JP2008164801A - Illuminator and image projection device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an illuminator capable of uniformly illuminating an image displayed on a liquid crystal display element and projecting image light onto a predetermined surface with bright and high contrast, and an image projection device having the same. <P>SOLUTION: The illuminator has an integrator which guides light from a light source means, and a polarized light separation means which has a polarized light separation surface to transmit light in a predetermined polarization direction out of the light from an optical system for condensing the light from the integrator and to reflect the light in the polarization direction orthogonal thereto, and illuminates a surface to be irradiated with the light through the polarized light separation means. The optical system has a polarized light changing element which emits light after making polarization states uniform, and the integrator on which the light from the light source means is made incident from a rectangular incident surface has two pairs of reflection surfaces facing to each other, where the light from the incident surface is internally reflected. Then, the shapes of the two pairs of reflection surfaces are appropriately set. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illumination device and an image projection device having the illumination device, and is suitable for a liquid crystal projector that projects an enlarged projection image based on a liquid crystal panel (image display element) on a screen surface.

  Conventionally, various image projection apparatuses (liquid crystal projectors) have been proposed in which a projected image based on an image display element such as a liquid crystal panel is enlarged and projected onto a screen surface.

  In this image projection apparatus, an illuminating apparatus using a rod-like integrator using an inner surface reflection for light guiding made of an elliptical mirror (reflector) and a glass material is known in order to illuminate a liquid crystal panel uniformly and with high light use efficiency. (Patent Documents 1 and 2).

  Among them, in Patent Document 2, a light beam from a light source is reflected and collected by a reflector (reflecting umbrella) and is incident on a light incident surface of a rod-shaped rod (integrator) having a polygonal cross section and an inner reflection surface.

  Then, the light beam from the light exit surface of the rod is separated into incident light through a relay lens and emitted through a polarization conversion element, and is incident on a polarization beam splitter.

And the liquid crystal panel provided on the to-be-irradiated surface was illuminated with the light via the polarization beam splitter, and the image projection apparatus which projected the image information displayed on the liquid crystal panel on the screen surface with the projection lens is disclosed.
Japanese Patent Application Laid-Open No. 07-098479 JP 2001-215613 A

  In recent years, image projection apparatuses are required to have a bright projected image and a good image contrast.

  The rod in the illumination device disclosed in Patent Document 2 increases the interval between the reflecting surfaces from the incident end surface of the rod toward the exit end surface, thereby increasing the light incident on the polarization separation surface (polarization selection surface). The angle is reduced to improve the polarization separation performance on the polarization separation surface.

  In Patent Document 2, a surface defined by the normal line of the polarization separation surface and the central axis of the illumination light beam is defined as an incident surface. A direction parallel to the incident surface and orthogonal to the central axis is defined as an x axis, and a direction orthogonal to the x axis and the central axis is defined as a y axis. At this time, the direction in which the distance between the reflecting surfaces of the rods is widened is the y-axis direction.

  In Patent Document 2, the light reflection direction by the polarization separation surface of the polarization beam splitter is parallel to the x-axis, and the incident angle distribution is not improved in the x-axis direction by the rod.

  The polarization separation performance on the polarization separation surface is greatly adversely affected in the x-axis direction where the angle of incidence on the polarization separation surface is larger than the design value. For this reason, since the incident angle distribution in the x-axis direction is not improved as in this example, this method deteriorates the polarization separation performance.

  As a result, polarized light is not sufficiently separated on the polarization separation surface of the polarization beam splitter, light leakage occurs, and the image contrast is lowered in image projection using polarized light.

  An object of the present invention is to provide an illuminating device capable of uniformly illuminating an image displayed on an image display element, and capable of projecting on a predetermined surface with high brightness and high contrast, and an image projecting device having the same. .

The lighting device of the present invention is
Light source means;
An integrator for guiding light from the light source means;
An optical system for collecting the light from the integrator;
Polarization separation means having a polarization separation surface that transmits light in a predetermined polarization direction out of the light from the optical system and reflects light in a polarization direction orthogonal thereto,
In an illumination device configured to illuminate a surface to be irradiated with light via the polarization separation means,
A surface formed by the optical axis of the optical system and the normal line of the polarization separation surface is a first plane,
When a plane perpendicular to the first plane and including the optical axis is a second plane,
The optical system has a polarization conversion element that collects the light from the integrator and emits the light with the polarization state aligned,
The integrator makes light from the light source means incident from a rectangular incident surface, has two pairs of reflective surface pairs facing each other from which the light from the incident surface is internally reflected, and the light reflected from the inner surface is rectangular. It is emitted from the exit surface,
The two pairs of reflecting surfaces are perpendicular to each other;
In at least one of the reflecting surface pairs, the interval between the two reflecting surfaces changes along the light emitting direction, and the rate of change in the interval between the reflecting surfaces of the two pairs of reflecting surfaces changes in the first plane direction. It is characterized in that the rate direction is larger than the second plane direction.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device which can illuminate the image displayed on the image display element uniformly, and can project on a predetermined surface with a bright high contrast, and an image projection apparatus having the same are obtained.

  FIG. 1 is a schematic diagram of a main part of a first embodiment of an image projection apparatus having an illumination device of the present invention.

  FIG. 2 is a schematic view of a main part in a cross section including the optical axis La of FIG. 1 and orthogonal to the paper surface.

  1 and 2, reference numeral 1 denotes a light source means, which is a light source that emits white light from a high-pressure mercury lamp (which may be a metal halide lamp or the like). Reference numeral 2 denotes a reflector, which is composed of a spheroid (concave mirror) that efficiently reflects the light beam from the light source means 1.

  Reference numeral 3 denotes an integrator, which is composed of a solid or hollow lot member, guides the light beam from the light source means 1, and adjusts the emission angle (outgoing angle) of the emitted light while making the light intensity distribution of the light beam uniform. is doing.

  3in is an entrance surface of an integrator (rod, rod integrator, glass rod) 3 and 3out is an exit surface of the integrator 3, both of which are rectangular.

  Reference numeral 4 denotes a first lens group that collects the light flux from the integrator 3.

  Reference numeral 5 denotes a polarization conversion element, which emits light from the first lens group 4 in the same polarization state, for example, as P-polarized light.

  Reference numeral 6 denotes a second lens group, which collects light having a uniform polarization state from the polarization conversion element 5. The first lens group 4, the polarization conversion element 5, and the second lens group 6 constitute a part of the optical system OP.

  Reference numeral 7 denotes a polarization separation means (polarization beam splitter), which has a polarization separation surface 8, thereby reflecting light in a predetermined polarization state and transmitting light in a polarization state orthogonal thereto.

  Reference numeral 9 denotes a reflective liquid crystal panel (light valve, hereinafter also referred to as “panel”) as an irradiated object (image display element).

  The panel 9 has a rectangular shape having long sides in the plane of FIG. Pr is a projection optical system that projects image information of the single-panel panel 9 onto the screen S. La is the optical axis (center axis) of the optical system OP. The optical axis La coincides with the optical axes of the first lens group 4 and the second lens group 6. The focal point of the elliptical mirror 2 is located on the optical axis La.

  In this embodiment, the optical axis La is the Z axis. A surface (in the drawing of FIG. 1) formed by the Z axis (optical axis La) and the normal line of the polarization separation surface 8 is defined as an XZ plane (first plane). The direction orthogonal to the Z axis in the XZ plane is taken as the X axis. In addition, a plane including the Z axis (optical axis La) and orthogonal to the XZ plane (within the paper surface of FIG. 2) is defined as a YZ plane (second plane). The direction perpendicular to the Z axis in the YZ plane is taken as the Y axis.

  In this embodiment, the light beam from the light source means 3 passes through the integrator 3 and the first lens group 4, becomes P-polarized light by the polarization conversion element 5, passes through the second lens group 6, and enters the polarization separation element 7. The panel 9 provided on the irradiated surface is illuminated with light through the polarization separation surface 8 of the polarization separation element 7.

  The P-polarized light incident on the panel 9 is modulated by the image information and becomes S-polarized light. S-polarized light is reflected by the polarization separation surface 8 of the polarization separation element 7 and guided to the projection optical system Pr.

  The projection optical system Pr projects image information based on the panel 9 onto a screen (on a predetermined surface) S.

  The shape of the integrator 3 according to the first embodiment will be described.

  FIG. 5 is a perspective view of a main part of the integrator 3. FIG. 4 is an explanatory view showing the shape of the exit surface 3out of the integrator 3. FIG. FIG. 3 is an explanatory view showing the shape of the incident surface 3in of the integrator 3. FIG. The integrator 3 is made of a solid internal reflection lot member.

  The integrator 3 makes light from the light source means 1 incident from a rectangular incident surface 3in. There are two pairs of reflective surfaces facing each other (light reflecting surface pairs 3a1, 3a2 and light reflecting surface pairs 3b1, 3b2) from which the light from the incident surface 3in is internally reflected, and the light reflected from the inner surface is emitted from the rectangular light emitting surface 3out. ing. The two pairs of reflecting surfaces are perpendicular to each other.

  Among these, at least one of the reflecting surface pairs (the reflecting surfaces 3a1 and 3a2 in the first embodiment) changes the distance between the two reflecting surfaces 3a1 and 3a2 along the light emission direction (Z direction).

  The rate of change in the distance between the reflecting surfaces of the two pairs of reflecting surfaces is greater in the direction of the rate of change in the first plane direction (X direction) than in the second plane direction (Y direction).

  The shape of the exit surface 3out of the integrator 3 is substantially similar to the image forming area of the panel 9. Here, the panel image forming region is a region where a liquid crystal layer to which a voltage is applied based on an image signal is arranged when the panel is a liquid crystal panel. Note that the exit surface 3out of the integrator 3 here is preferably similar to the shape having a margin in the vertical direction and the horizontal direction as compared with the image forming area. It is desirable to have a similar shape (or a similar shape).

A first plane direction of the incident surface 3in of the integrator 3,
The lengths in the second plane direction are a ′ and b ′, respectively.

  The lengths of the exit surface 3out of the integrator 3 in the first plane direction and the second plane direction are a and b, respectively.

At this time, a ′ / a <b ′ / b
Is satisfied.

  That is, the rate of change in the distance between the reflecting surfaces of the two pairs of reflecting surfaces (the reflecting surfaces 3a1, 3a2 and the reflecting surfaces 3b1, 3b2) is the second rate of change a ′ / a in the first plane direction (X direction). The rate of change b ′ / b in the plane direction (Y direction) is large.

  The specific length relationship between each side of the entrance surface 3in and the exit surface 3out of the integrator 3 according to the first embodiment is as follows.

a ′ <a, b ′ = b (1)
Ａ a '/ a <b' / b (2)
The integrator 3 is a hexahedron having a shape in which, in the first plane (XZ plane), the interval between the reflecting surfaces 3a1 and 3a2 facing in the x direction gradually expands in the z direction symmetrical to the z axis.

  The short side direction 3x of the integrator 3 is parallel to the x-axis direction.

  Next, the configuration of the polarization conversion element 5 will be described.

  FIG. 19 is an enlarged explanatory view of a part of the polarization conversion element 5.

  The polarization conversion element 5 includes a plurality of units each including a polarization separation film 5a, a reflection film 5b, and a half phase plate 5c.

  The incident light L1 is separated into P-polarized light Lp and S-polarized light Ls by the polarization separation film 5a. The S-polarized light Ls is reflected by the reflective film 5b in the same direction as the P-polarized light Lp, and a half-phase plate 5c is disposed on the exit side of the S-polarized light Ls to convert it into the same polarization state as the P-polarized light. Light is aligned in the polarization state.

  In FIGS. 1 and 2, of the two focal points of the elliptical reflector 2, the focal point on the light emission side is the second focal point, and the focal point close to the other reflecting surface is the first focal point.

  At this time, the position of the light emitting surface of the light source means 1 is adjusted so as to include the first focal position. The integrator 3 is arranged so that the position of the incident surface 3in includes the second focal point of the reflector 2.

  The first lens group 4 has three lenses having positive refractive power. The second lens group 6 has two lenses having positive refractive power.

  As shown in FIG. 2, the light emitted from the light source means 1 is condensed and incident on the incident surface 3 in of the integrator 3, and is divided into a plurality of light beams by repeating total reflection (internal reflection) in the integrator 3. Is done.

  Here, the luminous flux is divided by the difference in the number of reflections of total reflection inside the integrator 3, and is divided into 0-time reflected light, 1-time reflected light, and 2-time reflected light.

  In this embodiment, up to twice reflected light is used for illumination as an effective light beam. However, in a brighter illumination system, a light beam that is reflected three times or more may be used. The plurality of divided light beams enter the first lens group 4 and are condensed as a light source image by the first lens group 4 toward the center of each pitch of the polarization conversion element 5.

  The light incident on the polarization conversion element 5 is emitted after being converted into light having a polarization direction in a predetermined direction, and is incident on the second lens group 6. The plurality of light beams incident on the second lens group 6 are emitted as telecentric light by the positive refractive power of the second lens group 6 and are guided by being superimposed on the surface of the panel 9.

  In FIG. 2, an optical action is described in which the light beam is divided into a plurality of parts by the integrator 3 and then condensed on the panel 9 by the first and second lens groups 4 and 6.

  The light having a larger angle of light incident on the integrator 3 has a greater number of total reflections in the integrator 3 and shows an optical action in which the light beam is divided by the number of reflections.

  FIGS. 6 and 7 are diagrams showing the emission angle range of the light once reflected in the integrator 3 out of the light emitted from the integrator 3, in an xz section and a yz section.

The angle range (radiation angle) of the light emitted from the integrator 3 is defined as an angle θ1 with respect to the x direction in FIG. 1 and an angle θ2 with respect to the y direction in FIG. At this time, as shown in FIGS. 6 and 7, the reflecting surfaces 3 a 1 and 3 a 2 of the integrator 3 are inclined in the x direction. For this,
θ1 <θ2
The relationship becomes true.

  In general, with respect to the optical characteristics of the polarization beam splitter 7, the polarization separation characteristics deteriorate as the range of the angle of light incident on the polarization separation surface 8 changes greatly with reference to 45 degrees. Therefore, in an image projection apparatus having an illumination system that separates and combines light using the polarization beam splitter 7, light leakage occurs and the contrast characteristics of the projected image deteriorate.

  For this reason, in this embodiment, the reflecting surfaces 3a1 and 3a2 of the integrator 3 are inclined with respect to the optical axis in order to reduce the angle range incident on the polarization splitting surface 8.

That is, when the length of the entrance surface 3in in the x direction is a 'and the length of the exit surface 3out is a, 0.4 <a' / a <0.9
It is trying to become.

  Here, if the value falls below the lower limit value, the illumination light beam in the x direction is narrowed, and the reduction in the amount of light incident on the panel 9 is significantly increased. If the value exceeds the upper limit, the angle of light incident on the polarization splitting surface 8 increases, and the contrast characteristics of the image become insufficient.

  Numerical examples of Example 1 are described below.

  i represents the order of the surfaces from the light source means, Ri represents the i-th radius of curvature, di represents the distance between the i-th surface and the i + 1-th surface, and Ni represents the refractive index based on the d-line.

-Reflector: Ellipse radius of curvature R = -18.10606
k (conic coefficient) = −0.657080
・ Lighting system:
First lens group (from light source means 1 side) 4
Surface No. R (radius of curvature) d (thickness) Refractive index N
1: 394.78915 7.000000 1.834000
2: 43.51512 0.150000
3: −57.08632 7.000000 1.834000
4: 6917.23516 36.866914
5: 3836.15913 8.000000 1.834000
6: 66.52209
Second lens group (from light source means 1 side) 6
Surface No. R (radius of curvature) d (thickness) Refractive index N
7: −132.78608 6.000000 1.516330
8: 274.41559 26.938005
9: −56.73668 12.000000 1.516330
10: 0
・ Integrator 3
Refractive index N 1.51633
z-direction length: 57.5 mm
Entrance end face 3in: short side length 4.175 mm (= a ')
Long side length 8.175 mm (= b ')
Output end face 3out: Short side length 6.131 mm (= a)
Long side length 8.175 mm (= b)
a '/ a = 0.68 <b' / b = 1
With the above-described configuration, this embodiment realizes an image projection apparatus that can maintain both the image contrast and the brightness characteristics well.

  In the present embodiment, the integrator 3 may be constituted by a hollow reflecting member instead of a solid rod member.

  FIG. 8 is a perspective view of the integrator 10 made of a hollow.

  In the hollow integrator 10, the reflecting surfaces 10a1 and 10a2 are arranged to face each other in the x direction. The reflecting surfaces 10b1 and 10b2 are arranged so as to face each other in the y direction. With respect to the x direction, the reflecting surfaces 10a1 and 10a2 are inclined with respect to the central axis of the illumination light beam, and the reflecting surface pairs 10a1 and 10a2 are configured to gradually spread toward the light exit side symmetrically with respect to the z axis.

  By the reflecting surfaces 10a1 and 10a2 facing each other, reflection is repeated, and incident light can be divided into a plurality of light fluxes depending on the number of reflections.

  Accordingly, the same optical action as in the first embodiment can be obtained. Also, unlike a solid integrator, it is lightweight because it is hollow.

  Further, it is possible to make the image contrast variable by adjusting the angle of the reflecting surfaces 10a1 and 10b2 facing the x direction. Increasing the tilt angle increases the image contrast.

  In this embodiment, as shown in FIG. 9, a diaphragm (light limiting means, diaphragm means, light control) that restricts the light beam to the light incident side of the polarization conversion element 5 between the first lens group 4 and the polarization conversion element 5. (Means) 11 may be provided. FIG. 10 is an explanatory diagram of the aperture shape of the diaphragm 11 at this time.

  At this time, by reducing the light at the four corners in the diagonal direction, it is possible to further improve the image contrast while minimizing the decrease in brightness.

  As shown in FIG. 11, a diaphragm 12 may be provided between the reflector 2 and the integrator 3. FIG. 12 is an explanatory diagram of the aperture shape of the diaphragm 12 used at this time.

  Similar to FIG. 9, by reducing the light at the four corners in the diagonal direction, it is possible to further improve the image contrast while minimizing the decrease in brightness.

  Embodiment 2 of the lighting device of the present invention will be described. The basic configuration of the second embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, and the difference is the configuration of the integrator 3.

  FIG. 13 is an explanatory diagram of the entrance surface 16in and the exit surface 16out of the integrator 16 used in Embodiment 2 of the present invention.

  FIG. 14 is a perspective view of a main part of the integrator 16 used in the second embodiment.

  As shown in FIG. 13, the integrator 16 used in the second embodiment has a length in the x direction of the entrance surface 16in of the integrator 16 as a ', a length in the y direction as b', and a length in the x direction of the exit surface 16out. Is a, and the length in the y direction is b. At this time, the length a 'in the x direction and the length b' in the y direction of the incident surface 16in of the integrator 16 are both shorter than those on the exit side 16out, and the following relationship is satisfied.

a ′ <a, b ′ <b (3)
a ′ / a <b ′ / b (2)
Thereby, both the x direction and the y direction of the angle components incident on the polarization separation surface 8 of the polarization beam splitter 7 can be set to optimum angles. The image contrast characteristics can be improved by setting the angle according to the angle characteristics of the polarizing beam splitter 7 in the x and y directions. Further, as shown in the conditional expression (2), since the opening of the incident surface is narrower in the x direction than in the y direction, the incident angle range in the x direction of the polarization beam splitter 7 can be further reduced, so that the contrast of the image The characteristics can be effectively improved.

  Embodiment 3 of the lighting device of the present invention will be described. The basic configuration of the third embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, and the difference is the configuration of the integrator 3.

  FIG. 15 is an explanatory diagram of the entrance surface 26in and the exit surface 26out of the integrator 26 used in Embodiment 3 of the present invention.

  FIG. 16 is a perspective view of a main part of the integrator 26 used in the third embodiment.

  As shown in FIG. 15, the integrator 26 used in the third embodiment has a length in the x direction of the incident surface 26in of the integrator 26, a length of b 'in the y direction, and a length of the outgoing surface 26out in the x direction. The length is a, and the length in the y direction is b. At this time, the entrance surface 26in and the exit surface 26out of the integrator 26 have the same length in the x direction, but the lengths in the y direction are different, and the following conditional expression is satisfied.

a '= a (4)
b '> b (5)
∴a '/ a <b' / b (2)
The integrator 26 of this embodiment is advantageous in terms of brightness because the incident aperture in the y direction is widened. At this time, of the angle components incident on the polarization beam splitter 7, only the angle θ2 in the y direction increases, and the angle θ1 does not increase in the x direction.

  For this reason, the image contrast characteristics are not greatly deteriorated.

  This embodiment is suitable when importance is attached to the brightness of an image.

  FIG. 17 is a schematic view of the essential portions of an image projection apparatus according to Embodiment 4 of the present invention.

  Embodiment 4 is an image projection apparatus that projects a three-plate panel for Red (Red), Green (Green), and Blue (Blue) onto a screen by a projection optical system.

  The illumination device of the fourth embodiment uses any one of the illumination devices of the first to third embodiments.

  17 shows the inside of the xz plane of FIG. 1, and members shown by reference numerals 1 to 6 and La in the drawing are the same as those in FIG.

  In FIG. 17, reference numeral 40 denotes a dichroic mirror that reflects Red and Blue light out of light from the light source means 1 and transmits Green light. Reference numerals 41 and 42 denote polarization beam splitters. 45 is a green reflective panel, 46 is a red reflective panel, and 47 is a blue reflective panel.

  Reference numeral 43 denotes a dichroic prism having a polarization separation function in the Red band.

  FIG. 18 is a schematic diagram of the spectral characteristics of the polarization separation surface 43 a of the dichroic prism 43. The polarization separation surface 43a transmits red P-polarized light, reflects red S-polarized light, transmits blue light regardless of the polarization state, and reflects green light regardless of the polarization state.

  Reference numeral 44 denotes a wavelength-selective phase plate that rotates the polarization direction of the red light by 90 degrees and does not rotate blue. A projection optical system 48 projects images on the panels 45, 46, and 47 toward the screen S.

  The light emitted from the light source means 3 passes through the members 3 and 4, becomes P-polarized light by the polarization conversion element 5, and is guided to the panels 45 to 47 by the second lens group 6. The dichroic mirror 40 reflects Red and Blue light and transmits Green light.

  The green light transmitted through the dichroic mirror 40 transmits the p-polarized light of the polarization beam splitter 41, passes through the polarization separation surface 41a that reflects the s-polarized light, enters the green panel 45, undergoes image modulation, and is converted into s-polarized light. Become. The image-modulated Green S-polarized light is reflected by the polarization separation surface 41 a of the polarization beam splitter 41, enters the dichroic prism 43, is reflected by the polarization separation surface 43 a of the dichroic prism 43, and is guided to the projection optical system 48.

  Of the P-polarized light reflected by the dichroic mirror 40, the red light is rotated by 90 degrees by the wavelength-selective phase plate 44 to become S-polarized light, and is reflected by the polarization separation surface 42a of the polarizing beam splitter 42 and is reflected by the red panel. 46.

  The red S-polarized light incident on the red panel 46 undergoes image modulation, becomes P-polarized light, passes through the polarization separation surface 42 a, and enters the dichroic prism 43.

  The red P-polarized light passes through the polarization separation surface 43 a of the dichroic prism 43 and is guided to the projection optical system 48.

  Further, the blue P-polarized light of the light reflected by the dichroic mirror 40 is transmitted by the wavelength-selective phase plate 44 without changing the polarization direction, is transmitted through the polarization separation surface 42a of the polarization beam splitter 42, and the blue panel. 47 is incident. The blue P-polarized light incident on the panel 47 is image-modulated by the panel 47 to become S-polarized light, reflected by the polarization separation surface 42 a of the polarization beam splitter 42, and guided to the dichroic prism 43.

  The blue S-polarized light passes through the polarization separation surface 43 a of the dichroic prism 43 regardless of the polarization, and is guided to the projection optical system 48.

  The projection optical system 48 projects an image led to the panels 45 to 47 on the screen S.

  In this embodiment, the illumination system is downsized by using the color separation / synthesis systems 40 to 44 shown in FIG.

1 is a schematic diagram of a configuration in an xz section of Example 1 of the present invention. Schematic configuration of the first embodiment of the present invention in the yz section FIG. 3 is a shape diagram of the entrance surface of the integrator according to the first embodiment of the present invention. FIG. 4 is a shape diagram of the exit surface of the integrator according to the first embodiment of the present invention. The perspective view of the integrator of Example 1 of this invention Optical Action Diagram at xz Section in Integrator of Example 1 of the Present Invention Optical Action Diagram at yz Section in Integrator of Example 1 of the Present Invention The perspective view of the integrator of another form of Example 1 of the present invention The block diagram of the other form in Example 1 of this invention Drawing of the aperture used in FIG. The block diagram of the other form in Example 1 of this invention Drawing of the aperture used in FIG. Optical Action Diagram at yz Section in Integrator of Embodiment 2 of the Present Invention The perspective view of the integrator of Example 2 of this invention FIG. 6 is a diagram of the incident surface and the output surface of the integrator according to the third embodiment of the present invention. The perspective view of the integrator of Example 3 of this invention Configuration diagram of Embodiment 4 of the present invention FIG. 17 is a characteristic diagram of a dichroic prism having a polarization separation function only in the Red band. Explanatory drawing of the polarization conversion element of FIG.

Explanation of symbols

La: Optical axis Pr of the optical system: Projection optical system S: Screen 1: Light source means 2: Reflector 3: Integrator 4: First lens group 5: Polarization conversion element 6: Second lens group 7: Polarization separation means 8: Polarization Separation surface 9: Panel 10: Integrator 11: Diaphragm 12: Diaphragm 13: Central axis 14 of illumination system: Light source 16: Integrator 26: Integrator 40: Dichroic mirror 41: Polarizing beam splitter 42: Polarizing beam splitter 43: Polarizing only in the red band Dichroic mirror 44 having separation action: Wavelength selective phase plate 45: Green panel 46: Red panel 47: Blue panel 48: Projection optical system

Claims (8)

Light source means;
An integrator for guiding light from the light source means;
An optical system for collecting the light from the integrator;
Polarization separation means having a polarization separation surface that transmits light in a predetermined polarization direction out of the light from the optical system and reflects light in a polarization direction orthogonal thereto,
In an illumination device configured to illuminate a surface to be irradiated with light via the polarization separation means,
A surface formed by the optical axis of the optical system and the normal line of the polarization separation surface is a first plane,
When a plane perpendicular to the first plane and including the optical axis is a second plane,
The optical system has a polarization conversion element that collects the light from the integrator and emits the light with the polarization state aligned,
The integrator makes light from the light source means incident from a rectangular incident surface, has two pairs of reflective surface pairs facing each other from which the light from the incident surface is internally reflected, and the light reflected from the inner surface is rectangular. It is emitted from the exit surface,
The two pairs of reflecting surfaces are perpendicular to each other;
In at least one of the reflecting surface pairs, the interval between the two reflecting surfaces changes along the light emitting direction, and the rate of change in the interval between the reflecting surfaces of the two pairs of reflecting surfaces changes in the first plane direction. A lighting device characterized in that a rate direction is larger than a direction of the second plane. A first plane direction of an incident surface of the integrator;
The lengths in the second plane direction are a ′, b ′,
When the lengths of the output plane of the integrator in the first plane direction and the second plane direction are a and b, respectively, a ′ / a <b ′ / b
The lighting device according to claim 1, wherein the following condition is satisfied. The lengths a ′, a, b ′, b are a ′ <a
b '= b
The lighting device according to claim 2, wherein: The lengths a ′, a, b ′, b are a ′ <a
b '<b
The lighting device according to claim 2, wherein: The lengths a ′, a, b ′, b are a ′ = a
b '> b
The lighting device according to claim 2, wherein:   The illumination device according to any one of claims 1 to 5, wherein a light restricting means for restricting a part of the light flux is provided on a light incident side of the polarization conversion element.   6. The illumination device according to claim 1, further comprising a light limiting unit configured to limit a part of a light beam between the light source unit and the integrator.   8. An image projection apparatus comprising: the illumination device according to claim 1; and a projection optical system that projects an image display element illuminated with a light beam from the illumination device onto a predetermined surface. .