WO2016147580A1

WO2016147580A1 - Projector

Info

Publication number: WO2016147580A1
Application number: PCT/JP2016/001089
Authority: WO
Inventors: 洋一宍戸; 成松　修司
Original assignee: セイコーエプソン株式会社
Priority date: 2015-03-13
Filing date: 2016-03-01
Publication date: 2016-09-22
Also published as: JP2016170302A

Abstract

The purpose of the present invention is to provide a projector capable of achieving a reduction in size. This projector 1 is provided with: an illumination device for emitting a first polarized light; a plurality of light modulation devices which modulate each of a plurality of coloured lights included in the emitted light; a colour separation/synthesis device which is disposed between the illumination device and the plurality of light modulation devices, separates the plurality of coloured lights from the emitted light incident on the inside via an entry/emission surface, causes the plurality of coloured lights to become incident on each of the plurality of light modulation devices, and emits, via the entry/emission surface, synthesized light obtained by synthesizing the plurality of coloured lights incident thereon which have been modulated by the plurality of light modulation devices; a polarized-light separation device which is disposed between the illumination device and the colour separation/synthesis device, transmits one from among the first polarized light and a second polarized light orthogonal to the first polarized light, and reflects the other; and a projection optical device for projecting the synthesized light emitted from the polarized-light separation device. The projection optical device is provided with a plurality of lenses. At least one lens among the plurality of lenses is disposed between the illumination device and the colour separation/synthesis device.

Description

projector

The present invention relates to a projector.

Conventionally, a light source, a color separation device that separates a plurality of color lights from the light emitted from the light source, a plurality of light modulation devices that respectively modulate the plurality of separated color lights, and a color that combines the plurality of modulated color lights There is known a projector including a combining device and a projection optical device that projects the combined light. As such a projector, there is known a projector (projection device) in which the color separation device and the color synthesis device are configured by one prism assembly (for example, see Patent Document 1).
In the projector described in Patent Document 1, light emitted from a light source passes through a combination lens, infrared rays are removed by a cold mirror, pass through the combination lens, and enter a PBS (Polarization Beam Splitter). Since the coating on the inner surface of the PBS transmits p-polarized light and reflects s-polarized light, p-polarized reflected light is incident on the prism assembly. Then, the light separated into the three colors by the prism assembly is incident on three reflective liquid crystal light valves as light modulators. The light modulated by these reflective liquid crystal light valves is incident on the prism assembly again and synthesized, and is projected by the projection lens via the PBS.

Special table 2003-522966 gazette

By the way, the projection lens is generally composed of a plurality of lenses, and the reflection type liquid crystal light valve is arranged at the back focus position of the most light-incident side lens among the plurality of lenses.
On the other hand, in the projection apparatus described in Patent Document 1, a PBS is disposed in addition to the prism assembly between the projection lens and the reflective liquid crystal light valve. For this reason, the distance (back focus) between the lens closest to the light incident side and the reflective liquid crystal light valve is increased. Thus, when the said distance becomes long, the dimension in alignment with the central axis of a projection lens will become large, and there exists a problem that a projection lens and by extension a projector will become large.

The present invention aims to solve at least a part of the above problems, and an object of the present invention is to provide a projector that can be miniaturized.

A projector according to one embodiment of the present invention is provided in accordance with each of a lighting device that emits first polarized light and a plurality of colored lights included in the emitted light emitted by the lighting device, and the plurality of colored lights are provided. A plurality of light modulation devices that respectively modulate the light modulation device, the illumination device, and the plurality of light modulation devices are arranged to separate the plurality of color lights from the emitted light incident inside through an incident / exit surface. A color separation / synthesis device that emits combined light, which is incident on each of the plurality of light modulation devices, and combines the plurality of color lights that are modulated and incident by the plurality of light modulation devices, through the input / output surface; A polarization separation device that is disposed between an illumination device and the color separation / synthesis device, transmits one of the first polarization and the second polarization orthogonal to the first polarization, and reflects the other; Get out of polarization separator A projection optical device that projects the combined light, and the projection optical device includes a plurality of lenses, and at least one of the plurality of lenses includes the illumination device and the color separation / synthesis device. It is arrange | positioned between.

An example of the color separation / synthesis device is a dichroic prism.
Examples of the polarization separation device include a plate type PBS and a prism type PBS.
Furthermore, examples of the projection optical device include a lens that passes through the combined light synthesized by the color separation / synthesis device, in addition to a plurality of lenses constituting the projection optical device.
According to the above aspect, at least one lens among the plurality of lenses constituting the projection optical device in the lens design is disposed between the illumination device and the color separation / synthesis device. According to this, the at least one lens becomes the most light incident side lens in the projection optical device, and the light modulation device can be arranged at the back focus position of the at least one lens. For this reason, since the distance between the at least one lens and the light modulation device can be shortened as compared with the configuration described in Patent Document 1, the dimension along the central axis of the projection optical device can be reduced. Therefore, the projector can be reduced in size.

In the above aspect, it is preferable that the lens disposed between the illumination device and the color separation / synthesis device includes a lens that collimates light incident from the illumination device.
According to the above aspect, the light that has passed through the polarization separation device passes through the lens that collimates the light incident from the illumination device included in the lens disposed between the illumination device and the color separation / synthesis device. Thus, the light incident on the color separation / synthesis device can be collimated. Accordingly, it is possible to suppress the spread of the light incident on the incident / exit surface, and the light can be reliably incident on the light modulation device, so that the light utilization efficiency can be increased. In addition, the light emitted from the incident / exit surface can be collected and incident on another lens constituting the projection optical apparatus.

In the one aspect, it is preferable that the illumination device includes a light source device and a polarization conversion element that aligns the emitted light emitted from the light source device with the first polarized light.
According to the above aspect, the first polarized light can be reliably incident on the polarization beam splitting device, so that the light use efficiency can be increased.

In the above aspect, the color separation / synthesis apparatus is preferably a dichroic prism including a plurality of prisms and a color separation layer.
According to the above aspect, the plurality of color lights incident on the dichroic prism are reliably separated by the plurality of prisms and the color separation layer, and the separated color lights are incident on the light modulation devices corresponding to the respective color lights. be able to. Further, since each color light can be separated and combined by one dichroic prism, the projector can be miniaturized.

In the one aspect, the three light modulation devices provided in accordance with each of the three color lights included in the emitted light are provided, and the dichroic prism is connected to a corresponding light modulation device among the three light modulation devices. Positioned between the first prism, the second prism, and the third prism that face each other, the first prism that has the incident / exit surface, and the second prism that faces the first prism, Among the three color lights included in the outgoing light incident on the first color light, the first color separation layer that separates the first color light, the second color light, and the third color light, the second prism, and the second color light The second color light is reflected between the second color light and the third color light which are located between the third prisms facing the prism and are incident on the second prism via the first color separation layer. The first A second color separation layer that transmits colored light, a gap is provided between the first color separation layer and the second prism, and the first prism and the first color separation layer There is no gap between the second color separation layer and the second color separation layer, and between the second color separation layer and the third prism. The incident angles of the two color lights are different from the incident angles of the second color light and the third color light with respect to the second color separation layer, and the incident angles of the three color lights to the first color separation layer are It is preferable that the incident angle of the second color light and the third color light to the second color separation layer is larger.

In such a dichroic prism, the light reflected by the first color separation layer is totally reflected by the top entry exit surface of the first prism and guided to the corresponding light modulation device. The light reflected by the second color separation layer is totally reflected inside the second prism at the surface of the second prism where a gap is formed between the first color separation layer and the second color separation layer. The light guided to the corresponding light modulation device and transmitted through the second color separation layer passes through the third prism and is guided to the corresponding light modulation device. For this reason, a gap formed between the first color separation layer and the second prism, which is difficult to control, is necessary.
However, when such a dichroic prism is adopted, each of the first color separation layer and the second color separation layer is compared with a case where a dichroic prism in which each color separation layer and each prism are combined with no gap is adopted. The incident angle can be reduced. Therefore, the color separation characteristics of each color separation layer can be improved.

In the one aspect, the three light modulation devices provided in accordance with each of the three color lights included in the emitted light are provided, and the dichroic prism is connected to a corresponding light modulation device among the three light modulation devices. Positioned between the first prism, the second prism, and the third prism that face each other, the first prism that has the incident / exit surface, and the second prism that faces the first prism, Among the three color lights included in the outgoing light incident on the first color light, the first color separation layer that separates the first color light, the second color light, and the third color light, the second prism, and the second color light The second color light is reflected between the second color light and the third color light which are located between the third prisms facing the prism and are incident on the second prism via the first color separation layer. The first A second color separation layer that transmits color light, between the first color separation layer and the second prism, between the first prism and the first color separation layer, and the second prism, There are no gaps between the second color separation layer and between the second color separation layer and the third prism, and the incident angles of the three color lights with respect to the first color separation layer, The incident angles of the second color light and the third color light to the second color separation layer are different from each other, and the incident angles of the three color lights to the first color separation layer are the second color separation layer. It is preferable that the incident angle of the second color light and the third color light is smaller than the incident angle.

In such a dichroic prism, the light reflected by the first color separation layer is totally reflected by the upper writing exit surface of the first prism and guided to the corresponding light modulation device in the same manner as described above. Further, the light reflected by the second color separation layer passes through the second prism and is guided to the corresponding light modulation device, and the light transmitted through the second color separation layer is the same as described above. The light passes through the third prism and is guided to the corresponding light modulation device. In such a dichroic prism, it is not necessary to provide the gap.

In the above aspect, it is preferable that the polarization separation device transmits the first polarized light and reflects the second polarized light included in the combined light toward a projection optical device.
Here, when the polarization beam splitting device is configured by a plate-type PBS, aberration may occur when modulated light passes through the tilted plate. On the other hand, according to the one aspect, the second polarized light modulated by the light modulation device reflects the plate of the polarization separation device, so that the first polarization is transmitted through the polarization separation device. Thus, the occurrence of the aberration can be suppressed.

1 is a schematic diagram showing an outline of a projector according to an embodiment of the invention. FIG. 4 is a diagram showing a back focus position of the projection optical apparatus in the projector according to the embodiment. The figure which shows the back focus position of the projection optical apparatus as a comparative example of the projection optical apparatus which concerns on the said embodiment, and the said projection optical apparatus. The schematic diagram which shows the deformation | transformation of the dichroic prism in the said embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Schematic configuration of projector]
FIG. 1 is a schematic diagram showing an outline of a projector 1 according to the present embodiment.
The projector 1 is a display device that modulates a light beam emitted from a light source provided therein to form an image according to image information, and enlarges and projects the image on a projection surface such as a screen. As shown in FIG. 1, the projector 1 includes an exterior housing 2 that constitutes an exterior.
An optical unit 3 is disposed inside the exterior housing 2. In addition, although not shown in the exterior casing 2, a cooling device that cools the components of the projector 1, a power supply device that supplies power to the components of the projector 1, and the operation of the projector 1 are controlled. A control device and the like are provided.

[Configuration of optical unit]
The optical unit 3 has a function of forming and projecting an image according to image information input from the control device. The optical unit 3 includes an illumination device 31, a relay device 32, a dichroic prism 34, a light modulation device 35 (35R, 35G, 35B), and a projection optical device 36.

[Configuration of lighting device]
The illumination device 31 includes a light source device 31 </ b> A and a uniform illumination device 31 </ b> B, and emits uniform illumination light having a uniform polarization direction to the relay device 32. The illumination light corresponds to the first polarized light of the present invention.
The light source device 31 </ b> A includes a solid light source device 311, a condensing optical system 312, a rotating fluorescent plate 313, and a motor 314.
The solid-state light source device 311 is a laser light source that emits blue laser light (emission intensity peak: about 445 nm) as excitation light. The solid light source device 311 may be composed of one laser light source, or may be composed of many laser light sources. Alternatively, a light source device that emits blue light having a wavelength other than 445 nm (for example, 460 nm) can be used.
The condensing optical system 312 includes a first lens 3121 and a second lens 3122. The condensing optical system 312 is disposed in the optical path from the solid-state light source device 311 to the rotating fluorescent plate 313, and makes the blue light incident on a phosphor layer 3132 (described later) of the rotating fluorescent plate 313 in a substantially condensed state. The first lens 3121 and the second lens 3122 are convex lenses.

In the rotating fluorescent plate 313, a phosphor layer 3132 that converts the wavelength of incident light is formed on a disc 3131 that can be rotated by a motor 314 along the circumferential direction of the disc 3131. The rotating fluorescent plate 313 emits red light and green light toward the side opposite to the side on which blue light is incident.
The disc 3131 is made of a material that transmits blue light. For example, quartz glass, crystal, sapphire, optical glass, and transparent resin can be used as the material of the disk 3131.

Blue light emitted from the solid state light source device 311 enters the phosphor layer 3132 from the disk 3131 side. A dichroic film 3133 that transmits blue light and reflects red light and green light is provided between the phosphor layer 3132 and the disk 3131.
The phosphor layer 3132 is excited by blue light having a wavelength of about 445 nm. The phosphor layer 3132 converts part of the blue light from the solid-state light source device 311 into light including red light and green light, and passes the remaining part of the blue light without conversion. The phosphor layer 3132 is, for example, a layer containing (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce that is a YAG phosphor.

In such a light source device 31 </ b> A, some of the blue light emitted from the solid-state light source device 311 passes through the phosphor layer 3132, and other light is red and green light by the phosphor layer 3132. Is converted into a wavelength. The phosphor layer 3132 scatters the wavelength-converted red light and green light, but the dichroic film 3133 prevents the light from proceeding to the solid light source device 311 side. These red light and green light are incident on the uniform illumination device 31B together with the blue light. The red light, green light, and blue light correspond to the first color light, the second color light, and the third color light of the present invention, respectively.

The uniform illumination device 31B equalizes the intensity distribution (illuminance distribution) in a plane orthogonal to the central axis of the light incident from the light source device 31A, and includes a collimating lens 315, a first lens array 316, and a second lens. An array 317, a polarization conversion element 318, and a superimposing lens 319 are included.
The collimating lens 315 is formed of a convex lens, and makes the light from the light source device 31A substantially parallel.
The first lens array 316 includes a plurality of first small lenses 3161 that divide the light from the collimating lens 315 into a plurality of partial light beams. The plurality of first small lenses 3161 are arranged in a matrix in a plane orthogonal to the illumination optical axis Ax (designed optical axis and the central axis of light emitted from the light source device 31A).
The second lens array 317 includes a plurality of second small lenses 3171 corresponding to the plurality of first small lenses 3161. The second lens array 317, together with the superimposing lens 319, forms an image of each first small lens 3161 of the first lens array 316 in the vicinity of the image forming area of each of the

light modulation devices

35R, 35G, and 35B. The plurality of second small lenses 3171 are arranged in a matrix in a plane orthogonal to the illumination optical axis Ax.

The polarization conversion element 318 has a function of aligning the polarization directions of the partial light beams divided by the first lens array 316.
Specifically, the polarization conversion element 318 transmits one of the linearly polarized components included in the light from the rotating fluorescent plate 313 as it is and reflects the other linearly polarized component in a direction perpendicular to the illumination optical axis Ax. A polarization separation layer that reflects the other linearly polarized light component reflected by the polarization separation layer in a direction parallel to the illumination optical axis Ax, and another linearly polarized light component reflected by the reflective layer. And a phase difference plate for converting into components. In the present embodiment, the polarization conversion element 318 is configured to emit p-polarized light, but may be configured to emit s-polarized light.

[Configuration of relay device]
The relay device 32 has a function of guiding the emitted light emitted from the illumination device 31 to the dichroic prism 34. The relay device 32 includes a total reflection mirror 321 and a polarization separation device 322.
The total reflection mirror 321 reflects the light incident from the illumination device 31 toward the polarization separation device 322.
The polarization separation device 322 is a so-called plate-type polarization beam splitter (PBS), which allows one of p-polarized light and s-polarized light to pass therethrough and reflects the other polarized light.
In the present embodiment, the polarization separation device 322 transmits p-polarized light (first polarized light) and reflects s-polarized light (second polarized light). For this reason, the light incident through the total reflection mirror 321 and the convex lens 366, that is, the light aligned with the p-polarized light by the polarization conversion element 318 passes through the polarization separation device 322 and is emitted to the dichroic prism 34. . On the other hand, the modulated light which is modulated by the light modulation device 35 described later and is incident through the dichroic prism 34 described later is reflected by the polarization separation device 322 and the lens 365 of the projection optical device 36 described later (see FIG. 2). ).

Here, a convex lens 366 is disposed between the polarization beam splitter 322 and the dichroic prism 34. As will be described in detail later, the convex lens 366 is one of the lenses of the projection optical device 36, and has a function of making the light incident from the polarization separation device 322 substantially parallel and incident on the dichroic prism 34.

[Configuration of dichroic prism]
The dichroic prism 34 separates the three color lights (red light, green light, and blue light) included in the light emitted from the illumination device 31 that is incident via the relay device 32 and the convex lens 366, and the

light modulation devices

35R and 35G. , 35B. The dichroic prism 34 has a function of synthesizing each color light incident after being modulated by the

light modulation devices

35R, 35G, and 35B and emitting the synthesized light (synthesized light). The dichroic prism 34 corresponds to the color separation / synthesis device of the present invention.
The dichroic prism 34 is a so-called gapless prism, and includes a first prism 341, a second prism 342, a third prism 343, and a first color separation layer 344 positioned between the first prism 341 and the second prism 342. And a second color separation layer 345 positioned between the second prism 342 and the third prism 343, and the prisms 341 to 343 are combined.

The dichroic prism 34 is provided between the first color separation layer 344 and the second prism 342, between the first prism 341 and the first color separation layer 344, and between the second prism 342 and the second color separation layer 345. , And the second color separation layer 345 and the third prism 343 are formed so as not to have any gaps. The dichroic prism 34 has an incident angle of three color lights (red light, blue light, and green light) to the first color separation layer 344 and an incidence angle of green light and blue light to the second color separation layer 345. The incident angles of the three color lights to the first color separation layer 344 are different from each other, and are configured to be larger than the incident angles of the green light and the blue light to the second color separation layer 345.

The first prism 341 is formed in a triangular prism shape, and is disposed at a position closest to the convex lens 366 among the prisms 341 to 343, that is, a position facing the convex lens 366. The first prism 341 has an incident / exit surface 3411 on which light collimated by the convex lens 366 is incident and the combined light is emitted. Further, the first prism 341 is joined to the second prism 342. Of the light incident between the first prism 341 and the second prism 342 via the incident / exit surface 3411, the first color separation layer 344 reflects red light and transmits green light and blue light. Is arranged.
The red light reflected by the first color separation layer 344 is incident on the incident / exit surface 3411 at an angle equal to or greater than the critical angle, and is emitted from the exit surface 3412 of the first prism 341 toward the light modulation device 35R.
Further, the blue light and green light transmitted through the first color separation layer 344 are incident on the second prism 342.

The second prism 342 is formed in a quadrangular prism shape with a substantially trapezoidal cross section, and is joined to the first prism 341 and the third prism 343. Between the second prism 342 and the third prism 343, the second color separation layer 345 that reflects blue light and transmits green light is disposed. The second color separation layer 345 and the first color separation layer 344 are inclined at different angles with respect to the central axis (illumination optical axis Ax) of light incident on the incident / exit surface 3411 via the convex lens 366. ing.
Of the blue light and green light incident on the second prism 342 via the first color separation layer 344, the blue light is reflected by the second color separation layer 345 and travels through the second prism 342. Then, the light is emitted from the emission surface 3421 of the second prism 342 toward the light modulation device 35B.
On the other hand, the green light incident on the second color separation layer 345 passes through the second color separation layer 345 and enters the third prism 343.

Similar to the second prism 342, the third prism 343 is formed in a quadrangular prism shape with a substantially trapezoidal cross section, and is joined to the second prism 342 as described above. The green light incident on the third prism 343 via the second color separation layer 345 is emitted from the emission surface 3431 which is located in the traveling direction of the green light and is substantially parallel to the incident / exit surface 3411. The light is emitted toward the modulation device 35G.
The color lights modulated by the

light modulation devices

35R, 35G, and 35B are combined by tracing back the incident paths of the color lights to the

light modulation devices

35R, 35G, and 35B. The combined light is emitted toward the convex lens 366.

[Configuration of light modulation device]
The light modulation device 35 (light modulation devices for red, green, and blue color lights are respectively referred to as 35R, 35G, and 35B) modulates incident red, green, and blue color lights, respectively, into image information. A corresponding color image is formed. These light modulation devices 35 (35R, 35G, 35B) are reflection type light modulation devices having a function of modulating incident light, and more specifically, have a function of modulating in the process of reflecting the light. In the present embodiment, these light modulation devices 35 (35R, 35G, and 35B) are configured by reflective liquid crystal panels, and emit red, blue, and green color light incident from the exit surfaces 3412, 3421, and 3431, respectively. Modulate.
Such

light modulation devices

35R, 35G, and 35B are disposed at the back focus positions of the projection optical device 36, respectively.

[Configuration of Projection Optical Device]
FIG. 2 is a diagram illustrating the configuration of the projection optical device 36 and the back focus position BF1 of the convex lens 366 constituting a part of the projection optical device 36. In FIG. 2, in order to facilitate the explanation of the back focus position BF1, the back focus position of green light (position of the light modulation device 35G) is shown, and the polarization separation device 322 is omitted, and the illumination light is shown. It is described that each component is located on a straight line along the axis Ax.
The projection optical device 36 has a function of projecting the combined light, which is image light reflected and incident by the polarization separation device 322, onto a projection surface (not shown). As shown in FIG. 2, the projection optical device 36 includes a plurality of

lenses

361, 362, 363, 364, and 365 accommodated in a lens barrel 360 (see FIG. 1), and the convex lens 366. . The actual projection optical apparatus is not limited to six lenses, and may have more lenses.

Here, the back focus position of the projection optical device 36 will be described.
As described above, the

light modulation devices

35R, 35G, and 35B are disposed at the back focus positions of the projection optical device 36, respectively. More specifically, each of the

light modulation devices

35R, 35G, and 35B is disposed at the back focus position BF1 of the lens that is located closest to the light incident side among the plurality of lenses that form the projection optical device 36.
Therefore, in this embodiment, the projection optical device 36 has a convex lens 366 positioned between the polarization separation device 322 and the dichroic prism 34 in addition to the lenses 361 to 365 in the lens barrel 360 in terms of lens design. Because of the configuration, each light modulation device 35 is arranged at the back focus position BF1 of the convex lens 366.

FIG. 3 is a diagram showing a projection optical apparatus 36A as a comparative example of the projection optical apparatus 36 and a back focus position BF2 of the projection optical apparatus 36A.
Here, a projection optical apparatus 36A as a comparative example of the projection optical apparatus 36 will be described.
As shown in FIG. 3, the projection optical device 36A has a lens barrel 360 and lenses 361 to 365 and 366A, as in the case of the projection optical device 36. However, all of these lenses 361 to 365 and 366A are in the lens barrel 360. The storage is arranged. Among these, the lens 366A has the same function as the convex lens 366. When such a projection optical device 36A is employed, even if a convex lens is disposed between the polarization separation device 322 and the dichroic prism 34, the convex lens is designed for the projection optical device 36A in terms of lens design. Not included.

The case where such a projection optical device 36A is employed is compared with the case where the projection optical device 36 according to the present embodiment is employed.
The distance L12 (the distance L12 from the most convex lens 366 on the light incident side to the back focus position BF1 of the projection optical device 36 (lens 366)) that is the back focus of the projection optical device 36 shown in FIG. 2 is the projection optical shown in FIG. The distance is shorter than the distance L22 (the distance L22 from the most incident lens 366A to the back focus position BF2 of the projection optical device 36A (lens 366A)) which is the back focus of the device 36A.
Therefore, the distance L11 from the lens 361 located closest to the light exit side in the projection optical device 36 shown in FIG. 2 to the convex lens 366 is the same as the lens 361 located closest to the light exit side in the projection optical device 36A shown in FIG. It is shorter than the distance L21 to the lens 366A located on the light incident side. That is, the projection optical device 36 can be configured as a projection optical device that has a shorter back focus and a smaller dimension in the direction along the central axis than the projection optical device 36A as a comparative example.

Specifically, Table 1 shows an example of a lens constituting the projection optical device 36, and Table 2 shows an example of a lens constituting a projection optical device 36A as a comparative example.

For example, in the configuration of the projection optical device 36 in which the lens (convex lens 366) positioned closest to the light incident side in the lens design is disposed between the polarization separation device 322 and the dichroic prism 34, as shown in Table 1, The lens with the number “4” has a radius of 49.5237, a surface separation of 39.763257, and an effective radius of 10.1706619. On the other hand, in the configuration of the projection optical device 36A, as shown in Table 2, the lens with surface number “4” has a radius of 102.77722, a surface interval of 76.890274, and an effective radius of 15.868343. Yes. Thus, in the projection optical device 36, the surface interval of each lens can be made smaller (substantially halved) than the surface interval of each lens constituting the projection optical device 36A. Therefore, as described above, the projection optical device 36 can be configured as a projection optical device having a small size in the direction along the central axis.

Further, for example, in the configuration of the projection optical device 36, as shown in Table 1, the lens having the surface number “1” has a radius of 121.69073, a surface interval of 1.734356, and an effective radius of 11.968877. On the other hand, in the configuration of the projection optical device 36A, as shown in Table 2, the lens with the surface number “1” has a radius of 258.222177, a surface interval of 1.734469, and an effective radius of 16.566122. Yes. Thus, in the projection optical device 36, the radius of each lens can be made smaller (approximately half) than the radius of each lens constituting the projection optical device 36A. Therefore, the projection optical device 36 can be configured as a projection optical device that is reduced in size in the radial direction of each lens.

[Effect of the embodiment]
The projector 1 of this embodiment has the following effects.
In the lens design, a convex lens 366 that is at least one of a plurality of lenses 361 to 366 constituting the projection optical device 36 is disposed between the polarization separation device 322 and the dichroic prism 34. According to this, the convex lens 366 becomes the most light incident side lens in the projection optical device 36, and the light modulation device 35 (35R, 35G, 35B) can be arranged at the back focus position of the convex lens 366. For this reason, since the distance between the convex lens 366 and the light modulation device 35 (35R, 35G, 35B) can be shortened as compared with the configuration described in Patent Document 1, the dimension along the central axis of the projection optical device 36 can be reduced. . Therefore, the projector 1 can be reduced in size.

Since the convex lens 366 disposed between the illumination device 31 and the dichroic prism 34 is disposed, the light that has passed through the polarization separation device 322 passes through the convex lens 366 and is incident on the dichroic prism 34. Can be parallelized. Accordingly, it is possible to suppress the spread of the light incident on the incident / exit surface 3411, and the light can be reliably incident on the light modulation device 35 (35R, 35G, 35B), so that the light utilization efficiency can be increased. . Further, the light emitted from the incident / exit surface 3411 can be collected and incident on other lenses 361 to 365 constituting the projection optical device 36. Furthermore, since the light modulation device 35 (35R, 35G, 35B) is constituted by a liquid crystal panel, the contrast can be improved by making each color light incident on the dichroic prism 34 in parallel.

The light emitted from the light source device 31A of the illumination device 31 can be converted into p-polarized light by the polarization conversion element 318, and the p-polarized light (first polarization) can be reliably incident on the polarization separation device 322. Use efficiency can be increased.

The plurality of color lights (red light, green light, and blue light) incident on the dichroic prism 34 are reliably transmitted by the plurality of prisms (first to third prisms 341 to 343) and the first and second color separation layers 344 and 345. The separated color lights can be incident on the light modulation devices 35 (35R, 35G, 35B) corresponding to the respective color lights. Further, since each color light can be separated and combined by one dichroic prism 34, the projector 1 can be miniaturized.

The dichroic prism 34 is configured by a so-called gapless prism, and the red light R reflected by the first color separation layer 344 is totally reflected by the incident / exit surface 3411 of the first prism 341, and the corresponding light modulation device. Guided to 35R. Further, the blue light B reflected by the second color separation layer 345 passes through the second prism 342, is guided to the corresponding light modulation device 35B, and is transmitted through the second color separation layer 345. G passes through the third prism 343 and is guided to the corresponding light modulation device 35G. In such a dichroic prism 34, between the first prism 341 and the first color separation layer 344, between the first color separation layer 344 and the second prism 342, and between the second prism 342 and the second color separation layer 345, And there is no gap between the second color separation layer and the third prism 343. For this reason, the dichroic prism 34 does not require a gap that is required when it is configured by a so-called Philips prism.

Since the polarization beam splitter 322 is a plate-type PBS, aberration may occur when modulated light (second polarized light) passes through the tilted plate. On the other hand, according to the present embodiment, since the s-polarized light (second polarized light) modulated by the light modulation device 35 reflects the plate of the polarization separation device 322, the polarization separation device 322 is made p-polarization ( The occurrence of the aberration can be suppressed compared to the case where the first polarized light) is transmitted.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In the above embodiment, the dichroic prism 34 is constituted by a so-called gapless prism. However, the present invention is not limited to this. For example, the dichroic prism 34 may be configured by a Philips prism.

FIG. 4 is a schematic diagram showing a dichroic prism 37 composed of a Philips prism.
As shown in FIG. 4, the dichroic prism 37 composed of the Philips prism is similar to the dichroic prism 34 composed of the gapless prism, as shown in FIG. 4, and the first color 371, the second prism 372, the third prism 373, and the first color. A separation layer 374 and a second color separation layer 375, and the prisms 371 to 373 are combined.

Similar to the first prism 341, the first prism 371 is formed in a substantially triangular prism shape, and is disposed at a position closest to the polarization separation device 322 among the first to third prisms 371 to 373. The first prism 371 has an incident / exit surface 3711 orthogonal to the illumination optical axis Ax, and light that has passed through the polarization separation device 322 enters the first prism 371 through the incident / exit surface 3711.
A first color separation layer 374 is disposed between the first prism 371 and the second prism 372 joined to the first prism 371 so as to be inclined with respect to the illumination optical axis Ax. Yes. Specifically, the first color separation layer 374 is formed on the surface of the first prism 371 opposite to the incident / exit surface 3711.

Similar to the first color separation layer 344, the first color separation layer 374 reflects light of a predetermined threshold value or more and transmits light of other wavelengths.
For example, when the first color separation layer 374 is configured to reflect the blue light B and transmit the green light G and the red light R out of the incident light, the first color separation layer 374 reflects the first light. The blue light B is incident on the incident / exit surface 3711 from the inside of the first prism 371 at an angle greater than the critical angle. Then, the blue light B is incident from the emission surface 3712 of the first prism 371 to the blue light light modulation device 35B (not shown) facing the emission surface 3712.
On the other hand, the green light G and the red light R incident on the first color separation layer 374 pass through the first color separation layer 374 and are further formed between the first prism 371 and the second prism 372. It passes through the gap GP and enters the second prism 372.

The second prism 372 is formed in a substantially triangular prism shape, and is disposed between the first prism 371 and a gap GP of about several μm. A second color separation layer 375 is disposed between the second prism 372 and the third prism 373 so as to be inclined to the opposite side of the first color separation layer 374 with respect to the illumination optical axis Ax. ing.
Similar to the second color separation layer 345, the second color separation layer 375 has a threshold value different from or different from that of the first color separation layer 374 out of light incident from the first prism 371 through the gap GP. Reflects light and transmits light of other wavelengths.
For example, when the second color separation layer 375 is configured to reflect the red light R and transmit the green light G out of the incident green light G and red light R, the second color separation layer 375. The red light R reflected by the light enters the end surface 3721 facing the first prism 371 from the inside of the second prism 372 at an angle greater than the critical angle. Then, the red light R enters the light modulation device 35R (not shown) for red light that faces the emission surface 3722 from the emission surface 3722 of the second prism 372.
On the other hand, the green light G that has passed through the second color separation layer 375 enters the third prism 373 that is joined to the second prism 372 without any gap.

The third prism 373 is formed in a quadrangular prism shape with a substantially trapezoidal cross section. The third prism 373 has an exit surface 3731 parallel to the incident / exit surface 3711, that is, an exit surface 3731 orthogonal to the illumination optical axis Ax, on the side opposite to the surface on which light is incident from the second prism 372. . Then, the green light G incident on the third prism 373 enters the light modulator 35G (not shown) for green light facing the emission surface 3731 from the emission surface 3731.
Then, the color lights B, G, R modulated by the

light modulation devices

35B, 35G, 35R follow the incident paths of the color lights B, G, R to the

light modulation devices

35B, 35G, 35R in reverse. And is emitted from the incident / exit surface 3711 toward the polarization separation device 322 as synthesized light.

Also in such a dichroic prism 37, the first color separation layer 374 and the second color separation layer 375 intersect the illumination optical axis Ax at different angles, respectively, and light of each

color separation layer

374, 375 is transmitted. The incident angles are also different.
For example, the first color separation layer 374 is inclined so that the incident angle of light incident along the illumination optical axis Ax is −28 °, whereas the second color separation layer 375 It is inclined so that the incident angle of light incident along the optical axis Ax is + 11 °.
For this reason, even when the dichroic prism 37 composed of a Philips prism is employed, the first color separation layer 374 and the second color separation layer are formed as in the case where the dichroic prism 34 composed of a gapless prism is employed. 375 has different color separation characteristics for each type of incident linearly polarized light.

Even when such a dichroic prism 37 is used in a projector instead of the dichroic prism 34, the incident angle of light to each of the color separation layers 374 and 375 and the illumination device 31 (specifically, a light source device) used in the projector. By setting the color light separated by the first color separation layer 374 and the second color separation layer 375 based on the wavelength distribution of the emitted light by 31A), the same effect as the projector 1 can be obtained. .

Incidentally, in the dichroic prism 37 constituted by the Philips prism, it is necessary to dispose the gap GP of about several μm, but the light reflected by the second color separation layer 375 is reflected by the second prism 372. Since the inner surface is reflected by the surface facing one prism 371 and guided to the corresponding light modulation device 35, the incident angle of the light incident on the color separation layer is determined in the dichroic prism 34 formed by the gapless prism. The incident angle to the large second color separation layer 345 can be reduced. Therefore, the dichroic prism 37 has better color separation characteristics than the dichroic prism 34.
On the other hand, the dichroic prism 34 does not require adjustment of the gap GP required by the dichroic prism 37 as described above.

In the above embodiment, the dichroic prism 34 is constituted by a so-called gapless prism. However, the present invention is not limited to this. For example, the dichroic prism 34 may be configured by a cross dichroic prism.

In the above embodiment, the lens located closest to the light incident side of the projection optical device 36 is configured by the convex lens 366. However, the present invention is not limited to this. For example, a concave lens may be used. Even in this case, since the distance L12 can be reduced, the distance L11 (dimension) in the direction along the central axis of the light emitted from the light source device of the projection optical device 36 can be reduced.

In the above embodiment, the reflection type light modulation device 35 (35R, 35G, 35B) is used as the light modulation device, and the light separated by the dichroic prism 34 is modulated and reflected. However, the present invention is not limited to this. For example, instead of the light modulation device 35 (35R, 35G, 35B), a transmission type light modulation device may be used. In this case, a configuration that transmits the transmissive light modulator and emits the modulated light again to the dichroic prism 34 may be provided in the vicinity of the transmissive light modulator.

In the above embodiment, the solid-state light source device 311 of the illumination device 31 is configured by a laser light source that emits blue light. However, the present invention is not limited to this. For example, it is good also as replacing with the solid light source device 311 of the illuminating device 31, and providing a light source lamp and a reflector. In this case, since the light emitted from the light source lamp and the reflector includes red, green, and blue, the rotating fluorescent plate 313 and the motor 314 need not be provided.

In the said embodiment, although the optical unit 3 was comprised by the substantially L shape, this invention is not limited to this. For example, you may employ | adopt the optical unit comprised by the substantially U shape.
In the above embodiment, the projector 1 includes the three light modulation devices 35 (35R, 35G, and 35B), but the present invention is not limited to this. That is, the present invention can also be applied to a projector using two or less or four or more light modulation devices.
In addition, as long as the light modulation device can modulate an incident light beam and form an image according to image information, a device using a micromirror, for example, a device using a DMD (Digital Micromirror Device) or the like can be used. A light modulation device may be used.

DESCRIPTION OF SYMBOLS 1 ... Projector, 31A ... Light source device, 311 ... Solid light source device, 318 ... Polarization conversion element, 322 ... Polarization separation device, 366 ... Convex lens (parallelizing lens), 34, 37 ... Dichroic prism (color separation / synthesis device), 341 , 371 ... 1st prism, 342, 372 ... 2nd prism, 343, 373 ... 3rd prism, 344, 374 ... 1st color separation layer, 345, 375 ... 2nd color separation layer, 3411, 3711 ... entrance / exit surface , 35, 35R, 35G, 35B ... light modulation device, 36, 36A ... projection optical device, 361, 362, 363, 364, 365, 366A ... lens, Ax ... illumination optical axis, BF1 ... back focus position, BF2 ... back Focus position.

Claims

An illumination device for emitting the first polarized light;
A plurality of light modulation devices that are provided according to each of a plurality of color lights included in the emitted light emitted by the illumination device, and respectively modulate the plurality of color lights;
The plurality of color lights are arranged between the illumination device and the plurality of light modulation devices, and separated from the emitted light incident on the inside through an incident / exit surface, and respectively incident on the plurality of light modulation devices. A color separation / synthesis device that emits, through the incident / exit surface, combined light obtained by combining the plurality of color lights that are modulated and incident by the plurality of light modulation devices;
A polarization separation device that is disposed between the illumination device and the color separation / synthesis device, transmits one of the first polarization and the second polarization orthogonal to the first polarization, and reflects the other;
A projection optical device that projects the combined light emitted from the polarization separation device,
The projection optical device has a plurality of lenses,
At least one lens among the plurality of lenses is disposed between the illumination device and the color separation / synthesis device.
The projector according to claim 1.
The projector is characterized in that the lens disposed between the illumination device and the color separation / synthesis device includes a lens that collimates light incident from the illumination device.
The projector according to claim 1 or 2,
The lighting device includes:
A light source device;
A projector comprising: a polarization conversion element that aligns outgoing light emitted from the light source device with first polarized light.
In the projector as described in any one of Claims 1-3,
The color separation / synthesis apparatus includes:
A projector comprising a dichroic prism including a plurality of prisms and a color separation layer.
The projector according to claim 4,
Including three of the light modulation devices provided according to each of the three color lights included in the emitted light,
The dichroic prism is
Of the three light modulation devices, a first prism, a second prism, and a third prism respectively facing the corresponding light modulation device;
Of the three color lights included in the outgoing light that is located between the first prism having the incident / exit surface and the second prism facing the first prism and is incident on the first prism A first color separation layer that separates the first color light from the second color light and the third color light;
The second color light and the third color light which are located between the second prism and the third prism facing the second prism and are incident on the second prism via the first color separation layer. A second color separation layer that reflects the second color light and transmits the third color light,
A gap is provided between the first color separation layer and the second prism,
Between the first prism and the first color separation layer, between the second prism and the second color separation layer, and between the second color separation layer and the third prism, respectively. There is no gap
The incident angles of the three color lights with respect to the first color separation layer and the incident angles of the second color light and the third color light with respect to the second color separation layer are different from each other and to the first color separation layer. An incident angle of the three color lights is greater than an incident angle of the second color light and the third color light to the second color separation layer.
The projector according to claim 4,
Including three of the light modulation devices provided according to each of the three color lights included in the emitted light,
The dichroic prism is
Of the three light modulation devices, a first prism, a second prism, and a third prism respectively facing the corresponding light modulation device;
Of the three color lights included in the outgoing light that is located between the first prism having the incident / exit surface and the second prism facing the first prism and is incident on the first prism A first color separation layer that separates the first color light from the second color light and the third color light;
The second color light and the third color light which are located between the second prism and the third prism facing the second prism and are incident on the second prism via the first color separation layer. A second color separation layer that reflects the second color light and transmits the third color light,
Between the first color separation layer and the second prism, between the first prism and the first color separation layer, between the second prism and the second color separation layer, and the second There are no gaps between the color separation layer and the third prism,
The incident angles of the three color lights with respect to the first color separation layer and the incident angles of the second color light and the third color light with respect to the second color separation layer are different from each other and to the first color separation layer. An incident angle of the three color lights is smaller than incident angles of the second color light and the third color light to the second color separation layer.
The projector according to any one of claims 1 to 6,
The projector according to claim 1, wherein the polarization separation device transmits the first polarized light and reflects the second polarized light included in the combined light toward a projection optical device.