JPH1114942A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector capable of making high contrast performance compatible with high output performance with a simple constitution. SOLUTION: Images of respective components of R, G, B are written into an SLM 1 by a CRT 37 with an FOP 36. Besides, the light emitted from a white light source 31 is adjusted in a collimating lens 32, a UV filter 33 and an IR filter 34 and the corresponding chromatic light of R, G, B is taken out from it by the control of the wavelength variable filter 35. This light passes through a PBS(polarizing bean splitter) 2 to be modulated is the SLM 1 and an image component included in this light is taken out in the PBS 2 and a polarizing plane 3 to pass through a projection lens 39 to be projected on a screen 40. Here, since only an S-polarized light is taken out in the polarizing plate 3 by making the transmissivity of the S-polarized light lower than that of a P-polarized light of the PBS 2, the S-polarized light of non-modulation to be included in the projection light is reduced to enhance the contract.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projector using a reflection type spatial light modulator.

[0002]

2. Description of the Related Art In a projector using a reflection type spatial light modulator, a polarizing beam splitter (PBS) is widely used as a device that performs both functions of a polarizer and an analyzer. As shown in FIG. 11, a typical prism type PBS 2 has a dielectric multilayer mirror 21 formed on a slope of a triangular prism 22 and then glues this slope to the slope of another triangle prism 23 to form a rectangular parallelepiped or the like. It was formed in the shape of. The light incident from any of the four surfaces of the PBS 2 facing the mirror 21 reaches the mirror, and then the P-polarized light component passes through the mirror 21 and travels straight to the PB.
The S-polarized light component is output from the surface facing the light incident surface of S2, while the S-polarized component is reflected by the mirror 21 and output from the surface adjacent to the light incident surface of the PBS 2 without passing through the mirror 21. In this way, the PS polarization component can be separated.

However, a metal halide lamp or a xenon lamp, which is a high-output white light source used as a light source of a projector, has an arc length and is not a perfect point light source. It is possible. Therefore, the light incident on the PBS from such a light source has a predetermined spread angle. It is difficult to produce a PBS having a good extinction ratio (a ratio of each transmittance of P-polarized light and each reflectance of S-polarized light) to incident light having such a spread angle. It cannot be completely separated. In particular, the arc length increases as the output power of the light source increases, and the divergence angle of the light incident on the PBS increases. Therefore, it has been difficult to achieve high contrast characteristics with a high-output projector.

Further, in the case of a single-panel type color projector, one PBS has to cope with all the light in the visible light (400 to 700 nm) region. It has been difficult to manufacture a dielectric multilayer mirror having a good extinction ratio in the wavelength region, that is, a PBS.

As a technique for improving the contrast characteristic of a projector using such a PBS, Japanese Patent Laid-Open No.
There is a technique disclosed in Japanese Patent Application Laid-Open No. 100247. This corresponds to the PB of the projector, as shown in FIG.
By providing polarizing plates 3i and 3o for extracting only a specific linearly polarized light component on both the input and output sides of S2, the extinction ratio is improved and the contrast characteristics of the projector are improved.

[0006]

However, a polarizer, in which iodine is impregnated into an orientated polymer, which is currently most widely used, so that the polymer exhibits dichroism, has a very high transmittance. In addition, light in the polarization direction desired to be extracted is partially absorbed. For this reason, when a plurality of polarizing plates are used, the light amount loss due to the absorption increases, and the intensity of the output light of the projector, that is, the brightness decreases. In order to prevent this decrease in brightness, it is necessary to increase the output intensity of the light source. However, when the intensity of the light source is increased, the amount of light absorbed by the polarizing plate particularly arranged on the light source side is increased, and thus the light amount is absorbed. Since light is converted to heat, the temperature of the polarizing plate increases.
Since this kind of polarizing plate is weak to heat, its characteristics are degraded by a rise in temperature. Therefore, there is a limit in increasing the output intensity of the light source, and it has been difficult to create a high-output and high-contrast projector.

An object of the present invention is to provide a projector which has both a high contrast and a high output with a simple configuration.

[0008]

SUMMARY OF THE INVENTION A projector according to the present invention comprises: a reflective spatial light modulator that modulates read light incident from one surface and generates output light from an incident surface of the read light; It is arranged on the readout light incident surface side of the modulator, transmits the P-polarized light component of the incident light and reflects the S-polarized light component in a direction substantially perpendicular to the incident direction, so that the incident readout light goes straight and is incident. A polarizing beam splitter that separates output light in a direction substantially perpendicular to the readout light and emits the light, and a polarizing plate that extracts an S-polarized component disposed on the optical path of the output light separated by the polarizing beam splitter, This polarization beam splitter is S
The transmittance of the polarization component is lower than the reflectance of the P polarization component.

According to this, of the readout light incident on the PBS, light mainly including the P-polarized light component is guided to the spatial light modulator. Since the transmittance of the S-polarized light component is suppressed, the ratio of the P-polarized light component increases. Since the spatial light modulator modulates the reading light according to the written image, the image information is included in the S-polarized component of the output light. This output light is again
The s-polarized light component containing image information upon entering the BS is output in a direction orthogonal to the readout light. Although this output light contains P-polarized light components to some extent, since the P-polarized light components are removed by the polarizing plate placed on the optical path of the output light, only the S-polarized light components containing image information are output.

[0010] Alternatively, a reflective spatial light modulator for emitting output light generated by modulating readout light incident from one surface from the incident surface of the readout light, and a reflective spatial light modulator disposed on the readout light incident surface side of the optical modulator. Then, by transmitting the P-polarized light component of the incident light and reflecting the S-polarized light component in a direction substantially perpendicular to the incident direction, the input read light is reflected in a direction substantially perpendicular to the incident direction and the output light incident. A polarizing beam splitter that transmits through and separates out the readout light, and a polarizing plate that extracts a P-polarized component disposed on the optical path of the output light separated by the polarizing beam splitter, and the polarizing beam splitter includes: The reflectance of the P polarization component may be lower than the transmittance of the S polarization component.

[0011] According to this, of the readout light incident on the PBS, light mainly including the S-polarized light component is reflected and guided to the spatial light modulator. In the PBS, since the reflectance of the P-polarized light component is suppressed, the ratio of the S-polarized light component increases. Since the spatial light modulator modulates the read light according to the written image, the image information is included in the P-polarized light component of the output light. This output light enters the PBS again, and the P-polarized light component including the image information goes straight and is output in a direction orthogonal to the readout light. This output light contains an S-polarized component to some extent, but since the S-polarized component is removed by a polarizing plate placed on the optical path of the output light, only the P-polarized component containing image information is output.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description will be omitted.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 is a diagram illustrating a configuration of a single-panel CRT-SLM color projector according to an embodiment of the present invention. FIG. 2 is a diagram showing the position setting of the PBS 2 of the projector.

The projector of the present embodiment is a so-called single-panel type color projector for writing an image on a CRT.

On the write light incident surface side of the SLM 1, FO
An image writing CRT 37 is connected via P36. This CRT 37 has a video rate of 3
It is driven at 180 Hz twice. On the other hand, the PBS 2 is disposed on the read light incident surface side of the SLM 1 so as to face the SLM 1. This PBS 2 has the structure shown in FIG. 2 and has a structure in which a multilayer mirror 21 is sandwiched between triangular prisms 22 and 23. And PBS2 is S
The output light returning from LM1 is arranged to be incident on the multilayer mirror at an incident angle of 55 degrees. In the PBS 2, the transmittance of S-polarized light of the multilayer mirror 21 in the PBS is set lower than the reflectance of P-polarized light, as described later in detail.

Then, as shown in FIG.
An optical system for reading light is arranged at a position opposite to the SLM 1 with the image data interposed therebetween. The optical system of the readout light includes a white light source 31 formed of a metal halide lamp, a collimator lens 32 for adjusting the readout light to parallel light, a UV filter 33 for removing a wavelength component in an ultraviolet region and an infrared region, respectively.
An R filter 34 and a wavelength tunable filter 35 that switches each of the monochromatic light components of RGB to be transmitted at a cycle of 180 Hz. Here, the wavelength region of the read light incident on the wavelength tunable filter 35 is a visible light region of 400 to 700 nm, and the spread angle of the read light incident on the PBS 2 is about ± 5 degrees. Both the wavelength tunable filter 35 and the image writing CRT 37 are connected to a controller 38 for control.

A polarizing plate 3 for extracting the S-polarized component of the incident light, a projection lens 39 for enlarging the projection area of the incident light, and a screen 40 for projecting an image are provided on the reflected light path of the PBS 2.
Is arranged.

Here, the PBS 2 used in the present embodiment will be described in detail.

Table 1 shows the configuration of the multilayer mirror 21 of the PBS 2 of the present embodiment. This multilayer mirror 21
Is obtained by alternately stacking 21 layers of TiO ₂ and SiO ₂ .

[0020]

[Table 1]

3 and 4, a PBS using a conventional multilayer mirror and a PB using a multilayer mirror according to the present embodiment will be described.
The optical characteristics of S will be described in comparison. FIG. 3 shows a conventional PB
FIG. 4 is a diagram illustrating the spectral optical characteristics of S, and FIG. 4 is a diagram illustrating the spectral optical characteristics of the PBS of the present embodiment.

Referring to the light of 400 to 700 nm, which is a visible light region, in the conventional product, as shown in FIG. 3A, the reflectance of S-polarized light is 45 degrees at an incident angle of 45 degrees. About 95%, and 93 to 9 for light shifted by ± 5 degrees.
The reflectance is about 6%. Therefore, each transmittance is about 4 to 7%. The reflectance of the P-polarized light at this time is 1% or less when the incident angle is 45 degrees, and the reflectance when the light shifted by ± 5 degrees is 7% as shown in FIG. It is about. Therefore, when white light having a spread angle of 5 degrees is incident on the conventional PBS at a central incident angle of 45 degrees, the extinction ratio is 20: 1 for both transmission and reflection.

On the other hand, in the PBS of this embodiment, FIG.
As shown in FIG.
The degree of reflection is 99% and the transmittance is about 1%, and for light shifted by ± 5 degrees, the reflectance is 98% and the transmittance is about 2%. On the other hand, as shown in FIG. 4B, the reflectance of P-polarized light is 1% at an incident angle of 55 degrees, and about 8 to 10% for light shifted by ± 5 degrees. Therefore, the extinction ratio when white light having a spread angle of 5 degrees is made incident on the PBS of this embodiment at a central incident angle of 55 degrees is 100: 1 for transmission and 100% for transmission.
The reflection is 10: 1, and although the reflection characteristics are degraded, the transmission characteristics are improved.

Next, the operation of this embodiment will be described with reference to FIGS.

The white light emitted from the white light source 1 is adjusted by the collimator lens 32, the UV filter 33, and the IR filter 34 into light in a substantially parallel visible light region, and is incident on the wavelength variable filter 35. Tunable filter 35
With the control of the controller 38, only a predetermined monochromatic light of RGB is transmitted every 1/180 second and the PB
It is incident on S2. The read light incident on PBS2 is PS
Each polarization component is included at the same rate. Here, the light amount of each polarized light component of the readout light is represented by (light amount of a P-polarized light component, light amount of an S-polarized light component), and hereinafter, the light amount of the polarized light component included in the light is represented by a similar format. Then, the light amount of the reading light can be expressed as (1.0, 1.0).

The light incident on the PBS 2 is reflected by the multilayer mirror 21.
Are partly reflected by the light emitting device and are emitted from the surface of the PBS 2 facing the screen and removed. The remaining light passes through PBS2 and goes to SLM1. As described above, the extinction ratio of the multilayer mirror in this embodiment is 100: 1 for transmission,
Because of the 10: 1 reflection, most of the P-polarized light is transmitted while most of the S-polarized light is reflected. As a result, SLM1
Can be represented by (0.901, 0.009).

On the other hand, the SLM 1 has a controller 38.
The image corresponding to the light component of the read light is written via the FOP 36 by the CRT 37 controlled as described above.
The wavelength component of the reading light changes according to the written image. When 100% modulation is performed, the P-polarized light and the S-polarized light are reversed, so that the amount of output light is (0.009,
0.901). On the other hand, in the case of 0% modulation, the read light is output as it is, so that the amount of output light is
(0.901, 0.009).

The output light thus modulated is again transmitted to the PBS
2 is incident. Most of the incident light is transmitted by the P-polarized light component, and the S-polarized light component is reflected by the mirror 21. Therefore, the amount of reflected output light is (0.0009, 0.893) when the modulation is 100%, and (0.0893, 0.00893) when the modulation is 0%. The reflected output light is incident on the polarizing plate 3. Since only the light of the S-polarized component is extracted from the polarizing plate 3, the contrast ratio of the output light is equal to the light amount ratio of the S-polarized component at the time of 100% modulation and at the time of 0% modulation, and is 100: 1. Here, when the conventional PBS is used, the extinction ratio at the time of transmission is low, so that the S-polarized light component included in the readout light increases. Therefore, S included in the output light at the time of 0% modulation
Since the polarization component increases, the final contrast ratio is 2
Only 0: 1. Therefore, according to the present embodiment,
This has the effect of improving the contrast ratio. Furthermore, one polarizing plate
Since only one sheet is used, the absorption of the S-polarized light component including image information is suppressed as compared with the case where a plurality of sheets are used, so that the output light intensity itself can be increased.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a configuration diagram of a projector according to the second embodiment. The basic configuration is the same as that of the projector shown in FIG.
The difference is that the light enters the M1 and the output light passes through the PBS 2a and is projected on the screen 40 via the polarizing plate 3a. The polarizing plate 3a removes the S-polarized light component from the incident light and extracts the P-polarized light component.

Here, as shown in FIG. 6, the PBS 2a is arranged such that the readout light is incident on the multilayer mirror 21a at an incident angle of 55 degrees and the reflected light is incident on the SLM1. This PBS 2a sets the reflectance of P-polarized light to S
It is set lower than the transmittance of polarized light. Table 2 shows the configuration of the multilayer mirror 21a of the PBS 2a.
This multilayer mirror 21a is formed by alternately stacking nine layers of TiO ₂ and SiO ₂ .

[0031]

[Table 2]

FIG. 7 shows the spectral optical characteristics of the multilayer mirror 21a. Referring to the light in the visible light region of 400 to 700 nm, as shown in FIG. 3A, the reflectance is 90% for the S-polarized light at an incident angle of 55 ° ± 5 °.
And the transmittance is about 10%. On the other hand, for P-polarized light, as shown in FIG. 4B, at an incident angle of 55 degrees, the reflectance is almost 0%, and at an incident angle shifted by ± 5 degrees,
The reflectance is about 2%. Therefore, the central incident angle 55
The extinction ratio for incident light with a divergence angle of 5 degrees is 1 transmission.
0: 1 and reflection 50: 1.

The operation of the second embodiment will be described with reference to FIGS. The basic operation is the first
Since the embodiment is the same as that of the first embodiment, a duplicate description will be omitted. P
Of the read light incident on BS2, the multilayer mirror 21
The light mainly including the S-polarized light component reflected at a is emitted toward the SLM 1. The light amount of each polarized light component of this light is expressed as (0.018, 0.902) according to the above-mentioned format. The light quantity of each polarization component of the output light modulated by the SLM 1 is (0.902, 0.01) in the case of 100% modulation.
8), 0% modulation (0.018, 0.9)
02). This light enters the PBS 2a again and is partially reflected by the multilayer mirror 21a. As a result, PBS
Each polarized light component of the output light transmitted through 2a is 100
It becomes (0.886, 0.0018) with% modulated light and (0.018, 0.0886) with 0% modulated light. Since only the light of the P-polarized component is extracted from the polarizing plate 3a, the contrast ratio between the P-polarized light and the P-polarized light is 100% and 0%.
It is equal to the light quantity ratio of the polarized light components, and becomes 50: 1. Therefore, it is possible to improve the contrast ratio and realize a projector having a high output light intensity.

(Third Embodiment) The basic configuration of the projector according to the third embodiment is the same as that of the projector according to the first embodiment shown in FIG. PB of this embodiment
S2 is arranged so that the reading light is incident on the multilayer mirror 21 at an incident angle of 45 degrees.

Table 3 shows the structure of the multilayer mirror 21. The multilayer mirror 21 is configured by alternately stacking 27 layers of HfO ₂ and SiO ₂ . The triangular prism 22 is made of high refractive index glass.

[0036]

[Table 3]

FIG. 8 shows the spectral optical characteristics of the PBS2. As shown in FIG. 2A, in the case of S-polarized light, the reflectance in the visible light region is 98% or more, and the transmittance is 2% or less. On the other hand, as shown in FIG. 3B, in the case of P-polarized light, the reflectance in the visible light region is about 2% at an incident angle of 45 degrees, and about 4 to 10% with a deviation of ± 5 degrees. Has become. Therefore, the extinction ratio is about 50: 1 for transmitted light and about 10: 1 for reflected light.

In the projector using the PBS 2, a contrast ratio of 50: 1 is realized by the same operation as in the first embodiment.

(Fourth Embodiment) The basic configuration of a projector according to a fourth embodiment is the same as that of the projector according to the second embodiment shown in FIG. PB of this embodiment
S2a is that the read light is incident on the multilayer mirror 21 at an incident angle of 45
It is arranged to be incident in degrees.

Table 4 shows the configuration of the multilayer mirror 21a. The multilayer mirror 21a is configured by alternately stacking seven layers of TiO ₂ and CaF ₂ .

[0041]

[Table 4]

FIG. 9 shows the spectral optical characteristics of the PBS 2a. As shown in FIG. 3A, the reflectance in the visible light range in the case of S-polarized light is about 85 to 90%, and 10 to 15%.
% Of light is transmitted. On the other hand, as shown in FIG.
In the case of P-polarized light, the reflectance in the visible light range is about 1% at an incident angle of 45 degrees, and is about 5% even when it is shifted by ± 5 degrees. Therefore, the extinction ratio is about 8: 1 for transmitted light and about 40: 1 for reflected light.

In the projector using the PBS 2a, a contrast ratio of 40: 1 is realized by the same operation as in the second embodiment.

(Fifth Embodiment) In the above description, all the embodiments using a single-panel color projector have been described, but the present invention is also applicable to a three-panel color projector. FIG. 10 shows the configuration of a three-panel color projector according to a fifth embodiment of the present invention.

First, the configuration will be briefly described. The basic configuration is the same as that of the single-panel type color projector, and the description of the overlapping parts will be omitted. In the three-plate type projector, a dichroic mirror 41 and mirrors 43 and 44 for dividing the reading light for each wavelength component are arranged on the optical path of the reading light. Then, three sets of the SLM 1, the PBS 2, the CRT 37 and the like for generating a display image are provided for each wavelength component. Each PBS has the same characteristics as the first embodiment. On the output optical path, there are provided mirrors 45 and 46 for integrating the output lights of the respective wavelength components and a dichroic combiner 42, and on the output side of the dichroic combiner 42, a polarizing plate 3 for extracting only S-polarized light is provided. .

In this projector, the reading light is
The light is separated into each wavelength component of RGB by the dichroic mirror 41, and a part passes through mirrors 43 and 44, and SLM 1, PBS 2, FOP 36, C
The S-polarized light component having image information is formed and extracted by the RT 37. The light of each wavelength component is applied to mirrors 45 and 4.
The light is guided to a dichroic combiner 42 by 6 and condensed, and is enlarged as a color image by a projection lens 39 and projected on a screen 40.

Also in this device, the extinction ratio of the optical system is improved, so that the contrast ratio of the obtained color image can be improved.

In this embodiment, the polarizing plate is provided after synthesizing each monochromatic light. However, it may be provided on the output side of each PBS for each monochromatic light. Further, the configuration of each PBS may be such that the S-polarized light is guided to the SLM and the P-polarized light is extracted as an output as in the second embodiment. When used in a three-plate color projector, it is preferable to use a PBS having characteristics adapted to monochromatic light.

In the present invention, a polarizing plate is provided on the output side of the SLM.
Only one is provided. For this reason, the light amount loss due to the polarizing plate is small, and it is not necessary to greatly increase the output light intensity of the light source to achieve high output. For this reason, the amount of light absorbed by the polarizing plate can be small, so that the amount of heat generated due to light absorption is small, and a rise in the temperature of the polarizing plate can be avoided. In particular, since the polarizing plate is provided only on the output side of the PBS, the amount of light incident on the polarizing plate is reduced to about half or less even if the light source intensity is the same as compared with the case where the polarizing plate is provided on the input side of the PBS. As a result, the amount of light absorption is further reduced, and a rise in temperature can be prevented. Therefore, it is possible to prevent performance degradation due to the temperature rise of the polarizing plate. At the same time, it is easy to increase the output by increasing the output light intensity of the light source.

In the above description, an optical writing reflective spatial light modulator using a CRT as a writing light source has been described as an example. However, image writing is not limited to a CRT, and may be performed by a laser beam or the like. Further, in addition to optical writing, application to a projector using various reflective spatial light modulators, such as electrical writing, is possible.

[0051]

As described above, according to the present invention, since the extinction ratio of the entire system is adjusted by the PBS and the polarizing plate combined with the PBS, the output at the time of 0% modulation as the background light is obtained. While suppressing light, the intensity of output light at the time of 100% modulation can be kept high, and the contrast ratio is improved. In addition, since only one polarizing plate is disposed on the emission side of the PBS, deterioration due to temperature rise of the polarizing plate can be avoided, and performance can be stabilized, and high output can be achieved by increasing output light intensity of the light source. Easy.

[Brief description of the drawings]

FIG. 1 is a single-plate CRT-SL according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of an M-type color projector.

2 shows the arrangement of the PBS of the device according to FIG. 1;

FIG. 3 is a diagram showing spectral optical characteristics of a conventional PBS.

FIG. 4 is a diagram showing the spectral optical characteristics of the PBS of the device according to FIG. 1;

FIG. 5 is a single-plate CRT-SL according to a second embodiment of the present invention.
FIG. 2 is a configuration diagram of an M-type color projector.

6 shows the arrangement of the PBS of the device according to FIG.

FIG. 7 is a diagram showing the spectral optical characteristics of the PBS of the device according to FIG. 5;

FIG. 8 is a diagram illustrating spectral optical characteristics of a PBS according to a third embodiment.

FIG. 9 is a diagram illustrating spectral optical characteristics of a PBS according to a fourth embodiment.

FIG. 10 shows a three-plate CRT-S according to a fifth embodiment of the present invention.
FIG. 2 is a configuration diagram of an LM type color projector.

FIG. 11 is a cross-sectional view showing a configuration of a general PBS.

FIG. 12 is a configuration diagram of a conventional single-panel CRT-SLM type color projector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... SLM, 2 ... PBS, 3 ... Polarizer, 21 ... Multilayer mirror, 22, 23 ... Triangular prism, 31 ... White light source, 3
2 ... Collimate lens, 33 ... UV filter, 34 ...
IR filter, 35 ... tunable filter, 36 ... F
OP, 37 CRT, 38 controller, 39 projection lens, 40 screen, 41 dichroic mirror, 42 dichroic combiner, 43 to 46
…mirror.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/74 H04N 5/74 B

Claims (2)

[Claims] 1. A reflective spatial light modulator that emits output light generated by modulating read light incident from one surface from an incident surface of the read light, and a read light incident surface side of the optical modulator. Is disposed, and transmits the P-polarized light component of the incident light and reflects the S-polarized light component in a direction substantially perpendicular to the incident direction, so that the incident readout light goes straight and the incident output light is converted into the readout light. A polarizing beam splitter that separates and emits light in a direction substantially perpendicular to the polarizing beam splitter, and a polarizing plate that extracts an S-polarized component disposed on the optical path of the output light separated by the polarizing beam splitter. A projector characterized in that the transmittance of the S-polarized component is lower than the reflectance of the P-polarized component. 2. A reflection-type spatial light modulator for emitting output light generated by modulating read light incident from one surface from an incident surface of the read light, and a read light incident surface side of the optical modulator. Is disposed, and transmits the P-polarized component of the incident light and reflects the S-polarized component in a direction substantially perpendicular to the incident direction, thereby reflecting the read-out light incident in the direction perpendicular to the incident direction and entering the light. A polarizing beam splitter that transmits output light and separates and emits the read light, and a polarizing plate that extracts a P-polarized component disposed on the optical path of the output light separated by the polarizing beam splitter. The polarizing beam splitter, wherein the reflectance of the P-polarized light component is lower than the transmittance of the S-polarized light component.