JP4066773B2 - Projection display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection display device, and more particularly to a projection display device including a reflection type illumination optical system for illumination for image projection.
[0002]
[Prior art]
A digital micromirror device is known as a reflective display panel used in a projection display device. The digital micromirror device has a plurality of micromirrors, and each micromirror can be rotated around an axis having a predetermined inclination (for example, 45 °) with respect to its long side or short side. Has been. The ON / OFF state for each pixel is obtained when each micromirror has two tilt states (for example, ± 12 °). When the micromirror is in the ON state, the reflected illumination light reaches the screen after being guided to the entrance pupil of the projection optical system. On the other hand, when the micromirror is in the OFF state, nothing is displayed on the screen because the reflected illumination light is reflected in a direction different from the entrance pupil position of the projection optical system.
[0003]
In a projection display device equipped with a digital micromirror device that operates as described above, the illumination light reflected from the micromirror in the ON state is illuminated from the oblique direction to the entire screen of the digital micromirror device. Must be efficiently guided to the entrance pupil of the projection optical system. At the same time, it is necessary to prevent the illumination light reflected by the micromirror in the OFF state from entering the entrance pupil of the projection optical system. Therefore, various types of illumination optical systems have been conventionally proposed. For example, Patent Document 1 proposes an illumination optical system including an elliptical mirror and a condenser lens.
[0004]
[Patent Document 1]
Japanese Patent No. 3121843
[0005]
[Problems to be solved by the invention]
When a lens is used in the illumination optical system, chromatic aberration occurs, and the number of parts increases to correct it. Since the reflecting surface has a larger power that can be borne per surface than the lens surface, the use of the reflecting surface in the illumination optical system can reduce the number of components and no chromatic aberration. However, when a reflecting surface is used in combination with a lens surface as in the illumination optical system described in Patent Document 1, it becomes difficult to obtain sufficient optical performance as the illumination optical system, resulting in an increase in the cost of the display device. And will lead to an increase in size.
[0006]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a low-cost and compact projection display device having high optical performance in an illumination optical system.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, a projection display device according to a first aspect of the present invention guides light from a light source to a display panel with an illumination optical system, and displays a display image of the display panel illuminated thereby on a screen with a projection optical system. A projection display device for projecting, comprising: a condensing optical system that condenses light from the light source to form a secondary light source; and an incident end face near the secondary light source and is collected by the condensing optical system. Light intensity uniformizing means for equalizing the spatial energy distribution of the emitted light, and the emitted light color is changed in a time-division manner for color display near the incident end face or the exit end face of the light intensity uniformizing means. The illumination optical system includes a color filter and a reflection optical system that forms an image of an emission end face of the light intensity uniformizing unit on a panel surface of the display panel.The display panel is a reflective type, the illumination optical system illuminates the panel surface of the display panel from an oblique direction, and the projection optical system is oblique telecentric on the display panel side,The reflective optical system has only first and second concave reflective surfaces as optical surfaces having power, and a tertiary light source is formed from the secondary light source by the first concave reflective surface, and the second concave surface The light from the tertiary light source is guided to the entrance pupil of the projection optical system by a reflecting surface.The vertical direction of the panel surface of the display panel y Axial direction and lateral direction z In the axial direction, at least one of the first and second concave reflecting surfaces is y Axial and z A light beam having an asymmetric free curved surface shape in the axial direction and passing through the display panel from the center of the exit end surface of the light intensity uniformizing means and reaching the center of the entrance pupil of the projection optical system Concerning the radius of curvature at the point where it hits the concave reflecting surface, the concave reflecting surface having the above-mentioned free-form surface is the following conditional expression (i) The free-form surface shape does not have plane symmetryIt is characterized by that.
| CRy | < | CRz | ... (i)
However,
CRz : Radius of curvature cut by a plane including the incident light beam and the outgoing light beam on the concave reflecting surface having a free-form surface shape,
CRy : A radius of curvature that is perpendicular to the plane that includes the incident light beam and the outgoing light beam on the concave reflecting surface having a free-form surface shape, and is cut by the plane that includes the normal vector of the concave reflecting surface;
Is.
[0008]
  According to a second aspect of the present invention, there is provided a projection display apparatus according to the first aspect,Further, the optical axis of the light intensity uniformizing means and the optical axis of the projection optical system are substantially parallel, or the optical axis direction of the light intensity uniformizing means and the normal direction of the panel surface of the display panel Is a plane reflecting surface between the first concave reflecting surface and the second concave reflecting surface so that they substantially coincide with each other.It is characterized by having.
[0009]
  A projection display device according to a third invention provides:A projection display device that guides light from a light source to a display panel by an illumination optical system and projects a display image of the illuminated display panel onto a screen by a projection optical system, and condenses the light from the light source A condensing optical system that forms a secondary light source, and a light intensity equalizing means that has an incident end face near the secondary light source and uniformizes the spatial energy distribution of the light collected by the condensing optical system A color filter that changes the emitted light color in a time-division manner for color display near the entrance end face or the exit end face of the light intensity uniformizing means, and an image of the exit end face of the light intensity uniformizing means on the display panel A reflective optical system formed on the panel surface of the display panel, the illumination optical system having the reflective optical system, the display panel is of a reflective type, and the illumination optical system illuminates the panel surface of the display panel from an oblique direction. The reflection optical system is power The optical surface has only the first and second concave reflecting surfaces, and the optical axis of the light intensity uniformizing means and the optical axis of the projection optical system are substantially parallel or the light intensity. A plane reflecting surface is provided between the first concave reflecting surface and the second concave reflecting surface so that the optical axis direction of the uniformizing means and the normal direction of the panel surface of the display panel substantially coincide. Then, a tertiary light source is formed from the secondary light source by the first concave reflecting surface, and light from the tertiary light source is guided to the entrance pupil of the projection optical system by the second concave reflecting surface, and the display The vertical direction of the panel surface of the panel y Axial direction and lateral direction z In the axial direction, at least one of the first and second concave reflecting surfaces is y Axial and z Each has an asymmetric free-form surface shape in the axial direction,With respect to the radius of curvature at the point where a light beam that passes through the display panel from the center of the exit end face of the light intensity uniformizing means and reaches the center of the entrance pupil of the projection optical system hits the concave reflecting surface of the free-form curved surface, The concave reflecting surface having a curved surface shape satisfies the following conditional expression (i), and the free curved surface shape has no surface symmetry.
    | CRy | <| CRz |… (i)
  However,
    CRz: radius of curvature cut by a plane including the incident light beam and the outgoing light beam on the concave reflecting surface having a free-form surface shape,
    CRy: a radius of curvature that is perpendicular to the plane that includes the incident and exit rays on the concave reflecting surface having a free-form surface, and that is cut by the plane that includes the normal vector of the concave reflecting surface;
It is.
[0010]
  A projection display device according to a fourth invention isNo.In the configuration of the second or third invention,The first and second concave reflecting surfaces are both y Axial and z Free-form surface shape that is asymmetric with respect to the axial directionIt is characterized by having.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a projection display apparatus embodying the present invention will be described with reference to the drawings. 1 to 4 show an embodiment of a projection display device. FIG. 1 is a perspective view showing a schematic optical configuration of the entire display device, and FIGS. 2 to 4 are a perspective view, a bottom view, and a side view showing main parts thereof. 1-4, LA is a light source lamp, L1 is a light source, L2 is an elliptical reflector, RI is a rod integrator, CW is a color wheel, M1 to M8 are first to eighth mirrors, SL is an illumination system pupil, and SP is The projection system pupil, PA is a display panel, OP is an optical engine unit, and SC is a screen. Although a digital micromirror device is assumed here as the display panel (PA), the present invention is not limited to this. Other non-light emitting / reflective (or transmissive) display elements and light valves (liquid crystal display elements, etc.) suitable for a projection optical system (PL) described later may be used.
[0012]
As shown in FIG. 1, the light engine lamp (LA) to the seventh mirror (M7) are the optical engine section (OP) that constitutes the main part of the projection display device. In the optical engine section (OP), as shown in FIGS. 2 to 4, an elliptical reflector (L2), a rod integrator (RI), a color wheel (CW), and first to third mirrors (M1 to M3). ), The light from the light source (L1) is guided to the display panel (PA). The main part is shown in FIG. FIG. 5 is a schematic representation of the layout and the passage of rays by replacing a reflective optical element with a transmissive type. The display image of the display panel (PA) illuminated by the illumination optical system is projected onto the screen (SC) by the projection optical system (PL, FIG. 5) including the fourth to eighth mirrors (M4 to M8).
[0013]
The configuration of each part will be described in more detail. As shown in FIGS. 2 to 4, the light source lamp (LA) includes a light source (L1) and an elliptic reflector (L2). The elliptical reflector (L2) is a condensing optical system that collects the light from the light source (L1) to form a secondary light source, and the light emitted from the light source lamp (LA) is incident on the end surface of the rod integrator (RI). (t1) An image is formed in the vicinity. A rotating paraboloidal mirror or a spherical mirror may be used instead of the elliptical reflector (L2), but in that case, in order to collect the light from the light source (L1), it is combined with a condensing lens or the like. It is necessary to configure an optical optical system.
[0014]
The light emitted from the light source lamp (LA) enters the rod integrator (RI). The rod integrator (RI) is a hollow rod type light intensity equalizing means formed by bonding four plane mirrors, and has an incident end face (t1) in the vicinity of the secondary light source as described above. The light incident from the incident end face (t1) is mixed by being repeatedly reflected by the side surface (that is, the inner wall surface) of the rod integrator (RI), and the spatial energy distribution of the light is made uniform and emitted. Injected from the end face (t2). The shape of the incident end face (t1) and the exit end face (t2) of the rod integrator (RI) is a quadrangle similar to the display panel (PA). Further, as can be seen from FIG. 5, the entrance end face (t1) of the rod integrator (RI) is conjugate to the illumination system pupil (SL), and the exit end face (T2) of the rod integrator (RI) is the display panel ( It is conjugate to the panel surface of (PA). Due to the mixing effect, the luminance distribution on the exit end face (t2) is made uniform, so that the display panel (PA) is illuminated efficiently and uniformly. The rod integrator (RI) is not limited to a hollow rod but may be a glass rod made of a quadrangular prism-shaped glass body. Further, as long as it matches the panel surface shape of the display panel (PA), the side surfaces are not limited to four. Accordingly, examples of the rod integrator (RI) to be used include a hollow cylinder formed by combining a plurality of reflecting mirrors, a glass body having a polygonal column shape, and the like.
[0015]
In the vicinity of the exit end face (t2) of the rod integrator (RI), a color wheel (CW) for changing the emitted light color in a time division manner for color display is arranged. The color wheel (CW) is composed of a color filter for illuminating the display panel (PA) in a color sequential manner, and changes the color of the emitted light by rotating the filter portion at the illumination light transmission position. The position of the color wheel (CW) is not limited to the vicinity of the injection end surface (t2) of the rod integrator (RI). The position may be set according to the arrangement of other optical elements, for example, the color wheel (CW) may be arranged in the vicinity of the incident end face (t1) of the rod integrator (RI). Still further, a UV (ultraviolet ray) -IR (infrared ray) cut filter may be arranged to cut ultraviolet rays and infrared rays from the illumination light.
[0016]
The light emitted from the color wheel (CW) is incident on a reflection optical system including the first to third mirrors (M1 to M3). Then, the reflection optical system forms an image of the exit end face (t2) of the rod integrator (RI) on the panel surface of the display panel (PA). The power for performing the image formation is borne by the first and third mirrors (M1, M3). That is, the reflecting surfaces of the first and third mirrors (M1, M3) are concave reflecting surfaces, and the reflecting surface of the second mirror (M2) is a planar reflecting surface. The secondary light source near the entrance end face (t1) of the rod integrator (RI) is re-imaged by the concave reflecting surface of the first mirror (M1), and a tertiary light source is formed near the illumination system pupil (SL) position. The Light from the tertiary light source is guided to the display panel (PA) by the concave reflecting surface of the third mirror (M3). Light incident on the display panel (PA) is spatially intensity-modulated by being reflected by each micromirror in an ON / OFF state (for example, an inclination state of ± 12 °). At that time, only the light reflected by the micro mirror in the ON state is incident on the projection optical system (PL) composed of the fourth to eighth mirrors (M4 to M8), and the power of the concave reflecting surface of the third mirror (M3). Is efficiently guided to the entrance pupil (SP) of the projection optical system (PL). Then, the light is projected onto the screen (SC) by the projection optical system (PL).
[0017]
In this embodiment, the reflecting optical system has only two concave reflecting surfaces as optical surfaces having power as described above. For this reason, it is possible to achieve a reduction in the number of parts of the illumination optical system and a reduction in size, and since chromatic aberration does not occur, color unevenness does not occur and a decrease in illuminance can be suppressed. Therefore, it is possible to use optical components that are compact and advantageous in terms of mass productivity and cost while maintaining good optical performance, and it is possible to achieve cost reduction, compactness, and high performance of display devices. Become.
[0018]
Further, as can be seen from the optical path shown in FIG. 5, the projection optical system (PL) has an oblique telecentric configuration on the display panel (PA) side. In the case of a telecentric optical system, it is designed so that the principal rays of the light flux from each image height out of the incident light from the display panel to the projection optical system are substantially parallel to each other, so that both the illumination optical system and the projection optical system It is possible to make the sizes substantially equal. However, since the optical burden on the projection optical system becomes large, there is a demerit such as an increase in the number of lenses when trying to satisfy the optical performance. If two mirrors (M1, M3) having concave reflecting surfaces are used as optical elements having power in the illumination optical system as in this embodiment, the minimum number of illumination optical systems can be configured in principle. Therefore, a telecentric projection optical system (PL) -oriented illumination optical system can be formed on the display panel (PA) side. Since the number of reflection surfaces is small, reflection loss is reduced, and a bright display can be obtained.
[0019]
In the case of this embodiment, a rod mirror (RI) is arranged by arranging a first mirror (M1) having a relay lens function between the exit end face (t2) of the rod integrator (RI) and the illumination system pupil (SL). The power of the first mirror (M1) is set so that the incident end face (t1) and the illumination system pupil (SL) are conjugate. In addition, a third mirror (M3) having a condenser lens function is arranged between the illumination system pupil (SL) and the display panel (PA), and is positioned closer to the display panel (PA) side than the projection system pupil (SP). In addition to the fourth mirror (M4), the power of the third mirror (M3) is set so that the illumination system pupil (SL) and the projection system pupil (SP) are conjugate. At the same time, the first mirror (M1) having a relay lens function and the third mirror (M3) having a condenser lens function are used for the exit end surface (t2) of the rod integrator (RI) and the panel surface of the display panel (PA). Is set to be conjugate. According to this configuration, light emitted from the exit end face (t2) of the rod integrator (RI) is efficiently guided to a small display panel (PA), and the reflected light from the panel surface is projected into the projection optical system (PL). Can be efficiently led to. Therefore, it is possible to reduce the decrease in illuminance while maintaining high optical performance in the illumination optical system, and it is possible to achieve cost reduction and compactness of the display device.
[0020]
Further, between the first and third mirrors (M1, M3) having the concave reflecting surface, the second mirror (M2) having the planar reflecting surface is connected to the optical axis direction of the rod integrator (RI) and the display panel (PA). The optical path is bent so that the normal direction of the panel surface substantially coincides. In this way, the optical axis direction of the rod integrator (RI) and the normal direction of the panel surface of the display panel (PA) substantially coincide, or the optical axis of the rod integrator (RI) and the projection optical system (PL) It is desirable to have a plane reflecting surface between the two concave reflecting surfaces so that the optical axis of the first reflecting surface and the second reflecting surface are substantially parallel to each other. By bending the optical path between the first and third mirrors (M1, M3), the optical configuration of the entire display device can be made compact, and errors can be reduced by using a common design reference axis, and position adjustment can be simplified. And securing the degree of freedom of layout. Moreover, it is preferable to integrate the two concave reflecting surfaces into one component by integrating the first and third mirrors (M1, M3) into one component, thereby reducing the number of components, reducing errors and accuracy. It becomes possible to achieve the improvement.
[0021]
The concave reflecting surfaces provided on the first and third mirrors (M1, M3) are all free-form surfaces. When the illumination optical system is configured only by the power of the reflecting surface as in this embodiment, if at least one of them is a free-form surface, the illumination efficiency can be improved accordingly. For example, when a digital micromirror device is used as a display panel (PA), it is essential to obliquely illuminate the panel surface, but if a free-form surface is used, aberrations such as distortion can be corrected well even when obliquely illuminating. it can. Thereby, light can be efficiently guided toward the entrance pupil (SP) of the projection optical system (PL) to brighten the display. In other words, the imaging performance (e.g. blur and distortion) on the display panel (PA) conjugate to the exit end face (t2) of the rod integrator (RI) can be improved, so the reflected light on the display panel (PA) Can be efficiently collected on the entrance pupil (SP) of the projection optical system (PL) to increase the illumination efficiency. Further, since the change in illuminance due to the position in the screen can be reduced, it is possible to reduce unevenness in brightness.
[0022]
In this embodiment, the concave reflecting surfaces of the first and third mirrors (M1, M3) have a free-form surface. The concave reflecting surface closest to the display panel (PA) and the exit end surface of the rod integrator (RI) This is because making the concave reflection surface closest to (t2) into a free-form surface is effective in achieving the improvement in illumination efficiency and the reduction in brightness unevenness. When a digital micromirror device is used as the display panel (PA), if the concave reflective surface closest to the display panel (PA) is a free-form surface, the illumination light reflected by the micromirror in the ON state can be projected efficiently. (SP). Therefore, it is possible to effectively achieve improvement in illumination efficiency and reduction in brightness unevenness. In addition, if the concave reflecting surface closest to the exit end surface (t2) of the rod integrator (RI) is made into a free-form surface, the aberration correction when the exit end surface (t2) is imaged on the display panel (PA) will be improved. It becomes possible. Thereby, it is possible to more effectively achieve an improvement in illumination efficiency by reducing distortion and blurring.
[0023]
Further, if the vertical direction of the panel surface of the display panel (PA) is the y-axis direction and the horizontal direction is the z-axis direction, the concave reflecting surfaces of the first and third mirrors (M1, M3) are both in the y-axis direction. Each has a free-form surface that is asymmetric with respect to the z-axis direction. Thus, it is desirable that at least one of the concave reflecting surfaces constituting the reflecting optical system has a free curved surface shape that is asymmetric in the y-axis direction and the z-axis direction. By doing so, it becomes easier to control the reflection direction of the light beam depending on the position where it hits the concave reflecting surface, so that the optical performance of image formation and distortion can be improved. In the case of the present embodiment, as can be seen from FIGS. 3 and 4, the object plane {the exit end surface (t2) of the rod integrator (RI)} and the image plane {the panel surface of the display panel (PA)} are mainly used. It increases in the z-axis direction, and the free-form surface of each concave reflecting surface is also optimized with a shape that reflects its layout.
[0024]
Furthermore, a ray that passes through the display panel (PA) from the center of the exit end surface (t2) of the rod integrator (RI) and reaches the center of the entrance pupil (SP) of the projection optical system (PL) is a concave reflecting surface having a free-form surface. It is desirable that the concave reflecting surface having a free curved surface shape satisfies the following conditional expression (i), and the free curved surface shape does not have surface symmetry with respect to the radius of curvature at the point of contact. According to this configuration, it is possible to improve optical performance, reduce distortion, and improve imaging performance. As a result, it becomes possible to improve illumination efficiency.
| CRy | <| CRz |… (i)
However,
CRz: radius of curvature cut by a plane including the incident light beam and the outgoing light beam on the concave reflecting surface having a free-form surface shape,
CRy: a radius of curvature that is perpendicular to the plane that includes the incident and exit rays on the concave reflecting surface having a free-form surface, and that is cut by the plane that includes the normal vector of the concave reflecting surface;
It is.
[0025]
As a substrate material constituting the reflecting surface of each mirror (M1 to M8), any material such as glass, plastic, metal, ceramic, etc. may be used, and what is necessary may be used. For example, in order to prevent deterioration in imaging performance due to temperature change, a material such as glass having a small shape change is preferable, and in order to reduce cost, a plastic material such as PMMA (polymethyl methacrylate) or PC (polycarbonate) is preferable. In order to increase the illumination efficiency, it is necessary to apply a highly reflective coating on the substrate. Specifically, a metal reflective thin film such as Al (aluminum) or Ag (silver) is formed, or a dielectric coating is applied. A reflective film may be formed. A multilayer film made of several tens of dielectric layers may be coated. In that case, unlike the metal film, there is no light absorption by the metal, which is preferable because there is no problem that the absorbed light is changed to heat even during use. Moreover, it is preferable that the reflectance of the reflective surface with visible light is approximately 90% or more.
[0026]
【Example】
Next, the optical configuration of the illumination optical system described above will be described more specifically with reference to construction data and the like. In the following construction data, in the system including from the end surface (t2) of the rod integrator (RI) to the panel surface of the display panel (PA), the arrangement, surface shape, etc. of each optical element in order from the light source (L1) side. Optical data is shown. The arrangement of each optical element is the local Cartesian coordinates in the global Cartesian coordinate system (X, Y, Z), with the surface vertex of the optical surface as the origin (o) of the local Cartesian coordinate system (x, y, z). It is expressed by the coordinate data (X, Y, Z) of the origin (o) of the system (x, y, z) and the coordinate axis vector (vx, vy) of the x and y axes (unit: mm). Further, a coaxial optical element composed of two or more optical surfaces is represented by an axial upper surface distance (T ′, mm) with respect to the incident-side optical surface. Therefore, the direction of the rotationally symmetric axis in the coaxial block is expressed by the coordinate data (X, Y, Z) of the surface normal vector (vx) at the origin (o).
[0027]
The surface shape of each optical element is the curvature of the optical surface (C0, mm^-1In the case of a free-form surface, it is defined by the following extended aspherical expression (FS) using a local Cartesian coordinate system (x, y, z) whose origin is the surface vertex (o) . Also, the refractive index (N) for the d-line of the medium located on the incident side of each optical surface, the refractive index (N ') for the d-line of the medium located on the exit side, and the Abbe number (νd) of the optical material are combined. The effective radius (R) of the optical surface is also indicated if necessary.
[0028]
x = (C0 ・ h²) / {1 + √ (1-ε ・ C0²・ H²)} + Σ {G (j, k) ・ y^j・ Z^k}… (FS)
However, in the formula (FS)
x: Amount of displacement from the reference plane in the x-axis direction at the position of height h (plane vertex reference),
h: Height in the direction perpendicular to the x-axis (h²= y²+ z²),
C0: curvature at the surface vertex (positive or negative is with respect to the x-axis, and if positive, the center of curvature exists in the positive direction on the vector vx),
ε: quadric surface parameter,
G (j, k): j-th order of y, k-th order extended aspheric coefficient of z (the coefficient of the term not described is 0),
It is.
[0029]
<Injection end face (t2) of rod integrator (RI)>
Rod size (hollow): 3.9mm (length) x 6.7mm (width) x 35mm (length)
o :( -14.02584, 12.00438, -76.96887)
vx: (-1.00000000, 0.00000000, 0.00000000)
vy :( 0.00000000, -0.99838995, -0.05672304)
N = 1.00000
C0 = 0.00000000
N '= 1.00000
[0030]
<Concave reflecting surface of the first mirror (M1)>
o :( -46.47675, 12.00438, -76.96887)
vx: (-1.00000000, 0.00000000, 0.00000000)
vy :( 0.00000000, -0.99838995, -0.05672304)
N = 1.00000
C0 = 0.00000000
ε = 1.00000000
G (1,0) = 0.000306699905
G (2,0) =-0.00908106398
G (3,0) =-8.07892955 × 10^-7
G (4,0) =-1.98717695 × 10^-6
G (5,0) = 1.08512241 × 10^-8
G (6,0) = 5.58684963 × 10^-9
G (7,0) =-3.34949549 × 10^-11
G (8,0) =-4.91483340 × 10^-12
G (0,1) = 0.329970530
G (1,1) = 0.000231084778
G (2,1) = 0.000105566790
G (3,1) =-6.04445485 × 10^-8
G (4,1) = 1.65959977 × 10^-7
G (5,1) = 1.77506594 × 10^-9
G (6,1) =-5.46257539 × 10^-Ten
G (7,1) = 1.22613569 × 10^-12
G (0,2) =-0.00914828809
G (1,2) =-3.36307029 × 10^-6
G (2,2) =-3.79663012 × 10^-6
G (3,2) = 5.24678841 × 10^-8
G (4,2) = 2.92382569 × 10^-9
G (5,2) =-2.62911765 × 10^-Ten
G (6,2) = 4.72402181 × 10^-12
G (0,3) = 8.05884647 × 10^-Five
G (1,3) = 8.31497717 × 10^-8
G (2,3) =-8.33084401 × 10^-8
G (3,3) =-2.32070916 × 10^-9
G (4,3) = 3.34976119 × 10^-Ten
G (5,3) = 9.96252911 × 10^-12
G (0,4) =-2.36232594 × 10^-6
G (1,4) = 3.33590529 × 10^-8
G (2,4) = 4.93651852 × 10^-9
G (3,4) =-2.69043165 × 10^-11
G (4,4) =-2.72594071 × 10^-11
G (0,5) = 9.08689438 × 10^-8
G (1,5) =-8.86313676 × 10^-Ten
G (2,5) = 1.71838290 × 10^-Ten
G (3,5) = 2.57328687 × 10^-12
G (0,6) =-2.79012040 × 10^-Ten
G (1,6) =-7.54028329 × 10^-11
G (2,6) =-6.20207234 × 10^-12
G (0,7) =-1.08926425 × 10^-Ten
G (1,7) = 2.60400479 × 10^-12
G (0,8) = 2.15734871 × 10^-12
N '=-1.00000
[0031]
<Planar reflecting surface of the second mirror (M2)>
o :( -10.00000, 10.44701, -50.00000)
vx :( 0.94507308, 0.30159769, -0.12599885)
vy :( 0.29066098, -0.95178425, -0.09809659)
N = 1.00000
C0 = 0.00000000
N '=-1.00000
[0032]
<Lighting system pupil (SL)>
o :( -21.12051, 0.11765, -32.15182)
vx: (-0.48205523, -0.44754084, 0.75321309)
vy :( 0.21295825, -0.89376373, -0.39475965)
N = 1.00000
C0 = 0.00000000 (R = 15)
N '= 1.00000
[0033]
<Concave reflective surface of the third mirror (M3)>
o :( -50.00020, -27.01956, 14.90964)
vx: (-0.70351808, -0.46400538, 0.53829483)
vy :( 0.33768245, -0.88472575, -0.32129566)
N = 1.00000
C0 = 0.00000000
ε = 1.00000000
G (1,0) =-0.0165717437
G (2,0) =-0.00358908679
G (3,0) =-2.96168772 × 10^-6
G (4,0) =-8.41908290 × 10^-7
G (5,0) = 1.09778063 × 10^-7
G (6,0) = 5.62907582 × 10^-9
G (7,0) =-3.56648227 × 10^-Ten
G (8,0) =-1.75864361 × 10^-11
G (0,1) =-0.00730596825
G (1,1) =-0.000573447332
G (2,1) =-2.26990751 × 10^-Five
G (3,1) =-5.87353269 × 10^-7
G (4,1) =-4.21148102 × 10^-9
G (5,1) = 3.90388810 × 10^-9
G (6,1) =-8.27699273 × 10^-11
G (7,1) =-1.20079976 × 10^-11
G (0,2) =-0.00318395834
G (1,2) = 9.26292117 × 10^-7
G (2,2) =-8.57133481 × 10^-7
G (3,2) =-1.15650143 × 10^-7
G (4,2) =-3.34437629 × 10^-9
G (5,2) = 4.84297082 × 10^-Ten
G (6,2) = 2.47858612 × 10^-11
G (0,3) =-1.26500601 × 10^-Five
G (1,3) = 4.53962253 × 10^-7
G (2,3) =-5.34439218 × 10^-9
G (3,3) = 2.07178981 × 10^-9
G (4,3) = 5.26613238 × 10^-Ten
G (5,3) = 2.04221150 × 10^-11
G (0,4) =-6.68600297 × 10^-7
G (1,4) =-7.24724659 × 10^-9
G (2,4) = 5.29717438 × 10^-9
G (3,4) =-1.84848215 × 10^-11
G (4,4) = 7.58382766 × 10^-12
G (0,5) = 9.43218162 × 10^-9
G (1,5) =-1.74670419 × 10^-9
G (2,5) =-6.08190477 × 10^-11
G (3,5) =-1.88709489 × 10^-11
G (0,6) = 1.34128868 × 10^-9
G (1,6) = 1.25465294 × 10^-11
G (2,6) =-1.36776768 × 10^-11
G (0,7) =-1.22396504 × 10^-12
G (1,7) = 1.49699829 × 10^-12
G (0,8) =-5.01105893 × 10^-13
N '=-1.00000
[0034]
<Protective glass for display panel (PA)>
o :( -3.47000, 0.00000, 0.00000)
vx :( 1.00000000, 0.00000000, 0.00000000)
vy :( 0.00000000, -0.99838995, -0.05672304)
(Incident side)
N = 1.00000
C0 = 0.00000000
N '= 1.51872 (νd = 64.20)
T '= 3
(Ejection side)
N = 1.51872 (νd = 64.20)
C0 = 0.00000000
N '= 1.00000
[0035]
<Display panel (PA) panel surface>
Panel size: 10.3mm (vertical) x 17.6mm (horizontal)
o :( 0.00000, 0.00000, 0.00000)
vx :( 1.00000000, 0.00000000, 0.00000000)
vy :( 0.00000000, 1.00000000, 0.00000000)
N = 1.00000
C0 = 0.00000000
N '= 1.00000
[0036]
FIG. 6 shows the free curved surface shape of the concave reflecting surface of the first mirror (M1), and FIG. 7 shows the free curved surface shape of the concave reflecting surface of the third mirror (M3). The graphs of FIGS. 6 and 7 are obtained by plotting the free-form surface shape of each concave reflecting surface by selecting a spherical surface having a radius of curvature that minimizes the amount of displacement from the reference spherical surface. In FIG. The amount of displacement from a spherical surface with a radius of -187.03 mm is shown with a 0.75 mm pitch, and in FIG. 7, the amount of displacement from a spherical surface with a radius of curvature of -68.96 mm is shown with a pitch of 0.25 mm. In each graph, a portion with a sign of-represents a concave surface, and a portion with a sign of + represents a convex surface. FIG. 8 shows a reflection state of illumination light on the panel surface of the display panel (PA). A zebra pattern portion is an area on the panel surface of the digital micromirror device. }, FIG. 9 shows the illuminance distribution on the panel surface of the display panel (PA), and FIG. 10 shows the illuminance distribution on the screen (SC).
[0037]
Here, the asymmetry of the free-form surface will be specifically described. Ejected from the center of the exit surface (t2) of the rod integrator (RI), which is the object plane, passes through the approximate center of the illumination system pupil (SL), and reaches the center of the panel surface of the display panel (PA), which is the image plane. If the ray is the principal ray, in this embodiment, the position on each surface through which the principal ray passes is designed to pass near the origin (o) of the local coordinates (x, y, z) of each surface. Yes. Accordingly, the radii of curvature CRy and CRz near the origin (o) of each free-form surface in each of the y-axis and z-axis directions are as follows.
First mirror (M1)… CRy = -55.06, CRz = -63.82
3rd mirror (M3)… CRy = -139.37, CRz = -157.05
[0038]
Since both are free-form surfaces, the radius of curvature differs between the y-axis direction and the z-axis direction, but the curvature radius (absolute value) in the y-axis direction is clearly smaller than the eccentric direction (z-axis direction). I understand that. Therefore, it can be said that the following formula (I) is established at the position where the principal ray passing through the center of the illumination system pupil (SL) from the center of the object plane (t2) passes through each surface.
| The radius of curvature in the direction of eccentricity |> | the radius of curvature in the direction perpendicular to the direction of eccentricity | ... (I).
[0039]
Strictly speaking, it passes through the center of the illumination system pupil (SL) from a point slightly shifted in the vertical direction (i.e., the y-axis direction) from the center of the object plane (t2), and passes through the center of the illumination system pupil (SL). If the position where the ray reaching the panel surface} passes through each surface is Py, and the position where the principal ray passes through each surface is P0, the y-axis direction of the local coordinate system of each surface is defined as the normal of that surface. The direction of the vector projected from the point P0 to the point Py projected onto the plane perpendicular to the vector (the z-axis direction is obtained from the normal vector and the y-axis vector), and the lateral direction of the image plane (image plane coordinates = global coordinates) If the optical system is mainly decentered in the Z-axis direction in the system, it can be said that the following equation (II) holds.
| Curvature radius of each local coordinate system in the y-axis direction | <| Curvature radius of each local coordinate system in the z-axis direction |… (II)
[0040]
In the present embodiment, in a plane including the y-axis direction vector of image plane coordinates (= global coordinate system) and the normal vector of local coordinates of each plane, a vector perpendicular to the normal vector is defined as the local coordinates of each plane. Although the y-axis direction of the system is used, conditional expression (II) may be used when taking the y-axis direction of the local coordinate system as described above. Alternatively, the normal vector of the surface is taken in the direction in which the incident ray travels on the bisector of the angle of the two rays of the incident ray and the outgoing ray when the principal ray passes through each surface, The y-axis direction of the local coordinate system is perpendicular to the normal vector and perpendicular to the plane containing the incident and outgoing rays, and the z-axis direction is perpendicular to the normal vector and the y-axis vector. It is preferable to configure the optical system so that the relationship of the conditional expression (II) is satisfied between the respective curvature radii in the y-axis direction and the z-axis direction.
[0041]
【The invention's effect】
As described above, according to the present invention, the reflecting optical system has only the first and second concave reflecting surfaces as the optical surfaces having power, and the secondary light source is changed from the secondary light source to the first concave reflecting surface. The projection-type display device is configured to efficiently guide the light from the tertiary light source to the entrance pupil of the projection optical system by the second concave reflecting surface, while maintaining high optical performance in the illumination optical system. The cost can be reduced and the size can be reduced. Furthermore, if a free-form concave reflecting surface having asymmetry is used, it is possible to effectively improve illumination efficiency and reduce brightness unevenness, and between the first and second concave reflecting surfaces. If a plane reflecting surface is provided, the optical configuration of the entire display device can be made compact.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the entire system of a projection display apparatus according to the present invention.
FIG. 2 is a perspective view showing a schematic configuration of a main part of a projection display device according to the present invention.
FIG. 3 is a bottom view showing a schematic configuration of a main part of a projection display device according to the present invention.
FIG. 4 is a side view showing a schematic configuration of a main part of a projection display device according to the present invention.
FIG. 5 is an optical configuration diagram showing a main part of an optical engine unit in the display device of FIGS.
6 is a graph showing the shape of a free-form curved reflecting surface of a first mirror used in the illumination optical system in the display device of FIGS.
7 is a graph showing the shape of a free-form curved reflecting surface of a third mirror used in the illumination optical system in the display device of FIGS.
FIG. 8 is a diagram showing a reflected state of illumination light on the display panel surface in the display device of FIGS.
9 is a diagram showing an illuminance distribution on the display panel surface in the display device of FIGS. 1 to 4; FIG.
10 is a diagram showing an illuminance distribution on a screen surface in the display device of FIGS. 1 to 4; FIG.
[Explanation of symbols]
OP: Optical engine
LA ... Light source lamp
L1 ... Light source
L2 ... Elliptic reflector (condensing optical system)
RI… Rod integrator
t1 ... Incident end face
t2 ... Injection end face
CW ... Color wheel (color filter)
M1 ... first mirror (first concave reflecting surface, reflecting optical system)
M2 ... Second mirror (planar reflecting surface, reflecting optical system)
M3 ... Third mirror (second concave reflecting surface, reflecting optical system)
M4 to M8 ... 4th to 8th mirrors (projection optical system)
PL ... Projection optical system
SL… Lighting system pupil
SP ... projection system pupil
PA: Display panel
SC ... screen

Claims (4)

A projection display device that guides light from a light source to a display panel with an illumination optical system, and projects a display image of the display panel illuminated thereby on a screen with a projection optical system,
A condensing optical system for condensing light from the light source to form a secondary light source, and a spatial energy distribution of the light collected by the condensing optical system having an incident end face near the secondary light source Light intensity uniformizing means for uniforming the light intensity, a color filter for changing the emitted light color in a time-division manner for color display in the vicinity of the incident end face or the exit end face of the light intensity uniformizing means, and the light intensity uniformizing means A reflection optical system that forms an image of the emission end face of the display panel on the panel surface of the display panel, and the illumination optical system,
The display panel is a reflective type, the illumination optical system illuminates the panel surface of the display panel from an oblique direction, and the projection optical system is oblique telecentric on the display panel side,
The reflective optical system has only first and second concave reflective surfaces as optical surfaces having power, and a tertiary light source is formed from the secondary light source by the first concave reflective surface, and the second concave surface -out guide the light from the tertiary light sources in the entrance pupil of the projection optical system by the reflection surface,
When the vertical direction of the panel surface of the display panel is the y- axis direction and the horizontal direction is the z- axis direction, at least one of the first and second concave reflecting surfaces is in the y- axis direction and the z- axis direction, respectively. It has an asymmetric free-form surface shape,
With respect to the radius of curvature at the point where a light beam that passes through the display panel from the center of the exit end face of the light intensity uniformizing means and reaches the center of the entrance pupil of the projection optical system hits the concave reflecting surface of the free-form curved surface, A projection display device characterized in that a concave reflecting surface having a curved surface satisfies the relationship of the following conditional expression (i) , and the free curved surface has no surface symmetry ;
| CRy | < | CRz | … (i)
However,
CRz : radius of curvature cut by a plane including incident light and outgoing light to a concave reflecting surface having a free-form surface,
CRy : a radius of curvature that is perpendicular to the plane that includes the incident and exit rays on the concave reflecting surface having a free-form surface, and that is cut by the plane that includes the normal vector of the concave reflecting surface;
It is . Further, the optical axis of the light intensity uniformizing means and the optical axis of the projection optical system are substantially parallel, or the optical axis direction of the light intensity uniformizing means and the normal direction of the panel surface of the display panel 2. The projection display device according to claim 1, further comprising a plane reflecting surface between the first concave reflecting surface and the second concave reflecting surface so that the two substantially coincide with each other . A projection display device that guides light from a light source to a display panel with an illumination optical system, and projects a display image of the display panel illuminated thereby on a screen with a projection optical system,
A condensing optical system for condensing light from the light source to form a secondary light source, and a spatial energy distribution of the light collected by the condensing optical system having an incident end face near the secondary light source Light intensity uniformizing means for uniforming the light intensity, a color filter for changing the emitted light color in a time-division manner for color display in the vicinity of the incident end face or the exit end face of the light intensity uniformizing means, and the light intensity uniformizing means A reflection optical system that forms an image of the emission end face of the display panel on the panel surface of the display panel, and the illumination optical system,
The display panel is a reflective type, and the illumination optical system performs illumination from an oblique direction with respect to the panel surface of the display panel,
The reflecting optical system has only the first and second concave reflecting surfaces as the optical surfaces having power, and the optical axis of the light intensity uniformizing means and the optical axis of the projection optical system are substantially parallel. Or the optical axis direction of the light intensity equalizing means and the normal direction of the panel surface of the display panel substantially coincide with each other between the first concave reflective surface and the second concave reflective surface. The projection light system has a plane reflection surface in between, the tertiary light source is formed from the secondary light source by the first concave reflection surface, and the light from the tertiary light source is transmitted by the second concave reflection surface of the projection optical system. Led to the entrance pupil,
When the vertical direction of the panel surface of the display panel is the y- axis direction and the horizontal direction is the z- axis direction , at least one of the first and second concave reflecting surfaces is in the y- axis direction and the z- axis direction, respectively. It has an asymmetric free-form surface shape,
With respect to the radius of curvature at the point where a light beam that passes through the display panel from the center of the exit end face of the light intensity uniformizing means and reaches the center of the entrance pupil of the projection optical system hits the concave reflecting surface of the free-form curved surface, concave reflecting surface satisfies the relation of the following conditional expressions (i), the free-form surface is projected shadow type display device you characterized by not having a plane symmetry with a curved surface shape;
| CRy | <| CRz |… (i)
However,
CRz: radius of curvature cut by a plane including incident and exiting rays on a concave reflecting surface having a free-form surface,
CRy: a radius of curvature that is perpendicular to the plane that includes the incident and exit rays on the concave reflecting surface having a free-form surface, and that is cut by the plane that includes the normal vector of the concave reflecting surface;
It is. 4. The projection display device according to claim 2 , wherein each of the first and second concave reflecting surfaces has an asymmetric free-form surface shape in the y- axis direction and the z- axis direction .

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