JP2011113002A - Lighting apparatus and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting apparatus which can easily manufacture a lens array while increasing lighting efficiency and to provide a projector using the lighting apparatus. <P>SOLUTION: In a luminous flux adjusting device 80, a first partial luminous flux SL1 is spatially kept in a non-inversion state, a second partial luminous flux SL2 is spatially inverted, and the first and second partial luminous fluxes SL1 and SL2 are emitted in a state where polarization states are adjusted. Thus, it is unnecessary to pass through a polarization beam splitter array, after passing through lens arrays 31 and 32 for uniforming, so that lighting efficiency can be increased. Further, the lens arrays 31 and 32 eliminate requirement of eccentricity or the like, so that ones having a simple structure can be used. Since the first and second partial luminous fluxes SL1 and SL2 are inverted to each other and taken out, a lighting luminous flux reduced in deviation, in which the illuminance unevenness of the lighting luminous flux formed by a concave mirror 22b is reduced can be obtained. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an illumination device having a reflecting mirror that reflects light from an arc tube and a projector using the same.

  An illumination device for a projector, which includes a lens array and a polarization conversion element, and the polarization conversion element separates a plurality of partial light beams that have passed through the lens array into two types of polarization components, and In addition, there is known one having a phase difference plate that aligns the polarization directions of two types of polarization components emitted from a polarization beam splitter array (see Patent Document 1).

  Further, as another illumination device, an ellipsoidal reflector (reflecting mirror) is provided, and the rotationally asymmetric shape is different from each other in the shape of the vertical section and the shape of the horizontal section including the central axis of the reflector. A device that uses a reflecting surface to reduce the thickness of the device is known (see Patent Document 2).

Japanese Patent Laid-Open No. 11-183848 JP 2009-54340 A

  However, in the case of the illumination device of Patent Document 1, the light source image is doubled by the polarization beam splitter array, and the illumination efficiency is lowered. Further, in order to reduce the loss in the polarization beam splitter array, it is necessary to decenter each element lens constituting the lens array, which makes it difficult to manufacture the lens array and makes the illumination device expensive. Yes.

  In addition, when the reflective surface which has an elliptical shape from which a vertical cross section and a horizontal cross section mutually differ like the illuminating device of patent document 1, the aspect-ratio of the illumination light beam inject | emitted from an illuminating device can be adjusted freely. However, the problem that the illumination efficiency is lowered by the polarization beam splitter array and the problem that the manufacture of the eccentric lens array is not easy are not solved.

  SUMMARY An advantage of some aspects of the invention is that it provides an illumination device that can increase illumination efficiency and can easily manufacture a lens array, and a projector using the illumination device.

  In order to solve the above-described problems, an illumination device according to the present invention includes an arc tube cut by one plane among a light-emitting tube that generates light and a shape cut by two planes perpendicular to each other including the system optical axis. An anamorphic reflection having a reflection surface having a non-rotationally symmetric concave shape that is different in shape from the shape of an arc cut off on the other plane, and that emits illumination light by reflecting light from the arc tube at the reflection surface A mirror, a collimating lens arranged parallel to the light path of the arc tube and the anamorphic reflector, and a collimating lens that collimates the transmitted light; and a light collimating lens arranged downstream of the optical path of the collimating lens. Branching into a first partial light beam and a second partial light beam, maintaining the first partial light beam in a spatially non-inverted state, spatially reversing the second partial light beam, and at least one of the first and second partial light beams One polarization It converts, and a light flux adjusting device emitting in a state where the first and second partial beams of uniform polarization state.

  In the illuminating device, the light beam adjusting device maintains the first partial light beam in a spatially non-inverted state, spatially reverses the second partial light beam, and aligns the first and second partial light beams in a polarization state. Therefore, if a lens array for homogenization is provided on the downstream side of the optical path of the collimating lens, there is no need to pass through a polarizing beam splitter array that doubles the light source image after passing through this lens array, thereby improving illumination efficiency. It is possible to increase the uniformity, and uniformization can be performed using a lens array having a simple structure. Further, in the above illumination device, the first partial light beam and the second partial light beam are reversed and taken out at the time of polarization conversion in which the polarization state is aligned in advance, so that the illumination light beam formed by the reflecting mirror has uneven illuminance. In addition, it is possible to obtain an illumination light beam with less bias with reduced illuminance unevenness.

  Further, according to a specific aspect or aspect of the present invention, the light beam adjusting device includes a polarization branching member that branches the incident light into the first partial light beam of the first polarization and the second partial light beam of the second polarization, A first reflecting member for inverting the second partial light beam by bending the optical path; In this case, the optical path of the second partial light beam can be bent and guided in the same direction as the first partial light beam by the first and second reflecting members, and the continuous joining of the first and second partial light beams can be easily performed. Become.

  According to another aspect of the present invention, the first and second reflecting members are first and second prisms that respectively bend the optical path by internal reflection, and the light beam adjusting device includes the polarization branching member and the first and first prisms. It has an integrated structure in which two prisms are joined. In this case, the light flux adjusting device can be handled as an integral block-shaped component, and it is easy to incorporate and adjust the lighting device.

  According to another aspect of the present invention, the polarization branching member includes a light incident surface that receives light incident on the light flux adjusting device, a first light exit surface that emits the first partial light flux to the outside, and a second portion. A first connection surface for extracting the light beam, and the first reflecting member is connected to the first connection surface of the polarization branching member to allow the second partial light beam to pass therethrough and the second connection surface for extracting the second partial light beam. And the second reflecting member is connected to the second connection surface of the first reflecting member to allow the second partial light beam to pass therethrough and has a second light emitting surface for emitting the second partial light beam to the outside. In this case, the first partial light beam of the first polarization branched by the polarization branching member out of the light incident on the light beam adjusting device is emitted from the first light exit surface provided on the polarization branching member, and the second light of the second polarization. The partial light flux is guided from the polarization branching member to the second reflecting member through the first reflecting member, and is emitted from the second light exit surface provided on the second reflecting member.

  According to another aspect of the present invention, the first reflecting member has two reflecting surfaces, and the second partial light beam that has passed through the polarization branching member has a system optical axis that extends to the downstream side of the light path of the light beam adjusting device. The second partial light beam is inverted with respect to the direction perpendicular to the reference plane by bending twice in a direction perpendicular to the traveling direction in a plane perpendicular to the reference plane including the second reflecting member. The second partial light beam having two reflecting surfaces and bent through the first reflecting member is bent once in a direction perpendicular to the traveling direction in a plane parallel to the reference plane. In this case, on the assumption that the second partial light beam is branched in a direction parallel to the reference plane and perpendicular to the system optical axis, the second partial light beam is directed in a direction perpendicular to the reference plane by the first reflecting member. And can be emitted in the same direction as the first partial light beam by the second reflecting member.

  According to another aspect of the present invention, the light flux adjusting device has a half-wave plate on one of the first light exit surface and the second light exit surface. In this case, the polarization states of the first and second partial light beams emitted from the first and second light exit surfaces can be easily matched.

  According to another aspect of the present invention, one of the planes extends in parallel to a reference plane including a system optical axis extending downstream of the optical path of the light beam adjusting device, and on the reflection surface of the anamorphic reflector, The shape cut out in one plane draws a parabolic arc whose focal point is the center between the electrodes of the arc tube, and the shape cut out in the other plane is an elliptical shape whose focal point is the parabolic arc. Draw an arc. In this case, about one said plane, a light beam can be collimated previously by the shape which draws a parabolic arc. That is, with respect to the one plane, it is possible to configure the latter optical component used for collimating the light beam with a relatively inexpensive one. In addition, since the other plane has a shape that draws an elliptical arc, the dimension in the direction perpendicular to the system optical axis can be made relatively short to reduce the thickness of the lighting device.

  According to another aspect of the present invention, the aspect ratio of the light incident surface of the light flux adjusting device is 2: 1 or more. In this case, the light emitted from the light beam adjusting device has a square light beam cross section or a long light beam cross section in the direction of one plane.

  According to another aspect of the present invention, the arc tube has an auxiliary reflector that reflects light emitted from the center between the electrodes of the arc tube to the opposite side of the anamorphic reflector in the reverse direction. In this case, it is possible to effectively recover the light beam directly emitted to the downstream side of the optical path, and it is possible to improve the light utilization efficiency.

  According to another aspect of the present invention, the collimating lens is bonded to the light incident surface of the light flux adjusting device. In this case, the collimating lens can be easily assembled.

  According to another aspect of the present invention, the collimating lens is a cylindrical lens having a cylindrical aspherical surface. In this case, the passing light beam can be collimated by a collimating lens having a relatively simple shape.

  In order to solve the above-described problem, a projector according to the present invention projects any one of the above-described illumination devices, a light modulation device illuminated by a light beam emitted from the illumination device, and a light beam emitted from the light modulation device. A projection optical system. In this case, by using any one of the illumination devices described above, the projector as a whole can be thinned easily while maintaining the quality of illumination light.

It is a top view which shows notionally the projector incorporating the illuminating device which concerns on 1st Embodiment. (A)-(C) are the horizontal sectional view for demonstrating the branching of the light beam by the illuminating device which concerns on 1st Embodiment, a vertical sectional view, and the figure of a light beam adjusting device. (A), (B) is a figure which shows the mode of the light beam in the horizontal cross section and vertical cross section of an illuminating device. It is a perspective view which shows the reflective mirror of an illuminating device. It is a figure of the light beam cross section formed with a light source. It is a perspective view which shows the light beam adjustment apparatus of an illuminating device. (A)-(D) are the schematic diagrams for demonstrating inversion of the light beam up and down. (A), (B) is a schematic diagram for demonstrating inversion of the right and left of a light beam. It is a figure which shows the modification of an illuminating device. It is a figure which shows another modification of an illuminating device. It is a top view which shows notionally the illuminating device which concerns on 2nd Embodiment. It is a top view which shows notionally the modification of the illuminating device which concerns on 2nd Embodiment.

[First Embodiment]
Hereinafter, with reference to FIG. 1 etc., the illuminating device which concerns on 1st Embodiment of this invention, and a projector using the same are demonstrated.

  As shown in FIG. 1, a projector 100 incorporating the illumination device 10 according to the present embodiment includes, in addition to the illumination device 10, a color separation light guide unit 40, a light modulation unit 50, a color synthesis unit 60, and a projection optical system 70. Is provided.

  First, the illuminating device 10 is an illuminating optical system including the light source lamp unit 20, the light beam adjusting device 80, and the uniformizing optical system 30.

  The light source lamp unit 20 includes a lamp unit 21a and a collimating lens 21b which is a concave cylindrical lens as a light source. The lamp unit 21a includes an arc tube 22a, a concave mirror 22b, and a sub mirror 23a. Further, as shown in FIG. 2A and the like, in the light source lamp unit 20, the arc tube 22a includes a translucent quartz glass tube portion PB having a central portion bulged in a spherical shape, and a tube portion. There are first and second sealing portions 24a and 24b extending on both ends of the PB, and inside the tube portion PB sealed by the sealing portions 24a and 24b, mercury, rare gas and a small amount of halogen are contained. It is enclosed. The center between the electrodes of a pair of electrodes (not shown) arranged in the tube portion PB serves as a light emission point EP to generate light radially. Various arc tubes can be adopted as the arc tube 22a, for example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, or the like.

  The concave mirror 22b is an anamorphic reflecting mirror that reflects the light beam emitted from the arc tube 22a and emits it forward. The reflecting surface RF of the concave mirror 22b is one of the two planes shown in FIG. 2A that are perpendicular to each other and include the lamp optical axis XA that is the optical axis portion of the light source lamp unit 20 in the system optical axis SA. That is, the horizontal section HS cut out about the first plane (plane parallel to the XZ plane including the lamp optical axis XA) and the other plane shown in FIG. 2B, that is, the second plane (YZ including the lamp optical axis XA). And a vertical cross section PS cut with respect to a plane parallel to the plane), the curves have different curved shapes. More specifically, first, the shape of the reflecting surface RFa of the concave mirror 22b in the horizontal section HS is a parabolic shape with the light emitting point EP as a focal point. On the other hand, the shape of the reflection surface RFb of the concave mirror 22b in the vertical section PS is an elliptical shape having the light emission point EP on the lamp optical axis XA as the first focal point. That is, the reflecting surface RF is a non-rotationally symmetric concave shape in which the shape of the arc cut out on one plane is different from the shape of the arc cut off on the other plane. As a result, as shown in FIG. 3A, in the XZ plane including the lamp optical axis XA, the light beam emitted from the light emitting point EP toward the reflecting surface RFa is reflected by the reflecting surface RFa and then collimated. It is injected in the state made. Note that the XZ plane corresponding to the reflective surface RFa is parallel to a later-described reference plane. On the other hand, as shown in FIG. 3B, on the YZ plane including the lamp optical axis XA, the light beam emitted from the light emitting point EP toward the reflecting surface RFb is reflected by the reflecting surface RFb and then the lamp optical axis. The light is emitted so as to converge to the second focal point F2 on XA. Further, the light beam emitted from the light emitting point EP is also reflected at the corresponding portion of the reflecting surface RF at an intermediate portion other than the horizontal section HS and the vertical section PS of the concave mirror 22b, and is reflected on the XZ plane including the lamp optical axis XA. When projected, the light beam is parallel to the lamp optical axis XA, and when projected onto the YZ plane including the lamp optical axis XA, the light beam exits in a state of being converged to the second focal point F2 on the lamp optical axis XA. Is done. That is, the concave shape of the reflection surface RF of the concave mirror 22b is continuously changed from the parabolic reflection surface RFa to the elliptical reflection surface RFb. That is, the reflection surface RF is a curved surface that changes continuously without a step, and has a non-rotationally symmetric shape as a whole.

ｋ_ｘ，ｋ_ｙ：コーニック定数、ｃ_ｘ，ｃ_ｙ：半径の逆数、
Ａ_２ｎ：対称係数、Ｂ_２ｎ：非対称係数
に基づいて、上記焦点距離を実現するように各係数等を選定することで決定される。ここで、各コーニック定数ｋ_ｘ，ｋ_ｙは、−１＜ｋ_ｘ＜０の範囲内にあり、ｋ_ｙ＝−１（固定）である。また、ｃ_ｘ，ｃ_ｙに対応する半径は、第１焦点が一致するように調整する必要がある。上記アナモフィック非球面のシミュレーションに際して、反射面ＲＦｃの曲面形状に関する各係数は、ＸＺ面に垂直なＹ方向から見た場合には反射光が平行光となり、ＹＺ面に垂直なＸ方向から見た場合には反射光が収束光となるように定められている。なお、反射面ＲＦｃの曲面形状は、反射面ＲＦａ，ＲＦｂの焦点距離等の条件を前提としており、反射面ＲＦｃは、反射面ＲＦａ，ＲＦｂと滑らかにつながる。以上のようにして、反射面ＲＦａ，ＲＦｂ及び反射面ＲＦｃを設定することにより、図２（Ａ）等に示す発光点ＥＰから射出された光束は、反射面ＲＦａ，ＲＦｂ上で反射されるものに限らず反射面ＲＦｃまで含めた反射面ＲＦ上全体において、Ｙ方向から見ると平行光となり、Ｘ方向から見ると第２焦点Ｆ２に向かう収束光となるようにランプ部２１ａから射出される。凹面鏡２２ｂの具体的な作製方法については、上記のようなシミュレーション結果を基にして反転した形状の金型を作製する。この金型を利用して加熱したガラス材料等をプレス加工し、反射膜を形成することにより、上記のような特殊な形状の反射面ＲＦを有する凹面鏡２２ｂが作製される。なお、±Ｘ方向と±Ｙ方向とこれらの中間方向とを含む反射面ＲＦａ，ＲＦｂ，ＲＦｃの形状は、全体として円形の輪郭を有する滑らかな連続曲面であるため、後述する液晶パネル５１ａ，５１ｂ，５１ｃ（図１参照）に入射する光は、入射角度の方位依存性を抑えた一様性の高いものであり、プロジェクター１００による画像投影に適したものとなっている。 Hereinafter, the concave mirror 22b will be described in more detail. As shown in FIG. 4, the reflecting surface RF of the concave mirror 22b has a step gradually from a parabolic shape to an elliptical shape from the horizontal section HS to the vertical section PS on the reflecting surface RFc other than the reflecting surfaces RFa and RFb. It has changed without having a smooth continuous curved surface as a whole. Here, the shapes of the reflection surfaces RFa and RFb in the cross sections HS and PS are, for example, a parabolic focal length f = 12 on the reflection surface RFa, an elliptical first focal length f1 = 12, and a second focal length on the reflection surface RFb. It is set so that f2 = 60. Further, the specific curved surface shape of the reflecting surface RFc other than the reflecting surfaces RFa and RFb is the following sag amount expression of the anamorphic aspheric surface.

k _x , k _y : conic constant, c _x , c _y : reciprocal of radius,
A _2n is determined by selecting each coefficient or the like so as to realize the focal length based on a symmetric coefficient and B _2n : an asymmetric coefficient. Here, each of the conic constants k _x and k _y is in the range of −1 <k _x <0, and k _y = −1 (fixed). Further, a radius corresponding to the c _x, c _y must be adjusted such that the first focal point is coincident. In the simulation of the anamorphic aspherical surface, each coefficient relating to the curved surface shape of the reflective surface RFc is obtained when the reflected light becomes parallel light when viewed from the Y direction perpendicular to the XZ plane and when viewed from the X direction perpendicular to the YZ plane. Is defined so that the reflected light becomes convergent light. The curved surface shape of the reflection surface RFc is based on conditions such as the focal length of the reflection surfaces RFa and RFb, and the reflection surface RFc is smoothly connected to the reflection surfaces RFa and RFb. By setting the reflection surfaces RFa and RFb and the reflection surface RFc as described above, the light beam emitted from the light emission point EP shown in FIG. 2A and the like is reflected on the reflection surfaces RFa and RFb. In addition, the entire reflecting surface RF including the reflecting surface RFc is emitted from the lamp unit 21a so as to be parallel light when viewed from the Y direction and convergent light toward the second focal point F2 when viewed from the X direction. As for a specific method of manufacturing the concave mirror 22b, a mold having an inverted shape is manufactured based on the simulation result as described above. A concave mirror 22b having the reflection surface RF having a special shape as described above is manufactured by pressing a heated glass material or the like using this mold to form a reflection film. Note that the reflection surfaces RFa, RFb, and RFc including the ± X direction, the ± Y direction, and their intermediate directions are smooth continuous curved surfaces having a circular outline as a whole, and thus liquid crystal panels 51a and 51b described later. , 51c (see FIG. 1) is highly uniform with the azimuth dependency of the incident angle suppressed, and is suitable for image projection by the projector 100.

  As shown in FIG. 2A and the like, the secondary mirror 23a is inserted and fixed to the second sealing portion 24b on the opposite side of the concave mirror 22b so as to face the concave mirror 22b. The part PB covers substantially half of the opposite side of the concave mirror 22b. The secondary mirror 23a has a spherical reflecting surface RR, and the light directly emitted from the arc tube 22a toward the collimating lens 21b directly ahead, that is, the light not directed to the concave mirror 22b is temporarily stored in the arc tube 22a. Then, the light-emitting point EP or its periphery is allowed to pass through and is incident on the reflecting surface RF of the concave mirror 22b. That is, the sub mirror 23a functions as an auxiliary reflecting mirror that reflects the light emitted from the arc tube 22a to the side opposite to the concave mirror 22b so as to reversely travel, thereby increasing the light use efficiency.

  The collimating lens 21b is a lens that is disposed in the illuminated region on the downstream side of the optical path of the lamp unit 21a, and has a role of converting the light beam from the lamp unit 21a into a light beam substantially parallel to the lamp optical axis XA, that is, the illumination optical axis. is there. For this reason, the focal point of the collimating lens 21b coincides with the second focal point F2 of the reflecting surface RF. The light incident surface IS of the collimating lens 21b is a cylindrical aspherical surface, and is linear in the horizontal direction, that is, the X direction, as shown in FIG. 2A, and as shown in FIG. It is a hyperbolic shape corresponding to the shape of the reflecting surface RFb in the vertical direction, that is, the Y direction. That is, the generatrix of the light incident surface IS extends in a direction parallel to the XY plane perpendicular to the lamp optical axis XA and parallel to the first plane, that is, the XZ plane including the lamp optical axis XA (that is, the X direction). Yes. The light exit surface ES of the collimating lens 21b is a plane extending in parallel with the XY plane perpendicular to the lamp optical axis XA. Since the collimating lens 21b has the above-described surface shape, as shown in FIGS. 3 (A) and 3 (B), the total luminous flux emitted from the lamp unit 21a is aligned along the direction of the lamp optical axis XA. And inject in a substantially parallel state.

  In addition, by using the light source lamp unit 20 as described above, the shape of the light beam section FF can be made extremely flat as shown in FIG. In the present embodiment, the aspect ratio is 2: 1 or more. When the aspect ratio is a horizontal length of 2: 1 or more, even if two light beam cross-sections FF are stacked one above the other, a square or a horizontally long rectangle in the X direction parallel to a reference plane described later can be obtained.

  A light beam adjusting device 80 shown in FIG. 1 and the like is disposed on the downstream side of the optical path of the collimating lens 21, and includes a polarization branching member 81, a first reflecting prism 82, a second reflecting prism 83, and a half phase plate 84. And has an integrated configuration in which these are joined.

  Here, as shown in FIG. 6, the light flux adjusting device 80 is in a direction (Y direction) perpendicular to a reference plane that is an XZ plane including the system optical axis SA extending downstream of the light path of the light flux adjusting device 80. It has a two-story structure in which the polarization branching member 81 and the second reflecting prism 83 whose outer shapes coincide with each other are pasted together. The first reflecting prism 82 is affixed to the side surfaces SF1 and SF2 on the + X side of both the polarization branching member 81 and the second reflecting prism 83. That is, half H1 of the side surface 82a that is the side surface of the first reflecting prism 82 and extends parallel to the YZ plane is joined to the side surface SF1 of the polarization branching member 81 that is the first connection surface, and the side surface of the first reflecting prism 82 The remaining half H2 of 82a is joined to the side surface SF2 of the second reflecting prism 83 as a second connection surface.

  The polarization splitting member 81 is a prism having a quadrangular prism shape formed by bonding congruent triangular prisms 81a and 81b whose bottom surfaces are right-angled isosceles triangles on the surface of the hypotenuse, and a bonding surface of the triangular prisms 81a and 81b. In addition, a polarization separation film 81c extending in the Y direction between + X and + Z is formed. As shown in FIG. 2A, the light incident surface 81d of the polarization branching member 81 is disposed in the illuminated region on the downstream side of the optical path of the collimating lens 21, and extends parallel to the XY plane. The light beam SL having passed through the collimating lens 21 is incident on the light incident surface 81d. The polarization separation film 81c branches the incident light beam SL into a first partial light beam SL1 and a second partial light beam SL2 depending on the polarization state. That is, as shown in FIG. 2A, the polarization separation film 81c converts P-polarized light (first polarized light) having a polarization plane in the X direction out of the polarized light component of the light flux SL that is incident illumination light into the first partial light beam. It passes as SL1, and reflects S-polarized light (second polarized light) having a polarization plane in the Y direction as second partial light beam SL2.

  As shown in FIGS. 2A to 2C, the first partial light beam SL1 that has passed through the polarization separation film 81c travels toward the first light exit surface 81e that faces the light incident surface 81d. The first light exit surface 81e extends in parallel to the XY plane in the same manner as the light incident surface 81d. A 1/2 phase difference plate 84 is attached on the first light exit surface 81e, and the first partial light beam SL1 is converted from P-polarized light to S-polarized light by the 1/2 phase difference plate 84 to adjust the light flux. The light is emitted from the first light exit surface 81e of the apparatus 80 in a direction parallel to the system optical axis SA, that is, in the + Z direction.

  On the other hand, as shown in FIG. 2A, the second partial light beam SL <b> 2 reflected by the polarization separation film 81 c is emitted from the side surface SF <b> 1 on the + X side of the polarization branching member 81 and bonded to the polarization branching member 81. The light enters the first reflecting prism 82.

  As shown in FIG. 6 and the like, the first reflecting prism 82 as the first reflecting member is a triangular prism having a bottom isosceles triangle extending in a direction parallel to the system optical axis SA, that is, in the + Z direction. Bend the light path. Of the side surfaces extending in the + Z direction of the first reflecting prism 82, the first side surface 82a extending in parallel with the YZ plane has a shape that matches the polarization branching member 81 and both side surfaces SF1 and SF2 of the second reflecting prism 83. Yes. Further, the second side surface and the third side surfaces 82b and 82c, which are the remaining side surfaces of the first reflecting prism 82 and extend in the Z direction in the intermediate direction of ± X and −Y, are coated with, for example, reflecting films RM1 and RM2. The optical path of the second partial light beam SL2 is bent by internal reflection, and the second partial light beam SL2 is inverted with respect to the vertical direction, which is the Y direction perpendicular to the reference plane, and emitted toward the second reflecting prism 83.

  2B and 2C, the second partial light beam SL2 incident from the upper half H1 of the first side surface 82a of the first reflecting prism 82 is transmitted by the side surfaces 82b and 82c of the first reflecting prism 82. The optical path is bent and emitted from the lower half H2 of the first side face 82a toward the second reflecting prism 83. That is, the first reflecting prism 82 bends the optical path of the second partial light beam SL2 traveling in the + X direction in the −Y direction on the side surface 83b and further bends in the −X direction on the side surface 83b. As a result, as will be described in detail later, the second partial light beam SL2 is emitted from the first reflecting prism 82 in an inverted state.

  As shown in FIG. 6 and the like, the second reflecting prism 83, which is the second reflecting member, is configured by bonding congruent triangular prisms 83a and 83b whose bottom surfaces are right-angled isosceles triangles, similarly to the polarization branching member 81. In addition, a reflecting film 83c extending in the Y direction, which is an intermediate direction between −X and + Z, is formed on the bonding surface of the triangular prisms 83a and 83b. Here, one of the three side surfaces of the triangular prism 83a is the side surface SF2 joined to the first reflecting prism 82. Of the remaining two side surfaces of the triangular prism 83a, the hypotenuse surface is a reflection portion by the reflection film 83c, and the remaining one is the second light exit surface 83d.

  The second partial light beam SL2 incident from the side surface SF2 of the second reflecting prism 83 has its optical path bent by the reflective film 83c, proceeds toward the second light exit surface 83d extending parallel to the XY plane, and from the light beam adjusting device 80. The light is emitted in a direction parallel to the system optical axis SA, that is, in the + Z direction. Due to the reflection at the first and second reflecting prisms 82 and 83 of the polarization branching member 81, the second partial light beam SL2 is emitted from the second reflecting prism 83 in a state of being reversed left and right.

  Hereinafter, the reversal of the light flux in the light flux adjusting device 80 will be described in detail with reference to FIG. 7A to 7D is an axis at a position symmetrical to the lamp optical axis XA across the reference plane SS extending in the XZ direction. First, FIGS. 7A and 7B show the light beam SL incident from the position above the lamp optical axis XA with respect to the traveling direction, that is, on the + Y side, before the branching by the polarization separation film 81c of the illumination light beam. The optical path is schematically shown. In this case, as shown in FIG. 7A, the optical path of the first partial light beam SL1 branched from the light beam SL travels straight in the + Z direction, and is always kept above the lamp optical axis XA, that is, the + Y side. It is injected from the position. On the other hand, as shown in FIGS. 7A and 7B, the optical path of the second partial light beam SL2 branched from the light beam SL is bent in the light beam adjusting device 80, and finally, As shown in FIG. 7A, the light is emitted from a position below the sub optical axis XA ′, that is, from the −Y side.

  On the other hand, FIGS. 7 (C) and 7 (D) show a light beam incident from a position lower than the lamp optical axis XA, that is, a position on the −Y side with respect to the traveling direction before the illumination light beam is branched by the polarization separation film 81c. FIG. 2 schematically shows an optical path of SL. In this case, the optical path of the first partial light beam SL1 is always emitted from a position that is kept below the lamp optical axis XA, that is, on the −Y side. On the other hand, the optical path of the second partial light beam SL2 is emitted from a position above the sub optical axis XA ′, that is, from the + Y side.

  As described above, the light component incident on the light beam adjusting device 80 is branched according to the polarization state and follows a different optical path. At this time, the first partial light beam SL1 passes through the polarization branching member 81 as it is and is spatially transmitted. However, the second partial light beam SL2 is spatially reversed in the vertical direction, that is, the upper and lower Y directions, with respect to the reference plane SS including the system optical axis SA due to reflection by the first reflecting prism 82. .

  Further, as shown in FIGS. 8A and 8B, the second partial light beam SL2 is also inverted in the left and right X directions. That is, as shown in FIG. 8A, the first partial light beam SL1 out of the light incident on the light beam adjusting device 80 from the left side of the lamp optical axis XA is the system optical axis extending downstream of the light path of the light beam adjusting device 80. The second partial light beam SL2 is emitted from the lower right side of the system optical axis SA, whereas the second partial light beam SL2 is emitted from the upper left side of the SA. On the other hand, as shown in FIG. 8B, for the light incident on the light beam adjusting device 80 from the right side of the lamp optical axis XA, the first partial light beam SL1 is the system optical axis extending downstream of the light path of the light beam adjusting device. The second partial light beam SL2 is emitted from the lower left side of the system optical axis SA, whereas it is emitted from the upper right side of the SA.

  As described above, in the light beam adjusting device 80, the adjusted first partial light beam SL1 and second partial light beam SL2 are both in the S-polarized state, and the first partial light beam SL1 is spatially non-inverted. On the other hand, the second partial light beam SL2 is spatially inverted in the vertical and horizontal directions, and is emitted in a state substantially parallel to the system optical axis SA. At this time, the first light exit surface 81e and the second light exit surface 83d are formed on the same plane, and the first partial light beam SL1 and the second partial light beam SL2 are continuous into one. Is emitted from the light beam adjusting device 80 as a typical illumination light beam.

  Returning to FIG. 1, the homogenizing optical system 30 includes first and second lens arrays 31 and 32 and a superimposing lens 35. The first and second lens arrays 31 and 32 are, for example, fly-eye lenses each composed of a plurality of element lenses arranged in a matrix. Among these, the luminous flux emitted from the light source lamp unit 20 is divided into a plurality of partial luminous fluxes by the element lenses constituting the first lens array 31. Further, the partial lenses from the first lens array 31 are emitted at an appropriate divergence angle by the element lenses constituting the second lens array 32. The superimposing lens 35 appropriately superimposes the illumination light emitted from the second lens array 32 as a whole, thereby enabling superimposing illumination on the liquid crystal light valves 50a, 50b, and 50c of the respective colors provided in the light modulation unit 50. As described above, the illumination device 10 emits illumination light in a state suitable for projection image formation by the projector 100.

  As described above, in the present embodiment, in the light beam adjusting device 80, the first partial light beam SL1 is kept spatially non-inverted, the second partial light beam SL2 is spatially reversed, and the first and second parts Since the light beams SL1 and SL2 are emitted in a state in which the polarization state is uniform, it is not necessary to pass through the polarization beam splitter array after passing through the lens arrays 31 and 32 for homogenization, and the illumination efficiency can be improved. Further, the lens arrays 31 and 32 do not need to be decentered or the like, and can have a simple structure. Further, in this illumination device 10, since the first partial light beam SL1 and the second partial light beam SL2 are reversed and taken out at the time of the polarization conversion for aligning the polarization state by the light beam adjusting device 80, the illumination formed by the concave mirror 22b. Even if there is illuminance unevenness in the luminous flux, it is possible to obtain an illumination light beam with less bias that reduces the illuminance unevenness.

  As a modification of the present embodiment, as shown in FIG. 9, a ½ phase difference plate 84 can be provided on the second light exit surface 83 d of the second reflecting prism 83. In this case, the first partial light beam SL1 is emitted in the state of P-polarized light (first polarized light), and the second partial light beam SL2 is changed from S-polarized light (second polarized light) to P-polarized light (second polarized light) by the half phase plate 84. The first polarized light is converted and emitted. That is, in this case, the entire light flux adjusting device 80 emits the illumination light flux in a state of being aligned with the P-polarized light.

  As another modification of the present embodiment, as shown in FIG. 10, the light exit surface ES of the collimating lens 21b is joined to the light incident surface 81d of the light flux adjusting device 80, and the collimating lens 21b and the light flux adjusting device are joined. 80 may be integrated.

  Hereinafter, the configuration and operation of the entire projector 100 will be described with reference to FIG. The color separation light guide 40 located on the downstream side of the optical path of the illumination device 10 includes first and second dichroic mirrors 41a, 41b, reflection mirrors 42a, 42b, 42c, three field lenses 43a, 43b, 43c, Relay lenses 44a and 44b, and separates the illumination light emitted from the illumination device 10 into three colors of red (R), green (G), and blue (B), and separates each color light in the subsequent stage. Guide to the liquid crystal light valves 50a, 50b, 50c. More specifically, first, the first dichroic mirror 41a reflects the R illumination light LR out of the three RGB colors and transmits the G and B illumination lights LG and LB. The second dichroic mirror 41b reflects the G illumination light LG of the two colors GB and transmits the B illumination light LB. That is, the red light LR reflected by the first dichroic mirror 41a is guided to the red optical path OP1 with the field lens 43a, and the green light LG transmitted through the first dichroic mirror 41a and reflected by the second dichroic mirror 41b is The blue light LB guided to the green light path OP2 having the field lens 43b and passing through the second dichroic mirror 41b is guided to the blue light path OP3 having the field lens 43c. The field lenses 43a, 43b, and 43c for the respective colors allow the partial light beams that are emitted from the second lens array 32, pass through the superimposing lens 35, and enter the light modulation unit 50 to be covered by the liquid crystal light valves 50a, 50b, and 50c. On the irradiation area, the incident angle is adjusted so as to have an appropriate convergence or divergence with respect to the system optical axis SA.

  The light modulation unit 50 includes three liquid crystal light valves 50a, 50b, and 50c into which the three colors of illumination lights LR, LG, and LB are respectively incident. Each of the liquid crystal light valves 50a, 50b, and 50c includes a liquid crystal panel 51a, 51b, and 51c disposed in the center, an incident-side polarization filter 52a, 52b, and 52c disposed on the upstream side of the optical path, and a downstream of the optical path. Side exit side polarization filters 53a, 53b, and 53c, respectively. Each color light LR, LG, LB incident on each of the liquid crystal light valves 50a, 50b, 50c is a pixel unit in accordance with a drive signal or a control signal input as an electrical signal to each of the liquid crystal light valves 50a, 50b, 50c. The intensity is modulated with. Each of the liquid crystal panels 51a, 51b, and 51c is a transmissive liquid crystal panel, and a description thereof is omitted. However, a light transmissive incident side substrate having a transparent electrode or the like, and a light having a pixel electrode or the like. A transparent driving substrate; and a liquid crystal layer hermetically sealed between the incident side substrate and the driving substrate.

  The color synthesizing unit 60 is a cross dichroic prism for synthesizing a color image, and includes a first dichroic film 61 for reflecting R light and a second dichroic film 62 for reflecting B light in a plane. It is arranged in a visual X shape. The color composition unit 60 reflects the red light LR from the liquid crystal light valve 50a by the first dichroic film 61 and emits the green light LG from the liquid crystal light valve 50b to the dichroic films 61 and 62. The blue light LB from the liquid crystal light valve 50c is reflected by the second dichroic film 62 and emitted to the left in the traveling direction.

  The projection optical system 70 projects the image light combined by the color combining unit 60 as a projection lens as a color image on a screen (not shown).

  The projector 100 according to the present embodiment can obtain an illumination light beam with less bias with uniform polarization state and reduced illuminance unevenness by the light beam adjusting device 80 provided in the illumination device 10. Therefore, the projector 100 according to the present embodiment can be thinned as a whole while maintaining the quality of the illumination light.

[Second Embodiment]
Hereinafter, with reference to FIG. 11, a lighting apparatus and the like according to the second embodiment of the present invention will be described. The illumination device according to the present embodiment is a modification of the light source lamp unit in the illumination device 10 shown in FIG.

  As shown in FIG. 11, in the illumination device 110 according to the present embodiment, the light source lamp unit 120 includes a lamp unit 121a and a collimating lens 121b. The lamp unit 121a includes an arc tube 22a, a concave mirror 122b, a secondary mirror 123a, and a base 125.

  The concave mirror 122b is a modification of the concave mirror 22b of the illumination device 10 shown in FIG. 2B, which is an anamorphic reflector. Specifically, the concave mirror 122b has a shape obtained by cutting the lower half (−Y side) of the concave mirror 22b on the XZ plane including the lamp optical axis XA and leaving only the upper half (+ Y side). In this case, for example, the curved surface shape of the reflecting surface RF of the concave mirror 122b passes through the parallelizing lens 121b by making the convergence degree gentler than the curved surface shape of the reflecting surface RF of the concave mirror 22b shown in FIG. After that, the aspect ratio and the like in the irradiated area are appropriately adjusted so as to be the same as those in the illumination device 10 of the first embodiment. The arc tube 22a and the concave mirror 122b are fixed at predetermined positions according to the grooves provided in the base 125.

  The secondary mirror 123a is arranged so as to face the concave mirror 22b across the arc tube 22a in the vertical direction, that is, the Y direction perpendicular to the lamp optical axis XA. The sub mirror 123a is fixed at a predetermined position by a groove provided in the base 125, and covers approximately half of the tube bulb portion PB of the arc tube 22a opposite to the concave mirror 122b. That is, the reflecting surface RR of the secondary mirror 123a has a hemispherical shape corresponding to the surface shape of the lower half of the tube portion PB. The sub-mirror 123a temporarily returns a light beam directed downward (−Y side) of the light emitted from the light emitting tube 22a by the reflecting surface RR, that is, light not directed to the concave mirror 122b, into the light emitting tube 22a to emit the light emission point EP or It functions as an auxiliary reflecting mirror that passes through its periphery and enters the reflecting surface RF of the concave mirror 122b. As described above, the lamp unit 121a can emit high-density light as compared with the case where the secondary mirror 123a is not provided.

  The collimating lens 121b is a lens having a role of changing the light beam from the lamp unit 121a into a light beam substantially parallel to the lamp optical axis XA, and is adapted to the shape of the sub mirror 123a. That is, the collimating lens 121b is modified in the same manner as in the case of the secondary mirror 123a, and is cut so that at least the upper half (+ Y side) of the collimating lens 21b shown in FIG. It has a shape. Note that the refractive power of the collimating lens 121b is lower than the refractive power of the collimating lens 21b shown in FIG. 2B, etc., corresponding to the curved surface shape of the concave mirror 122b, enabling the collimation of the luminous flux. Yes.

  When the light source lamp unit 120 as described above is used, light having a light flux density that is approximately twice that of normal light is emitted toward the collimating lens 121b due to reflection by the secondary mirror 123a. In the case of this embodiment, unlike the first embodiment, the distribution state of the light flux may increase the illuminance unevenness of the emitted illumination light flux, but the light flux adjusting device 80 is provided on the downstream side of the light path of the light source lamp unit 120. Since it uses, the illuminating device 110 can inject | emit an illumination light beam in the state which reduced the illumination intensity nonuniformity. Further, similarly to the illumination device 10, the illumination device 110 can be assembled to the projector 100 shown in FIG.

  In addition, as shown in FIG. 12, the light source lamp unit 120 may be installed in a state of being inverted in the vertical direction, that is, the Y direction. In this case, the entire illumination device 110 can be made thin in the Y direction, and the illumination light beam can be emitted in a state where illuminance unevenness is reduced.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments.

  First, in each embodiment, an anamorphic reflection surface RF having a parabolic shape for a horizontal cross section and an elliptic shape for a vertical cross section is used. In the present invention, the aspect ratio of the light incident surface is 2: 1 or more. As long as a light beam having an extremely flat light beam cross-section FF, that is, a sheet light beam can be produced, the shape of the arc in the horizontal cross section and the vertical cross section are not limited to the anamorphic reflecting surface as described above. A surface having various non-rotationally symmetric concave shapes that are different from the arc shape can be applied as the reflecting surface RF of the concave mirrors 22b and 122b. For example, the concave mirror may have an elliptical reflecting surface having different eccentricity, focal length, and the like between the horizontal section and the vertical section.

  In the first embodiment, the secondary mirror 23a is used, but a configuration without the secondary mirror 23a is also possible.

  In each of the above embodiments, the horizontal section HS has a parabolic shape and the vertical section PS has an elliptical shape. Conversely, the horizontal section HS has an elliptical shape, and the vertical section PS has a vertical shape. May be parabolic. For example, for a vertical projector, the shape of the horizontal section HS can be an ellipse, and the shape of the vertical section PS can be a parabola.

  Further, in each of the above embodiments, the first partial light beam SL1 passes through the polarization separation film 81c of the polarization branching member 81, and the second partial light beam SL2 is reflected and passes through the first reflecting prism 82 and the like. The light exit surfaces 81e and 83d from which the light beams SL1 and SL2 are emitted are arranged in parallel to the incident surface 81d. However, the configuration of the polarization branching member 81 is not limited to this, and for example, the light exit surfaces 81e and 83d may be arranged perpendicular to the incident surface 81d. That is, in the polarization separation film 81c, the first partial light beam SL1 is reflected and the second partial light beam SL2 passes, and the first reflecting prism 82 and the like are provided on the exit side of the second partial light beam SL2 that has passed through the polarization branching member 81. The light emission surfaces 81e and 83d may be perpendicular to the incident surface 81d.

  Further, in each of the above embodiments, in the light flux adjusting device 80, the reflection films RM1 and RM2 are applied to the second side surface and the third side surfaces 82b and 82c of the first reflecting prism 82, which is the first reflecting member, and bent twice. However, when the light beam is bent by total reflection at the second side surface and the third side surfaces 82b and 82c, the reflection films RM1 and RM2 need not be provided. Further, instead of the first reflecting prism 82, for example, two mirrors may be installed. The second reflecting prism 83, which is the second reflecting member, is formed by bonding two triangular prisms 83a and 83b. The second reflecting prism 83 is formed by applying a reflective film 83c to the triangular prism 83a. It may be configured to function as a second reflecting member. Also in this case, when the light beam can be bent by total reflection, the reflection film 83c need not be provided. Further, the second reflecting member may be constituted by a mirror or PBS instead of the triangular prism 83a.

  In the above embodiment, an example in which the present invention is applied to a projector including the transmissive liquid crystal light valves 50a, 50b, and 50c has been described. However, the present invention also applies to a projector including a reflective liquid crystal light valve. It is possible to apply. Here, “transmission type” means that the liquid crystal light valve is a type that transmits light, and “reflection type” means that the liquid crystal light valve is a type that reflects light. ing.

  Moreover, as a projector, there are a front projection type projector that projects an image from the direction of observing the projection surface and a rear projection type projector that projects an image from the side opposite to the direction of observing the projection surface. The configuration of the projector shown in 1 etc. can be applied to any of them.

  In addition, the illumination devices 10 and 110 of each of the above embodiments are not limited to projectors, and can be applied to various optical devices that require parallel light beams with uniform polarization states.

  DESCRIPTION OF SYMBOLS 10,110 ... Illuminating device 20, 120 ... Light source lamp unit, 21a, 121a ... Lamp part, 21b, 121b ... Parallelizing lens, 22a ... Arc tube, 22b, 122b ... Concave mirror, RF, RFa, RFb, RFc ... Reflection , 23a, 123a ... secondary mirror, 30 ... homogenizing optical system, 40 ... color separation light guide, 50 ... light modulator, 50a, 50b, 50c ... liquid crystal light valve, 51a, 51b, 51c ... liquid crystal panel, 60 ... Color synthesis unit, 70 ... Projection optical system, 100 ... Projector, HS ... Horizontal section, PS ... Vertical section, SA ... System optical axis

Claims (12)

An arc tube for generating light;
Of the shapes cut by two planes perpendicular to each other including the system optical axis, the shape of the arc cut by one plane is different from the shape of the arc cut by the other plane and has a non-rotationally symmetric concave shape An anamorphic reflector that includes a reflecting surface and reflects the light from the arc tube at the reflecting surface to emit illumination light;
A collimating lens that is arranged on the downstream side of the light path of the arc tube and the anamorphic reflector and that collimates the transmitted light;
Arranged on the downstream side of the optical path of the collimating lens, splitting incident light into a first partial light beam and a second partial light beam having different polarization states, and maintaining the first partial light beam in a spatially non-inverted state; The second partial light beam is spatially inverted, the polarization state of at least one of the first and second partial light beams is converted, and the first and second partial light beams are emitted in a state where the polarization states are aligned. An illumination device comprising: a light flux adjusting device.   The light beam adjusting device reverses the second partial light beam by bending a light path, and a polarization branching member that branches incident light into the first partial light beam of the first polarization and the second partial light beam of the second polarization. The lighting device according to claim 1, comprising first and second reflecting members. The first and second reflecting members are first and second prisms that respectively bend the optical path by internal reflection.
The illuminating device according to claim 2, wherein the light flux adjusting device has an integrated configuration in which the polarization branching member and the first and second prisms are joined. The polarization branching member includes a light incident surface that receives light incident on the light flux adjusting device, a first light exit surface that emits the first partial light beam to the outside, and a first connection surface that extracts the second partial light beam. Have
The first reflecting member has a second connection surface that is connected to the first connection surface of the polarization branching member and allows the second partial light beam to pass therethrough and takes out the second partial light beam,
The second reflecting member has a second light emitting surface that is connected to the second connection surface of the first reflecting member to allow the second partial light beam to pass therethrough and to emit the second partial light beam to the outside. The lighting device according to any one of claims 2 and 3. The first reflecting member has two reflecting surfaces, and the second partial light beam that has passed through the polarization branching member is perpendicular to a reference plane including a system optical axis that extends downstream of the light path of the light beam adjusting device. Inverting the second partial light beam with respect to a direction perpendicular to the reference plane by bending twice in a plane perpendicular to the traveling direction;
The second reflecting member has one reflecting surface, and the second partial light flux that has passed through the first reflecting member is bent once in a direction perpendicular to the traveling direction in a plane parallel to the reference plane. Item 5. The lighting device according to Item 4.   6. The light flux adjusting device according to claim 1, further comprising a half-wave plate on one of the first light exit surface and the second light exit surface. 7. Lighting device. The one plane extends parallel to a reference plane including a system optical axis extending downstream of the optical path of the light flux adjusting device,
In the reflecting surface of the anamorphic reflector, the shape cut out on the one plane draws a parabolic arc with the center between the electrodes of the arc tube as the focus, and the shape cut off on the other plane The illuminating device according to any one of claims 1 to 6, wherein an ellipsoidal arc having a focal point of a parabolic arc as a first focal point is drawn.   The illumination device according to any one of claims 1 to 8, wherein an aspect ratio of the light incident surface of the light flux adjusting device is 2: 1 or more.   The said arc tube has any auxiliary reflector which reflects the light inject | emitted from the center between the electrodes of the said arc tube to the opposite side to the said anamorphic-type reflector in a reverse direction. The lighting device according to claim 1.   The lighting device according to claim 1, wherein the collimating lens is bonded to the light incident surface of the light flux adjusting device.   The illumination device according to any one of claims 1 to 10, wherein the collimating lens is a cylindrical lens having a cylindrical aspherical surface. The lighting device according to any one of claims 1 to 11,
A light modulation device illuminated by a light beam emitted from the illumination device;
A projection optical system for projecting a light beam emitted from the light modulation device;
A projector comprising:

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