JP4784262B2 - Illumination device and image display device - Google Patents

Description

  The present invention relates to a lighting device and an image display device.

In recent years, ultra-high pressure mercury lamps are often used as light sources in image display devices. However, lamp life, impossibility of instant lighting, narrow color reproducibility range, and light resistance of liquid crystal light valves due to ultraviolet wavelength irradiation. Due to these problems, an image display device using a solid light source has been proposed (for example, Patent Document 1).
The laser display device described in Patent Document 1 includes red, green, and blue semiconductor lasers, a plurality of collimator lenses that collimate laser light emitted from the semiconductor lasers, and light that is collimated by the collimator lenses. And a spatial light modulator that modulates the light emitted from each microlens. The light that has passed through each spatial light modulator is combined by a dichroic mirror and displayed on a screen by a projector lens. In this laser display device, the microlens can be rotated with the optical axis as a rotation axis, and by rotating the microlens, speckle noise of the laser light that irradiates the spatial light modulator is reduced or eliminated. It has become.
Japanese Patent Laid-Open No. 11-64789

  However, in the laser display device described in Patent Document 1, since the microlens is rotated in order to reduce speckles, mechanical parts such as a rotational drive system are required, and the cost is increased. Further, noise associated with the rotation of the rotation drive system is generated, or the rotation drive system deteriorates due to long-term use, resulting in a decrease in reliability.

  The present invention has been made to solve the above-described problem, and has a simple configuration that can suppress the occurrence of glare of emitted light and improve the reliability. An object is to provide an apparatus.

In order to achieve the above object, the present invention provides the following means.
The illumination device of the present invention includes a laser light source that emits monochromatic light, and a polarization rotation element that temporally changes a polarization plane of light emitted from the laser light source by changing an applied voltage or an applied magnetic field with time. And an optical path separating element for separating the optical path of the emitted light emitted from the polarization rotating element, and a light guide means for causing each light separated by the optical path separating element to enter the projection member, and the polarization rotating The element is divided into predetermined areas, and a polarization plane of light transmitted through the polarization rotating element is controlled for each of the areas .
In the illumination device of the present invention, the polarization rotator is composed of a liquid crystal element in which an individual electrode is provided for each region, and a predetermined voltage is applied to the electrode provided for each region at a different frequency. It is good also as a structure to be performed.

  In the illumination device according to the present invention, the light emitted from the light source enters the polarization rotation element. Then, the polarization plane of the light emitted from the polarization rotation element is temporally changed. The light emitted from the polarization rotation element is incident on the optical path separation element, and then the optical path is separated. Each light separated from the optical path is incident on the light guide and then irradiated on the projection target member. Thus, since the polarization plane of the light emitted from the polarization rotation element changes with time, the glare pattern changes with time. Time coherence will reduce coherence. As a result, the light projected on the projection member is light with reduced glare (scintillation, speckle). Therefore, with a simple structure, the occurrence of glare in the emitted light is suppressed, and since a rotational drive system is not used as in the prior art, the present invention does not deteriorate even when used for a long time, improving reliability. It becomes possible to make it.

  Further, in the illumination device of the present invention, the optical path separation element transmits polarized light having a specific vibration direction out of the light emitted from the polarization rotation element, and the vibration direction is different from the specific vibration direction. A polarization separation element having a polarization separation surface that reflects the polarized light is preferable.

  In the illumination device according to the present invention, the light emitted from the polarization rotation element enters the polarization separation element, and is separated into polarized light having a specific vibration direction and polarized light having another vibration direction. Each separated light is incident on the light guide and then irradiated onto the projection member. Therefore, the optical path of the light emitted from the polarization rotation element can be separated with a simple configuration.

  In the illumination device of the present invention, it is preferable that a phase plate is provided on an optical path of the polarized light having the specific vibration direction or the polarized light having the other vibration direction.

  In the illumination device according to the present invention, for example, by using a λ / 2 plate as a phase plate, the polarization direction of each light emitted from the polarization separation element is aligned with polarized light in another vibration direction or a specific vibration direction. be able to. Therefore, for example, when a liquid crystal display device is used as the projection member, a member such as a polarization rotation element that aligns the polarization direction of the incident light is not required upstream of the liquid crystal display device, so that the light utilization efficiency is improved. It becomes possible.

In the illumination device of the present invention, the polarization rotation element is divided into predetermined regions,
It is preferable that a polarization plane of light transmitted through the polarization rotation element is controlled for each region.

  In the illuminating device according to the present invention, the polarization plane of the light transmitted through the polarization rotation element can be made different for each predetermined region. Thereby, since the light emitted from each region is temporally integrated while being irradiated onto the projection target member, the generation of speckle can be further reduced. In addition, for example, when a plurality of light sources are used, the polarization plane can be rotated for each light source by arranging the light source for each predetermined region of the polarization rotation element, so that the generation of speckle can be efficiently suppressed. It becomes possible.

  In the illuminating device of the present invention, it is preferable that the light guide unit is a lens array that uniformizes an illuminance distribution of each light separated from the optical path separation element.

  In the illumination device according to the present invention, each light emitted from the optical path separation element enters the lens array. Thereby, the light emitted from the lens array can be irradiated to the projection member after the illuminance distribution is made uniform and the time integration is performed to suppress the generation of speckle.

  In the illuminating device of the present invention, it is preferable that the light guide unit is a rod integrator that uniformizes an illuminance distribution of each light separated from the optical path separation element.

  In the illumination device according to the present invention, each light emitted from the optical path separation element enters the rod integrator. Each light incident on the rod integrator is mixed by repeating internal reflections, and the light emitted from the rod integrator has a uniform illuminance distribution and time integration to suppress speckle generation. Thereafter, the projection member can be irradiated.

  In the illuminating device of the present invention, it is preferable that the light guide means is a light diffusion member that diffuses each light separated from the optical path separation element.

  In the illumination device according to the present invention, each light emitted from the optical path separation element enters the light diffusing member. Thereby, since each light inject | emitted from a light-diffusion member will reduce coherence, it becomes possible to irradiate a to-be-projected member, after generation | occurrence | production of a speckle is suppressed.

  In the illumination device of the present invention, the light guide means may be a diffractive optical element that converts each light separated from the optical path separation element into a shape and a size of an irradiated surface of the projection target member. preferable.

  In the illumination device according to the present invention, the laser light emitted from the laser light source is converted into the shape and size of the irradiated surface of the light modulation device by the diffractive optical element. Accordingly, it is possible to irradiate the light modulation device with light emitted from the laser light source without waste, so that it is possible to improve the light use efficiency.

Moreover, it is preferable that the illuminating device of this invention is provided with two or more said light sources.
In the illuminating device according to the present invention, since a plurality of light sources are provided, there is an effect that it is possible to increase the luminance of light irradiated to the projection target member.

In the illumination device of the present invention, it is preferable that the plurality of light sources include at least a light source that emits red light, a light source that emits green light, and a light source that emits blue light.
In the illumination device according to the present invention, since the light source includes at least a light source that emits red light, a light source that emits green light, and a light source that emits blue light, a wide range of colors can be expressed, and brightness and color rendering However, it is possible to obtain excellent illumination light.

  An image display device according to the present invention is the illumination device, the projection member, a light modulation device that modulates light emitted from the illumination device according to an image signal, and the light modulation device. And a projection device for projecting light.

  In the image display device according to the present invention, the light emitted from the illumination device enters the light modulation device. Then, the image modulated by the light modulation device is projected by the projection device. At this time, since the light emitted from the lighting device is light with reduced speckles as described above, a good image can be displayed.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[First Embodiment]
Next, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the illumination device 1 according to the present embodiment includes a laser light source (light source) 11 that emits monochromatic light and a liquid crystal element (polarized light) that temporally changes the polarization plane of light emitted from the light source 11. Rotating element) 12, a polarization beam splitter (polarized beam separating element, hereinafter referred to as PBS) 13 as an optical path separating element for separating the optical path of the emitted light emitted from the polarization rotating element 12, and the respective lights separated by the PBS 13. Is provided with a diffractive optical element 14 (light guiding means, hereinafter referred to as DOE (Diffractive Optical Element)).
Examples of the light valve 15 include DMD (Digital Micromirror Device), GLV (Grating Light Valve), and liquid crystal light valve. When a liquid crystal light valve is used, a polarization conversion element is required in the preceding stage in order to align the polarization direction of incident light.

  The PBS 13 transmits polarized light having a specific vibration direction, for example, p-polarized light, and reflects polarized light having another vibration direction different from the specific vibration direction, for example, s-polarized light. It has a polarization separation surface 13b. The first polarization separation surface 13 a is provided on the optical axis O of the laser light source 11 so as to be inclined by 45 degrees. The second polarization separation surface 13b is provided substantially parallel to the first polarization separation surface 13a, and reflects the s-polarized light reflected by the first polarization separation surface 13a to the DOE 14.

  The liquid crystal element 12 is sandwiched between the first electrode 12 a and the second electrode 12 b, the laser light source 11 is disposed on the first electrode 12 a side, and the first and second electrodes 12 a and 12 b are connected to the drive circuit 20. Has been. The drive circuit 20 controls the voltage applied to the liquid crystal element 12 and changes the polarization plane of light emitted from the liquid crystal element 12 over time. Specifically, when the output from the drive circuit 20 is 0 V, the polarization plane of the laser light incident on the liquid crystal element 12 is incident on the first polarization separation surface 13a of the PBS 13 without changing even after emission. That is, since the polarized light of the light incident on the liquid crystal element 12 is p-polarized light in the present embodiment, the polarized light after emission is also p-polarized light.

Further, when the output from the drive circuit 20 is 20 V, the laser light incident on the liquid crystal element 12 is transmitted through the liquid crystal element 12, so that the plane of polarization of the laser light is incident on the liquid crystal element 12. And is incident on the first polarization separation surface 13 a of the PBS 13. At this time, the laser light incident on the first polarization separation surface 13a is converted into a polarization surface that is reflected by the first polarization separation surface 13a, that is, s-polarized light.
The switching frequency between the voltages 0V and 20V output from the drive circuit 20 is set to a frequency higher than the flicker frequency that can be detected by humans.

  The DOE 14 includes a first DOE 14a on which p-polarized light transmitted through the first polarization separation surface 13a is incident, and a second DOE 14b on which s-polarized light reflected on the first polarization separation surface 13a is incident. 2DOEs 14a and 14b are diffraction gratings in which a periodic optical pattern is formed on the same substrate. The first and second DOEs 14a and 14b convert the light separated from the PBS 13 into the shape and size of the irradiated surface of the light valve 15 and make the illuminance distribution uniform. Each light diffracted by the first and second DOEs 14 a and 14 b irradiates the light valve 15.

Next, a method of irradiating the light valve 15 using the illumination device 1 of the present embodiment having the above configuration will be described.
First, when the light source 11 is driven, laser light is emitted from the laser light source 11 and enters the liquid crystal element 12. When the applied voltage in the drive circuit 20 is 0 V, the laser light incident on the liquid crystal element 12 passes through the first polarization separation surface 13a as p-polarized light and enters the first DOE 14a of the DOE 14. Then, after being diffracted by the first DOE 14a, the irradiated surface of the light valve 15 is irradiated.

On the other hand, when the applied voltage in the drive circuit 20 is 20 V, the light incident on the liquid crystal element 12 has its polarization plane rotated from p-polarized light to s-polarized light and reflected by the first polarization separation surface 13a. Reflected at the two-polarized light separation surface 13b. The light reflected by the second polarization separation surface 13b is diffracted by the second DOE 14b of the DOE 14, and then irradiates the irradiated surface of the light valve 15.
Here, the speckle patterns after being diffracted in the first DOE 14a and the second DOE 14b are different as shown in FIG. The light valve 15 overlaps, and the observer sees a signal obtained by integrating speckles from the first DOE 14a and the second DOE 14b, so that the speckle pattern appears to decrease.

In the illuminating device 1 according to the present embodiment, the polarization plane of the light emitted from the liquid crystal element 12 changes with time by changing the voltage to be applied, so the glare pattern changes with time. Therefore, the light emitted from the DOE 14 is time-integrated by the afterimage effect and the coherence is reduced, so that the occurrence of glare (scintillation, speckle) is suppressed. As a result, with a simple configuration, the light projected on the light valve 15 is light with reduced glare. Further, since no rotational drive system is used as in the prior art, reliability can be improved.
The DOE 14 has a configuration in which the first DOE 14a and the second DOE 14b are formed on the same substrate, but the first DOE 14a and the second DOE 14b may be separate.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIG. In each embodiment described below, portions having the same configuration as those of the lighting device 1 according to the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
The illumination device 30 according to the present embodiment is different from the first embodiment in that the drive circuit 31 controls the liquid crystal element 32 for each predetermined region.

As shown in FIG. 3, the liquid crystal element 32 is divided into two regions A and B. The liquid crystal element 32 has a predetermined interval on the incident surface 32a side for each of the regions A and B. The first electrode 36 and the second electrode 37 are provided respectively, and the third surface 38 and the second electrode 36 are opposed to the first and second electrodes 36 and 37 on the emission surface 32b for each of the regions A and B. A fourth electrode 39 is provided.
The first and third electrodes 36 and 38 and the second and fourth electrodes 37 and 39 are connected to the drive circuit 31, respectively. This drive circuit 31 applies a voltage of 0 V and 20 V between the first electrode 36 and the third electrode 38 in a cycle of 20 Hz, and a voltage of 0 V and 20 V between the second electrode 37 and the fourth electrode 39 in a cycle of 50 Hz. It is to be applied at.

  The PBS 41 has first, second, third, and fourth polarization separation surfaces 41a, 41b, 41c, and 41d that transmit p-polarized light and reflect s-polarized light as in the first embodiment. The first to fourth polarization separation surfaces 41 a to 41 d are provided with an inclination of 45 degrees on the optical axis O of the laser light source 11, and the first polarization separation surface 41 a is light transmitted through the region A of the liquid crystal element 32. However, the third polarization separation surface 41c is disposed so that light transmitted through the region B of the liquid crystal element 32 is incident. The second polarization separation surface 41b is arranged so as to reflect the s-polarized light reflected by the first polarization separation surface 41a to the DOE 42, and the fourth polarization separation surface 41d is reflected by the third polarization separation surface 41c. The s-polarized light is arranged so as to be reflected by the DOE 42.

  The DOE 42 is transmitted through the first DOE 42a where the p-polarized light transmitted through the first polarization separation surface 41a is incident, the second DOE 42b where the s-polarized light reflected at the second polarization separation surface 41b is incident, and the third polarization separation surface 41c. A third DOE 42c on which p-polarized light is incident and a fourth DOE 42d on which s-polarized light reflected by the fourth polarization separation surface 41d is incident are provided. Further, the DOE 42 may have a periodic optical pattern formed on the same substrate, and the first to fourth DOEs 42a to 42d may be separate.

Further, a field lens 43 is provided between the DOE 42 and the light valve 15, and the light emitted from the first to fourth DOEs 42 a to 42 d is collimated by the field lens 43 and enters the light valve 15. It has become.
A collimator lens 44 that collimates the laser light emitted from the laser light source 11 is provided between the laser light source 11 and the liquid crystal element 32.

In the illuminating device 30 according to the present embodiment, since the drive circuit 31 controls the areas A and B of the liquid crystal element 32, the polarization plane of the light transmitted through the liquid crystal element 32 can be varied for each predetermined area. . Therefore, the light emitted from the laser light source 11 can select the first to fourth DOEs 42 a to 42 d according to the polarized light after passing through the liquid crystal element 32. That is, since the number of DOEs to be selected is increased as compared with the first embodiment, the number of integrations of the light irradiated to the light valve 15 is increased, so that the speckle pattern can be further suppressed.
In addition, since the light emitted from the first to fourth DOEs 42a to 42d is all mixed by changing the switching cycle of the voltage to be applied for each of the regions A and B, the specification is more than that in the case of switching at the same cycle. Pattern can be reduced.

Note that the switching cycle of the voltage applied between the first electrode 36 and the third electrode 38 and between the second electrode 37 and the third electrode 39 is not limited to the above frequency. Further, the voltage applied between the first electrode 36 and the third electrode 38 and between the second electrode 37 and the third electrode 39 may be different. That is, when 0 V is applied between the first electrode 36 and the third electrode 38, 20 V may be applied between the second electrode 37 and the fourth electrode 39.
Further, although the liquid crystal element 32 is divided into the two regions A and B, it may be divided into three or more.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described with reference to FIG.
The illumination device 50 according to the present embodiment is different from the first embodiment in that a lens array 51 is used as a light guiding unit instead of the DOE 14.
As shown in FIG. 4, the lens array 51 is paired with the first lens array 51a and the first lens array 51a provided at the position where the p-polarized light transmitted through the first polarization separation surface 13a is incident. A second lens array 51b for irradiating the light valve 15 with light emitted from one lens array 51a; a third lens array 51c provided at a position where s-polarized light reflected by the second polarization separation surface 13b is incident; A fourth lens array 51d that is paired with the third lens array 51c and that irradiates the light valve 15 with light emitted from the third lens array 51c is provided. With these first to fourth lens arrays 51a to 51d, the light incident on the light valve 15 is converted into the shape and size of the illuminated surface of the light valve 15, and the illuminance distribution is made uniform. Yes.

  In the illuminating device 50 according to the present embodiment, each light emitted from the lens array 51 is irradiated with the light valve 15 after the illuminance distribution is made uniform and speckle generation is suppressed by time integration. It becomes possible to do.

[Fourth Embodiment]
Next, a fourth embodiment according to the present invention will be described with reference to FIG.
The illumination device 60 according to the present embodiment is different from the first embodiment in that a rod integrator 61 is used as a light guide instead of the DOE 14.
As shown in FIG. 5, the illuminating device 60 condenses the light transmitted through the first polarization separation surface 13a and the light reflected from the second polarization separation surface 13b, and the light collected by the light collection lens 62. A rod integrator 61 that reflects the emitted light inside to make the illuminance distribution uniform, and an irradiation lens 63 that irradiates the light valve 15 with the light emitted from the rod integrator 61 are provided.

  In the illuminating device 60 according to the present embodiment, light having different polarization planes incident on the rod integrator 61 is mixed by repeatedly reflecting inside, and the light emitted from the rod integrator 61 has a uniform illuminance distribution. At the same time, it is possible to irradiate the light valve 15 after time integration and the generation of speckles is suppressed.

[Fifth Embodiment]
Next, a fifth embodiment according to the present invention will be described with reference to FIGS.
The illumination device 70 according to the present embodiment is different from the first embodiment in that a nonlinear optical element 71 is used as an optical path separation element instead of the PBS 14.
As shown in FIGS. 6A and 6B, the nonlinear optical element 71 is embedded in an anisotropic diffraction grating 72 made of an anisotropic medium and a diffraction surface 72 a of the diffraction grating 72 and isotropic medium. And an isotropic diffraction grating 73. Further, the refractive index of the isotropic diffraction grating 73 is n, the refractive index of ordinary light, that is, the refractive index of the anisotropic diffraction grating 72 when light oscillating in the X direction is incident, and the refraction of extraordinary light. If the refractive index of the anisotropic diffraction grating 72 when light that vibrates in the Y direction is incident, ne = ne. The refractive index of the isotropic diffraction grating 73 may be the same as the refractive index no of ordinary light of the anisotropic diffraction grating 72.

  Here, when light oscillating in the Y-axis direction is incident on the nonlinear optical element 71, the anisotropic diffraction grating 72 and the isotropic diffraction grating 73 have the same refractive index as shown in FIG. Light travels straight ahead. On the other hand, when light oscillating in the X-axis direction is incident on the nonlinear optical element 71, the anisotropic diffraction grating 72 and the isotropic diffraction grating 73 have different refractive indexes as shown in FIG. The light is diffracted at the diffraction surface 72a of the isotropic diffraction grating 72 and separated into ± first-order light.

  Further, in place of the DOE 14 of the first embodiment, a lens array 74 is provided as shown in FIG. The lens array 74 includes a first lens 74 a that irradiates the light valve 15 with light that has passed through the nonlinear optical element 71, and diffracted by the diffraction surface 72 a of the anisotropic diffraction grating 72. It consists of a second lens 74b and a second lens 74c for irradiation.

In the illumination device 70 according to the present embodiment, by using the nonlinear optical element 71, the light emitted from the liquid crystal element 12 can be separated with a simple configuration.
In the present embodiment, the anisotropic diffraction grating 72 may be made of a material having birefringence such as a crystal or lithium niobate. Further, although the lens array 74 is used, as in the first embodiment, the light transmitted through the nonlinear optical element 71 and the diffraction surface that is diffracted by the diffraction surface 72a of the anisotropic diffraction grating 72 and diffracts ± first-order light. A diffractive optical element having

[Sixth Embodiment]
Next, a sixth embodiment according to the present invention will be described with reference to FIG.
The illumination device 80 according to the present embodiment is used when the light valve 15 is a liquid crystal light valve in each of the above embodiments. In this case, as shown in FIG. 8, in the illumination device 80, a λ / 2 plate (phase plate) 81 is provided on the optical path of the s-polarized light reflected by the second polarization separation surface 13b. As a result, the s-polarized light reflected by the second polarization separation surface 13b is converted into p-polarized light.

In the illuminating device 80 according to this embodiment, by providing the λ / 2 plate 81, the light emitted from the PBS 13 is aligned with the p-polarized light, so that it is not necessary to use a polarization conversion element in the front stage of the light valve 15. Therefore, it is possible to improve the utilization efficiency of the light emitted from the laser light source 11.
In the present embodiment, the light is aligned with the p-polarized light. However, the λ / 2 plate 81 may be arranged on the optical path of the p-polarized light transmitted through the first polarization separation surface 13a to align with the s-polarized light.

[Seventh Embodiment]
Next, a seventh embodiment according to the present invention will be described with reference to FIG.
The illumination device 90 according to this embodiment is different from the first embodiment in that a plurality of laser light sources 91 (light sources) are provided. The liquid crystal element 92 is divided into three divided areas A, B, and C. An electrode is provided for each of the areas A, B, and C, and these electrodes are controlled by the drive circuit 105. The first, second, and third laser light sources 91a, 91b, and 91c are provided corresponding to the regions A, B, and C, respectively.
As in the first embodiment, the PBS 93 is provided with a polarization separation surface that transmits p-polarized light emitted from the first laser light source 91a and reflects s-polarized light for each of the regions A, B, and C. . Further, the DOE 94 illuminates the light valve 15 with light emitted from each region and separated by the PBS for each of the regions A, B, and C, as in the first embodiment.

In the illumination device 90 according to the present embodiment, the laser light sources 91a, 91b, and 91c are arranged corresponding to the regions A, B, and C of the liquid crystal element 92, so that the polarization planes are changed for the laser light sources 91a, 91b, and 91c. Can be rotated. Therefore, it is possible to efficiently suppress the generation of speckle.
The plurality of light sources is not limited to three, but may be two or four or more. When a plurality of light sources are provided, at least a light source that emits red light, a light source that emits green light, and a light source that emits blue light may be included. For example, the first laser light source 91a may be a red laser, the second laser light source 91b may be a green laser, and the third laser light source 91c may be a blue laser. Further, when a plurality of light sources are provided, they may be arranged in an array.

[Eighth Embodiment]
Next, an eighth embodiment according to the present invention will be described with reference to FIG.
In the present embodiment, a projector (image display device) 100 including the illumination device 90 of the seventh embodiment will be described.
In the laser light source 91, the first, second, and third laser light sources 91a, 91b, and 91c emit red laser light, green laser light, and blue laser light, respectively.
The projector 100 includes a light valve (projection member, light modulation device) 101 such as a DMD that modulates light emitted from the illumination device 90 according to an image signal, and a color image modulated by the light valve 101 on a screen 103. A projection lens (projection device) 102 for projecting onto the projector. The light valve 101 performs time-division driving in synchronization with the laser light source 91.

The projector 100 according to the present embodiment can express a wide range of colors, and can obtain an image with excellent brightness and color rendering. In addition, since the light emitted from the lighting device 90 is light with reduced speckles as described above, a good image can be displayed.
In addition, although the projector using the illumination device 90 has been described in the projector of the present embodiment, any of the illumination devices described above may be used.
When a liquid crystal light valve is used as the light valve 15, the above-described configuration may be used for a single-plate type. However, when a three-plate type is used, a projector 100 is provided by arranging a laser light source for each color around the dichroic prism. Similarly to the above, it is possible to obtain a good image with reduced speckles.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the light guide means may be a light diffusing member that diffuses each light separated by the optical path separation element. The light diffusing member is made of, for example, rubbed glass having fine irregularities on the incident surface.
In addition, although the liquid crystal element 12 was used as the polarization rotation element, PLZT (zircon titanate) which is an oxide ceramic containing lead (Pd), lanthanum (La), zircon (Zr), and titanium (Ti) is used instead. Lanthanum lead acid) may be used. Since this PLZT is an element that can change the polarization plane of transmitted light by applying a voltage in the same manner as the liquid crystal element, the same effect as described above can be obtained.
Further, although the polarization plane is rotated by applying a voltage to the polarization rotation element, a polarization rotation element that produces a Faraday effect in which the polarization plane rotates according to the strength of the magnetic field may be used.

Moreover, as DOE14,42,94, a hologram optical element can also be used, for example. The hologram optical element is, for example, a computer generated hologram (CGH: Computer Generated Hologram) in which interference fringes artificially created by calculation with a computer are formed on a hologram original plate. The computer generated hologram is suitable because it allows easy setting of the divided region of the diffraction grating and does not cause a problem of aberration.
The second polarization separation surfaces 13b and 41b and the fourth polarization separation surface 41d do not have to be polarization separation films, and may be reflection surfaces.

It is a top view which shows the illuminating device which concerns on 1st Embodiment of this invention. It is a figure which shows the speckle pattern by the light guide means of FIG. It is a top view which shows the illuminating device which concerns on 2nd Embodiment of this invention. It is a top view which shows the illuminating device which concerns on 3rd Embodiment of this invention. It is a top view which shows the illuminating device which concerns on 4th Embodiment of this invention. It is explanatory drawing which shows the optical path separation element used for the illuminating device which concerns on 4th Embodiment of this invention. It is a top view which shows the illuminating device which concerns on 5th Embodiment of this invention. It is a top view which shows the illuminating device which concerns on 6th Embodiment of this invention. It is a top view which shows the illuminating device which concerns on 7th Embodiment of this invention. It is a top view which shows the image display apparatus which concerns on 8th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,30,50,60,70,80,90 ... Illuminating device, 11, 91 ... Laser light source (light source), 12, 92 ... Liquid crystal element (polarization rotation element), 13, 41, 93 ... PBS (polarization separation element) , 14, 42, 94... DOE (light guiding means), 15... Light valve (projected member), 51. Lens array (light guiding means), 61. Rod integrator (light guiding means), 71. Element (optical path separation element), 81 ... λ / 2 plate (phase plate), 101 ... Light valve (light modulation device), 102 ... Projection lens (projection device)

Claims (11)

A laser light source that emits monochromatic light;
A polarization rotator that temporally changes the polarization plane of the light emitted from the laser light source by changing the applied voltage or applied magnetic field over time ;
An optical path separating element for separating the optical path of the emitted light emitted from the polarization rotating element;
A light guide means for causing each light separated by the optical path separation element to enter the projection member ,
The illumination apparatus, wherein the polarization rotation element is divided into predetermined areas, and a polarization plane of light transmitted through the polarization rotation element is controlled for each area .   The optical path separation element transmits a polarized light having a specific vibration direction out of the emitted light emitted from the polarization rotation element, and reflects a polarized light having a vibration direction different from the specific vibration direction. The illuminating device according to claim 1, wherein the illuminating device has a polarization separating element.   The lighting device according to claim 2, wherein a phase plate is provided on an optical path of the polarized light having the specific vibration direction or the polarized light having the other vibration direction. The polarization rotation element is composed of a liquid crystal element provided with an individual electrode for each region,
The lighting device according to any one of claims 1 to 3, wherein a predetermined voltage is applied at a different frequency to the electrodes provided in each region .   5. The illumination device according to claim 1, wherein the light guide unit is a lens array that uniformizes an illuminance distribution of each light separated by the optical path separation element. 6. .   5. The illumination device according to claim 1, wherein the light guide unit is a rod integrator that uniformizes an illuminance distribution of each light separated by the optical path separation element. 6. .   The lighting device according to any one of claims 1 to 4, wherein the light guide means is a light diffusion member that diffuses each light separated from the optical path separation element.   2. The diffractive optical element, wherein the light guide means is a diffractive optical element that converts each light separated from the optical path separating element into a shape and a size of an irradiated surface of the projection member. 5. The lighting device according to any one of 4. The lighting apparatus according to claim 1, wherein a plurality of the laser light sources are provided. Wherein the plurality of laser light sources, the lighting device according to claim 9, characterized in that it comprises a laser light source for emitting at least red light laser source for emitting a laser light source that emits green light, blue light. The lighting device according to any one of claims 1 to 10,
A light modulation device that is the projection member and modulates light emitted from the illumination device according to an image signal;
An image display device comprising: a projection device that projects light modulated by the light modulation device.

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