WO2014006782A1

WO2014006782A1 - Lighting device, lighting device for photography and photography system

Info

Publication number: WO2014006782A1
Application number: PCT/JP2012/083899
Authority: WO
Inventors: 敬市川; 川口　浩司
Original assignee: 株式会社タムロン
Priority date: 2012-07-05
Filing date: 2012-12-27
Publication date: 2014-01-09
Also published as: JP2014013357A

Abstract

The present invention addresses the problem of providing: a lighting device that enables the modifiable range of a light distribution range (i.e., flash coverage) to be optically expanded as compared with the prior art, without the device configuration becoming complex or large; a lighting device for photography; and a photography system. In order to solve this problem, the present invention involves a lighting device (10) or a lighting device for photography (101) that is provided with light source (11) and an optical lens (13) having a prescribed refractive power, and emits light projected from the light source (11) via the optical lens (13). The present invention is characterized in that a variable focus lens (12) wherein the focus position can be changed with the lens position in a fixed state is provided between the light source (11) and the optical lens (13), and light projected from the light source (11) is made enter the optical lens (13) via the variable focus lens (12).

Description

Illumination device, imaging illumination device, and imaging system

The present invention relates to an illumination device, an imaging illumination device, and an imaging system, and more particularly, to an illumination device, an imaging illumination device, and an imaging system that can change an illumination range.

Conventionally, an illumination device (or an imaging illumination device) that includes a light source and an optical lens and emits light emitted from the light source via the optical lens is known. In such an illuminating device, by changing the distance between the light source and the optical lens, the focal length of the light emitted from the light source can be changed to change the light distribution angle (illumination range). (For example, refer to “Patent Document 1”). According to the illuminating device described in Patent Document 1, it is possible to irradiate by changing the light distribution angle of the light emitted from the light source to a narrow angle or a wide angle according to a required illumination effect.

In recent years, in this type of lighting device, it has been proposed to use a liquid lens called a so-called variable focus lens instead of an optical lens (see, for example, “Patent Document 2”). The curvature of the liquid lens can be changed by applying a voltage or the like. By adopting the liquid lens, the focal length of the liquid lens can be changed within a certain range without moving the position of the liquid lens. For this reason, in the illuminating device described in Patent Document 2, it is not necessary to provide a movement control mechanism for moving and controlling (driving control) the position of the liquid lens, and the apparatus can be downsized.

JP 2004-355934 A JP 2009-54491 A

However, in the liquid lens, the curvature can be changed by controlling the voltage value to be applied, but the range in which the curvature can be changed is limited to a certain limit. For this reason, the range in which the light distribution angle of the light from the light source can be changed is limited to a certain range, and the light distribution angle is made wider or narrower than the liquid lens focal length variable range. Could not change. For this reason, it is necessary to perform optical design individually according to the light distribution angle required for each lighting device, and it is difficult to share components such as a liquid lens. On the other hand, if the distance between the light source and the lens is changed as in the illumination device described in Patent Document 1, the range of the focal length can be changed as compared with the case where the position of the liquid lens is fixed. Expand to. However, in this case, similarly to the illumination device described in Patent Document 1, a movement control mechanism for moving the lens is required, which causes a problem that the device configuration becomes complicated and the device becomes larger. .

Accordingly, an object of the present invention is to provide an illuminating device and an imaging device capable of optically expanding a range in which the light distribution angle (irradiation range) can be changed as compared with the conventional one without complicating and increasing the size of the device configuration It is providing the illuminating device for imaging and an imaging system.

Thus, as a result of intensive studies, the present inventors have solved the above problems by adopting the following configuration.

An illumination device according to the present invention includes a light source and an optical lens unit having a predetermined refractive power, and emits light emitted from the light source through the optical lens unit, the light source, A variable focus lens unit capable of changing a focal length with a lens position fixed is provided between the optical lens unit and the light irradiated from the light source to the optical lens unit via the variable focus lens unit. It is made to enter.

In the illumination device according to the present invention, it is preferable that the variable focus lens unit is a liquid lens that changes a focal length based on a focus position change signal input from the outside.

In the illumination device according to the present invention, it is preferable that the focal position change signal is information regarding an imaging range input from the imaging device.

The imaging illuminating device according to the present invention is an imaging illuminating device that irradiates light in an imaging region by the above-described illumination device, and is characterized in that the illumination range in the imaging region can be changed.

An imaging system according to the present invention includes a light source and an optical lens unit having a predetermined refractive power, an illumination device that emits light emitted from the light source through the optical lens unit, and imaging within a predetermined imaging region. An imaging system including an imaging device capable of changing a range, wherein the illumination device can change a focal length between the light source and the optical lens unit with a lens position fixed. A focal length of light incident on the variable focus lens unit based on a variable focus lens unit, an input unit to which information on the imaging range is input from the imaging device, and information on the imaging range input from the input unit And a control unit that controls to change.

According to the present invention, the light emitted from the light source can be incident on the optical lens unit via the variable focus lens unit. Thereby, the light emitted from the variable focus lens unit is refracted at a predetermined refractive index by the optical lens unit. For this reason, the changeable range of the focal length (focal position) in the variable focus lens unit can be optically expanded by the optical lens unit. Thus, according to the present invention, the focal length can be changed in a wider range than the changeable range of the focal length of the variable focus lens unit without changing the separation distance of the variable focus lens unit with respect to the light source. Therefore, according to the present invention, the range in which the light distribution angle (irradiation range) can be changed can be optically expanded as compared with the conventional one without complicating and increasing the size of the apparatus. Can be diffused to a wider range or converged to a narrower range. In addition, even when the requirements regarding the light distribution angles for the individual illumination devices are different, the liquid lens or the like constituting the variable focus lens unit can be used as a common component. For this reason, for example, when used as an illumination device for imaging, it is possible to realize a light distribution angle corresponding to the angle of view of a captured image, such as a wide-angle system or a telephoto system, with a single liquid lens.

It is a block diagram which shows an example of a functional structure of the illuminating device (imaging illuminating device) which concerns on this invention. It is a schematic diagram which shows an example of a liquid lens. It is a block diagram which shows an example of a functional structure of the imaging system which concerns on this invention. It is a schematic diagram which shows the specific structural example (Example 1) of the illuminating device which concerns on this invention. It is a schematic diagram which shows the specific structural example (Example 2) of the illuminating device which concerns on this invention. It is a schematic diagram which shows the specific structural example (Example 3) of the illuminating device which concerns on this invention. It is a schematic diagram which shows the specific structural example (Example 4) of the illuminating device which concerns on this invention. It is a schematic diagram which shows the specific structural example (Example 5) of the illuminating device for imaging which concerns on this invention, and an imaging system. It is a schematic diagram which shows the structural example of the illuminating device of the comparative example 1. FIG. 10 is a schematic diagram illustrating a configuration example of a lighting device of Comparative Example 2. FIG.

Hereinafter, preferred embodiments of an illumination device and an imaging illumination device according to the present invention will be described with reference to the drawings. First, an embodiment of a lighting device will be described.

1. Illumination device 10
An example of a functional configuration of the illumination device 10 according to the present invention is shown in FIG. As shown in FIG. 1, the illumination device 10 according to the present embodiment includes a light source 11 and an optical lens unit 13, and is configured to emit light emitted from the light source 11 through the optical lens unit 13. ing. In the illuminating device 10, a variable focus lens unit 12 that can change the focal length of incident light with the lens position fixed is provided between the light source 11 and the optical lens unit 13. The light is incident on the optical lens unit 13 through the variable focus lens unit 12. That is, in the illuminating device 10 according to the present invention, the variable focus lens unit 12 and the optical lens unit 13 are arranged along the optical axis (optical path) of the irradiation light from the light source 11, and the emitted light from the light source 11 is Incident light enters the focus variable lens unit 12 and the optical lens unit 13 in this order. Further, as shown in FIG. 1, the illumination device 10 of the present embodiment has a focal position as a control system element 10b for electrically controlling the variable focus lens unit 12 in addition to these optical system elements 10a. A change signal input unit 14 and a control unit 15 are provided. Hereinafter, after describing the optical system element 10a, the control system element 10b will be described.

1-1. Optical system element 10a
(1) Light source 11
The light source 11 shown in FIG. 1 is not particularly limited as long as it can be used as the light source 11 of the lighting device 10, and in addition to a light emitting element such as a light emitting diode and an organic EL element, an incandescent bulb, a halogen bulb, and a fluorescent bulb. A conventionally known light source 11 such as a lamp can be used. These may be point light sources or surface light sources. Further, both the point light source and the surface light source can be configured using a plurality of light emitting elements and the like. These can select the suitable light source 11 suitably according to the use of the said illuminating device 10. FIG.

(2) Variable focus lens unit 12
The variable focus lens unit 12 is configured using a lens that can change the focal length of incident light with the lens position fixed. As such a lens, for example, a lens that changes the focal length of incident light by applying an electrical signal can be used. More specifically, a liquid lens that changes an interface shape according to a signal value or the like by applying an electrical signal or the like can be used. By using such a liquid lens, the focal length of the light incident on the variable focus lens unit 12 can be changed, and the light distribution angle of the light emitted from the light source 11 can be changed.

As an example of the lens constituting the variable focus lens unit 12, for example, a circular thin film (including a thin plate, the same applies hereinafter) made of two transparent materials that can be elastically deformed, and a frame that supports the thin film in parallel. The liquid lens is composed of a body and a transparent liquid filled in the thin film, and the surface of the thin film is deformed into a concave shape or a convex shape by applying a voltage (hereinafter referred to as “first mode” The liquid lens can be used. When a lens having such a configuration is used, since the curvature of the thin film changes as the center position of the thin film moves along the lens axis, the focal length of the lens can be changed. For example, silicone oil can be used as the transparent liquid filled in the thin film.

Further, as another example of the lens that forms the variable focus lens unit 12, the liquid lens 20 having the structure shown in FIG. 2 in which two kinds of liquid are accommodated (hereinafter referred to as “liquid lens of the second aspect” for convenience). May be adopted. A liquid lens 20 shown in FIG. 2 includes an electrically conductive liquid (conductive liquid layer) 22 and an insulating liquid (insulating liquid layer) in a substantially cylindrical container 21 formed of a transparent material such as acrylic resin. ) 23. These liquids have different refractive indexes and do not mix with each other. Note that an aqueous solution containing an electrolyte or the like can be used as the conductive liquid, for example. For example, silicone oil can be used as the insulating liquid. When a central line that is perpendicular to the bottom surface 21a (circular surface) of the container 21 and passes through the center of the bottom surface 21a is the central axis x of the lens, the conductive liquid layer 22 and the central axis x An insulating liquid layer 23 is laminated. An insulating member 24 having a predetermined inclination is provided on the side of the container 21 where the insulating liquid layer 23 is disposed. The distance between the insulating member 24 and the inner peripheral wall surface increases from the conductive liquid layer 22 side toward the insulating liquid layer 23 side, and a concave portion having a tapered cross section is formed in the container 21 by the insulating member 24. 25 is formed.

Electrodes

26 and 27 are provided on both sides of the container 21 in the thickness direction via the insulating member 24. When no voltage is applied between the

electrodes

26 and 27, the interface between the conductive liquid layer 22 and the insulating liquid layer 23 exhibits a curved surface shape having a certain curvature. When a voltage is applied between the

electrodes

26 and 27, the interface shape between the conductive liquid layer 22 and the insulating liquid layer 23 changes according to the applied voltage value due to a so-called electrowetting phenomenon. At this time, the focal position of the light incident on the liquid lens is changed by irradiating light from the light source 11 by moving the apex position of the interface (the position of the curved surface that protrudes most in the axial direction) along the central axis x. Can be moved back and forth along the optical axis. For example, in the illustrated example, the vertex position can be moved from a to a ′.

(3) Optical lens unit 13
Next, the optical lens unit 13 will be described. The optical lens unit 13 can be configured using a lens or a lens group having a predetermined refractive power. The lens group is a lens group in which a plurality of lenses are arranged along the optical axis and have a predetermined refractive power when viewed as a whole lens group.

Here, the predetermined refractive power means that the reciprocal of the focal length of the lens shows a predetermined value, and that the refractive power of the optical lens unit 13 does not change unlike the variable focus lens unit 12. . The refractive power of the optical lens unit 13 may be either positive or negative, and may be selected according to the light distribution angle required for the illumination device 10. For example, when the optical lens unit 13 has positive refractive power, that is, when it is configured as a convex lens, the light distribution angle (irradiation range) of light emitted from the illumination device 10 can be converged by the variable focus lens unit 12. It is possible to converge to a narrower range than a simple range. On the other hand, when the optical lens unit 13 has negative refractive power, the irradiation range of the light irradiated from the illumination device 10 can be diffused to a wider range than the range that can be diffused by the variable focus lens unit 12. it can. In other words, when it is necessary to converge light in a narrower range than the light distribution angle that can be changed by the variable focus lens unit 12, the optical lens unit 13 is configured using a lens or a lens group having positive refractive power. It is preferable to do. On the other hand, when it is necessary to scatter light over a wider range than the light distribution angle that can be changed by the variable focus lens unit 12, the optical lens unit 13 is configured using a lens or a lens group having a negative refractive power. It is preferable to do. The focal length of the lens or lens group constituting the optical lens unit 13 is appropriately determined according to the light distribution angle required for the illumination device 10 and the focal length changeable range of the variable focal lens unit 12. You can choose the one with the right value.

(4) Arrangement of Optical System Element 10a In the illumination device 10 of the present embodiment, as described above, the variable focus lens unit 12 and the optical lens unit 13 are arranged in series along the optical axis of the irradiation light of the light source 11, respectively. Each position is fixed. The separation distance between the variable focus lens unit 12 and the optical lens unit 13 with respect to the light source 11 is appropriately positioned according to the light distribution angle required for the illumination device 10.

1-2. Control system element 10b
Next, the control system element 10b of the illuminating device 10 of this Embodiment is demonstrated in order of the focus position change signal input part 14 and the control part 15. FIG. However, in the present invention, these control system elements 10b are arbitrary components, and the lighting device 10 according to the present invention is not necessarily provided with these control system elements 10b.

(1) Focus position change signal input unit 14
The focal position change signal input unit 14 inputs an instruction signal (hereinafter referred to as “focal position change signal”) for instructing a change in the focal position (focal length) of the variable focus lens unit 12 from the outside. It is an input device. The focal position change signal input unit 14 is not particularly limited as long as it can input the focal position change signal in some form. For example, the focal position change signal input unit 14 can be configured as a controller of the illumination device 10 used by the user. In this case, the controller includes an input unit for instructing the user to change the illumination range such as expansion or reduction of the illumination range of the illumination device 10, an input unit for instructing increase / decrease in the amount of illumination light, and the like. can do. These instruction signals relating to expansion or reduction of the illumination range, increase / decrease in the amount of illumination light, etc. input from the user side can be used as the focal position change signal. Further, for example, when the illumination device 10 is used for irradiating light to the imaging range of the imaging device, information regarding the imaging range can be used as the focal position change signal from the imaging device side. However, the information relating to the imaging range includes various information relating to imaging such as information relating to the position and size (view angle) of the imaging range, information relating to the brightness of the imaging range, and the like. Further, when the illumination device 10 receives input of information regarding the imaging range from the imaging device, the focal position change signal input unit 14 can be configured as a connection interface with the imaging device.

(2) Control unit 15
The control unit 15 is electrically connected to the focal position change signal input unit 14 and receives a focal position change signal from the focal position change signal input unit 14. The control unit 15 stores in advance association information in which various control signals to be output to the variable focus lens unit 12 are associated with various input focal position change signals. When a focus position change signal is input to the control unit 15 from the focus position change signal input unit 14, a predetermined control signal corresponding to the input focus position change signal is variable based on the association information. Output to the lens unit 12 to change the focal length of the variable focus lens unit 12. For example, when the focal length is changed in accordance with the voltage value applied to the variable focus lens unit 12, the control unit 15 determines that the voltage of the voltage value corresponding to the input focal position change signal is the variable focus lens unit. 12 to be applied.

According to the illumination device 10 of the present embodiment described above, the light emitted from the light source 11 can be incident on the optical lens unit 13 via the variable focus lens unit 12. Thereby, the light emitted from the variable focus lens unit 12 is refracted by the optical lens unit 13 at a predetermined refractive index. For this reason, the range in which the focal length of the variable focus lens unit 12 can be changed can be optically expanded by the optical lens unit 13. As described above, according to the present invention, the focal length can be changed in a wider range than the focal length changeable range of the variable focus lens unit 12 without changing the separation distance of the variable focus lens unit 12 from the light source 11. . Therefore, according to the present invention, the range in which the light distribution angle (irradiation range) can be changed can be optically expanded as compared with the conventional one without complicating and increasing the size of the apparatus. Can be diffused to a wider range or converged to a narrower range. Moreover, even when the requirements regarding the light distribution angles for the individual illumination devices 10 are different, the liquid lens or the like constituting the variable focus lens unit 12 can be used as a common component. That is, it is not necessary to create a liquid lens having a different focal length and aperture for each small-lot product (illumination device 10), and the illumination device (100) that illuminates a wide range using one type of liquid lens can be used in a narrow range. The present invention can be applied to any lighting device (100) (spotlight) for converging light, and a liquid lens can be used as a common component in manufacturing any lighting device (100).

Furthermore, in order to prevent the loss of light in the illumination device 10, it is preferable that the total luminous flux irradiated from the light source 11 is incident on the optical system. The light emitted from the light source 11 diffuses in a predetermined range, and the light diffusion range increases as the distance from the light source 11 increases. For this reason, in order to prevent the loss of light, it is necessary to increase the lens diameter of the variable focus lens unit 12 in accordance with the distance from the light source 11. However, for example, when the variable focus lens unit 12 is configured using a liquid lens, increasing the lens aperture of the liquid lens increases the capacity of the liquid accommodated therein, which increases the weight, which is not preferable. In order to suppress the increase in weight, it is conceivable to reduce the thickness of the liquid lens. However, when the thickness is reduced, the curvature of the liquid lens is increased, and as a result, the focal length is increased, so that the separation distance from the light source 11 is further increased. Therefore, the aperture of the liquid lens is limited to a predetermined size, and the separation distance between the light source 11 and the liquid lens is also limited to a predetermined range. Further, in the liquid lens, there is a certain limitation on the range in which the focal length can be changed depending on the refractive index of the liquid contained therein, the lens aperture, the voltage value that can be applied, and the like. Therefore, when the focal length of the light emitted from the light source 11 is changed only by the variable focus lens unit 12, the range in which the light distribution angle of the illumination device 10 can be changed becomes small. In particular, when a surface light source is employed as the light source 11, it is necessary to bring the variable focus lens unit 12 closer to the light source 11 in order to prevent light loss, and it is difficult to change the light distribution angle. Become. In contrast, the present invention employs a configuration in which the light emitted from the light source 11 is emitted to the outside via the variable focus lens unit 12 and the optical lens unit 13, and thus the variable focus lens with respect to the light source 11. Even when the unit 12 is brought close to the optical lens unit 13, the optical lens unit 13 can be adjusted to have a desired focal length. For this reason, in this invention, the variable focus lens part 12 can be comprised using a liquid lens etc. with a small lens aperture, and the light distribution angle requested | required of the said illuminating device 10 is the state which maintained the illumination efficiency high. Can be realized.

2. Imaging illumination device 30
Next, an embodiment of the imaging illumination device 30 according to the present invention will be described. The imaging illumination device 30 according to the present embodiment is an imaging illumination device 30 that projects light into the imaging region by the illumination device 10 according to the embodiment of the present invention described above, and changes the illumination range within the imaging region. It is possible to make it possible.

The configuration of the imaging illumination device 30 may be the same as that of the illumination device 10 described above. For example, a signal for instructing enlargement or reduction of the illumination range in the imaging region, increase / decrease in the amount of illumination light, or the like is input as the focus position change signal via the focus position change signal input unit 14, and according to these instruction signals Thus, it is more preferable to change the illumination range and the amount of illumination light by changing the focal length of the variable focus lens unit 12 by the control unit 15.

As described above, the illumination device 10 according to the present invention can form the variable focus lens unit 12 using a liquid lens having a small lens diameter, and can reduce the separation distance between the light source 11 and the variable focus lens unit 12. Can do. Therefore, by using the illumination device 10 as the imaging illumination device 30, the light projecting device can be reduced in weight and thickness. In addition, even when the angle of view of the imaging device is different, such as a wide-angle system or a telephoto system, using one type of liquid lens, it is possible to irradiate light at a light distribution angle corresponding to each imaging field angle. There is no need to create a liquid lens with a different focal length and aperture for each small-lot product (illumination device 10), and the liquid lens can be used as a common component in either a wide-angle system or a telephoto system.

3. Imaging system 100
Next, the imaging system of this embodiment will be described. As shown in FIG. 3, the imaging system 100 according to the present embodiment includes the above-described illumination device 10 according to the embodiment of the present invention and the imaging device 40, and the illumination device 10 and the imaging device 40 are electrically connected. It is connected. In the illumination device 10, the control unit 15 performs control so as to change the focal length of the light incident on the variable focus lens unit 12 based on the information regarding the imaging range input from the imaging device 40, and thereby the imaging device 40. According to the imaging range, the illumination device 10 illuminates a desired range, or adjusts the amount of illumination light on the irradiated surface. About the illuminating device 10, since the structure similar to the said illuminating device 10 and the imaging illuminating device 30 is employable, description is abbreviate | omitted here and the structure of the imaging device 40 is demonstrated hereafter.

(1) Imaging device 40
The imaging device 40 includes an imaging lens unit 41, a lens driving mechanism 42, an input unit 43, a connection unit 44, and the like, and a control unit 45 that controls the operation of the imaging device 40 including these. The imaging lens unit 41 includes a zoom lens, a focus lens, and the like. The lens driving mechanism 42 moves the zoom lens, the focus lens, and the like to predetermined positions under the control of the control unit 45, and causes the imaging lens unit to perform a zoom operation, a focus operation, and the like. The input unit 43 is configured, for example, as an operation unit that can be operated by a user or a connection interface that is connected to a remote personal computer (PC) by wire or wirelessly, and the zoom instruction, focus instruction, Information about the imaging range such as the brightness of the imaging range is input. The connection unit 44 is electrically connected to the focus position change signal input unit 14 as a connection unit on the illumination device 10 side by wire or wirelessly, and exchanges control signals and the like with the illumination device 10. Specifically, under the control of the control unit 45, information related to the imaging range of the imaging lens unit 41 is output to the illumination device 10 side. In the imaging system 100, the illumination device 10 changes the illumination range based on information regarding the imaging range input from the imaging device 40 side.

Here, the imaging device 40 may be a monitoring imaging device installed on a ceiling surface or a wall surface. Some surveillance imaging apparatuses are configured to be able to perform a zoom operation, a focus operation, and the like by a remote operation via a PC or the like. In the present invention, based on the information regarding the imaging range of the imaging device 40, the illumination device 10 also changes the focal length by the variable focus lens unit 12, so that the imaging range of the imaging device 40 changes according to the imaging range. The range is irradiated with light or the amount of illumination light is adjusted. Therefore, according to the present invention, the illumination range or the amount of illumination light can be changed according to the imaging range of the imaging device 40 without complicating and increasing the size of the configuration of the illumination device 10.

The illuminating device 10 and the imaging illuminating device 30 according to the present embodiment described above have been described as changing the focal length of light incident on the variable focus lens unit 12 mainly by electrical control, but according to the present invention. The illuminating device 10 and the imaging illuminating device 30 are not limited to the illuminating device 10 of the above embodiment, and can be appropriately changed without departing from the gist of the present invention.

For example, the control system element 10b (focal position change signal input unit 14, control unit 15) shown in FIG. 1 is not an essential configuration in the illumination device 10 and the imaging illumination device 30 of the present invention as described above. In the above-described embodiment, the variable focus lens unit 12 has been described as performing the focal length change control according to the focal position change signal input from the focal position change signal input unit 14. Alternatively, the focal length of the variable focus lens unit 12 may be set in advance to be a predetermined position according to the installation position of the imaging illumination device 30. Even in this case, the amount of illumination light, the illumination range, etc. of the illumination device 10 or the imaging illumination device 30 can be appropriately changed according to the installation position of the illumination device 10 or the imaging illumination device 30. . In this case, not only a liquid lens whose curvature is changed by an electrical signal, but also a liquid lens configured to change the curvature by a mechanical mechanism can be suitably used. Specifically, the liquid lens that changes the curvature by a mechanical mechanism has the same configuration as the liquid lens of the first aspect, and is formed on the lens frame by rotating the lens frame. The liquid contained between the thin films is exchanged with the liquid container, and the volume of the liquid between the thin films is changed, thereby deforming the surface shape of the thin film into a concave shape or a convex shape. Can be used. In the present invention, a liquid lens having a configuration in which the focal length is changed by such a mechanical mechanism can also be suitably employed, and the focal length of the variable focus lens unit 12 may be changed manually.

In addition, in a liquid lens having the same configuration as the liquid lens 20 of the second aspect, the configuration of the

electrodes

26 and 27 and the control of the voltage value applied between the

electrodes

26 and 27 are changed to change the conductivity. In some cases, the vertex position of the interface between the conductive liquid layer 22 and the insulating liquid layer 23 can be moved to a position different from the central axis. When such a liquid lens that can move the vertex position of the interface to a position different from the central axis is employed, the optical axis direction of the light emitted from the light source 11 can be changed. In this case, since the focal length and the optical axis direction can be changed in the variable focus lens unit 12, the illumination range of the illumination device 10 can be changed and the illumination direction can be changed.

Next, the present invention will be described more specifically with respect to the lighting device 10 by way of examples. However, the present invention is not limited to the following examples.

In FIG. 4, the structural example of the illuminating device 10 of Example 1 is shown. In the illumination device 10 of Example 1, a point light source is employed as the light source 11, and the liquid lens according to the second aspect described above is used as the variable focus lens unit 12. In addition, a lens (convex lens) having a positive refractive power is employed as the optical lens unit 13. As described above, the convex lens may be replaced with a convex lens group in which a plurality of optical lenses are combined.
However, FIG. 4A shows an example in which the variable focus lens unit 12 functions as a convex lens, and FIG. 4B shows an example in which the variable focus lens unit 12 functions as a concave lens. (The same applies to FIGS. 5 to 10 below).

FIG. 5 shows a configuration example of the illumination device 10 according to the second embodiment. In the illuminating device 10 of Example 2, the structure similar to the illuminating device 10 of Example 1 was employ | adopted as the optical lens part 13 except having employ | adopted the lens (concave lens or concave lens group) which has negative refractive power.

FIG. 6 shows a configuration example of the lighting device 10 of the third embodiment. In the illuminating device 10 of Example 3, the structure similar to the illuminating device 10 of Example 1 was employ | adopted as the light source 11 except having employ | adopted the surface light source instead of the point light source.

FIG. 7 shows a configuration example of the illumination device 10 according to the fourth embodiment. In the illuminating device 10 of Example 4, the same configuration as that of the illuminating device 10 of Example 3 was adopted except that a lens having a negative refractive power (concave lens or concave lens group) was adopted as the optical lens unit 13.

FIGS. 8A and 8B show an embodiment of the imaging illumination device 40 and the imaging system 100 according to the present invention. An imaging system 100 illustrated in FIGS. 8A and 8B includes the illumination device 10 according to the first embodiment and an imaging device 40 having a specific configuration described below, and from the imaging device 40 side to the illumination device 10 side. The illumination range of the illumination device 10 and the amount of illumination light can be changed based on the information regarding the imaging range input to. The imaging device 40 includes, as an imaging lens unit 41, a lens barrel 41a, a zoom lens 41b (zoom lens group) and a focus lens 41c (focus lens group) that are movably provided in the lens barrel 41a, and these A zoom lens sensor 41d and a focus lens sensor 41e for detecting the position of the lens are provided. The zoom lens 41b and the focus lens 41c are moved to predetermined positions by the lens driving mechanism 42 (not shown in FIG. 8) under the control of the control unit 45 (not shown in FIG. 8). Information relating to the imaging range such as the imaging angle of view and imaging position of the imaging device 40 is output to the lighting device 10 side via the connection unit 44 under the control of the control unit 45. FIGS. 8A and 8B are examples in which the illumination light amount irradiated to the imaging range W by the illumination device 10 is adjusted based on information about the brightness of the imaging range W as information about the imaging range W of the imaging device 40. Show.

Comparative example

[Comparative Example 1]
In FIG. 9, the structural example of the illuminating device 10 of the comparative example 1 is shown. The illumination device 10 of Comparative Example 1 employs the same configuration as that of the illumination device 10 of Example 1 or Example 2 except that the optical lens unit 13 is not provided.

[Comparative Example 2]
In FIG. 10, the structural example of the illuminating device 10 of the comparative example 2 is shown. In the illumination Suchi of the comparative example 2, except having not provided the optical lens part 13, the structure similar to the illuminating device 10 of Example 3 or Example 4 was employ | adopted.

[Evaluation]
(1) When Point Light Source is Employed First, the lighting device 10 of Example 1 and Example 2 and the lighting device of Comparative Example 1 that employ a point light source as the light source 11 are evaluated. As shown in Comparative Example 1, when the illumination device is configured only from the point light source as the light source 11 and the liquid lens 20 as the variable focus lens unit 12, when the liquid lens 20 functions as a convex lens, the liquid lens When the focal position of 20 coincides with the position of the point light source, the light emitted from the point light source is converted into a parallel light flux. Further, when the liquid lens 20 is made to function as a concave lens, the light incident on the liquid lens 20 is larger than the light distribution angle of the light emitted from the point light source, and the illumination light can be irradiated over a wider range. it can. As described above, since the focal position variable range of the liquid lens 20 has a certain limitation, the light distribution angle of the illumination device of Comparative Example 1 remains within the range in which the focal position can be changed by the liquid lens 20. . On the other hand, as shown in FIGS. 4A and 4B, in the illumination device 10 according to the first embodiment, the light emitted from the point light source serving as the light source 11 has a positive refractive power via the variable focus lens unit 12. It is made to enter into the optical lens part 13 which has. Thereby, as shown in FIGS. 4A and 4B, the light emitted from the variable focus lens unit 12 can converge the light in a narrower range than the illumination device of Comparative Example 1. . 5A and 5B, in the illuminating device 10 according to the second embodiment, the light emitted from the point light source serving as the light source 11 has a negative refractive power via the variable focus lens unit 12. It is made to enter into the optical lens part 13 which has. As a result, as shown in FIGS. 5A and 5B, the light emitted from the variable focus lens unit 12 can diffuse light over a wider range than the illumination device of Comparative Example 1. .

(2) When Surface Light Source is Employed Next, the lighting devices 10 of Example 3 and Example 4 and the lighting device 10 of Comparative Example 2 that employ a surface light source are evaluated. As shown in Comparative Example 2, in the case where the illumination device is configured only from the surface light source as the light source 11 and the liquid lens 20 as the variable focus lens unit 12, the surface light source was irradiated to prevent light loss. Since it is necessary to arrange the liquid lens 20 so that all the light enters the liquid lens 20, the surface light source as the light source 11 and the liquid lens 20 are arranged close to each other (see FIG. 10). Here, when the liquid lens 20 is caused to function as a convex lens, the light emitted from the surface light source converges and the light distribution angle is narrowed. However, since the liquid lens 20 must be disposed close to the surface light source, the diffusion range of the light emitted from the surface light source is slightly narrowed even when the focal position of the liquid lens 20 is changed. Not too much. On the other hand, when the liquid lens 20 is caused to function as a concave lens, the light incident on the liquid lens 20 is diffused and the light distribution angle is expanded. However, also in this case, in order to prevent the loss of light, the distance between the surface light source and the liquid lens 20 must be reduced, and the expandable range is small compared to the case where a point light source is employed. Become.

On the other hand, as shown in FIGS. 6A and 6B, in the illumination device 10 according to the third embodiment, the light emitted from the surface light source is an optical lens unit having a positive refractive power via the variable focus lens unit 12. 13 is incident. As a result, as shown in FIGS. 6A and 6B, the light emitted from the variable focus lens unit 12 can converge the light in a narrower range than the illumination device of Comparative Example 2. become. Further, as shown in FIGS. 7A and 7B, in the illumination device 10 according to the fourth embodiment, the light emitted from the surface light source is an optical lens unit having a negative refractive power via the variable focus lens unit 12. 13 is incident. As a result, as shown in FIGS. 7A and 7B, the light emitted from the variable focus lens unit 12 can diffuse light over a wider range than the illumination device of Comparative Example 2. become.

(3) Adjustment of illumination light quantity Next, the example which adjusted the illumination light quantity in the imaging illumination device 30 (illumination device 10) and the imaging system 100 shown in Example 5 is demonstrated.
In the fifth embodiment described above, the imaging illumination device 30 calculates the focal length in the variable focus lens unit 12 based on information related to the imaging range input from the imaging device 40, specifically, information related to the brightness of the imaging range. An example of operation in which the amount of illumination light is changed by being moved is shown. As shown in FIGS. 8A and 8B, the imaging range W of the imaging device 40 has the same position and size (angle of view). In the example shown in FIG. 8A, the illumination range is adjusted so that illumination light is irradiated on the subject surface 101 in substantially the same range as the imaging range W. On the other hand, in the example illustrated in FIG. 8B, the illumination range is adjusted so that the illumination light is irradiated to a range larger than the imaging range W of the imaging device 40. As described above, even when the imaging ranges are the same, the illumination light quantity in the imaging range can be adjusted based on information such as the brightness of the imaging range by changing the focal length of the focus variable lens unit 12. Although illustration is omitted, in such an imaging system 100, when the size of the imaging range of the imaging device 40 is changed using the illumination device described in the first to fourth embodiments, the imaging range is changed. Of course, the illumination range may be changed according to the size so that the illumination range of the imaging illumination device 30 substantially matches the size of the imaging range.

According to the present invention, the light emitted from the light source can be incident on the optical lens unit via the variable focus lens unit. Thereby, the light emitted from the variable focus lens unit is refracted at a predetermined refractive index by the optical lens unit. For this reason, the changeable range of the focal position in the variable focus lens unit can be optically expanded by the optical lens unit. As described above, according to the present invention, the focal position can be changed in a wider range than the focal position changeable range of the variable focus lens unit without changing the separation distance of the variable focus lens unit from the light source. Therefore, according to the present invention, the range in which the light distribution angle (irradiation range) can be changed can be optically expanded as compared with the conventional one without complicating and increasing the size of the apparatus. Can be diffused to a wider range or converged to a narrower range. In addition, even when the requirements regarding the light distribution angles for the individual illumination devices are different, the liquid lens or the like constituting the variable focus lens unit can be used as a common component. For this reason, for example, when used as an illumination device for imaging, it is possible to realize a light distribution angle corresponding to the angle of view of a captured image, such as a wide-angle system or a telephoto system, with a single liquid lens. As described above, the illumination device of the present invention can be applied to an illumination device in which the irradiation angle is variable, and can also be used when manufacturing a plurality of types of illumination devices having different irradiation angles.

DESCRIPTION OF SYMBOLS 10 ... Illuminating device 11 ... Light source 12 ... Variable focus lens part 13 ... Optical lens part 14 ... Focus position change signal input part 15 ... Control part 20 ... Liquid lens 30. ..Imaging illumination device 100 ..Imaging system

Claims

An illumination device that includes a light source and an optical lens unit having a predetermined refractive power, and emits light emitted from the light source through the optical lens unit,
A variable focus lens unit capable of changing a focal length in a state where a lens position is fixed is provided between the light source and the optical lens unit, and the light emitted from the light source passes through the variable focus lens unit. Incident on the optical lens unit,
A lighting device characterized by the above.
2. The illumination device according to claim 1, wherein the variable focus lens unit is a liquid lens that changes a focal length based on a focus position change signal input from the outside.
3. The illumination device according to claim 2, wherein the focal position change signal is information related to an imaging range input from the imaging device.
An imaging illumination device that irradiates light in an imaging region with the illumination device according to claim 1,
An imaging illumination device characterized in that an illumination range in an imaging region can be changed.
An illumination device that includes a light source and an optical lens unit having a predetermined refractive power, emits light emitted from the light source through the optical lens unit, and imaging that can change an imaging range within a predetermined imaging region An imaging system comprising a device,
The lighting device includes:
A variable focus lens unit capable of changing a focal length with a lens position fixed between the light source and the optical lens unit,
An input unit for inputting information on the imaging range from the imaging device;
A control unit that controls to change a focal length of light incident on the variable focus lens unit based on information on an imaging range input from the input unit;
An imaging system comprising: