JP2001109067A - Illuminator and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminator for projector by which an illumination area is not moved with respect to a display element and stable illumination is realized even when the angle of a reflected light beam is deviated by the deflection of the reflection surface of a color wheel. SOLUTION: This illuminator is provided with a lamp 1 emitting illumination light, the reflection type color wheel 2 reflecting the illumination light so that the color of the reflected light is successively changed timewise and an integrator rod 5 uniformizing the illuminance distribution of the illumination light. Then, the wheel 2 is arranged between the lamp 1 and the rod 5 so that the illumination light emitted from the lamp 1 is made incident on the rod 5 after being reflected from the wheel 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device and a projector using the illuminating device. And a projector that projects a color image.

[0002]

2. Description of the Related Art FIGS. 10 to 12 show first to third conventional examples of a projector illuminating device provided with a reflection type color wheel. The first and second conventional examples (FIGS. 10 and 11) show a lamp (1), a reflective color wheel (2) and a relay optical system.
The illumination light emitted from the lamp (1) is reflected by the color wheel (2) and then relayed by the relay optical system.
Illuminate the display element (4) through (3) (solid lines are on-axis rays,
The dashed line represents the outermost ray. ). The color wheel (2) is composed of a plurality of (R, G, B, etc.) color filters having different reflected light colors, and a motor or the like is provided so that the color light illuminating the display element (4) is sequentially switched over time. And can be rotated (ax: rotation axis). Since the light source image (LI) is not an ideal point, it is formed near the color wheel (2) as shown in FIGS.

The third conventional example (FIG. 12) is composed of a lamp (1), an integrator rod (5), a reflective color wheel (2) and a relay optical system (3). The configuration is the same as that of the first and second conventional examples, except that an integrator rod (5) for uniformizing is added. A light source image (LI) of the lamp (1) is formed on the entrance end face of the integrator rod (5), and the exit end face of the integrator rod (5) emits surface light uniformly with the incident illumination light.
Since the exit end face of the integrator rod (5) is conjugate with the display surface of the display element (4),
The illumination light emitted from (5) is reflected by the color wheel (2), and then passes through the relay optical system (3) to illuminate the entire surface of the display element (4). External light.). The third conventional example is disclosed in U.S. Pat. No. 5,863,125 in that the illuminance distribution of the illumination light is made uniform before reflection on the color wheel (2).
It has the same basic configuration as the lighting device described in the specification and US Pat. No. 5,921,650.

[0004]

In the color wheel (2) used in the first to third conventional examples, a plurality of reflecting surfaces having different reflected light colors are all perpendicular to the rotation axis (ax). Since they are located, all the illumination light from the lamp (1) is reflected at the same angle. However, if the perpendicularity of each reflecting surface with respect to the rotation axis (ax) varies due to a manufacturing error or an assembly error, or the rotation axis (ax) is loose, the reflecting surface swings and the direction of the reflected light is changed. It changes greatly. This will be described in more detail with reference to FIG.

FIG. 14 shows the influence of the deflection of the reflection surface of the color wheel (2) when the reflection surface is developed. Further, R1 and R2 are reflection surfaces of the color wheel (2), R1 indicates a reflection surface (solid line) before swinging, and R2 indicates a reflection surface (dashed line) after swinging. As can be seen from the figure, the axial ray from the imaging point (P) is reflected on the reflection surface (R
When reflected by 1), an image is formed on the axis of the display element (4) (the optical path is indicated by a solid line), but when reflected by the reflecting surface (R2) after swinging, the axis of the display element (4) is formed. An image is formed outside (the optical path is indicated by a broken line). At this time, the reflected ray angle changes by twice the deflection angle of the reflecting surface. When the illumination light is tilted due to the deflection of the reflection surface, the illumination area moves on the display element (4).

[0006] The position of the illumination area with respect to the display element (4) is set so as to cover the effective portion of the display element (4) with a margin. However, when the illumination area moves significantly, an area where the illumination light does not reach the effective part occurs,
Vignetting occurs in the lighting area. Further, when the peripheral part of the illumination area is located on the effective part of the display element (4) due to the movement of the illumination area, the effective part is partially darkened, causing uneven illuminance. If vignetting or partial illuminance unevenness of the illumination area occurs, color unevenness will occur in the projected image,
It is necessary to take measures to reduce the influence of the deviation of the reflected light beam angle which causes the deviation.

The present invention has been made in view of such a situation, and even if the reflected light beam angle shifts due to the deflection of the reflecting surface of the color wheel, the illumination area does not move with respect to the display element. It is a first object of the present invention to provide a lighting device for a projector capable of performing the above-mentioned lighting. It is a second object of the present invention to provide a projector capable of obtaining a high-quality projected image without color unevenness.

[0008]

In order to achieve the first object, a lighting device according to a first aspect of the present invention comprises a lamp for emitting illumination light and an illumination light so that a reflected light color is sequentially switched in time. In a lighting device for a projector having a reflective color wheel for reflecting light and an integrator for uniformizing the illuminance distribution of the illumination light, the illumination light from the lamp is reflected by the color wheel and then enters the integrator. Thus, a color wheel is arranged between the lamp and the integrator.

In order to achieve the second object, a projector according to a second aspect of the present invention includes a lighting device according to the first aspect of the invention, a display element for modulating illumination light from the illumination device,
A projection optical system for projecting light modulated by the display element,
It is characterized by having.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a lighting device and a projector embodying the present invention will be described with reference to the drawings. In the above-described conventional examples (FIGS. 10 to 12 and FIG. 14) and the embodiments, the same or corresponding parts are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

<< First Embodiment (FIGS. 1 to 3) >> FIGS.
FIG. 3 shows an optical configuration of the first embodiment. FIG. 1 is a schematic diagram showing a schematic optical configuration of the illumination device. This lighting device includes a lamp (1), a reflective color wheel (2), an integrator rod (5), and a relay optical system (3). The illuminating light emitted from the lamp (1) is reflected by the color wheel (2), and the color of the reflected light is sequentially switched in time. The illumination light reflected by the color wheel (2) is incident on an integrator rod (5) for making the illuminance distribution uniform.

The integrator rod 5 is a polygonal glass body or a hollow cylindrical body formed by combining a plurality of mirrors. Illumination light incident on the integrator rod (5) at various angles is reflected many times on the side surface, resulting in a spatial energy distribution.
(That is, the illuminance distribution) is made uniform. And the display element
The light is emitted as diffused light from the emission end face conjugate with the display surface of (4). An integrator such as a fly-eye made of a lens array may be used instead of the integrator rod (5) as long as it has a function of making the illuminance distribution of the illumination light uniform. The illumination light emitted from the integrator rod (5) illuminates the display element (4) through the relay optical system (3). The display element (4) is a light modulation element that modulates illumination light to project a display image, and examples thereof include a DMD (Digital Micromirror Device) and an LCD.
(liquid crystal display) and the like.

The DMD has a display surface on which a large number of micromirrors are arranged in a matrix, and one micromirror constitutes one pixel of a display image.
The tilt of each micromirror is individually driven and controlled for light modulation, and each micromirror can take two tilt states, an ON state and an OFF state. The micromirror in the ON state reflects illumination light toward the inside of the projection optical system, and the micromirror in the OFF state reflects illumination light outside the projection optical system. Therefore,
Only the light reflected by the micromirror in the ON state reaches the projection target surface (for example, the screen surface) by the projection optical system,
As a result, a display image composed of a light and dark pattern is formed on the projection surface.

Next, a projector to which the lighting device of FIG. 1 is applied will be described. FIG. 2 is a front view of the projector viewed from the back side of the DMD (4D), and FIG. 3 is a top view of the projector viewed from above. In the figure, AX1 is the illumination system optical axis, and AX2 is the projection system optical axis. The projector according to the present embodiment includes an illumination device, a DMD (4D) that modulates illumination light from the illumination device, and a projection optical system (9) that projects light modulated by the DMD (4D). are doing. The lighting device includes a lamp (1), a color wheel (2), an integrator rod (5), first to third relay lenses (3a to 3).
c), flat mirror (7), and TIR (Total Internal Refle)
ction) prism (8). Note that DMD (4
D) corresponds to the display element (4), and the first to third relay lenses (3a to 3c) correspond to the relay optical system (3).

The illumination light emitted from the lamp (1) is first reflected by the color wheel (2). This color wheel
(2) is composed of multiple (R, G, B) color filters with different reflected light colors, and can be rotated by a motor etc. so that the color light illuminating the DMD (4D) is sequentially switched in time
(ax: rotation axis). The illumination light reflected by the color wheel (2) passes through the integrator rod (5), so that the illuminance distribution is made uniform. By making the illuminance distribution uniform, the illuminance difference between the on-axis and outermost axes on the display surface of the DMD (4D) is eliminated.

The illumination light emitted from the integrator rod (5) passes through the first and second relay lenses (3a, 3b),
The light path is bent obliquely upward by reflection at the plane mirror (7). The illumination light reflected by the plane mirror (7)
After passing through the third relay lens (3c), a TIR prism
The angle is converted in (8). The TIR prism (8) is composed of a first prism (8a) and a second prism (8b) (FIG. 3). The TIR prism (8) allows the input light and the output light to the DMD (4D) to be separated. Separation takes place. 1st prism
Since the third relay lens (3c) is joined to (8a),
The illumination light that has passed through the third relay lens (3c) is used as is in the first
The light enters the prism (8a). Illumination light incident on the first prism (8a) is reflected on the reflection surface {the first and second prisms (8a, 8b) are opposed to the reflection surface facing the second prism (8b) at a predetermined interval. They are located in parallel. } And is totally reflected by DMD (4
D) is illuminated from an oblique 45 ° direction. Then, the illumination light is optically modulated by reflection at the DMD (4D).

Since the DMD (4D) is configured such that each micromirror can take two inclined states (ON state and OFF state), the micromirror in the ON state transmits illumination light to the projection optical system (9). The illumination light is reflected toward the outside of the projection optical system (9) by the micro mirror in the OFF state. Therefore, the light reflected by the micromirror in the ON state and then transmitted through the TIR prism (8) in the order of the first and second prisms (8a, 8b) is incident on the projection optical system (9), and is thus affected. A display image is formed on a projection plane (not shown).

In the color wheel (2) used in the present embodiment, since a plurality of reflecting surfaces having different reflected light colors are all located perpendicular to the rotation axis (ax), the
The illumination light from (1) is all reflected at the same angle. If there is variation in the perpendicularity of each reflecting surface with respect to the rotation axis (ax), or if there is backlash in the rotation axis (ax), the reflected light beam angle will shift due to the deflection of the reflecting surface of the color wheel (2). However, the illumination area does not move with respect to the DMD (4D). This will be described in detail below.

According to the illumination system configuration of this projector, since the color wheel (2) is arranged between the lamp (1) and the integrator rod (5), the illumination light from the lamp (1) is After being reflected in 2), it is incident on the integrator rod (5). Since the incident end face of the integrator rod (5) is located near the reflecting surface of the color wheel (2), even if the reflecting surface of the color wheel (2) fluctuates and the reflected ray angle shifts, the illuminating light is transmitted to the integrator rod (5). It is incident on the incident end face of 5). In FIG. 13, the reflected light beam before the reflection surface of the color wheel (2) is shaken is indicated by a solid line, and the reflection light beam after the reflection surface of the color wheel (2) is shaken is indicated by a broken line.

The spatial energy distribution at the entrance end of the integrator rod (5) is not reflected in the spatial energy distribution at the exit end. Therefore, if the reflected light from the color wheel (2) is incident on the integrator rod (5), the illumination light with a uniform illuminance distribution will be emitted regardless of the deflection of the reflection surface of the color wheel (2). ) From the exit end face. Since the optical path after the exit end face of the integrator rod (5) does not change, the illumination area does not move on the display element (4).

As described above, with the use of the lighting device of the present embodiment, even if the angle of the reflected light beam shifts due to the deflection of the reflection surface of the color wheel (2), the illumination light is emitted by the color wheel (2). After being reflected, the light enters the integrator rod (5), so that the illumination area does not move with respect to the DMD (4D), which is the display element (4), and stable illumination is possible. Therefore, according to the projector of the present embodiment, it is possible to obtain a high-quality projected image free from color unevenness due to vignetting of an illumination area and partial illuminance unevenness.

<< Second Embodiment (FIGS. 4 to 6) >> FIGS.
FIG. 6 shows an optical configuration of the second embodiment. FIG. 4 is a schematic diagram showing a schematic optical configuration of the illumination device. This lighting device consists of a lamp (1), a reflective color wheel (2), a deflecting element (6), an integrator rod (5A), and a relay optical system.
It consists of (3). The illumination light emitted from the lamp (1) first enters the deflection element (6). This deflection element (6)
It consists of a right-angle prism that satisfies the condition of total reflection, and the incident illumination light is totally reflected by the deflection element (6) toward the color wheel (2). When a reflection type color wheel (2) is used, it is necessary to separate the incident light and the reflected light.In this embodiment, the separation is performed by using the deflecting element (6), so that the lamp is used. The degree of freedom in arrangement between the (1) side and the display element (4) side is improved.

The illumination light reflected by the deflecting element (6) has its reflected light color sequentially changed over time by reflection on the color wheel (2). The illumination light reflected by the color wheel (2) passes through the deflecting element (6), and then enters an integrator rod (5A) for uniformizing the illuminance distribution. This integrator rod (5A) has the same function as the integrator rod (5) used in the first embodiment. However, the incident end face of the integrator rod (5A) is located substantially parallel to the exit face of the opposing deflection element (6) at a predetermined interval. Integrator rod
The illumination light emitted from (5A) illuminates the display element (4) through the relay optical system (3).

Next, a projector to which the lighting device of FIG. 4 is applied will be described. FIG. 5 is a front view of the projector viewed from the back side of the DMD (4D), and FIG. 6 is a top view of the projector viewed from above. The projector according to the present embodiment includes an illumination device, a DMD (4D) that modulates illumination light from the illumination device, and a projection optical system (9) that projects light modulated by the DMD (4D). are doing. The lighting device is composed of a lamp (1), a color wheel (2), a deflecting element.
(6), integrator rod (5A), first to third relay lenses (3a to 3c), deflection prism (10), and TIR prism
It consists of (8). The feature of this embodiment is that the deflecting element (6) is used for separating the incoming / reflected light at the color wheel (2), and the deflecting prism (10) is provided in the relay system (3a to 3c).
Is located. Otherwise, the configuration is almost the same as that of the first embodiment, and the effect is almost the same as that of the first embodiment.

The illumination light emitted from the lamp (1) is reflected in the order of the deflecting element (6) and the color wheel (2), and then passes through the integrator rod (5A) so that the illuminance distribution is made uniform. You. The illumination light emitted from the integrator rod (5A) passes through the first and second relay lenses (3a, 3b), and then enters the square prism-shaped deflection prism (10). Illumination light incident on the deflection prism (10) is totally reflected by the reflection surface (RT), then mirror-reflected by the reflection surface (RM), and further reflected by the reflection surface (RT).
And exits the deflection prism (10). That is, the illumination light path is bent obliquely upward at an obtuse angle by the two reflection surfaces (RT, RM) inside the deflection prism (10).

The illumination light whose optical path is bent by the deflection prism (10) passes through the third relay lens (3c), and then passes through the first and the first relay lenses (3c).
The light enters the TIR prism (8) composed of the second prisms (8a, 8b). Illumination light incident on the first prism (8a) is totally reflected by the reflection surface facing the second prism (8b), and is reflected by the DMD (4).
D) is illuminated from an oblique 45 ° direction. Then, the illumination light is optically modulated by reflection at the DMD (4D). The modulated light is applied to the TIR prism in the order of the first and second prisms (8a, 8b).
After passing through (8), the light enters the projection optical system (9), thereby forming a display image on a projection surface (not shown).

According to the illumination system configuration of this projector, the deflection prism arranged in the relay system (3a-3c)
According to (10), the illumination optical path before incidence on the TIR prism (8) is bent at an obtuse angle, so that the restriction on the arrangement by the relay lenses (3a, 3b) and the like is relaxed. Therefore, the lamp (1)
Are shorter than in the first embodiment (FIG. 2) in a state where the projectors are arranged horizontally, and the projector is easily made thin and compact. The deflection prism (10) has one total reflection surface (RT) and one mirror reflection surface (RM), and the reflection surface (RT) that performs total reflection is also used as an exit surface that is a transmission surface. Has become. Deflection prism that internally performs total reflection and mirror reflection in this way
When (10) is used, the illumination light paths are superposed in the deflection prism (10), so that the light path length is compressed. As a result, the size of the optical system can be reduced, and it is not necessary to use a large reflecting surface.

<< Third Embodiment (FIGS. 7 to 9) >> FIGS.
FIG. 9 shows an optical configuration of the third embodiment. FIG. 7 is a top view of the projector viewed from above, and FIG.
FIG. 9 is a front view of the projector viewed from the back side of D (4D), and FIG. 9 is a side view of a main part of the projector viewed from the side. The projector according to the present embodiment includes a lighting device, a DMD (4D) that modulates illumination light from the lighting device,
A projection optical system (9) for projecting light modulated by D (4D). The lighting device includes a lamp (1), a reflective color wheel (2), a deflecting element (6), an integrator rod (5A), first to third relay lenses (3a to 3c),
It comprises a second plane mirror (7a, 7b) and a TIR prism (8).

The feature of this embodiment is that, instead of the deflection prism (10) in the second embodiment, first and second plane mirrors (7a, 7b) are provided in a relay system (3a-3c). It is located at the point. Otherwise, the configuration is almost the same as that of the second embodiment, and the effect is almost the same as that of the second embodiment. In addition, the bending of the illumination optical path using the first and second plane mirrors (7a, 7b) has an effect that the height of the projector is relatively low and the bottom area is also compact.

The illumination light emitted from the lamp (1) is reflected in the order of the deflecting element (6) and the color wheel (2), and then passes through the integrator rod (5A) to make the illuminance distribution uniform. You. After the illumination light emitted from the integrator rod (5A) passes through the first relay lens (3a), its optical path is bent obliquely downward by reflection on the first plane mirror (7a). The illumination light reflected by the first plane mirror (7a)
After passing through the second relay lens (3b), the second flat mirror (7
The light path is bent obliquely upward by the reflection in b).

The illumination light reflected by the second plane mirror (7b) passes through a third relay lens (3c) and then enters a TIR prism (8) composed of first and second prisms (8a, 8b). I do.
Illumination light incident on the first prism (8a) is incident on the second prism (8a).
The light is totally reflected by the reflection surface facing b) and illuminates the DMD (4D) from an oblique 45 ° direction. And the illumination light is DMD
The light is modulated by reflection at (4D). The modulated light passes through the TIR prism (8) in the order of the first and second prisms (8a, 8b), and then enters the projection optical system (9), so that the light is projected on the projection surface (not shown). Thus, a display image is formed.

[0032]

As described above, if the illumination device according to the present invention is used, even if the angle of the reflected light beam is shifted due to the deflection of the reflection surface of the color wheel, the illumination light is reflected by the color wheel and then transmitted to the integrator. Since the light enters, the illumination area does not move with respect to the display element, and stable illumination is possible. Therefore, according to the projector of the invention, it is possible to obtain a high-quality projected image without color unevenness.

[Brief description of the drawings]

FIG. 1 is an optical configuration diagram showing a lighting device according to a first embodiment.

FIG. 2 is a front view showing a schematic optical configuration of the projector according to the first embodiment.

FIG. 3 is a top view illustrating a schematic optical configuration of the projector according to the first embodiment.

FIG. 4 is an optical configuration diagram showing a lighting device according to a second embodiment.

FIG. 5 is a front view showing a schematic optical configuration of a projector according to a second embodiment.

FIG. 6 is a top view illustrating a schematic optical configuration of a projector according to a second embodiment.

FIG. 7 is a top view illustrating a schematic optical configuration of a projector according to a third embodiment.

FIG. 8 is a front view showing a schematic optical configuration of a projector according to a third embodiment.

FIG. 9 is an essential part side view showing a schematic optical configuration of a projector according to a third embodiment.

FIG. 10 is an optical configuration diagram showing a lighting device of a first conventional example.

FIG. 11 is an optical configuration diagram showing a lighting device of a second conventional example.

FIG. 12 is an optical configuration diagram showing a third conventional illumination device.

FIG. 13 is an optical path diagram for explaining an optical function in the embodiment of the present invention.

FIG. 14 is an optical path diagram for explaining an optical action in a conventional example.

[Explanation of symbols]

 1 ... lamp 2 ... color wheel 3 ... relay optical system 3a ... first relay lens 3b ... second relay lens 3c ... third relay lens 4 ... display element 4D ... DMD (display element) 5 ... integrator rod (integrator) 5A ... Integrator rod (integrator) 6 Deflecting element 7 Planar mirror 7a First plane mirror 7b Second plane mirror 8 TIR prism 8a First prism 8b Second prism 9 Projection optical system 10 Deflection prism RT … Reflective surface RM… Reflective surface AX1… Illumination optical axis AX2… Projection optical axis

Claims (2)

[Claims] 1. A projector comprising: a lamp that emits illumination light; a reflection-type color wheel that reflects illumination light so that a reflected light color is sequentially switched in time; and an integrator that equalizes the illuminance distribution of the illumination light. A lighting device, comprising: a color wheel disposed between a lamp and an integrator such that illumination light from the lamp is reflected by the color wheel and then enters the integrator. 2. The illumination device according to claim 1, further comprising: a display element for modulating illumination light from the illumination device; and a projection optical system for projecting the light modulated by the display element. Projector.