JP5266619B2 - projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of increasing the availability of light rays and improving the brightness of a projected image in a tilt projection, by imparting the reflecting face of a reflector the with special characteristics. <P>SOLUTION: An imaginary lower half VDS is rotated about a vertex OP by a predetermined angle, in a positive direction with respect to tilting and shifting directions, that is, counterclockwise on paper, and a lower-half face DS is disposed at this position, such that the lower-half face DS and an upper-half face US are disposed asymmetrically. Tilt projection in such a condition is increased in the illumination intensity of light on screen and improves the light utilization efficiency. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

The present invention relates to a projector that illuminates a liquid crystal panel or the like with illumination light from a light source device and projects an image of the liquid crystal panel or the like with a projection optical system.

In order to ensure the uniformity of the illuminance on the illuminated surface in a liquid crystal projector, etc., it is known that the reflector of the light source is divided into a plurality of surfaces and the condensing characteristics of the divided reflective surfaces are individually changed. (For example, refer to Patent Document 1).

On the other hand, in the projection by the projector, what performs so-called tilt projection is known,
As a method of tilt projection, it is common to shift the position of the optical axis of the projection lens from the position of the optical axis to the liquid crystal panel or the like that is the preceding stage (see, for example, Patent Document 2).
Japanese Patent No. 3499089 JP 2004-85726 A

However, when the projection lens is shifted and the projection is performed, a positional deviation occurs between the projection lens and the light source side. Thereby, the symmetry with respect to the tilt direction is broken between the projection lens and the front stage of the projection lens. From such a position shift, a part of the light is lost when entering the projection lens, and the utilization rate of the light to be projected may be reduced. Such a decrease in light utilization efficiency is not solved even if a reflector such as the above-mentioned patent document is used.

Therefore, the present invention provides a projector that improves the light use efficiency during tilt projection and improves the brightness of the projected image by giving a special characteristic to the reflecting surface of the reflector on the light source side. For the purpose.

In order to solve the above problems, a projector according to the present invention includes: (a) a light source device having a light source that emits light source light; and a reflector that emits illumination light by reflecting the light source light on a concave reflecting surface; (B) A light modulation device illuminated by illumination light from the light source device, and (c) a projection optical system that projects image light formed by the light modulation device. In this projector, (d) the projection optical system is arranged with the central axis shifted in the tilt direction with respect to the system optical axis passing through the light modulation device, and (e) the reflector's light source is arranged on the central axis. The reflecting surface is formed of a pair of curved surfaces obtained by dividing one of the elliptical and parabolic quadratic curved surfaces in the direction across the central axis passing through the system optical axis, thereby forming the first and second half surfaces. and, a second half-plane which is arranged on the positive side with respect to the tilt direction, when the number of inversions in the tilt direction from the exit point from the light source device of the illuminating light to the entrance point of the optical modulator is an odd number By applying at least one of rotation in a positive direction and a shift in the negative direction of the optical axis from the position satisfying the symmetry relationship around the vertex of the reflection surface, the first half surface and the second To make it asymmetrical And butterflies.

In the projector, the first half surface and the second half surface constituting the reflection surface of the reflector are:
Since the system optical axis is sandwiched and the directions are divided into two and are asymmetrical to each other, the light modulator can be illuminated asymmetrically with respect to the tilt direction. In tilt projection, the image light formed by the light modulator is projected into the projection optical system. Can be efficiently incident. Thereby, the utilization efficiency of light can be improved and the brightness of the projected image by the projection optical system can be improved.

As a specific aspect of the present invention, the reflector includes a pair of curved surfaces obtained by dividing one of the elliptical and parabolic quadratic curved surfaces with the central axis therebetween, and the first and second half surfaces. And at least one of the first half and the second half is provided with at least one of rotation around the vertex of the reflecting surface and a shift in the system optical axis direction from a position satisfying the symmetry relationship, The first half surface and the second half surface are asymmetric. In this case, the reflector forms the first and second half surfaces by a pair of curved surfaces obtained by dividing the elliptical or parabolic quadratic curved surface with the central axis therebetween. Light beam-shaped illumination light suitable for illumination can be formed. Further, at least one of the first and second half faces is rotated or shifted from a position satisfying the symmetry relationship, so that the first half face and the second half face can be asymmetric with respect to each other.

As a specific aspect of the present invention, when the number of inversions of illumination light is an odd number, the second half surface is disposed on the positive side with respect to the tilt direction and rotated in the positive direction of the tilt direction. In this case, illumination light emitted from the half surface on the positive side with respect to the tilt direction among the reflecting surfaces of the reflector is shifted to a more converged state by the rotation, and irradiation with an angle corresponding to the tilt direction is performed.

Further, as a specific aspect of the present invention, when the number of inversions of the illumination light is an odd number, the second half surface is arranged on the positive side with respect to the tilt direction and shifted in the negative direction of the optical axis. The In this case, illumination light emitted from a half surface on the positive side with respect to the tilt direction among the reflecting surfaces of the reflector is shifted to a more converged state by the shift, and irradiation with an angle corresponding to the tilt direction is performed.

As a specific aspect of the present invention, a projector according to the present invention includes a color separation optical system that separates illumination light into color light for each predetermined wavelength and forms each color light, and each color light from the color separation optical system. It further includes a light modulation device for each color that is illuminated to form image light of each color, and a combining optical system that combines the image light of each color. In this case, each color light modulation device can be illuminated with the corresponding color light, and color images can be projected by synthesizing the image light of each color by the combining optical system to form the combined light.

[First Embodiment]
FIG. 1 is a conceptual diagram for explaining the projector according to the first embodiment. The projector 100 in this embodiment includes a light source device 10, an illumination optical system 20, and a color separation optical system 30.
And liquid crystal light valves 40a, 40b, and 40c that are light modulators, a cross dichroic prism 50 that is a combining optical system, and a projection lens 60 that is a projection optical system.

First, in the light source device 10, the light source 11 is, for example, a high-pressure mercury lamp or the like, and generates substantially white light source light having a light amount sufficient to form image light. The reflector 12 has a concave reflecting surface RS that bends the light source light in a predetermined optical path direction by reflection. The reflecting surface RS is a pair of curved surfaces obtained by dividing the elliptical surface with the central axis between the first half surface and the second half surface, and these are arranged asymmetrically with each other. The first and second half surfaces are divided into two parts with the system optical axis OA interposed therebetween.

In the present embodiment, the first half surface is the lower half (−y of the reflection surface RS with respect to the system optical axis OA).
The lower half surface DS occupying the region of the side portion) is the lower half surface DS, and the second half surface is the upper half surface US occupying the region of the upper half (+ y side portion) of the reflective surface RS. Further, particularly in the present embodiment, the asymmetric shape of the reflection surface RS of the reflector 12 as described above is formed by moving the lower half surface DS from the reference position (details will be described later).

The illumination optical system 20 includes a collimating lens 2 that is a light collimating unit that collimates the light beam direction of the light source light.
2, first and second fly-eye lenses 23a and 23b, which are a pair of fly-eye lenses constituting an integrator optical system for dividing and superimposing light, and a polarization conversion element 24 that aligns the polarization direction of light, Superimposing lens 25 that superimposes the light passing through both fly-eye lenses 23a and 23b.
And a mirror 26 that bends the optical path of the light, thereby forming uniform illumination light.

In the illumination optical system 20, the collimating lens 22 converts the light beam direction of the light source light into substantially parallel.

The first and second fly-eye lenses 23a and 23b are each composed of a plurality of element lenses arranged in a matrix, and the light that has passed through the collimating lens 22 is divided by these element lenses to individually collect and diverge light. . The polarization conversion element 24 is formed of a PBS array,
It has the role of aligning the polarization direction of each partial light beam divided by the first fly-eye lens 23a with linear polarization in one direction. The superimposing lens 25 appropriately converges the illumination light that has passed through the polarization conversion element 24 as a whole, and liquid crystal light valves 40a, 40b, and 40 that are light modulation devices for the respective colors in the subsequent stages.
Enables superimposed illumination for c.

As can be seen from the above description, the illumination light that has passed through the pair of first and second fly-eye lenses 23a and 23b, the polarization conversion element 24, and the superimposing lens 25 is a color separation optical system 30 described in detail below. Then, the liquid crystal light valves 40a, 40b, and 40c are uniformly illuminated with polarized light in a specific direction. The illumination light emitted from the illumination optical system 20 is incident on the color separation optical system 30 after the direction of the optical path is bent by the mirror 26.

The color separation optical system 30 includes first and second dichroic mirrors 31a and 31b, reflection mirrors 32a, 32b, and 32c, and three field lenses 33a, 33b, and 33c, and is formed by the illumination optical system 20. The light is separated into three colors of red (R), green (G), and blue (B), and each color light is guided to the liquid crystal light valves 40a, 40b, and 40c at the subsequent stage. More specifically, first, the first dichroic mirror 31a transmits R light and reflects G light and B light among the three colors of RGB. The second dichroic mirror 31b reflects G light and transmits B light out of the two colors of GB. Next, in this color separation optical system 30, the first
The R light transmitted through the dichroic mirror 31a is incident on the field lens 33a for adjusting the incident angle via the reflecting mirror 32a. The first dichroic mirror 31a
Then, the G light reflected by the second dichroic mirror 31b is incident on the field lens 33b for adjusting the incident angle. Further, the B light that has passed through the second dichroic mirror 31b is relay lenses LL1, LL2 and reflection mirrors 32b, 33c.
Then, the light enters the field lens 33c for adjusting the incident angle.

The liquid crystal light valves 40 a, 40 b, and 40 c are non-light-emitting light modulation devices that modulate the spatial intensity distribution of incident illumination light, and are illuminated corresponding to each color light emitted from the color separation optical system 30. Three liquid crystal panels 41a, 41b, 41c and the respective liquid crystal panels 41a-4
Three first polarizing filters 42a to 42c arranged on the incident side of 1c and three second polarizing filters 43a to 43 arranged on the emission side of the liquid crystal panels 41a to 41c, respectively.
c. The R light transmitted through the first dichroic mirror 31a is reflected by the field lens 3
The light enters the liquid crystal light valve 40a through 3a or the like and illuminates the liquid crystal panel 41a of the liquid crystal light valve 40a. The G light reflected by both the first and second dichroic mirrors 31a and 31b is incident on the liquid crystal light valve 40b via the field lens 33b and the like, and illuminates the liquid crystal panel 41b of the liquid crystal light valve 40b. The B light reflected by the first dichroic mirror 31a and transmitted through the second dichroic mirror 31b is incident on the liquid crystal light valve 40c via the field lens 33c and the like, and the liquid crystal panel 41c of the liquid crystal light valve 40c.
Illuminate. Each of the liquid crystal panels 41a to 41c modulates the spatial intensity distribution of the incident illumination light, and the three colors of light incident on each of the liquid crystal panels 41a to 41c correspond to the respective liquid crystal panels 41a to 41c.
Modulation is performed in accordance with a drive signal or an image signal input to 1c as an electrical signal. At this time, the polarization direction of the illumination light incident on the liquid crystal panels 41a to 41c is adjusted by the first polarizing filters 42a to 42c, and the light is emitted from the liquid crystal panels 41a to 41c by the second polarizing filters 43a to 43c. Modulated light having a predetermined polarization direction is extracted from the modulated light. As described above, each of the liquid crystal light valves 40a, 40b, and 40c forms image light of each color corresponding thereto.

The cross dichroic prism 50 combines the image lights of the respective colors from the liquid crystal light valves 40a, 40b, and 40c. More specifically, the cross dichroic prism 50
Has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a pair of dielectric multilayer films 51a and 51b intersecting in an X shape are formed at the interface where the right-angle prisms are bonded together. One first dielectric multilayer film 51a reflects R light and the other second dielectric multilayer film 51b.
Reflects B light. The cross dichroic prism 50 reflects the R light from the liquid crystal light valve 40a by the dielectric multilayer film 51a and emits it to the right in the traveling direction, so that the liquid crystal light valve 4
The G light from 0b goes straight and is emitted through the dielectric multilayer films 51a and 51b, and the B light from the liquid crystal light valve 40c is reflected by the dielectric multilayer film 51b and emitted to the left in the traveling direction. In this way, the R light, the G light, and the B light are combined by the cross dichroic prism 50 to form combined light that is image light based on a color image.

The projection lens 60 enlarges the image light by the combined light formed through the cross dichroic prism 50 at a desired magnification and projects a color image on a screen (not shown). Here, the projection lens 60 is arranged in a state where the central axis is shifted in the tilt direction with respect to the optical axis of the illumination light, and performs projection by so-called tilt projection (details will be described later).

FIG. 2 is a development view showing an optical path of the projector 100 of FIG. In FIG. 2,
Although the optical path of R light is shown as an example, the same applies to optical paths of other colors.

Hereinafter, first, so-called tilt projection will be described with reference to FIG. In the projection lens 60, the central axis OB is the optical axis of the projection lens 60, and is shifted upward in the drawing with respect to the system optical axis OA corresponding to the central axis of the liquid crystal light valve 40a and the cross dichroic prism 50. Thereby, it is possible to perform projection with less aberration in which the entire screen is shifted upward, that is, in the + y direction, compared to the main body of the projector 100. In this embodiment, the + y direction above the paper surface is the tilt direction. The projection lens 60 includes a plurality of groups of lenses whose optical axes coincide with each other, and the entire movement in a direction perpendicular to the optical axes changes the optical axis direction in accordance with the tilt direction. Adjustment for desired zooming and focusing is appropriately performed by moving the lens or all the lenses in the optical axis direction.

Next, the illumination light in this embodiment will be considered using FIG. In particular, a component emitted from the lower half of the illumination light emitted from the light source device 10 will be considered here. That means
Among the curved surfaces constituting the reflecting surface RS of the reflector 12, the illumination light E emitted from the lower half surface DS
Consider L. Here, the lower half surface DS is arranged on the negative side with respect to the tilting direction in the projection lens 60, and as will be described later, the luminous flux of the illumination light EL is 1 corresponding to the imaging point on the optical path. Inverted times. Hereinafter, the optical path of the illumination light EL is followed in the order.

The light source light emitted radially from the light source 11 is bent in the optical path direction substantially along the system optical axis OA by reflection at the reflection surface RS of the reflector 12. At this time, of the entire illumination light,
Illumination light occupying a lower half area from the system optical axis OA is emitted as illumination light EL from the lower half surface DS. The emitted illumination light EL enters the liquid crystal light valve 40a through the illumination optical system 20 and the color separation optical system 30 as shown in FIG. As can be seen from FIG. 2, the illumination light EL is
In the illumination optical system 20 having an imaging point, the tilting direction is reversed once between the emission point from the light source device 10 and the incident point to the liquid crystal light valve 40a. That is, the vertical relationship between the light beams constituting the illumination light EL is reversed at the image formation point. Therefore, each time the inversion is performed at the imaging point, each light flux in the illumination light EL changes whether it is closer to the positive side (upper side of the drawing) or the negative side with respect to the tilt direction. In the case of FIG. 2, since the number of inversions is 1,
The illumination light EL is incident on the liquid crystal light valve 40a in a state reversed with respect to the vertical direction (that is, the tilt direction) from the state in which the reflector 12 is emitted.

Fig.3 (a) is a sectional side view for demonstrating the shape of the reflective surface RS of the reflector 12 in this embodiment. As described above, the reflection surface RS of the reflector 12 is formed in an asymmetric shape by moving the lower half surface DS from the reference position.

Hereinafter, the design process of the reflective surface RS in the present embodiment will be described with reference to FIG. First, a virtual reflecting surface is formed vertically symmetrically with the system optical axis OA as a reference symmetry axis. That is, a symmetric virtual lower half surface VDS is arranged on the upper half surface US, and this is defined as a virtual reflection surface VS. Here, the lower half surface DS is formed by rotating the virtual lower half surface VDS by a predetermined angle with respect to the vertex OP. More specifically, for example, for the virtual lower half surface VDS, the vertex OP
Is rotated in a positive direction with respect to the tilt direction by a predetermined angle, that is, counterclockwise on the paper surface (arrow in the figure), and the lower half surface DS is disposed at the position. As a result, the lower half surface DS and the upper half surface US are arranged asymmetrically with respect to each other. When the reflecting surface RS is used as the reflector 12, the illuminance of light on the screen (not shown) is increased in the projector 100 that performs tilt projection, compared with the case where the vertically reflecting virtual reflecting surface VS is used. Increases efficiency.

FIGS. 3B and 3C compare the case where the lower half surface DS is not moved from the symmetrical position. That is, FIG. 3B shows a virtual reflection surface VS that is symmetrical with respect to the vertical direction.
In other words, the irradiation of the liquid crystal light valve 40a with the illumination light EL in the comparative example using the virtual lower half surface VDS for the lower half surface is shown. On the other hand, FIG. 3C shows irradiation of the liquid crystal light valve 40a by the illumination light EL when the reflecting surface RS according to the present embodiment is used, that is, when the lower half surface DS is used as the lower half surface. As you can see by comparing the two figures, the lower half DS
In the case of using, the illumination light EL is more shifted in the direction of divergence, and as a result, irradiation at an angle corresponding to the tilt direction is performed, and it is considered that the light utilization efficiency is increased. still,
Here, the movement distance, that is, the rotation angle for the lower half surface DS may be selected in accordance with the degree of tilt, optical design, and the like.

In the above description, the lower half surface DS is formed by rotation about the vertex OP.
The formation method of S is not restricted to this. For example, in the irradiation of the illumination light EL to the liquid crystal light valve 40a, the reflection surface is also provided in the vicinity of the vertex OP, that is, at the boundary between the upper half surface US and the lower half surface DS so as to keep the irradiation smooth near the center of the irradiated region. The shape of the RS may be modified so as to maintain smoothness. That is, the curvature of the lower half surface DS in the vicinity of the vertex OP and the curvature of the upper half surface US may be appropriately modified.

Fig.4 (a) is a sectional side view for demonstrating the shape of reflective surface RS about the modification of this embodiment. In FIG. 3A, the lower half surface DS is formed by rotating the virtual lower half surface VDS with respect to the vertex OP. However, in this modification, the virtual lower half surface VDS is directed rightward on the paper surface, that is, in the direction of the system optical axis OA. Is shifted in parallel by a predetermined distance (arrow in the figure), and the lower half surface DS is arranged at this position. As a result, the lower half surface DS and the upper half surface US are arranged asymmetrically with respect to each other. Similarly, when the reflector 12 of FIG. 4A is used, in the projector 100, the illuminance of light on the screen (not shown) is increased, and the light use efficiency is improved.

4 (b) and 4 (c) are similar to FIGS. 3 (b) and 3 (c), respectively, the virtual lower half surface VD on the lower half surface.
The irradiation to the liquid crystal light valve 40a by the illumination light EL in the case of the comparative example using S and the case of the embodiment using the lower half surface DS is shown. Also in this case, the illumination light EL is more shifted in the diverging direction in the embodiment using the lower half surface DS.

[Second Embodiment]
FIG. 5A is a side sectional view for explaining the shape of the reflecting surface of the reflector used in the projector according to the second embodiment. In the present embodiment, since the structure of the projector is the same as that of the first embodiment except for the shape of the reflecting surface of the reflector, the description of the projector body is omitted.

In the reflector 12 according to the first embodiment, an asymmetric shape is formed by moving the lower half surface DS from the reference position among the lower half surface DS and the upper half surface US configured by dividing the reflection surface RS into two. In the embodiment, on the contrary, the upper half surface US is moved from the reference position. Hereinafter, the design process of the reflecting surface RS of the reflector 212 in this embodiment will be described with reference to FIG.

First, similarly to the first embodiment, a virtual reflecting surface is formed vertically symmetrically with the system optical axis OA as a reference symmetry axis. That is, a symmetric virtual upper half surface VUS is arranged on the lower half surface DS, and this is set as a virtual reflection surface VS. Here, the upper half surface US is formed by rotating the virtual upper half surface VUS by a predetermined angle with respect to the vertex OP. More specifically, for example, the virtual upper half surface VU
With respect to S, the lower half surface DS is arranged at this position by rotating it in the positive direction with respect to the tilting direction by a predetermined angle around the vertex OP, that is, counterclockwise on the paper (arrow in the figure). As a result, the lower half surface DS and the upper half surface US are arranged asymmetrically with respect to each other. Reflector 212
As described above, when the reflective surface RS is used, the first is higher than when the vertically reflective virtual reflective surface VS is used.
As in the case of the embodiment, the light utilization efficiency is improved.

FIGS. 5B and 5C compare the case where the upper half surface US is not moved from the symmetrical position. That is, FIG. 5B shows a virtual reflection surface VS that is symmetrical with respect to the vertical direction.
In other words, irradiation of the liquid crystal light valve 40a by the illumination light EL in the comparative example using the virtual upper half surface VUS as the upper half surface is shown. On the other hand, FIG.5 (c) has shown irradiation to the liquid crystal light valve 40a by illumination light EL when the reflective surface RS which is this embodiment is used, ie, when the upper half surface US is used for an upper half surface. As you can see by comparing the two figures, the upper half US
In the case of using, the illumination light EL is shifted more in the convergence direction, and thus it is considered that the light is irradiated at an angle corresponding to the tilt direction, and the light use efficiency is improved.

Fig.6 (a) is a sectional side view for demonstrating the shape of reflective surface RS about the modification of this embodiment. In FIG. 5A, the upper half surface US is formed by rotating the virtual upper half surface VUS with the vertex OP as a reference. However, in this modification, the virtual upper half surface VUS is directed leftward in the drawing, that is, the direction of the system optical axis OA is negative. Is shifted in parallel by a predetermined distance (arrow in the figure), and the upper half surface US is disposed at the position. As a result, the lower half surface DS and the upper half surface US are arranged asymmetrically with respect to each other. Even when the reflector 212 of FIG. 6A is used, the light utilization efficiency is improved similarly.

6 (b) and 6 (c) are similar to FIGS. 5 (b) and 5 (c), respectively, the upper half surface is a virtual upper half surface VU.
The irradiation to the liquid crystal light valve 40a by the illumination light EL in the case of the comparative example using S and the case of the embodiment using the lower half US is shown. Also in this case, the illumination light EL is more shifted in the convergence direction in the embodiment using the upper half surface US.

Although the projector according to the present invention has been described above, the present invention is not limited to the above embodiments.

For example, the first embodiment deforms the lower half surface DS of the reflecting surface RS, while the second embodiment deforms the upper half surface US of the reflecting surface RS, but the lower half surface DS and the upper half surface. US
Both may be deformed or moved. That is, for example, for the lower half surface DS, FIG.
As shown in FIG. 6A, the virtual lower half surface VDS is formed by rotating the virtual lower half surface VDS with the vertex OP as a reference. It may be formed by shifting the direction of the axis OA in the negative direction in parallel by a predetermined distance. Further, as shown in FIGS. 3A and 5A, the lower half surface DS and the upper half surface US are connected to the vertex O.
Each may be rotated with P as a reference.

Further, for example, when the lower half surface DS is rotated from the reference position in the first embodiment, the lower half surface DS is rotated in a positive direction with respect to the tilt direction by a predetermined angle, that is, counterclockwise on the paper surface. However, the direction of rotation does not correspond only to the tilt direction, but can be changed as appropriate according to other requirements. For example, in FIG. 2, the illumination light EL is inverted once between the emission position from the light source device 10 and the incident position on the liquid crystal light valve 40 a. Therefore, in this case, as described above, the state of the luminous flux of the illumination light EL is reversed with respect to the tilt direction in the liquid crystal light valve 40a. Similarly, when the number of times of reversal is an odd number, the rotation direction forms the same light beam state of the illumination light EL as in the above case, while when the number of times of reversal of the illumination light is an even number, the odd number of times. It ’s in the opposite direction. Therefore, it is necessary to change the direction in which the half surfaces DS and US should be rotated depending on the number of times the illumination light is inverted in the optical system used in the projector 100. Note that the determination of the moving direction according to the number of inversions of the illumination light is not limited to the case of deformation due to rotation, and the half surfaces US and DS are made parallel to each other as shown in FIGS. The same applies to the direction of shifting to.

In addition, as a premise for forming the reflection surface RS, in the above-described embodiments, the curved surface has an elliptical shape. However, for example, a parabolic quadratic curved surface may be used. .

Further, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

In the projector 100 of the above embodiment, a high-pressure mercury lamp is used as an example of the light source 11, but other lamps such as a metal halide lamp may be used instead of the high-pressure mercury lamp.

In the above embodiment, an example in which the present invention is applied to a transmissive projector has been described. However, the present invention can also be applied to a reflective projector. here,"
“Transmission type” means that the light valve including the liquid crystal panel is a type that transmits light, and “reflection type” means that the light valve is a type that reflects light. Yes. In the case of a reflection type projector, the light valve can be constituted only by a liquid crystal panel, and a pair of polarizing plates is unnecessary. The light modulation device is not limited to a liquid crystal panel or the like,
For example, a light modulation device using a micromirror may be used.

Further, as the projector, there are a front projector that projects an image from the direction of observing the projection surface and a rear projector that projects an image from the side opposite to the direction of observing the projection surface. The configuration can be applied to both.

It is a conceptual diagram for demonstrating the projector which concerns on 1st Embodiment. It is an expanded view which shows an example of the optical path concerning 1st Embodiment. (A) is a sectional side view for demonstrating the reflective surface shape of a reflector. (B), (c) is a side view for comparing irradiation of illumination light to a light modulation device. (A) is a sectional side view for demonstrating the reflective surface shape of the reflector in a modification. (B), (c) is a side view for comparing irradiation of illumination light to a light modulation device. (A) is a sectional side view for demonstrating the reflective surface shape of the reflector which concerns on 2nd Embodiment. (B), (c) is a side view for comparing irradiation of illumination light to a light modulation device. (A) is a sectional side view for demonstrating the reflective surface shape of the reflector in the modification which concerns on 2nd Embodiment. (B), (c) is a side view for comparing irradiation of illumination light to a light modulation device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Projector, 10 ... Light source device, 11 ... Light source, 12, 212 ... Reflector, 20 ... Illumination optical system, 30 ... Color separation optical system, 40a, 40b, 40c ... Liquid crystal light valve, 50 ... Cross dichroic prism, 60 ... Projection lens, RS ... reflective surface, DS ... lower half, US ... upper half

Claims (2)

A light source device comprising: a light source that emits light source light; and a reflector that emits illumination light by reflecting the light source light on a concave reflecting surface;
A light modulation device illuminated by illumination light from the light source device;
A projection optical system that projects the image light formed by the light modulation device;
A projector comprising:
The projection optical system is arranged by shifting the central axis in the tilt direction with respect to the system optical axis passing through the light modulation device,
For the light source arranged on the central axis, the reflecting surface of the reflector bisects either the elliptical or parabolic quadratic curved surface in the tilt direction across the central axis passing through the system optical axis forming a first and second half of a pair of curved surfaces obtained by the second half-plane which is arranged on the positive side with respect to the tilt direction, the exit point from the light source device of the illuminating light And when the number of inversions in the tilt direction from the incident position to the light modulation device is an odd number, rotation from the position satisfying the symmetry relationship to the positive direction of the tilt direction around the vertex of the reflecting surface and the optical axis of by providing at least one of direction negative direction of the shift, the first half and the second half and the characterized in that the asymmetrical to Help projector. A color separation optical system for separating the illumination light into colored light for each predetermined wavelength and forming each colored light;
The light modulation device for each color that is illuminated by each color light from the color separation optical system to form image light of each color;
A synthesis optical system for synthesizing the image lights of the respective colors;
The projector according to claim 1, further comprising:

Images