JP2007171745A - Illuminator and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator and a projector which eliminate a need of mechanical driving parts and are capable of sufficiently reducing the occurrence of speckles. <P>SOLUTION: The illuminator includes a laser light source for supplying laser light and a polymer dispersed liquid crystal part 13 having liquid crystal molecules 24 dispersed in a polymer member layer 25 having a polymer member and has the polymer dispersed liquid crystal part 13 disposed in an incidence position of the laser light and superposes laser light beams from the polymer dispersed liquid crystal part 13, which are emitted at each time of changing alignment of the liquid crystal molecules 24, to illuminate an illumination object. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a lighting device and a projector, and more particularly to a technology of a lighting device using laser light.

In recent years, projectors and displays using laser light sources have been proposed with the increase in output of semiconductor lasers and the development of blue semiconductor lasers. Since the laser beam has a single wavelength, it has characteristics such as high color purity, high coherence, and easy shaping. The laser light source has advantages such as being small in size and capable of instantaneous lighting as compared with a conventionally used metal halide lamp or halogen lamp. For this reason, it is expected to display a high-quality image with a small configuration by using laser light. Since the laser light has high coherence, a so-called speckle pattern in which bright spots and dark spots are randomly distributed in the irradiation region is likely to be generated. When speckle is generated in the laser beam enlarged and shaped to display an image, a glimmering flickering feeling is given to an observer, and the image viewing is adversely affected. A technique for reducing speckle is proposed in Patent Document 1, for example.

Japanese Patent Laid-Open No. 6-208089

In the technique of Patent Document 1 in which the speckle pattern is changed by rotation and vibration of the diffusion element,
A mechanical drive unit for driving the diffusing element such as a motor is required. By using such a drive unit, it is considered that the reliability of the apparatus is reduced, the apparatus is enlarged, and the quietness is deteriorated. Further, since the diffusion element is rotated by an external force, the diffusion element needs to have high durability, and the cost may be increased. When the diffusing element is simply reciprocated, there is a moment when the diffusing element stops, so that the effect of making it difficult to recognize a specific speckle pattern by superimposing various speckle patterns is reduced. Furthermore, since the same speckle pattern is periodically generated even if the diffusing element having the specific diffusing pattern is rotated and vibrated, it is conceivable that the observer recognizes the specific speckle pattern. As described above, according to the conventional technique, there is a problem that a mechanical driving unit is unnecessary and it is difficult to sufficiently reduce the generation of speckle. The present invention has been made in view of the above-described problems, and an object thereof is to provide an illumination device and a projector that do not require a mechanical drive unit and can sufficiently reduce speckle generation. To do.

In order to solve the above-described problems and achieve the object, according to the present invention, a laser light source that supplies laser light, and a polymer-dispersed liquid crystal portion in which liquid crystal molecules are dispersed in a layer of a polymer member, A polymer-dispersed liquid crystal unit is provided at a position where laser light is incident, and illuminates an illumination target by superimposing laser light from the polymer-dispersed liquid crystal unit every time the orientation of liquid crystal molecules is changed. Can be provided.

Polymer-dispersed liquid crystal (PDLC) changes the orientation of liquid crystal molecules dispersed in a polymer according to a pattern of voltage application. By changing the orientation of the liquid crystal molecules, the scattering characteristics of the laser light from the polymer-dispersed liquid crystal portion are changed. The speckle pattern of the laser beam can be changed by changing the scattering characteristic of the laser beam. By superimposing various speckle patterns while changing the orientation of liquid crystal molecules, it is possible to make it difficult to recognize a specific speckle pattern, and to effectively reduce speckle. Further, by using the polymer-dispersed liquid crystal unit, it is possible to reduce speckle without using a mechanical drive unit such as a motor. As a result, it is possible to obtain an illuminating device that eliminates the need for a mechanical drive and can sufficiently reduce the generation of speckle. By eliminating the need for a mechanical drive unit, it is possible to obtain a lighting device having a small size, low power, low cost, high silence, and high reliability.

Moreover, as a preferable aspect of the present invention, the polymer-dispersed liquid crystal part includes a first state in which the laser light from the polymer-dispersed liquid crystal part is scattered, and a second state in which the scattering of the laser light is reduced compared to the first state. It is desirable to change repeatedly. By repeatedly changing the polymer-dispersed liquid crystal portion between the first state and the second state, the speckle pattern can be constantly changed, making it difficult for an observer to recognize a specific speckle pattern.

As a preferred embodiment of the present invention, the polymer dispersed liquid crystal part repeats the first state and the second state by repeatedly applying a voltage to the polymer dispersed liquid crystal part and stopping the application of the voltage. It is desirable to change. In the case of using liquid crystal molecules whose properties are aligned by applying a voltage, the first state can be obtained by stopping the application of the voltage, and the second state can be obtained by applying the voltage. In the case of using liquid crystal molecules whose properties are aligned by stopping the application of voltage, the first state can be obtained by applying voltage, and the second state can be obtained by stopping applying voltage. Thereby, the polymer-dispersed liquid crystal part can be repeatedly changed between the first state and the second state.

Further, as a preferred embodiment of the present invention, the polymer-dispersed liquid crystal part is configured such that when the liquid crystal molecules are aligned by applying a voltage to the polymer-dispersed liquid crystal part, the application of voltage is stopped in the first state, and When a voltage lower than the maximum voltage at which the alignment of the liquid crystal molecules is substantially uniform in the state 2 is applied and the alignment of the liquid crystal molecules is aligned by stopping the application of the voltage to the polymer dispersed liquid crystal portion, It is desirable that a voltage is applied and a voltage lower than the applied voltage in the first state is applied in the second state. Laser light scattering is minimized when the orientation of the liquid crystal molecules in the polymer-dispersed liquid crystal portion is substantially uniform. In this aspect, in the second state, it is possible to obtain a state before the alignment of the liquid crystal molecules becomes substantially uniform. Since the liquid crystal molecules are randomly aligned before the alignment of the liquid crystal molecules becomes substantially uniform, the speckle pattern can be changed randomly. In addition, it is possible to make it difficult to recognize a specific speckle pattern, compared to the case where the alignment of liquid crystal molecules becomes substantially uniform every time the second state is reached. Thereby, speckles can be further reduced.

As a preferred embodiment of the present invention, the polymer-dispersed liquid crystal part may start changing to the first state before the time until the alignment of the liquid crystal molecules is maintained in the second state. desirable. The time until the orientation of the liquid crystal molecules is maintained is the response time until the orientation of the liquid crystal molecules becomes substantially uniform by applying a voltage to the polymer-dispersed liquid crystal portion in the second state or by stopping the application of the voltage. is there. The polymer-dispersed liquid crystal portion starts the change to the first state before the alignment of the liquid crystal molecules becomes substantially uniform in the second state. Since the liquid crystal molecules are randomly aligned before the alignment of the liquid crystal molecules becomes substantially uniform, the speckle pattern can be changed randomly. In addition, it is possible to make it difficult to recognize a specific speckle pattern, compared to the case where the alignment of liquid crystal molecules becomes substantially uniform every time the second state is reached. Thereby, speckles can be further reduced.

Moreover, as a preferable aspect of the present invention, it is desirable that the polymer-dispersed liquid crystal portion in the first state has a haze value of 5% to 20%. Thereby, the change of the shape of an irradiation area | region can be reduced and the reduction of a speckle can be aimed at.

Further, as a preferred embodiment of the present invention, a diffractive optical element that shapes an irradiation region of the laser light by diffracting the laser light is provided, and the polymer-dispersed liquid crystal unit is in the optical path between the diffractive optical element and the illumination target. It is desirable to be provided. By using the diffractive optical element, the irradiation region of the laser beam can be shaped according to the shape of the illumination target with a simple configuration. By using the diffractive optical element, the light quantity distribution can be made uniform. For example, when a polymer-dispersed liquid crystal unit is provided on the incident side of the diffractive optical element, it may be possible that shaping of the irradiation region becomes insufficient due to incident laser light having a disordered phase on the diffractive optical element. By adopting a configuration in which a polymer-dispersed liquid crystal unit is provided between the diffractive optical element and the object to be illuminated, it is possible to avoid phase disturbance on the incident side of the diffractive optical element and accurately shape the irradiation region.

Furthermore, according to the present invention, it is possible to provide a projector including the above-described illumination device. By using the lighting device described above, a mechanical drive unit for reducing speckles is not necessary, and generation of speckles can be sufficiently reduced. As a result, it is possible to obtain a projector that can display a high-quality image with reduced speckles, having a small size, low power, low cost, high silence, and high reliability.

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

FIG. 1 shows a schematic configuration of a lighting apparatus 10 according to Embodiment 1 of the present invention. The illumination device 10 has a laser light source 11 that supplies laser light. As the laser light source 11, a semiconductor laser can be used. The diffractive optical element 12 diffracts the laser light, thereby illuminating the object I.
The illumination area of the laser beam is shaped and enlarged to a rectangular shape in accordance with the shape. The diffractive optical element 12 also makes the light quantity distribution of the laser light uniform. As the diffractive optical element 12, for example, a computer generated hologram (CGH) can be used. The polymer-dispersed liquid crystal unit 13 is a position where laser light is incident, and is provided in the optical path between the diffractive optical element 12 and the illumination target I. The light transmitted through the polymer-dispersed liquid crystal unit 13 proceeds in the direction of the illumination target I. The laser light source 11 is a semiconductor laser pumped solid (DPSS).
) A laser, a solid-state laser, a liquid laser, a gas laser, or the like may be used.

FIG. 2 shows a schematic configuration of the main part of the polymer-dispersed liquid crystal unit 13. The polymer dispersed liquid crystal part 13 is
The liquid crystal molecules 24 are dispersed in a polymer member layer 25 having a polymer member.
The polymer-dispersed liquid crystal unit 13 employs a so-called microcapsule method in which particles 23 containing liquid crystal molecules 24 are dispersed in a polymer member layer 25. The polymer member layer 25 in which the particles 23 are dispersed can be formed, for example, by separating the polymer member and the liquid crystal molecules 24 by phase separation accompanying a polymerization reaction.

The polymer-dispersed liquid crystal unit 13 changes the alignment of the liquid crystal molecules 24 in accordance with a voltage application pattern. For example, the liquid crystal molecules 24 have a property of being oriented so as to face the direction of the electric field when a voltage is applied to the polymer dispersed liquid crystal portion 13. The first electrode 26 is formed on one side of the polymer member layer 25, for example, the incident side. The second electrode 27 is formed on the side of the polymer member layer 25 opposite to the side on which the first electrode 26 is formed, for example, on the emission side.

A power supply unit 28 is connected to the first electrode 26 and the second electrode 27. First electrode 26
The second electrode 27 applies a voltage to the polymer member layer 25 in which the liquid crystal molecules 24 are dispersed in the polymer dispersed liquid crystal part 13. The 1st electrode 26 and the 2nd electrode 27 can be comprised by ITO and IZO which are metal oxides, for example. The first electrode 26, the polymer member layer 25, and the second electrode 27 are sandwiched between the incident side transparent substrate 21 and the emission side transparent substrate 22.

FIG. 3 illustrates a first state in which the application of voltage to the polymer-dispersed liquid crystal unit 13 is stopped. When the application of voltage to the polymer dispersed liquid crystal part 13 is stopped, the liquid crystal molecules 24 are in a random alignment state. The polymer member layer 25 is formed so that the polymer member and the particles 23 have different refractive indexes when the liquid crystal molecules 24 are in a random alignment state. When the polymer member and the particle 23 have different refractive indexes, the light incident on the polymer member layer 25 is scattered by refraction at the interface between the polymer member and the particle 23. in this way,
The polymer-dispersed liquid crystal unit 13 stops the application of the voltage, whereby the polymer-dispersed liquid crystal unit 1
3 is scattered. Further, when the application of voltage to the polymer-dispersed liquid crystal unit 13 is stopped, the scattering of the laser beam is maximized.

FIG. 4 illustrates a second state in which the alignment of the liquid crystal molecules 24 is aligned by applying a voltage to the polymer dispersed liquid crystal portion 13. The polymer member layer 25 includes liquid crystal molecules 24.
When the orientation of the liquid crystal molecules 24 is aligned, the difference between the refractive index of the polymer member and the refractive index of the particles 23 becomes smaller than when the liquid crystal molecules 24 are in a random orientation state. By reducing the difference between the refractive index of the polymer member and the refractive index of the particles 23, light scattering in the polymer member layer 25 is suppressed more than when the liquid crystal molecules 24 are in a random alignment state. Thus, the polymer-dispersed liquid crystal unit 13 emits laser light with reduced scattering by aligning the orientation of the liquid crystal molecules 24 by applying a voltage. Further, when the voltage applied to the polymer-dispersed liquid crystal portion 13 is the maximum voltage, the alignment of the liquid crystal molecules 24 becomes substantially uniform, so that the laser light scattering is minimized.

By repeating the application of the voltage and the stop of the application of the voltage, the polymer-dispersed liquid crystal unit 13 repeatedly changes between the first state and the second state. By changing the orientation of the liquid crystal molecules 24, the scattering characteristics of the laser light from the polymer-dispersed liquid crystal portion 13 are changed. The speckle pattern of the laser beam can be changed by changing the scattering characteristic of the laser beam. Thus, the illuminating device 10 includes the polymer-dispersed liquid crystal unit 13 each time the orientation of the liquid crystal molecules 24 is changed.
The generation of speckles is reduced by illuminating the illumination target I by superimposing the laser beam from. By superimposing various speckle patterns while changing the orientation of liquid crystal molecules, it is possible to make it difficult to recognize a specific speckle pattern, and to effectively reduce speckle. Further, by repeatedly changing the polymer-dispersed liquid crystal unit 13 between the first state and the second state, the speckle pattern can be constantly changed, making it difficult for the observer to recognize a specific speckle pattern. .

Switching between application of voltage to the polymer-dispersed liquid crystal unit 13 and stop of application of voltage is, for example, 1
It is desirable to perform 60 times or more per second. As a result, it is possible to change the speckle pattern faster than a human recognizes a specific speckle pattern, and it is possible to sufficiently reduce the generation of speckle. The polymer-dispersed liquid crystal unit 13 desirably has a haze value in the first state in which laser light is dispersed of 5% to 20%. This
A change in the shape of the irradiation region once shaped by the diffractive optical element 12 can be reduced, and speckle can be reduced.

The illumination device 10 can reduce speckles by using the polymer-dispersed liquid crystal unit 13 without using a mechanical drive unit such as a motor. Thereby, there is an effect that a mechanical drive unit is not required and the generation of speckle can be sufficiently reduced. By eliminating the need for a mechanical drive unit, it is possible to obtain the lighting device 10 that is small in size, low in power, low in cost, high in silence, and high in reliability.

For example, when the polymer-dispersed liquid crystal unit 13 is provided on the incident side of the diffractive optical element 12, the laser beam having a disordered phase is incident on the diffractive optical element 12, so that the irradiation region is not shaped and the light quantity distribution is not uniform. It may be sufficient. For this reason, it is desirable that the polymer-dispersed liquid crystal unit 13 is provided in the optical path between the diffractive optical element 12 and the illumination target I as in this embodiment.
By providing the polymer-dispersed liquid crystal unit 13 on the exit side from the diffractive optical element 12, the disturbance of the phase on the incident side of the diffractive optical element 12 can be avoided, and the irradiation area can be accurately shaped and the light quantity distribution can be made uniform. It becomes possible. Furthermore, the polymer-dispersed liquid crystal unit 13 includes a diffractive optical element 12.
It is desirable to provide at a position close to the diffractive optical element 12 between the illumination object I and the illumination object I. Thereby, it is set as the structure which makes light enter into the polymer dispersion | distribution liquid crystal part 13 before an irradiation area | region is expanded as much as possible, and the polymer dispersion | distribution liquid crystal part 13 can be reduced in size. Note that a polymer-dispersed liquid crystal unit 13 may be provided between the laser light source 11 and the diffractive optical element 12 as long as the irradiation region can be shaped and the light amount distribution can be made uniform.

The polymer-dispersed liquid crystal unit 13 is not limited to the case where a voltage is applied so that the alignment of the liquid crystal molecules 24 is substantially uniform in the second state in which the scattering of the laser light is reduced. For example, as shown in FIG. 5, in the second state, a voltage lower than the maximum voltage V at which the alignment of the liquid crystal molecules 24 becomes substantially uniform, for example, a voltage V ′ corresponding to about 80% of the maximum voltage V is applied. It is also good. The polymer-dispersed liquid crystal unit 13 is applied with a rectangular wave voltage having a constant voltage V ′ during the time t. In this case, the polymer-dispersed liquid crystal part 13 is in a state before the alignment of the liquid crystal molecules 24 becomes substantially uniform in the second state.

Before the alignment of the liquid crystal molecules 24 becomes substantially uniform, the liquid crystal molecules 24 are randomly aligned. By aligning the liquid crystal molecules 24 at random, the speckle pattern can be changed at random. In addition, it is possible to make it difficult to recognize a specific speckle pattern, compared to the case where the alignment of liquid crystal molecules becomes substantially uniform every time the second state is reached.
Thereby, speckles can be further reduced. As shown in FIG. 6, the polymer-dispersed liquid crystal unit 13 may apply a sine wave voltage having a peak at the voltage V ′.

The polymer-dispersed liquid crystal portion 13 is not limited to the case where the liquid crystal molecules 24 whose properties are aligned by the application of voltage are used, and the liquid crystal molecules 24 whose properties are aligned when the voltage application is stopped may be used. In this case, the polymer-dispersed liquid crystal unit 13 can be in a first state in which laser light is dispersed by applying a voltage, and in a second state in which dispersion of laser light is reduced by stopping the application of voltage. Further, as shown in FIG. 7, the polymer dispersed liquid crystal portion 13 does not have a voltage zero at which the alignment of the liquid crystal molecules 24 becomes substantially uniform in the second state, but is a voltage lower than the maximum voltage V, for example, about the maximum voltage V. A voltage V ″ corresponding to 20% may be applied. In the first state, by setting the voltage applied to the polymer-dispersed liquid crystal unit 13 to the maximum voltage V, the liquid crystal molecules 24 are in a random alignment state, and the laser light scattering is maximized. The polymer-dispersed liquid crystal part 13 is in a state before the alignment of the liquid crystal molecules 24 becomes substantially uniform by applying a voltage lower than the maximum voltage V in the second state. Also in this case, speckle can be further reduced.

The state before the alignment of the liquid crystal molecules 24 becomes substantially uniform is not limited to the case where the voltage applied to the polymer-dispersed liquid crystal unit 13 is changed in the second state. The change to the first state may be started before the time until the alignment of the liquid crystal molecules 24 is maintained in the second state. The time until the orientation of the liquid crystal molecules 24 is maintained is the liquid crystal molecules 2 in the second state by applying a voltage to the polymer-dispersed liquid crystal unit 13 or stopping the application of the voltage.
4 is a response time until the orientation of 4 becomes substantially uniform.

For example, as shown in FIG. 8, it is assumed that the orientation of the liquid crystal molecules 24 is maintained substantially uniform by applying a voltage V to the polymer-dispersed liquid crystal portion 13 for a time t. In this case,
In the second state, the polymer-dispersed liquid crystal unit 13 is applied with the voltage V for a time shorter than the time t when the alignment of the liquid crystal molecules 24 becomes substantially uniform, for example, a time t ′ corresponding to about 80% of the time t. In this way, by adjusting the time during which the voltage is applied to the polymer-dispersed liquid crystal portion 13, the change to the first state is started in the previous stage where the alignment of the liquid crystal molecules 24 becomes substantially uniform in the second state.

Also in this case, since the liquid crystal molecules 24 are randomly aligned before the alignment of the liquid crystal molecules 24 becomes substantially uniform, the speckle pattern can be changed randomly.
In addition, it is possible to make it difficult to recognize a specific speckle pattern than when the alignment of the liquid crystal molecules 24 is aligned every time the second state is reached. Thereby, speckles can be further reduced.

FIG. 9 illustrates a lighting device according to a modification of the present embodiment. This variation is
Liquid crystal molecules 34 are dispersed in a polymer member 35 formed in a mesh shape in the three-dimensional direction.
A so-called polymer network type polymer dispersed liquid crystal portion 33 is used.
The first electrode 26 and the second electrode 27 apply a voltage to the polymer member 35 in which the liquid crystal molecules 34 are dispersed in the polymer dispersed liquid crystal part 33. The polymer-dispersed liquid crystal unit 33 is, for example, disclosed in
It can be produced using the production method described in Japanese Patent No. 333583.

For example, in the first state in which the application of voltage to the polymer dispersed liquid crystal portion 33 is stopped, the liquid crystal molecules 34 are in a random alignment state as shown in FIG. When the liquid crystal molecules 34 are in a random alignment state, the polymer-dispersed liquid crystal unit 33 scatters laser light. Further, in the second state in which a voltage is applied to the polymer dispersed liquid crystal part 33, the alignment of the liquid crystal molecules 34 is aligned as shown in FIG. By aligning the alignment of the liquid crystal molecules 34, the polymer-dispersed liquid crystal part 33 emits laser light with reduced scattering. Also in the case of this modification, the generation of speckle can be sufficiently reduced. Also in the case of this modification, a voltage may be applied so that the liquid crystal molecules 34 are in a state before the alignment is substantially uniform in the second state. In addition, the alignment of the liquid crystal molecules 34 is not limited to the alignment of the liquid crystal molecules 34 by applying a voltage, and the alignment of the liquid crystal molecules 34 may be aligned when the voltage application is stopped.

FIG. 11 shows a schematic configuration of the projector 100 according to the second embodiment of the invention. The projector 100 is a so-called front projection type projector that supplies light to a screen 65 provided on the viewer side and observes an image by observing light reflected by the screen 65. The projector 100 includes the color light illumination devices 10R, 10G, and 10B configured in the same manner as the illumination device 10 according to the first embodiment.

Laser light source 1 for R light provided in the illumination device 10R for red light (hereinafter referred to as “R light”).
1R supplies R light. The R light diffractive optical element 12R diffracts the R light from the R light laser light source 11R, thereby converting the illumination area of the R light and equalizing the light amount distribution. R
The R light from the light diffractive optical element 12R passes through the polymer dispersion liquid crystal part 13R for R light,
The light enters the R light spatial light modulation device 61R, which is the illumination target of the R light illumination device 10R. The spatial light modulator 61R for R light is a transmissive liquid crystal display device that modulates R light according to an image signal.
The R light modulated by the R light spatial light modulator 61R is incident on a cross dichroic prism 62 which is a color synthesis optical system.

Laser light source 1 for G light provided in an illumination device 10G for green light (hereinafter referred to as “G light”).
1G supplies G light. The G light diffractive optical element 12G diffracts the G light from the G light laser light source 11G, thereby converting the illumination area of the G light and making the light amount distribution uniform. G
G light from the diffractive optical element for light 12G passes through the polymer dispersed liquid crystal part 13G for G light,
The light enters the G light spatial light modulation device 61G, which is the illumination target of the G light illumination device 10G. The G light spatial light modulation device 61G is a transmissive liquid crystal display device that modulates G light according to an image signal.
The G light modulated by the G light spatial light modulator 61G is incident on the cross dichroic prism 62, which is a color synthesis optical system.

Laser light source 1 for B light provided in the illumination device 10B for blue light (hereinafter referred to as “B light”).
1B supplies B light. The diffractive optical element 12B for B light diffracts the B light from the laser light source 11B for B light, thereby converting the illumination area of the B light and making the light quantity distribution uniform. B
The B light from the light diffractive optical element 12B passes through the polymer dispersion liquid crystal part 13B for B light,
The light enters the spatial light modulation device 61B for B light, which is an illumination target of the illumination device for B light 10B. The spatial light modulator 61B for B light is a transmissive liquid crystal display device that modulates B light according to an image signal.
The B light modulated by the B light spatial light modulator 61B is incident on a cross dichroic prism 62 which is a color synthesis optical system.

The cross dichroic prism 62 has two dichroic films 62a and 62b arranged so as to be substantially orthogonal to each other. The first dichroic film 62a reflects R light,
Transmits G light and B light. The second dichroic film 62b reflects B light and transmits G light and R light. As described above, the cross dichroic prism 62 includes the spatial light modulators 61.
R light, G light, and B light modulated by R, 61G, and 61B are combined. Projection optical system 6
3 projects the light combined by the cross dichroic prism 62 onto the screen 65.

Since the projector 100 includes the color light illumination devices 10R, 10G, and 10B configured in the same manner as the illumination device 10 of the first embodiment, a mechanical driving unit for reducing speckles is unnecessary, and The generation of speckle can be sufficiently reduced. Accordingly, there is an effect that a high-quality image with reduced speckles can be displayed by a configuration having small size, low power, low cost, high silence, and high reliability.

The projector 100 is not limited to a so-called three-plate projector provided with three transmissive liquid crystal display devices, but may be a projector using one transmissive liquid crystal display device or a projector using a reflective liquid crystal display device, for example. good. In addition, the spatial light modulator 61R for each color light,
61G and 61B are not limited to a configuration using a liquid crystal display device, and may be a micromirror array device that drives micromirrors or a device that scans line-shaped modulated light in a one-dimensional direction. The projector 100 is not limited to a front projection type projector, and may be a so-called rear projector that supplies laser light to one surface of a screen and observes an image by observing light emitted from the other surface of the screen. good. Furthermore, the illumination device of the present invention may be applied to a slide projector or an exposure device.

As described above, the illumination device according to the present invention is suitable as an illumination device for displaying an image using laser light.

The figure which shows schematic structure of the illuminating device which concerns on Example 1 of this invention. The figure which shows the principal part schematic structure of a polymer dispersion | distribution liquid crystal part. The figure explaining the 1st state of a polymer dispersion | distribution liquid crystal part. The figure explaining the 2nd state of a polymer dispersion | distribution liquid crystal part. The figure which shows the pattern which applies a voltage lower than the maximum voltage in a 2nd state. The figure which shows the pattern which changes a voltage to a sine wave shape. The figure which shows the other pattern which applies a voltage lower than the maximum voltage in a 2nd state. The figure which shows the pattern which applies a time voltage shorter than response time in a 2nd state. FIG. 6 is a diagram illustrating a lighting device according to a modification example of Example 1. The figure explaining the 2nd state of a polymer dispersion | distribution liquid crystal part. FIG. 5 is a diagram illustrating a schematic configuration of a projector according to a second embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illuminating device, 11 Laser light source, 12 Diffractive optical element, 13 Polymer dispersion | distribution liquid crystal part, I Illumination object, 21 Incident side transparent substrate, 22 Outgoing side transparent substrate, 23 particle | grains, 24 Liquid crystal molecule, 25 Polymer member layer, 26 1st Electrode, 27 second electrode, 28 power supply unit,
33 polymer dispersed liquid crystal part, 34 liquid crystal molecules, 35 polymer member, 100 projector, 10R R light illumination device, 10G G light illumination device, 10B B light illumination device, 11
Laser light source for RR light, laser light source for 11G G light, laser light source for 11B B light, 12R
Diffractive optical element for R light, diffractive optical element for 12G G light, diffractive optical element for 12B B light, 1
Polymer dispersion liquid crystal part for 3R R light, polymer dispersion liquid crystal part for 13G G light, polymer dispersion liquid crystal part for 13B B light, spatial light modulation device for 61R R light, spatial light modulation device for 61G G light,
61B spatial light modulator for B light, 62 cross dichroic prism, 62a first dichroic film, 62b second dichroic film, 63 projection optical system, 65 screen

Claims (8)

A laser light source for supplying laser light;
A polymer-dispersed liquid crystal part in which liquid crystal molecules are dispersed in a layer having a polymer member,
The polymer-dispersed liquid crystal part is provided at a position where the laser beam is incident,
An illuminating device for illuminating an illumination target by superimposing the laser light from the polymer-dispersed liquid crystal portion every time the orientation of the liquid crystal molecules is changed. The polymer-dispersed liquid crystal portion repeatedly changes between a first state in which the laser light from the polymer-dispersed liquid crystal portion is scattered and a second state in which the scattering of the laser light is reduced from the first state. The lighting device according to claim 1. The polymer-dispersed liquid crystal part is repeatedly changed between the first state and the second state by repeatedly applying a voltage to the polymer-dispersed liquid crystal part and stopping the application of the voltage. The lighting device according to claim 2. The polymer dispersed liquid crystal part is
When the orientation of the liquid crystal molecules is aligned by applying a voltage to the polymer-dispersed liquid crystal portion, the application of voltage is stopped in the first state, and the orientation of the liquid crystal molecules is substantially uniform in the second state. A voltage lower than the maximum voltage is applied,
When alignment of liquid crystal molecules is made uniform by stopping application of voltage to the polymer-dispersed liquid crystal portion, voltage is applied in the first state, and in the second state, the first
The lighting device according to claim 2, wherein a voltage lower than an applied voltage in the state is applied. 3. The polymer-dispersed liquid crystal unit starts to change to the first state before the time until the alignment of the liquid crystal molecules is maintained in the second state. Or the illuminating device of 3. The lighting device according to claim 1, wherein a haze value of the polymer-dispersed liquid crystal portion in the first state is 5% to 20%. Having a diffractive optical element that shapes an irradiation region of the laser light by diffracting the laser light;
The illumination device according to claim 1, wherein the polymer-dispersed liquid crystal unit is provided in an optical path between the diffractive optical element and the illumination target. A projector comprising the illumination device according to claim 1.

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