JP2001133883A - Illumination system and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination system for a projector efficiently separating incident light and reflected light even when the luminous flux angle of the incident light or a light source image with respect to a color wheel is large. SOLUTION: The illumination system for a projector is constituted of a lamp LA emitting illuminating light, a reflection type color wheel(CW) reflecting the illuminating light so that the color of the reflected light is temporally successively switched, and a deflection prism PR deflecting the illuminating light by reflection on a total reflection surface S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination system and a projector using the same, and more particularly, to an illumination system having a reflection type color wheel for colorizing a projected image, and an illumination system using the same. And a projector that projects a color image.

[0002]

2. Description of the Related Art When a reflection type color wheel is used as a color separation system in an illumination system for a projector, it is necessary to separate incident light and outgoing light (that is, reflected light) from the color wheel. FIG. 11 shows a general color separation configuration for performing the separation spatially. In the figure, the thick line is incident light, and the thin line is reflected light. The color wheel (CW) that reflects the incident light is composed of a plurality of (R, G, B, etc.) color filters having different reflected light colors, and the color light illuminating the display element (not shown) is temporally sequential. It is configured to be rotatable (ax: rotation axis) by a motor or the like so as to be switched.

[0003]

As shown in FIG.
If the incident light is converged at one point using an ideal point light source,
The incident light and the reflected light can be spatially separated at a large angle. However, in practice, the light source image has a certain size as shown in FIG. 12, so that the incident light and the reflected light overlap. Since it is impossible to separate the incident light and the reflected light in the part where the light rays overlap, the light rays will be lost or the luminous flux angle will be reduced in advance so that the light rays do not overlap (for example, the focal length of the condenser lens). To make the light flux thinner). However, when the luminous flux angle is reduced, the light source image becomes larger, which is disadvantageous in improving the loss of the light beam, the efficiency of transmitting light to the display element is reduced, and the size of the illumination system is increased.

[0004] Further, as shown in FIG.
(MR), even when the incident light and the reflected light are separated angularly, the light indicated by the broken line is reflected by the mirror (M
R) causes vignetting, which also results in light ray loss. As described above, in the conventional method, when a reflection type color wheel is used as the color separation system of the illumination system, there is a problem that light loss cannot be avoided, and thus a bright projected image cannot be obtained.

The present invention has been made in view of such a situation, and an object of the present invention is to efficiently separate incident light and reflected light even if the light beam angle of the incident light with respect to the color wheel and the light source image are large. An object of the present invention is to provide a lighting system for a projector that is frequently performed, and to provide a projector that can obtain a bright projected image using the lighting system.

[0006]

To achieve the above object, a lighting system according to a first aspect of the present invention comprises a lamp for emitting illumination light and a reflection for reflecting illumination light such that the color of reflected light is sequentially switched over time. An illumination system for a projector, comprising: a color wheel of a mold; and a deflecting member for deflecting illumination light, wherein the deflecting member has a total reflection surface for reflecting the illumination light.

A lighting system according to a second aspect of the present invention is a lamp that emits illumination light, a reflection-type color wheel that reflects illumination light so that the color of reflected light is sequentially changed over time, and a deflection member that deflects the illumination light. A lighting system for a projector, comprising: a first deflecting surface on which the deflecting member deflects illumination light before being incident on the color wheel; and an illumination system for illuminating light after being reflected by the color wheel. And a second deflecting surface for deflecting, wherein at least one of the first and second deflecting surfaces is a total reflection surface for reflecting illumination light.

According to a third aspect of the present invention, in the illumination system according to the first or second aspect, the lamp reflects illumination light from the light source on a rotationally symmetric reflection curved surface with a light source emitting illumination light. It is characterized by having a primary mirror and a secondary mirror that reflects a part of the illumination light reflected by the primary mirror and returns it to the position of the light source.

A projector according to a fourth aspect of the present invention is the projector of the second aspect,
Or, a projector comprising: a lighting system according to the third aspect of the invention, a display element for modulating illumination light from the lighting system, and a projection optical system for projecting an image with light modulated by the display element, The optical axis of the projection optical system is substantially perpendicular to the rotation axis of the color wheel.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a lighting system and a projector embodying the present invention will be described with reference to the drawings.
In the above-described conventional examples (FIGS. 11 to 13), the embodiments, and the like, the same or corresponding portions are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

FIG. 2 shows a lighting system according to the first embodiment. This lighting system consists of a lamp (L
A), a reflection type color wheel (CW) that reflects the illumination light so that the reflected light color is sequentially switched in time, and a deflection prism (PR) that deflects the illumination light, a lighting system for a projector. It is. The deflecting prism (PR) has a total reflection surface (S) that reflects the illumination light, and the illumination light emitted from the lamp (LA) passes through the total reflection surface (S) and passes through the deflection prism (PR). ). Illumination light incident on the deflection prism (PR), after once exiting from the deflection prism (PR),
By being reflected by the color wheel (CW), the color of the reflected light is sequentially switched in time. Color wheel (C
The illumination light reflected by W) again enters the deflecting prism (PR), is totally reflected by the total reflection surface (S), and then exits the deflecting prism (PR).

As described above, when a reflection type color wheel (CW) is used as a color separation system in a lighting system for a projector, it is necessary to separate incident light and reflected light from the color wheel (CW). In the first embodiment, a configuration is adopted in which a deflecting prism (PR) having a total reflection surface (S) is used to perform angular separation using a deflecting prism (PR). If a deflecting member having a total reflection surface (S) is used to separate incident light and reflected light from the reflection type color wheel (CW), the separation is performed by selecting an angle. For this reason, the color wheel (CW)
Even if the luminous flux angle of the incident light and the light source image are large as shown in FIG. 1, it is possible to efficiently separate the incident light and the reflected light. In other words, even if the light source image is large, there is no light loss due to the overlap of the incident light and the reflected light, and there is no need to reduce the luminous flux angle. Therefore, if this illumination system is used for a projector, a bright projected image can be obtained.

In the first embodiment (FIGS. 1 and 2), the total reflection is performed on the light reflected by the color wheel (CW). On the other hand, the second to seventh embodiments described below will be described. In the embodiments (FIGS. 3 to 10), total reflection is performed on the light incident on the color wheel (CW). In the second to seventh embodiments, the reflecting surfaces (S1, S2) are arranged on the incident side and the reflecting side with respect to the color wheel (CW), respectively. By using two reflecting surfaces (S1, S2) as deflecting surfaces for deflecting the illumination light, the lamp (LA) side and the display element {DMD (Digital Micromirror Device) (3) in FIGS. Equivalent to. The degree of freedom of arrangement with the} side is improved. If the degree of freedom in arrangement is improved, it is possible to achieve a thin and space-saving lighting system, so that a thin and compact mobile-type projector demanded in the market can be realized.

In the second to seventh embodiments, the first reflecting surface (S1) is a total reflecting surface, but the first and second reflecting surfaces (S1)
If at least one of the surfaces (1, S2) is a total reflection surface that reflects illumination light, incident light and reflected light can be separated with high efficiency as in the first embodiment. Since the deflecting surface that is not the total reflection surface does not necessarily need to be a reflection surface, the same applies if an optical surface having a deflecting action, such as a refraction surface or a diffraction surface, is used instead of the second reflection surface (S2). It is possible to realize the function.

FIG. 3 shows a lighting system according to a second embodiment. FIG. 3A is a top view, and FIG. 3B is a front view. This lighting system is a lamp (LA) that emits illumination light
, A reflective color wheel (CW), first and second deflecting prisms (PrA, PrB) for deflecting illumination light, and a relay optical system
(RL). The deflecting prisms (PrA, PrB) reflect the illumination light after being reflected by the color wheel (CW) and the first reflection surface (S1) that reflects the illumination light before entering the color wheel (CW). And a second reflection surface (S2) to be used, of which the first reflection surface (S1) is a total reflection surface for reflecting illumination light. That is, the first deflection prism (PrA) and the second deflection prism (PrB)
Thus, a so-called TIR (Total Internal Reflection) prism is formed.

The illumination light emitted from the lamp (LA) first enters the first deflecting prism (PrA). The first deflecting prism (PrA) is composed of a right-angle prism that satisfies the condition of total reflection on the first reflecting surface (S1), and the illumination light incident thereon is reflected by the color wheel (CW) on the first reflecting surface (S1). It is totally reflected toward. The illumination light totally reflected by the first reflecting surface (S1) is once emitted from the first deflecting prism (PrA), and then is emitted from the color wheel (CW).
, The reflected light color is sequentially switched in time. The illumination light reflected by the color wheel (CW) is incident again on the first deflecting prism (PrA), and is reflected on the first reflecting surface.
(S1) is transmitted. Then, the surface opposing the first reflection surface (S1) {the opposing surfaces of the first and second deflecting prisms (PrA, PrB) are located substantially parallel with a predetermined air gap. }, And enter the second deflecting prism (PrB). The illumination light incident on the second deflecting prism (PrB) is reflected by the second reflecting surface (S2), exits the second deflecting prism (PrB), and passes through the relay optical system (RL). The second reflection surface (S2) is a mirror surface on which metal deposition is performed, but may be a total reflection surface.

FIG. 4 shows a lighting system according to a third embodiment. FIG. 4A is a top view, and FIG. 4B is a front view. This lighting system is a lamp (LA) that emits illumination light
A reflection type color wheel (CW), a first deflecting prism (PrA) for deflecting the illumination light, and an integrator rod (IR) for deflecting the illumination light and making its spatial energy distribution uniform. And a relay optical system (RL). The feature of this embodiment is that an integrator rod (IR) having a second reflecting surface (S2)
Is used as the second deflecting member. However, the second
The deflection on the reflecting surface (S2) is performed in the same manner as in the second embodiment.

The incident end face of the integrator rod (IR)
It is located substantially parallel to the first reflecting surface (S1) of the opposing first deflecting prism (PrA) with a predetermined air gap. The illumination light incident from the entrance end face is first reflected on the second reflection surface (S
Reflected in 2). An integrator rod (IR) is a polygonal glass body or a hollow cylindrical body formed by combining a plurality of mirrors. Therefore, the illumination light that has entered the integrator rod (IR) at various angles is reflected on the side surface of the integrator rod (IR) many times after being reflected on the second reflecting surface (S2), and thus, the spatial light is reflected. Energy distribution (that is, illuminance distribution) is made uniform. Then, the light is emitted as diffused light from an emission end face conjugate with a display surface of a display element (not shown), and then passes through a relay optical system (RL).

Fourth to seventh embodiments described below
(FIGS. 5 to 8) relate to the arrangement of lamps (LA) for reducing the thickness of the lighting system. The lamp (LA) includes a light source (LS) that emits illumination light, and a reflector including a primary mirror and a secondary mirror.The primary mirror reflects the illumination light from the light source (LS) on a rotationally symmetric reflection curved surface, The sub-mirror reflects a part of the illumination light reflected by the primary mirror and returns it to the position of the light source (LS). In the illumination systems of the fourth and fifth embodiments, the primary mirror is a parabolic mirror (M1), and the secondary mirror is a plane mirror (m1). In the illumination systems of the sixth and seventh embodiments, the primary mirror is an ellipsoidal mirror (M2) and the secondary mirror is a spherical mirror (m
2).

FIG. 5 shows a lighting system according to a fourth embodiment. FIG. 5A is a top view, and FIG. 5B is a front view. This lighting system is a lamp (LA) that emits illumination light
And a condenser lens (CL) that collects illumination light from the lamp (LA), a reflective color wheel (CW), and first and second deflecting prisms (PrA, PrB) that deflect illumination light. And a relay optical system (RL). The feature of this embodiment is that the reflector of the lamp (LA) is a parabolic mirror (M1) that reflects the illumination light from the light source (LS) on a paraboloid, and the parabolic mirror (M1) reflects the light. Plane mirror (m) that reflects a part of the
1). According to this configuration,
Even if the lamp optical axis (AX0) is parallel to the reflection surface of the color wheel (CW), it is possible to satisfy the condition for total reflection on the first reflection surface (S1). Therefore, it is possible to achieve a high-efficiency separation of incident and reflected light and to achieve a reduction in the thickness of the illumination system.

Since the light source (LS) is located at the focal position of the parabolic mirror (M1), the illumination light emitted from the light source (LS) is transmitted to the parabolic mirror (M1).
Becomes substantially parallel to the lamp optical axis (AX0) due to reflection from the lamp. Lower half of aperture of parabolic mirror (M1) {color wheel (CW)
Is covered with a plane mirror (m1) having a reflection surface perpendicular to the lamp optical axis (AX0). For this reason, parabolic mirrors
After being reflected by the plane mirror (m1), the illumination light reflected by the lower half of (M1) returns to the light source (LS) position through the original optical path. Then, the light is emitted from the upper half of the opening together with the illumination light reflected by the upper half of the parabolic mirror (M1). The illumination light emitted from the parabolic mirror (M1) passes through a D-cut condenser lens (CL), and then enters a first deflecting prism (PrA). The illumination light after entering the first deflecting prism (PrA)
The relay optical system (RL) is emitted by receiving the same optical action as in the second embodiment (FIG. 3). In addition, condenser lens
(CL) is D-cut because the lower half covered with the plane mirror (m1) is unnecessary, but it may of course be a general circular shape.

FIG. 6 shows a lighting system according to a fifth embodiment. FIG. 5A is a top view, and FIG. 5B is a front view. This lighting system consists of a parabolic mirror (M1) and a plane mirror (m1)
A lamp (LA) having a reflector consisting of
Condenser lens (CL) that collects illumination light from A),
A reflective color wheel (CW), a first deflecting prism (PrA) for deflecting the illumination light, and an integrator rod for deflecting the illumination light and making its spatial energy distribution uniform
(IR) and a relay optical system (RL) for a projector. The feature of this embodiment is that, similarly to the third embodiment (FIG. 4), an integrator rod (IR) having a second reflecting surface (S2) is used as a second deflecting member. The configuration is the same as that of the fourth embodiment (FIG. 5).

FIG. 7 shows a lighting system according to a sixth embodiment. FIG. 7A is a top view, and FIG. 7B is a front view. This lighting system is a lamp (LA) that emits illumination light
And a condenser lens (CL) that collects illumination light from the lamp (LA), a reflective color wheel (CW), and first and second deflecting prisms (PrA, PrB) that deflect illumination light. And a relay optical system (RL). The feature of this embodiment is that the reflector of the lamp (LA) is an ellipsoidal mirror (M2) that reflects the illumination light from the light source (LS) on an elliptical surface, and the illumination reflected by the ellipsoidal mirror (M2). A spherical mirror (m) that reflects part of the light and returns it to the position of the light source (LS)
2). According to this configuration,
Even if the lamp optical axis (AX0) is parallel to the reflection surface of the color wheel (CW), it is possible to satisfy the condition for total reflection on the first reflection surface (S1). Therefore, it is possible to achieve a high-efficiency separation of incident and reflected light and to achieve a reduction in the thickness of the illumination system.

Since the light source (LS) is at the first focal position of the ellipsoidal mirror (M2), the illumination light emitted from the light source (LS) is
An image is formed at the second focal position by the reflection at (M2). The spherical mirror (m2) has a convex reflecting surface composed of a part of a spherical surface centered on the second focal point of the elliptical mirror (M2), and has a substantially lower half {color Back side of wheel (CW)}
Is covered with a spherical mirror (m2). For this reason, an ellipsoidal mirror (M
2) The illumination light reflected by the lower half returns to the light source (LS) position through the original optical path after being reflected by the spherical mirror (m2). Then, the light is emitted from the upper half of the aperture together with the illumination light reflected by the upper half of the ellipsoidal mirror (M2). The illumination light emitted from the ellipsoidal mirror (M2) enters the first deflecting prism (PrA). The illumination light after entering the first deflecting prism (PrA)
The relay optical system (RL) is emitted by receiving the same optical action as in the second embodiment (FIG. 3).

FIG. 8 shows a lighting system according to a seventh embodiment. FIG. 8A is a top view, and FIG. 8B is a front view. This illumination system has an elliptical mirror (M2) and a spherical mirror (m2)
(LA) having a reflector consisting of: a reflective color wheel (CW); a first deflecting prism (PrA) for deflecting illumination light; and deflecting illumination light and making its spatial energy distribution uniform. Integrator rod (IR)
And a relay optical system (RL). The features of this embodiment are the third and fifth features.
As in the second embodiment (FIGS. 4 and 6), an integrator rod (IR) having a second reflecting surface (S2) is used as a second deflecting member. It has the same configuration as (FIG. 7).

Next, a lighting system according to a third embodiment will be described.
A projector to which (FIG. 4) is applied will be described with reference to FIGS. FIG. 9 is a front view of the projector viewed from the back side of the DMD (3), and FIG. 10 is a top view of the projector viewed from above. In the figure, AX1 is an illumination optical axis, and AX2 is a projection optical axis. This projector includes an illumination system, a DMD (3) that modulates illumination light from the illumination system, and a projection optical system (4) that performs image projection with light modulated by the DMD (3) that is a display element. have. The illumination system includes a lamp (LA), a reflective color wheel (CW), a first deflecting prism (PrA), an integrator rod (IR), and first to third relay lenses (RL1).
RL3), deflection prism (1), and TIR prism (2). Note that the first to third relay lenses (RL1 to RL
3) corresponds to the relay optical system (RL).

The illumination light emitted from the lamp (LA) is
After being incident on the deflecting prism (PrA) and reflected by the first reflecting surface (S1), it is reflected by the color wheel (CW). The color wheel (CW) is composed of a plurality of (R, G, B, etc.) color filters with different reflected light colors, and is driven by a motor or the like so that the color light illuminating the DMD (3) is sequentially switched in time. It is configured to be rotatable (ax: rotation axis). Color wheel
The illumination light reflected by (CW) is reflected by the integrator rod (IR)
And is reflected by the second reflecting surface (S2). Then, by passing through the integrator rod (IR), the spatial energy distribution is made uniform. By making the energy distribution uniform, there is no difference in illuminance between the on-axis and off-axis positions on the display surface of the DMD (3).

The illumination light emitted from the integrator rod (IR) passes through the first and second relay lenses (RL1 and RL2), and then enters the square prism-shaped deflection prism (1). The illumination light incident on the deflection prism (1) is totally reflected by the reflection surface (RT), then is mirror-reflected by the reflection surface (RM), and further reflected by the reflection surface (RT).
And exits the deflection prism (1). That is, the illumination light path is bent obliquely upward at an obtuse angle by the two reflection surfaces (RT, RM) inside the deflection prism (1).

The illumination light whose optical path is bent by the deflection prism (1) passes through a third relay lens (RL3), and
The angle is converted in the R prism (2). TIR prism (2)
Is composed of a first prism (2a) and a second prism (2b). The TIR prism (2) separates the input light and the output light from the DMD (3). 1st prism
Since the third relay lens (RL3) is joined to (2a), the illumination light that has passed through the third relay lens (RL3) directly enters the first prism (2a). Illumination light incident on the first prism (2a) is reflected by a reflection surface {facing the second prism (2b) {the opposing surfaces of the first and second prisms (2a, 2b) are separated by a predetermined air gap. They are located substantially parallel. }
The DMD (3) is illuminated from an oblique 45 ° direction. Then, the illumination light is optically modulated by reflection at the DMD (3).

The DMD (3) has a display surface on which a large number of micromirrors are arranged in a matrix, and one micromirror constitutes one pixel of a display image. The tilt of each micromirror is controlled individually for light modulation, and each micromirror is turned on.
Two inclination states, a state and an OFF state, can be taken. The micromirror in the ON state reflects illumination light toward the inside of the projection optical system (4), and the micromirror in the OFF state reflects illumination light outside the projection optical system (4). Therefore, the light reflected by the ON state micromirror is
After passing through the TIR prism (2) in the order of the first and second prisms (2a, 2b), the light enters the projection optical system (4) and reaches a projection surface (for example, a screen surface). As a result, a display image including a light and dark pattern is formed on the projection surface.

The illumination light path before incidence on the TIR prism (2) is
As described above, since the beam is bent at an obtuse angle by the deflection prism (1), restrictions on the arrangement of the relay lenses (RL1, RL2) and the like are relaxed. Therefore, the height of the projector is reduced in a state where the lamps (LA) are horizontally arranged, and the projector is easily made thin and compact. The deflection prism (1) has one total reflection surface (RT) and one mirror reflection surface (RM), and the reflection surface (RT) that performs total reflection is also used as an emission surface that is a transmission surface. Has become. When the deflection prism (1) that performs total reflection and mirror reflection inside is used as described above, the illumination light paths are overlapped in the deflection prism (1), so that the optical path length is compressed. As a result, a compact optical system has been achieved,
Also, there is no need to use a large reflecting surface.

As can be seen from FIGS. 9 and 10, the optical axis (AX2) of the projection optical system (4) and the rotation axis of the color wheel (CW).
It is almost perpendicular to (ax). If the rotation axis (ax) of the color wheel (CW) is substantially perpendicular to the projection optical axis (AX2), since the color wheel (CW) does not protrude up and down,
Even if the color wheel (CW) is large, the overall thickness of the projector can be reduced.

[0033]

As described above, according to the illumination system of the present invention, since the deflecting member for reflecting the illumination light on the total reflection surface is used, the luminous flux angle of the incident light with respect to the color wheel and the light source image are large. However, it is possible to efficiently separate incident light and reflected light. Therefore, according to the projector of the present invention, a bright projected image can be obtained.

[Brief description of the drawings]

FIG. 1 is an optical path diagram for explaining an optical function of a deflecting prism according to a first embodiment.

FIG. 2 is an optical configuration diagram showing the illumination system according to the first embodiment.

FIG. 3 is an optical configuration diagram showing an illumination system according to a second embodiment.

FIG. 4 is an optical configuration diagram showing an illumination system according to a third embodiment.

FIG. 5 is an optical configuration diagram showing an illumination system according to a fourth embodiment.

FIG. 6 is an optical configuration diagram showing an illumination system according to a fifth embodiment.

FIG. 7 is an optical configuration diagram showing an illumination system according to a sixth embodiment.

FIG. 8 is an optical configuration diagram showing an illumination system according to a seventh embodiment.

FIG. 9 is a front view showing an optical configuration of a projector according to a third embodiment.

FIG. 10 is a top view illustrating an optical configuration of a projector according to a third embodiment.

FIG. 11 is an optical path diagram for explaining an illumination system when an ideal point light source forms an image on a color wheel.

FIG. 12 is an optical path diagram for explaining an illumination system when an actual light source forms an image on a color wheel.

FIG. 13 is an optical path diagram for explaining an illumination system in which incident light and reflected light are angularly separated by a mirror.

[Explanation of symbols]

 LA: Lamp PR: Deflection prism (deflection member) S: Total reflection surface CW: Color wheel ax: Rotation axis PrA: First deflection prism (deflection member) PrB: Second deflection prism (deflection member) S1: First reflection surface (First deflecting surface, total reflecting surface) S2… second reflecting surface (second deflecting surface) RL… relay optical system IR… integrator rod (deflecting member) CL… condenser lens LS… light source M1… parabolic mirror (main Mirror) m1 ... Plane mirror (secondary mirror) M2 ... Elliptical mirror (primary mirror) m2 ... Spherical mirror (secondary mirror) RL1 ... First relay lens RL2 ... Second relay lens RL3 ... Third relay lens 1 ... Deflection prism RT ... Reflection surface RM Reflection surface 2 TIR prism 2a First prism 2b Second prism 3 DMD (display element) 4 Projection optical system AX0 Lamp optical axis AX1 Illumination optical axis AX2 Projection optical axis (Optical axis of the system)

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Claims (4)

[Claims] 1. A lamp that emits illumination light, a reflection type color wheel that reflects illumination light so that a reflected light color is sequentially switched over time, and a deflecting member that deflects illumination light.
An illumination system for a projector, comprising: a deflecting member having a total reflection surface that reflects illumination light. 2. A lamp that emits illumination light, a reflection-type color wheel that reflects illumination light so that a reflected light color is sequentially switched over time, a deflection member that deflects illumination light,
An illumination system for a projector, comprising: a first deflecting surface that deflects illumination light before being incident on the color wheel; and deflects illumination light after being reflected by the color wheel. A second deflecting surface to be performed, and at least one of the first and second deflecting surfaces is
An illumination system, which is a total reflection surface that reflects illumination light. 3. The light source, wherein the lamp emits illumination light.
A main mirror that reflects illumination light from the light source on a rotationally symmetric reflection curved surface, and a sub-mirror that reflects a part of the illumination light reflected by the main mirror and returns the light source to the position of the light source. The lighting system according to claim 1 or 2, wherein 4. A lighting system according to claim 2 or 3, a display element for modulating illumination light from the lighting system, and a projection optical system for projecting an image with light modulated by the display element. The projector according to claim 1, wherein an optical axis of the projection optical system and a rotation axis of the color wheel are substantially perpendicular to each other.