JP2017054061A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector that eliminates a color braking phenomenon, while ensuring excellent gradation characteristics.SOLUTION: A projector comprises: an image synthesis element 121 that synthesizes image light incident upon each of a plurality of incidence surfaces, and emits synthesized light from an emission surface; a light source 11 that emits first to third color light different in color, emits the first and second color light in a first direction 1101 in time series, and emits the third color light in a second direction 1102; a first spatial optical modulator 111 and second spatial optical modulator 120 that are provided between the first incidence surface of the image synthesis element 121 and the light source 11, and modulate the first color light and second color light to be made incident in time series, to generate first image light and second image light; a third spatial optical modulator 112 that is provided between the second incidence surface of the image synthesis element 121 and the light source 11, and modulates the third color light to be made incident, to generate third image light; and lens systems 114 and 116 that conjugate with the first spatial optical modulator 111 and second spatial optical modulator 120.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projector, and more particularly to a three-plate projector that includes three display elements and projects color image light obtained by synthesizing image light obtained by irradiating these display elements with red, green, and blue light. About.

A projector using a spatial light modulator is known. The spatial light modulator is irradiated with color light such as red (R), blue (B), and green (G), and image light modulated by the spatial light modulator is enlarged and projected onto a screen. A three-plate type using three spatial light modulators and a single-plate type using a single spatial light modulator are known. In the three-plate type, three spatial light modulators are provided corresponding to three color lights of red, blue, and green. As the spatial light modulator, a liquid crystal panel, DMD (Digital Mirror Device: Digital Mirror Device of Texas Instruments, USA), LCOS (Liquid crystal on silicon), and the like are known. These known techniques will not require further explanation.
By the way, in the patent document 1, the present applicant uses an LED (Light Emitting Diode) as a solid source as a light source and irradiates blue light and green light in a time-sharing manner as a projector using a cross dichroic prism. It has been proposed to realize a bright projector with excellent color reproducibility by synchronously controlling the driving of the liquid crystal panel according to the irradiation of each color light.

Regardless of whether a liquid crystal panel, DMD, or LCOS is used as the spatial light modulator, if a projector configuration is used in which a single spatial light modulator is irradiated with a plurality of color lights in a time-sharing manner, the color braking phenomenon Will occur. It is important to brighten the projected image, but naturally the image quality is also important, and it is desirable to avoid the deterioration of the image quality due to the occurrence of the color breaking phenomenon.
Various methods are known for improving the degradation of image quality due to the color braking phenomenon. Lights when a solid-state light source is used as the light source and the driving frequency (lighting frequency) of the light source that sequentially generates red, green, and blue light is synchronized with the refresh rate that is the driving frequency of the spatial light modulator. Increasing the frequency and refresh rate improves the color braking phenomenon. It is said that driving at 540 Hz or higher has a great effect on improving the color braking phenomenon (see paragraph 0006 of Patent Document 2).

When the refresh rate is increased in order to reduce the color braking phenomenon, a new problem that the image quality deteriorates may occur. That is, the response speed cannot be sufficiently coped with in the case of a spatial light modulator using a liquid crystal in response to a high refresh rate. In the case of DMD, the on / off speed of a micromirror as a device characteristic. In other words, the gradation characteristics in PWM drive are degraded. The mechanical switching speed of the DMD mirror is said to be about 15 μs (see Non-Patent Document 1).
The DMD is said to be capable of displaying an image of 256 gradations of 60 frames per second at a frequency of about 300 Hz (see Non-Patent Document 2).

As described above, when using a liquid crystal or a DMD as a spatial light modulator, there is a limit to the response speed of the device, so if color switching is performed too fast, It happens that the response cannot keep up. As a result, the gradation display cannot be sufficiently performed, and the image quality may be deteriorated.
Also in the configuration disclosed in Patent Document 1, green light and blue light are irradiated on a common liquid crystal panel in a time-sharing manner. For this reason, although the color braking phenomenon is improved by switching the color light at a high speed, there is still room for improvement in the gradation display characteristics. Especially for blue light, the light emission time (irradiation time) is set to be shorter than other color light from the viewpoint of weight balance, so when driving to further shorten the light emission time to improve the color braking phenomenon, The gradation characteristics are deteriorated.

International Publication No. 2012/086011 Japanese Patent No. 5157542

Vacuum magazine Vol. 43, no. 2,2000 pp119-125 2000 IEICE General Conference SC-7-4 pp215-216

As described above, when the lighting frequency and the refresh rate are increased in order to reduce the color braking phenomenon, the gradation characteristics are deteriorated from the operation characteristics of the display panel, and the image quality may be lowered.
The present invention realizes a projector having good gradation characteristics while eliminating the color braking phenomenon.

The projector according to the present invention includes a plurality of incident surfaces and an output surface, and combines an image light incident on each of the plurality of incident surfaces to emit from the output surface;
First to third color lights of different colors are emitted, the first color light and the second color light are emitted in time series in a first direction, and the third color light is different from the first direction. A light source that emits in the direction of 2;
The first image light and the second color light are modulated between the first color light and the second color light that are provided between the first incident surface of the image composition element and the light source and are incident in time series. A first spatial light modulator and a second spatial light modulator that generate image light;
A third spatial light modulator that is provided between the second incident surface of the image composition element and the light source and modulates the incident third color light to generate third image light;
A lens system conjugate of the first spatial light modulator and the second spatial light modulator;
Have

  In the projector of the present invention configured as described above, the color braking phenomenon is eliminated, and at the same time, the gradation characteristics are improved.

It is a block diagram which shows the structure of the optical system of 1st Embodiment of the projector by this invention. It is a block diagram which shows the structure of the optical system of 2nd Embodiment of the projector by this invention. 3 is a block diagram illustrating a configuration of a light source unit 11. FIG. It is a block diagram which shows the structure of the optical system of 3rd Embodiment of the projector by this invention. It is a block diagram which shows the structure of the optical system of 4th Embodiment of the projector by this invention. It is a block diagram which shows the other structure of the light source part. It is a figure which shows the structure of the polarization beam splitter 308 in FIG. It is a figure which shows the combination state of TIR prisms 108, 109, 110, and 119 and DMD display panel which are used in 1st Embodiment. (A) is a figure which shows the incident light to the cross dichroic prism 121, (b) is a figure which shows the transmission characteristic of the cross dichroic prism 121. FIG.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an optical system of a first embodiment of a projector according to the present invention.
In the present embodiment, the light source unit 11, the illumination lenses 101, 102, 105, 106, and 107, the reflection mirror 104, the polarizing beam splitter 103, the TIR prisms 108, 109, 110, and 119, the DMD display panel 111, 112, 113, 120, lenses 114, 116, 118, reflection mirrors 115, 117, a cross dichroic prism 121, and a projection lens 122.
The DMD display panel 113 as the fourth spatial light modulator is for green light, and the DMD display panel 112 as the third spatial light modulator is for red light. The DMD display panel 111, which is the first spatial light modulator, serves both for blue light and green light for the first modulation. The DMD display panel 120, which is the second spatial light modulator, is used for the second modulation and serves both for blue light and blue light.

Blue image light and green image light modulated by the DMD display panel 111 and the DMD display panel 120 are incident on the first incident surface of the cross dichroic prism 121 serving as an image composition element in time series. Red image light modulated by the DMD display panel 112 is incident on the second incident surface facing the incident surface. Green image light modulated by the DMD display panel 113 is incident on a third incident surface orthogonal to the first incident surface and the second incident surface. These image lights are combined by a cross dichroic prism 121 and emitted toward a screen (not shown) via a projection lens 122.
Although the configuration of the light source unit 11 will be described later, the light source unit 11 generates S-polarized red light, P-polarized light, S-polarized green light, and S-polarized blue light. The exit path of S-polarized red light from the light source unit 11 is the direction 1101 in FIG. The emission paths of P-polarized light, S-polarized green light, and S-polarized blue light from the light source unit 11 are in the direction 1102 in FIG.

FIG. 3 is a block diagram illustrating a configuration of the light source unit 11.
The light source unit 11 includes an LED light source that generates monochromatic light, and includes two LED light sources 31 that generate green light, an LED light source 32 that generates red light, and an LED light source 33 that generates blue light. Each LED light source is provided with a lens 301 for collimating the LED light.
The light source unit 11 includes dichroic mirrors 302 and 303, fly-eye lenses 304 and 305, polarization conversion elements 306 and 307, a polarization beam splitter 308, and a phase difference plate 309.
An LED light source that emits a single color was used. Two LED light sources 31 that emit green light are provided, and one LED light source 32 that emits red light and one LED light source 33 that emits blue light are provided. Such LEDs that emit color light in the red, green, and blue bands are readily available, and those with extremely high luminance are also known.
In general, the emission characteristics of an LED have a forward spread, so that the LED light can be used effectively by arranging a lens system in the vicinity of the LED light source. Although a single lens 301 is shown in FIG. 3, a single lens is not necessarily optimal. As described above, the LED radiation characteristic spreads in the forward direction and the radiation angle is large. Therefore, the lens system may be composed of a plurality of lenses.

The dichroic mirror 303 is used for synthesizing the green light from the LED light source 31 and the red light from the LED light source 32, and is a well-known technique as a component of the optical system of the projector. The dichroic mirror 302 is used to synthesize green light from the LED light source 31 and blue light from the LED light source 33.
The polarization conversion elements 306 and 307 used in combination with the fly-eye lenses 304 and 305 are provided with a plurality of retardation plates and are generally used in a liquid crystal projector to unify the polarization direction of non-polarized light. It has been broken.
In the optical system shown in FIG. 3, green light emitted from one LED light source 31 and red unpolarized light emitted from the LED light source 32 are unified into P-polarized light by the polarization conversion element 307. The green light emitted from the other LED light source 31 and the blue light emitted from the LED light source 33 are unified into S-polarized light by the fly-eye lenses 304 and 305 and the polarization conversion element 306. Therefore, the polarization plate 307 and 306 are attached so that the phase difference plates provided are different in direction.

FIG. 6 is a diagram showing a configuration of the polarization beam splitter 308 in FIG.
As shown in FIG. 6, the polarization beam splitter 308 has a property of transmitting P-polarized light and reflecting S-polarized light with respect to green and blue band light, and reflects red and reflects green. A dichroic mirror 61 having a transmission characteristic is integrated. As such a polarization beam splitter, a wire grid type has been put into practical use.
The dichroic mirror 61 and the polarization beam splitter 62 may be disposed close to each other and independently disposed with a predetermined air interval. A wire grid type polarization beam splitter generally has a wire grid formed on one side of a transparent substrate or the like, and a dichroic mirror is formed on a plane on the side where the wire grid is not formed, and may be integrated. it can.
As described above, only the P-polarized red light emitted from the light source device 11 is different in traveling direction from the other color lights (P-polarized light and S-polarized green light, and S-polarized blue light). These proceed in a direction away from each other while maintaining an orthogonal relationship. Note that the polarization direction of P-polarized red light is converted to S-polarized light by the phase difference plate 309. Further, the light from the light source device 11 illuminates the DMD panels 111, 112, and 113 with illumination lenses 101, 102, 105, 106, and 107, and the like.

Next, the operation of this embodiment will be described. First, the light source device 11 generates P-polarized light and S-polarized green light, S-polarized blue light, and S-polarized red light. Furthermore, it is preferable that the S-polarized green light and blue light are lit in a time-sharing manner so that the lighting periods do not overlap. This is because the DMD 111 and the DMD 120 are irradiated with S-polarized green light and blue light. When the lighting periods overlap, the color purity of the projected image is reduced. Therefore, the overlapping of the lighting periods may be determined by design specifications according to an allowable range. Further, S-polarized red light and P-polarized green light from the light source unit 11 are always emitted.
The S-polarized red light illuminates the DMD display panel 112 through the illumination lens 102, the illumination lens 106, and the mirror 104 disposed in the middle. The DMD display panel 112 is arranged in combination with the TIR prism 109.

FIG. 7 is a diagram showing a combination state of the TIR prisms 108, 109, 110, and 119 and the DMD display panel used in the present embodiment.
In each TIR prism, as shown in FIG. 7, two triangular prisms 701 and 702 are arranged with a minute air interval. Incident light is totally reflected by the prism 701 to the DMD display panel 703 side. In this structure, the modulated light after light modulation by the DMD display panel 703 is totally reflected by the prism 702 and taken out. As the light traveling direction, since the incident direction and the exit direction are the same direction, the optical system can have a linear layout, which is very convenient for the optical system using the cross dichroic prism as in this embodiment. Is good.
In the present embodiment, red light is modulated by the DMD display panel 112, then enters the cross dichroic prism 121, merges with light from other optical systems, and is enlarged and projected by the projection lens 122.

Next, P-polarized green light emitted from the light source unit 11 will be described. P-polarized green light is always emitted, and the illumination lenses 101 and 107 illuminate the DMD display panel 113. For the bending of the optical path, a wire grid type polarization beam splitter 103 was used. The wire grid type polarization beam splitter 103 can reflect the P-polarized light and transmit the S-polarized light by setting the longitudinal direction of the wire in a predetermined arrangement with respect to the polarization vibration direction.
The modulated light from the DMD display panel 113 is incident on the cross dichroic prism 121 by the TIR prism 110 in the same manner as the modulated light from other DMD display panels, and is photo-combined and enlarged and projected by the projection lens 122.
The S-polarized blue light and the S-polarized green light from the light source unit 11 illuminate the DMD display panel 111 as the first spatial light modulator by the illumination lenses 101 and 105. A TIR prism 108 is disposed on the DMD 111. The light modulated by the DMD display panel 111 illuminates the DMD display panel 120 as a second spatial light modulator by the relay lens systems 114, 116, and 118. Reflecting mirrors 115 and 117 are provided between the relay lens systems, and the traveling path of the illumination light is bent. In addition, a TIR prism 119 is disposed in front of the DMD display panel 120 in the same manner as other DMD display panels.
Note that the resolution of the DMD display panel 111 of the first spatial light modulator and the resolution of the DMD display panel 120 of the second spatial light modulator are not necessarily the same. Further, the display area size of the DMD display panel need not be the same. The three DMD display panels surrounding the cross dichroic prism 121 are preferably DMD display panels having the same specifications.

The optical parameters of the relay lens system are determined so that the DMD 111 of the first spatial light modulator and the second spatial light modulator 120 have a conjugate relationship. By adopting such a configuration, the green light component that determines most of the brightness can be obtained and used from two systems as compared with a normal three-plate projector, so that the amount of green light increases, resulting in a high level of light. A bright projector can be realized.
The reason will be described with reference to FIG. FIG. 8A is a diagram showing light incident on the cross dichroic prism 121, and FIG. 8B is a diagram showing transmission characteristics of the cross dichroic prism 121.
As shown in FIG. 8A, P-polarized green light and S-polarized green light are incident on the B reflecting surface of the cross dichroic prism 121. FIG. 8B shows the wavelength transmission characteristics of the B reflection surface of the cross dichroic prism 121. As shown in the figure, the S-polarized light is designed to reflect the green light band as shown by the characteristic 801, and the P-polarized light is transmitted through the green light band as shown by the characteristic 802. Designed to. A cross dichroic prism having such characteristics can be manufactured by a known technique. The cross dichroic prism 121 synthesizes P-polarized green light and S-polarized green light and emits them from the projection lens 122.

In the present embodiment, the S-polarized green light and blue light undergo image modulation after undergoing two-time light modulation. In the system that illuminates the DMD display panel 113 and the DMD display panel 112, the light modulation is not performed twice. It is well known that this double light modulation leads to an increase in contrast. If the continuous light emission blue light is always radiated to the S-polarized green light and blue light system, the blue projection screen is very large due to the light modulation by the DMD display panel 111 and the DMD display panel 120 twice. A dynamic range is obtained, and an image in which blue light and green light are enlarged and projected in a time-division manner as in the present embodiment also obtains a large dynamic range.
It is assumed that the image of the system that does not perform the light modulation twice, that is, the system of the DMD display panel 112 for red and the DMD display panel 113 for green in this embodiment has an 8-bit gradation display. Further, it is assumed that at least 8-bit gradation display is ensured for the system that performs the light modulation twice (the illumination system of the DMD display panel 111 and the DMD display panel 120). At this time, the system that performs the light modulation twice may be 8 bits 256 gradations as a whole. That is, if the light modulation by the DMD display panel 111 of the first spatial light modulator and the DMD display panel 120 of the second spatial light modulator is performed with 4 bits and 16 gradations, the 256 floors are multiplied by multiplication. The key has been secured.

Consider the above gradation display from a temporal aspect. In the system that performs the light modulation twice, green light and blue light are alternately supplied. For example, the video frame rate is 60 Hz. The light supply time is half that of green light and blue light. This means that (16.7 ms / 2) ≈8.3 ms. The time of 8.3 ms is set to a time during which 256 gradation display is sufficiently possible. Here, switching between the two colors at a video frame rate of 60 Hz is at a level at which the color braking phenomenon can be recognized. This is because the level at which the color braking phenomenon cannot be recognized is said to be about 540 Hz at the video frame rate.
As described above, in the case of performing 256 gradations in total of the first light modulation and the second light modulation, it is necessary to perform 16 gradation modulation with each light modulation. Roughly speaking, 8.3 ms / 16≈0.52 ms is the time required for one gradation display. That is, when 256 gradation display is performed by double modulation, the display should be performed in a period of 0.52 ms. Considering that green and blue are alternately displayed, the frame rate is about 960 Hz. The video frame rate is increased from 60 Hz to 960 Hz. This means that the switching time between blue and green is similarly increased. 960 Hz is a high-speed one far exceeding the frame rate of 540 Hz, which is pointed out in the well-known technology and does not make the color braking phenomenon uncomfortable, eliminates the color braking phenomenon, and provides 8-bit gradation display quality. Also shows that it is satisfied at the same time.

By the way, the position where the DMD display panel 111 as the first spatial light modulator is disposed is optically equidistant from the DMD display panel 112 for red and the DMD display panel 113 for green as viewed from the light source unit 11. It is said that. The first spatial light modulator (DMD display panel 111) forms an image on the second spatial light modulator (DMD display panel 120) via the relay lens systems 114, 116, and 118. . If such a double modulation configuration is not used, only a relay lens system and one optical modulator are provided.
The three-plate type optical configuration of this embodiment is used to realize a compact optical system using a cross dichroic prism, as shown by the generalization of commercially available three-plate type liquid crystal projectors. The relay lens system has an essential configuration. In the present embodiment, the first spatial light modulator and the second spatial light modulator for performing double modulation are arranged at both ends of the relay lens system. Thus, the second spatial light modulator In addition to the above, no new optical system is added, and there is no significant difference from the optical system of a general three-plate liquid crystal projector that does not perform double modulation. This is because the structure of double modulation is adopted, and the color braking phenomenon, which is feared to occur in this system, can be eliminated by increasing the frame rate, that is, increasing the color switching speed. This indicates that a high-quality, small-sized projector can be provided without incurring adverse effects such as downsizing.

Note that the DMD display device used in the first spatial light modulator of the system that performs the dual modulation as in the present embodiment is compared with the resolution of the DMD display panel used in the second spatial light modulator. You can use a lower resolution. This is because it can be understood by considering the imaging relationship of the projection lens, but it is the DMD display panel for second modulation that is conjugate to the projection image and the optical system.
As a modification of the present embodiment, the display panel is changed to a liquid crystal panel or an LCOS panel instead of the DMD display panel, and the same effect as that of the present embodiment can be expected even with such a configuration. In addition, when using a liquid crystal panel, it is fundamental to use a TN type | mold liquid crystal panel.
Also, DMD display panels are used for the three display panels around the cross dichroic prism, LCOS panels are used for the display panel for the first modulation, and LCOS panels are used for the three display panels around the cross dichroic prism. However, it is also possible to use different types of display panels, such as using a DMD display panel for the first modulation display panel.

FIG. 2 is a block diagram showing the configuration of the optical system of the second embodiment of the projector according to the present invention. In this embodiment, a liquid crystal display panel is used as the display panel.
In the present embodiment, a red liquid crystal display panel 203 (third spatial light modulator) and a green liquid crystal panel 202 (fourth spatial light modulator) are provided in the red and green systems. A blue liquid crystal display panel 201 (first spatial light modulator) and a liquid crystal display panel 204 (second spatial light modulator) are provided for first modulation and second modulation.
In this embodiment, since the spatial light modulator is a liquid crystal display panel, polarizing plates are provided before and after the spatial light modulator, but in FIG. 2, the polarizing plates are omitted. Other components are the same as those of the first embodiment shown in FIG.
Regarding the polarization direction of the light transmitted or reflected through the cross dichroic prism 121, the red system and blue system of S-polarized light are reflected by the cross dichroic prism 121, and the green system of P-polarized light is transmitted through the cross dichroic prism 121. Since the cross dichroic prism 121 is designed, with respect to the polarizing plates arranged before and after the liquid crystal display panel, a retardation plate is added as necessary to adjust the polarization direction.

For example, S-polarized light is incident on the red liquid crystal display panel 203 from the light source unit 11. The polarization direction is rotated 90 degrees by the passage (modulation) of the liquid crystal display panel 203. Since the polarization direction of light incident on the cross dichroic prism 121 after exiting the liquid crystal display panel 203 needs to be S-polarized light, a retardation plate is combined with the polarizing plate used on the incident side of the liquid crystal display panel 203 for red. The P-polarized light is incident on the liquid crystal display panel 203 to perform modulation. The same applies to the green system and the blue system, and the polarizing plate and the phase difference plate are selected in consideration of the transmission and reflection design of the cross dichroic prism 121.
The operation of this embodiment is the same as that of the first embodiment, and the effect is also the same. The liquid crystal display panel 204 provided as a blue system is irradiated with blue light and green light in a time-sharing manner. The liquid crystal display panel 204 is driven at a frame rate that can eliminate the color breaking phenomenon, and an image corresponding to blue light and green light is switched. The modulation by the first modulation liquid crystal panel 201 and the second modulation liquid crystal panel 204 is multiplied to improve contrast, dynamic range, gradation, and the like.
In the case of a normal method that does not employ a double modulation configuration, increasing the frame rate leads to a reduction in the video display period of each color, so that sufficient gradation display is performed due to the response characteristics of the display device itself. I can't. In the present embodiment, the configuration in which double modulation is performed increases the dynamic range, maintains a gradation equivalent to 8 bits, and can eliminate the color braking phenomenon. Moreover, as described in the first embodiment, it is possible to realize a small-sized high-quality projector that does not cause a color braking phenomenon without changing the configuration and size of the optical system.

The light source unit 11 can be variously modified. In the first embodiment and the second embodiment, the LED is used as the light source. However, in addition to the LED light source, a laser light source can be additionally used. FIG. 5 is a block diagram showing a configuration of the light source unit 11 using a laser light source as an excitation light source of a phosphor emitting red or green.
5 includes a laser light source 501 that emits blue light, condenser lens systems 505, 506, 509, and 510, fluorescent wheels 503 and 504, dichroic mirrors 507 and 508, and an LED light source 502. A collimating lens 511, fly-eye lenses 512, 513, 515, 516, polarization conversion elements 507, 514, and a polarization beam splitter 518.
The laser light source 501 is for exciting a phosphor (not shown) provided on the fluorescent wheels 504 and 503 to obtain visible light. As the wavelength, blue light such as 520 nm can be used. The number to be used may be single or plural. As the number increases, excitation light with a large light output can be obtained, so that the fluorescence that can be acquired becomes larger.

The laser beam from the laser light source 501 is condensed by the condensing lens systems 505, 506, 509, 510 for condensing, and is condensed on the phosphors of the fluorescent wheels 503, 504, and fluorescence is generated there. Dichroic mirrors 507 and 508 are arranged in the optical path of the condenser lens systems 505, 506, 509 and 510. The dichroic mirror 508 has a characteristic of reflecting blue light and transmitting green light, and the dichroic mirror 507 has a characteristic of transmitting red light and reflecting blue light.
The fluorescent wheels 503 and 504 have a structure in which a phosphor is formed on a disk-shaped substrate and is rotatable. As the phosphor, a phosphor wheel 504 that emits fluorescence including green light with respect to blue excitation light and a phosphor wheel 503 that emits fluorescence including red light with respect to blue excitation light were used.
Such fluorescent substances that emit fluorescence have been commercialized and are available materials. The LED light source 502 emits blue light in the same manner as the LED light source 33 shown in FIG. Note that a blue laser light source can be used instead of the LED light source 502. The operations of the fly-eye lenses 512, 513, 515, and 516, the polarization conversion elements 507 and 514, and the polarization beam splitter 518 are the same as those shown in FIG.
The polarizing beam splitter 518 uses a composite of a dichroic mirror and a polarizing beam splitter as shown in FIG. Since the light source unit 11 shown in FIG. 5 obtains fluorescence by the excitation light of the laser light source 501, the amount of light from the light source unit 11 can be increased in accordance with the increase in output of the laser light source 501 being used. There is an effect that the output of the projector can be increased, that is, the brightness can be easily increased.

FIG. 4A is a block diagram showing a configuration of an optical system of a third embodiment of the projector according to the present invention.
In the present embodiment, the illumination lenses 101 and 107, the polarization beam splitter 103, the TIR prism 110, and the DMD display panel 113 are omitted from the first embodiment shown in FIG.
In the first embodiment shown in FIG. 1, a blue light image and a green light image that are doubly modulated by the DMD display panels 111 and 120, a red light image that is modulated by the DMD display panel 112, and the DMD display panel 113 are used. The modulated green light image is synthesized by the cross dichroic prism 121 and enlarged and projected by the projection lens 122. In the present embodiment, the blue light image and the green light that are doubly modulated by the DMD display panels 111 and 120 are used. Only the red light image modulated by the image and the DMD display panel 112 is synthesized by the cross dichroic prism 121 and enlarged and projected by the projection lens 122.
When this embodiment is compared with the first embodiment, there is no optical system for generating a green light image using the DMD display panel 113, and thus the size is reduced. Further, in the first embodiment, the light source unit 11 is configured to emit P-polarized green light reflected by the polarization beam splitter 103. In the present embodiment, It is not necessary to emit green P-polarized light, and a configuration for emitting P-polarized green light is not necessary, so that the configuration of the light source unit 11 can be simplified.
Since the configuration for eliminating the color braking phenomenon is the same as that of the first embodiment, description thereof is omitted. In the present embodiment, the color braking phenomenon is suppressed by the double modulation configuration, and the projector can be further downsized.

FIG. 4B is a block diagram showing the configuration of the optical system of the fourth embodiment of the projector according to the present invention.
In FIG. 4B, the light source unit 11, illumination lenses 102 and 106, reflection mirror 104, TIR prism 109, DMD display panel 112, and projection lens 122 are the same as those shown in FIG.
In this embodiment, blue and green light are emitted in time series in the illumination lenses 405 and 418, DMD display panels 411 and 420, TIR prisms 408 and 419 combined with the DMD display panels 411 and 420, and reflection. A lens 418 having a conjugate relationship between the mirror 415, the DMD display panel 411, and the DMD display panel 420 is provided.
In the present embodiment, the dichroic mirror 421 is used as an image combining element because the red image light to be combined and the blue and green image light are in an orthogonal relationship. Compared with the embodiment shown in FIG. 4, the present embodiment has a distance from the light source unit 11 to the DMD display panel 420 for forming blue image light, and the DMD display panel 420 for forming red image light. It is equal to the distance up to and is suitable for further miniaturization.

DESCRIPTION OF SYMBOLS 11 Light source part 101,102,105,106,107 Illumination lens 104 Reflection mirror 103 Polarization beam splitter 103
108, 109, 110, 119 TIR prism 111, 112, 113, 120 DMD display panel 114, 116, 118 Lens 115, 117 Reflection mirror 121 Cross dichroic prism 122 Projection lens

Claims (6)

An image combining element that includes a plurality of incident surfaces and an output surface, combines the image light respectively incident on the plurality of incident surfaces, and emits the light from the output surface;
First to third color lights of different colors are emitted, the first color light and the second color light are emitted in time series in a first direction, and the third color light is different from the first direction. A light source that emits in the direction of 2;
The first image light and the second color light are modulated between the first color light and the second color light that are provided between the first incident surface of the image composition element and the light source and are incident in time series. A first spatial light modulator and a second spatial light modulator that generate image light;
A third spatial light modulator that is provided between the second incident surface of the image composition element and the light source and modulates the incident third color light to generate third image light;
A lens system conjugate of the first spatial light modulator and the second spatial light modulator;
Projector. The projector according to claim 1, wherein
The light source emits fourth color light having the same color as the second color light in the first direction;
A beam splitter that reflects the fourth color light;
A fourth spatial light modulator that is provided between a third incident surface of the image composition element and the beam splitter, and modulates the fourth color light to generate fourth image light;
A projector further comprising: The projector according to claim 1 or 2,
The first spatial light modulator and the second spatial light modulator perform modulation with fewer gradations than other spatial light modulators, and the generated first image light and second image light are generated. A projector that modulates the tone so that the tone is equal to the tone of the other image light. The projector according to any one of claims 1 to 3,
A projector in which the spatial light modulator is a DMD display panel. The projector according to any one of claims 1 to 3,
A projector in which the spatial light modulator is a liquid crystal display panel. The projector according to any one of claims 1 to 3,
A projector whose spatial light modulator is LCOS.

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