WO2014006925A1

WO2014006925A1 - Lighting device

Info

Publication number: WO2014006925A1
Application number: PCT/JP2013/054005
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: 2013-02-19
Publication date: 2014-01-09
Also published as: JP2014013738A

Abstract

The present invention addresses the problem of providing a lighting device that is capable of using a liquid lens with a small diameter, and that has high lighting efficiency. In order to solve this problem, the present invention provides a lighting device that is characterized by being provided with a light source (11), a converging lens (12) having a positive refractive power, and a variable focus lens (13) wherein the focus position can be changed with the lens position in a fixed state, in that order. The lighting device is further characterized in that the converging lens (12) causes the beam diameter of emitted light that is emitted from the light source (11) to converge to the diameter of the variable focus lens (13) or less, and causes the beam to enter the variable focus lens (13).

Description

Lighting device

The present invention relates to a lighting device, and more particularly to a lighting device capable of changing an illumination range or a light projection range.

2. Description of the Related Art Conventionally, there is known an illumination device that includes a light source and an optical lens and emits light emitted from the light source through the optical lens. 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 illumination device described in Patent Document 1, illumination light is irradiated to a predetermined range by changing the light distribution angle of light emitted from the light source to a narrow angle or a wide angle according to a required illumination effect. be able to.

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, the light source and the liquid lens may not be brought close to each other due to the influence of heat generated in the light source or mechanical limitations. In order to realize an illumination device with high illumination efficiency, it is necessary to make the total luminous flux emitted from the light source enter the lens. For this reason, it is necessary to use a lens having a large lens diameter as the distance between the light source and the liquid lens increases. However, when a liquid lens is used as the lens, it is expensive to manufacture a liquid lens having a large lens diameter. Further, when the lens diameter of the liquid lens is increased, it becomes difficult to precisely control the liquid surface shape, and the lens performance may be deteriorated. Therefore, it is not preferable to increase the lens diameter.

Therefore, an object of the present invention is to provide an illumination device that can employ a liquid lens having a small lens diameter and has high illumination efficiency.

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, a converging lens unit having a positive refractive power, and a variable focus lens unit capable of changing a focal position in a state where the lens position is fixed, in the order, and the converging lens The light beam diameter of the emitted light emitted from the light source is converged to be equal to or smaller than the lens diameter of the variable focus lens unit, and is incident on the variable focus lens unit.

In the illumination device according to the present invention, it is preferable that a lens diameter of the variable focus lens unit is formed smaller than a lens diameter of the convergent lens unit.

In the illumination apparatus according to the present invention, it is preferable that an optical lens unit having a predetermined refractive power is provided on the downstream side of the optical path of the variable focus lens unit.

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 focus position 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.

According to the present invention, the light source, the converging lens unit, and the variable focal lens unit are provided in this order, and the converging lens unit converges the luminous flux diameter of the emitted light to be equal to or smaller than the lens diameter of the focal variable lens unit, Since the light is incident on the variable focus lens unit, the entire luminous flux of the emitted light emitted from the light source can be incident on the variable focus lens unit even if the lens diameter of the variable focus lens unit is small. Therefore, even when it is necessary to increase the separation distance between the light source and the variable focus lens unit due to the prevention of the influence of heat of the light source, mechanical restrictions, etc., the variable focus lens unit using a liquid lens with a small lens diameter It is possible to provide an illumination device with high illumination efficiency. In addition, even when the separation distance between the light source and the variable focus lens unit in each lighting device is different, the liquid lens or the like constituting the variable focus lens unit can be used as a common component, thereby reducing costs. Can be planned.

It is a block diagram which shows an example of a functional structure of the illuminating device which concerns on this invention. It is a schematic diagram which shows an example of a liquid lens. 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 which concerns on this invention. It is a schematic diagram which shows the specific structural example (Example 6) of the illuminating device which concerns on this invention.

Hereinafter, a preferred embodiment of a lighting 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, a converging lens unit 12 having a positive refractive power, and a variable focus lens unit that can change a focal position while fixing the lens position. 13 in this order, and the convergent lens unit 12 converges the luminous flux diameter of the emitted light to be equal to or smaller than the lens diameter of the variable focus lens unit 13 and enters the variable focus lens unit 13. To do.

Further, as shown in FIG. 1, the illumination device 10 of the present embodiment includes an optical lens unit 14 having a predetermined refractive power on the downstream side of the optical path of the variable focus lens unit 13, and each of these optical system elements 10a. The converging lens unit 12, the variable focus lens unit 13, and the optical lens unit 14 are arranged with a predetermined separation distance in order along the optical path of the light emitted from the light source 11. In addition to these optical system elements 10a, the illumination device 10 of the present embodiment includes a focus position change signal input unit 15 and a control unit 16 as a control system element 10b for electrically controlling the variable focus lens unit 13. And. 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) Converging lens unit 12
As described above, the converging lens unit 12 has a positive refractive power, and is configured using, for example, a lens having a positive refractive power such as a convex lens or a convex lens group or a lens group having a positive refractive power as a whole. . When the converging lens unit 12 is configured by a lens group composed of a plurality of lenses, it is only necessary to show positive refractive power as the entire lens group, and the specific configuration is not limited. That is, the converging lens unit 12 condenses or converts the emitted light diffused and irradiated from the light source 11 into parallel light so that the diameter of the light beam is smaller than the lens diameter of the variable focus lens unit 13, and the variable focus lens unit 13. Any lens configuration may be used as long as it can enter the lens.

(3) Variable focus lens unit 13
The variable focus lens unit 13 is configured using a lens that can change the focal position of incident light with the lens position fixed. As such a lens, for example, a lens that changes the focal position 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 position of the light incident on the variable focus lens unit 13 can be changed, and the light distribution angle of the light emitted from the light source 11 can be changed.
However, in the present embodiment, changing the focal position refers to changing the focal length of the lens, and more specifically, moving the focal position back and forth along the optical axis.

As an example of the lens constituting the variable focus lens unit 13, for example, a circular thin film (including a thin plate; the same applies hereinafter) made of two elastically deformable transparent materials and a frame for supporting 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 the lens having such a configuration is used, the focal position of the lens can be changed because the curvature of the thin film changes as the center position of the thin film moves along the lens axis. For example, silicone oil can be used as the transparent liquid filled in the thin film.

Further, as another example of the lens constituting the variable focus lens unit 13, the liquid lens 20 having the structure shown in FIG. 2 in which two kinds of liquids 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 light source 11 emits the focal position of the light incident on the liquid lens 20 by moving the apex position of the interface (the position of the curved surface that protrudes in the most axial direction) along the central axis x. It can be moved back and forth along the optical axis of light. For example, in the illustrated example, the vertex position can be moved from a to a ′.

Here, the variable focus lens unit 13 may employ any of the above-described liquid lenses, but the lens diameter of the focus lens unit 13 is formed smaller than the lens diameter of the converging lens unit 12. Is preferred. However, the lens diameter of the variable focus lens unit 13 refers to the lens diameter when the variable focus lens unit 13 is formed using one liquid lens as described above. Further, if the variable focus lens unit 13 is formed using a plurality of liquid lenses or the like, this indicates the maximum lens diameter (maximum lens diameter) of each lens. Similarly, the lens diameter of the converging lens unit 12 refers to the lens diameter when the converging lens unit 12 is formed using one optical lens, and the converging lens unit 12 includes a plurality of optical lenses. When formed using a lens or the like, the maximum lens diameter (maximum lens diameter) among the lens diameters of each optical lens or the like is indicated.

(4) Optical lens unit 14
Next, the optical lens unit 14 will be described. The optical lens unit 14 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 14 does not change unlike the variable focus lens unit 13. . The refractive power of the optical lens unit 14 may be either positive or negative, and may be selected according to the light distribution angle required for the illumination device 10 or the like. For example, when the optical lens unit 14 has a 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 13. It is possible to converge to a narrower range than a simple range. On the other hand, when the optical lens unit 14 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 13. it can. In other words, when it is necessary to converge light in a range narrower than the light distribution angle that can be changed by the variable focus lens unit 13, the optical lens unit 14 is configured using a lens or a lens group having a 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 13, the optical lens unit 14 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 14 is appropriately determined according to the light distribution angle required for the illumination device 10 and the focus position changeable range of the variable focus lens unit 13. You can choose the one with the right value.

(5) Arrangement of Optical System Element 10a In the illumination device 10 of the present embodiment, as described above, the converging lens unit 12, the variable focus lens unit 13, and the optical lens unit 14 are each on the optical axis of the irradiation light of the light source 11. Are arranged in series along each other, and each position is fixed. The separation distances of the convergent lens unit 12, the variable focus lens unit 13, and the optical lens unit 14 with respect to the light source 11 are appropriately set appropriately according to the light distribution angle required for the illumination device 10, respectively. Positioned.

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 15 and the control part 16. 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 15
The focal position change signal input unit 15 inputs an instruction signal (hereinafter referred to as “focal position change signal”) for instructing the change of the focal position (focal length) of the variable focus lens unit 13 from the outside. It is an input device. The focal position change signal input unit 15 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 15 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 15 can be configured as a connection interface with the imaging device.

(2) Control unit 16
The control unit 16 is electrically connected to the focal position change signal input unit 15, and receives the focal position change signal from the focal position change signal input unit 15. The control unit 16 stores in advance association information in which various control signals to be output to the variable focus lens unit 13 are associated with various input focal position change signals. When a focus position change signal is input from the focus position change signal input unit 15 to the control unit 16, a predetermined control signal corresponding to the input focus position change signal is variable based on the association information. Output to the lens unit 13 to change the focal length of the variable focus lens unit 13. For example, when the focal length is changed in accordance with the voltage value applied to the variable focus lens unit 13, the control unit 16 determines that the voltage of the voltage value corresponding to the input focal position change signal is the variable focus lens unit. 13 to be applied.

According to the illuminating device 10 of this Embodiment demonstrated above, the light source 11, the converging lens part 12, and the focus variable lens part 13 are provided in the said order, and the light beam diameter of emitted light is provided by the converging lens part 12. Since the light beam is converged to be equal to or smaller than the lens diameter of the variable focus lens unit 13 and is incident on the variable focus lens unit 13, the entire luminous flux of the emitted light emitted from the light source 11 is focused even when the variable diameter lens unit 13 has a small lens diameter. The light can enter the variable lens unit 13. Therefore, even when it is necessary to provide a certain distance or more between the light source 11 and the variable focus lens unit 14 due to prevention of the influence of heat of the light source 11 and mechanical restrictions, a liquid lens (with a small lens diameter) ( 20) can be used to configure the variable focus lens unit 13, and it is possible to provide the illumination device 10 with high illumination efficiency. Further, even if the distance between the light source 11 and the variable focus lens unit 13 is different in each lighting device 10, the diameter of the light beam incident on the variable focus lens unit 13 is adjusted by the converging lens unit 12. Therefore, the liquid lens 20 or the like constituting the variable focus lens unit 13 can be used as a common component, so that the cost can be reduced.

Further, the illumination device 10 of the present embodiment has an optical lens unit 14 having a predetermined refractive power on the downstream side of the optical path of the variable focus lens unit 12. The optical lens unit 14 can change the focal position in an optically wider range than the focal position that can be changed in the variable focus lens unit 13. Therefore, according to the illuminating device 10 of this Embodiment, compared with the case where a focus position is changed only by the focus variable lens part 13, the range which can change a light distribution angle (irradiation range) is optically expanded. Therefore, the illumination light can be diffused to a wider range or converged to a narrower range.

Further, the illumination device 10 of the present embodiment can refract the emitted light from the light source 11 with a predetermined refractive index by the converging lens unit 12. In addition, the optical lens unit 14 can further refract the light emitted from the variable focus lens unit 13 with a predetermined refractive index. For this reason, the light distribution angle of each illuminating device 10 can be adjusted to a desired angle by appropriately adjusting the refractive powers of the converging lens unit 12 and the optical lens unit 14, respectively. Further, even when the requirements regarding the light distribution angles of the individual lighting devices 10 are different, the liquid lens or the like constituting the variable focus lens unit 13 can be used as a common component. That is, it is not necessary to create liquid lenses having different focal lengths and lens diameters for each small-lot product (illumination device 10), and the illumination device (100) that illuminates a wide range using one type of liquid lens, a narrow range The liquid lens (20) having a small lens diameter can be used as a common component when manufacturing any of the lighting devices (100). Can be used.

2. Imaging device illumination device 30
Next, an embodiment in the case where the illumination device 10 is used as the imaging device illumination device 30 will be described. The imaging device illumination device 30 according to the present embodiment is an imaging device illumination device 30 that irradiates illumination light into an imaging region by the above-described illumination device 10 according to the embodiment of the present invention. The illumination range can be changed.

The configuration of the imaging device illumination device 30 may be the same as that of the illumination device 10 described above. For example, a signal for instructing increase / decrease in the amount of illumination light in the imaging region, enlargement / reduction of the illumination range, or the like is input as a focus position change signal via the focus position change signal input unit 15, and the response to these instruction signals Thus, it is more preferable to change the illumination range by controlling the focal position of the variable focus lens unit 13 by the control unit 16.

As described above, the illumination device 10 of the present invention can form the variable focus lens unit 13 using a liquid lens having a small lens diameter. In addition, the convergent lens unit 12 can cause the total luminous flux of the light emitted from the light source 11 to enter the variable focus lens unit 13. Therefore, by using the lighting device 10 as the imaging device lighting device 30, the lighting device 10 (30) 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. It is not necessary to create a liquid lens having a different focal length and lens diameter 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.

The illumination device 10 and the imaging device illumination device 30 of the present embodiment described above have been described as changing the focal position of light incident on the variable focus lens unit 13 mainly by electrical control. The illumination device 10 and the imaging device illumination device 30 are not limited to the illumination device 10 and the imaging device illumination device 30 of the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention. .

For example, the control system element 10b (the focal position change signal input unit 15 and the control unit 16) shown in FIG. 1 is not an essential configuration in the illumination device 10 and the imaging device illumination device 30 of the present invention as described above. In the embodiment described above, the focus variable lens unit 13 has been described as performing focus position change control in accordance with the focus position change signal input from the focus position change signal input unit 15. Or according to the installation position of the said imaging device illumination device 30, you may set so that the focus position of the focus variable lens part 13 may become a predetermined position previously. Even in this case, the light distribution angle of the illumination device 10 or the imaging device illumination device 30 is changed according to the installation position or the like of the illumination device 10 or the imaging device illumination device 30. The illumination range and the like can be adjusted as appropriate. 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 position is changed by such a mechanical mechanism can be preferably employed, and the focal position of the variable focus lens unit 13 may be manually changed.

In the above-described embodiment, the focus variable lens unit 13 has been described mainly using the liquid lens 20 that moves the focal position back and forth along the optical axis of the emitted light emitted from the light source 11 as an example. The lighting device 10 according to the present invention is not limited to this. For example, in a liquid lens having the same configuration as that of 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 can be changed. 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, the light distribution direction of the illumination device 10 can be changed. Also in this case, the light distribution direction can be changed within a wider area than the area where the light distribution direction can be changed by the variable focus lens unit 13.

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. 3, the structural example of the illuminating device 30 (10) of Example 1 is shown. In the illumination device 30 of the first embodiment, a point light source is employed as the light source 11 and a lens (convex lens) having a positive refractive power is employed as the converging lens unit 12. And the liquid lens 20 of the 2nd aspect mentioned above was used as the focus variable lens part 13, and these were arrange | positioned in order along the optical axis of the emitted light radiate | emitted from the light source 11. FIG.
However, FIG. 3A shows an example in which the variable focus lens unit 13 functions as a convex lens, and FIG. 3B shows an example in which the variable focus lens unit 13 functions as a concave lens. (The same applies to FIGS. 4 to 8). In FIG. 3, the dotted line indicates the optical path, and the alternate long and short dash line indicates the optical axis (hereinafter the same applies to FIGS. 4 to 8).

As shown in FIG. 3, the emitted light emitted from the light source 11 diffuses at a predetermined diffusion angle. If the converging lens unit 12 is not provided between the light source 11 and the variable focus lens unit 13, the luminous flux diameter of the emitted light increases as the distance from the light source 11 increases, and the variable focus lens unit 13 In order to make the total luminous flux of the emitted light incident, it is necessary to make the lens diameter much larger than the example shown in FIG. However, in the illuminating device 30 of the first embodiment, the converging lens unit 12 is provided between the light source 11 and the variable focus lens unit 13, and the light beam diameter of the emitted light is made incident on the liquid lens 20 by the converging lens unit 12. Since the surface is converged so as to be smaller than the lens diameter of the liquid lens 20, the lens diameter is small even when the separation distance between the light source 11 and the variable focus lens unit 13 is more than a certain distance. Even when the liquid lens 20 is used, the variable focus lens unit 13 can be configured. Further, the light distribution angle can be adjusted as shown in FIGS. 3A and 3B by changing the curvature of the variable focus lens unit 13 and appropriately changing the focal position. These points are the same in the following Examples 2 to 6.

FIG. 4 shows a configuration example of the illumination device 40 (10) of the second embodiment. The illuminating device 40 of Example 2 is the same as the illuminating device 30 of Example 1 except that the optical lens unit 14 configured using a convex lens having positive refractive power is disposed on the downstream side of the optical path of the variable focus lens unit 13. Adopted the configuration. Of course, a lens group having positive refractive power as a whole may be used instead of the convex lens.

In the illuminating device 40 of Example 2, as shown in FIG. 4A, when the variable focus lens 13 is used as a convex lens, it has a positive refractive power downstream of the focal position of the variable focus lens 13 in the optical path. An optical lens unit 14 is provided. Since the optical lens unit 14 has a positive refractive power, it can converge the incident light and narrow the light distribution angle. Therefore, when the variable focus lens unit 13 is used as a convex lens or a concave lens, the light distribution angle of the illumination device 40 can be narrowed as compared with the illumination device 30 of the first embodiment. That is, by providing the optical lens unit 14 having a positive refractive power, the illumination range of the illumination device 40 can be changed in a narrower range.

Next, FIG. 5 shows a configuration example of the illumination device 50 (10) of the third embodiment. The illumination device 50 according to the third embodiment is the same as the illumination device 30 according to the first embodiment except that the optical lens unit 14 configured using a concave lens having negative refractive power is disposed on the downstream side of the optical path of the variable focus lens unit 13. Adopted the configuration. Of course, a lens group having negative refractive power as a whole may be used instead of the concave lens.

The illumination device 50 of Example 3 has the same configuration as that of the illumination device 40 of Example 2 except that the refractive power of the optical lens unit 14 is negative. Since the optical lens unit 14 has a negative refractive power, the light incident on the optical lens unit 14 diffuses. Therefore, as shown in FIGS. 5A and 5B, the illumination device is different from the illumination device 30 of Example 1 when the variable focus lens unit 13 is used as a convex lens or a concave lens. 10 light distribution angles can be expanded. That is, by providing the optical lens unit 14 having negative refractive power, the illumination range of the illumination device 50 can be changed in a wider range.

FIG. 6 shows a configuration example of the illumination device 60 (10) of the fourth embodiment. In the illuminating device 60 of Example 4, the structure similar to the illuminating device 30 of Example 1 was employ | adopted except having comprised the converging lens part 12 by the lens group which consists of a convex lens and a concave lens. Note that the convex lens may be replaced with one using two single-sided convex lenses so that the convex surfaces face each other.

In the illuminating device 60 of the fourth embodiment, the converging lens unit 12 is configured by a lens group including a convex lens and a concave lens, so that the light beam diameter of light incident on the variable focus lens unit 13 is compared with the illuminating device of the first embodiment. Can be slightly enlarged. Accordingly, as shown in FIGS. 6A and 6B, the light distribution angle different from that of the illumination device 30 of the first embodiment is used regardless of whether the variable focus lens unit 13 is used as a convex lens or a concave lens. Light can be irradiated.

Next, the lighting device 70 (10) of Example 5 will be described. The illuminating device 70 of Example 5 shown in FIG. 7 has the same configuration as that of the illuminating device 40 of Example 2, and includes an optical lens unit 14 having positive refractive power on the downstream side of the optical path of the variable focus lens unit 13. ing. In the illuminating device 70 of Example 5, after converging the emitted light emitted from the light source 11 by the converging lens unit 12 so that the focal point is located between the converging lens unit 12 and the variable focus lens unit 13, Diffused light that has been diffused again is incident on the variable focus lens unit 13. For this reason, illumination light can be irradiated at a different light distribution angle from the illumination device 10 of the second embodiment.

Next, the lighting device 80 (10) of Example 6 will be described. The illuminating device 80 of Example 6 shown in FIG. 8 has the same configuration as the illuminating device 50 of Example 3, and includes an optical lens unit 14 having negative refractive power on the downstream side of the optical path of the variable focus lens unit 13. ing. In the illuminating device 80 of Example 6, the focal point of the outgoing light emitted from the light source 11 by the converging lens unit 12 is positioned between the converging lens unit 12 and the variable focus lens unit 13 in the same manner as in Example 5. Then, the diffused light diffused again is made incident on the variable focus lens unit 13. For this reason, illumination light can be irradiated at a light distribution angle different from that of the illumination device 50 of the third embodiment.

As described above, in the illumination devices 10 (30 to 80) of the first to sixth embodiments, even if the liquid lens 20 constituting the variable focus lens unit 13 is used as a common component, the converging lens unit 12 and the optical lens unit. By appropriately adjusting the refractive power of 14, it becomes possible to irradiate light at various light distribution angles as shown in FIGS.

According to the present invention, the light source, the converging lens unit, and the variable focal lens unit are provided in this order, and the converging lens unit converges the luminous flux diameter of the emitted light to be equal to or smaller than the lens diameter of the focal variable lens unit, Since the light is incident on the variable focus lens unit, the entire luminous flux of the emitted light emitted from the light source can be incident on the variable focus lens unit even if the lens diameter of the variable focus lens unit is small. Therefore, even when it is necessary to increase the separation distance between the light source and the variable focus lens unit due to the prevention of the influence of heat of the light source, mechanical restrictions, etc., the variable focus lens unit using a liquid lens with a small lens diameter It is possible to provide an illumination device with high illumination efficiency. In addition, even when the separation distance between the light source and the variable focus lens unit in each lighting device is different, the liquid lens or the like constituting the variable focus lens unit can be used as a common component, thereby reducing costs. You can plan.

DESCRIPTION OF SYMBOLS 10 ... Illuminating device 10a ... Optical system element 10b ... Control system element 11 ... Light source 12 ... Converging lens part 13 ... Variable focus lens part 14 ... Optical lens part 15 ... Focus Position change signal input unit 16 ... control unit 20 ... liquid lens

Claims

A light source, a converging lens unit having a positive refractive power, and a variable focus lens unit capable of changing a focal position in a state where the lens position is fixed, in that order,
An illuminating apparatus characterized in that the convergent lens unit converges the light beam diameter of the emitted light emitted from the light source to be equal to or smaller than the lens diameter of the variable focus lens unit and enters the variable focus lens unit.
2. The illumination device according to claim 1, wherein a lens diameter of the variable focus lens unit is formed to be smaller than a lens diameter of the converging lens unit.
The illumination device according to claim 1 or 2, further comprising an optical lens unit having a predetermined refractive power on a downstream side of the optical path of the variable focus lens unit.
The illumination device according to any one of claims 1 to 3, wherein the focus variable lens unit is a liquid lens that changes a focus position based on a focus position change signal input from outside.
The illumination device according to claim 4, wherein the focal position change signal is information relating to an imaging range input from the imaging device.