JP2007163876A - Lighting device and photographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the lighting device capable of achieving high light utilization efficiency and satisfactory light distribution characteristics using a surface light emitting solid-state element as a light source, although it is small in size. <P>SOLUTION: The lighting device 5 includes the surface light emitting solid-state element 6 having a curved surface and an optical member 7 provided with at least a reflective surface and having a light concentrating function to a light irradiation range for the light from the surface light emitting solid-state element. The lighting device 305 includes a surface light emitting solid-state element 46 having flexibility and a mechanism 50 varying the shape of the surface light emitting solid-state element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illuminating device mounted on a photographing apparatus or the like, and more particularly to an illuminating device using a surface emitting solid element such as an organic or inorganic EL (electroluminescence) element as a light source.

  In a lighting device mounted on a recent photographing apparatus such as a digital still camera, a film camera, and a video camera, it is considered to use a self-luminous surface emitting solid-state element such as an organic or inorganic EL element as a light source.

  For example, an organic EL element generally has a configuration in which an organic layer including a light emitting layer (a thin film made of an organic compound including a fluorescent organic compound) is sandwiched between electrodes of an anode and a cathode, and current is supplied between the electrodes. This is an element that emits light. Specifically, electrons and holes (holes) are injected into the organic phosphor from the outside, and light emission centers are excited by their recombination energy. In such an organic EL element, by stacking three types of light emitting layers of blue, green, and red that can emit light with high luminance (100,000 cd / m 2 or more) and high efficiency (10 lm / W or more), Bright white light can be emitted.

  Therefore, when such a thin organic EL element is used as a light source, it is possible to reduce the thickness and size of the illuminating device, and to realize a reduction in size and weight of the photographing device.

  Patent Document 1 discloses a flash apparatus that illuminates a subject by causing a large current that normally breaks in less than 1 second to flow through an organic EL element instantaneously to emit light strongly for a short time. .

The organic EL element can also be formed in a film shape whose shape is flexible. Patent Document 2 discloses an illuminating device (spotlight) in which an organic EL element is formed in a curved surface shape, and a emitted light beam is condensed at one point in front to form a virtual single point light source. In this spotlight, the light irradiation angle is made variable by changing the distance between the organic EL element and the optical member.
Japanese Patent Laying-Open No. 2004-109430 (paragraph 0018, FIG. 1, etc.) Japanese Patent Laid-Open No. 2001-307502 (paragraphs 0034 and 0028, FIG. 8B, FIG. 4 and the like)

  However, in the flash device disclosed in Patent Document 1, an optical member having a condensing function for light from the organic EL element is disposed on the front side (light irradiation side or subject side) of the organic EL element that is a light source. It has not been. For this reason, the light from the organic EL element cannot be efficiently collected in a necessary light irradiation range, and there is a possibility that desired light distribution characteristics cannot be obtained.

  In the spotlight disclosed in Patent Document 2, a plano-convex lens or a Fresnel lens is disposed as an optical member having a light condensing function on the front side of an organic EL element that is a light source. However, since the light which does not enter the optical member among the light emitted from each light emitting point on the organic EL element in a diffused state cannot be used, it cannot be said that the lighting device has sufficiently high light use efficiency. In addition, in the configuration in which the light irradiation angle is changed by changing the distance between the organic EL element and the optical member, it is necessary to greatly change the distance with respect to the amount of change in the irradiation angle, which increases the size of the apparatus. There is.

  An object of the present invention is to provide an illumination device that uses a surface-emitting solid-state element as a light source and is small in size, and that can obtain high light use efficiency and good light distribution characteristics. Another object of the present invention is to provide an illumination device that uses a surface-emitting solid-state element as a light source and can change the irradiation angle while being small.

  An illuminating device according to one aspect of the first invention of the present application includes a surface-emitting solid element having a curved shape, and at least a reflecting surface, and has an optical function of condensing light from the surface-emitting solid element into a light irradiation range. And a member.

  An illumination device according to another aspect of the second invention of the present application includes a flexible surface-emitting solid element and a mechanism for changing the shape of the surface-emitting solid element.

  In addition, the imaging device provided with each said illuminating device also comprises the other side surface of this invention.

  According to the first aspect of the present invention, light from a surface-emitting solid element having a curved surface shape is irradiated onto a light irradiation range in a condensed state by an optical member having at least a reflective surface, so that the light use efficiency is high and desired. It is possible to realize a small illuminating device that can achieve the light distribution characteristics described above.

  In addition, according to the second invention, by providing a mechanism for changing the shape of the surface emitting solid element, it is possible to realize a small illumination device capable of changing the irradiation angle with almost no change in the position of the surface emitting solid element.

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

  FIG. 1 shows the configuration of a digital still camera equipped with an illumination apparatus that is Embodiment 1 of the present invention. Reference numeral 1 denotes a camera body. Reference numeral 2 denotes a photographing lens barrel, which holds a photographing lens (not shown).

  An optical viewfinder 3 is used by a photographer to observe a subject when determining a composition. Reference numeral 4 denotes a release button. This camera incorporates an image pickup device (not shown) constituted by a CCD sensor, a CMOS sensor, or the like that photoelectrically converts a subject image formed by a photographing lens.

  Reference numeral 5 denotes an illumination device, which is built in the upper right part of the camera body 1. As will be described later, the illumination device of this example uses a surface emitting solid element (sometimes referred to as an electric field solid surface light emitting element) such as an organic EL element or an inorganic EL element as a light source, and further emits the surface light. An optical member that efficiently collects light from the solid state element is used. A surface-emitting solid element emits light from almost the entire light-emitting surface, and is different from a point light source such as a lamp or a linear light source such as a discharge tube.

  In this embodiment, a digital still camera will be described. However, the lighting device of the present invention is not limited to this, and can be applied to a lighting device of a film camera or a video camera.

  Next, the structure of the organic EL element will be described with reference to FIG. FIG. 2 schematically shows a basic configuration of the organic EL element.

  The organic EL element 6 is formed by laminating a transparent electrode (anode) 11, an organic layer (organic compound thin film) 12 including a light emitting layer, and a reflective electrode (cathode) 13 in this order on a transparent substrate 10 formed of glass or the like. The configuration is as follows.

  The transparent substrate 10 is a transparent substrate having a light transmittance of 70% or more such as glass or plastic, and is formed as a solid substrate such as glass or quartz. Moreover, it is good also considering the transparent substrate 10 as a flexible substrate using the following materials. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide (PEI), polyetheretherketone (PEEK), and polyphenylene sulfide (PPS) can be used. Furthermore, polyarylate (PAR), polyimide (PI), polycycloolefin (PCO), polycarbonate (PC), cellulose triacetate (CTA), and cellulose acetate propionate (CAP) can also be used.

  The transparent electrode 11 is formed of a conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), gold, tin oxide, or zinc oxide. It is preferable to use a material having a work function of 4 eV or more and a light transmittance of 60% or more.

  The organic layer 12 is composed of a single layer or a plurality of layers of an organic compound or complex of several nm to μm including the light emitting layer. A lithium fluoride layer, an inorganic metal salt layer, or a layer containing them may be disposed at an arbitrary position.

  The reflective electrode 13 is formed of a metal material such as aluminum, sodium, lithium, magnesium, silver, or calcium. It is preferable to use a material having a work function of less than 4 eV and a reflectance of 70% or more.

  The organic EL element 6 is derived from fluorescence or phosphorescence because electrons and holes are combined in one or more light-emitting layers constituting the organic layer 12 by the current supplied from the power supply 15 to the transparent electrode 11 and the reflective electrode 13. Flashes.

  In the organic EL element 6 of the present embodiment, the transparent electrode 11 and the reflective electrode 13 have a form as a common electrode that is electrically connected on either side thereof. However, the form of the electrode corresponding to each organic layer may be adopted. In any of these forms, the transparent electrode 11 and the reflective electrode 13 are treated as being laminated with an organic layer interposed therebetween. This is the same in other embodiments described later.

  The organic EL element 6 may have a top emission structure in which the positions of the transparent electrode 11 and the reflective electrode 13 are interchanged.

  In addition, since organic compounds are severely deteriorated by moisture and oxygen in the atmosphere, the organic layer 12 is covered and sealed on the transparent substrate 10 using a metal tube, a glass tube or the like in an inert gas atmosphere such as nitrogen. Stop and shield from the outside atmosphere. However, in FIG. 2, the sealing film is omitted.

  Next, the structure and optical action of the illumination device 5 of the present embodiment will be described with reference to FIGS.

  3 is a perspective view showing main parts of the lighting device 5 as viewed from the front (light irradiation range side or subject side), and FIG. 4 is an exploded perspective view showing the main parts of the lighting device 5 as seen from the front. It is. In these figures, lead members connected to the holding members and organic EL elements for holding the main components are not shown. This also applies to the drawings of other embodiments described below.

  As shown in FIGS. 3 and 4, the organic EL element 6 and the optical member 7 of the present example each have a longitudinal direction in a direction (horizontal direction) orthogonal to the irradiation optical axis AXL of the illumination device 5. It has a rectangular shape when viewed from the object side. The irradiation optical axis AXL is a virtual axis extending from the center of the light emitting surface of the organic EL element 6 through the center of the incident surface 7a and the exit surface 7c of the optical member 7.

  The organic EL element 6 has a curved surface shape that is concave toward the front. The organic EL element 6 receives power supplied from an electric circuit (not shown) and emits light for a short time of 1 μs or more and 100 μs or less.

  In the present embodiment, a plastic film having a flexible structure is used as the organic EL element 6 as the transparent substrate 10, and high luminance white light is emitted by stacking three light emitting layers of blue, green, and red. In addition, you may employ | adopt the form which whitens by making light emission wavelength of the organic layer 12 pinched | interposed between two electrodes emit light simultaneously as two types of blue and yellow light emitting layers, for example. These are the same in other embodiments described later.

  The optical member 7 is disposed in front of the organic EL element 6 and directly takes the light emitted from the organic EL element 6 and condenses it into a predetermined shape, and efficiently irradiates the light irradiation range necessary for photographing. In other words, the light emitted from the organic EL element 6 has a condensing action on the light irradiation range, and the light distribution in the light irradiation range is controlled by this action. When a discharge tube or the like is used as a light source, a reflector having a condensing function for returning light emitted backward from the light source to the light source is unnecessary. The optical member 7 is formed of an optical resin material or glass material having a high transmittance such as a light acrylic resin.

  Here, by making the organic EL element 6 having a flexible structure into a curved shape, the apparent area of the organic EL element 6 as a light source can be reduced. For this reason, when the illumination device 5 is viewed from the front, the projection area of the illumination device 5 can also be reduced. Therefore, when the illumination device 5 is mounted on the camera, there is an advantage that the degree of freedom in designing the camera is increased.

  For example, when the camera equipped with the illumination device 5 is set to “strobe auto mode” and the release button 4 is half-pressed by the user, the brightness of external light (subject) is measured by a photometric unit (not shown). Is measured. The photometric result is sent to a central processing unit (not shown) arranged in the camera body 1. The central processing unit determines whether or not the illumination device 5 is caused to emit light based on the photometric result and the sensitivity of the image sensor (film in the case of a film camera).

  When it is determined that “the illumination device is to emit light”, the central processing unit outputs a light emission signal to the illumination device 5 in response to the full pressing operation of the release button 4, and the organic EL element 6 emits light in response thereto. To do.

  The light emitted from the organic EL element 6 directly enters the optical member 7 from the incident surface 7a of the optical member 7, is converted into light having a predetermined light distribution characteristic, and is then irradiated on the subject side.

  FIG. 5 is a cross-sectional view of the illumination device 5 cut along the irradiation optical axis AXL. In FIG. 5, a trace diagram of light rays emitted from the vicinity of the center of the organic EL element 6 is added.

  As shown in the figure, for the organic EL element 6 having a curved shape that is concave on the subject side, the optical member 7 is a curved surface that follows the curved shape of the organic EL element 6, that is, is concave toward the subject side. It has a shaped incident surface 7a. The incident surface 7a of the optical member 7 is disposed close to the organic EL element 6 so that almost all of the light emitted from each light emitting point of the organic EL element 6 is incident on the incident surface 7a. Note that the light utilization efficiency increases as they approach each other, but it is desirable that the distance be 0.2 mm or more away from physical conditions.

  As can be seen from the ray trace diagram shown in FIG. 5, the light beam emitted from the vicinity of the center of the organic EL element 6 receives a condensing action by its positive refractive power from the incident surface 7a. Of the light beam refracted on the incident surface 7a, the light beam component traveling at an angle smaller than the predetermined angle θ with respect to the irradiation optical axis AXL is directly emitted from the emission surface 7c. In addition, the luminous flux component that has advanced at an angle larger than the predetermined angle θ with respect to the irradiation optical axis AXL among the luminous flux refracted on the incident surface 7a is reflected by the reflecting surface 7b and then emitted from the emitting surface 7c.

  The reflecting surface 7b is formed as a flat surface or a gently curved surface that is inclined in a direction that spreads with respect to the irradiation optical axis AXL toward the exit surface 7c. The exit surface 7c has a shape that is convex toward the subject side, and mainly has an action of refracting the light beam reflected by the reflecting surface 7b more toward the irradiation optical axis AXL.

  The optical member 7 has an effect of efficiently converting a light beam emitted from the organic EL element 6 into a light beam condensed on the subject side by the incident surface 7a, the reflection surface 7b, and the emission surface 7c.

  In the present embodiment, the incident surface 7a of the optical member 7 is a curved surface having a positive refractive power, but the optical member in the present invention is not limited to this. For example, as shown in FIG. 6, the incident surface 7a 'may be formed as a flat surface. Furthermore, each surface of the optical member 7 may have any shape as long as the light beam finally emitted from the optical member 7 is converted into a light beam that converges toward a desired light irradiation range.

  FIG. 7 shows a trace diagram of light rays emitted from the peripheral portion of the organic EL element 6 in the same cross section as FIG.

  In FIG. 7, the main traveling direction of a light beam emitted from the peripheral portion of the organic EL element 6 is directed to one point on the irradiation optical axis AXL. This is the direction in which the light easily enters the incident surface 7a of the optical member 7. Therefore, more light beams emitted from the curved organic EL element 6 are incident on the incident surface 7 a of the optical member 7 than the planar organic EL element. Thereby, the illuminating device 5 with high utilization efficiency of light is realizable.

  8 to 11 show the configuration of a lighting apparatus that is Embodiment 2 of the present invention. The illumination device of the present embodiment is also mounted on the camera shown in FIG.

  FIG. 8 is a perspective view in an assembled state showing main parts of the lighting device 105 of the present embodiment as seen from the front, and FIG. 9 is an exploded perspective view showing main parts of the lighting device 105 as seen from the front. is there. In these drawings, a holding member and a lead wire for holding each main part are omitted.

  As shown in FIGS. 8 and 9, the organic EL element 26 and the optical member 27 of the present embodiment each have a longitudinal direction in the direction (horizontal direction) orthogonal to the irradiation optical axis AXL of the illumination device 105. It has a rectangular shape when viewed from the object side.

  The organic EL element 26 has a curved surface shape that protrudes forward. The organic EL element 26 receives power supplied from an electric circuit (not shown) and emits light for a short time of 1 μs or more and 100 μs or less.

  The optical member 27 is disposed in front of the organic EL element 26, directly takes in the light emitted from the organic EL element 26, condenses it into a predetermined shape, and efficiently irradiates the light irradiation range necessary for photographing. In other words, the light emitted from the organic EL element 26 has a condensing action on the light irradiation range, and the light distribution in the light irradiation range is controlled by this action. Also in this embodiment, there is no need for a reflector having a condensing function for returning light emitted backward from the light source to the light source. The optical member 27 is made of an optical resin material or glass material having a high transmittance such as a light acrylic resin.

  Here, by making the organic EL element 26 having a flexible structure into a curved shape, the apparent area of the organic EL element 26 as a light source can be reduced. For this reason, when the illuminating device 105 is seen from the front, the projection area of the illuminating device 105 can also be made small. Therefore, there is an advantage that the degree of freedom in designing the camera is increased when the illumination device 105 is mounted on the camera.

  In general, as shown in FIG. 10A, in the organic EL element 20 configured on a flat surface such as glass, the light emission direction of the principal ray is parallel to the irradiation optical axis AXL. On the other hand, as shown in FIG. 10B, the organic EL element 21 having a flexible structure using a plastic film as a substrate has a curved shape that is concave toward the subject side, thereby irradiating the emission direction of the principal ray. It can be directed to one point on the optical axis AXL. Thereby, a virtual single point light source can be formed (see Patent Document 2). On the other hand, in the illumination device 105 of the present embodiment, the organic EL element 26 is formed in a curved shape that is convex toward the subject side so that the chief ray is emitted in the diverging direction. The principal ray referred to here is a ray emitted in a direction perpendicular to the light emitting surface of the organic EL element.

  FIG. 11 is a cross-sectional view of the illumination device 105 of the present embodiment cut along the irradiation optical axis AXL. Further, in FIG. 11, a trace diagram of chief rays emitted from the organic EL element 26 is appended.

  The optical member 27 includes a first incident surface 27R having a curved shape that is convex in a direction opposite to the convex shape of the organic EL element 26 (concave on the subject side), and above and below the first incident surface 27R. And a second incident surface 27C having a planar shape.

  As can be seen from the ray trace diagram, the chief ray emitted from the organic EL element at an angle smaller than the first angle θ1 with respect to the irradiation optical axis AXL is the first incident of the optical member 27. Incident on the surface 27R. These principal rays receive positive refracting power from the first incident surface 27R, become rays substantially parallel to the irradiation optical axis AXL, and are emitted from the emission surface 27H having a planar shape as it is. The first incident surface 27R is preferably formed as a hyperboloid.

  Further, among the principal rays emitted from the organic EL element, the principal ray emitted at an angle larger than the first angle θ1 with respect to the irradiation optical axis AXL is incident on the second incident surface 27C of the optical member 27. These chief rays are refracted by the second incident surface 27C and travel toward the reflecting surface 27TR. Then, the light is substantially totally reflected by the reflecting surface 27TR, so that a light beam substantially parallel to the irradiation optical axis AXL is emitted as it is from the emitting surface 27H. Here, the principal ray refracted by the second incident surface 27C is bent in a direction in which the incident angle with respect to the reflective surface 27TR becomes smaller (a direction close to vertical), so the size of the reflective surface 27TR, that is, the optical member 27 Can be reduced.

  The shape of the reflection surface 27TR is a paraboloid or a cylindrical aspheric shape close to the paraboloid so that most of the incident light rays are totally reflected and the parallelism of the light rays after reflection is good. Is preferred.

  The optical member 27 has an effect of efficiently converting all the light beams emitted from the organic EL element 26 into parallel light beams that are condensed on the subject side by the incident surfaces 27R and 27C and the reflection surface 27TR. In particular, since the light emitted from the organic EL element 26 at a large angle with respect to the irradiation optical axis AXL is also effectively used, an illumination device with high light use efficiency can be obtained.

  In the present embodiment, the case where the shape of the optical member 27 is set so as to emit a parallel light beam has been described. However, as shown in FIG. 12, the position of the organic EL element 26 and the shapes of the first and second incident surfaces 27R and 27C of the optical member 27 ′ and the shape of the reflecting surface 27TR are different from those of the present embodiment. The directivity characteristic of the emitted light beam can be arbitrarily set.

  13 and 14 show the configuration of a lighting apparatus that is Embodiment 3 of the present invention. The illumination device of the present embodiment is also mounted on the camera shown in FIG.

  FIG. 13 is a perspective view in an assembled state showing the main components of the illumination device 205 of this embodiment as seen from the front. In FIG. 13, a holding member and a lead wire for holding each main part are omitted.

  In the first and second embodiments, the case where the optical member having the incident surface, the reflection surface, and the emission surface is arranged in front of the organic EL element has been described. However, in this embodiment, the rear of the organic EL element 36 (light A reflection member (optical member) 37 is disposed on the side opposite to the irradiation range or the subject side.

  As shown in FIG. 13, the organic EL element 36 and the reflecting member 37 of this embodiment are each viewed from the subject side, with the direction (horizontal direction) orthogonal to the irradiation optical axis AXL of the illumination device 205 as the longitudinal direction. It has a rectangular shape when viewed from the front.

  The organic EL element 36 has a curved surface shape that is concave forward. The organic EL element 36 receives electric power supplied from an electric circuit (not shown) and emits light for a short time of 1 μs or more and 100 μs or less.

  The reflection member 37 is disposed rearward with respect to the organic EL element 36, reflects the light beam emitted rearward from the organic EL element 36 to the front, condenses it into a predetermined shape, and is efficient in the light irradiation range necessary for photographing. Irradiate well. In other words, the light emitted from the organic EL element 36 has a condensing action on the light irradiation range, and the light distribution in the light irradiation range is controlled by this action. The reflecting member 37 has a curvature in a one-dimensional direction, and is configured as a reflecting mirror using metal internal reflection.

  FIG. 14 is a cross-sectional view of the illumination device 205 according to the present embodiment cut along the irradiation optical axis AXL. Further, in FIG. 14, a trace diagram of chief rays emitted from the organic EL element 36 is appended.

  The reflective member 37 has a curved surface shape that is concave in the same direction as the concave shape of the organic EL element 36 (concave toward the front).

  The reflection surface of the reflection member 37 is formed as a paraboloid. The virtual light emission point of the principal ray emitted from the organic EL element 36 substantially coincides with the focal point of the paraboloid of the reflecting member 37. With such a shape, all the chief rays emitted from the organic EL element 36 are reflected by the reflecting member 37 and emitted to the subject side as a parallel light beam.

  The reflecting member 37 has an effect of converting the light beam emitted from the organic EL element 36 into a light beam that is efficiently condensed on the subject side by the reflection surface. Further, by making all the principal rays emitted from the organic EL element 36 into parallel luminous fluxes, the light distribution characteristics can be set in a narrow angle range.

  Of the principal rays emitted from the organic EL element 36, the principal ray directed toward the reflecting member 37 at a small angle with respect to the irradiation optical axis AXL is reflected by the reflecting member 37 and then returns to the organic EL element 36 again. Then, the light is reflected from the reflective electrode 13 of the organic EL element 36 and emitted from the organic EL element 36, and travels toward the reflective member 37. At this time or while repeating this, the angle with respect to the irradiation optical axis AXL is increased and finally emitted toward the subject side. Therefore, it can be set as the illuminating device with high light utilization efficiency.

  In the present embodiment, the light beam reflected by the reflecting member 37 is described as a parallel light beam. However, by changing the positional relationship between the organic EL element and the reflecting member and the reflecting surface shape of the reflecting member to an elliptical shape or the like. The directivity characteristic of the emitted light beam can be arbitrarily set.

  15 to 17 show the configuration of a lighting apparatus that is Embodiment 4 of the present invention. The illumination device of the present embodiment is also mounted on the camera shown in FIG.

  FIG. 15 is a perspective view in an assembled state showing the main components of the illumination device 305 of the present embodiment as viewed from the front. In this figure, holding members and lead wires for holding the main parts are omitted.

  As shown in FIG. 15, the organic EL element 46 and the optical member 47 of the present embodiment are each viewed from the subject side, with the direction perpendicular to the irradiation optical axis AXL (horizontal direction) of the illumination device 305 as the longitudinal direction. It has a rectangular shape when viewed from the front.

  The organic EL element 46 changes its shape between a curved shape that is concave forward and a planar shape by using its flexible structure. The organic EL element 46 receives power supplied from an electric circuit (not shown) and emits light for a short time of 1 μs to 100 μs.

  The optical member 47 is disposed in front of the organic EL element 46, directly takes in the light emitted from the organic EL element 46, condenses it into a predetermined shape, and efficiently irradiates the light irradiation range necessary for photographing. In the present embodiment, the change in the shape of the organic EL element 46 and the interaction with the optical member 47 having a condensing effect on the light irradiation range with respect to the light emitted from the organic EL element 46 are performed in the light irradiation range. Control the light distribution.

  Also in the present embodiment, as in the first and second embodiments, a reflector having a condensing function for returning the light emitted backward from the light source to the light source is unnecessary. The optical member 47 is formed of an optical resin material having a high transmittance such as a light acrylic resin.

  In this embodiment, the optical member 47 is formed as a Fresnel lens. The Fresnel lens is obtained by dividing the curved surface of a plano-convex lens and gathering them on a plane, and can be formed lighter than a plano-convex lens. In addition, the optical member 47 of a present Example does not have a reflective surface like the said Examples 1-3.

  FIGS. 16A and 16B are cross-sectional views of the illumination device 305 of the present embodiment cut along the irradiation optical axis AXL. FIGS. 16A and 16B also include trace diagrams of chief rays emitted from the peripheral portion of the organic EL element 46.

  FIG. 16A shows a case where the organic EL element 46 has a curved shape that is concave toward the subject, and the emitted light beam from the illumination device 305 is most condensed. FIG. 16B shows the case where the organic EL element 46 has a planar shape, and the emitted light beam from the illumination device 305 is most diverged.

  In the state of FIG. 16A, the principal ray emitted from the organic EL element 46 having a concave curved surface shape is condensed at a specific focal point of the optical member 47 as a Fresnel lens to form a virtual single point light source. The optical member 47 irradiates the subject side in a state of being condensed into a light beam substantially parallel to the irradiation optical axis AXL.

  On the other hand, in the state of FIG. 16B, a principal ray substantially parallel to the irradiation optical axis AXL is emitted from the planar organic EL element 46. For this reason, the principal ray does not form a virtual single point light source, but is once converged on the irradiation optical axis AXL by the action of the optical member 47 and then irradiated to the subject side as a divergent light beam.

  Thus, in this embodiment, the directivity characteristic (irradiation angle range) of the light emitted from the illumination device 305 can be arbitrarily changed by controlling the shape of the organic EL element 46.

  The vertical height of the optical member 47 is not related to the shape of the organic EL element 46 (that is, the height in FIG. 16B is maximized even in the state of FIG. 16A where the height is minimized). In the state) is sufficiently larger than the height of the organic EL element 46. As a result, all divergent rays other than the principal ray emitted from the organic EL element 46 also enter the optical member 47 and are condensed. Therefore, it can be set as the illuminating device with high light utilization efficiency.

  FIG. 17 shows a configuration of a mechanism for changing the shape of the organic EL element 46. FIG. 17A shows the state of the mechanism when the organic EL element 46 is curved, and FIG. 17B shows the state of the mechanism when the organic EL element 46 is planar. .

  In this figure, a pin 46 a provided at the center of the organic EL element 46 engages with a rectilinear groove 50 a formed at the center of the cam plate 50 and is fixed to a fixed frame (not shown). Further, pins 46 b and 46 c provided at both ends of the organic EL element 46 are engaged with cam grooves 50 b and 50 c formed at both ends of the cam plate 50.

  When the cam plate 50 moves in the left-right direction in the figure, both end portions of the organic EL element 46 with the center portion fixed move left and right by the action of the cam grooves 50b, 50c accompanying the movement of the cam plate 50. Thereby, the organic EL element 46 is deformed between a curved surface shape and a planar shape.

  Note that the mechanism shown in FIG. 17 is merely an example, and any mechanism may be used as long as the organic EL element is deformed between a curved surface shape and a planar shape.

  In each of the above-described embodiments, the case where the organic EL element and the optical member are formed to be rectangular in front view has been described. However, the organic EL element and the optical member may be formed in a rotationally symmetrical shape with the irradiation optical axis AXL as the center.

  In each of the above-described embodiments, a case has been described in which a current is passed through the organic EL element for a short time of 1 μs or more and 100 μs or less to emit an instantaneous flash for still image shooting. However, it is also possible to configure so that steady light is emitted for a long time by energizing for a long time at a lower voltage than when short-time energization during moving image shooting by a video camera or the like.

  Further, in each of the embodiments described above, the lighting device suitable for mounting on the photographing device has been described. However, the lighting device of the present invention can be applied to indoor lighting, a backlight of a liquid crystal display device, and the like.

  It should be noted that the dimensions, materials, shapes, relative arrangements, and the like of the components shown in the embodiments are merely examples, and the present invention is not limited to these.

1 is a perspective view of a camera equipped with a lighting device that is Embodiment 1 of the present invention. FIG. The schematic diagram for demonstrating the fundamental structure of an organic EL element. 1 is a perspective view of a lighting device according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view of the lighting device according to the first embodiment. FIG. 3 is a cross-sectional view of the lighting device of the first embodiment. Sectional drawing which shows the modification of the illuminating device of Example 1. FIG. Sectional drawing of the illuminating device of Example 1, and the trace figure of the light ray emitted from the peripheral part of the organic EL element. The perspective view of the illuminating device which is Example 2 of this invention. FIG. 6 is an exploded perspective view of a lighting device according to a second embodiment. The schematic diagram which shows the shape of an organic EL element, and the mode of the emitted light. Sectional drawing of the illuminating device of Example 2, and the trace figure of the light ray emitted from the organic EL element. Sectional drawing which shows the modification of the illuminating device of Example 2, and the trace figure of the light ray emitted from the organic EL element. The perspective view of the illuminating device which is Example 3 of this invention. Sectional drawing of the illuminating device of Example 3, and the trace figure of the light ray emitted from the organic EL element. The perspective view of the illuminating device which is Example 4 of this invention. Sectional drawing of the illuminating device of Example 4, and the trace figure of the light ray emitted from the organic EL element. FIG. 6 is a schematic view of a mechanism for deforming an organic EL element in Example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 2 Shooting lens barrel 3 Viewfinder 4 Release button 5,105,205,305 Illumination device 6,20,26,36,46 Organic EL element 7,27,37,47 Optical member 10 Transparent substrate 11 Transparent electrode 12 Organic layer 13 Reflective electrode 50 Cam plate

Claims (10)

A surface-emitting solid element having a curved shape;
An illuminating device comprising: an optical member having at least a reflective surface and having a light condensing effect on a light irradiation range with respect to light from the surface-emitting solid-state element.   The lighting device according to claim 1, wherein the surface-emitting solid element has a curved shape that is concave toward a light irradiation range.   The lighting device according to claim 1, wherein the surface-emitting solid element has a curved shape that is convex toward a light irradiation range.   The optical member includes an incident surface, a reflective surface that reflects light from the incident surface, and an exit surface that emits light from the incident surface and the reflective surface. The lighting device according to any one of the above.   The optical member includes a first incident surface on which light emitted from the surface-emitting solid element at an angle smaller than a first angle with respect to an irradiation optical axis of the illumination device is incident, and is larger than the first angle. A second incident surface on which light emitted at an angle is incident; a reflecting surface that reflects light from the second incident surface; and light from the first incident surface and light from the reflecting surface are emitted. The illumination device according to claim 3, further comprising: an exit surface.   The illumination according to claim 3, wherein the optical member is a reflecting member that reflects light emitted from the surface-emitting solid element in a direction opposite to the light irradiation range toward the light irradiation range. apparatus. A flexible surface emitting solid-state device;
And a mechanism for changing the shape of the surface-emitting solid-state element.   The illuminating device according to claim 7, further comprising an optical member having a condensing effect on a light irradiation range with respect to light from the surface-emitting solid element.   The lighting device according to claim 7, wherein the optical member is larger than the surface-emitting solid element regardless of the shape of the surface-emitting solid element.   An imaging device comprising the illumination device according to any one of claims 1 to 9.