JP4764088B2 - Imaging device - Google Patents

Description

The present invention relates to an imaging apparatus having a light emitting unit that uses a light emitting body such as a light emitting diode as a light source.

  Many illumination devices using a plurality of light-emitting diodes as light sources have been proposed as illumination devices used in imaging devices such as cameras.

  One of them is one in which each light emitting diode element itself has a light collecting function. In this method, a light emitting diode chip is fixed in a metal cup serving as a reflecting mirror, the front surface thereof is covered with a dome-shaped transparent resin, and the transparent resin has the function of a condenser lens. By appropriately selecting the diameter and curvature of the transparent resin portion of such a light emitting diode element, it is possible to obtain predetermined light distribution characteristics (see, for example, Patent Document 1).

  On the other hand, there has also been proposed an optical system configured such that a light-emitting diode itself as a light source does not have a condensing function, and a light beam emitted from the light source is condensed by a convex lens disposed in front of the light-emitting diode (for example, Patent Literature 2).

Furthermore, an optical system including a reflector that reflects a light beam emitted from the light source forward without providing a light collecting diode as a light source has been proposed (for example, see Patent Document 3).

JP 2002-148686A (paragraphs 0020-0022, FIGS. 1-3, etc.) JP 2000-89318 A (paragraphs 0005 to 0007, FIGS. 1 to 3 etc.) JP 2004-226509 A (paragraphs 0020 to 0028, FIGS. 1 to 5 and the like)

  A light emitting diode generates a large amount of heat simultaneously with light emission. For this reason, the light emitting diodes cannot be arranged so close to each other. Therefore, it is difficult to treat a plurality of light sources as if they are close to each other. Under such constraints, it is important how efficiently light from a plurality of light sources can be used and converted into illumination light having an irradiation range corresponding to the shooting angle of view (hereinafter referred to as a required irradiation range). .

  Also, generally used white light emitting diodes include a light emitting diode chip that emits blue light and a mold in which a phosphor that absorbs part of the blue light and generates long wavelength light is dispersed. It is comprised using resin. Then, white light is emitted by mixing the light emitted from the light emitting diode chip and the light generated from the phosphor. At this time, the central portion of the emitted light is bluish and bright, while the peripheral portion tends to be slightly dark with a yellowish color. When such a white light-emitting diode is condensed using a normal convex lens, the color characteristics of the light-emitting diode are directly reflected on the irradiation surface, and uniform color illumination cannot be performed.

  In addition, since the light emission colors of individual light emitting diodes vary, when a lighting device is configured using a plurality of light emitting diodes, uniform color illumination may not be possible due to variations in the light emission colors of the light emitting diodes. There is sex. In particular, when a configuration is adopted in which the irradiation range is different for each light emitting diode, the color differs depending on the irradiation region.

  In such a situation, when an illuminating device for an image pickup apparatus is configured by using a plurality of light emitting diodes, light beams from a plurality of light emitting diodes that are small and inexpensive and that are separated from each other are colored in accordance with the photographing field angle. It is necessary to irradiate so that there is no unevenness (brightness unevenness). Here, since the shooting angle of view is usually different between the left-right direction and the up-down direction, the corresponding illumination light irradiation angle also differs between the left-right direction and the up-down direction.

  In the dome-type light emitting diode element proposed in Patent Document 1, the light emitting diode element itself has a light condensing function, an optical system with high light condensing property can be realized. However, in order to manufacture such an illuminating device as cheaply as possible, it is necessary to select a ready-made light emitting diode having light emission characteristics as close as possible to the required irradiation range. Therefore, it is not always possible to perform efficient illumination that completely matches the required irradiation range.

  In addition to the light emitting diode element, an optical member for adjusting the irradiation range to the required irradiation angle range may be added. However, if the optical member is added to a plurality of large light-emitting diodes because the transparent resin portion is originally provided, the entire illumination device is increased in size. Furthermore, in the illumination device of Patent Document 1, no consideration is given to color, and color unevenness may occur on the irradiated surface.

  On the other hand, in the illumination device proposed in Patent Document 2, since a relatively large gap is formed between the light emitting diode and the convex lens, the light flux emitted from the light emitting diode escapes from this gap, and the light use efficiency is lowered. . Further, in the condensing optical system using only the refractive light beam by the convex lens, the portion near the center of the optical axis can be irradiated relatively brightly, but it is difficult to sufficiently spread the light beam to the peripheral portion. For this reason, it is difficult to perform illumination with uniform brightness over the entire required irradiation range, resulting in uneven light distribution. Further, even in this lighting device, no consideration is given to color unevenness.

Moreover, in the illuminating device proposed by patent document 3, since it concentrates mainly using a reflector, an optical system will enlarge. Further, if an efficient condensing optical system is configured for a plurality of light sources, a condensing optical system is required for each light source, and the optical system becomes larger.
Furthermore, it becomes an expensive illuminating device with an increase in the number of parts.

  In order to prevent the occurrence of uneven light distribution and uneven color, it is possible to provide a diffusing surface on the surface of the optical member or to contain a component that diffuses the light flux in the material of the optical member. However, it is generally known that when a diffusing surface or a diffusing component is added to an optical system, an extreme decrease in illuminance occurs.

Although the present invention is small and inexpensive, it can efficiently use a light beam emitted from a light emitting unit , and can shoot a subject by irradiating a subject with almost uniform light distribution characteristics and color distribution characteristics within a necessary irradiation range. An object of the present invention is to provide an imaging device that can perform the above.

In order to achieve the above object, an imaging apparatus according to the present invention includes a light emitting unit having a plurality of light sources, a plurality of incident surfaces on which light beams emitted from the plurality of light sources respectively enter, and the plurality of incident surfaces. An optical member comprising: an exit surface that emits a light beam incident from the light source ; and a reflective surface that guides the light beam incident from the plurality of incident surfaces provided to surround the optical axes of the plurality of light sources to the exit surface. And an imaging system that captures an image of a subject, and the vicinity of the exit surface of the region surrounded by the reflection surface of the optical member is a plane orthogonal to at least one of the optical axes of the plurality of light sources , The width of the first direction, which is the direction in which the angle of view in the imaging system is narrow, is wider than the width of the second direction orthogonal to the first direction, and the exit surface has a refractive power in the first direction. Greater than the refractive power in the second direction. The features.

According to the present invention, a small type and low cost, a light flux emitted from the light emitting portion can be efficiently utilized to shoot by irradiating the object moreover a substantially uniform light distribution characteristic and color distribution characteristics within the required irradiation range Can do.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of a digital camera (imaging device) including an illumination device that is Embodiment 1 of the present invention. In FIG. 1, 11 is a digital camera body, 12 is a lens barrel having a photographic lens, 14 is a CCD sensor or CMOS sensor for photoelectrically converting a subject image formed by the lens barrel 12 and acquiring an image. This is an image sensor. The lens barrel 12 and the imaging element 14 constitute an imaging system. Reference numeral 13 denotes an illuminating device according to this embodiment that irradiates a subject with illumination light.

  As shown in FIG. 1, the illumination device 13 according to the present embodiment is disposed on the front surface of the digital camera body 11 and at the upper right corner of the lens barrel 12 when viewed from the front surface.

  Note that the configuration of the digital camera other than the configuration of the illumination device is not limited at all, and the description thereof is omitted in this embodiment. In this embodiment, a digital still camera will be described as an example. However, the present invention can be applied to an illumination device used for various imaging devices such as a video camera and a single-lens reflex camera. The same applies to other embodiments described later.

  FIG. 2 shows the illuminating device 13 shown in FIG. 1 in an enlarged manner. The illumination device 13 of the present embodiment is arranged in a horizontal direction with a wider angle of view when the shooting field angle of the imaging system is viewed in the horizontal direction (left-right direction in the figure) and the vertical direction (up-down direction in the figure). The emitted light beams from the light emitting diodes (light emitting surfaces 1a, 2a, 3a) can be efficiently condensed.

  Usually, a flash using a discharge arc tube such as a xenon tube is often used as an illumination device of a digital camera. However, the illumination device of this embodiment is a light emitting diode whose optical characteristics have been rapidly improved in recent years. The use of a plurality effectively functions for both moving image shooting and still image shooting.

3 to 5, the illuminating device 13 is a normal line standing at the center of the light emitting surface of one light emitting diode 2, in other words, the vertical direction passing through the irradiation optical axis L of the light flux from one light emitting diode in the illuminating device 13. Sectional drawing when cut | disconnecting in the surface of a direction (1st direction) is shown. In FIGS. 4 and 5, a ray trace diagram of a representative light beam emitted from the center of the light emitting surface 2a (surface light source) of the light emitting diode 2 is appended.

  6 to 8 are cross-sectional views when the lighting device 13 is cut along a plane in the horizontal direction (second direction) passing through the irradiation optical axes L of the three light-emitting diodes 1, 2, and 3. FIG. 7 and 8 are ray trace diagrams of representative light beams emitted from the center of the light emitting surface 2a of the light emitting diode 2. FIG.

  In these drawings, the three light emitting diodes 1 to 3 are arranged at equal intervals in the horizontal direction. Reference numeral 4 denotes an optical member that condenses the light beams emitted from the light emitting diodes 1 to 3.

  A hard substrate 5 is electrically connected to the light emitting diodes 1 to 3 and holds the light emitting diodes 1 to 3. Reference numeral 6 denotes an exterior member of the digital camera body 11.

  The light emitting diodes 1 to 3 can emit white light having uniform color distribution characteristics, and can emit steady light for a certain period of time (light that is continuously emitted for a longer time than instantaneous light such as a flash). It is a high-intensity white light emitting diode. In order to emit white light with uniform color distribution characteristics, the light emitting diode of this embodiment absorbs part of the blue light and the light emitting diode chips 1b, 2b, and 3b that emit blue light. And a mold resinous diffusion surface in which a phosphor generating long-wavelength light is dispersed. White light is emitted by the color mixture of the blue light emitted from the light emitting diode chip and the long wavelength light emitted from the phosphor.

  The three light emitting diodes 1 to 3 have substantially the same optical characteristics (color distribution characteristics, intensity distribution characteristics of emitted light, etc.). Further, the three light emitting diodes 1 to 3 are diffused light emitting surfaces 1a, 2a, 2a, 2a, 2a, 2a, 2a, 2a, 2a, 2a, 2a, 2b, 2a, 2b, having a substantially circular shape and a finite area with respect to each other when viewed from the light irradiation direction. 3a. The light emitted from each light emitting diode chip is diffused by the diffusion light emitting surface, so that the light emitting diodes 1 to 3 emit light uniformly from almost the entire light emitting surface.

  The light emitting diodes 1 to 3 are electrically and mechanically connected to the hard substrate 5 by soldering or the like, and emit light when receiving a control signal from a CPU (not shown) via the hard substrate 5. The hard substrate 5 is fixed to a predetermined position in the digital camera body 11 by a fixing member (not shown), specifically, to a position separated by a predetermined interval so as to function most efficiently as an illumination optical system.

  The optical member 4 is integrally formed of a highly transparent optical resin material, and efficiently converges the light beams emitted from the three light emitting diodes 1 to 3 arranged at a predetermined interval in a necessary irradiation range. The optical member 4 has three entrance surfaces 4a provided for each light emitting diode, and a common exit surface 4b. Further, one reflection diode 4c is provided for each light-emitting diode, and reflects three light beams incident from the incident surface 4a and guides them to the emission surface 4b. Hereinafter, a part of the incident surface 4a, the reflecting surface 4c, and the emitting surface 4b through which the light beam emitted from one light emitting diode of the optical member 4 passes or reflects is referred to as a light guide region for the light emitting diode. That is, the optical member 4 of the present embodiment has three light guide regions corresponding to the three light emitting diodes 1 to 3.

The outer shape of each incident surface 4a when viewed in the direction of the irradiation optical axis is substantially circular, which is the same as the shape of the light emitting surface of the light emitting diode. The incident surface 4a is a surface substantially orthogonal to the irradiation optical axis L. Here, substantially perpendicular means includes a case where inclined with respect to an amount corresponding plane perpendicular to the irradiation optical axis L of or mechanical errors completely orthogonal. The same applies to the following embodiments.

  The size (diameter) of each incident surface 4a is substantially the same as the size (diameter) of the light emitting surface of each light emitting diode. Note that the size and shape in the present embodiment are substantially the same, including the case where they are completely the same and the case where they are different to the extent that they include errors due to the accuracy in manufacturing the optical member 4. The same applies to the following embodiments.

  In the optical member 4, the three incident surfaces 4 a are positions close to the light emitting surfaces 1 a, 2 a, 3 a of the light emitting diodes 1 to 3, and the light emitting surfaces 1 a, 2 a on the irradiation optical axis L. , 3a.

  Here, when the size of the incident surface 4a is smaller than the size of the light emitting surface, all the light beams emitted from the light emitting surface cannot be incident on the incident surface 4a. On the other hand, when the incident surface 4a is larger than the light emitting surface, the optical member 4 is increased in size. In addition, the light flux reaching the periphery of the incident surface 4a is reduced, and the light distribution on the incident surface 4a becomes non-uniform, resulting in uneven light distribution. Therefore, it is desirable that the incident surface 4a and the light emitting surfaces 1a, 2a, and 3a have substantially the same size as in this embodiment.

  The exit surface 4b of the optical member 4 has a positive refracting power in the vertical direction as shown in FIGS. 3 to 5 and has no refracting power in the horizontal direction as shown in FIGS. It is a lens surface. As a result, in the vertical cross section shown in FIG. 4, a part of the light beam emitted from the light emitting diode 2 and incident on the incident surface 4a is directly directed to the emergent surface 4b and refracted on the emergent surface 4b and collected at a predetermined irradiation angle. Lighted.

  Also, as shown in FIG. 2, when the optical member 4 is viewed from the irradiation optical axis direction, attention is paid to a region (hereinafter referred to as an emission region) 4d through which the light flux from each light-emitting diode passes in the emission surface 4b. The opening area of the emission region 4d is larger than the opening area of the incident surface 4a. In particular, in the vertical section, the opening width of the exit region at the exit surface 4b is larger than the opening width of the entrance surface 4a as compared to the horizontal section. For this reason, the opening shape of each injection region 4d is a substantially elliptical shape with the vertical direction as the major axis direction.

  Each reflecting surface 4c of the optical member 4 reflects the remaining light beam out of the light beams emitted from each light emitting diode and incident on each incident surface 4a, and guides it to the emitting surface 4b. Here, the reflecting surface 4c is formed of a curved surface. Specifically, the shape of the reflection surface 4c is such that the area (diameter) when the optical member 4 is cut by a surface orthogonal to the irradiation optical axis L is continuously increased from the incident surface 4a toward the emission surface 4b. The shape is increasing. Also in this case, as shown in FIG. 5, the light beam that is emitted from the light emitting diodes 1 to 3 and is incident on the incident surface 4a is reflected by the reflecting surface 4c and then refracted by the emitting surface 4b toward the emitting surface 4b. As in the case of the light beam shown in FIG.

  Next, the shape of the reflective surface 4c of the present embodiment will be described in more detail. First, the shape of the reflecting surface 4c in the vertical cross section will be described.

In FIG. 3, the outer edge portion of the optical member 4 from the vertical end A of the exit surface 4b to the vertical end B of the entrance surface 4a approaches the end B on the entrance surface side from the end A on the exit surface side. As a result, a continuous curve shape is formed in which the angle formed by the tangent to the normal line n standing at the end A is increased. In other words, the outer edge portion has a horn shape in which the angle formed with respect to the irradiation optical axis L gradually increases from the end B side toward the end A side. And the reflective surface 4c is formed from the edge part B to the edge part A vicinity among this outer edge part. In addition, the part between the edge part A in the optical member 4 and the edge by the side of the edge part A in the reflective surface 4c is a connection part with the light guide area | region for light emitting diodes adjacent in a horizontal direction.

  With such a shape, the light beam directly reaching the vertical end A of the exit surface 4b and the light beam reflected by the region on the exit surface 4b side of the reflective surface 4c are continuously transmitted from the light incident surfaces 4a. It is effective to distribute it. By adopting this reflecting surface shape, the angle of the light beam reaching the end A among the direct light beam directly reaching the exit surface 4b and the irradiation light axis L of the reflected light beam via the reflecting surface 4c. Can be made substantially equal to the angle of the light beam forming the maximum angle with respect to. As a result, the discontinuity between the direct light and the reflected light beam can be avoided.

Moreover, the area | region (area | region containing the edge part B) which touches the entrance plane 4a among the reflective surfaces 4c is connected with the entrance plane 4a set to the shape (size) substantially the same as the light emission surface of a light emitting diode as mentioned above. It is formed as follows. In other words, the region of the reflecting surface 4c that is in contact with the incident surface 4a is formed in a substantially circular shape when viewed in the direction of the irradiation optical axis (viewed in the direction of the outgoing optical axis) , as indicated by a broken line in FIG.

  Further, as described above, the reflecting surface 4c is formed of a horn-shaped curved surface. This is due to the following reason. Originally, the light beam reflected by the reflecting surface 4c is a component refracted once by the incident surface 4a formed by a plane. For this reason, in the optical system in which the length of the optical member 4 in the irradiation optical axis direction is relatively short as in the present embodiment, there are few components reaching the reflecting surface 4c, and the angular range of the components is also relatively narrow. On the other hand, as an illuminating device, it is desirable that the angle distribution of the reflected light reflected by the reflecting surface 4c and the angle distribution of the direct light reaching the exit surface 4b directly from the incident surface 4a are substantially the same. Therefore, in this embodiment, in order to widen the angular distribution of the light beam that has reached the reflecting surface 4c, the shape of the reflecting surface 4c is a horn-shaped curved surface, thereby making the light distribution characteristics of the emitted light uniform.

  Here, in order to simplify the description, the angular distribution characteristics of the light beam that has hit the reflecting surface 4c when the reflecting surface 4c is a curved surface having an arc cross section will be described. First, for comparison, when the reflecting surface 4c is a surface having a straight cross section, the way in which the light beam spreads does not change before and after the reflection at the reflecting surface 4c. Further, in the case where the reflecting surface 4c has an arc cross section, when the center of the arc is on the irradiation optical axis L side with respect to the straight line, the angle distribution after reflection becomes narrow. Conversely, when the center of the arc is on the opposite side of the irradiation optical axis L across the straight line, that is, in the case of a horn-shaped curved surface as in the present embodiment, the luminous flux after being reflected by the reflecting surface 4c It becomes possible to widen the angle distribution compared to before reflection.

  Next, the curvature of the reflecting surface 4c will be described. The angular distribution of reflected light can be changed by the curvature of the reflecting surface 4c. As described above, in the case of the present embodiment in which the length of the optical component 4 in the irradiation optical axis direction is short, the reflected light beam component is small, and it is necessary to change the angle greatly before and after the reflection. For this reason, the reflective surface 4c needs to be a curved surface having a relatively large curvature. When the length of the optical member in the direction of the optical axis of the optical member is long, there are many light flux components that hit the reflecting surface, and a large angle change is not required before and after reflection. The light distribution characteristics can be obtained.

  Further, the reflecting surface 4c is configured to totally reflect the light beam from the incident surface 4a toward the exit surface 4b. Here, almost all of the light flux from the incident surface 4a can be reflected by making the reflective surface 4c into a highly reflective metal vapor-deposited surface by vapor deposition or the like.

  However, when the reflection surface 4c is a total reflection surface, it is not necessary to perform a vapor deposition process or the like, so that the manufacturing cost of the optical member 4 can be reduced and the manufacturing cost of the optical member 4 can be reduced. Also, from the viewpoint of optical characteristics, a total reflectance of 100% (actually close to 100%) can be obtained theoretically, so that an efficient illumination optical system with little light loss is constructed. can do.

  Next, the cross-sectional shape of the illuminating device of a present Example in the horizontal direction is demonstrated using FIGS. The illumination device of the present embodiment is intended to efficiently irradiate light beams emitted from a plurality of light sources to a necessary irradiation range corresponding to an imaging field angle. As described above, normally, the imaging field angle is different between the horizontal direction and the vertical direction. In this case, the most efficient irradiation method is to vary the light distribution in the necessary irradiation range that varies depending on the direction.

  However, there is no conventional illumination device in which the irradiation angle of the luminous flux emitted from the light emitting diode is different between the horizontal direction and the vertical direction, and the irradiation angle in either direction is often spread more than necessary. . In contrast, in this embodiment, a light source having no directivity in the horizontal direction and the vertical direction, that is, a light source that emits a light beam with almost the same distribution in all directions is used, and the distance from the light source to the exit surface is limited to be small. The light distribution characteristics can be made different between the horizontal direction and the vertical direction.

In this embodiment, in order to achieve the above object, as shown in FIGS. 6 to 8, a desired light distribution characteristic is obtained by using a condensing method different from that in the vertical direction in the horizontal direction. Since the shapes of the three light guide regions of the optical member 4 with respect to the three light emitting diodes 1, 2, and 3 are the same as each other, FIGS. 7 and 8 show ray tracing diagrams only for the light emitting diode 2 as a representative. It is added.
The trace of the light flux from the light emitting diodes 1 and 3 is almost the same as this.

  First, as described above, the exit surface 4b of the optical member 4 has no refractive power in the horizontal direction (see FIG. 6). As shown in FIG. 7, some of the light beams emitted from the respective light emitting diodes and incident on the incident surface 4a are directly directed to the emergent surface 4b and refracted by the emergent surface 4b to be emitted as components of a predetermined irradiation angle. To do. In this case, the emitted light beam is limited in angle only by the opening area of the emission region corresponding to each light emitting diode on the emission surface 4b.

  Further, in the horizontal direction, the opening width of the emission region corresponding to each light emitting diode on the emission surface 4b is larger than the opening width of the incident surface 4a. That is, in the horizontal direction, the emission area of each light emitting diode on the emission surface 4b is formed larger than the incidence surface 4a. However, the opening width of the emission region in the horizontal direction is narrower than the opening width in the vertical direction shown in FIG. Therefore, as described above, the opening shape of each emission region 4d on the emission surface 4b is substantially elliptical with the vertical direction as the major axis direction.

  The reflection surface 4c reflects and guides the light beam other than the light beam (direct light beam) directed to the direct emission surface 4b out of the light beam emitted from each light emitting diode and incident on the incident surface 4a to the emission surface 4b. Here, the reflection surface 4c is configured to have a linear shape having a certain inclination with respect to the irradiation optical axis L in the cross section in the horizontal direction. Also in this case, as shown in FIG. 8, the light beam (reflected light beam) reflected by the reflecting surface 4c out of the light beams emitted from the respective light emitting diodes and incident on the incident surface 4a undergoes refraction at the emitting surface 4b, Similarly to the luminous flux shown in FIG.

  The degree of condensing in this case is defined by the inclination angle of the reflecting surface 4c with respect to the irradiation optical axis L and the length (depth) of the optical member 4 in the irradiation optical axis direction. The smaller the tilt angle of the reflecting surface 4c is, and the greater the depth of the optical member 4 is, the more uniformly the light beam can be condensed. On the other hand, even when the angle of inclination of the reflecting surface 4c is slightly large and the depth of the optical member 4 is small, the reflecting surface 4c is relatively small and can have a certain degree of light collecting effect.

  In the present embodiment, in consideration of both, in order to balance the size and the degree of light condensing within the given depth of the optical member 4, light condensing is performed only by the light condensing effect due to the inclination of the reflecting surface 4c. Yes. That is, as shown in the figure, the reflected light beam is converted into an irradiation angle component substantially similar to the direct light beam shown in FIG. 7 by total reflection by the reflecting surface 4c. Further, as shown in FIG. 8, the reflected light flux is larger in the horizontal direction than in the vertical direction shown in FIG. In addition, the angular distribution of the light flux before and after the reflection on the reflection surface 4c hardly changes because the shape of the reflection surface 4c in the horizontal section is a straight line.

  As described above, in this embodiment, the shape of the reflecting surface 4c of the optical member 4 is different between the vertical section (FIGS. 3 to 5) and the horizontal section (FIGS. 6 to 8). Thereby, although the distance from each light emitting diode to the exit surface 4b of the optical member 4 is the same in the vertical section and the horizontal section, the light distribution characteristics in the vertical direction and the horizontal direction of the emitted light flux The light distribution characteristics can be controlled independently of each other. Specifically, in the vertical direction, the light distribution characteristics are controlled by the interaction between the cylindrical lens on the exit surface 4b and the reflecting surface 4c formed of a curved surface, and in the horizontal direction, the light distribution is performed only by the action of the reflecting surface 4c. Control properties. For this reason, it is possible to perform efficient illumination with less irradiation of a light beam to an unnecessary region with respect to the imaging field angle.

  Here, the exit side end portion of the reflection surface 4c has an elliptical shape with the vertical direction as the major axis direction when viewed in the irradiation optical axis direction. That is, the shape of the reflecting surface 4c is different between the end on the incident surface 4a side and the end on the exit surface 4b side. Thereby, in the cross section in a direction different from the vertical direction and the horizontal direction, the light distribution characteristics in the vertical direction and the light distribution characteristics in the horizontal direction are continuously changed.

  Further, in this embodiment, the light emitting diodes 1 to 3 have the same shape, and the light distribution characteristics of the light beams from the respective light emitting diodes controlled by the optical member 4 are configured to obtain substantially equivalent characteristics. Then, by superimposing the light beams from these three light emitting diodes, a light distribution characteristic corresponding to the imaging field angle can be obtained. This is because, for example, when the subject distance is short and the light quantity is sufficient even if all the light emitting diodes 1 to 3 are not used, the necessary light quantity and light distribution characteristics are obtained by the light emission of one or two light emitting diodes. It is the structure which considered making it obtain. In addition, by superimposing the light beams emitted from the plurality of light emitting diodes 1 to 3 and emitted from the optical member 4, differences in the light emission amount due to component tolerance, color characteristics of individual light emitting diodes, and differences in light emission efficiency can be obtained. It can be absorbed as a whole. Thereby, a uniform and efficient illumination optical system can be configured.

  In this embodiment, an example in which three light emitting diodes are used has been described. However, in the present invention, the number of light sources is not limited to this, and may be two or four or more.

  Further, in this embodiment, an example in which a lens shape is added to the exit surface 4b of the optical member 4 in the vertical cross section has been described. However, in the present invention, a lens shape can also be added in the horizontal direction. In this case, toric lens surfaces having different refractive powers in the vertical direction and the horizontal direction may be added. If necessary, a lens surface may be added to the incident surface 4a.

  Further, in this embodiment, an example in which white light is emitted using a white light emitting diode has been described. However, the present invention is not limited to this, and, for example, blue, red, and green light emitting diodes are used and the three colors are used. It is also possible to irradiate white light by synthesizing.

  In the present embodiment, the example in which the three light emitting diodes are arranged in the horizontal direction has been described. However, the arrangement of the plurality of light sources of the present invention is not limited to this. For example, by arranging a plurality of light emitting diodes in a zigzag pattern when viewed in the direction of the irradiation optical axis, the horizontal length of the light emitting unit of the lighting device is larger than the case where the same number of light emitting diodes are arranged in a row in the horizontal direction. Can be shortened. In the present embodiment, the case where a plurality of light emitting diodes are collectively arranged at the corner of the camera body 11 has been described. However, a plurality of light sources and optical members may be arranged at positions apart from each other. Further, a plurality of light emitting diodes may be arranged in a vertical line along the side surface of the camera.

  FIG. 9 shows a schematic configuration of a digital camera (imaging device) including an illumination device that is Embodiment 2 of the present invention. In FIG. 9, 28 is a digital camera body, 281 is a lens barrel having a photographing lens, 282 is a CCD sensor or CMOS sensor for photoelectrically converting a subject image formed by the lens barrel 281 and acquiring an image. This is an image sensor. The lens barrel 281 and the imaging element 282 constitute an imaging system. Reference numeral 29 denotes an illuminating device according to this embodiment that irradiates a subject with illumination light.

  As shown in FIG. 9, the illumination device of the present embodiment is disposed on the front surface of the digital camera body 28 and at the upper right corner of the lens barrel 281 when viewed from the front surface.

  FIG. 10 shows the illuminating device 29 shown in FIG. 9 in an enlarged manner. The illumination device 29 of the present embodiment is arranged in a horizontal direction with a wider angle of view when the shooting field angle of the imaging system is viewed in the horizontal direction (left-right direction in the figure) and the vertical direction (up-down direction in the figure). The emitted light beams from the light emitting diodes (light emitting surfaces 21a, 22a, 23a) can be efficiently condensed.

  As in the first embodiment, the illumination device 29 according to the present embodiment efficiently collects light beams emitted from a plurality of light emitting diodes arranged at predetermined intervals. However, the light emitting diode as a light source is different from the first embodiment in that the shape of the light emitting diode is square and the light emitting surface of an optical member described later is a flat surface. Also, the shape of the incident surface of the optical member is different from that of the first embodiment.

  11 to 13 are cross-sectional views when the lighting device 29 is cut along a plane in the vertical direction (first direction) passing through the irradiation optical axis L from one light emitting diode 22. In FIGS. 12 and 13, ray tracing diagrams of representative light beams emitted from the center of the light emitting surface 22 a of the light emitting diode 22 are added.

  14 to 16 are cross-sectional views when the lighting device 29 is cut along a plane in the horizontal direction (second direction) passing through the irradiation optical axis L from the three light-emitting diodes 21, 22, and 23. FIG. . 15 and 16 are attached with ray tracing diagrams of representative light beams emitted from the center of the light emitting surface 22a of the light emitting diode 22. FIG.

  In these drawings, the three light emitting diodes 21 to 23 are arranged at equal intervals in the horizontal direction. Reference numeral 24 denotes an optical member that condenses the light beams emitted from the light emitting diodes 21 to 23.

  A hard substrate 25 is electrically connected to the light emitting diodes 21 to 23 and holds the light emitting diodes 21 to 23. Reference numeral 26 denotes an exterior member of the digital camera body 28.

  The light-emitting diodes 21 to 23 are high-intensity white light-emitting diodes that can emit white light with uniform color distribution characteristics and can emit stationary light for a certain period of time, as in the first embodiment. The three light emitting diodes 21 to 23 have almost the same optical characteristics (color distribution characteristics, intensity distribution characteristics of emitted light, etc.). The three light-emitting diodes 21 to 23 are diffused light-emitting surfaces 21a, 21a, 21b, 21a, 21b, 21a, 21b, 21a, 21b, 21a, 21b, 21b, 21a, 21b, 21b, 21b, 21b 22a and 23a. The light emitted from each light emitting diode chip is diffused by the diffuse light emitting surface, so that the light emitting diodes 21 to 23 emit light uniformly from almost the entire light emitting surface.

  The light emitting diodes 21 to 23 are electrically and mechanically connected to the hard substrate 25 by soldering or the like, and emit light when receiving a control signal from a CPU (not shown) via the hard substrate 25. The hard substrate 25 is fixed to a predetermined position in the digital camera main body 28 by a fixing member (not shown), specifically, a position separated by a predetermined interval so as to function most efficiently as an illumination optical system.

  The optical member 24 is integrally formed of a highly transparent optical resin material, and efficiently collects the light beams emitted from the three light emitting diodes 21 to 23 arranged at a predetermined interval in a necessary irradiation range. The optical member 24 has a total of nine incident surfaces 24a and 24b provided three by three for one light emitting diode, and a common exit surface 24c. Further, two light emitting diodes are provided for each of the light emitting diodes, and a total of twelve reflecting surfaces 24d and 24e that reflect the light beam incident from the incident surface 24b and guide it to the exit surface 24c are provided. Here, a part of the incident surfaces 24a and 24b, the reflecting surfaces 24d and 24e, and the exit surface 24c through which the light beam emitted from one light emitting diode of the optical member 24 passes or reflects is guided to the light emitting diode. It is called an area. That is, the optical member 24 of the present embodiment has three light guide regions corresponding to the three light emitting diodes 21 to 23.

  Here, the incident surfaces 24a and 24b have different shapes in the vertical direction and the horizontal direction. The reflecting surfaces 24d and 24e also have different shapes in the vertical direction and the horizontal direction.

  Of the incident surfaces 24a and 24b on which light beams emitted from the respective light emitting diodes are incident, the incident surface 24a formed at the central portion including the irradiation optical axis L is the light emitting surface of the light emitting diode when viewed from the irradiation optical axis direction. It has the same substantially square shape. In the vertical cross section shown in FIG. 11, the incident surface 24a is formed as a convex cylindrical lens surface on the light emitting diode side. In addition, incident surfaces 24b formed above and below the incident surface 24a extend from the upper and lower ends of the incident surface 24a toward the light emitting diode.

  As shown in FIG. 14, a pair of reflecting plates 27 are arranged so as to cover both horizontal ends of the incident surfaces 24a and 24b. This is because the emission angle in the horizontal direction of the emitted light beam from the light emitting diode is large, and the light beam that could not be incident on the incident surfaces 24a and 24b escapes in the horizontal direction as it is, thereby preventing the light utilization efficiency from decreasing. Is to do. The reflection plate 27 is configured by a metal reflection plate having a high reflectance on the side on which the light beam enters or a reflection plate obtained by performing metal deposition on a thin resin material to obtain a high reflectance.

  Here, when the region surrounded by the ridge line portion on the light emitting diode side of the incident surface 24b and the end portion on the light emitting diode side of the reflecting plate 27 is an incident region, the incident region is a light emitting diode in the irradiation optical axis direction view. The light emitting surface has the same substantially square shape. Further, the incident area has substantially the same size as the light emitting surface of the light emitting diode. The incident surface 24a of the optical member 24 is disposed at a position separated from the light emitting surface of the light emitting diode by the length of the incident surface 24b in the irradiation optical axis direction, and the light beam emitted from the light emitting diode is incident on the incident surface 24a. It is configured to be refracted and condensed. Further, the incident surface 24a is disposed on the irradiation optical axis L so as to face the light emitting surface.

  On the other hand, the incident surface 24b allows a light beam having a larger exit angle with respect to the irradiation optical axis L than a light beam incident on the incident surface 24a out of the light beam emitted from the light emitting surface of the light emitting diode to escape from between the light emitting surface and the incident surface 24a. It is the 2nd entrance plane formed so that there may not be. The light beam incident from the incident surface 24b is refracted by the incident surface 24b, is totally reflected by the reflecting surface 24d, receives a predetermined light condensing action, and then travels to the exit surface 24c. In this way, by providing a plurality of incident surfaces according to the angle of the light beam emitted from the light emitting diode, it becomes possible to separate and independently control the light beam emitted from the light emitting diode, and to collect light efficiently. It becomes possible.

  Here, when the size of the incident region surrounded by the ridge line on the light emitting diode side of the incident surface 24b and the end surface on the light emitting diode side of the reflector 27 is smaller than the size of the light emitting surface of the light emitting diode, the light is emitted from the light emitting surface. All the luminous fluxes thus made cannot enter the optical member 24. In addition, when the size of the incident region is too larger than the size of the light emitting surface, the optical member 24 is increased in size. Therefore, it is desirable to make the size of the incident region substantially equal to the light emitting surface of the light emitting diode as in this embodiment.

  The exit surface 24c of the optical member 24 is a plane substantially orthogonal to the irradiation optical axis L as shown in FIGS. Thereby, the freedom degree in the external appearance surface of a camera can be increased.

As shown in FIG. 12 and FIG. 13, in the vertical cross section, the light beam emitted from the light emitting diode 22 and incident on the incident surface 24a is directly directed to the emergent surface 24c and condensed in a predetermined irradiation angle. Injected from member 24. On the other hand, of the light beam emitted from the light emitting diode 22, the light beam incident from the upper and lower incidence surfaces 24b is totally reflected by the reflection surface 24d and guided to the emission surface 24c. The progress of such a light beam is the same for the light beams emitted from the other light emitting diodes 21 and 23.

  Here, the reflection surface 24d is formed in a curved surface shape that becomes concave toward the irradiation optical axis L, as shown in FIGS. Further, when the optical member 24 is cut along a plane orthogonal to the irradiation optical axis L, the reflecting surface 24d continuously increases in distance from the irradiation optical axis L as the cutting position approaches the exit surface 24c. It has such a shape. Unlike the reflecting surface 4c described in the first embodiment, the reflecting surface 24d has an effect of narrowing the angular distribution of the light beam reflected by the reflecting surface 24b from the angular distribution of the light beam before reflection. For this reason, as shown in FIG. 13, the light beam emitted from the light emitting diode 22 and reflected by the reflecting surface 24d is emitted from the optical member 24 in a very condensed state.

  Further, as shown in FIG. 10, when the optical member 24 is viewed from the irradiation optical axis direction, the opening of the region (exit region) 24f through which the light flux from each light-emitting diode passes is formed on the incident surface 24a. It has a rectangular shape larger than the opening.

  Next, the cross-sectional shape in the horizontal direction of the illuminating device of a present Example is demonstrated using FIGS.

  In this embodiment, as shown in FIGS. 14 to 16, the light distribution characteristics are determined by a condensing method different from that in the vertical direction in the horizontal direction, that is, only by the reflection surface 24e. Since the shapes of the three light guide regions of the optical member 24 with respect to the three light emitting diodes 21, 22, and 23 are the same, FIG. 15 and FIG. 16 show ray tracing diagrams only for the light emitting diode 22 as a representative. It is added. The trace diagrams of the light beams from the light emitting diodes 21 and 23 are almost the same.

  First, as shown in FIG. 14, the exit surface 24c of the optical member 24 has a planar shape having no refractive power. A part of the light beam emitted from each light emitting diode and incident on the incident surface 24a is directly directed to the emission surface 24c, refracted by the emission surface 24c, and emitted in a predetermined irradiation angle range. This is the same as that shown in FIG. 7 of the first embodiment, and the irradiation angle is determined by the opening width of the exit surface (injection region).

  On the other hand, the reflecting surface 24e reflects and guides the light beam other than the light beam directly directed to the emission surface 24c out of the light beams emitted from the respective light emitting diodes and incident on the incident surface 24a to the emission surface 24c. Further, among the light beams emitted from the respective light emitting diodes, a light beam that has a large angle with respect to the irradiation optical axis L and cannot be directly incident on the incident surface 24a can be obtained by using reflection on the reflecting plate 27 as shown in FIG. 24a. As a result, the luminous flux emitted from each light emitting diode can be effectively utilized without leaving any excess. Here, the reflecting surface 24e is configured as a plane having a certain inclination with respect to the irradiation optical axis L in the horizontal cross section. In this case, as shown in FIG. 16, the light beam totally reflected by the reflecting surface 24e out of the light beam incident from the incident surface 24a into the optical member 24 is directed to the exit surface 24c and is refracted by the exit surface 24c. It is condensed in the irradiation angle range. As shown in FIG. 16, the angular distribution range of the light beam (reflected light beam) emitted after being totally reflected by the reflecting surface 24e is substantially the same as the direct light beam directed from the incident surface 24a toward the direct exit surface 24c shown in FIG. Converted to the irradiation angle range.

  As a feature of the optical system, first, regarding the vertical cross section shown in FIGS. 11 to 13, an optical system with high light condensing property can be configured at a very close distance from the light emitting diodes 21 to 23, but the aperture width is There is a tendency to become somewhat wide. On the other hand, in the horizontal cross section shown in FIGS. 14 to 16, by increasing the number of reflections, it is possible to realize a light distribution characteristic in which the irradiation angle range is narrowed with a relatively narrow aperture width. The total length tends to be slightly longer. In any of the cross sections in any direction, the light beams emitted from the light emitting diodes 21 to 23 can be used very effectively and can be within a relatively narrow irradiation angle range. Further, as a characteristic of the light emitting diode, a light beam emitted near the optical axis is a blue light beam, and a light beam emitted at a relatively large angle with respect to the optical axis tends to be a yellow light beam. However, in the illumination optical system used in the present embodiment, the direct light flux and the reflected light flux are overlapped in the same irradiation angle range, thereby making it difficult for color unevenness to occur.

  As described above, in the illumination device of the present embodiment, the shapes of the incident surfaces 24a and 24b and the reflecting surfaces 24d and 24e in the vertical direction and the horizontal direction are different. Thereby, although the distance from the light emitting diode to the emission surface 24c is the same, the light distribution characteristic in the vertical direction and the light distribution characteristic in the horizontal direction can be controlled independently. Therefore, efficient illumination can be performed in the necessary irradiation range corresponding to the imaging field angle. That is, it is possible to reduce the luminous flux irradiated outside the necessary irradiation range.

  Further, regarding the cross section in the direction other than the vertical direction and the horizontal direction, as shown in FIG. 10, the reflection surfaces 24d and 24e are rectangular emission areas (areas where the light beams from the respective light emitting diodes are emitted) on the emission surface 24c. ) The shape is set so as to form 24f. For this reason, a plurality of injection regions can be formed with almost no gap with respect to a rectangular opening space that is long in the horizontal direction of a given emission surface 24c. Therefore, efficient illumination can be performed.

  In the present embodiment, the light emitting diodes 21 to 23 have the same shape, and the light distribution characteristics controlled by the optical member 24 are substantially equivalent characteristics. And the predetermined light distribution characteristic with respect to a required irradiation range is acquired by superimposing the irradiation light beam by these three light emitting diodes. Similar to the first embodiment, by superimposing the luminous fluxes from a plurality of light sources, it is possible to absorb the difference in the light emission amount due to the difference in the component tolerance, the color characteristics of each light emitting diode and the light emission efficiency as a whole. It is possible to configure a uniform and efficient illumination optical system.

  In this embodiment, an example in which three light emitting diodes are used has been described. However, in the present invention, the number of light sources is not limited to this, and may be two or four or more.

  Furthermore, in the present embodiment, an example in which the exit surface 24c of the optical member 24 is a flat surface has been shown, but a lens shape can be added to the exit surface.

  Further, in this embodiment, an example in which white light is emitted using a white light emitting diode has been described. However, the present invention is not limited to this, and, for example, blue, red, and green light emitting diodes are used and the three colors are used. It is also possible to irradiate white light by synthesizing.

  In the present embodiment, the example in which the three light emitting diodes are arranged in the horizontal direction has been described. However, the arrangement of the plurality of light sources of the present invention is not limited to this. For example, by arranging a plurality of light emitting diodes in a zigzag pattern when viewed in the direction of the irradiation optical axis, the horizontal length of the light emitting unit of the lighting device is larger than the case where the same number of light emitting diodes are arranged in a row in the horizontal direction. Can be shortened. In the present embodiment, the case where a plurality of light emitting diodes are collectively arranged at the corner of the digital camera main body 28 has been described. However, a plurality of light sources and optical members may be arranged at positions apart from each other. Further, a plurality of light emitting diodes may be arranged in a vertical line along the side surface of the camera.

  FIG. 17 shows a schematic configuration of a digital camera (imaging device) including an illumination device that is Embodiment 3 of the present invention. In FIG. 17, 38 is a digital camera body, 381 is a lens barrel having a photographic lens, 382 is a CCD sensor or CMOS sensor for photoelectrically converting a subject image formed by the lens barrel 381 to obtain an image, etc. This is an image sensor. The lens barrel 381 and the imaging element 382 constitute an imaging system. Reference numeral 39 denotes an illuminating device according to the present embodiment that irradiates a subject with illumination light.

  As shown in FIG. 17, the illumination device of the present embodiment is disposed on the front surface of the digital camera body 38 at the upper right corner of the lens barrel 381 when viewed from the front surface.

  FIG. 18 is an enlarged view of the illumination device 39 shown in FIG. The illumination device 39 of the present embodiment is arranged in a horizontal direction with a wider field angle when the shooting field angle of the imaging system is viewed in the horizontal direction (left-right direction in the figure) and the vertical direction (up-down direction in the figure). The emitted light beams from the light emitting diodes (light emitting surfaces 31a, 32a, 33a) can be efficiently condensed.

  As in the first embodiment, the illumination device 39 according to the present embodiment efficiently collects light beams emitted from a plurality of light-emitting diodes having a light-emitting surface of a light-emitting diode that is substantially circular and arranged at a predetermined interval. Let However, the illumination device 39 of the present embodiment is different from the first embodiment in which the irradiation range is fixed in that the irradiation range of light can be changed.

  19 to 21 are cross-sectional views when the lighting device 39 is cut along a plane in the vertical direction (first direction) passing through the irradiation optical axis L from one light emitting diode 32. FIG. These figures show the case where the irradiation range is minimized. FIGS. 20 and 21 are attached with ray tracing diagrams of representative light beams emitted from the center of the light emitting surface 32a of the light emitting diode 32. FIG.

  FIGS. 22 to 24 show the case where the irradiation range is maximized in the vertical cross section. 23 and 24, a ray trace diagram of a representative light beam emitted from the center of the light emitting surface 32a of the light emitting diode 32 is appended.

  Further, FIGS. 25 to 27 show cross-sectional views when the illumination device 39 is cut along a plane in the horizontal direction (second direction) passing through the irradiation optical axis L of the three light emitting diodes 31, 32 and 33. These figures show the case where the irradiation range is minimized. 26 and 27, a ray trace diagram of a representative light beam emitted from the center of the light emitting surface 32a of the light emitting diode 32 is appended.

  FIGS. 28 to 30 show cases where the irradiation range is maximized in the horizontal cross section. In FIGS. 29 and 30, ray tracing diagrams of representative light beams emitted from the center of the light emitting surface 32 a of the light emitting diode 32 are appended.

  In these drawings, the three light emitting diodes 31 to 33 are arranged at equal intervals in the horizontal direction. Reference numeral 34 denotes an optical member that condenses the light beams emitted from the light emitting diodes 31 to 33.

  A hard substrate 35 is electrically connected to the light emitting diodes 31 to 33 and holds the light emitting diodes 31 to 33. Reference numeral 36 denotes an exterior member of the digital camera body 38.

  The light-emitting diodes 31 to 33 are high-intensity white light-emitting diodes that can emit white light having uniform color distribution characteristics and emit steady light for a certain period of time, as in the first embodiment. The three light emitting diodes 31 to 33 have substantially the same optical characteristics (color distribution characteristics, intensity distribution characteristics of emitted light, etc.). In addition, the three light emitting diodes 31 to 33 are diffused light emitting surfaces 31a, 31a, having a substantially circular shape and a finite area having the same size as each other when viewed from the irradiation optical axis direction on the front surface (light irradiation side portion) of the light emitting diode chip. 32a and 33a. The light emitted from each light emitting diode chip is diffused by the diffusion light emitting surface, so that the light emitting diodes 31 to 33 emit light uniformly from almost the entire light emitting surface.

The light emitting diodes 31 to 33 are electrically and mechanically connected to the hard substrate 35 by soldering or the like, and emit light when receiving a control signal from a CPU (not shown) via the hard substrate 35. The hard substrate 35 is held by a movable member 73 that is movable in the irradiation optical axis direction (the optical axis direction of the photographing lens). In the rack gear portion formed on the movable member 73, the output of the pinion gear 72 of the motor 71 is meshed at the final stage via a reduction gear train (not shown). For this reason, when the motor 71 is rotated by the drive signal from the CPU, the light emitting diodes 31 to 33 are moved (relatively moved) in the irradiation optical axis direction together with the movable member 73 and the hard substrate 35. Thereby, the relative distance in the irradiation optical axis direction of the light emitting diodes 31 to 33 and the optical member 34 changes, and the irradiation range can be changed. The illumination device 39 of the present embodiment is configured to function most efficiently as an illumination optical system even if the relative distance between the light emitting diodes 31 to 33 and the optical member 34 in the irradiation optical axis direction changes. Yes.

  The optical member 34 is integrally formed of a highly transparent optical resin material, and efficiently concentrates the light beams emitted from the three light emitting diodes 31 to 33 arranged at a predetermined interval in a necessary irradiation range. The optical member 34 has a total of six incident surfaces 34a and 34b provided two for each light emitting diode, and a common exit surface 34c. Further, one reflection diode 34d is provided for each light emitting diode, and reflects the light beam incident from the incident surface 34b and guides it to the emission surface 34c. 25 to 30, in order to explain the difference between the shapes of the incident surface 34 b and the reflecting surface 34 c with respect to the vertical cross section, the incident surface 34 b and the reflecting surface 34 c are given different reference numerals 34 e and 34 f, respectively. is doing.

  Hereinafter, a part of the incident surfaces 34a and 34b, the reflecting surface 34d, and the emitting surface 34c through which the light beam emitted from one light emitting diode of the optical member 34 passes or reflects is referred to as a light guide region for the light emitting diode. . That is, the optical member 34 of the present embodiment has three light guide regions corresponding to the three light emitting diodes.

  Here, the incident surface 34a is configured as a toric lens surface having different shapes in the vertical direction and the horizontal direction, that is, different refractive powers. Specifically, it is formed as a toric lens surface whose refractive power in the vertical direction is stronger than that in the horizontal direction. The reflecting surface 34d also has a different shape in the vertical direction and the horizontal direction.

  Of the incident surfaces 34a and 34b on which light beams emitted from the respective light emitting diodes are incident, the incident surface 34a formed at the central portion including the irradiation optical axis L is the light emitting surface of the light emitting diode when viewed from the irradiation optical axis direction. It has the same substantially circular shape. The incident surface 34a is formed as the above-described toric surface, and incident surfaces 34b formed above and below the incident surface 34a extend from the upper and lower ends of the incident surface 34a to the light emitting diode side.

  When the region surrounded by the ridge line portion on the light emitting diode side of the incident surface 34b is defined as the incident region, the incident region has the same substantially circular shape as the light emitting surface of the light emitting diode when viewed in the irradiation optical axis direction. Further, the incident area has substantially the same size as the light emitting surface of the light emitting diode. And in the state of the minimum irradiation range shown in FIGS. 19-22, the incident surface 34a is arrange | positioned in the position away from the light emission surface of the light emitting diode by the irradiation optical-axis direction length, and is a light emitting diode. The light beam emitted from the light beam is refracted and collected by the incident surface 34a. Further, the incident surface 34a is disposed on the irradiation optical axis L so as to face the light emitting surface.

  On the other hand, the incident surface 34b allows a light beam having a larger exit angle with respect to the irradiation optical axis L than a light beam incident on the incident surface 34a to exit from between the light emitting surface and the incident surface 34a. It is the 2nd entrance plane formed so that there may not be. The light beam incident from the incident surface 34b is refracted by the incident surface 34b, then totally reflected by the reflecting surface 34d, undergoes a predetermined light condensing action, and then travels to the exit surface 34c. In this way, by providing a plurality of incident surfaces according to the angle of the light beam emitted from the light emitting diode, it becomes possible to separate and independently control the light beam emitted from the light emitting diode, and to collect light efficiently. It becomes possible.

  Here, when the size of the incident region surrounded by the ridge line on the light emitting diode side of the incident surface 34b is smaller than the size of the light emitting surface of the light emitting diode, all the light beams emitted from the light emitting surface are incident on the optical member 34. Can not be made. Further, when the size of the incident region is too larger than the size of the light emitting surface, the optical member 34 is increased in size. Therefore, it is desirable to make the size of the incident region substantially equal to the light emitting surface of the light emitting diode as in this embodiment.

  Next, in this example, regarding the relationship between the shape and action of each surface in a state where the irradiation range is the narrowest (tele state), FIGS. 19 to 21 showing a vertical section and FIGS. 25 to 25 showing a horizontal section. This will be described with reference to FIG.

  The exit surface 34c of the optical member 34 is a plane substantially orthogonal to the irradiation optical axis L, as shown in FIGS. Thereby, the freedom degree in the external appearance surface of a camera can be increased.

In the cross section in the vertical direction shown in FIG. 20, the light beam emitted from each light emitting diode and incident on the incident surface 34a is directly directed to the emission surface 34c and emitted from the optical member 34 in a condensed state with the narrowest irradiation angle. . On the other hand, as shown in FIG. 21, of the light beams emitted from the respective light emitting diodes, the light beams incident from the upper and lower incident surfaces 34b are totally reflected by the reflection surface 34d and guided to the emission surface 34c.

  Here, the reflecting surface 34d is formed in a curved surface shape that becomes concave toward the irradiation optical axis L, as shown in FIGS. In addition, when the optical member 34 is cut along a plane orthogonal to the irradiation optical axis L, the reflection surface 34d continuously increases in distance from the irradiation optical axis L as the cutting position approaches the emission surface 34c. It has such a shape. In this case, as shown in FIG. 21, the light beam emitted from each light-emitting diode and reflected by the reflecting surface 34d is emitted from the optical member 34 with the irradiation angle being the narrowest.

  Further, as shown in FIG. 18, when the optical member 34 is viewed from the irradiation optical axis direction, the opening of the region (exit region) 34g through which the light flux from each light-emitting diode passes is formed on the incident surface 34a. It has a substantially elliptical shape larger than the opening. The elliptical shape has a vertical direction as a major axis direction.

  Next, the cross-sectional shape in the horizontal direction will be described with reference to FIGS. In this embodiment, as shown in FIGS. 25 to 27, the light distribution characteristics are determined by the light collection method substantially the same as that in the vertical direction. Since the shapes of the three light guide regions of the optical member 34 with respect to the three light emitting diodes 31 to 33 are the same, FIG. 26 and FIG. ing. The trace diagram of the light flux from the light emitting diodes 31 and 33 is almost the same as this. Here, for the reasons described above, reference numerals 34e and 34f are assigned to the incident surface 34b and the reflecting surface 34c, respectively.

As shown in FIG. 26, a light beam emitted from each light emitting diode and incident on the incident surface 34a is directly directed to the emission surface 34c and emitted from the optical member 34 at the narrowest irradiation angle corresponding to the necessary irradiation range. On the other hand, as shown in FIG. 27, among the light beams emitted from the respective light emitting diodes, the light beam incident from the incident surface 34e is totally reflected by the reflection surface 34f and guided to the emission surface 34c.

  Here, the reflecting surface 34f is formed in a curved surface shape that becomes concave toward the irradiation optical axis L, as shown in FIGS. Further, when the optical member 34 is cut along a plane orthogonal to the irradiation optical axis L, the reflection surface 34f continuously increases in distance from the irradiation optical axis L as the cutting position approaches the exit surface 34c. It has such a shape. These points are the same as the vertical cross section. However, the curvature of the reflecting surface 34f in the horizontal section (that is, the optical power: the reciprocal of the focal length) is larger than the curvature of the reflecting surface 34c in the vertical section.

  Also in this case, as shown in FIG. 27, the light beam emitted from each light emitting diode and reflected by the reflecting surface 34f is emitted from the optical member 34 in a state where the irradiation angle is the narrowest.

  Next, in this example, regarding the relationship between the shape and action of each surface in a state where the irradiation range is the widest (wide state), FIGS. 22 to 24 showing a vertical section and FIGS. 28 to 28 showing a horizontal section. This will be described with reference to FIG. In this wide state, the light emitting diodes 31 to 33 are moved forward toward the subject side as compared to the tele state, and the respective light emitting diodes are arranged in a space surrounded by the incident surfaces 34a and 34b of the optical member 34.

In the vertical cross section shown in FIG. 23, the light beam emitted from each light emitting diode and incident on the incident surface 34a is directly directed to the emission surface 34c and emitted from the optical member 34 with a wide irradiation angle corresponding to the required irradiation range. The On the other hand, as shown in FIG. 24, among the light beams emitted from the respective light emitting diodes, the light beam incident from the incident surface 34b is totally reflected by the reflection surface 34d and guided to the emission surface 34c. Also in this case, as shown in FIG. 24, the light beam emitted from the light-emitting diodes 31, 32, 33 and reflected by the reflecting surface 34d is directed toward the emitting surface 34c and then emitted with the widest irradiation angle.

In addition, in the horizontal cross section shown in FIG. 29, the light beam emitted from each of the light emitting diodes 31, 32, 33 and incident on the incident surface 34a is directly directed to the emission surface 34c and has the widest irradiation angle corresponding to the required irradiation range. In the state, it is ejected from the optical member 34. On the other hand, as shown in FIG. 30, among the light beams emitted from the respective light emitting diodes, the light beam incident from the incident surface 34e is totally reflected by the reflection surface 34f and guided to the emission surface 34c. Also in this case, as shown in FIG. 30, the light beam emitted from each light emitting diode and reflected by the reflecting surface 34f is converted into a light beam having the widest irradiation angle corresponding to the required irradiation range.

  As described above, according to the present embodiment, the vertical and horizontal irradiation angles can be changed simultaneously by moving the light emitting diodes 31 to 33 in the irradiation optical axis direction with respect to the optical member 34. In the present embodiment, only the case where the irradiation angle is the narrowest and the widest case has been described. However, the irradiation angle changes in a continuous or stepwise relative positional relationship between the light emitting diodes 31 to 33 and the optical member 34. Can be changed continuously or stepwise.

  For this reason, by changing the irradiation angle in conjunction with the focal length of the photographic lens of the digital camera, it is possible to perform extremely efficient illumination that finely corresponds to the imaging field angle.

  In this embodiment, an example in which three light emitting diodes are used has been described. However, in the present invention, the number of light sources is not limited to this, and may be two or four or more.

  Furthermore, in the present embodiment, an example in which the exit surface 34c of the optical member 34 is a flat surface has been shown, but a lens shape can be added to the exit surface.

  Further, in this embodiment, an example in which white light is emitted using a white light emitting diode has been described. However, the present invention is not limited to this, and, for example, blue, red, and green light emitting diodes are used and the three colors are used. It is also possible to irradiate white light by synthesizing.

  In the present embodiment, the example in which the three light emitting diodes are arranged in the horizontal direction has been described. However, the arrangement of the plurality of light sources of the present invention is not limited to this. For example, by arranging a plurality of light emitting diodes in a zigzag pattern when viewed in the direction of the irradiation optical axis, the horizontal length of the light emitting unit of the lighting device is larger than the case where the same number of light emitting diodes are arranged in a row in the horizontal direction. Can be shortened.

  In the present embodiment, the case where a plurality of light emitting diodes are collectively arranged at the corner of the digital camera main body 38 has been described. However, a plurality of light sources and optical members may be arranged at positions apart from each other. Further, a plurality of light emitting diodes may be arranged in a vertical line along the side surface of the camera.

  FIG. 31 shows a schematic configuration of a digital camera (imaging device) including an illumination device that is Embodiment 4 of the present invention. In FIG. 31, 48 is a digital camera body, 481 is a lens barrel having a photographing lens, 482 is a CCD sensor or CMOS sensor for photoelectrically converting a subject image formed by the lens barrel 481 to obtain an image, etc. This is an image sensor. The lens barrel 481 and the imaging element 482 constitute an imaging system. Reference numeral 49 denotes an illuminating device according to this embodiment that irradiates a subject with illumination light.

  As shown in FIG. 31, the illumination device of this embodiment is the front surface of the digital camera body 48, along the side surface of the digital camera body 48 at the upper right end of the lens barrel 481 when viewed from the front surface. Thus, five light emitting diodes are arranged in the vertical direction.

  This is a position that is farthest from the taking lens among the front face of the limited digital camera and is convenient for preventing the finger from being caught during photographing. By disposing the illumination device 49 at a position far from the photographing lens, it is possible to prevent the red-eye phenomenon during still image photographing.

  Even in the illumination device 49 of the present embodiment, by adopting the configuration described in the first to third embodiments, the luminous fluxes emitted from the five light emitting diodes arranged at predetermined intervals in the vertical direction can be efficiently condensed. Can do. That is, as in the first to third embodiments, a predetermined light distribution characteristic can be obtained in a necessary irradiation range by superimposing a plurality of light beams having substantially the same light distribution characteristic.

  In the said Example 3, although the illuminating device which can change an irradiation angle was demonstrated, it may be good to be able to change the direction which irradiates light.

  In general, the photographing optical axis of the photographing lens and the irradiation optical axis of the illumination device (hereinafter referred to as illumination optical axis) are in a shifted relationship. In this case, in a state where the subject is relatively far away, there is no problem even if the illumination optical axis and the photographing optical axis are parallel at a shifted position. However, when the subject is close, there is a possibility that the illumination of the subject existing on the opposite side of the illuminating device with respect to the photographing lens may be insufficient due to the deviation between the illumination optical axis and the photographing optical axis. Therefore, ideally, it is desirable that the illumination optical axis intersects with the photographing optical axis at a distance where the close subject exists. The present embodiment is for solving this problem.

  FIG. 32 shows a schematic configuration of a digital camera (imaging device) including an illumination device that is Embodiment 5 of the present invention. 32, 58 is a digital camera body, 581 is a lens barrel having a photographic lens, 582 is a CCD sensor or CMOS sensor for photoelectrically converting a subject image formed by the lens barrel 581 to obtain an image, etc. This is an image sensor. The lens barrel 581 and the imaging element 582 constitute an imaging system. Reference numeral 59 denotes an illuminating device according to the present embodiment that irradiates a subject with illumination light.

  33 and 34, the illumination device 59 is shown enlarged. In these drawings, reference numerals 51, 52, and 53 denote three light emitting diodes having a light emitting surface having a substantially circular shape, and reference numeral 54 denotes an optical member that condenses the light beams emitted from the light emitting diodes 51 to 53.

  The illumination device of the present embodiment is the front surface of the digital camera main body 58, and light emitting diodes 51 and 52 are arranged on the left and right at the upper right corner of the lens barrel 581 when viewed from the front surface. , 53 are arranged so as to be lined up and down. That is, the three light emitting diodes 51 to 53 are arranged in a substantially L shape that is upside down.

  A hard substrate 55 is electrically connected to the light emitting diodes 51 to 53 and holds the light emitting diodes 51 to 53. Further, the hard substrate 55 can move in a direction G away from the lens barrel (photographing lens) 581 in a plane substantially perpendicular to the irradiation optical axis L with respect to the optical member 54 fixed to the camera body 58. Is held in. A line F shown in FIGS. 32 to 34 is a line connecting the center of the lens barrel (photographing lens) 581 and the center of the light emitting diode 52 (irradiation optical axis L) in the front view. G is the direction along this line.

  FIG. 33 shows the positional relationship between the light emitting diode and the optical member in the case of normal photographing where the subject is relatively far away. In this case, the photographing optical axis and the illumination optical axis are parallel.

  FIG. 34 shows an ideal arrangement of the illumination optical system between the light emitting diode and the optical member in a state where the subject is located at a close distance. This state is realized by moving the hard substrate 55 in the direction G by a drive mechanism (not shown) or manually from the state of FIG.

  As described above, the light emitting diodes 51 to 53 are moved together with the hard substrate 55 in the direction G away from the photographing optical axis with respect to the optical member 54 fixed to the digital camera main body 58, so that the illumination optical system is decentered. Become. And thereby, an illumination optical axis can be made to cross | intersect with an imaging | photography optical axis at the near distance from a camera. That is, the irradiation direction can be changed.

  For example, by moving the light emitting diodes 51 to 53 in the G direction by controlling the driving mechanism according to the object distance detection information by the CPU, the irradiation direction of the illumination light is automatically changed according to the object distance. be able to. Thereby, it is possible to perform optimal illumination even for a short-distance subject.

  In the third embodiment and the present embodiment, the case where the light emitting diode moves in the irradiation optical axis direction or a direction orthogonal to the irradiation optical axis direction with respect to the fixed optical member has been described. You may move with respect to.

1 is a front view of a digital camera including an illumination device that is Embodiment 1 of the present invention. The enlarged view of the illuminating device of Example 1. FIG. FIG. 3 is a vertical sectional view of the lighting device according to the first embodiment. It is the vertical sectional view of the illuminating device of Example 1, Comprising: The figure which attached the light ray trace figure. It is the vertical sectional view of the illuminating device of Example 1, Comprising: The figure which attached the light ray trace figure. FIG. 3 is a horizontal sectional view of the lighting apparatus according to the first embodiment. It is the horizontal sectional view of the illuminating device of Example 1, Comprising: The figure which attached the light ray trace figure. It is the horizontal sectional view of the illuminating device of Example 1, Comprising: The figure which attached the light ray trace figure. The front view of the digital camera provided with the illuminating device which is Example 2 of this invention. The enlarged view of the illuminating device of Example 2. FIG. FIG. 6 is a vertical sectional view of the lighting device according to the second embodiment. It is the vertical sectional view of the illuminating device of Example 2, Comprising: The figure which added the light ray trace figure. It is the vertical sectional view of the illuminating device of Example 2, Comprising: The figure which added the light ray trace figure. The horizontal sectional view of the illuminating device of Example 2. FIG. It is the horizontal sectional view of the illuminating device of Example 2, Comprising: The figure which attached the light ray trace figure. It is the horizontal sectional view of the illuminating device of Example 2, Comprising: The figure which attached the light ray trace figure. The front view of the digital camera provided with the illuminating device which is Example 3 of this invention. The enlarged view of the illuminating device of Example 3. FIG. The vertical sectional view of the illuminating device of Example 3 (tele state). It is the vertical sectional view of the illuminating device (telephoto state) of Example 3, Comprising: The figure which attached the light ray trace figure. It is the vertical sectional view of the illuminating device (telephoto state) of Example 3, Comprising: The figure which attached the light ray trace figure. FIG. 10 is a vertical sectional view of the illumination device (wide state) according to the third embodiment. It is the vertical sectional view of the illuminating device (wide state) of Example 3, Comprising: The figure which added the light ray trace figure. It is the vertical sectional view of the illuminating device (wide state) of Example 3, Comprising: The figure which added the light ray trace figure. The horizontal sectional view of the illuminating device (telephoto state) of Example 3. It is the horizontal sectional view of the illuminating device (telestate) of Example 3, Comprising: The figure which added the light ray trace figure. It is the horizontal sectional view of the illuminating device (telestate) of Example 3, Comprising: The figure which added the light ray trace figure. The horizontal sectional view of the illuminating device (wide state) of Example 3. It is the horizontal sectional view of the illuminating device (wide state) of Example 3, Comprising: The figure which attached the light ray trace figure. It is the horizontal sectional view of the illuminating device (wide state) of Example 3, Comprising: The figure which attached the light ray trace figure. The front view of the digital camera provided with the illuminating device which is Example 4 of this invention. The front view of the digital camera provided with the illuminating device which is Example 5 of this invention. The enlarged view of the illuminating device of Example 5. FIG. The enlarged view of the illuminating device of Example 5. FIG.

Explanation of symbols

1, 2, 3, 21, 22, 23, 31, 32, 33, 51, 52, 53 Light-emitting diode 4, 24, 34, 54 Optical member 5, 25, 35, 55 Hard substrate 6, 26, 36 Exterior Member 11, 28, 38, 48, 58 Digital camera body 12, 281, 381, 481, 581 Lens barrel 13, 29, 39, 49, 59 Illumination device

Claims (4)

A light emitting unit having a plurality of light sources ;
A plurality of incident surfaces which light beams emitted from said plurality of light sources are incident, respectively, is provided so as to surround the exit surface through which the light beam incident from the plurality of the incident surface, of each of the plurality of light sources to the optical axis A reflective surface for guiding the light beam incident from the plurality of incident surfaces to the exit surface, and an optical member,
An imaging system for imaging a subject,
The vicinity of the exit surface of the region surrounded by the reflective surface of the optical member is a first direction in which the angle of view in the imaging system is narrow on a plane orthogonal to at least one of the optical axes of the plurality of light sources. Is wider than the width in the second direction orthogonal to the first direction,
The imaging apparatus according to claim 1, wherein the exit surface has a refractive power in the first direction larger than a refractive power in the second direction. The vicinity of the exit surface of the region surrounded by the reflecting surface of the optical member is a substantially elliptical shape in which the first direction is the major axis direction on a plane orthogonal to at least one of the optical axes of the plurality of light sources. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is provided. The vicinity of the exit surface of the region surrounded by the reflecting surface of the optical member is a plane perpendicular to at least one of the optical axes of the plurality of light sources , and the length in the first direction is the second direction. The imaging apparatus according to claim 1, wherein the imaging apparatus has a substantially rectangular shape longer than the length. The vicinity of the incident surface of the region surrounded by the reflecting surface of the optical member has a width in the first direction and a width in the second direction on a plane orthogonal to at least one of the optical axes of the plurality of light sources. The imaging device according to any one of claims 1 to 3, wherein and are substantially equal.