irradiation range is expanded more than necessary, and it becomes difficult to optimize the shape of the reflector for increasing the light collection efficiency. Even if the optimization can be performed, d becomes considerably large, and the size of the entire apparatus becomes large, which becomes an obstacle when incorporated in a camera or a strobe.

[0015]

1 is a sectional view of an auxiliary lighting device according to a first embodiment of the present invention. In the figure, 1 is a light emitting element including a light emitting portion 2 such as a filament, an electrode 3, and a sealing member 4, 5 is a reflecting member having a reflecting surface 6, and 7 is an optical element for projecting light. However, in this embodiment, the optical element 7 is a parallel plate having no power, and is formed of a part of the exterior member of the camera or strobe or is integrated with the exterior member. Further, as the reflection member 5, a thin metal plate is preferably formed into a desired shape by pressing, or a resin such as a plastic is formed into a desired shape, and then a metal substance is vapor-deposited on the anti-slope 6 is preferably used. . In this embodiment, the reflecting member 5 is a cone surface. FIG. 2 shows numerical values relating to a specific shape in the present embodiment when the inclination of the generatrix of the cone surface of the reflecting member is θ = 25 °, the thickness t of the optical element is t = 1.5, and the effective diameter d of the optical element is d = 5.5. The cross section of the illuminance distribution of the illumination light at a position 3 m away from the final surface 8 of the optical element is shown by the relative ratio on the vertical axis and the irradiation range on the horizontal axis. 35mm on the horizontal axis
The view angle range for each focal length of the taking lens corresponding to the lateral direction of the film is also shown. In the figure, broken line 9 and solid line 1
0 and the chain double-dashed line 11 respectively indicate the distance l ′ from the center of the light source to the first surface of the optical element 7 to be 2.43, 2.63, 2.93.
It shows the change of the illuminance distribution when it is changed. Which value is adopted as l'is determined according to the focal length of the photographic lens to be applied. If the shooting lens is a replaceable zoom lens or a zoom lens with a variable focal length, move the light emitting element along the optical axis according to the focal length of the shooting lens to be mounted to balance the illumination range and illuminance. It is advisable to make the variable. Further, when the strobe used is a zoom strobe with a variable irradiation angle, the balance may be variable according to the irradiation angle of the strobe. In addition to moving the light emitting element, the same effect can be obtained by moving the reflector or moving the light emitting element and the reflector integrally.

In the present embodiment, the relationship between l'and l in the equation (1) is l = l '+ t / n (2), where n is the refractive index of the optical element 7, and therefore the projection lens 7 is used. When n = 1.491 is substituted with acrylic as the material of, the value of the equation (1) becomes l / d = 0.62 to 0.72.

As for the definition of the center of the light source, for a light emitting portion having a substantially uniform brightness like a filament,
The position of the center of gravity of the geometrical shape may be used. Further, for a discharge tube having a non-uniform luminance distribution, it is appropriate to use the center of gravity of the luminance distribution. Further optical element 7
The effective diameter of is uniquely determined when the optical element is circular, but when the optical element is not circular, it indicates the diameter of the smallest circle including the optical element.

FIG. 3 is a diagram showing a second embodiment of the present invention. In this embodiment, the reflecting member 12 is composed of a spherical surface portion 13 and a cylindrical surface portion 14, and a light projecting lens 15 for projecting light.
Is composed of a biconvex lens. The specific numerical values regarding the shape of the present embodiment are as follows.

Distance of the light source center from the first surface of the projection lens 1 '= 2.04 Distance of the reflecting member from the first surface of the projection lens L = 3.1 Radius of curvature of the reflecting member = 3.75 Radius of curvature of the first surface of the lens r ₁ = 11.5 Radius of curvature of the final lens surface of the projection lens r ₂ = -15.3 Thickness of projection lens t = 1.84 Diameter of projection lens d = 6 .6

FIG. 4 shows the illuminance distribution of this embodiment as in FIG. However, the scale of the vertical axis is reduced to about 1 / 1.7 times that of FIG. That is, the illuminance near the center is increased by about 1.7 times, and the effect of the converging action of the reflector and the light projecting lens is exhibited as compared with the first embodiment of FIG.

Also in this embodiment, if the refractive index n of the light projecting lens 15 is n = 1.491, the distance l from the final lens surface of the light projecting lens 15 to the virtual image of the light source center by the light projecting lens 15 is l. = 3.90, the value of equation (1) is l / d = 0.59. As can be seen from these values, in the present embodiment, the center of the light source is brought as close as possible to the light projecting lens to achieve miniaturization, and the power of the light projecting lens is used to suppress the unnecessary expansion of the illumination range caused thereby. The spherical surface enhances the light collecting effect.

In the present embodiment, the cylindrical portion 14 of the reflecting member 12 is a portion provided because the spherical portion 13 of the reflecting member 12 cannot be extended due to the restriction of the diameter of the light projecting lens 15, and serves as a reflecting member. It cannot be said that it efficiently plays the role of collecting light. Therefore, it is possible to configure the surface of the cylindrical portion as a diffusing surface so that the incident light is effectively incident on the light projecting lens.

FIG. 5 is a diagram showing a third embodiment of the present invention. In the present embodiment, the shape of the reflecting member 16 is a rotary suiface. The numerical values related to the specific shape are as follows.

Distance of the light source center from the first surface of the light projecting lens 1 '= 2.85 Distance of the reflecting member from the first surface of the light projecting lens L = 3.38 Radius of curvature r of the first surface of the light projecting lens ₁ = 8.7 Radius of curvature of second surface of light projecting lens r ₂ = -16.3 Thickness of light projecting lens t = 1.99 Diameter of light projecting lens d = 6.6 Shape of reflecting member 16

[0025]

[Outer 1] In, R = 2.0466 k = -0.9599. However, X is a coordinate in the horizontal direction with the vertex of the reflecting member 16 as the origin, and h is a coordinate in the vertical direction. Therefore, the value of the equation (1) is 1 / d = 0.84.

FIG. 6 shows the illuminance distribution, and the scale on the vertical axis is reduced to about 1 / 1.5 times that of FIG. In the present embodiment, l is set to be long and the reflecting member is formed into a rotary ovum surface to limit light spreading to the periphery and improve the efficiency of condensing light to the center.

Although the light projecting lens having power is used in the second and third embodiments, the light incident on the edge area of the light projecting lens is not projected forward, resulting in a loss of light quantity. Therefore, it is desirable that the first surface of the light projecting lens is a convex surface with respect to the light emitting portion and is deflected inward to reduce the light incident on the edge region. On the other hand, it is effective that the second surface of the light projecting lens has a convex surface facing the object to be illuminated in the sense of condensing light, but it may be a concave surface or a flat surface depending on the desired illumination range. is there. Also in the second and third embodiments, as in the first embodiment, it is possible to change the balance between the illuminated range and the illuminance by moving the light emitting element and the reflector along the optical axis. ..

[0028]

As described in the above description of the embodiments, according to the present invention, in the illumination system for alleviating the red-eye effect,
The optimal balance of overall length and diameter is realized, and it is possible to achieve both miniaturization and improvement of light collection efficiency. Therefore, it can be easily incorporated into a camera or strobe, and the red-eye effect can be effectively mitigated.

[Brief description of drawings]

FIG. 1 is a sectional view of an auxiliary lighting device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing irradiation characteristics of the lighting device shown in FIG.

FIG. 3 is a sectional view of an auxiliary lighting device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing irradiation characteristics of the illumination device shown in FIG.

FIG. 5 is a sectional view of an auxiliary lighting device according to a third embodiment of the present invention.

6 is a diagram showing irradiation characteristics of the irradiation device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Filament 3 Electrode 4 Sealing member 5, 12, 16 Reflector 7, 15 Projector lens

Claims (8)

[Claims] 1. An auxiliary lighting device for use in a photographing device capable of photographing using a flash lighting device, for pre-illuminating a subject for a certain period of time prior to shooting by flash lighting to prevent the red-eye effect. A light emitting unit, an electrode, and a light emitting unit including a sealing member that seals the light emitting unit, a reflecting member that reflects light from the light emitting unit, direct light from the light emitting unit, and reflected light from the reflecting member are received by a subject. An auxiliary lighting device for a camera, which has a projection optical element for projecting light and satisfies the following conditions. 0.5 ≦ l / d ≦ 0.9 where d is the effective diameter of the light projecting optical element, l is the distance from the virtual image position of the light projecting optical element at the center of the light emitting portion to the exit surface of the light projecting optical element Is. 2. The auxiliary lighting device according to claim 1, wherein the projection optical element is formed of a part of an exterior member of a camera or a strobe or is integrated with the exterior member. 3. The auxiliary lighting device according to claim 1, wherein the projection optical element is a parallel plate having no optical power. 4. The auxiliary lighting device according to claim 1, wherein a surface of the light projecting optical element facing the light emitting portion has a convex surface facing the light emitting portion. 5. The auxiliary lighting device according to claim 1, wherein a part of the reflecting surface of the reflecting member is a light diffusing surface. 6. The light emitting means moves on the optical axis of the auxiliary lighting device according to the focal length of a shooting lens mounted on the shooting device, the irradiation range of the flash lighting device, or changes in them. The auxiliary lighting device according to claim 1. 7. The reflecting member moves on the optical axis of the auxiliary lighting device according to the focal length of the photographing lens mounted on the photographing device, the irradiation range of the flash lighting device, or changes thereof. The auxiliary lighting device according to claim 1. 8. The auxiliary lighting device according to claim 6 or 7, wherein the light emitting means and the reflecting member move integrally.