JP2014170095A - Projector - Google Patents

Abstract

A projector capable of projecting an image with improved contrast ratio and brightness is provided.
A projector includes an illumination device that emits R light, G light, and B light with a polarization direction aligned in a predetermined direction, and a spatial light modulation device 320 that modulates R light, G light, and B light, respectively. A sub-spatial light modulation device 310 that adjusts the amount of light by modulating incident color light; and the R light and B light emitted from the first spatial light modulation device 320R and the third spatial light modulation device 320B; A cross dichroic prism 400 that combines three color lights by transmitting the G light emitted from the second spatial light modulator 320G, and a projection optical device that projects the light combined by the cross dichroic prism 400. The R light and B light incident on the cross dichroic prism 400 are first polarized light, and the G light incident on the cross dichroic prism 400 is second polarized light. It is.
[Selection] Figure 2

Description

  The present invention relates to a projector.

  2. Description of the Related Art Conventionally, there is known a projector including a light source, a light modulation device that modulates light emitted from the light source, and a projection lens that projects the modulated light. Incidentally, in recent years, there has been a demand for a high contrast ratio of a projected image. To achieve this high contrast ratio, a projector (projection type) provided with a light control means for adjusting the amount of light on the upstream side of the optical path of the light modulator. Display devices) have been proposed (see, for example, Patent Document 1).

The projector described in Patent Document 1 includes a color separation unit that separates light emitted from a light source into a plurality of color lights, a light modulation unit that modulates the plurality of separated color lights, and a color that combines the modulated color lights. The image forming apparatus includes a combining unit, a projecting unit that projects the combined light, and a dimming unit that includes a liquid crystal panel or the like.
The light control means is disposed between the light modulation means and the color separation means for each color light, and is configured to adjust the amount of each color light to be transmitted based on information from the outside. Then, each color light whose light quantity has been adjusted is modulated by the light modulation means, synthesized by the color synthesis means, and projected by the projection means.

JP 2003-186107 A

  However, in the projector described in Patent Document 1, the contrast ratio of the projected image is improved by adjusting the light amount of the separated color light, but the light from the color separation means to the projection means is improved. When colored light is reflected or transmitted by an optical component on the road, a lossy component may occur, and the projected image may not be bright enough to exhibit the ability of the light source.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A projector according to this application example includes a light source, an illumination device that emits first color light and second color light belonging to each wavelength region with a polarization direction aligned in a predetermined direction, and A first spatial light modulation device that modulates the first color light; a second spatial light modulation device that modulates the second color light; the first spatial light modulation device; and the second spatial light modulation. A sub-spatial light modulation device that is arranged on at least one light incident side or light emission side of the device and adjusts the amount of light emitted by modulating incident color light, and is emitted from the first spatial light modulation device A first reflective film that reflects the first color light and transmits the second color light emitted from the second spatial light modulator; and the first spatial light modulator and Combines each color light modulated by the second spatial light modulator And a projection optical device that projects the light synthesized by the color synthesis optical device, and the first color light incident on the color synthesis optical device has a first polarization direction. The second color light incident on the color synthesis optical device is second polarization light having a second polarization direction orthogonal to the first polarization direction. .

According to this configuration, the sub-spatial light modulation device is arranged on at least one light incident side or light emission side of the first spatial light modulation device and the second spatial light modulation device. By adjusting the amount of color light emitted from the apparatus, the contrast ratio of the projected image can be improved, that is, the brightness range (dynamic range) of the image that can be displayed can be expanded.
The color combining optical device reflects the first color light of the first polarized light and transmits the second color light of the second polarized light to combine the two color lights. Accordingly, a dielectric multilayer film or the like having a higher reflectance in a wider wavelength region than the second polarized light is used as the first reflective film with respect to the first polarized light. The modulated color light can be used efficiently.
Therefore, the projector can project an image with an improved contrast ratio and brightness, and can realize an image projection with high image quality and excellent compatibility with the use environment.
Here, the term “spatial light modulator” is a term including a transmissive or reflective light valve. In the present invention, the “sub” that modifies the “spatial light modulation device” is simply a term used to clarify the distinction of the “spatial light modulation device” in terms of words. It has no meaning other than distinguishing it from others.

  Application Example 2 In the projector according to the application example described above, the sub spatial light modulation device includes a first sub spatial light modulation device that adjusts a light amount by modulating the first color light, and the second color light. It is preferable to include a second sub spatial light modulation device that adjusts the amount of light by modulating.

  According to this configuration, since the sub spatial light modulation device is provided corresponding to each of the two color lights, the projector adjusts the light amounts of the two color lights emitted from the illumination device, and the projector further increases the contrast ratio. The projected image can be projected.

  Application Example 3 In the projector according to the application example, the first sub spatial light modulation device and the second sub spatial light modulation device include a liquid crystal panel that modulates incident light, and light incidence of the liquid crystal panel. The first sub spatial light modulation device and the third sub spatial light modulation device, comprising: an incident side polarizing plate disposed on a side; and an emission side polarizing plate disposed on a light emission side of the liquid crystal panel. The incident-side polarizing plate and the emitting-side polarizing plate are arranged so as to have either a parallel Nicols arrangement or a crossed Nicols arrangement, and the incident-side polarizing plate and the emitting-side polarizing plate in the second sub spatial light modulator. Is preferably arranged to be the other of the parallel Nicol arrangement and the crossed Nicol arrangement.

  According to this configuration, the direction of the transmission axis of the exit side polarizing plate with respect to the transmission axis of the incident side polarizing plate is different between the first sub spatial light modulation device and the second sub spatial light modulation device. Two color lights whose polarization directions are emitted from a predetermined direction can be converted into desired polarization directions and incident on the color combining optical device. That is, the first color light emitted from the illumination device is easily incident on the color synthesis optical device as the first polarized light, and the second color light is incident on the color synthesis optical device as the second polarization light. Can do.

  Application Example 4 In the projector according to the application example, the projector includes a retardation plate that converts one of the incident first polarized light and the second polarized light into the other, and the retardation plate is the first retardation plate. It is preferable that the light source is disposed between the illumination device and the color combining optical device on an optical path of at least one of the second color light and the second color light.

  According to this configuration, the retardation plate can easily convert the polarization direction of the light emitted from the illumination device, the spatial light modulation device, and the sub spatial light modulation device. It can be easily configured so that the first color light becomes the first polarized light and the second color light incident on the color synthesis optical device becomes the second polarized light. That is, the freedom degree of a structure of an illuminating device, a spatial light modulator, and a subspatial light modulator can be expanded.

  Application Example 5 In the projector according to the application example, the projector includes a retardation plate that converts one of the incident first polarized light and the second polarized light into the other, and the retardation plate is the first retardation plate. Arranged between the illumination device and the color synthesizing optical device on the optical path of any one of the color light and the second color light, and the first spatial light modulation device, the second spatial light modulation device, The first sub spatial light modulator and the second sub spatial light modulator include a liquid crystal panel that modulates incident light, an incident-side polarizing plate disposed on a light incident side of the liquid crystal panel, An exit-side polarizing plate disposed on the light exit side of the liquid crystal panel, and the first spatial light modulator, the second spatial light modulator, the first sub spatial light modulator, and the In each of the second sub spatial light modulators Takes the incident side polarization plate and the irradiation-side polarization plate, it is preferably arranged such that either the parallel Nicol arrangement and a cross-Nicol arrangement.

  According to this configuration, the first spatial light modulation device, the second spatial light modulation device, the first sub spatial light modulation device, and the incident side polarization plate and the emission side polarization plate of the second sub spatial light modulation device The first color light incident on the color combining optical device becomes the first polarized light by the phase difference plate and is incident on the color combining optical device while unifying the arrangement with the parallel Nicol arrangement or the crossed Nicol arrangement. The polarization direction of the light can be easily converted so that the second color light to be converted into the second polarized light. The arrangement of the incident side polarizing plate and the emitting side polarizing plate of the first spatial light modulation device, the second spatial light modulation device, the first sub spatial light modulation device, and the second sub spatial light modulation device is uniform. Therefore, the control method of the first spatial light modulation device, the second spatial light modulation device, the first sub spatial light modulation device, and the second sub spatial light modulation device can be simplified.

  Application Example 6 In the projector according to the application example, it is preferable that the first polarized light is s-polarized light, and the second polarized light is p-polarized light.

  According to this configuration, the dielectric multilayer film having a higher reflectance in a wider wavelength region than that of p-polarized light with respect to s-polarized light is used as the first reflective film. The modulated color light can be used efficiently. Therefore, the projector can project an image with an improved contrast ratio and brightness, and can realize an image projection with high image quality and excellent compatibility with the use environment.

FIG. 2 is a schematic diagram illustrating a schematic configuration of an optical system in the projector according to the first embodiment. 1 is a schematic diagram illustrating an electro-optical device and a cross dichroic prism according to a first embodiment. The schematic diagram which shows the 1st sub spatial light modulation apparatus and 3rd sub spatial light modulation apparatus of 1st Embodiment. The schematic diagram which shows the 2nd sub spatial light modulation apparatus of 1st Embodiment. The graph which shows the spectral reflectance characteristic of the 1st reflective film in 1st Embodiment, and a 2nd reflective film. FIG. 9 is a schematic diagram illustrating an electro-optical device and a cross dichroic prism according to a second embodiment. FIG. 10 is a schematic diagram illustrating an electro-optical device and a cross dichroic prism according to a third embodiment. FIG. 9 is a schematic diagram illustrating a modified electro-optical device and a cross dichroic prism.

(First embodiment)
Hereinafter, the projector according to the first embodiment will be described with reference to the drawings.
The projector according to the present embodiment modulates light emitted from a light source according to image information, and projects the modulated light onto a projection surface such as a screen.
[Configuration of projector optical system]
FIG. 1 is a schematic diagram illustrating a schematic configuration of an optical system in the projector 1000 according to the present embodiment.
As shown in FIG. 1, the optical system of the projector 1000 includes an illumination device 10, an electro-optical device 300, a cross dichroic prism 400 as a color synthesizing optical device, and a projection lens 500 as a projection optical device. These optical components are held in an optical component casing (not shown).

The illumination device 10 includes an integrator illumination system 100 and a color separation optical system 200.
The integrator illumination system 100 includes a light source 110 that emits substantially parallel light, a first lens array 120, a second lens array 130, a polarization conversion element 140 as polarization conversion means, and a superimposing lens 150. .

  The light source 110 includes an arc tube that emits light and a reflector that reflects light from the arc tube in a predetermined direction, and emits the light toward the first lens array 120. The first lens array 120 includes a plurality of small lenses, and divides the light from the light source 110 into a plurality of partial light beams. The second lens array 130 and the superimposing lens 150 collect a plurality of partial light beams from the first lens array 120, and form an image formation area of a later-described spatial light modulation device 320 of the electro-optical device 300 that is an illuminated area. The image formation area is illuminated with substantially uniform brightness. The polarization conversion element 140 disposed between the second lens array 130 and the superimposing lens 150 includes a polarization separation film and a phase difference plate, and emits light having a random polarization direction emitted from the light source 110 in a predetermined direction. The light is emitted in line with the polarized light. The polarization conversion element 140 of the present embodiment is configured to emit s-polarized light.

  The color separation optical system 200 includes dichroic mirrors 210 and 220, reflection mirrors 230, 240, and 250, relay lenses 260 and 270, and field lenses 280R, 280G, and 280B, and white light emitted from the integrator illumination system 100. The light is red light (hereinafter referred to as “R light”) as the first color light, green light (hereinafter referred to as “G light”) as the second color light, and blue light (hereinafter referred to as “B light” as the third color light). ”). Here, the reflection mirrors 240 and 250 and the relay lenses 260 and 270 are relay optical systems.

  The dichroic mirror 210 reflects R light among white light emitted from the integrator illumination system 100 and transmits G light and B light. The dichroic mirror 220 reflects G light and transmits B light among the light transmitted through the dichroic mirror 210.

The R light separated by the dichroic mirror 210 is reflected by the reflection mirror 230, and enters the first sub spatial light modulation device 310R (described later) of the electro-optical device 300 via the field lens 280R.
The G light reflected by the dichroic mirror 220 passes through a field lens 280G and enters a second sub spatial light modulation device 310G (to be described later) of the electro-optical device 300.
Then, the B light transmitted through the dichroic mirror 220 is incident on a later-described third sub spatial light modulator 310B of the electro-optical device 300 via the relay lenses 260 and 270, the reflection mirrors 240 and 250, and the field lens 280B. .

  As described above, the illumination device 10 includes the light belonging to the wavelength range of the R light (first color light), the light belonging to the wavelength range of the G light (second color light), and the B light aligned with the s-polarized light. The light (third color light) belonging to the wavelength region is emitted. The optical system of the present embodiment is configured such that the B light is guided to the electro-optical device 300 by a relay optical system, but is not limited thereto, and for example, the R light or the G light is a relay optical system and the electro-optical device 300. It is good also as a structure led to.

  The electro-optical device 300 includes a sub spatial light modulation device 310 and a spatial light modulation device 320 provided for R light, G light, and B light, respectively. The sub spatial light modulators 310R, 310R, 310G, and 310B provided for the R light, G light, and B light, respectively, are used as the first sub spatial light modulator 310R, the second sub spatial light modulator 310G, and the third sub spatial light modulator 310B. And The spatial light modulators 320 respectively provided for the R light, G light, and B light are referred to as a first spatial light modulator 320R, a second spatial light modulator 320G, and a third spatial light modulator 320B. .

The sub spatial light modulator 310 adjusts the amount of light transmitted by modulating the color light emitted from the illumination device 10. The spatial light modulation device 320 modulates the color light emitted from the sub spatial light modulation device 310 according to the image information to form a display image.
As will be described in detail later, the electro-optical device 300 performs R light (first color light) and B light (third color light) of the first polarized light having the first polarization direction with respect to the cross dichroic prism 400. ) And the G light (second color light) of the second polarized light having the second polarization direction orthogonal to the first polarization direction. In the present embodiment, the s-polarized light corresponds to the first polarized light, and the p-polarized light corresponds to the second polarized light.

As shown in FIG. 1, the cross dichroic prism 400 has a substantially square shape in a top view in which four right angle prisms are bonded together, and a dielectric multilayer on the interface in a substantially X shape in a top view in which right angle prisms are bonded together. A first reflective film 401 and a second reflective film 402 formed of a film are provided.
In the cross dichroic prism 400, the first reflective film 401 of the dielectric multilayer film reflects the R light modulated by the first spatial light modulator 320R, and the third spatial light modulator 320B and the second spatial light are reflected. The B light and G light modulated by the modulation device 320G are transmitted, the second reflective film 402 of the dielectric multilayer film reflects the B light modulated by the third spatial light modulation device 320B, and the first The R light and G light modulated by the spatial light modulation device 320R and the second spatial light modulation device 320G are transmitted to synthesize each color light. The cross dichroic prism 400 will be described in detail later.

  The projection lens 500 includes a plurality of lenses (not shown), and enlarges and projects the light combined by the cross dichroic prism 400 onto a projection surface such as a screen.

[Configuration of electro-optical device]
Here, the electro-optical device 300 will be described in detail.
FIG. 2 is a schematic diagram showing the electro-optical device 300 and the cross dichroic prism 400.
As described above, the electro-optical device 300 includes the sub spatial light modulator 310 (the first sub spatial light modulator 310R, the second sub spatial light modulator 310G, and the third sub spatial light modulator 310B), and Spatial light modulators 320 (first spatial light modulator 320R, second spatial light modulator 320G, and third spatial light modulator 320B) are provided.

First, the sub spatial light modulator 310 will be described.
As shown in FIG. 2, the first sub-spatial light modulation device 310R includes a liquid crystal panel 312R, an incident-side polarizing plate 311R and an emission-side polarizing plate 313R arranged on the light incident side and the light emitting side of the liquid crystal panel 312R, respectively. Is provided.
The second sub-spatial light modulation device 310G includes a liquid crystal panel 312G, and an incident-side polarizing plate 311G and an emitting-side polarizing plate 313G arranged on the light incident side and the emission side of the liquid crystal panel 312G, respectively.
The third sub spatial light modulator 310B includes a liquid crystal panel 312B, and an incident side polarizing plate 311B and an emission side polarizing plate 313B arranged on the light incident side and the emission side of the liquid crystal panel 312B, respectively.

  The incident side polarizing plates 311R, 311G, and 311B transmit the s-polarized light emitted from the illumination device 10, absorb the polarized light different from the s-polarized light, and emit it to the liquid crystal panels 312R, 312G, and 312B.

The liquid crystal panels 312R, 312G, and 312B are configured, for example, of a TN (Twist Nematic) type, and are configured by sealing liquid crystal between a pair of transparent glass substrates. The liquid crystal panels 312R, 312G, and 312B have a rectangular pixel region (not shown), and a plurality of pixels are formed in a matrix in the pixel region. The number of pixels of the liquid crystal panels 312R, 312G, and 312B is much smaller than the liquid crystal panels 322R, 322G, and 322B described later of the spatial light modulator 320 (for example, the number of pixels of 4 × 4).
In the liquid crystal panels 312R, 312G, and 312B, the alignment state of the liquid crystal is controlled according to a drive signal from a control unit (not shown), and each color light emitted from the incident side polarizing plates 311R, 311G, and 311B is output according to image information. Modulate.

The exit-side polarizing plates 313R, 313G, and 313B transmit polarized light in a certain direction out of the light emitted from the liquid crystal panels 312R, 312G, and 312B, and absorb polarized light different from the polarized light to absorb the spatial light modulator 320. To ejaculate.
The exit side polarizing plates 313R and 313B and the exit side polarizing plate 313G are arranged so that the directions of the transmission axes are different.

FIG. 3 is a schematic diagram showing the first sub spatial light modulator 310R and the third sub spatial light modulator 310B. FIG. 4 is a schematic diagram showing the second sub spatial light modulator 310G.
As shown in FIG. 3, the exit side polarization plates 313R and 313B in the first sub spatial light modulation device 310R and the third sub spatial light modulation device 310B are incident side polarized light arranged so as to transmit s-polarized light. The plates 311R and 311B are disposed so as to transmit p-polarized light. That is, the incident side polarization plates 311R and 311B and the emission side polarization plates 313R and 313B in the first sub spatial light modulation device 310R and the third sub spatial light modulation device 310B are crosses whose transmission axes are substantially perpendicular to each other. Nicole arrangement.

On the other hand, the exit-side polarizing plate 313G in the second sub-spatial light modulation device 310G, as shown in FIG. 4, transmits s-polarized light in the same manner as the incident-side polarizing plate 311G arranged to transmit s-polarized light. It arrange | positions so that it may permeate | transmit. That is, the incident-side polarizing plate 311G and the emission-side polarizing plate 313G in the second sub spatial light modulation device 310G have a parallel Nicol arrangement in which the directions of the transmission axes are the same.
Thus, the incident side polarizing plates 311R and 311B and the exit side polarizing plates 313R and 313B in the first sub spatial light modulation device 310R and the third sub spatial light modulation device 310B are configured in a crossed Nicols arrangement. On the other hand, the incident side polarizing plate 311G and the emission side polarizing plate 313G in the second sub spatial light modulation device 310G are configured in a parallel Nicol arrangement.

  The first sub spatial light modulation device 310R, the second sub spatial light modulation device 310G, and the third sub spatial light modulation device 310B are connected to the pixel electrodes of the liquid crystal panels 312R, 312G, and 312B based on the drive signal from the control unit. The amount of color light to be transmitted is adjusted by changing the magnitude of the voltage applied every time.

Specifically, when the voltage applied to the pixel electrode is low, the liquid crystal panels 312R, 312G, and 312B convert most of the incident s-polarized light into p-polarized light in the region corresponding to the pixel electrode, and the pixel electrode When the voltage applied to is high, most of the incident s-polarized light remains as s-polarized light in the region corresponding to the pixel electrode.
Accordingly, in the first sub spatial light modulator 310R and the third sub spatial light modulator 310B, the lower the voltage applied to the liquid crystal panels 312R and 312B, the more incident color light is transmitted, and the second In the sub spatial light modulation device 310G, the higher the voltage applied to the liquid crystal panel 312G, the more incident color light is transmitted.

  As described above, the sub spatial light modulation device 310 adjusts the amount of light to be transmitted corresponding to the pixel electrode, and the first sub spatial light modulation device 310R emits R light of p-polarized light, and the second The sub spatial light modulator 310G emits G light of s-polarized light, and the third sub spatial light modulator 310B emits B light of p-polarized light.

Next, the spatial light modulator 320 will be described.
Returning to FIG. 2, the first spatial light modulation device 320R includes a liquid crystal panel 322R, and an incident-side polarizing plate 321R and an emitting-side polarizing plate 323R arranged on the light incident side and the emission side of the liquid crystal panel 322R, respectively.
The second spatial light modulation device 320G includes a liquid crystal panel 322G, and an incident-side polarizing plate 321G and an emission-side polarizing plate 323G disposed on the light incident side and the emission side of the liquid crystal panel 322G, respectively.
The third spatial light modulator 320B includes a liquid crystal panel 322B, and an incident side polarizing plate 321B and an emission side polarizing plate 323B arranged on the light incident side and the emission side of the liquid crystal panel 322B, respectively.

The liquid crystal panels 322R, 322G, and 322B are formed of, for example, a TN type, and have a configuration in which liquid crystal is hermetically sealed between a pair of transparent glass substrates. The liquid crystal panels 322R, 322G, and 322B have a rectangular pixel region in which minute pixels (not shown) are formed in a matrix, and the alignment state of the liquid crystal corresponding to each minute pixel according to a drive signal input from the control unit Is controlled to modulate incident light.
The liquid crystal panels 322R, 322G, and 322B have a resolution much higher than that of the liquid crystal panels 312R, 312G, and 312B of the sub spatial light modulator 310 (for example, the number of pixels is about 1,300 × 800). In addition, the gradation of each color is configured to allow, for example, 256 gradations. Note that the number of gradations of each color in the liquid crystal panels 312R, 312G, and 312B of the sub spatial light modulator 310 may be equal to or different from the number of gradations of the liquid crystal panels 322R, 322G, and 322B. Is possible.

  The incident side polarizing plates 321R and 321B are disposed so as to transmit p-polarized light, and the incident side polarizing plate 321G is disposed so as to transmit s-polarized light. The exit-side polarizing plates 323R and 323B transmit the s-polarized light, and the exit-side polarizing plate 323G is disposed to transmit the p-polarized light. That is, in each spatial light modulator 320, the incident side polarizing plates 321R, 321G, and 321B and the emission side polarizing plates 323R, 323G, and 323B are configured in a crossed Nicols arrangement.

The spatial light modulator 320 modulates the color light whose light amount has been adjusted by the sub spatial light modulator 310 according to the image information, and forms an image for each color light in the pixel region.
Specifically, the first spatial light modulator 320R modulates the p-polarized R light emitted from the first sub-spatial light modulator 310R and emits it as s-polarized R light. Similarly, the third spatial light modulator 320B modulates p-polarized B light emitted from the third sub-spatial light modulator 310B and emits it as s-polarized B light. Then, the second spatial light modulator 320G modulates the s-polarized G light emitted from the second sub-spatial light modulator 310G and emits it as p-polarized G light.

  As described above, the electro-optical device 300 adjusts the amount of light of each incident color light by the sub spatial light modulator 310, forms an image of each color light by the spatial light modulator 320, and s as the first polarized light. R light (first color light) and B light (third color light) of polarized light are emitted, and G light (second color light) of p-polarized light as second polarized light is emitted.

[Configuration of cross dichroic prism]
As shown in FIG. 2, the cross dichroic prism 400 includes a first reflective film formed of a dielectric multilayer film on a substantially X-shaped interface in a top view obtained by bonding four right-angle prisms as described above. 401 and a second reflective film 402 are provided.
The first reflection film 401 is a dielectric multilayer film that reflects R light and transmits G light and B light, and the second reflection film 402 is a dielectric that reflects B light and transmits R light and G light. It is a multilayer film.

Here, the reflection characteristics of the first reflective film 401 and the second reflective film 402 of the cross dichroic prism 400 will be described.
FIG. 5 is a graph showing the spectral reflectance characteristics of the first reflective film 401 and the second reflective film 402, and FIG. 5A shows the spectral reflectance of the first reflective film 401 for s-polarized light and p-polarized light. FIG. 5B is a graph showing an example of the characteristics, and FIG. 5B is a graph showing an example of the spectral reflectance characteristics of the second reflective film 402 with respect to s-polarized light and p-polarized light. In FIG. 5, the reflectance characteristic for s-polarized light is indicated by a broken line, and the reflectance characteristic for p-polarized light is indicated by a solid line. Here, in the present embodiment, the s-polarized light that is the first polarized light having the first polarization direction includes a normal to the light incident plane of the first reflective film 401 and the central axis of the light beam incident thereon. This is polarized light having an electric field component in a direction perpendicular to the incident surface. Further, in the present embodiment, the p-polarized light that is the second polarized light having the second polarization direction is an incident surface that includes a normal to the light incident plane of the first reflective film 401 and the central axis of the light beam incident thereon. Polarized light having an electric field component in a direction parallel to the light. In the present embodiment, the incident surface including the normal of the light incident plane of the first reflective film 401 and the central axis of the light beam incident thereon is incident on the normal of the light incident plane of the second reflective film 402 and the normal axis. It is comprised so that it may be parallel with respect to the entrance plane containing the central axis of a light beam.

Usually, the wavelength region of R light is set to about 580 nm to about 700 nm, the wavelength region of G light is set to about 500 nm to about 580 nm, and the wavelength region of B light is set to about 400 nm to about 500 nm. .
As shown in FIG. 5A, the first reflective film 401 reflects in the region of about 530 nm to about 750 nm for s-polarized light, and about 600 nm to about 700 nm for p-polarized light. It has the property of reflecting in the area. That is, the first reflective film 401 reflects a wavelength in a region wider than the wavelength region of R light for s-polarized light, and reflects a wavelength in a region narrower than the wavelength region of R light for p-polarized light. It has characteristics. That is, the first reflective film 401 reflects s-polarized light with less loss and more efficiently than p-polarized light with respect to R light.
The first reflective film 401 reflects a part of the G light wavelength region in the s-polarized light with respect to the G light, but reflects the light in the G light wavelength region in the p-polarized light. Since it hardly reflects, p-polarized light is transmitted efficiently with less loss than s-polarized light.

As shown in FIG. 5B, the second reflective film 402 reflects in the region of about 390 nm to about 530 nm for s-polarized light and about 400 nm to about 460 nm for p-polarized light. It has the property of reflecting in the area. That is, the second reflective film 402 reflects a wavelength in a region wider than the wavelength region of B light for s-polarized light, and reflects a wavelength in a region narrower than the wavelength region of B light for p-polarized light. It has characteristics. That is, the second reflective film 402 reflects s-polarized light more efficiently with less loss than p-polarized light with respect to B light.
The second reflective film 402 reflects part of the G light wavelength region in the s-polarized light with respect to the G light, but reflects the light in the G light wavelength region in the p-polarized light. Since it hardly reflects, p-polarized light is transmitted efficiently with less loss than s-polarized light.

The three color lights emitted from the electro-optical device 300 are R light reflected by the first reflective film 401, B light reflected by the second reflective film 402, and the first reflective film 401 and the second reflective film. The G light transmitted through 402 is combined in the traveling direction of the G light.
Specifically, the R light of the s-polarized light emitted from the first spatial light modulator 320R is transmitted through the second reflective film 402 and reflected by the first reflective film 401, and from the third spatial light modulator 320B. The emitted B light of s-polarized light is transmitted through the first reflective film 401 and reflected by the second reflective film 402, and the G light of p-polarized light emitted from the second spatial light modulator 320G is the first light. The three color lights are combined through the reflection film 401 and the second reflection film 402.

  As described above, R light (first color light) and B light (third color light) of s-polarized light as the first polarized light are incident on the cross dichroic prism 400, and p-polarized light as the second polarized light. Light G light (second color light) enters. That is, in the cross dichroic prism 400, the color light desired to be reflected by either the first reflective film 401 or the second reflective film 402 has a polarization direction in which the reflection efficiency of the first reflective film 401 and the second reflective film 402 is high. Colored light that is incident as polarized light and is transmitted through both the first reflective film 401 and the second reflective film 402 is incident as polarized light in a polarization direction with high transmission efficiency of the first reflective film 401 and the second reflective film 402. The cross dichroic prism 400 synthesizes the three color lights by increasing the utilization efficiency of the incident color lights. The light combined with the cross dichroic prism 400 is projected onto a projection surface such as a screen by the projection lens 500.

As described above, according to the present embodiment, the following effects can be obtained.
(1) Since the sub spatial light modulation device 310 is disposed on the light incident side of the spatial light modulation device 320, the amount of color light emitted from the illumination device 10 is adjusted, and the contrast ratio of the projected image is adjusted. It is possible to improve, that is, to expand the brightness range (dynamic range) of the image that can be displayed.
In addition, the cross dichroic prism 400 receives color light in the polarization direction with high reflection efficiency of the first reflective film 401 and the second reflective film 402, and the cross dichroic prism 400 increases the use efficiency of the incident color light to increase the three colors. Synthesize the colored light.
Therefore, the projector 1000 can project an image with an improved contrast ratio and brightness, and can realize an image projection with high image quality and excellent compatibility with the use environment.

  (2) Since the sub spatial light modulator 310 is provided corresponding to each of the three color lights, the light quantity of the three color lights emitted from the illumination device 10 is adjusted, and the projector 1000 further increases the contrast ratio. The projected image can be projected.

(3) The illumination device 10 emits light aligned with the s-polarized light, and the first sub spatial light modulator 310R and the third sub spatial light modulator 310B emit light with the incident side polarizing plates 311R and 311B. The side polarizing plates 313R and 313B are configured in a crossed Nicols arrangement, and in the second sub spatial light modulator 310G, the incident side polarizing plates 311G and the exiting side polarizing plates 313G are configured in a parallel Nicols arrangement.
Thus, since the direction of the transmission axis of the polarizing plate is different between the first sub spatial light modulation device 310R and the third sub spatial light modulation device 310B, and the second sub spatial light modulation device 310G, the illumination device The three color lights, which are s-polarized light beams emitted from 10, can be converted into a desired polarization direction and incident on the cross dichroic prism 400. That is, the R light (first color light) and B light (third color light) emitted from the illumination device 10 enter the cross dichroic prism 400 as s-polarized light (first polarized light), and G light (second light). Can be easily configured so as to be incident on the cross dichroic prism 400 as p-polarized light (second polarized light).

(Second Embodiment)
Hereinafter, a projector according to a second embodiment will be described with reference to the drawings. In the following description, the same components and the same members as those of the projector 1000 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.
The illumination device (not shown) in the projector according to the present embodiment is configured such that the illumination device 10 according to the first embodiment emits color light of s-polarized light, whereas the illumination device 10 emits color light of p-polarized light. In addition, the projector according to the present embodiment includes an electro-optical device 600 that is different from the electro-optical device 300 according to the first embodiment.

FIG. 6 is a schematic diagram showing the electro-optical device 600 and the cross dichroic prism 400 of the present embodiment.
As shown in FIG. 6, the electro-optical device 600 includes a sub spatial light modulation device 610 different from the sub spatial light modulation device 310 in the first embodiment, and a spatial light modulation common to the spatial light modulation device 320 in the first embodiment. A device 320 is provided.

  The sub spatial light modulation device 610 includes a first sub spatial light modulation device 610R for R light, a second sub spatial light modulation device 610G for G light, and a third sub spatial light modulation device 610B for B light. I have. Each sub spatial light modulator 610 includes a TN type liquid crystal panel 612, an incident side polarizing plate 611, and an emission side polarizing plate 613 disposed on the light incident side and the light emitting side of the liquid crystal panel 612, respectively.

In the first sub spatial light modulator 610R and the third sub spatial light modulator 610B, the incident side polarizing plate 611 and the exit side polarizing plate 613 are arranged in parallel Nicols, and the incident side polarizing plate 611 and the exit side polarized light are arranged. The plate 613 is arranged to transmit p-polarized light.
In the second sub-spatial light modulation device 610G, the incident-side polarizing plate 611 and the exit-side polarizing plate 613 are arranged in a crossed Nicols arrangement, and the incident-side polarizing plate 611 transmits p-polarized light, and this exit-side polarizing plate 613 is arranged to transmit s-polarized light.
As described above, the incident side polarization plate 611 and the emission side polarization plate 613 in the first sub spatial light modulation device 610R and the third sub spatial light modulation device 610B are configured in a parallel Nicol arrangement. The incident side polarization plate 611 and the emission side polarization plate 613 in the second sub spatial light modulation device 610G are configured in a crossed Nicols arrangement.

  In the first sub spatial light modulator 610R and the third sub spatial light modulator 610B, the higher the voltage applied to the liquid crystal panel 612, the more incident color light is transmitted, and the second sub spatial light is transmitted. In the modulation device 610G, as the voltage applied to the liquid crystal panel 612 is lower, more incident color light is transmitted and the amount of transmitted color light is adjusted.

  The color light emitted from the sub spatial light modulator 610 is modulated by the spatial light modulator 320. Then, similarly to the electro-optical device 300 of the first embodiment, the electro-optical device 600 has the s-polarized light R light (first color light), the B light (third color light), and the p-polarized light G light. (Second color light) is emitted.

  Similarly to the first embodiment, R light (first color light) and B light (third color light) of s-polarized light as the first polarized light are incident on the cross dichroic prism 400 and the second polarized light is input. P-polarized G light (second color light) is incident. As in the first embodiment, the light synthesized by the cross dichroic prism 400 is projected onto a projection surface such as a screen by the projection lens 500.

As described above, the projector according to the present embodiment adjusts the amount of light of the p-polarized light emitted from the illumination device 10 with the sub spatial light modulator 610 and modulates it with the spatial light modulator 320, and then s-polarized light. R light (first color light), B light (third color light), and G light (second color light) of p-polarized light are emitted. Then, like the cross dichroic prism 400 of the first embodiment, the cross dichroic prism 400 efficiently synthesizes the incident three color lights and emits them to the projection lens 500. The projection lens 500 outputs the synthesized light. Project.
As described above, according to the projector of this embodiment, even when the illumination device 10 is configured to emit p-polarized light, the same effect as the projector 1000 of the first embodiment can be obtained. Can do.

(Third embodiment)
Hereinafter, a projector according to a third embodiment will be described with reference to the drawings. In the following description, the same components and the same members as those of the projector 1000 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.

The projector according to the present embodiment includes an electro-optical device 700 having a retardation plate 710.
FIG. 7 is a schematic diagram showing the electro-optical device 700 and the cross dichroic prism 400 of the present embodiment.
As shown in FIG. 7, the electro-optical device 700 includes a phase difference plate 710 disposed on the optical path of the G light, and is different from the second sub spatial light modulation device 310G in the first embodiment. A spatial light modulator 720G is provided.

The phase difference plate 710 has a function of converting either s-polarized light or p-polarized light into the other, and is disposed on the light incident side of the second sub spatial light modulator 720G.
The phase difference plate 710 converts the G light emitted from the illumination device 10 from s-polarized light to p-polarized light.
The second sub spatial light modulator 720G includes an incident side polarizing plate 721, a liquid crystal panel 722, and an emission side polarizing plate 723. The second sub spatial light modulator 720G is configured in a crossed Nicols configuration so that the incident-side polarizing plate 721 transmits p-polarized light and the exit-side polarizing plate 723 transmits s-polarized light. Then, the second sub spatial light modulation device 720G adjusts the amount of p-polarized light emitted from the phase difference plate 710 that is transmitted through the G light.

The first sub spatial light modulation device 310R and the third sub spatial light modulation device 310B are also configured so that the polarizing plates are in a crossed Nicols arrangement, and the three sub spatial light modulation devices 310 of the present embodiment include: As the voltage applied to the liquid crystal panels 312R and 312B (see FIG. 2) and the liquid crystal panel 722 is lower, more incident color light is transmitted. A retardation plate 710 is disposed between the second sub spatial light modulation device 310G and the second spatial light modulation device 320G, or between the second spatial light modulation device 320G and the cross dichroic prism 400. May be.
As described above, according to the projector of this embodiment, the following effects can be obtained in addition to the projector 1000 of the first embodiment.
The three sub spatial light modulators 310 adjust the amount of light so as to transmit more incident color light as the voltage applied to the liquid crystal panels 312R, 312B, and 722 is lower. Therefore, the three sub spatial light modulators 310 are applied to the liquid crystal panels 312R, 312B, and 722. The voltage control method can be simplified.

(Modification)
In addition, you may change the said embodiment as follows.
In the embodiment, three sub spatial light modulators 310 are provided corresponding to the three color lights, but any one of them may be provided. For example, the first sub spatial light modulators 310R, 610R, and 710R and the third sub spatial light modulators 310B, 610B, and 710B in the electro-optical devices 300 and 600 (see FIG. 6) and 700 may be omitted. . Since the second sub spatial light modulators 310G, 610G, and 710G can adjust G light having a higher specific visibility characteristic than other color lights, the second sub spatial light modulators 310G, 610G, and 710G are not provided. In comparison, the contrast ratio of the projected image can be increased.

The cross dichroic prism 400 receives R light (first color light) and B light (third color light) as s-polarized light as the first polarized light, and G light (p-polarized light as the second polarized light ( If the second color light) is configured to be incident, the liquid crystal panels of the sub spatial light modulator 310 and the spatial light modulator 320 may be configured not only as a TN type but also as a VA (Vertical Alignment) type, A TN liquid crystal panel and a VA liquid crystal panel may be mixed.
Further, R light (first color light) and B light (third color light) of s-polarized light as the first polarized light are incident on the cross dichroic prism 400, and G of p-polarized light as the second polarized light is input. If the light (second color light) is configured to be incident, a compensation element that compensates for a phase shift of light such as a WV (Wide View) film may be arranged in the electro-optical device. Good.

  In the embodiment, the sub spatial light modulation device 310 is arranged on the light incident side of the spatial light modulation device 320, but the cross dichroic prism 400 has the s-polarized R light (first light) as the first polarized light. Color light) and B light (third color light) are incident, and G light (second color light) of p-polarized light as the second polarized light is incident, the spatial light modulator 320. It may be arranged on the light exit side.

  In the embodiment, the s-polarized light is the first polarized light, and the p-polarized light is the second polarized light. However, the first reflective film 401 and the second reflective film 402 in the cross dichroic prism 400 are different from the p-polarized light. When formed of a member having a characteristic having a higher reflectance in a wider wavelength region than that for s-polarized light, the p-polarized light is set as the first polarized light, and the s-polarized light is set as the second polarized light. Then, the projector causes the first colored light of the first polarized light that is p-polarized light, the third colored light, and the second colored light of the second polarized light that is s-polarized light to enter the cross dichroic prism 400. Configured.

The retardation plate 710 in the third embodiment is provided in the optical path of G light, but may be provided in the optical path of other color light.
For example, although not shown, the light incident side of the first sub-spatial light modulation device 610R on the optical path of R light and the third sub-space on the optical path of B light in the electro-optical device 600 of the second embodiment. It is also possible to arrange the phase difference plate 710 on the light incident side of the light modulation device 610B. In this case, in the first sub spatial light modulator 610R and the third sub spatial light modulator 610B, the incident side polarizing plate 611 transmits s-polarized light and the exit side polarizing plate 613 transmits p-polarized light. Configured in Nicol arrangement. According to this configuration, the three sub spatial light modulators 310 adjust the amount of light so as to transmit more incident color light as the voltage applied to the liquid crystal panels 312R, 312B, and 722 is lower. , 312B, 722, the control method of the voltage applied to 722 can be simplified.
Further, among the three color lights, there may be provided an optical path of colored light in which the sub spatial light modulator 310 is not disposed, and the phase difference plate 710 may be disposed in this optical path.

A relay lens 810 may be disposed between the sub spatial light modulators 310, 610, and 710 and the spatial light modulator 320.
FIG. 8 is a schematic diagram showing an electro-optical device 800 and a cross dichroic prism 400 according to this modification.
As shown in FIG. 8, the relay lens 810 is disposed between the sub spatial light modulator 310 and the spatial light modulator 320 for each color light. In the embodiment, the optical components are arranged so that the partial light beams divided by the first lens array 120 overlap the spatial light modulator 320. In this modification, the first lens array is arranged. The position of the optical component is set so that the plurality of partial light beams divided by 120 overlap the sub spatial light modulator 310. The relay lens 810 is arranged so that a plurality of partial light beams that have passed through the sub spatial light modulator 310 overlap the spatial light modulator 320. As a result, the contrast ratio of the projected image can be further improved.

The spatial light modulation device 320 and the sub spatial light modulation device 310 of the embodiment are configured using a transmissive liquid crystal panel, but may be a reflective liquid crystal panel. Further, the incident-side polarizing plate and the exit-side polarizing plate used in the sub spatial light modulation device and the spatial light modulation device may use a reflective polarizing plate.
The above embodiment relates to a configuration in which white light is divided into three wavelength regions of R, G, and B by the color separation optical system 200 and modulated. The present invention is not limited to such a configuration, and the present invention can also be applied to a configuration in which white light is divided into two wavelength regions and modulated. This is because even in such a configuration, a multicolor image can be displayed. In such a configuration, the color light that is to be reflected by the dielectric multilayer film of the color synthesis optical device is incident on the color synthesis optical device as s-polarized light, and the color light that is to be transmitted through the dielectric multilayer film is p. What is necessary is just to adapt the structure demonstrated in the said embodiment so that it may inject into a color synthetic | combination optical apparatus with polarized light.
In the projector according to the embodiment, the first color light is described as red light, the second color light as green light, and the third color light as blue light. However, the present invention is not limited to this, and the first color light, The second color light and the third color light may be different colors belonging to the respective wavelength ranges.
In the projector according to the embodiment, the number of pixels of the liquid crystal panels 312 and 612 of the sub spatial light modulators 310 and 610 is less than the number of pixels of the liquid crystal panel 322 of the spatial light modulator 320. However, the number of pixels of the liquid crystal panels 312 and 612 of the sub spatial light modulators 310 and 610 can be the same as or larger than the number of pixels of the liquid crystal panel 322 of the spatial light modulator 320.

The light source 110 is not limited to one using a discharge type lamp, and may be a solid-state light source such as a lamp of another type or a light emitting diode.
In addition, a plurality of light sources that emit different color lights may be used, and the illumination device may be configured so as to simplify the color separation optical system or not include the color separation optical system. For example, the illumination device may be configured to include a plurality of LEDs (Light Emitting Diodes) that emit three colored lights and elements that align the polarization direction of the light emitted from each LED.

  DESCRIPTION OF SYMBOLS 10 ... Illuminating device, 100 ... Integrator illumination system, 110 ... Light source, 310,610 ... Sub spatial light modulator, 310B, 610B ... Third sub spatial light modulator, 310G, 610G, 720G ... Second sub spatial light Modulator, 310R, 610R ... first sub spatial light modulator, 311B, 311G, 311R, 611, 721 ... incident side polarizing plate, 312B, 312G, 312R, 612, 722 ... liquid crystal panel, 313B, 313G, 313R, 613, 723... Exit side polarizing plate, 320... Spatial light modulation device, 320B... Third spatial light modulation device, 320G... Second spatial light modulation device, 320R ... first spatial light modulation device, 321B, 321G, 321R: Incident side polarizing plate, 322B, 322G, 322R ... Liquid crystal panel, 323B, 323G, 323R ... Emission side polarizing plate, 00 ... cross dichroic prism 401 ... first reflecting film, 402 ... second reflecting film, 500 ... projection lens 710 ... retardation plate 810 ... relay lens, 1000 ... projector.

Claims (6)

An illuminating device having a light source and emitting a first color light and a second color light belonging to each wavelength region with a polarization direction aligned in a predetermined direction;
A first spatial light modulator for modulating the first color light;
A second spatial light modulator for modulating the second color light;
The secondary spatial light modulator is disposed on at least one of the first spatial light modulation device and the second spatial light modulation device and arranged to adjust the amount of light emitted by modulating incident color light. A spatial light modulator;
A first reflective film that reflects the first color light emitted from the first spatial light modulator and transmits the second color light emitted from the second spatial light modulator; A color synthesizing optical device that synthesizes each color light modulated by the first spatial light modulation device and the second spatial light modulation device;
A projection optical device for projecting light synthesized by the color synthesis optical device;
With
The first color light incident on the color synthesis optical device is first polarized light having a first polarization direction;
The projector according to claim 1, wherein the second color light incident on the color synthesizing optical device is second polarized light having a second polarization direction orthogonal to the first polarization direction. The projector according to claim 1,
The sub spatial light modulator is
A first sub-spatial light modulator that adjusts the amount of light emitted by modulating the first color light;
A second sub spatial light modulator that adjusts the amount of light emitted by modulating the second color light;
A projector comprising: The projector according to claim 2,
The first sub spatial light modulator and the second sub spatial light modulator are
A liquid crystal panel that modulates the incident light;
An incident-side polarizing plate disposed on the light incident side of the liquid crystal panel;
An exit-side polarizing plate disposed on the light exit side of the liquid crystal panel;
Each with
The incident side polarizing plate and the emission side polarizing plate in the first sub spatial light modulation device are arranged to be either one of a parallel Nicol arrangement and a crossed Nicol arrangement,
The projector according to claim 2, wherein the incident-side polarizing plate and the emission-side polarizing plate in the second sub-spatial light modulation device are arranged to be the other of the parallel Nicol arrangement and the crossed Nicol arrangement. It is a projector as described in any one of Claims 1-3, Comprising:
A retardation plate for converting any one of the incident first polarized light and the second polarized light into the other;
The projector, wherein the retardation plate is disposed between the illumination device and the color synthesis optical device on an optical path of at least one of the first color light and the second color light. The projector according to claim 2,
A retardation plate for converting any one of the incident first polarized light and the second polarized light into the other;
The retardation plate is disposed between the illumination device and the color synthesizing optical device on the optical path of one of the first color light and the second color light,
The first spatial light modulation device, the second spatial light modulation device, the first sub spatial light modulation device, and the second sub spatial light modulation device are:
A liquid crystal panel that modulates the incident light;
An incident-side polarizing plate disposed on the light incident side of the liquid crystal panel;
An exit-side polarizing plate disposed on the light exit side of the liquid crystal panel;
Each with
The incident-side polarizing plate and the emission in each of the first spatial light modulation device, the second spatial light modulation device, the first sub spatial light modulation device, and the second sub spatial light modulation device The side polarizing plate is a projector that is arranged so as to have either a parallel Nicols arrangement or a crossed Nicols arrangement. It is a projector as described in any one of Claims 1-5, Comprising:
The projector according to claim 1, wherein the first polarized light is s-polarized light, and the second polarized light is p-polarized light.

Images