JP2009042316A - Single plate type projector - Google Patents

Single plate type projector Download PDF

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Publication number
JP2009042316A
JP2009042316A JP2007204785A JP2007204785A JP2009042316A JP 2009042316 A JP2009042316 A JP 2009042316A JP 2007204785 A JP2007204785 A JP 2007204785A JP 2007204785 A JP2007204785 A JP 2007204785A JP 2009042316 A JP2009042316 A JP 2009042316A
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Japan
Prior art keywords
light
projection apparatus
apparatus according
filter member
polarization direction
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JP2007204785A
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Japanese (ja)
Inventor
Kazuaki Murayama
和章 村山
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Olympus Corp
オリンパス株式会社
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Priority to JP2007204785A priority Critical patent/JP2009042316A/en
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Abstract

An object of the present invention is to provide a small single-plate projector that projects a polarized image while maintaining the polarization of light from a light source appropriately.
A filter member that selectively converts the polarization direction of light emitted from a light source to a projection device that includes a spatial light modulator and a control circuit that controls the spatial light modulator, and a filter member The polarizing plate which permeate | transmits only the light of a specific polarization direction among the light which passed through.
[Selection] Figure 1A

Description

The present invention relates to a projection apparatus including a spatial light modulator.

  Among projection apparatuses, there is a single-plate projection apparatus having one spatial light modulator. The projection principle of the single-plate projector is as follows. First, one frame period for projecting one image is divided into subframe periods. Based on the divided subframes, the time for irradiating Red (R), Green (G), and Blue (B) light to the spatial light modulator is set. Then, the light of each color is sequentially applied to the spatial light modulator based on the time of the divided subframes. The spatial light modulator modulates the irradiated light. The image is then projected onto the screen by projecting the light modulated by the spatial light modulator onto the screen.

  In the projection of this single-plate projector, the subframe period is set sufficiently short. Therefore, the observer integrates the modulated light of each color in the brain and recognizes it as a color image as a result. The gradation here (that is, the number of reproduced colors in color display) is determined by the minimum time unit transmitted to the projection optical path of the light modulated by the spatial light modulator. That is, the gradation of the single-plate projector is determined depending on the response speed of the spatial light modulator. In view of this, in a single-plate projector, it is desirable to use a mirror device having a faster response speed than a liquid crystal device as a spatial light modulator. For example, Patent Document 1 discloses a single-plate projector provided with a DMD (Digital Micromirror Device).

  In addition, in the single-plate projector, a member that colors illumination light to Red (R), Green (G), and Blue (B) is necessary. Generally, a color wheel is used as this member, but there is a member called “Color Select” manufactured by Color Link as an alternative to this color wheel. This color select is a wavelength-selective polarizing element composed of laminated retardation plates. By using this color select, it is possible to output incident polarized light with its polarization direction rotated in a wavelength selective manner.

  On the other hand, a “polarizing screen” whose characteristics change depending on the polarization direction of incident light has been proposed as a projection screen corresponding to a single-plate projector. By using this polarizing screen, contrast can be improved. Although it is not always necessary to use polarized light for irradiating the mirror device, it is possible to improve the image quality of a projected image by using polarized light in consideration of using such a polarizing screen. In addition, by illuminating the mirror device with polarized light, the illumination light and the modulated light are separated by an optical element other than a TIR prism (Total Internal Reflection Prism) as in the case of the reflective liquid crystal device. You can also. Therefore, the freedom degree of selection of the structural member in a projection apparatus can be expanded.

Thus, there are several advantages to projecting a polarized image. Therefore, further technical development of a projection apparatus that projects polarized light is further desired.
JP 2002-333597 A

  It is an object of the present invention to provide a small single-plate projector that projects a polarized image while maintaining the polarization of light from a light source appropriately.

  A first aspect of the present invention includes a spatial light modulator, a control circuit that controls the spatial light modulator, a filter member that selectively converts the polarization direction of light emitted from a light source, and a filter member. Provided is a projection device including a polarizing plate that transmits only light in a specific polarization direction of light.

According to a second aspect of the present invention, there is provided the projection apparatus according to the first aspect of the present invention, further comprising a polarization conversion member that converts light emitted from a light source into a specific polarization direction.
According to a third aspect of the present invention, there is provided the projection apparatus according to the second aspect of the present invention, further comprising an integrator rod.

According to a fourth aspect of the present invention, there is provided a projection apparatus according to the first aspect of the present invention, wherein the number of spatial light modulators is one.
According to a fifth aspect of the present invention, in the projection apparatus according to the first aspect of the present invention, the filter member is a filter capable of converting a polarization direction of light having a wavelength of RED, light having a wavelength of GREEN, or light having a wavelength of BLUE. A projection apparatus including at least one of the above is provided.

According to a sixth aspect of the present invention, there is provided the projection apparatus according to the fifth aspect of the present invention, wherein each filter is controlled synchronously with the spatial light modulator.
According to a seventh aspect of the present invention, there is provided the projection apparatus according to the sixth aspect of the present invention, wherein the control circuit synchronously controls each filter and the spatial light modulator.

According to an eighth aspect of the present invention, there is provided the projection apparatus according to the first aspect of the present invention, wherein the spatial light modulator is a transmission type or a reflection type.
A ninth aspect of the present invention is the projection apparatus according to the eighth aspect of the present invention, wherein the spatial light modulator is an LCD (Liquid Crystal Device), LCOS (Liquid Crystal On Silicon), or a mirror device. I will provide a.

  According to a tenth aspect of the present invention, there is provided the projection apparatus according to the first aspect of the present invention, further comprising a TIR (Total Internal Reflection) prism.

  An eleventh aspect of the present invention provides the projection apparatus according to the first aspect of the present invention, further comprising a PBS (Polarization Beam Splitter) prism.

A twelfth aspect of the present invention provides the projection apparatus according to the first aspect of the present invention, wherein the filter member is disposed between the light source and the spatial light modulator.
A thirteenth aspect of the present invention provides the projection apparatus according to the first aspect of the present invention, wherein the filter member is arranged between the spatial light modulator and the screen.

A fourteenth aspect of the present invention provides the projection apparatus according to the thirteenth aspect of the present invention, wherein the filter member is disposed between the spatial light modulator and the polarizing plate.
According to a fifteenth aspect of the present invention, there is provided the projection apparatus according to the first aspect of the present invention, wherein the filter member can rotate on a plane perpendicular to the light traveling direction.

A sixteenth aspect of the present invention provides the projection apparatus according to the fifteenth aspect of the present invention, wherein the filter member is circular.
According to a seventeenth aspect of the present invention, there is provided the projection apparatus according to the first aspect of the present invention, wherein the filter member can slide on a plane perpendicular to the light traveling direction.

  According to an eighteenth aspect of the present invention, there is provided a method for projecting polarized light, comprising: wavelength-selectively converting a polarization direction of light; and transmitting only light having the wavelength-selectively converted polarization direction. .

  According to a nineteenth aspect of the present invention, a spatial light modulator, a control circuit that controls the spatial light modulator, a polarization conversion member that converts light emitted from a light source into a specific polarization direction, and identification of different incident frequencies are provided. There is provided a projection apparatus comprising: a filter member that rotates the polarization direction of the light converted into the polarization direction of the wavelength selectively, and a projection lens that projects the light through the filter member.

  According to a twentieth aspect of the present invention, there is provided the projection apparatus according to the nineteenth aspect of the present invention, further comprising a polarizing plate that reflects or removes a frequency other than one rotation direction of the light passing through the filter member. To do.

  According to a twenty-first aspect of the present invention, in the projection apparatus according to the twentieth aspect of the present invention, the filter member can rotate so that the polarization direction of light having only frequencies corresponding to RED, GREEN, and BLUE can be changed. And a projection device that irradiates the spatial light modulator with light having different polarization directions of RED, GREEN, and BLUE by switching each filter.

  According to a twenty-second aspect of the present invention, in the projection device according to the twenty-first aspect of the present invention, the spatial light modulator is controlled in synchronization with the light of each color, modulates the light of each color, and converts the modulated light of each color. A projection apparatus for sequentially projecting onto a screen is provided.

A twenty-third aspect of the present invention provides the projection apparatus according to the nineteenth aspect of the present invention, wherein the filter member is disposed between the light source and the spatial light modulator.
A twenty-fourth aspect of the present invention provides the projection apparatus according to the nineteenth aspect of the present invention, wherein the filter member is disposed between the spatial light modulator and the screen.

  A twenty-fifth aspect of the present invention provides the projection apparatus according to the twenty-first aspect of the present invention, wherein the filter member is a circular member that can rotate on a plane perpendicular to the light traveling direction.

  According to the present invention, it is possible to project light with polarization appropriately maintained on a screen. When this screen is a polarizing screen, the contrast of the projected image can be improved.

A projection apparatus according to an embodiment of the present invention described below includes a filter member that selectively converts the polarization direction of light emitted from a light source in terms of wavelength or frequency.
[Embodiment 1]
The configuration and projection principle of the single-plate projection apparatus according to Embodiment 1 will be described.

FIG. 1A shows a configuration of a single-plate projector 100a according to the first embodiment.
This single-plate projector 100a includes a light source 7, a polarization conversion member 8, a rod integrator 11, a color select wheel 12, a TIR (Total Internal Reflection) prism 19, a spatial light modulator, and spatial light (not shown). A control circuit that controls the modulator, a polarizing plate 21 and a projection lens 22 are included. In FIG. 1A, a mirror device 20 is used as an example of the spatial light modulator.

  The light source 7 plays a role of emitting light. As this light source, a mercury lamp that emits light including a plurality of wavelengths is used. In the first embodiment, a light source that emits light including a plurality of wavelengths and a plurality of polarization directions, such as a mercury lamp light source, is used.

  The polarization conversion member 8 plays a role of converting light emitted from the light source into a specific polarization direction. In the first embodiment, the polarization conversion member 8 includes a prism 9 having a PBS surface (Polarization Beam Splitter) that separates P-polarized light and S-polarized light, a reflecting portion provided on the prism, and a half-wave plate 10. is doing. For example, light emitted from a light source is incident on a prism having a PBS surface (Polarization Beam Splitter) that separates P-polarized light and S-polarized light. P-polarized light is transmitted as it is on the PBS surface, and S-polarized light is reflected. The transmitted P-polarized light is converted into S-polarized light by rotating the polarization direction by 90 ° by the half-wave plate 10 provided at the prism exit portion. On the other hand, the reflected S-polarized light is emitted in the same direction as the P-polarized light by a reflecting portion provided on the prism, for example, a mirror.

  The rod integrator 11 plays a role of making the illuminance of light uniform. The light incident on the rod integrator 11 repeats total internal reflection. This makes the illuminance of light uniform. The light with uniform illuminance is emitted from the exit surface of the rod integrator 11.

The arrangement of the polarization conversion member 8 and the rod integrator 11 may be reversed.
The color select wheel 12 is composed of a filter member 13. And it plays the role of converting the polarization direction of light in a wavelength selective manner. Preferably, the filter member 13 may include at least one filter portion that can convert only the polarization directions of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength. Particularly preferably, the filter member 13 may be composed of at least three types of rotatable filter parts 14, 15, and 16 that can convert the polarization directions of polarized light of frequencies corresponding to RED, GREEN, and BLUE.

  The TIR (Total Internal Reflection) prism 19 is composed of two triangular prisms, a first prism 17 and a second prism 18. The first prism 17 serves to totally reflect light incident at a critical angle or more. For example, the first prism 17 totally reflects incident light on an optical path incident on the reflective spatial light modulator. The totally reflected light is modulated by the reflective spatial light modulator and reflected toward the second prism 18. Then, the light is incident on the second prism 18 at a critical angle or less, so that the light is transmitted through the second prism 18. The second prism 18 plays a role of transmitting the reflected light modulated by the reflective spatial light modulator incident at a critical angle or less.

  The spatial light modulator plays a role of modulating incident light based on an image signal received from the control circuit. Examples of the spatial light modulator include, but are not limited to, a transmissive LCD (Liquid Crystal Device), a reflective LCOS (Liquid Crystal On Silicon), and a mirror device. In the projection apparatus of FIG. 1A, a mirror device 20 is used as a spatial light modulator. A projection apparatus provided with a plurality of spatial light modulators can be referred to as a multi-plate projection apparatus, and a projection apparatus provided with one spatial light modulator can be referred to as a single-plate projection apparatus. The projection apparatus according to the first embodiment is a single-plate projection apparatus 100 a that includes only one mirror device 20.

  A control circuit that controls a spatial light modulator (not shown) sends a control signal corresponding to image information to the spatial light modulator, and configures each light modulation element that constitutes the spatial light modulator, for example, the mirror device 20. It plays a role of controlling the operation of each mirror. Also, the operation timing of the spatial light modulator and the rotational position of the filter member 13 of the color select wheel 12 can be controlled synchronously. The synchronization control of the spatial light modulator and the filter member 13 of the color select wheel 12 can be performed with another circuit.

The polarizing plate 21 plays a role of transmitting only light having a specific polarization direction and reflecting or removing light having other polarization directions.
The projection lens 22 plays a role of projecting polarized light toward the screen.

The projection apparatus 100a according to the first embodiment is configured as described above.
Next, the principle of color image projection using the single-plate projector 100a of FIG. 1A will be described.
The light source 7 emits light 1 including a plurality of wavelengths and a plurality of polarization directions. Light 1 from the light source 7 is incident on a prism 9 having a PBS surface (Polarization Beam Splitter) that separates P-polarized light and S-polarized light of the polarization conversion member 8 that converts the light 1 into a specific polarization direction. In the light 1, P-polarized light and S-polarized light are separated on the PBS surface (Polarization Beam Splitter) of the prism. Here, the P-polarized light in the light 1 passes through the PBS surface. On the other hand, S-polarized light in the light 1 is reflected by the PBS surface. The P-polarized light transmitted through the PBS surface is converted into S-polarized light by rotating the polarization direction by 90 ° by the half-wave plate 10 provided at the exit portion of the prism 9. On the other hand, the reflected S-polarized light is emitted in the same direction as the P-polarized light by a reflecting portion, for example, a mirror, provided in the prism 9. By using the polarization conversion member 8 in this way, the light 1 can be aligned in a specific polarization direction. In the first embodiment, the polarization conversion member 8 converts light 1 from the light source into S-polarized light 2.

  The S-polarized light 2 emitted from the polarization conversion member 8 enters the rod integrator 11. The S-polarized light 2 incident on the rod integrator 11 repeats total internal reflection. This makes the illuminance of the S-polarized light 2 uniform. Then, the S-polarized light 2 with uniform illuminance is emitted from the exit surface of the rod integrator 11.

  The S-polarized light 2 emitted from the rod integrator 11 enters the color select wheel 12. The color select wheel 12 of FIG. 1A has a circular filter member 13 that can rotate on a plane perpendicular to the traveling direction of the light 2. The filter member 13 is configured by the filters 14, 15, and 16 that can convert only the polarization direction of any one of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength. Has been. That is, in FIG. 1A, a filter 14 that changes only the polarization direction of the light 3 having the RED wavelength from S-polarization to P-polarization, and a filter 15 that changes only the polarization direction of the light 4 having the GREEN wavelength from S-polarization to P-polarization, A filter member 13 is shown that is configured by a filter 16 that changes only the polarization direction 5 of the light of BLUE wavelength from S-polarized light to P-polarized light. Further, in FIG. 1A, the rotation of the filters 14, 15, and 16, that is, the switching of the filters, is synchronously controlled with the mirror device 20 by the control circuit (not shown).

FIG. 1A shows a case where only the polarization direction of the light 3 having the RED wavelength is changed from S-polarized light to P-polarized light.
The color select wheel 12 changes only the polarization direction of the light 3 having the RED wavelength from the S-polarized light to the P-polarized light by the filter 14 for the incident light 2 having only the S-polarized light. That is, based on the primary color of light, the light 3 with the RED wavelength becomes P-polarized light, and the light 4 with the GREEN wavelength and the light 5 with the BLUE wavelength maintain the S-polarized light.

  The light 6 in which only the light 3 having the RED wavelength is P-polarized light enters a first prism 17 of a TIR (Total Internal Reflection) prism 19. Then, the light 6 including P-polarized light is totally reflected by the first prism 17 toward the mirror device 20.

  The mirror device 20 modulates the incident light 6 with a control signal based on the image signal received from the control circuit. Here, the mirror device 20 is synchronously controlled with the filters 14, 15, 16 of the color select wheel 12 by the control circuit. That is, the modulation control of the light 6 by the mirror device 20 is performed in synchronization with the filter 14 that changes only the polarization direction of the light 3 having the RED wavelength from S-polarized light to P-polarized light. For example, in FIG. 1A, since the light 3 having the RED wavelength is changed to P-polarized light by the color select wheel 12, the control circuit transmits a control signal corresponding to the image signal based on the light 3 having the RED wavelength to the mirror device 20. Then, the mirror device 20 modulates the incident light 6 by a control signal corresponding to the image signal based on the received light 3 having the wavelength of RED.

The modulated light 6 is reflected toward the projection lens 22 by the mirror constituting the mirror device 20.
Then, the modulated light 6 is incident on the second prism 18 of a TIR (Total Internal Reflection) prism 19 at a critical angle or less, and is incident on the polarizing plate 21. The polarizing plate 21 transmits only light having a specific polarization direction. In other words, light having a frequency other than one rotation direction is reflected or removed. For example, in FIG. 1A, S-polarized GREEN wavelength light 4 and BLUE wavelength light 5 are reflected or removed while only P-polarized RED wavelength light 3 is transmitted.

The P-polarized RED wavelength light 3 that has passed through the polarizing plate 21 is projected onto a screen (not shown) via the projection lens 22, thereby projecting a red image.
Such projection is not limited to the light 3 of the RED wavelength, but by rotating the filter member 13 of the color select wheel 12 in synchronization with the control of the mirror device 20, the light 4 of the GREEN wavelength and the wavelength of the BLUE wavelength are rotated. The light 5 can be projected through the same process (process).

  Then, the light 3 with the wavelength of RED, the light 4 with the wavelength of GREEN, and the light 5 with the wavelength of BLUE are sequentially projected according to the subframe times of the light 3, 4, 5 of each color, It is possible to project a color image in which light of the same color is aligned with P deflection.

The above is the projection principle of the color image using the single-plate projector 100a of the first embodiment.
The light from the light source 7 can be converted into P-polarized light instead of being converted into S-polarized light shown in FIG. 1A by the polarization conversion member 8 that converts the light into a specific polarization direction. The filter member 13 of the color select wheel 12 is provided with each filter that changes any one of the polarization of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength from P-polarized light to S-polarized light. As a result, any of the P-polarized light of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength can be converted to S-polarized light. Then, by using the polarizing plate 21 configured to transmit only the S-polarized light, any one of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength, which has been changed to the S-polarized light. Only that light can be transmitted and projected onto the screen. In this way, by sequentially projecting light 3 of S-polarized RED wavelength, light 4 of GREEN wavelength, and light 5 of BLUE wavelength, a color image in which all colors of light are aligned in S-deflection is projected. can do.

Next, a modified example of the single-plate projector 100a according to the first embodiment will be described.
The first modification is an example in which the switching method of the color select wheel 12 is changed.
FIG. 1B shows a configuration of a single-plate projector 100b according to Embodiment 1 in which the color select wheel 12 is modified.

  The color select wheel 12a of FIG. 1B is different from the filter member 13 that rotates and switches the filters 14, 15, and 16 shown in FIG. 1A, and the filter member 13a that can slide to switch the filters 14a, 15a, and 16a. It is configured. For example, the filter member 13a of the color select wheel 12a in a plane perpendicular to the traveling direction of the light 2 in association with the switching of the polarization direction of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength. Each filter 14a, 15a, 16a is switched by sliding the filter 14a, 15a, 16a up and down or left and right.

  The other components in FIG. 1B are the same as in FIG. Note that the shape of the color select wheel, the shape of the filter member, and the filter in the embodiments of the present specification may be changed as appropriate.

A color image can be projected even with such a configuration in which the color select wheel is modified.
The second modification is an example in which the arrangement of the color select wheel 12 is changed.

FIG. 1C shows the configuration of the single-plate projector 100c according to Embodiment 1 in which the arrangement of the color select wheel 12 is changed.
1C differs from FIG. 1A in which the color select wheel 12 is disposed between the light source 7 and the mirror device 20, and the color select wheel 12 is disposed between the mirror device 20 and a screen (not shown). . In particular, in FIG. 1C, the color select wheel 12 is disposed between the mirror device 20 and the polarizing plate 21, and the TIR prism 19 is provided between the mirror device 20 and the color select wheel 12.

The other components in FIG. 1C are the same as in FIG.
In the single-plate projection device 100c of FIG. 1C, the light 1 emitted from the light source 7 is incident on the polarization conversion member 8 and is converted into only S-polarized light 2.

  The light 2 having only S polarization enters the mirror device 20 via the rod integrator 11 and the first prism 17 of the TIR prism 19. The light 2 incident on the mirror device 20 is modulated by the mirror of the mirror device 20 and reflected to the projection optical path. The reflected light 2 passes through the second prism 18 of the TIR prism 19 and enters the color select wheel 12. Then, the color selection wheel 12 changes the polarization direction of any one of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength in the light 2 from S-polarized light to P-polarized light. The light 6 containing P-polarized light passes through the color select wheel 12 and enters the polarizing plate 21. Then, the polarizing plate 21 is configured to reflect the S-polarized light and transmit only the P-polarized light, so that the light 3 having the RED wavelength and the GREEN wavelength of the light 6 including the P-polarized light. Only the light 4 or the BLUE wavelength light 5 passes through the polarizing plate 21. The transmitted light is projected onto a screen (not shown) via the projection lens 22.

  As described with reference to FIG. 1A, a color image is obtained by sequentially projecting the projections of such modulated light beams 3, 4, 5 according to the time of subframes corresponding to the light beams 3, 4, 5 of each color. Can be projected.

The third modification is an example in which the TIR prism 19 is replaced with another optical element.
FIG. 1D is a configuration diagram of a single-plate projector 100d according to Embodiment 1 in which the TIR prism 19 is replaced with a PBS prism 23.

  FIG. 1D shows a configuration in which a PBS prism 23 is used instead of the TIR prism 19 shown in FIG. 1A. By using the PBS prism 23, the light transmittance is improved as compared with the TIR prism 19. Further, by using the PBS prism 23, it is not necessary to separate the pupil of the incident light to the mirror device 20 and the reflected light from the mirror device 20, so that the total reflection condition is relaxed and the internal configuration of the projection apparatus 100d is designed. It becomes easy.

The other components in FIG. 1D are the same as in FIG.
In the single-plate type projector 100d of FIG. 1D, the light 1 emitted from the light source is incident on the polarization conversion member 8, and is converted into only the S-polarized light 2. The light 2 that is only S-polarized light enters the color select wheel 12 via the rod integrator 11. Then, the polarization direction of any one of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength is changed from the S-polarized light by the color select wheel 12. It can be changed to P-polarized light. The light 6 including P-polarized light enters the PBS prism 23. Then, the S-polarized light 4 and 5 in the light 6 including P-polarized light is transmitted by the polarization separation filter of the PBS prism 23, and only the P-polarized light 3 is reflected toward the mirror device 20. The P-polarized light 3 incident on the mirror device 20 is modulated by the mirror of the mirror device 20 and reflected to the projection optical path. The reflected light 3 enters the polarizing plate 21 so as not to enter the PBS prism 23. The polarizing plate 21 is configured to reflect S-polarized light and pass only P-polarized light. Since the reflected light 3 is P-polarized light, it passes through the polarizing plate 21. The light 3 transmitted through the polarizing plate 21 is projected onto a screen (not shown) via the projection lens 22.

  As described with reference to FIG. 1A, by sequentially projecting such modulated light beams 3, 4, and 5 in accordance with the time of the subframes corresponding to the light beams 3, 4, and 5 of each color, it is aligned with the P deflection. A color image can be projected onto the screen.

Further, when the PBS prism 23 is used, an image can be projected without using the polarizing plate 21.
In the first embodiment, by changing the order of the projection lens 22 and the polarizing plate 21, light is first incident on the projection lens 22, and thereafter, only the P-polarized light is transmitted by the polarizing plate 21. Such a configuration can also be adopted.
[Embodiment 2]
The configuration and projection principle of the single-plate projector according to the second embodiment will be described.

  Unlike the single-plate projector of the first embodiment, the single-plate projector of the second embodiment uses LCOS (Liquid Crystal On Silicon) as a reflective spatial light modulator. The polarizing plate is configured to transmit S-polarized light and reflect or remove P-polarized light.

Since the other components of the second embodiment are the same as those of the first embodiment, description thereof is omitted.
An image projection principle using the single-plate projection apparatus according to the second embodiment will be described.

FIG. 2 is a configuration diagram of a single-plate projector 200 in which the spatial light modulator is replaced by the LCOS 24 from the mirror device 20 of FIG. 1D.
In the single-plate projection device 200 of FIG. 2, the light 1 emitted from the light source 7 is converted into S-polarized light 2 by entering the polarization conversion member 8. Then, the light 2 that is only S-polarized light enters the color select wheel 12 via the rod integrator 11. Then, the polarization direction of any one of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength is changed from the S-polarized light by the color select wheel 12. It can be changed to P-polarized light. The light 6 including P-polarized light enters the PBS prism 23. By the polarization separation filter of the PBS prism 23, the S-polarized light 4 and 5 in the light 6 including the P-polarized light is transmitted, and only the P-polarized light 3 is reflected toward the LCOS 24. The P-polarized light 3 incident on the LCOS 24 is modulated by the LCOS 24, and the P-polarized light becomes S-polarized light. Then, the light 3 that has become S-polarized light is reflected to the projection optical path. The reflected light 3 passes through the polarization separation filter of the PBS prism 23 and enters the polarizing plate 21. Then, by configuring the polarizing plate 21 so as to reflect the P-polarized light and transmit only the S-polarized light, only the light 3 that is S-polarized light is transmitted through the polarizing plate 21. The transmitted S-polarized light 3 is projected through a projection lens 22 onto a screen (not shown).

  As described with reference to FIG. 1A, according to the time of subframes corresponding to the light beams 3, 4, and 5 of each color, the light beams 3, 4, and 5 thus modulated are sequentially projected to achieve S deflection. A color image can be projected.

In addition, when the PBS prism 23 is used in this way, an image can be projected without using the polarizing plate 21.
In the second embodiment, the order of the projection lens 22 and the polarizing plate 21 is changed so that the light enters the projection lens 22 first, and then only the S-polarized light is transmitted by the polarizing plate 21. Such a configuration can also be adopted.
[Embodiment 3]
The configuration and projection principle of the single-plate projector according to Embodiment 3 will be described.

  Unlike the single-plate projector of the first embodiment, the single-plate projector of the third embodiment uses a transmissive LCD (Liquid Crystal Device) instead of the reflective mirror device 20 as a spatial light modulator. ing. The polarizing plate 21 is configured to transmit S-polarized light and reflect or remove P-polarized light.

Since the other components of the third embodiment are the same as those of the first embodiment, description thereof is omitted.
An image projection principle using the single-plate projection device of the third embodiment will be described.

FIG. 3 is a configuration diagram of a single-plate projector 300 in which the spatial light modulator is replaced by the transmissive LCD 25 from the mirror device 20 of FIG. 1D.
In the single-plate projector 300 of FIG. 3, the light 1 emitted from the light source 7 is converted into only the S-polarized light 2 by entering the polarization conversion member 8. Then, the light 2 that is only S-polarized light enters the color select wheel 12 through the rod integrator 11. By the color select wheel 12, the polarization direction of any one of the light 3 having the RED wavelength, the light 4 having the GREEN wavelength, and the light 5 having the BLUE wavelength is changed from the S-polarized light to the P-polarized light. Can be changed. Then, the light 6 including P-polarized light enters the PBS prism 23. Then, the S-polarized light 4 and 5 in the light 6 including P-polarized light is transmitted by the polarization separation filter of the PBS prism 23, and only the P-polarized light 3 is reflected toward the LCD 25. The P-polarized light 3 incident on the LCD 25 is modulated by the LCD 25 and the P-polarized light is changed to S-polarized light. The S-polarized light 3 modulated by the LCD 25 is transmitted to the projection optical path. The transmitted S-polarized light 3 enters the polarizing plate 21. Then, by configuring the polarizing plate 21 so as to reflect the P-polarized light and transmit only the S-polarized light, the light 3 that is S-polarized light is transmitted through the polarizing plate 21. In this way, the light 3 transmitted through the polarizing plate 21 is projected onto a screen (not shown) via the projection lens 22.

  As described with reference to FIG. 1A, according to the time of subframes corresponding to the light beams 3, 4, and 5 of each color, the light beams 3, 4, and 5 thus modulated are sequentially projected to achieve S deflection. A color image can be projected.

In addition, when the PBS prism 23 is used in this way, an image can be projected without using the polarizing plate 21.
In the third embodiment, the order of the projection lens 22 and the polarizing plate 21 is changed so that the light enters the projection lens 22 first, and then only the S-polarized light is transmitted by the polarizing plate 21. Such a configuration can also be adopted.

  As described above, the spatial light modulator, the control circuit that controls the spatial light modulator, the filter member that selectively converts the polarization direction of the light emitted from the light source, and the specific polarization of the light that passes through the filter member A projection apparatus is described that includes a polarizing plate that transmits only light in a direction. With such a configuration of the projection apparatus, it is possible to project a polarized image in which the polarization of light from the light source is appropriately maintained without increasing the size of the projection apparatus. When a polarizing screen is used as the screen for the projection apparatus, the contrast of the projected image can be improved.

1 is a configuration diagram of a single-plate projector according to Embodiment 1. FIG. It is a block diagram of the single-plate-type projector of the 1st modification of Embodiment 1 which changed the switching system of the color select wheel. It is a block diagram of the single-plate-type projector of the 2nd modification of Embodiment 1 which changed arrangement | positioning of the color select wheel. It is a block diagram of the single-plate-type projector of the 3rd modification of Embodiment 1 which replaced the TIR prism with the PBS prism. It is a block diagram of the single-plate-type projection apparatus of Embodiment 2 which replaced the spatial light modulator with LCOS from the mirror device of FIG. 1D. It is a block diagram of the single-plate-type projection apparatus of Embodiment 3 which replaced the spatial light modulator with LCD from the mirror device of FIG. 1D.

Explanation of symbols

1 Light from light source (P-polarized light + S-polarized light)
2 Light of S polarization 3 Light of wavelength of RED 4 Light of wavelength of GREEN 5 Light of wavelength of BLUE 6 Light including RED, GREEN, BLUE 7 Light source 8 Polarization conversion member 9 PBS surface for separating P polarization and S polarization ( Prism having Polarization Beam Splitter 10 Half-wave plate 11 Rod integrator 12 Color select wheel 12a Color select wheel 13 Filter member 13a Filter member 14 Filter 14a for changing only the polarization direction of light of RED wavelength from S-polarized light to P-polarized light A filter that changes only the polarization direction of light with a wavelength of RED from S-polarized light to P-polarized light 15 A filter that changes only the polarization direction of light with a wavelength of GREEN from S-polarized light to P-polarized light 15a Only the polarization direction of light with a wavelength of GREEN is S-polarized light To change from P to P polarization 16a Filter that changes only the polarization direction of light of the blue wavelength from S-polarized light to P-polarized light 16a Filter that changes only the polarization direction of light of the blue wavelength light from S-polarized light to P-polarized light 17 Configures a TIR (Total Internal Reflection) prism First prism 18 Second prism constituting a TIR (Total Internal Reflection) prism 19 TIR (Total Internal Reflection) prism 20 Mirror device 21 Polarizing plate 22 Projection lens 23 PBS (Polarization Beam Split) Pr ic 24 Slit 24 LC
25 LCD (Liquid Crystal Device)
100a Single-plate projector 100b Single-plate projector 100c Single-plate projector 100d Single-plate projector 200 Single-plate projector 300 Single-plate projector

Claims (25)

  1. A projection apparatus comprising a spatial light modulator and a control circuit for controlling the spatial light modulator,
    A filter member that selectively converts the polarization direction of the light emitted from the light source;
    A polarizing plate that transmits only the light in a specific polarization direction out of the light through the filter member;
    A projection apparatus comprising:
  2. A polarization conversion member that converts light emitted from the light source into a specific polarization direction;
    The projection apparatus according to claim 1, further comprising:
  3.   The projection apparatus according to claim 1, further comprising a rod integrator.
  4. The spatial light modulator is one;
    The projection apparatus according to claim 1.
  5. The filter member includes at least one filter capable of converting a polarization direction of light having a wavelength of RED, light having a wavelength of GREEN, or light having a wavelength of BLUE.
    The projection apparatus according to claim 1.
  6. The rotation of each filter is synchronously controlled with the operation control of the spatial light modulator.
    The projection apparatus according to claim 5, wherein:
  7. The control circuit synchronously controls rotation of each filter and operation control of the spatial light modulator;
    The projection apparatus according to claim 6.
  8. The spatial light modulator is transmissive or reflective;
    The projection apparatus according to claim 1.
  9. The spatial light modulator is an LCD (Liquid Crystal Device), an LCOS (Liquid Crystal On Silicon), or a mirror device.
    The projection apparatus according to claim 8.
  10.   The projection apparatus according to claim 1, further comprising a TIR (Total Internal Reflection) prism.
  11.   The projection apparatus according to claim 1, further comprising a PBS (Polarization Beam Splitter) prism.
  12. The filter member is disposed between the light source and the spatial light modulator;
    The projection apparatus according to claim 1.
  13. The filter member is disposed between the spatial light modulator and a screen;
    The projection apparatus according to claim 1.
  14. The filter member is disposed between the spatial light modulator and the polarizing plate.
    The projection apparatus according to claim 13.
  15. The filter member can rotate in a plane perpendicular to the traveling direction of the light;
    The projection apparatus according to claim 1.
  16. The filter member is circular,
    The projection apparatus according to claim 15.
  17. The filter member can slide on a plane perpendicular to the traveling direction of the light.
    The projection apparatus according to claim 1.
  18. A projection method for projecting polarized light,
    Converting the polarization direction of light in a wavelength selective manner;
    Transmitting only the light whose polarization direction has been converted in a wavelength selective manner;
    A projection method comprising:
  19. A projection apparatus comprising a spatial light modulator and a control circuit for controlling the spatial light modulator,
    A polarization conversion member that converts light emitted from the light source into a specific polarization direction;
    A filter member that rotates the polarization direction of the light that has been converted into the specific polarization direction at different frequencies and outputs the light by selectively rotating the wavelength direction;
    A projection lens that projects the light through the filter member;
    A projection apparatus comprising:
  20. A polarizing plate that reflects or removes a frequency other than one rotation direction of the light through the filter member,
    The projection apparatus according to claim 19, further comprising:
  21. The filter member is composed of at least three types of rotatable filters that can change the polarization direction of light of each frequency corresponding to RED, GREEN, and BLUE, and the RED, Irradiating the spatial light modulator with light having a different polarization direction of any of GREEN and BLUE;
    21. The projection apparatus according to claim 20, wherein
  22. The spatial light modulator is controlled in synchronization with the light of each color, modulates the light of each color, and sequentially projects the modulated light of each color on a screen;
    The projection apparatus according to claim 21, wherein:
  23. The filter member is disposed between the light source and the spatial light modulator;
    The projection apparatus according to claim 19.
  24. The filter member is disposed between the spatial light modulator and a screen;
    The projection apparatus according to claim 19.
  25. The filter member is a circular member that is rotatable in a plane perpendicular to the traveling direction of the light.
    The projection apparatus according to claim 24.
JP2007204785A 2007-08-06 2007-08-06 Single plate type projector Withdrawn JP2009042316A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007204785A JP2009042316A (en) 2007-08-06 2007-08-06 Single plate type projector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2007204785A JP2009042316A (en) 2007-08-06 2007-08-06 Single plate type projector

Publications (1)

Publication Number Publication Date
JP2009042316A true JP2009042316A (en) 2009-02-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
JP2007204785A Withdrawn JP2009042316A (en) 2007-08-06 2007-08-06 Single plate type projector

Country Status (1)

Country Link
JP (1) JP2009042316A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101859052A (en) * 2009-04-01 2010-10-13 精工爱普生株式会社 Projector
WO2014064743A1 (en) * 2012-10-22 2014-05-01 Necディスプレイソリューションズ株式会社 Projector

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101859052A (en) * 2009-04-01 2010-10-13 精工爱普生株式会社 Projector
US8322859B2 (en) 2009-04-01 2012-12-04 Seiko Epson Corporation Projector
WO2014064743A1 (en) * 2012-10-22 2014-05-01 Necディスプレイソリューションズ株式会社 Projector
US9529247B2 (en) 2012-10-22 2016-12-27 Nec Display Solutions, Ltd. Projector including polarization separation element and rotating prism

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