JP2006163224A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light quantity controlled projector which can easily control the quantity of illuminating light of a liquid crystal panel or the like without requiring a complicated mechanism for light quantity control nor heating a polarizer provided on an incidence face of the liquid crystal panel. <P>SOLUTION: In a projector 10, the angle of rotation of a reflective polarizer 31c constituting an illuminating light generation unit 30 is changed on the basis of a classification of a video signal and a luminance range to control gradations of liquid crystal panels 51b, 51g, and 51r while controlling the intensity of illuminating light emitted from a light source device, so that brightness adapted to a classification of an image to be projected and an environment for use can be set and the power of expression of the image can be enhanced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projector that projects an image using a light modulation device such as a liquid crystal panel.

  As a conventional projector, three liquid crystal panels are illuminated with illumination light of each color, image light of each color emitted from the illuminated three liquid crystal panels is synthesized, and the synthesized color image is appropriately enlarged by a projection lens. There is something to project with.

  Among the projectors described above, there is a projector in which a diaphragm mechanism “dynamic iris” that opens and closes according to the brightness of each scene is provided in the illumination device portion (see Non-Patent Document 1). In this diaphragm mechanism, a light-shielding plate is inserted between two fly-eye lenses constituting the illuminating device portion, and the light quantity can be adjusted by rotating the light-shielding plate.

  In addition, there is another projector in which an aperture having a structure in which a plurality of elongated openings are arranged vertically in the longitudinal direction is movably disposed in the vicinity of the fly-eye lens in the illumination system (see Patent Document 1). In this projector, the dimming element driver for driving the diaphragm is controlled based on the brightness signal obtained from the video signal, and the illumination light quantity is adjusted by moving the diaphragm by the dimming element driver.

  In addition, the illumination system is provided with a diaphragm having a variable aperture area and a diaphragm drive device that changes the aperture area of the diaphragm so that the luminance signal level for diaphragm control detected by the luminance signal level detector is substantially constant. There is also a projector that variably controls the aperture area of the illumination system (see Patent Document 2).

  In addition, there is a projector in which an illumination system is provided with a dimming polarizing plate that is arranged to be rotatable around an optical axis in front of a liquid crystal panel (see Patent Document 3). In this projector, the light intensity for illuminating the liquid crystal panel can be adjusted by tilting the polarization axis of the light control polarizing plate with respect to the polarization axis of the polarizing plate provided on the incident surface of the liquid crystal panel. Yes.

  In addition, there is a projector in which an illumination system is provided with a wave plate arranged so as to be rotatable around an optical axis with respect to a liquid crystal panel (see Patent Document 4). In this projector, the light intensity for illuminating the liquid crystal panel can be adjusted by tilting the optical axis of the wave plate with respect to the polarization axis of the polarizing plate provided on the incident surface of the liquid crystal panel.

In addition, there is also a light intensity adjusting device in which a pair of polarizing plates is provided on the light emission side of the light source, and one of the polarizing plates is rotatable about the optical axis (see Patent Document 5). In this light intensity adjusting device, the light intensity can be automatically finely adjusted without changing the supply voltage to the light source.
http://www.phileweb.com/news/d-av/200409/02/11043.html, Digital AV NEWS new product news release (2004/09/02), "Panasonic," Hollywood picture quality "further evolved Released new liquid professional model "TH-AE700" JP 2003-186111 A JP 2003-29203 A JP-A-5-29203 JP 2004-258063 A Japanese Patent Laid-Open No. 5-48839

  However, in the method of adjusting the amount of light by the diaphragm as described in Non-Patent Document 1 and Patent Documents 1 and 2, a complicated mechanism for precisely driving a relatively large diaphragm is required. May reduce the reliability and cost of the projector. In particular, in the case of the opening / closing aperture mechanism disclosed in Non-Patent Document 1, two drive mechanisms are required at the top and bottom, and problems in terms of reliability and cost become more prominent.

  In addition, as in Patent Documents 2 to 4 and the like, in the method of rotating the polarizing plate or the wave plate, an unnecessary polarizing component is absorbed by the polarizing plate provided on the incident surface of the liquid crystal panel. The characteristics may deteriorate due to heating gradually due to light absorption.

  Therefore, the present invention does not require a complicated mechanism for adjusting the light amount, and does not require heating of the polarizing plate provided on the incident surface of the liquid crystal panel, and the light amount adjustment that can easily adjust the amount of illumination light of the liquid crystal panel or the like. An object is to provide a projector of the type.

  In order to solve the above-described problems, a projector according to the present invention includes a light source, a light modulation device that modulates light emitted from the light source, and an in-plane illuminance distribution of a light beam emitted from the light source. A uniform illumination optical system that makes uniform near the position, and a projection optical system that projects the light modulated by the light modulator, and the uniform illumination optical system has a rod having a reflecting surface on the side surface side. The rod is configured to separate the light beam emitted from the light source into a plurality of partial light beams by reflecting light on the reflecting surface, and in the optical path between the light source and the rod A conversion element is provided, and the polarization conversion element separates light emitted from the light source into first and second polarizations whose polarization directions are orthogonal to each other, and emits the first polarization to the rod side. Polarization separating element and the polarized light A reflection element that reflects at least a part of the second polarized light emitted from the separation element and emits the reflected light toward the rod; the first polarization emitted from the polarization separation element; and the reflection element. And a retardation plate that aligns the polarization direction of the emitted second polarized light. In the projector, the reflective element is configured by a reflective polarizing element, and the reflective polarizing element is supported by a rotation driving mechanism that changes the posture of the reflective polarizing element.

  According to the projector, the retardation plate aligns the polarization directions of the first polarized light emitted from the polarization separating element and the second polarized light emitted from the reflective element. Polarized light aligned in the same direction can be incident on the rod, and the light modulator can be efficiently illuminated only with polarized light in the required polarization direction. In this case, since the rotation drive mechanism changes the posture of the reflective polarizing element, the amount of the second polarized light reflected by the reflective polarizing element can be changed according to the posture of the reflective polarizing element. . Therefore, the amount of illumination light of the light modulation device can be easily and accurately adjusted by a simple rotation drive mechanism that only changes the attitude of the reflective polarization element incorporated in the polarization conversion element. That is, the brightness can be easily set according to the type of image to be projected and the usage environment, and the expressive power of the image can be easily increased.

  In a specific aspect or aspect of the present invention, in the projector, the reflective polarizing element is a reflective polarizing plate. In this case, the amount of light reflected from the second polarized light by the reflective polarizing element and emitted to the rod side can be adjusted over a wide range with good wavelength characteristics. Therefore, the adjustment range of the illumination light quantity of the light modulation device can also be set large.

  In another specific embodiment of the present invention, the reflective polarizing plate is a wire grid polarizer. In this case, the reflective polarizing plate can be made excellent in terms of light resistance and the like.

  In another specific aspect of the present invention, the rotational drive mechanism changes the rotational position around a support axis perpendicular to the reflective polarizing plate while supporting the reflective polarizing plate from the back side. In this case, the posture of the reflective polarizing plate can be directly adjusted by a simple mechanism, and the illumination light quantity of the light modulation device can be accurately adjusted with high flexibility.

  In another specific aspect of the invention, the reflective polarizing element includes a polarization separation film including a multilayer film. In this case, it is possible to reliably adjust the amount of light that is reflected by the reflective polarizing element and is emitted to the rod side.

  In another specific aspect of the invention, the rotation driving mechanism changes an inclination angle of the polarization separation film with respect to an optical axis of the second polarized light incident on the reflective polarizing element. In this case, the posture of the reflective polarizing plate can be directly adjusted by a simple mechanism.

  In another specific aspect of the invention, the rod includes an incident end face having a first partial region and a second partial region, and the polarization separation element is connected to the first partial region and A polarization beam splitter having a first exit surface for emitting the first polarized light into the rod through the first partial region, and a second exit surface for emitting the second polarized light; The polarizing element reflects a predetermined polarization component of the light emitted from the second exit surface of the polarization beam splitter and causes the light to enter the second partial region of the rod. In this case, it is possible to provide an optical unit that is excellent in handleability by integrating the uniform illumination optical system and the polarization conversion element.

[First Embodiment]
FIG. 1 is a diagram illustrating a projector according to a first embodiment of the invention. The projector 10 includes a light source device 20 that generates light source light, an illumination light forming unit 30 that converts the illumination light from the light source device 20 into polarized light in a predetermined direction and makes it uniform, and illumination light that has passed through the illumination light forming unit 30. The divided illumination system 40 that divides the light into three colors of red, green, and blue, the light modulator 50 that is illuminated by the illumination light of each color emitted from the divided illumination system 40, and the modulated light of each color from the light modulator 50 And a projection lens 70 that projects image light that has passed through the cross dichroic prism 60 onto a screen (not shown).

  Here, the light source device 20 includes a lamp main body 21 that forms a substantially dot-like light emitting portion, and an elliptical concave mirror 22 that condenses light source light emitted from the lamp main body 21. Among these, the lamp body 21 is composed of a lamp light source such as a high-pressure mercury lamp, and generates substantially white light source light. The concave mirror 22 reflects the light emitted from the lamp main body 21 so as to be incident on a predetermined position of the illumination light forming unit 30 as a condensed light source light beam SL. Note that various concave mirrors such as a paraboloid, a spherical surface, and an aspherical surface can be used in place of the elliptical concave mirror 22. When such a concave mirror is used, if a condensing lens is arranged between the concave mirror 22 and the illumination light forming unit 30, it is possible to emit the light source light beam SL that is condensed from the light source device 20 at an appropriate convergence angle. It becomes.

  The illumination light forming unit 30 includes a polarization conversion device 31 that is a polarization conversion element for converting the light source light beam SL from the light source device 20 into a specific polarization component, and an operation state of the polarization conversion device 31 (specifically, an illumination light amount). , A rod integrator 33 that separates the light source light beam SL into a plurality of partial light beams, and a superimposing lens 35 that superimposes the many partial light beams on the irradiation target. Among these, the rod integrator 33 and the superimposing lens 35 function as a uniform illumination optical system for making the in-plane illuminance distribution of the light beam uniform on the irradiation target.

  The polarization converter 31 converts the light source light beam SL into a first polarized light (specifically, S-polarized light perpendicular to the paper surface of FIG. 2) and a second polarized light (specifically, P parallel to the paper surface of FIG. 2). A polarization beam splitter 31a that separates components into polarized light) and a polarization direction of the second polarized light transmitted through the polarization beam splitter 31a (that is, parallel to the paper surface) is aligned with a polarization direction of the first polarized light (that is, perpendicular to the paper surface) 1 Reflective polarized light that reflects the second polarized light (in this case, aligned with S polarized light) that has passed through the / 2 wavelength plate 31b and the half wavelength plate 31b with an appropriate reflectance according to its rotational position And a plate 31c.

  2A and 2B are an enlarged plan view and a side view for explaining the structure of the polarization conversion device 31. FIG. Among these, the polarization beam splitter 31a is a prism-type polarization separation element incorporating a polarization separation film 37 made of a dielectric multilayer film, and its first exit surface ES1 is half of the incident end surface 33a of the rod integrator 33, that is, the first. It is joined to one partial area PA1. The polarization beam splitter 31a transmits P-polarized light and reflects S-polarized light in the light source light beam SL. That is, the S-polarized light reflected by the polarization separation film 37 of the polarization beam splitter 31a enters the rod integrator 33 as the first portion L1 through the first exit surface ES1 and the first partial region PA1. On the other hand, the P-polarized light transmitted through the polarization separation film 37 of the polarization beam splitter 31a is emitted as the second portion L2 outside the polarization beam splitter 31a, that is, to the half-wave plate 31b through the second emission surface ES2.

  The half-wave plate 31b is joined to the second exit surface ES2 of the polarization beam splitter 31a. The half-wave plate 31b has an optical axis set in an appropriate direction, and converts the second portion L2 of P-polarized light that has exited the polarization beam splitter 31a through the second exit surface ES2 into S-polarized light. To do.

  The reflective polarizing plate 31c is a wire grid polarizer (reflective element) in which a fine stripe-shaped conductor array is formed on the surface SA of a transparent glass substrate. For example, when the conductor array extends in the AB direction perpendicular to the paper surface. The second portion L2 of S-polarized light having passed through the half-wave plate 31b is almost completely reflected. On the other hand, when the conductor array extends in the CD direction parallel to the paper surface, the second portion L2 of S-polarized light that has passed through the half-wave plate 31b is almost completely transmitted. That is, the reflectance of the second portion L2 by the reflective polarizing plate 31c can be changed from about 0% to about 100 simply by appropriately rotating the reflective polarizing plate 31c about the support axis RA and adjusting the posture at the rotational position. % Can be changed stably and reliably. The S-polarized light reflected by the reflective polarizing plate 31c and partially attenuated, that is, the second portion L2 'enters the rod integrator 33 through the second partial region PA2. On the other hand, S-polarized light that has passed through the reflective polarizing plate 31c, that is, unnecessary light, is guided to an appropriate light-absorbing material or shielding body, and stray light is prevented from being generated.

  In the above description, the wire grid polarizer used as the reflective polarizing plate 31c is, for example, the same inorganic reflective polarizing plate as disclosed in JP-T-2003-502708, JP-T-2003-51818, etc. Thus, polarization separation can be performed with a small loss over a wide wavelength band.

  As the reflective polarizing plate 31c, instead of the wire grid polarizer, for example, an organic polarization separating / reflecting plate disclosed in JP-T-9-506984, JP-A-10-3078, or the like can be used. . Such an organic polarized light separating / reflecting plate is composed of, for example, different polymer materials alternately laminated and stretched in one direction, and one of the polymer materials produces refractive index anisotropy by stretching. If so, reflective polarization separation is possible. Also in this case, as in the case of the wire grid polarizer, the light quantity of the second portion L2 ′, which is S-polarized light to be incident on the rod integrator 33, can be accurately adjusted by appropriately rotating the polarization separation reflector around the vertical axis. Can be adjusted to.

  As described above, the first portion L1 incident on the rod integrator 33 from the polarization beam splitter 31a via the first partial region PA1, and the inside of the rod integrator 33 from the reflective polarizing plate 31c via the second partial region PA2. The first portion L2 ′ incident on the beam is combined with the S-polarized light in the rod integrator 33 and is made uniform.

  Returning to FIG. 1, the rotation drive mechanism 32 includes a stepping motor and the like, and rotates the reflective polarizing plate 31 c in a desired angular direction within the plane. That is, the rotation driving mechanism 32 changes the rotational position around the vertical axis of the reflective polarizing plate 31c by a minute step angle while supporting the reflective polarizing plate 31c from the back side. As a result, as described with reference to FIG. 2, the second portion L2 of the light source light beam SL can be totally reflected or completely transmitted, and the transmittance can be adjusted at these intermediate stages. Can do. That is, the light amount of the first portion L2 'that enters the rod integrator 33 via the reflective polarizing plate 31c varies from approximately zero to the light amount of the first portion L1. Accordingly, in theory, the light source light beam SL can be made to be incident on the rod integrator 33 from the light source light beam SL which has been changed to the S-polarized light by approximately 50%.

  The rod integrator 33 is made of a rectangular glass rod, and propagates from one end to the other while dividing incident light by internal reflection at its four side surfaces 33b. That is, the light converted into a single polarization component through the polarization converter 31 is split into a number of partial light beams through the rod integrator 33. The superimposing lens 35 appropriately converges the light passing through the rod integrator 33 as a whole, and enables superimposing illumination on the light modulation devices of the respective colors provided in the light modulation unit 50. In other words, the illumination light that has passed through the rod integrator 33 and the superimposing lens 35 passes through the divided illumination system 40, which will be described in detail below, and the light modulation device for each color that constitutes the light modulation unit 50, that is, the liquid crystal panels 51b, 51g, 51r for each color. The image forming area is uniformly superimposed and illuminated. Note that the cross-sectional shape of the rod integrator 33 corresponds to the aspect ratio of the projected image, so that the irradiated areas of the liquid crystal panels 51b, 51g, 51r can be illuminated uniformly and efficiently. Yes.

  The divided illumination system 40 includes first and second dichroic mirrors 41a and 41b, reflection mirrors 42a, 42b, 42c, 42d, and 42e, field lenses 43b, 43g, and 43r, and lenses 45a and 45b. Among these, the color separation optical system including the first and second dichroic mirrors 41a and 41b separates the illumination light into three light beams of red light, green light, and blue light. That is, the first dichroic mirror 41a provided on the incident side reflects the blue light LB among the three colors of red, blue, and green (R, G, and B) and transmits the green light LG and the red light LR. The second dichroic mirror 41b is disposed on the optical path of the transmitted lights LG and LR of the first dichroic mirror 41a, reflects the green light LG of the two color lights LG and LR, and transmits the red light LR.

  In the split illumination system 40, the illumination light emitted from the light source device 20 through the illumination light forming unit 30 first enters the first dichroic mirror 41a. The blue light LB reflected by the first dichroic mirror 41a is guided to the first optical path OP1, and enters the field lens 43b for adjusting the incident angle via the reflection mirror 42a, the lens 45a, and the reflection mirrors 42b and 42c. . In addition, the green light LG reflected by the second dichroic mirror 41b out of the color lights LG and LR transmitted through the first dichroic mirror 41a and passed through the reflection mirror 42d and the lens 45b is guided to the second optical path OP2 and reflected by the reflection mirror 42a. And enters the field lens 43g. Further, the red light LR that has passed through the second dichroic mirror 41b is guided to the third optical path OP3, and enters the field lens 43r via the reflection mirror 42e.

  Here, the relay optical system configured to include the lenses 45a and 45b transmits the image by the superimposing lens 35 provided in the illumination light forming unit 30 to the field lenses 43b, 43g, and 43r on the emission side, thereby The use efficiency of light due to the diffusion of light is prevented. The first lens 45a is dedicated to the blue light LB, and the second lens 45b is used for both the green light LG and the red light LR.

  The light modulator 50 includes three liquid crystal panels 51b, 51g, and 51r on which the three colors of illumination lights LB, LG, and LR are incident, and three sets of polarized light that are arranged so as to sandwich the liquid crystal panels 51b, 51g, and 51r. Filters 52b, 52g, and 52r are provided. Here, for example, the blue light LB liquid crystal panel 51b and the pair of polarizing filters 52b and 52b sandwiching the liquid crystal panel 51b constitute a liquid crystal light valve for two-dimensionally modulating the illumination light. Similarly, the liquid crystal panel 51g for green light LG and the polarizing filters 52g and 52g also constitute a liquid crystal light valve, and the liquid crystal panel 51r for red light LR and the corresponding polarizing filters 52r and 52r also have a liquid crystal light valve. Constitute.

  In the light modulation unit 50, the blue light LB guided to the first optical path OP1 enters the image forming area of the liquid crystal panel 51b via the relay lens 45a and the field lens 43b. The green light LG guided to the second optical path OP2 through the relay lens 45b enters the image forming area of the liquid crystal panel 51g via the field lens 43g. The red light LR guided to the third optical path OP3 through the relay lens 45b enters the image forming area of the liquid crystal panel 51r through the field lens 43r. Each of the liquid crystal panels 51b, 51g, and 51r is a non-luminous and transmissive light modulator for changing the spatial distribution of the polarization direction of the incident illumination light, and is incident on each of the liquid crystal panels 51b, 51g, and 51r. The polarization states of the color lights LB, LG, and LR are adjusted in units of pixels in accordance with the drive signals or image signals input as electrical signals to the liquid crystal panels 51b, 51g, and 51r. At that time, the polarization filters 52b, 52g, and 52r adjust the polarization direction of the illumination light incident on the liquid crystal panels 51b, 51g, and 51r, and the light emitted from the liquid crystal panels 51b, 51g, and 51r has a predetermined value. The modulated light in the polarization direction is extracted.

  The cross dichroic prism 60 is a color synthesis optical system, and includes a first dichroic film (specifically a dielectric multilayer film) 61 for reflecting blue light and a second dichroic film (specifically) for reflecting red light. Specifically, a dielectric multilayer film) 62 is arranged in an X shape. The cross dichroic prism 60 reflects the blue light LB from the liquid crystal panel 51b by the first dichroic film 61 and emits the green light LG from the liquid crystal panel 51g via the dichroic films 61 and 62. The red light LR from the liquid crystal panel 51r is reflected by the second dichroic film 62 and emitted to the left in the traveling direction.

  The image light synthesized by the cross dichroic prism 60 in this way is projected as a color image on a screen (not shown) at an appropriate magnification through a projection lens 70 which is a projection optical system.

  FIG. 3 is a block diagram for explaining a part of the signal processing circuit of the projector 10 of FIG. The illustrated partial circuit includes a signal input unit 81, a brightness control signal generation unit 82, a gradation signal formation unit 83, a panel driver 84, and a polarizing plate drive signal formation unit 85. Various video signals such as a video signal and a digital image signal are input to the signal input unit 81. In the signal input unit 81, conversion from an analog video signal to a digital video signal is performed, for example, conversion into a video signal suitable for image processing in the projector 10. The brightness control signal generation unit 82 generates a brightness control signal from the video signal converted into a digital video signal or the like. This brightness control signal is calculated based on the type of video signal and the luminance range, and is used for appropriately adjusting the intensity of illumination light emitted from the light source device 20 according to the projection image. The gradation signal forming unit 83 expands the video signal to an appropriate gradation range based on the brightness control signal or the like. The video signal appropriately expanded in this way is input to the panel driver 84, and display control of each of the liquid crystal panels 51b, 51g, 51r is performed by the panel driver 84. On the other hand, the polarizing plate drive signal forming unit 85 forms a drive signal for appropriately operating the stepping motor or the like of the rotation drive mechanism 32 based on the brightness control signal. The rotation drive mechanism 32 is driven by a drive signal to rotate the reflective polarizing plate 31c in an angular direction corresponding to the brightness control signal and to enter the rod integrator 33, that is, each liquid crystal panel. The illumination light amounts 51b, 51g, and 51r can be adjusted to a state corresponding to the brightness control signal.

  In the above description, the signal processing circuit in FIG. 3 adjusts the illumination light amount of each of the liquid crystal panels 51b, 51g, 51r in accordance with the video signal. However, the user operating the projector 10 determines the illumination light amount. You may enable it to adjust directly, and you may enable it to adjust an illumination light quantity automatically according to the environment (brightness) where the projector 10 is installed.

  Hereinafter, the operation of the projector 10 according to the present embodiment will be described. The illumination light from the light source device 20 is subjected to the illumination light forming unit 30 to have the polarization direction aligned and uniform, and is then color-divided by the first and second dichroic mirrors 41a and 41b provided in the divided illumination system 40. Are incident on the liquid crystal panels 51b, 51g and 51r as the respective color lights LB, LG and LR. Each liquid crystal panel 51b, 51g, 51r is modulated by an image signal from the outside and has a two-dimensional refractive index distribution, and modulates each color light LB, LG, LR in a two-dimensional space in units of pixels. As described above, the color lights LB, LG, and LR that are modulated by the liquid crystal panels 51b, 51g, and 51r, that is, the image light, are combined by the cross dichroic prism 60 and then enter the projection lens 70. The image light incident on the projection lens 70 is projected onto the screen at an appropriate magnification.

  In the projector 10, the illumination light forming unit 30 and the like are operated based on the type of video signal and the luminance range, and the intensity of the illumination light emitted from the light source device 20 is adjusted, and the liquid crystal panels 51b, 51g, 51r are adjusted. Since the gradation can be controlled, it is possible to set the brightness according to the type of projection image and the usage environment, thereby enhancing the expressiveness of the image.

[Second Embodiment]
FIG. 4 is a diagram for explaining a main part of the projector according to the second embodiment. The projector 10 according to the present embodiment is obtained by partially changing the projector 10 according to the first embodiment shown in FIG. 1, and has the same structure as the projector 10 according to the first embodiment with respect to parts that are not particularly described. Common parts are denoted by the same reference numerals, and redundant description is omitted.

  The illumination light forming unit 130 shown in FIG. 4 includes a polarization conversion device 131, a rotation drive mechanism 132, a rod integrator 33, and a superimposing lens (not shown). Among these, the polarization conversion device 131 includes a polarization beam splitter 131c instead of the reflective polarizing plate 31c shown in FIG. Correspondingly, the rotation drive mechanism 132 rotates the polarization beam splitter 131c around a support axis RA 'perpendicular to the paper surface.

  The polarization beam splitter 131c is an oblique incidence type polarizer in which a polarization separation film made of a dielectric multilayer film is formed on the surface SA of a transparent crow substrate, and is S-polarized light that has passed through the half-wave plate 31b, that is, the polarization separation film. The second portion L2 of the polarized light component parallel to can be reflected almost completely. On the other hand, when the polarization beam splitter 131c is rotated clockwise or counterclockwise around a rotation axis perpendicular to the paper surface from the illustrated state, the reflectance of the second portion L2 gradually decreases. If the rotation angle of the polarization beam splitter 131c becomes too large, the reflected light from the polarization beam splitter 131c is not coupled to the rod integrator 33 or is not internally reflected by the side surface 33b of the rod integrator 33, and the light amount control is easy. Therefore, the rotation angle of the polarization beam splitter 131c is set to a certain angle range in which accurate light quantity control is possible.

  In the case of the present embodiment as well, as in the case of using the reflective polarizing plate 31c as in the first embodiment, the polarization beam splitter 131c is appropriately rotated to make the second portion of the S-polarized light incident on the rod integrator 33. The amount of light of L2 ′ can be adjusted up or down.

  In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can implement in a various aspect, For example, the following deformation | transformation is also possible.

  That is, the cross-sectional shape of the rod integrator 33 is not limited to the aspect ratio 9:16 as shown in FIG. In this case, the shape and dimensions of the polarizing beam splitter 31a fixed to the rod integrator 33 and the reflective polarizing plate 31c disposed opposite to the second exit surface ES2 of the polarizing beam splitter 31a are also illumination to be coupled to the rod integrator 33. Adjust appropriately so that the light loss of light does not increase.

  Moreover, the cross-sectional shape of the rod integrator 33 can be changed along the axial direction. That is, it is possible to use a rod integrator whose sectional size changes in a tapered shape.

  Moreover, the half-wave plate 31b can be affixed not to the second exit surface ES2 of the polarization beam splitter 31a but to the incident end surface 33a of the rod integrator 33. In this case, the same operation can be achieved by setting the reference position of the reflective polarizing plate 31c to a rotated position rotated by 90 °.

  In the above embodiment, an example in which the present invention is applied to a transmissive projector has been described. However, the present invention can also be applied to a reflective projector. Here, “transmission type” means that the light valve including the liquid crystal panel is a type that transmits light, and “reflection type” is a type that the light valve reflects light. Means. In the case of a reflection type projector, the light valve can be constituted only by a liquid crystal panel, and a pair of polarizing plates is unnecessary. The light modulation device is not limited to a liquid crystal panel or the like, and may be a light modulation device using a micromirror, for example.

  The projector includes a front projector that projects an image from the direction of observing the projection surface and a rear projector that projects an image from the side opposite to the direction of observing the projection surface. The projector configuration shown in FIG. Is applicable to both.

It is a figure explaining the optical system of the projector which concerns on 1st Embodiment. (A) And (b) is the enlarged view top view and side view explaining the structure of the polarization converter of FIG. It is a block diagram explaining the signal processing circuit of the projector of FIG. It is a figure explaining the principal part of the projector which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector, 20 ... Light source device, 21 ... Lamp main body, 22 ... Concave mirror, 30 ... Illumination light formation unit, 31 ... Polarization conversion apparatus, 31a ... Polarization beam splitter, 31b ... 1/2 wavelength plate, 31c ... Reflective polarization Plate 32... Rotation drive mechanism 33. Rod integrator 33 a. Incident end surface 33 b. Side surface 35. Superimposing lens 40. Split illumination system 41 a. First dichroic mirror 41 b Second dichroic mirror 42 a and 42 b , 42c, 42d, 42e ... reflective mirror, 43b, 43g, 43r ... field lens, 50 ... light modulator, 51b, 51g, 51r ... liquid crystal panel, 52b, 52g, 52r ... polarizing filter, 60 ... cross dichroic prism, 70 ... projection lens, 82 ... control signal generator, 3 ... tone signal forming section, 85 ... polarizer drive signal forming unit, LB, LG, LR ... each color light, OP1 to OP3 ... first through third optical path, SL ... source beam

Claims (7)

A light source; a light modulation device that modulates light emitted from the light source; a uniform illumination optical system that equalizes an in-plane illuminance distribution of a light beam emitted from the light source near a position of the light modulation device; and the light A projection optical system for projecting light modulated by the modulation device,
The uniform illumination optical system has a rod having a reflecting surface on the side surface side,
The rod is formed by separating the light beam emitted from the light source into a plurality of partial light beams by reflecting light on the reflection surface,
In the optical path between the light source and the rod, a polarization conversion element is provided,
The polarization conversion element separates light emitted from the light source into first and second polarizations whose polarization directions are orthogonal to each other, and emits the first polarization to the rod side; and A reflective element that reflects at least a part of the second polarized light emitted from the polarization separation element and emits the reflected light toward the rod, the first polarized light emitted from the polarization separation element, and the reflection A phase difference plate that aligns the polarization direction of the second polarized light emitted from the element, and a projector,
The reflective element is constituted by a reflective polarizing element,
The projector according to claim 1, wherein the reflective polarizing element is supported by a rotation driving mechanism that changes a posture of the reflective polarizing element.   The projector according to claim 1, wherein the reflective polarizing element is a reflective polarizing plate.   The projector according to claim 2, wherein the reflective polarizing plate is a wire grid polarizer.   The rotation drive mechanism changes the rotational position around a support axis perpendicular to the reflective polarizing plate while supporting the reflective polarizing plate from the back side. The projector according to any one of the above.   The projector according to claim 1, wherein the reflective polarizing element includes a polarization separation film including a multilayer film.   The projector according to claim 5, wherein the rotation driving mechanism changes an inclination angle of the polarization separation film with respect to an optical axis of the second polarized light incident on the reflective polarizing element.   The rod includes an incident end face having a first partial region and a second partial region, and the polarization separation element is connected to the first partial region and is inserted into the rod through the first partial region. A polarization beam splitter having a first exit surface for emitting the first polarized light and a second exit surface for emitting the second polarized light, wherein the reflective polarization element is the second of the polarization beam splitter. The projector according to any one of claims 1 to 6, wherein a predetermined polarization component of light emitted from an emission surface is reflected and incident on the second partial region of the rod.

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