JP6946941B2 - Lighting device - Google Patents

Description

The present disclosure relates to a lighting device using coherent light.

A lighting device that illuminates an illuminated area with light diffracted by an optical element such as a hologram element is known (see Patent Document 1). In Patent Document 1, a laser beam is used as an illumination light source, and a scanning unit such as a MEMS (Micro Electro Mechanical Systems) mirror is provided to scan the laser beam on the optical element. If the scanning unit is provided, the cost is increased and it becomes difficult to miniaturize the lighting device. In addition, the scanning unit must scan the laser beam at high speed, which leads to an increase in power consumption.

Further, Patent Document 1 discloses a technique in which a laser beam is passed / blocked for each small region by an optical shutter unit instead of providing a scanning unit. When the light in the small region is blocked by the optical shutter unit, the amount of light passing through the optical shutter unit is reduced by that amount, and the illumination intensity in the illuminated area is reduced.

On the other hand, Patent Document 2 discloses a technique for controlling the traveling direction of laser light using a KTN crystal element. In Patent Document 2, a laser beam whose traveling direction is controlled by a KTN liquid crystal element is projected onto a screen via a condenser lens, an electro-optical element, and a projection lens.

Japanese Patent No. 6094920 Japanese Unexamined Patent Publication No. 2008-175869

In Patent Document 2, the traveling direction of the laser beam is controlled by the KTN liquid crystal element for the purpose of reducing scintillation (speckle), and the laser beam whose traveling direction is controlled by the KTN liquid crystal element is used for screen illumination. I only keep in mind to use it. Further, in the KTN liquid crystal element, there is no guarantee that the traveling direction of the laser beam can be controlled accurately. Patent Document 2 does not disclose or suggest a specific configuration for preventing illumination blurring on the screen.

The problem to be solved by the present disclosure is to provide a lighting device that can be miniaturized, can reduce power consumption, and can finely control the traveling direction of coherent light.

In order to solve the above problems, in one aspect of the present disclosure, a light source that emits coherent light and a light source are used.
An optical control member that controls the traveling direction of coherent light,
An optical element that diffracts coherent light emitted from the light control member to illuminate an illuminated area is provided.
The optical control member has a plurality of half-wavelength switching elements and a plurality of liquid crystal polarizing elements that are alternately laminated.
The half-wavelength switching element can electrically switch whether the incident light is emitted with the phase of the incident light shifted by half a wavelength or the incident light is emitted without shifting the phase.
The liquid crystal polarizing element electrically diffracts the incident light in a positive or negative primary direction depending on the direction of rotation of the circularly polarized light of the incident light, or emits the incident light without changing the polarization state. Can be switched
The optical control member electrically controls each of the plurality of liquid crystal polarizing elements and each of the plurality of half-wavelength switching elements individually to electrically control the coherent light incident on the optical control member. A lighting device that controls the direction of travel is provided.

In another aspect of the present disclosure, a light source that emits coherent light and
An optical element that diffracts coherent light emitted from the light source,
An optical control member that controls the traveling direction of coherent light diffracted by the optical element to illuminate an illuminated area is provided.
The optical control member has a plurality of half-wavelength switching elements and a plurality of liquid crystal polarizing elements that are alternately laminated.
The half-wavelength switching element can electrically switch whether the incident light is emitted with the phase of the incident light shifted by half a wavelength or the incident light is emitted without shifting the phase.
The liquid crystal polarizing element electrically diffracts the incident light in a positive or negative primary direction depending on the direction of rotation of the circularly polarized light of the incident light, or emits the incident light without changing the polarization state. Can be switched
The optical control member electrically controls each of the plurality of liquid crystal polarizing elements and each of the plurality of half-wavelength switching elements individually to electrically control the coherent light incident on the optical control member. A lighting device that controls the direction of travel is provided.

Each of the plurality of half-wavelength switching elements switches whether or not to reverse the direction of rotation of the circularly polarized light of the coherent light emitted from the liquid crystal polarizing elements arranged adjacent to each other.
Each of the plurality of liquid crystal polarizing elements has positive or negative primary directions depending on the direction of rotation of the circularly polarized light of the coherent light emitted from the half-wavelength switching elements arranged adjacent to each other. May be diffracted.

A voltage control unit for individually controlling the voltage applied to each of the plurality of half-wavelength switching elements and individually controlling the voltage applied to each of the plurality of liquid crystal polarizing elements is provided.
Even if the coherent light incident on the optical control member is controlled by the voltage control of the voltage control unit, the traveling direction is controlled each time the coherent light passes through the stacked individual half-wavelength switching elements and the liquid crystal polarizing elements in order. good.

The optical element has a plurality of element diffusion regions and has a plurality of element diffusion regions.
Each of the plurality of element diffusion regions may diffuse incident light to illuminate at least a part of the illuminated area, or may display predetermined information in at least a part of the illuminated area.

Each of the plurality of element diffusion regions may have a unique diffusion characteristic with respect to the incident light.

The optical element is a hologram element having a plurality of element holograms.
Each of the plurality of element holograms may include interference fringes having unique diffraction characteristics.

A shaping optical system that shapes the coherent light emitted from the light source and causes it to enter the light control member or the optical element may be provided.

According to the present disclosure, it is possible to reduce the size and power consumption, and to finely control the traveling direction of coherent light.

The figure which shows the schematic structure of the lighting apparatus by one Embodiment of this disclosure. Sectional drawing of an optical control member. The figure which shows typically how the hologram element illuminates the illuminated area. The figure which shows the relationship between the beam diameter of a laser beam and the size of each element hologram in a hologram element. FIG. 1 is a diagram in which the positional relationship between the optical control member and the optical element is reversed.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the convenience of illustration and comprehension.

Furthermore, as used in the present specification, the terms such as "parallel", "orthogonal", and "identical" and the values of length and angle that specify the shape and geometric conditions and their degrees are strictly referred to. Without being bound by meaning, we will interpret it including the range in which similar functions can be expected.

FIG. 1 is a diagram showing a schematic configuration of a lighting device 1 according to an embodiment of the present disclosure. The lighting device 1 of FIG. 1 includes a light source 2, a shaping optical system 3, an optical control member 4, and an optical element 5.

The light source 2 emits coherent light. Here, the coherent light is light having the same wavelength and frequency, and is typically laser light. Hereinafter, the coherent light emitted from the light source 2 is referred to as a laser beam. The light source 2 may emit laser light in a single wavelength range, or may emit laser light in a plurality of wavelength ranges (for example, three wavelength ranges of red, green, and blue). Strictly speaking, laser light in a plurality of wavelength ranges is emitted from different light sources 2, but for simplification of illustration, only one light source 2 is shown in FIG.

The shaping optical system 3 shapes the laser beam emitted from the light source 2. In other words, the shaping optical system 3 shapes the shape of the cross section orthogonal to the optical axis of the laser beam and the three-dimensional shape of the luminous flux of the laser beam. In one specific example, the shaping optical system 3 shapes the laser beam emitted from the light source 2 into a widened parallel light beam. The shaping optical system 3 of FIG. 1 has a lens 31 and a collimating lens 32 in the order along the optical path of the laser beam. The lens 31 shapes the laser beam emitted from the light source 2 into a divergent luminous flux. The collimating lens 32 shapes the divergent luminous flux generated by the lens 31 into a parallel luminous flux. The laser beam parallelized by the collimating lens 32 is incident on the light control member 4.

The shaping optical system 3 is not an essential component and may be omitted. When the shaping optical system 3 is omitted, the laser light emitted from the light source 2 is incident on the optical control member 4. For example, when the function of collimating the laser beam is provided inside the light source 2, it is not necessary to provide the shaping optical system 3 separately from the light source 2. Hereinafter, an example including the shaping optical system 3 will be described.

The light control member 4 controls the traveling direction of the laser beam shaped (colimated) by the shaping optical system 3. As shown in the cross-sectional structure of FIG. 2, the optical control member 4 has a plurality of half-wavelength switching elements 4a and a plurality of liquid crystal polarizing elements 4b that are alternately laminated.

The half-wavelength switching element 4a can electrically switch whether the incident light is emitted with the phase of the incident light shifted by half a wavelength or the incident light is emitted without shifting the phase. The half-wavelength switching element 4a can electrically switch whether or not to reverse the direction of rotation of the circularly polarized light of the coherent light emitted from the liquid crystal polarizing elements 4b arranged adjacent to each other.

The liquid crystal polarizing element 4b electrically switches whether to diffract the incident light in the positive or negative primary direction according to the direction of rotation of the circularly polarized light of the incident light or to emit the incident light without changing the polarization state. It is possible. The liquid crystal polarizing element 4b can diffract the coherent light in the positive or negative primary direction according to the direction of rotation of the circularly polarized light of the coherent light emitted from the adjacent half-wavelength switching elements 4a. ..

A voltage control unit 6 is connected to the plurality of half-wavelength switching elements 4a and the plurality of liquid crystal polarizing elements 4b. The voltage control unit 6 individually controls the voltage applied to each of the plurality of half-wavelength switching elements 4a, and individually controls the voltage applied to each of the plurality of liquid crystal polarizing elements 4b. More specifically, the half-wavelength switching element 4a reverses the direction of rotation of circularly polarized light when a predetermined voltage is applied by the voltage control unit 6, and changes the polarization state of the incident light when the voltage is no longer applied. Make it transparent without changing it. Further, the liquid crystal polarizing element 4b diffracts circularly polarized light in the positive primary or negative primary direction when a predetermined voltage is applied by the voltage control unit 6, and when the voltage is no longer applied, the polarized light is polarized. Make it transparent without changing the state. By the voltage control of the voltage control unit 6, the traveling direction of the laser light incident on the optical control member 4 is controlled each time it passes through the stacked individual half-wavelength switching elements 4a and the liquid crystal polarizing element 4b in order.

In this way, the laser beam incident on the optical control member 4 can control the traveling direction each time it passes through the stacked individual half-wavelength switching elements 4a and the liquid crystal polarizing element 4b, so that the half-wavelength switching element As the number of layers of 4a and the liquid crystal polarizing element 4b increases, the traveling direction of the laser beam can be changed within a larger range. The beam diameter of the laser beam emitted from the optical control member 4 changes according to the voltage applied by the voltage control unit 6 to the individual half-wavelength switching elements 4a and the liquid crystal polarizing element 4b, and in some cases, the optical control member 4 A laser beam having a beam diameter larger than the beam diameter of the laser beam incident on the light control member 4 may be emitted, or a laser beam having a beam diameter smaller than the beam of the laser beam incident on the optical control member 4 may be emitted. It is possible.

As described above, the optical control member 4 can scan the laser beam in the two-dimensional direction, and can arbitrarily change the beam diameter of the laser beam. Since the optical control member 4 scans the laser beam by electrical control by the voltage control unit 6, it does not have a mechanical mechanism as in the case of mechanically moving the optical mirror to scan the laser beam. As a result, miniaturization and low power consumption are possible, and problems such as wear do not occur, so maintainability is improved.

The laser beam emitted from the light control member 4 is incident on the optical element 5. The optical element 5 diffracts the laser beam emitted from the light control member 4 to illuminate the illuminated region 7. Here, the illumination is not only a case where at least a part of the illuminated area 7 is illuminated with a uniform illumination intensity, but also a case where some information is displayed by a laser beam in at least a part of the illuminated area 7. included. Information is characters, symbols, numbers, patterns, patterns, images, etc., and the specific content of the information does not matter. Information is displayed on the illuminated area 7 for, for example, for the purpose of giving design and decoration, for calling attention to surrounding people, for the purpose of displaying guidance, for the purpose of advertising, and the like. Further, the information display may be a single color (monochrome) or a plurality of colors (color).

As shown in FIG. 3 described later, the optical element 5 may be composed of a plurality of element diffusion regions 5a. The individual element diffusion regions 5a have individual diffusion characteristics. Of the plurality of element diffusion areas 5a, some element diffusion areas 5a are provided for the purpose of illuminating the illuminated area 7, and the remaining element diffusion areas 5a are provided for the purpose of displaying some information in the illuminated area 7. May be done. The laser beam diffused in each element diffusion region 5a for the purpose of illumination may illuminate at least a part of the illuminated region 7 in an overlapping manner, or may illuminate different locations in the illuminated region 7. good. Further, each element diffusion region 5a for the purpose of displaying information may display some information in different places in the illuminated region 7.

The optical element 5 can be composed of, for example, a hologram element 8 using a hologram recording medium. Interference fringes are formed in the hologram element 8, and the incident light on the hologram element 8 is interfered with by the interference fringes and diffracted in a predetermined direction, and the illuminated region 7 is illuminated by the diffracted light.

The hologram element 8 may be divided into a plurality of element holograms. Interference fringes are formed on each element hologram and have individual diffraction characteristics. As a result, the laser light diffracted by the individual element holograms can illuminate the same region in the illuminated region 7 in an overlapping manner, or can illuminate different regions. Further, the illumination range of the laser beam diffracted by the individual element holograms can be arbitrarily set.

FIG. 3 is a diagram schematically showing how a hologram element 8 having a plurality of element holograms 8a illuminates an illuminated area 7. A part of the element hologram 8a in the hologram element 8 of FIG. 3 is provided to illuminate at least a part in the illuminated area 7, and the other element hologram 8a sends some information to a part in the illuminated area 7. It is provided for display. Each element hologram 8a for the purpose of illumination may illuminate the same area in the illuminated area 7 in an overlapping manner, or may illuminate different areas. Further, the size of the range illuminated by each element hologram 8a may be the same or different. On the other hand, each element hologram 8a for the purpose of displaying information may display different information at different places in the illuminated area 7, or a plurality of element holograms 8a jointly form one piece of information to be covered. It may be displayed at a predetermined place in the illumination area 7.

The color for illuminating the illuminated area 7 or displaying information is arbitrary. For example, when the optical control member 4 emits laser light in a plurality of wavelength ranges, the wavelength range of the laser light and the element hologram 8a are associated with each other. The laser light in a specific wavelength range may be incident on the specific element hologram 8a. Since the optical control member 4 can control the traveling direction of the laser beam by the voltage control of the voltage control unit 6, it is also possible to make the laser beam in a specific wavelength range incident on the corresponding element hologram 8a. It is possible by voltage control.

The element hologram 8a can be produced, for example, by using scattered light from an actual scattering plate as object light. More specifically, when the hologram photosensitive material, which is the base of the element hologram 8a, is irradiated with reference light and object light composed of coherent light having mutual interference, interference fringes due to the interference of these lights become the hologram photosensitive material. It is formed to produce the element hologram 8a. As the reference light, laser light which is coherent light is used, and as the object light, for example, scattered light from an inexpensively available isotropic scattering plate is used.

By irradiating the element hologram 8a with a laser beam so as to travel in the opposite direction in the optical path of the reference light used when the element hologram 8a is produced, it becomes the source of the object light used when the element hologram 8a is produced. A reproduced image of the scattering plate is generated at the arrangement position of the scattering plate. If the scattering plate that is the source of the object light used when producing the element hologram 8a has uniform surface scattering, the reproduced image of the scattering plate obtained by the element hologram 8a also has uniform surface illumination. The region where the reproduced image of the scattering plate is generated can be the illuminated region 7.

Further, the complex interference fringe pattern formed on each element hologram 8a should be reproduced along with the wavelength and incident direction of the planned reproduction illumination light instead of being formed by using the actual object light and the reference light. It is possible to design using a computer based on the shape and position of the image. The element hologram 8a thus obtained is also called a computer-generated hologram (CGH). For example, when the lighting device 1 is used to illuminate an illuminated area 7 having a certain size on the ground or water surface, it is difficult to generate object light, and a computer composite hologram is used as an element hologram 8a. It is preferable to use as.

Further, a Fourier transform hologram having the same diffusion angle range at each point on each element hologram 8a may be formed by computer synthesis. Further, an optical member such as a lens may be provided on the downstream side of the hologram element 8 so that the diffracted light is incident on the entire area of the illuminated region 7.

One of the advantages of using the hologram element 8 is that the light energy density of the light from the light source 2, for example, the laser light can be reduced by diffusion. Further, one of the other advantages is that the element hologram 8a can be used as a directional surface light source 2, so that the same illuminance distribution can be achieved as compared with the conventional lamp light source 2 (point light source 2). It is possible to reduce the brightness on the two light sources. As a result, even when the laser light source 2 is used as the light source 2, it is possible to contribute to the improvement of the safety of the laser light, and even if the laser light is directly viewed by the human eye from within the illuminated area 7, the single point light source 2 Compared to looking directly at the laser, there is less risk of adverse effects on the human eye.

On the other hand, the advantage of configuring the hologram element 8 with a plurality of element holograms 8a is that the edges are sharp when illuminating the illuminated area 7, especially the illuminated area 7 within a finite distance, as will be described in detail later. It is a point that can be done. If the hologram element 8 is a single Fourier type hologram, blurring corresponding to the size of the area of the hologram occurs in the illuminated area 7. In the present embodiment, it is possible to design the diffraction characteristics of each element hologram 8a in consideration of the positional relationship with the illuminated area 7, and the sharpness of the edge can be remarkably improved. That is, by including a plurality of element holograms 8a having different diffraction characteristics in one hologram element 8, it is possible to illuminate the illuminated area 7 while sharpening the edges. It should be noted that producing a single Fresnel-type hologram by photographing is restricted due to the difficulty of preparing object light, and producing a single Fresnel-type computer composite hologram is a hologram. It means that the calculation is performed over the entire area, and there are substantial restrictions from the viewpoint of the amount of calculation.

Further, when coherent light typified by laser light is used, there arises a problem of generation of speckle, as disclosed in WO2012 / 034174, for example. Speckles are perceived as speckled patterns and can cause physiological discomfort. When the hologram element 8 includes the plurality of element holograms 8a, the speckle patterns generated corresponding to the diffracted light from each element hologram 8a are overlapped and averaged in the illuminated region 7 and observed by the observer. It will be. As a result, the speckle can be made inconspicuous in each element illuminated area.

The specific form of the element hologram 8a may be a volumetric hologram recording medium using a photopolymer, a volumetric hologram recording medium of a type recording using a photosensitive medium containing a silver salt material, or a relief. A type (embossed type) hologram recording medium may be used.

FIG. 4 is a diagram showing the relationship between the beam diameter 8b of the laser beam emitted from the optical control member 4 and the size of each element hologram 8a in the hologram element 8. As described above, the beam diameter 8b of the laser light emitted from the light control member 4 may be larger than the beam diameter 8b of the incident light on the light control member 4. Therefore, the beam diameter 8b of the laser beam emitted from the light control member 4 and incident on the hologram element 8 may span a plurality of element holograms 8a as shown in FIG. If the hologram element 8 is not divided into a plurality of element holograms 8a, the hologram element 8 has a large area because interference fringes are formed on the premise that a laser beam having a beam diameter of a small area is incident. When a laser beam having a beam diameter is incident, the vicinity of the edge of the illumination range tends to be blurred, which causes illumination blur. On the other hand, when the hologram element 8 is divided into a plurality of element holograms 8a as shown in FIG. 4, each element hologram 8a diffracts the incident light by individual interference fringes, so that the plurality of element holograms 8a Even if the laser beam is incident so as to straddle, each element hologram 8a diffracts the incident light according to a predetermined diffraction characteristic. As a result, the illumination blur of the illuminated area 7 can be reduced.

In FIG. 1, the laser beam emitted from the optical control member 4 is incident on the optical element 5, and the illuminated area 7 is illuminated by the laser beam emitted from the optical element 5. As shown in FIG. The positional relationship between the optical control member 4 and the optical element 5 may be reversed.

In the lighting device 1 of FIG. 5, a laser beam shaped by the shaping optical system 3 is incident on the optical element 5. As described above, the optical element 5 is divided into, for example, a plurality of element diffusion regions 5a, and each element diffusion region 5a diffuses incident light with individual diffusion characteristics. The laser beam diffused by the optical element 5 is incident on the light control member 4. The optical control member 4 controls the traveling direction of the incident light by controlling whether or not the voltage control unit 6 applies a predetermined voltage to the individual half-wavelength switching elements 4a and the liquid crystal polarizing element 4b. A part of the laser light emitted from the light control member 4 illuminates the illuminated area 7, and the remaining laser light displays information in a predetermined range in the illuminated area 7.

Like the lighting device 1 of FIG. 1, the lighting device 1 of FIG. 5 can clearly illuminate the illuminated area 7, and can display arbitrary information in the illuminated area 7. However, if the polarization state of the laser beam changes while passing through the optical element 5, desired circularly polarized light cannot be obtained inside the optical control member 4, and the traveling direction of the laser beam is changed inside the optical control member 4. You may lose control as intended. Therefore, in the illumination device 1 of FIG. 5, the polarization state is prevented from changing while the laser beam passes through the optical element 5, or if the polarization state changes, it is desired in the optical element 5 accordingly. It is desirable to provide a layer that adjusts the polarization state so that circularly polarized light can be obtained.

As described above, the lighting device 1 according to the present embodiment includes an optical control member 4 capable of finely electrically controlling the traveling direction of the laser beam from the light source 2, and the traveling direction is controlled by the optical control member 4. The laser beam is incident on the optical element 5. Since the optical element 5 is composed of, for example, a hologram element 8 composed of a plurality of element holograms 8a, the diffraction direction of the laser light emitted from the optical control member 4 is individually determined for each element hologram 8a on which the laser light is incident. Can be controlled. As a result, the entire area of the illuminated area 7 can be clearly illuminated without illumination blurring, an arbitrary range within the illuminated area 7 can be clearly illuminated with an arbitrary color, and further, the inside of the illuminated area 7 can be clearly illuminated. It is also possible to display arbitrary information in an arbitrary color in an arbitrary place.

The light control member 4 electrically controls the traveling direction of the laser light from the light source 2, and does not block a part of the incident light unlike the liquid crystal shutter. Therefore, the light source 2 emits the laser light. Since the utilization efficiency can be improved, the illumination intensity of the illuminated area 7 can be increased, and the light intensity of the light source 2 does not need to be increased unnecessarily, the power consumption can be reduced.

Further, since the optical control member 4 is a laminated body in which half-wavelength switching elements 4a and liquid crystal polarizing elements 4b are alternately laminated, it can be made lighter, thinner, shorter, and smaller than mechanically scanning laser light with a MEMS mirror or the like. Also, since it does not have mechanical contacts, it is hard to break and maintainability is improved.

Further, although there is a problem that the emitted light of the optical control member 4 has a large beam diameter, the optical element 5 composed of the hologram element 8 and the like is divided into element diffusion regions 5a, and the diffusion characteristics are individually provided for each element diffusion region 5a. By providing the above, it is possible to clearly illuminate the vicinity of the edge of the illumination range in the illuminated area 7, and it is possible to display various information in the illuminated area 7 by a fine line drawing.

The aspects of the present disclosure are not limited to the individual embodiments described above, but also include various modifications that can be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the contents described above. That is, various additions, changes and partial deletions are possible without departing from the conceptual idea and purpose of the present disclosure derived from the contents defined in the claims and their equivalents.

1 Lighting device, 2 Light source, 3 Orthopedic optical system, 4 Light control member, 4a Half-wavelength switching element, 4b Liquid crystal polarizing element, 5 Optical element, 5a element diffusion region, 6 Voltage control unit, 7 Illuminated region, 8 Hologram element , 8a element hologram

Claims (8)

A light source that emits coherent light and
An optical control member that controls the traveling direction of coherent light,
An optical element that diffracts coherent light emitted from the light control member to illuminate an illuminated area is provided.
The optical control member has a plurality of half-wavelength switching elements and a plurality of liquid crystal polarizing elements that are alternately laminated.
The half-wavelength switching element can electrically switch whether the incident light is emitted with the phase of the incident light shifted by half a wavelength or the incident light is emitted without shifting the phase.
The liquid crystal polarizing element electrically diffracts the incident light in a positive or negative primary direction depending on the direction of rotation of the circularly polarized light of the incident light, or emits the incident light without changing the polarization state. Can be switched
The optical control member electrically controls each of the plurality of liquid crystal polarizing elements and each of the plurality of half-wavelength switching elements individually to electrically control the coherent light incident on the optical control member. A lighting device that controls the direction of travel. A light source that emits coherent light and
An optical element that diffracts coherent light emitted from the light source,
An optical control member that controls the traveling direction of coherent light diffracted by the optical element to illuminate an illuminated area is provided.
The optical control member has a plurality of half-wavelength switching elements and a plurality of liquid crystal polarizing elements that are alternately laminated.
The half-wavelength switching element can electrically switch whether the incident light is emitted with the phase of the incident light shifted by half a wavelength or the incident light is emitted without shifting the phase.
The liquid crystal polarizing element electrically diffracts the incident light in a positive or negative primary direction depending on the direction of rotation of the circularly polarized light of the incident light, or emits the incident light without changing the polarization state. Can be switched
The optical control member electrically controls each of the plurality of liquid crystal polarizing elements and each of the plurality of half-wavelength switching elements individually to electrically control the coherent light incident on the optical control member. A lighting device that controls the direction of travel. Each of the plurality of half-wavelength switching elements switches whether or not to reverse the direction of rotation of the circularly polarized light of the coherent light emitted from the liquid crystal polarizing elements arranged adjacent to each other.
Each of the plurality of liquid crystal polarizing elements has the coherent light in a positive or negative primary direction depending on the direction of rotation of the circularly polarized light of the coherent light emitted from the half-wavelength switching elements arranged adjacent to each other. The lighting device according to claim 1 or 2, wherein the light is diffracted. A voltage control unit for individually controlling the voltage applied to each of the plurality of half-wavelength switching elements and individually controlling the voltage applied to each of the plurality of liquid crystal polarizing elements is provided.
By the voltage control of the voltage control unit, the traveling direction of the coherent light incident on the optical control member is controlled each time it passes through the stacked individual half-wavelength switching elements and the liquid crystal polarizing elements in order. The lighting device according to any one of claims 1 to 3. The optical element has a plurality of element diffusion regions and has a plurality of element diffusion regions.
Each of the plurality of element diffusion regions diffuses incident light to illuminate at least a part of the illuminated area, or displays predetermined information in at least a part of the illuminated area. The lighting device according to any one of 4. The lighting device according to claim 5, wherein each of the plurality of element diffusion regions has a diffusion characteristic peculiar to incident light. The optical element is a hologram element having a plurality of element holograms.
The lighting device according to claim 5 or 6, wherein each of the plurality of element holograms includes interference fringes having unique diffraction characteristics. The lighting device according to any one of claims 1 to 7, further comprising a shaping optical system that shapes the coherent light emitted from the light source and causes the coherent light to be incident on the light control member or the optical element.

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