JP2001110217A - Lighting system and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting system with high lighting efficiency and a projector with a bright projecting image. SOLUTION: A reflecting plane of a reflector 3 is formed by using a straight line B as a rotational axis AX between a point A a distance Δapart from a first focal point F of an ellipse to a short axis and a second focal point for rotating an elliptical curve on the side of not including the first focal point F out of the ellipse divided by the rotational axis AX. A light source 1 is located on the point A and a bulb 2 is a optical system which is rotationally symmetrical with the rotational axis AX and has an optical axis ax passing through the point A in a plane including the rotational axis AX. Conditional expressions 0<L<f, L2/ 2.(f-L)}<=Δ<=3. L2/ 2.(f-L)} are satisfied where f is a focal distance of the bulb 2 and L is a distance from the rotational axis AX to a main point of the bulb 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device and a projection device using the same, for example, a display device.
(A liquid crystal panel, etc.), and a projection device (a liquid crystal projector, etc.) for projecting the display image on a screen
It is about.

[0002]

2. Description of the Related Art To obtain a bright image with a projection device,
It is necessary to increase the utilization efficiency of light for illuminating the display element (that is, illumination efficiency). Various illumination devices have been proposed to achieve this. For example, Patent 2836788
Japanese Patent Laid-Open Publication No. HEI 9-175686 proposes an illumination device in which a reflector having a circular focal line is used and electrodes (bright points) are arranged before and after a surface formed by the focal line. In this illuminator, the reflecting surface of the reflector is composed of a paraboloid that is offset to the outside to improve the illumination efficiency, but the optical action of the bulb that constitutes the lamp is taken into consideration. It has not been.

[0003]

In recent years, an ultra-high pressure mercury lamp capable of obtaining a short arc of about 1 mm has been used as a lamp for a liquid crystal projector. In this lamp, the optical action of the bulb is greater than before. Since a liquid crystal projector is required to provide uniform illumination using an integrator (for example, a kaleidoscope or two lens arrays), if the optical action of the bulb is large, the illumination efficiency will decrease.

[0004] For example, when an elliptical reflector and a kaleidoscope are combined, the degree of light collection of the light source image by the elliptical reflector becomes poor, and the efficiency of incidence on the kaleidoscope is reduced. When a parabolic reflector and two lens arrays are combined, the distribution of the light source image formed on one of the lens arrays is shifted.
In other words, even if the light source is arranged at the focal position of the reflection surface (elliptical surface, paraboloid), an optical deviation occurs at the light source position due to the optical action of the bulb (that is, the optical system composed of the reflection surface and the bulb). Is different from the focal position of only the reflecting surface), the illumination efficiency is reduced.

[0005] The present invention has been made in view of such circumstances, and a first object of the present invention is to provide a lighting device capable of achieving high lighting efficiency. It is a second object of the present invention to provide a projection device capable of obtaining a bright projection image.

[0006]

In order to achieve the first object, a lighting device according to a first aspect of the present invention includes a light source that emits illumination light, a transparent member that transmits the illumination light from the light source,
A reflector configured to rotate the part of the elliptic curve or the part of the parabola, and a reflector configured to reflect the illumination light having passed through the transparent member; The point (A) separated from the first focal point of the ellipse by a distance Δ in the minor axis direction of the ellipse and the second point (A)
With the straight line (B) connecting the focal point as the rotation axis, the ellipse divided by the rotation axis is formed by rotating an elliptic curve located on the side not including the first focal point, and a part of the parabola is formed. The point at which the rotating reflecting surface is separated from the focal point of the parabola by a distance Δ in the direction perpendicular to the symmetry axis of the parabola
(A), and formed by rotating a parabola located on the side not including the focal point among the parabolas divided by the rotation axis, using a straight line (B) parallel to the symmetry axis as a rotation axis. An optical system in which the light source is located at the point (A), the transparent member is rotationally symmetric with respect to the rotation axis, and the optical axis passes through the point (A) in a plane including the rotation axis. And satisfy the following conditional expressions (i) and (ii). 0 <L <f ... (i ) L 2 / {2 · (f-L)} ≦ Δ ≦ 3 · L 2 / {2 · (f-L)} ... (ii) however, f: the focal point of the transparent member Distance, L: Distance from the rotation axis to the principal point of the transparent member.

To achieve the first object, a lighting device according to a second aspect of the present invention includes a light source for emitting illumination light, a transparent member for transmitting the illumination light from the light source, a part of an elliptic curve or a parabola. A reflector for reflecting the illumination light transmitted through the transparent member on a reflecting surface formed by rotating a part of the elliptic curve, wherein the reflector is formed by rotating a part of the elliptic curve. A straight line connecting the point (A) whose surface is separated from the first focal point of the ellipse by a distance Δ in the minor axis direction of the ellipse and the second focal point
A reflection surface formed by rotating an elliptic curve positioned on the side including the first focal point in an ellipse divided by the rotation axis with (B) as a rotation axis, and rotating a part of the parabola. Is a point passing through a point (A) away from the focal point of the parabola in a direction perpendicular to the axis of symmetry of the parabola (A), and a straight line (B) parallel to the axis of symmetry as a rotation axis, and is divided by the rotation axis. The parabola is formed by rotating a parabola located on the side including the focal point, the light source is located at the point (A), and the transparent member is rotationally symmetric with respect to the rotation axis, An optical system in which the optical axis passes through the point (A) in a plane including the rotation axis, and satisfies the following conditional expressions (iii) and (v) or conditional expressions (iv) and (v). I do. f <0 ... (iii) 0 <f <L ... (iv) L 2 / {2 · (L-f)} ≦ Δ ≦ 3 · L 2 / {2 · (L-f)} ... (v) except F: focal length of the transparent member; L: distance from the rotation axis to the principal point of the transparent member.

In order to achieve the first object, a lighting device according to a third aspect of the present invention is the illumination device according to the first or second aspect of the present invention, further comprising a uniform illumination distribution of illumination light from the lamp. An integrator is provided, and the integrator comprises two lens arrays or a kaleidoscope.

In order to achieve the second object, a projection device according to a fourth aspect of the present invention includes a lighting device according to the first, second, or third aspect, and a display for modulating illumination light from the illumination device. And a projection optical system that projects light modulated by the display element.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an illumination device and a projection device embodying the present invention will be described with reference to the drawings. First, the reflection surface of the reflector constituting the lighting device will be described. The reflecting surface of the reflector is divided into four types shown in FIGS. The reflection surface shown in FIGS. 1 and 2 is a reflection surface obtained by rotating a part (E1, E2) of the elliptic curve (E).
Is a reflection surface obtained by rotating a part (P1, P2) of the parabola (P).

The reflecting surface shown in FIGS. 1 and 2 has a surface structure formed as follows. First, the long axis (L),
An ellipse (E) with a short axis (S) is assumed. In FIG. 1, the reflection surface indicated by a thick solid line is a point (A) separated from the first focus (F1) of the ellipse (E) in the direction of the short axis (S) of the ellipse (E) by a point (A) and a second focus (F2). The ellipse curve (E1) located on the side not including the first focal point (F1) of the ellipse (E) divided by the rotation axis (AX) with the straight line (B) connecting It is formed by rotating.
On the other hand, the reflection surface indicated by the thick solid line in FIG.
A straight line (B) connecting the point (A) separated by a distance Δ in the direction of the short axis (S) of the ellipse (E) from the first focal point (F1) and the second focal point (F2) as a rotation axis (AX), The first of the ellipses (E) divided by the rotation axis (AX)
It is formed by rotating the elliptic curve (E2) located on the side including the focal point (F1).

The reflecting surface shown in FIGS. 3 and 4 has a surface structure formed as follows. In FIG. 3, the reflection surface shown by the thick solid line is the parabola from the focus (F) of the parabola (P).
A point at a distance Δ away from the symmetry axis (AX0) of (P) in the vertical direction
A parabola (P) divided by the rotation axis (AX) with the straight line (B) passing through (A) and parallel to the symmetry axis (AX0) as the rotation axis (AX)
Is formed by rotating a parabola (P1) located on the side not including the focal point (F). On the other hand, the reflection surface shown by the thick solid line in FIG. 4 is a point that is away from the focal point (F) of the parabola (P) by a distance Δ in the direction perpendicular to the symmetry axis (AX0) of the parabola (P).
A parabola (P) divided by the rotation axis (AX) with the straight line (B) passing through (A) and parallel to the symmetry axis (AX0) as the rotation axis (AX)
Of the parabola (P2) located on the side including the focal point (F).

Next, the lighting device will be described. The illuminating device according to the present invention includes a lamp including a light source (1), a bulb (2), and a reflector (3), as shown in FIGS.
The light source (1) that emits illumination light is located at the point (A), and the illumination light from the light source (1) passes through the bulb (2) and is reflected by the reflector (3). The bulb (2) is a transparent member made of a hollow sphere such as quartz, is rotationally symmetric with respect to the rotation axis (AX, B), and has an optical axis (in a plane including the rotation axis (AX, B)). ax) is the optical system passing through the point (A). Also the valve
Since the principal point of (2) is located at a distance L from the rotation axis (AX, B), the optical axis of the bulb (2) is rotationally symmetric with respect to the rotation axis (AX, B).
(ax) is located on a plane perpendicular to the rotation axis (AX, B).

The reflector (3) is a part of the elliptic curve (E).
It has a reflection surface (FIGS. 1 and 2) obtained by rotating (E1, E2). However, the focal point (F) in FIGS. 5 to 7 corresponds to the first focal point (F1) in FIGS. The illumination light transmitted through the bulb (2) is collected by being reflected by the reflecting surface of the reflector (3). The parabola (P) shown in FIG. 3 and the like are obtained when the interval between the first and second focal points (F1, F2) is ∞ in the ellipse (E) shown in FIG. 1 and the like {that is, the straight line (B) and the long axis (L) Is parallel to}. Therefore, the reflecting surface (FIGS. 1 and 2) of the reflector (3) described below is a reflecting surface (FIGS. 3 and 4) obtained by rotating a part (P1, P2) of the parabola (P). There may be. In the embodiment shown in FIGS. 5 to 7, the focus (F) of the reflector (3) and the bulb (2) are in a plane including the rotation axis (AX, B).
Although the optical axis (ax) and the light source (1) are arranged on the same straight line, the focus of the reflector (3) is relative to the optical axis (ax) of the bulb (2).
Even if (F) is at a shifted position, it is sufficient that the light source (1) is at an optically corresponding position.

The lamp shown in FIG. 5 uses the reflector (3) having the reflecting surface shown in FIG. The lamp satisfies the following conditional expressions (i) and (ii) in the relationship between the reflector (3) and the bulb (2) as a transparent member. 0 <L <f ... (i ) L 2 / {2 · (f-L)} ≦ Δ ≦ 3 · L 2 / {2 · (f-L)} ... (ii) however, f: Valve (2) L: distance from the rotation axis (AX, B) to the principal point of the valve (2).

As can be seen from FIG. 5, the light beam emitted from the light source (1) is emitted from the focal point (F) of the reflector (3) by the action (0 <f) of the convex lens of the bulb (2). Proceed as if. That is, a virtual image of the light source (1) is formed at the focus (F) position. Therefore, when the conditional expression (i) is satisfied, the following expression is obtained from the paraxial relation, and the following expression 'is obtained by modifying the expression. (1 / L)-{1 / (L + Δ)} = 1 / f... Δ = L ² / (f−L).

If the optimum distance Δ is within the range of 0.5 Δ to 1.5 Δ, a sufficient effect can be obtained. Therefore, it is desirable to satisfy the conditional expression (ii) on the assumption that the conditional expression (i) is satisfied. . Outside the range of conditional expression (ii), the degree of convergence of the illumination light beam from the reflector (3) becomes poor. For example, when a kaleidoscope is used as an integrator, the light source image condensing degree by the reflector (3) becomes poor, and the efficiency of incidence on the kaleidoscope decreases. Therefore, the lighting efficiency is reduced. When the reflecting surface of the reflector (3) is a reflecting surface obtained by rotating a part (P1, P2) of the parabola (P) as shown in FIG. In addition, the parallelism of the illumination light beam from the reflector (3) deteriorates. For example, when two lens arrays are used as an integrator, the distribution of the light source image formed on one of the lens arrays shifts, and the illumination efficiency decreases.

The lamp shown in FIG. 6 uses the reflector (3) having the reflecting surface shown in FIG. The lamp satisfies the following conditional expressions (iii) and (v) in the relationship between the reflector (3) and the bulb (2) as a transparent member. f <0 ... (iii) L 2 / {2 · (L-f)} ≦ Δ ≦ 3 · L 2 / {2 · (L-f)} ... (v)

As can be seen from FIG. 6, the light beam emitted from the light source (1) is emitted from the focal point (F) of the reflector (3) by the action (f <0) of the concave lens of the bulb (2). Proceed as if. That is, a virtual image of the light source (1) is formed at the focus (F) position. Therefore, when the conditional expression (iii) is satisfied, the following expression is obtained from the paraxial relation, and the following expression 'is obtained by modifying the expression. (1 / L) − {1 / (L−Δ)} = 1 / f... Δ = L ² / (L−f).

Since a sufficient effect can be obtained if the optimum distance Δ is within the range of 0.5 Δ to 1.5 Δ, it is desirable to satisfy the conditional expression (v) on the assumption that the conditional expression (iii) is satisfied. . Outside the range of conditional expression (v), the degree of convergence of the illumination light beam from the reflector (3) will be poor. For example, when a kaleidoscope is used as an integrator, the light source image condensing degree by the reflector (3) becomes poor, and the efficiency of incidence on the kaleidoscope decreases. Therefore, the lighting efficiency is reduced. When the reflecting surface of the reflector (3) is a reflecting surface obtained by rotating a part (P1, P2) of the parabola (P) as shown in FIG. In addition, the parallelism of the illumination light beam from the reflector (3) deteriorates. For example, when two lens arrays are used as an integrator, the distribution of the light source image formed on one of the lens arrays shifts, and the illumination efficiency decreases.

In the lamp shown in FIG. 7, a reflector (3) having a reflection surface shown in FIG. 2 is used. The lamp satisfies the following conditional expressions (iv) and (v) in the relationship between the reflector (3) and the bulb (2) as a transparent member. 0 <f <L ... (iv ) L 2 / {2 · (L-f)} ≦ Δ ≦ 3 · L 2 / {2 · (L-f)} ... (v)

As can be seen from FIG. 7, the light beam emitted from the light source (1) is emitted from the focal point (F) of the reflector (3) by the action (0 <f) of the convex lens of the bulb (2). Proceed as if. That is, a real image of the light source (1) is formed at the focus (F) position. Therefore, when the conditional expression (iv) is satisfied, the following expression is obtained from the paraxial relation, and the following expression is obtained by modifying the expression. (1 / L) + {1 / (Δ−L)} = 1 / f... Δ = L ² / (L−f).

Since a sufficient effect can be obtained if the optimum distance Δ is within the range of 0.5 Δ to 1.5 Δ, it is desirable to satisfy the conditional expression (v) on the assumption that the conditional expression (iv) is satisfied. . Outside the range of conditional expression (v), the degree of convergence of the illumination light beam from the reflector (3) will be poor. For example, if a Kaleidoscope is used as an integrator, the reflector
The light source image condensing degree due to (3) is deteriorated, and the efficiency of incidence on the kaleidoscope is reduced. Therefore, the lighting efficiency is reduced. The reflecting surface of the reflector (3) is shown in FIG.
In the case of a reflecting surface formed by rotating a part (P1, P2) of the parabola (P) as shown in
The parallelism of the illumination light beam from the reflector (3) becomes poor. For example, when two lens arrays are used as an integrator, the distribution of the light source image formed on one of the lens arrays shifts, and the illumination efficiency decreases.

FIG. 8 shows an illumination device (FIG. 5) to which a kaleidoscope (4) and the like are added. Illumination light from the light source (1) passes through the bulb (2) and is reflected by the reflector (3). The illumination light reflected by the reflector (3) is collected at the position of the incident end face of the kaleidoscope (4). The kaleidoscope (4) is an integrator for uniformizing the illuminance distribution of the illumination light, and is formed of a polygonal glass body or a hollow cylindrical body formed by combining a plurality of mirrors.

The illumination light incident on the kaleidoscope (4) at various angles is totally reflected repeatedly on the side surfaces thereof, so that the spatial energy distribution (that is, the illuminance distribution) is made uniform. Then, the light is emitted as diffused light from an emission end face conjugate with the display surface of the display element (8). The illumination light emitted from the kaleidoscope (4) passes through a first condenser lens (5), two relay lenses (6), and a second condenser lens (7) to uniformly illuminate the display element (8). . The display element (8) is a light modulation element (a liquid crystal panel or the like) that modulates illumination light to project a display image, and the optical axis of an illumination optical system that guides the illumination light thereto is the rotation axis (AX). ) (The same applies to FIG. 9 described later).

With this lighting device, it is possible to achieve high lighting efficiency due to the characteristic relationship between the reflector (3), the bulb (2), and the light source (1). Even when using an ultra-high pressure mercury lamp with a shorter arc and higher luminous efficiency than a metal halide lamp, there is no adverse effect from the optical action of the bulb (2), so the kaleidoscope (4)
In this case, it is possible to prevent the lighting efficiency from being reduced when the light emitting device is used.

FIG. 9 shows an embodiment of the projection apparatus.
The projection device includes an illumination device, a display element (8) for modulating illumination light from the illumination device, and a projection optical system (11) for projecting light modulated by the display element (8). ing. The lighting device includes a light source (1), a bulb (2), and a reflector (3).
An integrator comprising a first lens array (9A) and a second lens array (9B); a superposition lens
(10); and a condenser lens (7). The reflector (3) has a reflecting surface shown in FIG.
With respect to the relationship between the reflector (3) and the bulb (2) as a transparent member, the lamp satisfies the conditional expressions (i) and (ii) described above.

The illumination light from the light source (1) passes through the bulb (2) and is reflected by the reflector (3). Reflector
The illumination light reflected by (3) enters the first lens array (9A) as parallel light. The first lens array (9A) has a conjugate relationship with the display surface of the display element (8), and forms incident parallel light on the second lens array (9B). Illumination light split by the two lens arrays (9A, 9B) exits the second lens array (9B), passes through the superimposing lens (10) and the condenser lens (7), and is displayed on the display element (8). It is superimposed on top to provide uniform illumination. Light modulated by transmission or reflection by the display element (8) enters a projection optical system (11) to form a display image on a projection surface (screen or the like).
Since high illumination efficiency is achieved by the above-described characteristic relationship among the reflector (3), the bulb (2), and the light source (1), a bright projected image can be obtained by this projection device.

[0029]

As described above, with the use of the lighting device according to the present invention, high lighting efficiency can be achieved due to the characteristic relationship between the reflector, the transparent member, and the light source. For example, even when using an ultra-high pressure mercury lamp with a short arc and a higher luminous efficiency than a metal halide lamp,
Since there is no adverse effect due to the optical action of the bulb, it is possible to prevent a decrease in illumination efficiency when the integrator is used. Therefore, according to the projection device of the present invention, a bright projected image can be obtained.

[Brief description of the drawings]

FIG. 1 is an optical configuration diagram showing one embodiment of a reflection surface formed by rotating a part of an elliptic curve.

FIG. 2 is an optical configuration diagram showing another embodiment of a reflection surface formed by rotating a part of an elliptic curve.

FIG. 3 is an optical configuration diagram showing one embodiment of a reflection surface formed by rotating a part of a parabola.

FIG. 4 is an optical configuration diagram showing another embodiment of a reflection surface formed by rotating a part of a parabola.

FIG. 5 is an optical configuration diagram showing one embodiment of a lighting device including the reflector having the reflection surface of FIG. 1;

FIG. 6 is an optical configuration diagram showing one embodiment of a lighting device including the reflector having the reflection surface of FIG. 2;

FIG. 7 is an optical configuration diagram showing another embodiment of the illumination device including the reflector having the reflection surface of FIG. 2;

FIG. 8 is an optical configuration diagram showing a state in which a kaleidoscope or the like is used in the illumination device of FIG. 5;

FIG. 9 is an optical configuration diagram showing an embodiment of a projection device provided with a reflector having the reflection surface of FIG. 3;

[Explanation of symbols]

 1… light source 2… bulb (transparent member) ax… bulb optical axis 3… reflector 4… kaleidoscope (integrator) 8… display element 9A… first lens array (integrator) 9B… second lens array (integrator) 11… Projection optical system A: Point B: Straight line AX: Rotation axis (optical axis of illumination optical system) E: Ellipse L: Long axis S: Short axis F1: First focus F2: Second focus E1: Part of elliptic curve E2 … Part of the elliptic curve P… parabolic AX0… axis of symmetry F… focus P1… part of the parabola P2… part of the parabola

Claims (4)

[Claims] 1. A light source that emits illumination light, a transparent member that transmits illumination light from the light source, and a reflection surface formed by rotating a part of an elliptic curve or a part of a parabola. A reflector comprising: a reflector configured to reflect illumination light; and a lamp configured to rotate a part of the elliptic curve, wherein a reflection surface is separated from a first focal point of the ellipse by a distance Δ in a minor axis direction of the ellipse. The straight line (B) connecting the point (A) and the second focal point is used as a rotation axis to form an ellipse divided by the rotation axis and by rotating an elliptic curve located on the side not including the first focal point. A reflection surface formed by rotating a part of the parabola passes through a point (A) away from the focal point of the parabola by a distance Δ in a direction perpendicular to the symmetry axis of the parabola, and a straight line parallel to the symmetry axis. (B) as a rotation axis, of the parabola divided by the rotation axis, The light source is located at the point (A) formed by rotating a parabola located on the side not including the focal point, and the transparent member is rotationally symmetric with respect to the rotation axis and includes the rotation axis. An illumination system in which an optical axis passes through the point (A) in the plane and satisfies the following conditional expressions (i) and (ii): 0 <L <f (i) L ² / {2 · (f−L)} ≦ Δ ≦ 3 · L ² / {2 · (f−L)} (f) where f is the focal length of the transparent member, and L is the principal of the transparent member from the rotation axis. The distance to the point. 2. A light source that emits illumination light, a transparent member that transmits illumination light from the light source, and a reflection surface formed by rotating a part of an elliptic curve or a part of a parabola. A reflector comprising: a reflector configured to reflect illumination light; and a reflector formed by rotating a part of the elliptic curve, wherein a reflection surface is separated from a first focal point of the ellipse by a distance Δ in a minor axis direction of the ellipse. A straight line (B) connecting the point (A) and the second focal point is used as a rotation axis, and is formed by rotating an elliptic curve located on the side including the first focal point among the ellipses divided by the rotation axis. A reflection surface formed by rotating a part of the parabola passes through a point (A) away from the focal point of the parabola by a distance Δ in a direction perpendicular to the symmetry axis of the parabola, and a straight line parallel to the symmetry axis ( With B) as the rotation axis, the focal point of the parabola divided by the rotation axis Including formed by rotating the parabola located on the side, the light source is the point
(A), the transparent member is rotationally symmetric with respect to the rotation axis, and is an optical system whose optical axis passes through the point (A) in a plane including the rotation axis, and the following conditional expression: (iii) and
(v), or condition (iv) and (v) the lighting device is characterized by satisfying; f <0 ... (iii) 0 <f <L ... (iv) L 2 / {2 · (L-f )} ≦ Δ ≦ 3 · L ² / {2 · (L−f)} (f) where f: focal length of the transparent member, L: distance from the rotation axis to the principal point of the transparent member. 3. The apparatus according to claim 1, further comprising an integrator for equalizing the illuminance distribution of the illumination light from the lamp, wherein the integrator comprises two lens arrays or a kaleidoscope. Lighting equipment. 4. The lighting device according to claim 1, wherein the display device modulates illumination light from the lighting device, and a projection optical system that projects the light modulated by the display device. And a projection device.