JP4280380B2 - Light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light emitting device.
[0002]
[Prior art]
Conventionally, some still cameras can be equipped with a detachable light emitting device (commonly referred to as a strobe) or have a built-in one. Furthermore, some light emitting devices have an optical member mounted on the front surface, and proposals have been made to convert the irradiation characteristics, such as changing the color temperature of the emitted light or changing the irradiation direction. For example, Japanese Patent Application Laid-Open No. 8-201886 discloses a technique for changing the color temperature of emitted light, which is approximately the same size as the exit opening of the reflective shade in front of the light emitting device composed of the reflective shade and the discharge tube. A transmissive color liquid crystal is arranged, and the transmissive color liquid crystal is provided with a complementary primary color filter, and the overall color temperature is controlled by controlling the transmittance of pixels corresponding to each color. . Further, when not in use, the transmissive color liquid crystal is stored in a retreat space provided above the light emitting device by a drive mechanism using a motor and a gear.
[0003]
Also, except for cameras equipped with close-up light-emitting devices, ordinary cameras are arranged with a certain distance or built-in optical axis of the light-emitting device with respect to the optical axis of the taking lens in order to suppress the red-eye phenomenon. ing. When such a camera is used for strobe photography at a short distance, a deviation occurs between the illumination range of the strobe light and the photography range, resulting in uneven illumination on the subject.
[0004]
In order to solve the problem of uneven illumination, a light emitting device in which a diffusion plate is taken in and out of the front surface of the light emitting unit has been proposed. For example, in Japanese Patent Laid-Open No. 59-210426, a Fresnel prism is fixed to a camera body, and a light emitting device is disposed behind the Fresnel prism so as to be movable up and down. During normal shooting, the light emitting device is raised to emit light without passing through the Fresnel prism, and when the close-up mode is switched, the close-up lens moves to the front of the photographing lens and at the same time the light emitting device is lowered by the drive mechanism. Therefore, the emitted light is bent toward the optical axis of the photographing lens by the Fresnel prism. Since the emitted light is bent, the photographing range and the illumination range are substantially matched, and uniform illumination without illumination unevenness can be obtained.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional example, in the case of the configuration of Japanese Patent Application Laid-Open No. 8-201886, when the transmissive color liquid crystal is not used, a space for retreating the transmissive color liquid crystal is required, and the light emitting device and the camera are enlarged. In addition, since the amount of movement during retraction is large, the drive mechanism is complicated and large.
[0006]
Further, in the configuration of Japanese Patent Laid-Open No. 59-210426, it is necessary to move the entire light emitting device beyond the size of the Fresnel prism, so that both the mass and the movement amount are increased, and the drive mechanism is increased in size and complexity. Invite you to go back to the demand for smaller cameras.
[0007]
Furthermore, in any known technique, the emission aperture of the light emitting device and the transmissive color liquid crystal or Fresnel prism must be moved relative to the size of the emission aperture, and the amount of movement is necessarily large. turn into. If the height of the injection opening is 10 mm, it is necessary to move at least 12 to 13 mm.
[0008]
As described above, since the conventional light emitting device cannot be increased in size, it has been impossible to reduce the size of the camera, or to mount or incorporate the light emitting device having the above-described function in a small camera. .
[0009]
In view of the circumstances described above, the present invention provides a light emitting device that can be used in a small camera or a small camera while including an irradiation characteristic conversion member that performs conversion of color temperature of emitted light, conversion of irradiation direction, and the like. It is intended to provide.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a light source, an optical member that irradiates light from the light source in a predetermined direction, and characteristics of light emitted from the optical member. in the light-emitting device having the emission characteristic conversion member for converting the optical member, closely a region where the irradiation light becomes sparse on a plane perpendicular to and the light emitted axis in front of the space of the optical member A plurality of cylindrical surfaces that are alternately formed, and the irradiation characteristic conversion member is disposed in front of the cylindrical lens, and includes slits having the same pitch as the cylindrical lens, and the irradiation characteristic. In the light emitting device, the amount of movement in the pitch direction when the conversion member is not used and when used is ½ of the pitch .
[0011]
According to this configuration, the light emitted from the cylindrical lens is alternately formed with a region where the irradiation light is sparse and a region where the irradiation light is sparse on a surface orthogonal to the optical axis at a predetermined distance from the front surface. By moving the irradiation characteristic conversion member so that one of the sparse or dense regions is selected, the irradiation characteristic can be converted with a simple configuration. Therefore, it is possible to reduce the size of the light-emitting device, and to contribute to mounting on an ultra-compact compact camera or miniaturization of the camera.
[0016]
A specific configuration for realizing the object of the present invention is characterized in that, as described in claim 2 , the irradiation characteristic conversion member has a function of converting a spectral characteristic of light emitted from the light source. To the light emitting device.
[0017]
According to this configuration, it is possible to perform color temperature conversion and color correction of illumination light by using the filter member that converts the spectral characteristics of the emitted light emitted from the light source.
[0018]
According to a specific configuration for realizing the object of the invention according to the present application, as set forth in claim 3 , the irradiation characteristic conversion member has a function of attenuating the intensity of the irradiation light. It is in.
[0019]
According to this configuration, the function of attenuating the intensity of the illumination light makes it possible to moderately reduce the intensity of the illumination light in short-distance shooting, and an optimal shooting result can be obtained.
[0020]
A specific configuration for realizing the object of the present invention is characterized in that, as described in claim 4 , the irradiation characteristic conversion member is an optical member having a characteristic of bending an optical path of the irradiation light. In the light emitting device.
[0021]
According to this configuration, by using an optical member having the characteristic of bending the optical path of illumination light, the irradiation direction can be switched, and illumination unevenness in short-distance shooting can be prevented, or based on focal length information The irradiation angle can be switched.
[0022]
A specific configuration for realizing the object of the invention according to the present application is the light emitting device according to claim 5 , wherein the optical member is a plurality of prisms arranged at predetermined intervals. There is .
[0023]
According to these configurations, the optical path of the illumination light can be bent with a simple configuration, and the size and weight can be reduced.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 is an exploded perspective view showing a light emitting device of the present invention. FIG. 2 shows a cross-sectional view in a plane parallel to the optical axis.
[0025]
In each figure, reference numeral 1 denotes a prism member, which controls the progress of light emitted by a discharge tube 4 as a light source. Reference numeral 2 denotes a filter member as an irradiation characteristic conversion member, which is disposed on the front surface of the prism member 1. The irradiation characteristic conversion member 2 has a color temperature conversion (LB) or color correction (CC) filter or the like to reproduce an appropriate color according to the subject, illumination light, and film used during flash photography. It is possible to use a neutral density (ND) filter or the like that moderately reduces the intensity of illumination light at a shooting distance, particularly at a short distance. A window member 3 is made of transparent glass or resin, and is fixed to the camera body or the casing of the light emitting device. Reference numeral 4 denotes a discharge tube (light-emitting tube) disposed at the rear portion of the prism member 1 and instantaneously emits a large amount of light using a control circuit and a battery (not shown). A reflecting plate 5 has a semi-cylindrical shape substantially in contact with the outer periphery of the discharge tube 4 and is provided at the back of the discharge tube 4 to reflect light from the discharge tube 4 toward the prism member 1.
[0026]
The prism member 1 is processed using transparent glass or resin, and a cylindrical convex lens 7 is formed on the back surface so as to face the discharge tube 4, and the side walls 6 a, sandwiching the convex lens 7 and the discharge tube 4 are sandwiched. 6b is formed, and curved surfaces 8a and 8b serving as outer surfaces are formed in communication with the side walls 6a and 6b. In addition, a plurality of cylindrical lenses 9 are formed in the lateral direction on the front surface. Slits 2 a having the same pitch as that of the cylindrical lens 9 are provided in the filter member 2.
[0027]
3A and 3B are explanatory views showing the state of the light emitting device when the filter member 2 is not used and when it is used. FIG. 3A shows the state when the filter member is not used, and FIG. 3B shows the state when the filter member is used. Shows the state. As described above, when the filter member 2 is not used, the slit 2 a is positioned in front of the cylindrical lens 9 and is not interposed in the light from the prism member 1, and when the filter member 2 is used, the slit 2 a is positioned in the middle of the cylindrical lens 9. Then, the light from the prism member 1 is transmitted. In order to form two states in this way, the movement amount when the filter member 2 is not used and when it is used is set to ½ of the pitch of the cylindrical lens 9.
[0028]
Next, how the light rays emitted from the discharge tube 4 pass through the prism member 3 will be described with reference to FIG. In the present embodiment, an acrylic resin is used for the prism member 1 and the refractive index is set to about 1.49.
[0029]
The light beam from the discharge tube 4 enters the convex lens 7 and the flat surfaces 6a and 6b of the prism member 1. Since the convex lens 7 is not a simple cylindrical surface but a curved surface, the light incident on the convex lens 7 is refracted and becomes parallel and travels in the prism member 1. Further, since the curved surfaces 8a and 8b are also configured so that the reflected light is collimated, the light incident on the planes 6a and 6b is refracted and reaches the curved surfaces 8a and 8b. Reflected and collimated. Thus, since the light beam from the discharge tube 4 is once refracted by the flat surfaces 6a and 6b and then reflected by the curved surfaces 8a and 8b, the entire optical system can be miniaturized.
[0030]
The light beam collimated by the convex lens 7 and the side walls 6a and 6b and the curved surfaces 8a and 8b reaches the cylindrical lens 9 provided on the front surface. The curved surface of the cylindrical lens 9 is not a simple cylindrical surface, but is a curved surface optimized for minimizing the influence of aberration. Therefore, when the focal point is formed by the cylindrical lens 9, the focal point is set at approximately one linear position. Then, a plurality of focal points are formed in a space at a certain distance from the lens surface. After the focal points are formed, the object side is irradiated with a predetermined angle. As described above, in the space on the exit surface side of the prism member 1, on the surface P intersecting with the irradiation direction A in the figure, the light beam is focused by the prism member 1, the region 100 is dense, and the light beam is almost all. A sparse area 101 that does not pass through is created.
[0031]
On the other hand, the light beam emitted backward from the discharge tube 4 is reflected by the reflecting plate 5, passes through the discharge tube again, enters the prism member 1, and enters the convex lens 7 and the side walls 6a and 6b as described above. To do.
[0032]
Next, focus formation in each state of the filter member 2 shown in FIG. In FIG. 3A, the filter member 2 is retracted to a position (sparse region 101) through which almost no light beam passes. Therefore, the light beam emitted from the prism member 1 passes through the slits 2 a of the filter member 2 as it is and is irradiated to the subject without being affected by the filter member 2. On the other hand, when the filter member 2 is used, the filter member 2 is moved near the focal point (the dense region 100). As a result, as shown in FIG. 3B, the subject is irradiated with the irradiation light whose irradiation characteristics are converted by the filter member 2.
[0033]
In the above description, the illumination angle is fixed and the light emitting device has a constant illumination angle. However, the present invention can also be applied to an illumination angle variable type light emitting device mounted on a zoom camera or the like. Hereinafter, description will be given with reference to the drawings.
[0034]
FIG. 4 is a side cross-sectional view showing a light emitting device of variable irradiation angle type as a modification of the first embodiment. 4 differs from the above embodiment in that a cylindrical lens 11 is provided on the surface of the window member 10 facing the prism member 1. The cylindrical lens 11 has a structure in which the cylindrical lens 9 is inverted. In the light emitting device of FIG. 4, the window member 10 is in a wide (wide angle) state at the position of a solid line, and is in a tele (telephoto) state at the position of a two-dot chain line.
[0035]
FIG. 5 shows the irradiation angle change state when the filter is not used in the irradiation angle variable type light emitting device of FIG. 4, where (a) is a wide state and (b) is a tele state. As shown in FIG. 5A, in the wide state, the lens surface vertex of the cylindrical lens 11 is set so as to be positioned in the vicinity of the focal point of the light beam emitted from the prism member 1. Thereby, the light beam incident on the window member 10 is controlled by the prism member 1 and is irradiated to the subject side while maintaining the irradiation angle. In the tele state, by positioning the vertex of the lens surface of the cylindrical lens 11 at a distance farther than the focal position, the light incident on the window member 10 is refracted by the lens and the irradiation angle is narrowed.
[0036]
In FIG. 5, only the wide and tele positions of the window member 10 are shown, but the irradiation angle is irradiated with an intermediate spread at the intermediate position. Although FIG. 5 shows only when the filter is not used, the light emitted from the prism member 1 is filtered between the dense region (100) and the sparse region (101) regardless of the wide or telephoto state. It is possible to convert the irradiation characteristics by moving the member 2.
[0037]
As described above, the amount of movement when the filter member 2 is not used and when it is used may be half the pitch of the cylindrical lens 9, so that a configuration with a minute amount of movement can be achieved. In this embodiment, if the height of the exit opening of the prism member 1 is 10 mm, the cylindrical lens 9 has seven structures, so that 10/7/2 = 0.714 mm is sufficient. Therefore, the space for saving when the filter member 2 is not used may be a small space. In addition, since the mechanism for driving the filter member 2 can be downsized and simplified, the light emitting device and the camera can be downsized. In other words, functions that could only be applied to a large camera with a built-in strobe can be applied to an ultra-compact compact camera.
[0038]
(Second Embodiment)
Next, a second embodiment of the light emitting device of the present invention will be described. In the second embodiment, since the photographing lens optical axis and the strobe optical axis are separated from each other, the irradiation direction is set based on the photographing distance information in order to prevent uneven illumination when photographing at a short distance. It can be switched.
[0039]
FIG. 6 is a side sectional view showing the configuration of the second embodiment of the light emitting device of the present invention. The configuration of FIG. 6 is different from the first embodiment in that the filter member 2 is changed to the prism plate 12. Other configurations are the same as those of the first embodiment. Here, the prism plate 12 functions as an irradiation characteristic conversion member. In the prism plate 12, a prism 13 is disposed at a position corresponding to the cylindrical lens 9 of the prism member 1, and a slit 14 is formed between the prisms 13.
[0040]
FIGS. 7A and 7B show the irradiation direction switching state in the second embodiment. FIG. 7A shows normal shooting and FIG. 7B shows short-distance shooting. As shown in FIG. 7A, during normal photographing, each of the prisms 13 is at an intermediate position of the cylindrical lens 9, and the emitted light is retracted in a sparse area 101. Therefore, the irradiation light is irradiated in the direction controlled by the prism member 1 without being affected by the prism 13. Further, at the time of short-distance photographing, each of the prisms 13 is in front of the cylindrical lens 9, and the emitted light is located in the dense region 100. The light beam emitted from the prism member 1 is refracted by each of the prisms 13 and bent downward in the figure (photographing lens optical axis side). Therefore, it is possible to prevent illumination unevenness even during close-up shooting. Also in the present embodiment, the amount of movement of the prism plate 12 is very small, so that the save space can be reduced. In addition, the drive mechanism can be reduced in size and simplified.
[0041]
In the second embodiment, the irradiation direction is switched at the time of short-distance shooting. However, by making the prism 13 a convex or concave cylindrical lens, the irradiation angle is set based on the focal length information of the shooting lens. It is also possible to switch the irradiation angle such as narrowing or widening.
[0042]
[Correspondence between Invention and Embodiment]
In the above embodiment, the prism member 1, the cylindrical lenses 9, 11 and the prism 13 correspond to an optical member, and the filter member 2 corresponds to an irradiation characteristic conversion member. The convex lens 7 corresponds to the first surface, the side walls 6a and 6b correspond to the second surface, and the curved surfaces 8a and 8b correspond to the third surface.
[0043]
【The invention's effect】
As explained above, the present invention shown in Claim 1, the optical member is closely and a region where the irradiation light becomes sparse on a plane perpendicular to and emitted light axis in front of the space of the optical member comprising an emission surface made of a cylindrical lens that forms alternating with areas comprising said illumination characteristic conversion member is disposed in front of said cylindrical lens comprises a slit by the cylindrical lens and the same pitch, the irradiation characteristic conversion member Because the amount of movement in the pitch direction when not in use and when used is ½ the pitch , the light emitting device can be miniaturized and mounted on an ultra-compact compact camera. Or it can contribute to size reduction of a camera.
[0046]
According to the second aspect of the present invention, since the irradiation characteristic conversion member has a function of converting the spectral characteristic of the light emitted from the light source, the color temperature conversion and color correction of the illumination light can be performed with a simple configuration.
[0047]
According to the third aspect of the present invention, since the irradiation characteristic conversion member has a function of attenuating the intensity of the irradiation light, it is possible to moderately reduce the intensity of the illumination light in short-distance shooting, and an optimal shooting result. Can be obtained.
[0048]
Since the present invention described in claim 4 is an irradiation characteristic conversion member using an optical member having a characteristic of bending the optical path of the irradiation light, the irradiation direction is switched, and it becomes possible to prevent uneven illumination in short-distance shooting. Alternatively, the irradiation angle can be switched based on the focal length information.
[0049]
According to the fifth aspect of the present invention, since the optical member includes a plurality of prisms arranged at predetermined intervals, the optical path of the illumination light can be bent with a simple configuration.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a light emitting device of the present invention.
2 is a cross-sectional view of the light emitting device of FIG. 1 in a plane parallel to the optical axis.
3 is an explanatory view showing a state of the light emitting device when the filter member shown in FIG. 2 is not used and when it is used.
FIG. 4 is a side sectional view showing a configuration in which the first embodiment of the present invention is a variable irradiation angle type.
5 is an explanatory view showing a state of irradiation angle change when the filter is not used in the variable irradiation angle light-emitting device of FIG. 4;
FIG. 6 is a side sectional view showing a configuration of a second embodiment of a light emitting device of the present invention.
FIG. 7 is an explanatory diagram showing an irradiation direction switching state in the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Prism member 2 Filter member 2a, 14 Slit 3 Window member 4 Discharge tube 6a, 6b Side wall 7 Convex lens 8a, 8b Curved surface 9, 11 Cylindrical lens 12 Prism plate 13 Prism 100 Dense area 101 Sparse area

Claims (5)

In a light emitting device including a light source, an optical member that irradiates light from the light source in a predetermined direction, and an irradiation characteristic conversion member that converts characteristics of the light emitted from the optical member,
Wherein the optical member comprises a cylindrical lens plurality alternately forming the front of the space and the exit region is irradiation light becomes a region closely consisting sparsely on a plane perpendicular to the optical axis of the optical member The irradiation characteristic conversion member is provided in front of the cylindrical lens, and includes slits having the same pitch as the cylindrical lens, and the pitch direction when the irradiation characteristic conversion member is not used and when used. The amount of movement of the light emitting device is set to ½ of the pitch .   The light emitting device according to claim 1, wherein the irradiation characteristic conversion member has a function of converting a spectral characteristic of light emitted from the light source.   The light emitting device according to claim 1, wherein the irradiation characteristic conversion member has a function of attenuating the intensity of the irradiation light. 2. The light emitting device according to claim 1, wherein the irradiation characteristic conversion member is an optical member for irradiation characteristic conversion having a characteristic of bending an optical path of the irradiation light. 5. The light emitting device according to claim 4, wherein the irradiation characteristic converting optical member is a plurality of prisms arranged at predetermined intervals.

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