JP5393055B2 - Illumination optical system and image projection apparatus using the same - Google Patents

Description

  The present invention relates to an illumination optical system that illuminates a surface to be illuminated, and an image projection apparatus.

In an image projection apparatus such as a projector, an integrator optical system has been used to illuminate a liquid crystal panel. For example, in the projector disclosed in Patent Document 1, a light beam from a light source is guided to a liquid crystal panel through two lens arrays and a biconvex condenser lens. With this configuration, the uniformity of illuminance on the liquid crystal panel is improved by superimposing a plurality of light beams divided by the lens array on the liquid crystal panel.
Japanese Unexamined Patent Publication No. 09-127610 (paragraph 0018, FIG. 3)

  However, when a plurality of light beams emitted from the lens array are superimposed on the liquid crystal panel using a biconvex lens as described in Patent Document 1, the peripheral portion of the liquid crystal panel becomes slightly dark due to the influence of aberration. It was.

  Therefore, the present invention provides an illumination optical system capable of reducing (suppressing) a light amount drop at the periphery of a liquid crystal panel (illuminated surface) and illuminating the illuminated surface with a more uniform illuminance. Objective.

In order to solve the above problems, an illumination optical system of the present invention includes a condensing optical system that converts a light beam emitted from a light source into a convergent light beam, a first lens array that divides the converged light beam into a plurality of light beams, and 2 An illumination optical system including a condenser optical system including a plurality of positive lenses and superimposing the plurality of light beams on an illuminated surface, wherein the two positive lenses each have a higher positive refractive power. Of the two positive lenses, the refractive power of the positive lens arranged on the light source side is φ1, and the refractive power of the positive lens arranged on the illuminated surface side is φ2. And when
0.4 <φ1 / φ2 <0.8
It is characterized by satisfying the relationship .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the illumination optical system which can perform illumination with the high uniformity of the illumination intensity on a to-be-illuminated surface.

  An image projection apparatus according to this embodiment includes an image display element such as a liquid crystal panel, an illumination optical system that illuminates the image display element, and a projection optical system that projects image light from the image display element onto a screen or the like. Projector. Embodiments of an image projection apparatus according to the present invention will be described below in detail with reference to the drawings.

Example 1
1 and 2 are configuration diagrams of the illumination optical system according to the first embodiment of the present invention. 0 is an optical axis of the illumination optical system (center axis of the illumination light beam), 1 is a light source, and 2 is a parabolic reflector (parabolic mirror, parabolic reflecting surface). Reference numeral 3 denotes a condensing lens (condensing optical system) that converts a parallel light beam from the reflector 2 into a condensed light beam (convergent light beam). The reflector 2 and the condenser lens 3 may be replaced with an elliptical mirror that converts the light beam from the light source 1 into a condensed light beam. Reference numeral 4 denotes a first fly-eye lens (first lens array) having a plurality of minute lenses (lens cells) arranged two-dimensionally in the zy plane. The first fly-eye lens splits the light beam from the condensing lens 3 into a plurality of light beams while converting the light beam from the condensing lens 3 into a substantially parallel light beam in the xz plane. Reference numeral 5 denotes a second fly-eye lens (second lens array) having a minute lens corresponding to each minute lens of the first fly-eye lens. The light flux from the first fly-eye lens is substantially parallel in the yz plane. Convert to luminous flux. A polarization conversion element 6 has a function of aligning the polarization direction of the light beam emitted from the second fly-eye lens 5 (aligning with the polarization separation prism 9 at the S-polarization or P-polarization). Here, due to the action of the first fly-eye lens (or the first and second fly-eye lenses), the number corresponding to the plurality of light beams in the vicinity of the second fly-eye lens or the polarization conversion element. A plurality of light source images are formed. 7 is a first condenser lens, 8 is a second condenser lens, 9 is a polarization separation prism (polarization beam splitter) having a polarization separation surface 11, and 10 is a liquid crystal panel (panel, image display element, reflective liquid crystal display element). It is. The first condenser lens 7 and the second condenser lens 8 are configured such that a plurality of light beams emitted from the polarization conversion element (second fly-eye lens) are superimposed on the liquid crystal panel (illuminated surface) 10. Improves uniformity of illuminance on the LCD panel.

  Here, the illumination optical system of the present invention is an optical system that guides the light flux from the light source to the liquid crystal panel, that is, from the reflector 2 (or the condensing lens 3) to the second condenser lens 8 (or the polarization separating prism 9). Point to.

  The x-axis, y-axis, and z-axis directions described in FIGS. First, let the optical axis of this illumination optical system be the z-axis. Next, when the surface defined by the normal line of the polarization separation surface 11 of the polarization separation prism 9 and the central axis O (z axis) of the illumination light beam is defined as the first plane, it is parallel to the first plane and perpendicular to the z axis. Is the y-axis. A direction perpendicular to both the y-axis and the z-axis is taken as the x-axis. As shown, FIG. 1 is a cross-sectional view (schematic configuration diagram) in the xz section of the illumination optical system of the first embodiment, and FIG. 2 is a cross-sectional view (schematic configuration diagram) in the yz section. It is.

  Next, a perspective view of the first fly-eye lens is shown in FIG. 3, and a perspective view of the second fly-eye lens is shown in FIG. The center of curvature of each microlens (lens cell) of the first fly-eye lens 4 is eccentric to the outside (the center of curvature of each microlens is outside in the x direction with respect to the center of the outer frame of each microlens). In the present embodiment, the thickness of the first fly-eye lens increases toward the outer side in the x-axis direction in order to eliminate the step at the boundary portion between the micro-lenses while decentering each micro-lens in the x-axis direction. . In the second fly-eye lens 5, each microlens is decentered in the y-axis direction (the optical axis of the microlens is relative to the center of the outer frame of the microlens). In order to eliminate the step at the boundary between the micro lenses while decentering the center of curvature of the micro lenses outward with respect to the center of the outer frame of each micro lens, the second fly-eye lens is arranged in the y-axis direction. The thickness increases toward the outside.

  The first and second fly-eye lenses will be described in detail with reference to FIG. In FIG. 5, reference numerals 71, 72, 73, and 74 denote minute lenses constituting the first fly-eye lens 4, A is the center of the minute lens 73 (center of the outer frame of the minute lens 73), and L0 is the lens. A light ray incident on A, O 1, is the center of curvature of the micro lens 73. Although this curvature center O1 has come out of the outside of the micro lens 73, it is not restricted to this, and the curvature center O1 may exist in the inside of the micro lens 73, and it is outside (x) like a present Example. It may exist on the outside (in the axial direction).

  Here, the light ray L0 incident on the central portion A of the micro lens 73 will be described. The light beam L0 that has been focused by the front-stage condenser lens 3 enters the center A of the minute lens 73 of the first fly-eye lens 4 while approaching the optical axis O. As described above, since the optical axis of the micro lens 73 is decentered outward in the x-axis direction, the light beam L0 incident on the micro lens 73 is refracted and parallel to the optical axis O (substantially parallel) in the xz cross section. ) To be emitted from the first fly-eye lens. However, the first fly-eye lens 4 gives a refraction action in the xz section to L0 passing through the center A of the micro lens 73, but does not particularly act in the yz section. Therefore, the light beam L1 emitted from the first fly-eye lens 4 is parallel to the optical axis O in the xz section, but is not parallel to the optical axis O in the yz section (inclined in a direction approaching the optical axis). Is).

  Therefore, the second fly-eye lens 5 is configured such that the light beam passing through the center of the minute lens in the second fly-eye lens is parallel to the optical axis O in the yz section.

  Here, since the distance from the condensing lens to the second fly's eye lens is longer than the distance from the condensing lens to the first fly's eye lens, the luminous flux emitted from the second fly's eye lens is in the y-axis direction ( The width in the yz section is narrower than the width in the x-axis direction (in the xz section). The y-axis direction in which the width becomes narrower and the normal direction of the polarization separation surface 11 described above exist in the same plane (within the yz cross section), thereby enhancing the polarization separation characteristics of the polarization separation prism.

  Next, the configuration of the condenser lens (condenser optical system, first and second condenser lenses) of this example will be described in detail with reference to FIG. In Example 1, both the first and second condenser lenses are plano-convex lenses, and these condenser lenses are arranged so that their convex surfaces face each other.

Specific configurations of these first and second condenser lenses are shown below. Here, f is the focal length of the whole (the entire illumination optical system) (the combined focal length of the first and second condenser lenses), and FNO is the FNO of the entire illumination optical system. The FNO is (focal length of the entire illumination optical system) / {2 × (maximum height of light incident on the condenser lens)} or (focal length of the entire illumination optical system) / (second This is a value that can be calculated by the diagonal length of the fly-eye lens. r1, r2, r3, and r4 are the radii of curvature of the surface on the light source side, the surface on the liquid crystal panel side, the surface on the light source side of the second condenser lens, and the surface on the liquid crystal panel side, respectively. D1, d2, and d3 are the thickness of the first condenser lens at the optical axis position, the distance between the first condenser lens and the second condenser lens at the optical axis position, and the thickness of the second condenser lens, respectively. Show. N1 and ν1 indicate the refractive index and Abbe number of the first condenser lens, and n2 and ν2 indicate the refractive index and Abbe number of the second condenser lens. The curvature radius of ∞ (infinite) means that the surface is a plane.

(Numerical example 1)
f = 69.05 FNO = 2.0
r1 = ∞ d1 = 4.40 n1 = 1.51633 ν1 = 64.1
r2 = -100.08 d2 = 1.00
r3 = 55.38 d3 = 6.90 n2 = 1.51633 ν2 = 64.1
r4 = ∞
In FIG. 6, reference numeral 12 denotes a light exit of the polarization conversion element 6 (or an aperture stop when an aperture stop is disposed in the polarization conversion element), 13 denotes the center of the liquid crystal panel 10, and 14 denotes the liquid crystal panel 10. The end of is shown.

  By arranging the liquid crystal panel at the focal position of the condenser optical system consisting of the first and second condenser lenses 7 and 8 on the liquid crystal panel side, a parallel light beam (also referred to as a light beam from an object at infinity) is condensed on the liquid crystal panel. (Image formation). By reducing the aberration (particularly coma aberration) of this condenser optical system, the difference in the amount of light at the liquid crystal panel center (image surface center) 13 and the liquid crystal panel end portion (image surface end portion) 14 is reduced. And uniformity of illuminance on the liquid crystal panel can be improved.

  In this embodiment, the condenser optical system is composed of first and second condenser lenses having convex surfaces facing each other. By constructing a condenser optical system with two plano-convex lenses with their convex surfaces facing each other in this way, the angle of light incident on the convex surface of each lens can be reduced even off-axis. Occurrence) can be reduced. Specifically, FIG. 7 shows a lateral aberration diagram of the light beam toward the center 13 of the panel surface 10, and FIG. 8 shows a lateral aberration of the light beam incident on the peripheral portion (the end in the diagonal direction of the panel) 14 of the panel surface 10. It is a figure and the lateral aberration figure of the light ray which injects into the edge part of a panel diagonal direction is shown. As can be seen from FIGS. 7 and 8, lateral aberration (particularly coma) at the position of the liquid crystal panel is reduced, and illumination with high uniformity of illuminance on the liquid crystal panel (rectangular illumination area) can be performed. I understand. FIG. 9 shows the illuminance distribution. From FIG. 9, it can be seen that no shadows (light quantity reduction) occur at the four corners (diagonal ends) on the liquid crystal panel (illumination region).

  In addition, although the first and second condenser lenses are both plano-convex lenses with one surface being flat, the present invention is not limited to this, and a biconvex lens or a meniscus lens may be used. However, in the case of a biconvex lens, a stronger convex surface (a surface having a small radius of curvature) is considered to be replaced with the convex surface of the above-described plano-convex lens. That is, it is set as the structure which faces stronger convex surfaces. In the case of a meniscus lens, the convex surfaces are configured to face each other. For example, when one (one) of the two condenser lenses is a plano-convex lens and the other (the other) condenser lens is a meniscus lens, the convex surface of the plano-convex lens faces the convex surface of the meniscus lens. Deploy. When one of the two lenses is replaced with a biconvex lens, as described above, the stronger convex surface of the biconvex lens is arranged so as to face the positive power surface of the other lens. To do. However, it is preferable to use a plano-convex lens because it is easy to manufacture and can increase accuracy and is advantageous in terms of cost. Of the two condenser lenses, the condenser lens on the light source side is preferably a plano-convex lens.

  In the first embodiment described above, it is described that all the minute lenses constituting the first and second fly-eye lenses are decentered, but this is not restrictive. For example, when a minute lens is arranged at the center position on the x-axis of the first fly-eye lens (when a minute lens arranged at the position of the optical axis O is present among the minute lenses of the first fly-eye lens). The micro lens is configured not to be decentered. That is, in the first fly-eye lens, the microlens arranged on the positive (right side in FIG. 3) side in the x-axis direction with respect to the center of the first fly-eye lens has the optical axis of the microlens It is eccentric to the plus side with respect to the center of the outer frame of the micro lens. Conversely, in the first fly-eye lens, the minute lens arranged on the minus (left side in FIG. 3) side in the x-axis direction with respect to the center of the first fly-eye lens is light of the minute lens. The axis is eccentric to the minus side with respect to the center of the outer frame of the microlens. However, with respect to the y-axis direction, any minute lens of the first fly-eye lens is configured not to be decentered. The same can be said for the second fly-eye lens if the x-axis direction and the y-axis direction for the first fly-eye lens described above are reversed.

  In the first embodiment, the microlenses in the first and second fly-eye lenses are not arranged at the center position (the microlenses of even columns × even rows are arranged in both the x-axis direction and the y-axis direction). Therefore, all the microlenses are configured to be decentered.

  The same applies to Examples 2 and 3 described later, and it is not necessary that all the microlenses constituting the first and second fly-eye lenses are decentered, and at least a part (half or more) of the microlenses is decentered. It only has to be in mind.

  Further, instead of the above-described combination of the reflector (parabolic mirror) and the condenser lens, a reflector 53 having an elliptical reflection surface may be used as shown in FIGS. FIG. 10 is a configuration diagram in the xz section, and FIG. 11 is a configuration diagram in the yz section. As shown in the figure, the light emitted from the light source is reflected by the elliptical reflector 53 and becomes convergent light, so that the optical action is the same as that of the above-described configuration. At this time, since the condensing lens 3 becomes unnecessary, the number of parts can be reduced, and the entire configuration can be simplified. Note that the modification using the elliptical reflector is also applicable to the following second and third embodiments.

(Example 2)
12 and 13 are configuration diagrams of the second embodiment of the present invention. 22 is an optical axis of the illumination optical system, 23 is a light source, 24 is a reflector, 25 is a condenser lens, 26 is a first fly-eye lens, 27 is a second fly-eye lens, and 28 is a polarization conversion element. Then, the light whose polarization direction is aligned by the polarization conversion element enters the liquid crystal panel (image display element) 32 through the first condenser lens 29, the second condenser lens 30, and the polarization separation prism 31. The x-, y-, and z-axis directions in the figure are the same as in the first embodiment. 12 is a configuration diagram in the xz section, and FIG. 13 is a configuration diagram in the yz section. The configuration other than the condenser lens is the same as that of the first embodiment. The condenser lens is characterized in that it is composed of two lenses (meniscus lenses) having positive refractive power. The two positive lenses (positive meniscus lenses) are arranged so that their convex surfaces face each other. The reference numerals described in Numerical Example 2 described below are the same as those in Numerical Example 1.

(Numerical example 2)
f = 69.05 FNO = 2.0
r1 = -1245.05 d1 = 4.40 n1 = 1.51633 ν1 = 64.1
r2 = -95.76 d2 = 0.50
r3 = 52.92 d3 = 6.90 n2 = 1.51633 ν2 = 64.1
r4 = 692.93
In FIG. 14, reference numeral 12 denotes a light exit of the polarization conversion element 28 (or an aperture stop when an aperture stop is disposed in the polarization conversion element), 33 denotes the center of the liquid crystal panel 32, and 34 denotes the liquid crystal panel 32. The end is shown.

  If the convex surfaces of the two meniscus lenses face each other and the concave surface faces outward in this way, the incidence angle of the light incident on the lens surface can be reduced even off-axis, thereby reducing aberrations. Can do. In other words, when the two meniscus lenses are configured so that their strong convex surfaces (surfaces having a strong positive refractive power) face each other, the above-described effects can be obtained.

  FIG. 15 is a lateral aberration diagram of the light beam toward the center 33 of the panel 32, and FIG. 16 is a lateral aberration diagram of the peripheral portion 34 of the panel 32. The lateral aberration diagram of the light beam incident on the end portion in the diagonal direction of the panel. It is. As shown in these figures, the occurrence of coma aberration is reduced both on-axis and off-axis. As a result, the illumination area can have a rectangular shape with no shadows at the four corners, so that the light from the light source can be efficiently guided to the panel surface 32.

(Example 3)
17 and 18 are configuration diagrams of the third embodiment of the present invention. 35 is an optical axis of the illumination optical system, 36 is a light source, 37 is a reflector, 38 is a condenser lens, 39 is a first fly-eye lens, 40 is a second fly-eye lens, and 41 is a polarization conversion element. The light whose polarization direction is aligned by the polarization conversion element 41 enters the liquid crystal panel (image display element) 45 through the first condenser lens 42, the second condenser lens 43, and the polarization separation prism 44. The x-, y-, and z-axis directions in the figure are the same as in the first embodiment. FIG. 17 is a configuration diagram in the xz section, and FIG. 18 is a configuration diagram in the yz section. The configuration other than the condenser lens is the same as that of the first embodiment.

  The condenser lens of Example 3 is composed of two lenses (positive lenses) having positive refracting power, and the first condenser lens 42 has a flat surface on one side and a convex surface on the other side. The condenser lens 43 is convex on both sides. The first condenser lens 42 is arranged with the convex surface facing the second condenser lens side, and the second condenser lens 43 has the surface with the stronger positive refractive power facing the first condenser lens 42 side. Are arranged. That is, the first and second condenser lenses (two positive lenses) are configured such that surfaces having strong positive refractive power face each other.

(Numerical Example 3)
f = 69.05 FNO = 2.0
R1 = ∞ D1 = 4.40 N1 = 1.51633 ν1 = 64.1
R2 = -101.26 D2 = 0.50
R3 = 56.84 D3 = 6.90 N2 = 1.51633 ν2 = 64.1
R4 = -1757.36
In FIG. 19, reference numeral 12 denotes a light exit of the polarization conversion element 41 (or an aperture stop in the case where an aperture stop is disposed in the polarization conversion element), 51 denotes the center of the liquid crystal panel 45, and 52 denotes the liquid crystal panel 45. The end is shown.

  As described above, the convex surfaces of the two positive lenses face each other (the surfaces having strong positive refractive power face each other), and the second condenser lens is a biconvex lens. With this configuration, the incident angle of the light beam incident on each lens surface can be reduced even off-axis, so that the amount of aberration can be reduced.

  FIG. 20 is a lateral aberration diagram of light rays toward the center 51 of the panel 45, and FIG. 21 is a lateral aberration diagram of light rays toward the peripheral portion 52 of the panel 45 (light rays incident on the end portion in the diagonal direction of the panel). As shown in these figures, the occurrence of coma aberration is reduced both on-axis and off-axis. As a result, the illumination area can have a rectangular shape with no shadows at the four corners, so that light from the light source can be efficiently guided to the panel 45.

  In addition, you may combine the said Example 1, 2, 3 suitably. That is, the present invention is not limited to the first, second, and third embodiments as long as the first and second condenser lenses are configured so that the surfaces having strong positive refractive power face each other. For example, both the first and second condenser lenses may be biconvex positive lenses, or a combination of a biconvex lens and a meniscus lens.

Here, desirable conditions for the first and second condenser lenses are described. The curvature radius of the surface of the first and second condenser lenses (two positive lenses) constituting the condenser system on the side having a strong positive refractive power (convex surface having a small curvature radius) is weak (R1). Let R2 be the radius of curvature of the surface on the side where the positive refractive power is weak or the negative refractive power is strong. At this time,
│R1 / R2│ <0.5 (1)
It is desirable to satisfy this relationship.

  By satisfying this conditional expression (1) after disposing the two condenser lenses with the positive refractive power surfaces facing each other, the off-axis aberration can be reduced.

  Here, the values of conditional expression (1) are shown for the first and second condenser lenses of Examples 1, 2, and 3.

More preferably,
│R1 / R2│ <0.2 ... (1a)
It is desirable to satisfy

Furthermore,
│R1 / R2│ <0.1 ... (1b)
It is still desirable to satisfy

Of these two condenser lenses (positive lenses), the refractive power (optical power, reciprocal of focal length) of the positive lens arranged on the light source side is φ1, and the positive lens arranged on the illuminated surface side is Let the refractive power of the lens (optical power, reciprocal of focal length) be φ2. At this time,
0.4 <φ1 / φ2 <2.0 (2)
It is desirable to satisfy

  By satisfying this conditional expression (2), the difference in the amount (angle) of light refracted by each of the two lenses can be reduced, so that the occurrence of aberration can be reduced.

  Here, the value of conditional expression (2) of Examples 1, 2, and 3 is shown.

More preferably,
0.4 <φ1 / φ2 <0.8 (2a)
It is desirable to satisfy

Furthermore,
0.48 <φ1 / φ2 <0.7 (2b)
It is still desirable to satisfy

  In this embodiment, the illumination optical system that illuminates the liquid crystal panel (image display element, image forming element) mainly using the light beam from the light source is described, but the present invention is not limited to this. For example, the image display element described above, an illumination optical system that illuminates the image display element, and a projection optical system that projects (images project) an image formed on the image display element onto a screen (on a projection surface) It can also be applied to an image projection apparatus (projector) equipped with

The block diagram of xz section of 1st Example of this invention Configuration diagram of yz section of the first embodiment of the present invention The perspective view of the 1st fly eye lens of the 1st example of the present invention. The perspective view of the 2nd fly eye lens of the 1st example of the present invention. Optical action explanatory diagram of the first fly-eye lens of the first embodiment of the present invention Optical path diagram for aberration evaluation of condenser lens of first embodiment of the present invention Axial lateral aberration diagram of the first embodiment of the present invention Off-axis lateral aberration diagram of the first embodiment of the present invention Illustrated lighting area Configuration diagram of xz section in another configuration of the first embodiment of the present invention Configuration diagram of yz section in another configuration of the first embodiment of the present invention Configuration diagram of xz section of second embodiment of the present invention Configuration diagram of yz section of second embodiment of the present invention Optical path diagram for aberration evaluation of condenser lens of second embodiment of the present invention Axial lateral aberration diagram of the second embodiment of the present invention Off-axis lateral aberration diagram of the second embodiment of the present invention Configuration diagram of xz cross section of third embodiment of the present invention Configuration diagram of yz section of the third embodiment of the present invention Optical path diagram for aberration evaluation of condenser lens of third embodiment of the present invention Axial lateral aberration diagram of the third embodiment of the present invention Off-axis lateral aberration diagram of the third embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 0 Optical axis of illumination optical system 1 Light source 2 Reflector 3 Condensing lens 4 1st fly eye lens 5 2nd fly eye lens 6 Polarization conversion element 7 1st condenser lens 8 2nd condenser lens 9 Polarization separation prism 10 LCD panel

Claims (12)

A condensing optical system that converts a light beam emitted from a light source into a convergent light beam;
A first lens array for dividing the convergent light beam into a plurality of light beams;
A condenser optical system that includes two positive lenses and superimposes the plurality of light beams on an illuminated surface;
An illumination optical system comprising:
The two positive lenses are arranged such that the surfaces with the positive positive refractive power face each other,
Of the two positive lenses, when the refractive power of the positive lens arranged on the light source side is φ1, and the refractive power of the positive lens arranged on the illuminated surface side is φ2,
0.4 <φ1 / φ2 <0.8
An illumination optical system characterized by satisfying the following relationship.   The illumination optical system according to claim 1, wherein the condenser optical system includes the two positive lenses. The illumination optical system according to claim 1 or 2 , wherein one of the two positive lenses has a flat surface and the other surface has a convex surface. The illumination optical system according to claim 1 or 2 , wherein one of the two positive lenses has a concave surface and the other surface has a convex surface. Wherein one of the two positive lenses is convex on both sides, the illumination optical system according to claim 1 or 2 other, wherein at least one surface is convex. The condensing optical system includes a parabolic reflector that reflects a light beam from the light source, and
The illumination optical system according to any one of claims 1 to 5 , further comprising a positive lens that collects the light beam reflected by the paraboloidal reflector. The light converging optical system, an illumination optical system according to any one of claims 1 to 5, characterized in that an elliptical reflector for reflecting the light beam from the light source. The illumination optical system according to any one of claims 1 to 7 to the condenser optical system, are substantially parallel light beam, wherein the incident. When a cross section that includes the optical axis of the illumination optical system and is orthogonal to each other is a first plane and a second plane,
The illumination according to any one of claims 1 to 8 , wherein the first lens array converts a convergent light beam from the condensing optical system into a substantially parallel light beam on the second plane. Optical system. A second lens array for guiding the plurality of light beams emitted from the first lens array to the condenser optical system;
The illumination optical system according to claim 9 , wherein the second lens array converts a convergent light beam from the condensing optical system into a substantially parallel light beam in the first plane. A second lens array for guiding the plurality of light beams emitted from the first lens array to the condenser optical system;
The surface to be illuminated is, illumination optical system according the any one of claims 1 to 10, characterized in that it is disposed at the focal position of the illumination surface side of the condenser optical system. An image display element;
The illumination optical system according to any one of claims 1 to 11, wherein the image display element is illuminated with a light beam from a light source.
An image projection apparatus comprising: a projection optical system that projects a light beam emitted from the image display element onto a projection surface.

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