JP2006330350A - Projector and optical modulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector restraining occurrence of glaring (scintillation) and hardly causing the lowering of luminance or resolution. <P>SOLUTION: The projector 801 is equipped with an optical modulation means 823, and a light source 810 radiating the optical modulation means 823 with light, and is constituted by disposing a phase distribution changing means 833 capable of changing the spatial phase distribution of the light according to an electric signal between the optical modulation means 823 and the light source 810. By inputting the electric signal which varies temporally in the phase distribution changing means 833, the phase distribution of the light radiated from the light source 810 to the optical modulation means 823 is changed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector and an optical modulator.

Conventionally, in rear projection televisions using light modulation means, the occurrence of glare (scintillation) has been reduced by increasing the diffusibility of the screen (see, for example, Patent Document 1).
JP 2003-4914 A

  However, the method as described in Patent Document 1 has problems such as darkening and resolution reduction. Moreover, even if measures such as Patent Document 1 are taken, the glare reduction is not sufficient.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a projector that suppresses the occurrence of glare (scintillation) and causes little reduction in luminance and resolution. Another object of the present invention is to provide an optical modulator that can suppress the occurrence of glare (scintillation) when used in a projector.

  In order to solve the above-described problems, a projector according to the present invention is a projector including a light modulation unit and a light source that irradiates light to the light modulation unit, and the projector is provided between the light modulation unit and the light source. Phase distribution changing means capable of changing the phase distribution of spatial light by an electrical signal is arranged, and an electric signal that varies with time is input to the phase distribution changing means, so that the light source The phase distribution of the light irradiated to the light modulation means changes.

  According to such a projector, since a glare (scintillation) pattern changes with time in the projected image, it is difficult to feel the glare due to the time integration due to the afterimage effect. It is possible to improve the brightness of the projected light as compared with a countermeasure using a simple screen. In addition, the resolution is less degraded than in the prior art. Furthermore, since a large movable part such as a motor or an electromagnetic actuator is not required, noise is low and reliability is high. Note that the electrical signal can be input such that the voltage value or the current value varies with time, for example.

  In the projector according to the aspect of the invention, the frequency of the electrical signal may be higher than the frequency of flicker that can be detected by humans. As a result, it is possible to reliably eliminate the problem of flicker being detected in the projected image.

  In the projector according to the aspect of the invention, the light modulation unit includes a red light modulation unit, a green light modulation unit, and a blue light modulation unit, and the phase distribution changing unit includes at least the green light modulation unit. It can be arranged between the light source. Since green has the highest visibility for humans, it is preferable to provide at least phase distribution changing means for the color.

  In the projector according to the present invention, the phase distribution changing unit may be disposed closer to the light modulating unit than the light source. The phase distribution change means needs to change the phase at a position conjugate with the light modulation means. For this purpose, it is preferable to dispose the phase distribution change means closer to the light modulation means than the light source.

  In the projector according to the aspect of the invention, an imaging optical system may be provided between the phase distribution changing unit and the light modulating unit. By providing such an imaging optical system, the phase distribution changing means and the light modulating means can be in a conjugate positional relationship.

  In the projector of the present invention, a liquid crystal panel can be adopted as the phase distribution changing unit. According to the liquid crystal panel, the spatial phase distribution of light can be suitably changed by an electric signal.

  Here, as the liquid crystal panel, a liquid crystal panel in which liquid crystal is sealed in two non-parallel substrates can be employed. In this case, the cell gap of the liquid crystal panel becomes non-uniform in the substrate plane, and the spatial phase distribution of light does not change at a time, but becomes a phase distribution that varies from time to time. As a result, since the glare pattern changes with time in the projected image, the glare pattern is hardly integrated due to time integration due to the afterimage effect.

  Further, the liquid crystal panel may be formed by enclosing liquid crystal between a pair of substrates, and having at least one of the substrates provided with irregularities on the surface facing the liquid crystal. In this case as well, the cell gap of the liquid crystal panel becomes non-uniform in the substrate plane, and the spatial phase distribution of light does not change at once, but becomes a phase distribution that varies from time to time. As a result, since the glare pattern changes with time in the projected image, the glare pattern is hardly integrated due to time integration due to the afterimage effect. In addition to the liquid crystal panel, for example, a deformable mirror can be used as the phase distribution changing unit.

  In the projector according to the present invention, the light modulation unit and the phase distribution changing unit can be integrally formed. In this case, the configuration is simple and the manufacturing process is also simple. Further, when the light modulation means and the phase distribution changing means are each composed of a liquid crystal panel in which a liquid crystal layer is sandwiched between a pair of substrates, one of the substrates constituting the liquid crystal panel is shared and integrated. be able to. In other words, the liquid crystal layer is sandwiched between the second substrate and the third substrate with respect to the light modulation means including the liquid crystal panel having the configuration in which the liquid crystal layer is sandwiched between the first substrate and the second substrate. The phase distribution changing means can be constituted by the liquid crystal panel.

  Next, in order to solve the above-described problem, the optical modulator of the present invention includes an optical modulation main body and a phase distribution changing unit capable of changing a spatial light phase distribution by an electrical signal. The optical modulation main body and the phase distribution changing unit are integrally formed, and an electric signal that changes with time is input to the phase distribution changing unit, thereby transmitting the phase distribution changing unit. Then, the phase distribution of the light introduced into the light modulator changes. According to such an optical modulator, it is possible to effectively prevent the occurrence of light glare after the modulation, and to reduce the size of the optical modulator by integrating the optical modulation main body and the phase distribution changing unit. In addition, the configuration can be simplified. Specifically, with respect to the light modulation main body composed of a liquid crystal panel having a configuration in which a liquid crystal layer is sandwiched between the first substrate and the second substrate, between the second substrate and the third substrate. A phase distribution changing unit can be configured and integrated by a liquid crystal panel sandwiched between liquid crystal layers.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, in order to make each layer and each member the size which can be recognized on drawing, the scale is varied for every layer and each member.

[First Embodiment]
FIG. 1 is an explanatory diagram conceptually showing the structure of a projector according to a first embodiment to which the present invention is applied. A projector 801 shown in FIG. 1 is a three-plate projector, in which a reference numeral 810 is a light source device, 813 and 814 are dichroic mirrors, 815, 816 and 817 are reflection mirrors, and 832, 833 and 834 are phase distribution changes. 822, 823, and 824 are light modulation means, 825 is a dichroic prism, and 826 is a projection optical system.
The three-plate projector modulates light source light by three light modulation means corresponding to the three primary colors.

  The light source device 810 is disposed on the optical axis of the three-plate projector 801, and is composed of, for example, a full-color LED light source in addition to an ultrahigh pressure mercury lamp. Light emitted from the light source device 810 enters the dichroic mirror 813.

  The dichroic mirror 813 transmits red light from the light source device 810 and reflects blue light from the light source device 810 and green light from the light source device 810. Then, the red light transmitted through the dichroic mirror 813 is reflected by the reflection mirror 817 and enters the red phase distribution changing unit 832.

  The dichroic mirror 814 transmits blue light and reflects green light. Then, the green light reflected by the dichroic mirror 814 enters the green phase distribution changing unit 833. Further, the blue light transmitted through the dichroic mirror 814 is reflected by the reflection mirrors 815 and 816 and enters the blue phase distribution changing unit 834.

  In each of the color phase distribution changing means 832, 833, and 834, the spatial light phase distribution can be changed by an electric signal. In this embodiment, a liquid crystal layer is sandwiched between a pair of substrates as the phase distribution changing means. LCD panels are used. That is, by inputting an electric signal that varies with time to the liquid crystal panel, it is possible to change the phase distribution of light irradiated from the light source device 810 to the light modulation means 822, 823, and 824 over time. Has been.

  The light transmitted through the color phase distribution changing units 832, 833, and 834 is incident on the color light modulating units 822, 823, and 824. The light modulation means 822, 823, and 824 employ liquid crystal light valves, and can modulate each color light.

  The three color lights modulated by the respective color light modulation means 822, 823, and 824 are incident on the cross dichroic prism 525. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected on the projection screen 827 by the projection lens 826 which is a projection optical system, and an enlarged image is displayed.

  In the three-plate projector 801 configured as described above, since the phase distribution changing means 832, 833, and 834 are disposed between the color light modulation means 822, 823, and 824 and the light source device 810, each color light modulation means 822 is provided. The phase distribution of the light incident on 823 and 824 for each time changes. As a result, in the projected image, the glare (scintillation) pattern changes with time, so that the glare is difficult to be sensed by time integration due to the afterimage effect. Furthermore, for example, it is possible to improve the brightness of the projected light as compared with a method of eliminating the glare by increasing the diffusibility of the screen, and the resolution is reduced less than when using such a screen. Moreover, according to this embodiment, since a large movable part such as a motor or an electromagnetic actuator is not necessary, noise is low and reliability is high.

  Here, the configuration of each of the color phase distribution changing units 832, 833, and 834 will be described with reference to FIG. Since the color phase distribution changing units 832, 833, and 834 have the same configuration, the colors are collectively referred to as the phase distribution changing unit 830 in FIG.

  The phase distribution changing unit 830 includes a liquid crystal panel, and changes the spatial light phase distribution by transmitting an electric signal to the liquid crystal panel. The phase distribution changing means 830 shown in FIG. 2 has a configuration in which a liquid crystal (liquid crystal layer) 39 is sealed between two non-parallel substrates 31 and 32. As shown in FIG. 4, the rubbing direction of the alignment film (not shown) disposed on each of the substrates 31 and 32 is substantially parallel, and the incident polarization direction is the rubbing direction.

  In such a phase distribution changing means 830, when a voltage (electrical signal) that changes with time as shown in FIGS. 3A to 3D is applied by the power source 33, FIGS. 4A and 4B are applied. As shown in (1), it is possible to change only the optical length (product of refractive index and distance) without changing the polarization direction of light. By making the pair of substrates 31 and 32 non-parallel to each other, the cell gap becomes non-uniform, and the spatial phase distribution of light does not change at a time, but becomes a phase distribution that varies from time to time. As a result, the glare pattern changes with time and is integrated over time due to the afterimage effect, making it difficult to feel the glare.

  In the present embodiment, the frequency of the electrical signal input to the phase distribution changing unit 830 is assumed to be higher than the flicker frequency that can be detected by humans. This reliably eliminates the problem that flicker is detected in the projected image. Further, the phase distribution changing means 830 (832, 833, 834) is disposed closer to the light modulation means 822, 823, 824 than the light source device 810 as shown in FIG. As a result, the phase can be changed at a position conjugate with the light modulation means 822, 823, and 824. In this embodiment, the phase distribution changing means 832, 833, and 834 are arranged for the light modulating means 822, 823, and 824 of each color, but for example, the phase is changed only for the green light modulating means 823. Distribution changing means 833 may be provided. Since green has the highest visibility for humans, it may be sufficient to provide at least the phase distribution changing means 833 for the color. In this case, the configuration is simple and the cost can be reduced.

  Further, as the phase distribution changing means 830, for example, as shown in FIGS. 5A to 5C, at least one of the pair of substrates 31 and 32 enclosing the liquid crystal 39, the surface facing the liquid crystal 39. It is also possible to adopt a material in which irregularities are formed. FIG. 5A shows the surface of the substrate 31 facing the liquid crystal 39 (the sandwiching surface of the liquid crystal 39) with a recess 31a, and FIG. 5B shows the surface of the substrate 31 facing the liquid crystal 39 (the liquid crystal 39). 5 (c), a convex portion 31c is formed on the surface of the substrate 31 facing the liquid crystal 39 (the sandwiching surface of the liquid crystal 39).

  Even in the phase distribution changing means 830 having irregularities on the sandwiching surface of the liquid crystal 39, the cell gap becomes non-uniform in the substrate plane, and the spatial phase distribution of light does not change at once, Different phase distributions can be used.

[Second Embodiment]
Subsequently, a modification of the projector according to the present invention will be described. FIG. 6 is an explanatory diagram conceptually showing the structure of a projector 802 according to the second embodiment to which the present invention is applied. The projector 802 is a three-plate projector. In the figure, reference numeral 810 is a light source device, 813 and 814 are dichroic mirrors, 815, 816 and 817 are reflection mirrors, 832, 833 and 834 are phase distribution changing means, 842, 843 and 844 are imaging optical systems, 822, 823 and 824 are light modulation means, 825 is a dichroic prism, and 826 is a projection optical system.

  1 is different from the projector 801 shown in FIG. 1 in that an imaging optical system 842, 843, 844 is disposed between the light modulating means 822, 823, 824 and the phase distribution changing means 832, 833, 834. Is a point. The imaging optical systems 842, 843, and 844 are composed of lenses, and adjust the modulation means 822, 823, and 824 and the phase distribution change means 832, 833, and 834 in a conjugate positional relationship. Even in this case, the imaging optical system 843 may be disposed only between the green light modulating unit 823 and the phase distribution changing unit 833.

  Also in such a projector 802, phase distribution changing means 832, 833, and 834 are disposed between the color light modulating means 822, 823, and 824 and the light source device 810, and light is emitted by the imaging optical systems 842, 843, 844. Since the modulating means 822, 823, 824 and the phase distribution changing means 832, 833, 834 are arranged in a conjugate positional relationship, the phase of light incident on each color light modulating means 822, 823, 824 for each time. The distribution will change. As a result, in the projected image, the glare (scintillation) pattern changes with time, so that the glare is difficult to be sensed by time integration due to the afterimage effect. Furthermore, for example, it is possible to improve the brightness of the projected light as compared with a method of eliminating the glare by increasing the diffusibility of the screen, and the resolution is reduced less than when using such a screen. Moreover, according to this embodiment, since a large movable part such as a motor or an electromagnetic actuator is not necessary, noise is low and reliability is high.

  For example, like the projector 804 shown in FIG. 9, one phase distribution changing unit 830 is used, and the phase distribution changing unit 830 and the light modulating units 822, 823, and 824 of the respective colors are connected to the imaging optical systems 861 and 862. It can also be arranged at a conjugate position. In this case, since the phase can be changed for each color by one phase distribution changing unit 830, the configuration becomes simple and the cost can be reduced.

[Third Embodiment]
Next, FIG. 7 is an explanatory diagram conceptually showing the structure of a projector 803 according to a third embodiment to which the present invention is applied. The projector 803 includes a light source device 810, a deformable mirror 851, an imaging optical system 852, a light modulation unit 853, a projection optical system 826, and a projection screen 827. The light source device 810, the projection optical system 826, and the projection screen 827 are the same as the projector 801 of the first embodiment shown in FIG.

  The deformable mirror 851 is a reflection type light modulation device as shown in FIG. 8, for example, and the spatial phase distribution of light can be changed by an electric signal. Specifically, it is configured using a mirror device 52 that can be deformed by an applied voltage, and is deformed as shown in FIGS. 8 (a) to 8 (b). By inputting an electric signal that varies with time to such a deformable mirror 851, the light from the light source device 810 is reflected to the light modulation means 853 while changing the phase distribution for each time. It is possible.

  The light reflected by the deformable mirror 851 enters the light modulation means 853 that is in a conjugate positional relationship with the deformable mirror 851 by the imaging optical system (lens) 852. The light modulation means 853 is a light modulation means, and employs a digital mirror device or LCOS, for example.

  Also in such a projector 803, a deformable mirror 851 as a phase distribution changing unit is disposed between the light modulating unit 853 and the light source device 810, and the light modulating unit 853 and the deformable mirror 851 are formed by the imaging optical system 852. Are arranged in a conjugate positional relationship, so that the phase distribution of the light incident on the light modulation means 853 for each time changes. As a result, in the projected image, the glare (scintillation) pattern changes with time, so that the glare is difficult to be sensed by time integration due to the afterimage effect.

[Fourth Embodiment]
Next, FIG. 12 is an explanatory diagram conceptually showing the structure of the projector 100 according to the fourth embodiment to which the present invention is applied. The projector 100 is a so-called rear projector that projects light on one surface of the screen 106 and observes an image by observing light emitted from the other surface of the screen 106. The projector 100 accommodates the projection unit 10 in a housing 102, and the projection unit 10 includes various functional units (dichroic mirrors 813 and 814, reflections) from the light source 810 to the projection optical system 826 shown in FIG. Mirrors 815 to 817, phase distribution changing means 832 to 834, light modulation means 822 to 824, dichroic prism 825, and the like).

  In the projector 100, light projected from the projection unit 10 through the projection lens 10 toward the reflection unit 104 is reflected by the reflection unit 104 toward the screen 106. The screen 106 is a transmissive screen that is provided on a predetermined surface of the housing 102 and transmits light from the projection unit 10 that is modulated in accordance with an image signal. The light from the reflection unit 104 enters from the surface of the screen 106 on the inside of the housing 102 and then exits from the surface of the viewer. The viewer will appreciate the image by the light emitted from the screen 106.

  Also in such a projector 100, the light modulator (822-824) and the light source device (810) similar to those shown in FIG. 1 are provided in the projection unit 10, and the light modulator and the light source device are provided. Between these, phase distribution changing means (832 to 834) are arranged. As a result, in the projected image, the glare (scintillation) pattern changes with time, so that the glare is difficult to be sensed by time integration due to the afterimage effect.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. The accompanying projector is also included in the technical scope of the present invention. For example, in the first embodiment, the phase distribution changing means 832, 833, and 834 are disposed in the vicinity of the light modulation means 822, 823, and 824, but as shown in FIGS. 10 and 11 The light modulation means (light modulation section) 820 and the phase distribution change means (phase distribution change section) 830 can be configured integrally.

  FIG. 10 shows an optical modulator in which the light modulation means 820 is integrated with the phase distribution change means 830 having the configuration shown in FIG. It is a substrate. Further, FIG. 11 shows an optical modulator in which the optical modulation means 820 is integrated with the phase distribution changing means 830 having the unevenness shown in FIG. With such a configuration, the configuration of the projector is further simplified, and alignment and the like are not required and manufacturing efficiency is improved as compared with the case where a light modulating unit and a phase distribution changing unit are separately provided.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows notionally 1st Embodiment of the projector of this invention. Sectional drawing which shows an example of a phase distribution change means typically. Explanatory drawing which shows some examples of the electrical signal input into a phase distribution change means. Explanatory drawing which shows the effect | action of a phase distribution change means. Sectional drawing which shows the some modification of a phase distribution change means typically. Explanatory drawing which shows notionally 2nd Embodiment of the projector of this invention. Explanatory drawing which shows notionally 3rd Embodiment of the projector of this invention. Sectional drawing which shows typically an example of the phase distribution change means used for the projector of FIG. Explanatory drawing which shows notionally the modification of the projector of FIG. Sectional drawing which shows typically about an example of the device which integrated the phase distribution change means and the light modulation means. Sectional drawing which shows typically about an example of the device which integrated the phase distribution change means and the light modulation means. Explanatory drawing which shows notionally 4th Embodiment of the projector of this invention.

Explanation of symbols

  801 ... Projector, 810 ... Light source device (light source), 822, 823, 824 ... Light modulation means, 832,833,834 ... Phase distribution changing means

Claims (10)

A projector comprising: a light modulation means; and a light source that irradiates light to the light modulation means,
Between the light modulation means and the light source, a phase distribution changing means capable of changing a spatial light phase distribution by an electrical signal is arranged,
A projector, wherein a phase distribution of light emitted from the light source to the light modulating unit is changed by inputting an electric signal that varies with time to the phase distribution changing unit.   The projector according to claim 1, wherein the phase distribution changing unit includes a liquid crystal panel having a configuration in which a liquid crystal layer is sandwiched between two non-parallel substrates.   The phase distribution changing means comprises a liquid crystal panel having a configuration in which a liquid crystal layer is sandwiched between a pair of substrates, and at least one of the substrates has irregularities formed on a surface facing the liquid crystal layer. The projector according to claim 1 or 2.   The projector according to claim 1, wherein the phase distribution changing unit is a deformable mirror.   5. The projector according to claim 1, wherein a frequency of an electric signal input to the phase distribution changing unit is higher than a flicker frequency that can be sensed by a human. 6.   The light modulation means includes a red light modulation means, a green light modulation means, and a blue light modulation means, and the phase distribution changing means is a spatial light source light incident on at least the green light modulation means. 6. The projector according to any one of 1 to 5, characterized in that the phase distribution is changed.   The projector according to any one of claims 1 to 6, wherein the phase distribution changing unit is disposed closer to the light modulation unit than the light source.   8. The projector according to claim 1, wherein an imaging optical system is disposed between the phase distribution changing unit and the light modulating unit. A light modulation main body and a phase distribution changer capable of changing a spatial light phase distribution by an electrical signal;
The optical modulation main body and the phase distribution changing unit are integrally formed, and an electric signal that changes with time is input to the phase distribution changing unit, thereby transmitting the phase distribution changing unit. Then, the optical modulator is characterized in that the phase distribution of light introduced into the optical modulator changes.   The light modulation unit includes a liquid crystal panel having a configuration in which a liquid crystal layer is sandwiched between a first substrate and a second substrate, and the phase distribution changing unit is disposed between the second substrate and the third substrate. The optical modulator according to claim 9, comprising a liquid crystal panel having a configuration in which a liquid crystal layer is sandwiched.

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