JP2005114914A - projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector that can easily and reliably cope with an auxiliary light source incorporated in a projector without adding an optical element and a light source lamp is cut off.
When a projector 10 operates in an auxiliary light source mode, R ′ light emitted from an auxiliary light source 24a passes through a reflection mirror 23i and enters an opposing liquid crystal light valve 25a as illumination light. Illumination light, that is, image light modulated by the liquid crystal light valve 25 a enters the projection lens 29 via the cross dichroic prism 27. The color R ′ image light incident on the projection lens 29 is projected on a screen (not shown). That is, when the projector 10 operates in the normal mode, a color image is projected on the screen, but when the projector 10 operates in the auxiliary light source mode, a red single-color image is projected on the screen.
[Selection] Figure 1

Description

  The present invention relates to a projector that projects an image using a liquid crystal light valve or other light modulation device.

As a conventional projector, after separating the illumination light from the white light source into three colors RGB, the three liquid crystal light valves for each color are illuminated with the illumination light of each color, and the image light that has passed through each liquid crystal light valve is specially There is one that combines with a prism and projects such a composite image on a screen via a projection lens (see, for example, Patent Document 1).
JP 2001-92419 A

  In the projector as described above, a high-pressure mercury lamp, a halogen lamp, or the like is used as a white light source. However, these light source lamps are likely to be cut off due to a lifetime or an impact. Once the light source lamp is thus cut off, nothing is projected on the screen until the light source lamp is replaced, and information from the projector cannot be easily extracted.

  Here, it is conceivable that a replacement auxiliary lamp is built in the projector in advance, and the auxiliary lamp is turned on as soon as the light source lamp is cut off. However, the illumination light from the auxiliary lamp is guided to the regular optical path. An optical element or mechanism is required, resulting in an increase in cost and an increase in the size of the projector. In addition, the optical element causes a light loss. Furthermore, there is no guarantee how long the switched auxiliary lamp will continue to operate.

  In addition, when the projector is realized as a digital broadcasting TV or the like, there is an operation in an audio mode for receiving a normal radio broadcast. In this case, additional information such as the current channel and operation state is displayed with low power. It is desirable to be able to do it.

  Furthermore, although a projector using a light source lamp such as a high-pressure mercury lamp has a sufficiently high brightness, it takes a long time until it can be displayed with a stable and sufficient brightness since its startup is slow after startup.

  Therefore, an object of the present invention is to provide a projector that can easily and reliably cope with a case where an auxiliary light source is incorporated in a projector without adding an optical element and a light source lamp is cut off.

  It is another object of the present invention to provide a projector that can easily perform a display operation with low power in an audio mode or the like.

  Another object of the present invention is to provide a projector that can perform a temporary display even at the time of starting until the light source lamp operates stably with sufficient brightness immediately after startup.

  In order to solve the above problems, a projector according to the present invention includes (a) a first light source device that generates light source light, and (b) light splitting optics that divides the light source light from the first light source device into illumination light of each color. A system, (c) a plurality of light modulation devices for each color illuminated by illumination light of each color emitted from the light splitting optical system, and (d) combining image light of each color from the plurality of light modulation devices A light combining optical system to be emitted; (e) a projection optical system that projects image light combined through the light combining optical system; (f) a second light source device that generates auxiliary light; and (g) a second light source device. Auxiliary light introducing means for introducing the auxiliary light into the optical path of the light splitting optical system. The light modulation device is a concept including various light modulation display elements such as a liquid crystal light valve and a digital mirror device (DMD).

  Since the projector includes the second light source device that generates auxiliary light, in the audio mode or the like, the first light source device that is the main light source is intentionally switched to the second light source device that is the auxiliary light source. Simple display can be performed. Alternatively, when the first light source device is in a state of insufficient brightness immediately after startup, or when the first light source device is unexpectedly cut off due to breakage, life, or the like, the second light source device, which is an auxiliary light source, is temporarily turned on to temporarily or urgently Display can be performed. Here, since the auxiliary light introducing means introduces auxiliary light from the second light source device onto the optical path of the light splitting optical system, an optical element, a mechanical mechanism, or the like for guiding the auxiliary light from the second light source device to the regular optical path is provided. Compared to the case where it is provided between the first light source device and the light splitting optical system, that is, compared to the case where the spare lamp is arranged at the equivalent position of the main light source, the shape of the projector is increased and the size of the projector is reduced. Can be

  In a specific aspect of the present invention, the auxiliary light introducing unit also serves as an optical element such as a mirror or a prism for processing the illumination light in the light splitting optical system. In this case, without adding a special optical element, the normal light splitting optical system can be used as it is or only by additionally changing the function of an optical element such as a mirror constituting the auxiliary optical system. Light can be easily introduced onto the optical path of the light splitting optical system. Therefore, it is almost unnecessary to change the existing optical system, and an increase in the cost and size of the projector can be easily prevented.

  In another specific aspect of the present invention, the light splitting optical system includes a polarization separation type deflection mirror as an optical element, and the polarization mirror transmits reflected reflected light via the back surface of the deflection mirror. When auxiliary light is incident substantially parallel to the direction, it operates as auxiliary light introducing means. In this case, the auxiliary light from the second light source device is introduced onto the optical path of the light splitting optical system only by slightly modifying a part of the function without changing the element configuration of the normal light splitting optical system. Therefore, the change of the existing optical system can be minimized.

  In yet another specific aspect of the present invention, the illumination light is polarized in a predetermined direction before entering the deflection mirror, and the auxiliary light is polarized in a direction orthogonal to the predetermined direction before entering the deflection mirror. . In this case, loss of illumination light and auxiliary light in the deflection mirror can be prevented, and efficient illumination becomes possible.

  According to still another specific aspect of the present invention, an image processing device for operating a plurality of light modulation devices is further provided, and when the image processing device operates the first light source device, a plurality of light beams are provided. The modulation device is operated in one of the normally-on and normally-off modulation states, and when the second light source device is operated, the light modulation device is operated in the other modulation state of normally-on and normally-off. When a polarization separation type deflection mirror is used, the polarization direction of the illumination light incident on the light modulation device and the polarization direction of the auxiliary light are orthogonal to each other. In this case, the modulation state related to transmittance and reflectance is inverted in advance to prevent display inversion.

  In still another specific aspect of the present invention, the light splitting optical system includes a plurality of dichroic mirrors, and at least one dichroic mirror among the plurality of dichroic mirrors transmits and emits the at least one dichroic mirror. When auxiliary light is incident through the surface substantially parallel to the direction of reflected emission light, it operates as auxiliary light introducing means. In this case, the auxiliary light from the second light source device is introduced onto the optical path of the light splitting optical system only by slightly modifying a part of the function without changing the element configuration of the normal light splitting optical system. Therefore, the change of the existing optical system can be minimized.

  In yet another specific aspect of the present invention, the illumination light is polarized in a predetermined direction before entering the at least one dichroic mirror, and the auxiliary light is orthogonal to the predetermined direction before entering the at least one dichroic mirror. The direction of polarization. In this case, loss of illumination light and auxiliary light in the dichroic mirror can be prevented, and efficient illumination becomes possible.

  In still another specific aspect of the present invention, the light splitting optical system splits the light source light into RGB three-color illumination light, and the second light source device has at least one of RGB corresponding to the illumination light. The color auxiliary light is emitted, and the auxiliary light introducing means guides at least one color auxiliary light from the second light source device to the corresponding color light modulation device. In this case, the second light source device, which is an auxiliary light source, can be used to illuminate the light modulation device with a color corresponding to a normal operation, so that simple auxiliary illumination can be achieved without changing the basic structure of the projector. can do. The second light source device individually emits auxiliary light of each color of RGB corresponding to the illumination light, and the auxiliary light introducing unit supplies the auxiliary light of each color from the second light source device to the corresponding light modulator. When each is guided, color display is possible even when the second light source device, that is, the auxiliary light source is operated.

  In yet another specific aspect of the present invention, the auxiliary light illuminates partial areas of a plurality of light modulation devices. In this case, a simple display can be performed with power saving by using a part of the normal display area.

  In still another specific aspect of the present invention, the image processing device further includes an image processing device for operating a plurality of light modulation devices, and the image processing device operates the second light source device to emit auxiliary light. Sometimes, a plurality of light modulation devices are operated in a mode different from the normal mode. In this case, an appropriate display different from the normal image can be performed in correspondence with the operation of the second light source device, that is, the auxiliary light source. Specifically, even when the first light source device fails, control information from the projector can be easily retrieved and displayed, and additional information such as channels and operating states is displayed in operations such as audio mode without image display. it can.

  In yet another specific aspect of the present invention, the second light source device includes at least one solid-state light source. In this case, the second light source device, that is, the auxiliary light source, can be made small in size and have low power consumption, and such an auxiliary light source can be incorporated into the projector apparatus with a simple design change.

[First Embodiment]
The structure of the projector according to the first embodiment of the invention will be described below with reference to the drawings.

  FIG. 1 is a diagram for explaining an optical system of a projection apparatus, that is, a projector according to an embodiment. The projector 10 includes a first light source device 21 that generates light source light, a light splitting optical system 23 that divides the light source light from the first light source device 21 into three colors of RGB, and generates auxiliary light and auxiliary light. The second light source device 24 supplied to the light splitting optical system 23, the light modulation unit 25 normally illuminated by the illumination light of each color from the light splitting optical system 23, and the image light of each color from the light modulation unit 25 are combined. And a projection lens 29 for projecting the image light combined by the cross dichroic prism 27 onto a screen (not shown). Further, the projector 10 includes an image processing unit 40 that performs an appropriate process on an image signal input from the outside, and liquid crystal light valves for each color (described later) incorporated in the light modulation unit 25 according to the output of the image processing unit 40. The driving circuit 42 for outputting a driving signal and the above-described first light source device 21, second light source device 24, image processing unit 40, etc. are appropriately operated to control the overall operation of the device. And a control device 50 for controlling. Here, the control device 50, the image processing unit 40, and the like constitute an image processing device for operating the light modulation unit 25 as appropriate.

  The first light source device 21 includes a light source lamp 21a, a pair of fly's eyes 21b and 21c, a polarization conversion member 21d, a superimposing lens 21e, and a main light source driving circuit 31. Here, the light source lamp 21a is a main light source composed of, for example, a high-pressure mercury lamp or a halogen lamp, and includes a concave mirror for collimating the light source light, operates by receiving power supplied from the main light source driving circuit 31, Turns on or off at an appropriate timing. Further, the pair of fly eyes 21b and 21c divides the light source light from the light source lamp 21a by a plurality of element lenses arranged in a matrix and individually collects and diverges the light, and the superimposing lens 21e includes the fly eye 21b. , 21c are appropriately converged, and are uniformly superimposed on the liquid crystal light valves of the respective colors provided in the light modulator 25 and described in detail later. The polarization conversion member 21d sandwiched between the fly-eye 21b, 21c and the superimposing lens 21e converts the light source light emitted from the fly-eye 21c into, for example, only the S-polarized component perpendicular to the paper surface of FIG. Supply to stage optical system.

  The light splitting optical system 23 includes first and second dichroic mirrors 23a and 23b, a λ / 2 plate 23d, three field lenses 23f to 23h, and reflection mirrors 23i to 23k. In addition, the incident side polarization filters 91 a to 93 a also constitute a part of the light splitting optical system 23. Of these, the first dichroic mirror 23a reflects R light and transmits G light and B light among the three colors of incident RGB. The second dichroic mirror 23b reflects G light and transmits B light out of the two colors of incident GB. In this light splitting optical system 23, the R light incident on and reflected by the first dichroic mirror 23a is incident on the field lens 23f via the incident side polarization filter 91a and the reflection mirror 23i while remaining as S-polarized light. Further, the G light that has passed through the first dichroic mirror 23a and reflected by the second dichroic mirror 23b is converted from S-polarized light to P-polarized light by the λ / 2 plate 23d, passes through the field lens 23g, and enters the incident-side polarizing filter 92a. Incident. Further, the B light that has passed through the second dichroic mirror 23b remains as S-polarized light and enters the incident-side polarizing filter 93a via the relay lenses LL1 and LL2, the reflecting mirrors 23j and 23k, and the field lens 23h.

  The second light source device 24 corresponds to the color R generated by the first light source device 21, but an auxiliary light source 24a that generates auxiliary light of a slightly different color R ′, and an auxiliary for operating the auxiliary light source 24a in an appropriate state. A light source driving circuit 24s. Here, the auxiliary light source 24a includes an LED 24e that is a solid light source, a concave reflecting mirror 24h, a condenser lens 24i, and a polarizing filter 95a. The auxiliary light of color R ′ emitted from the auxiliary light source 24a is guided onto the optical path of the R light in the light splitting optical system 23 via the reflection mirror 23i which is a polarization separation type deflection mirror. The mirror 23 i is a component of the light splitting optical system 23 and also serves as auxiliary light introducing means for introducing auxiliary light onto the optical path of the light splitting optical system 23.

  A specific operation will be described. The R ′ light from the LED 24e provided in the auxiliary light source 24a is converted into P-polarized light by the polarizing filter 95a, and is substantially parallel to the emission direction of the R light that is regular reflected emission light in the reflection mirror 23i. In this state, the light enters the back surface RS side of the reflection mirror 23i. Here, the reflection mirror 23i is obtained by forming a dielectric multilayer film on the surface FS side of a flat plate. Since this dielectric multilayer film has the property of reflecting S-polarized light but transmitting P-polarized light, the R ′ light incident on the reflecting mirror 23 i is transmitted through the reflecting mirror 23 i as P-polarized light and reflected. The light travels substantially parallel to the direction of the R light as S-polarized light reflected by the surface FS of the mirror 23i and is coupled to the optical path of the R light.

  The light modulation unit 25 includes three liquid crystal light valves 25a to 25c and three exit side polarization filters 91b to 93b arranged on the exit side of the liquid crystal light valves 25a to 25c. When the light source lamp 21a of the first light source device 21 is turned on, the R light, which is normal illumination light reflected by the first dichroic mirror 23a, is a field lens 23f for adjusting the incident angle with respect to the irradiated surface. Through the liquid crystal light valve 25a. Further, the G light, which is normal illumination light that is transmitted through the first dichroic mirror 23a and reflected by the second dichroic mirror 23b, passes through the field lens 23g and the incident-side polarization filter 92a for adjusting the incident angle. The light enters the liquid crystal light valve 25b. B light, which is normal illumination light that has passed through the first and second dichroic mirrors 23a and 23b, enters the liquid crystal light valve 25c via the field lens 23h and the incident-side polarizing filter 93a. Each of the liquid crystal light valves 25a to 25c is a spatial light modulator for modulating the spatial intensity distribution of the incident illumination light, and the three colors of light incident on the liquid crystal light valves 25a to 25c are respectively Modulated according to the input image. At that time, the polarization direction of the illumination light incident on the liquid crystal light valves 25a to 25c is accurately adjusted by the incident side polarizing filters 91a to 93a arranged in front of the liquid crystal light valves 25a to 25c. Further, by the exit side polarization filters 91b to 93b arranged immediately after the liquid crystal light valves 25a to 25c, a predetermined polarization direction (respective liquid crystal light valves 25a to 25c) is obtained from the modulated light emitted from the liquid crystal light valves 25a to 25c. Is operated in a normally-on mode, for example, modulated light of only P-polarized light for R light and B light and S-polarized light for G light is extracted.

  In the case where the first light source device 21 breaks down and its operation is stopped, the first light source device 21 has insufficient brightness immediately after startup, or the first light source device 21 is forcibly put into a dormant state. When the auxiliary light source 24a provided in the two-light source device 24 is operated, the R ′ light that is auxiliary light output from the auxiliary light source 24a is introduced into the optical path of the R light via the back surface RS of the reflecting mirror 23i. Like the R light, it enters the liquid crystal light valve 25a through the field lens 23f. In other words, when the second light source device 24 is operated, the liquid crystal light valve 25a is illuminated with the R ′ light different from the normal light, and the auxiliary light of the R ′ light can be modulated. At this time, since the P-polarized illumination light is incident on the liquid crystal light valve 25a and the P-polarized image light is extracted, the liquid crystal light valve 25a performs an operation different from the modulation state in the normal mode in which the first light source device 21 is operated. There is a need. For example, when the liquid crystal light valve 25a is operated in the normally-on state in the normal mode, it is necessary to operate the liquid crystal light valve 25a in the normally-off state in the auxiliary light source mode. Conversely, the liquid crystal light valve 25a is normally operated in the normal mode. When operating in the normally off state, it is necessary to operate the liquid crystal light valve 25a in the normally on state in the auxiliary light source mode. In the former case, when operating in the normal mode, white with high transmittance is expressed without voltage application. Therefore, the auxiliary light source mode in which the second light source device 24 is operated instead of the first light source device 21. Then, by reversing the pixel signal, that is, the signal applied to the liquid crystal light valve 25a and operating in the normally-off state, it is possible to prevent black and white inversion of the display for the input image signal as a result. Specifically, by changing the operation of the image processing unit 40, the pixel signal output to the drive circuit 42 and then to the liquid crystal light valve 25a is inverted in advance to ensure normal display in the auxiliary light source mode. Can do.

  The cross dichroic prism 27 is a light-synthesizing optical system, and incorporates a dielectric multilayer film 27a for reflecting R light and a dielectric multilayer film 27b for reflecting B light in a state of being orthogonal to each other. The R light or R ′ light from the light valve 25a is reflected by the dielectric multilayer film 27a and emitted to the right in the traveling direction, and the G light from the second liquid crystal light valve 25b travels straight through the dielectric multilayer film 27b. The B light from the third liquid crystal light valve 25c is reflected by the dielectric multilayer film 27b and emitted to the left in the traveling direction. Thus, the synthesized light synthesized by the cross dichroic prism 27 enters a projection lens 29 that is a projection optical system.

  The image processing unit 40 outputs drive signals to the liquid crystal light valves 25 a to 25 c provided in the light modulation unit 25 via the drive circuit 42. A digital image signal from a personal computer and a video image signal from a video reproduction device or the like are selectively input to the image processing unit 40 via a switching device 61. Further, the image processing unit 40 is input with image data related to control information related to the operation status of the projector 10 from the control device 50.

  The control device 50 outputs a control signal to the auxiliary light source driving circuit 24s and the main light source driving circuit 31, and causes the light source lamp 21a provided in the first light source device 21 to emit light at an appropriate timing to emit R light, or The auxiliary light source 24a provided in the second light source device 24 emits light at an appropriate timing to emit R ′ light. Further, the control device 50 outputs a control signal to the drive circuit 42 via the image processing unit 40, and causes each of the liquid crystal light valves 25a to 25c to form a two-dimensional polarization characteristic distribution corresponding to the brightness of the projected image. . The control device 50 includes a light source sensor 62, and can detect malfunctions such as breakage of the light source lamp 21a and insufficient brightness. For example, when the light source sensor 62 detects a malfunction of the light source lamp 21a, the control device 50 stops the power supply to the main light source drive circuit 31 and starts the power supply to the auxiliary light source drive circuit 24s, so that the first light source The operation state of the device 21 (normal mode) is switched to the operation state of the second light source device 24 (auxiliary light source mode). Further, when the projector 10 is realized as a digital broadcast TV or the like, the auxiliary information such as the current channel and the operation state is displayed on the screen with low power when operating in the audio mode for receiving the normal radio broadcast. At this time, the operation of the projector 10 is switched from the normal mode similar to the above to the auxiliary light source mode, and the control device 50 operates only the liquid crystal light valve 25a to display an image by R ′ light. In the auxiliary light source mode as described above, the image data necessary for display by the R ′ light is appropriately prepared by the control device 50. Specifically, a warning that damages the currently used light source lamp 21a and a prompt to replace with a new light source lamp 21a, a display that informs normal operation in the audio mode, a radio channel display in the audio mode, Immediately after startup, image data such as a display indicating that the lamp brightness is not sufficient but is operating normally or in a standby state is read from a memory provided in the control device 50. In addition, when displaying that the lamp is not bright enough but is in a normal operating state immediately after startup, any one of the first light source devices 21 is provided with a mechanical shutter to turn on the light source lamp 21a. However, the illumination light that becomes noise is prevented from entering the light splitting optical system 23.

  Hereinafter, the operation of the projector 10 of FIG. 1 will be described. The light source light from the first light source device 21 is color-divided by the first and second dichroic mirrors 23a and 23b provided in the light splitting optical system 23, and is incident on the corresponding liquid crystal light valves 25a to 25c as illumination lights of the respective colors. To do. Each of the liquid crystal light valves 25a to 25c is modulated by an image signal from the outside and has a two-dimensional refractive index distribution, and modulates illumination light in a two-dimensional space in units of pixels. As described above, the illumination light, that is, the image light modulated by the liquid crystal light valves 25 a to 25 c is combined by the cross dichroic prism 27 and enters the projection lens 29. The image light incident on the projection lens 29 is projected as a color image on a screen (not shown). The above is the description of the operation in the normal mode. However, in the auxiliary light source mode in which the first light source device 21 breaks down and the operation stops, or the first light source device 21 is in the dormant state, the second light source device The auxiliary light source 24a provided at 24 is turned on. In this case, the R ′ light emitted from the auxiliary light source 24a passes through the reflection mirror 23i and enters the opposing liquid crystal light valve 25a as auxiliary illumination light. The liquid crystal light valve 25a operates independently to modulate auxiliary illumination light in a two-dimensional space in units of pixels. As described above, the auxiliary light, that is, the image light modulated by the liquid crystal light valve 25 a enters the projection lens 29 through the cross dichroic prism 27. The color R ′ image light incident on the projection lens 29 is projected onto a screen (not shown). That is, when the projector 10 operates in the normal mode, a color image is projected on the screen. However, when the projector 10 operates in the auxiliary light source mode, a red single-color image is projected on the screen. The image projected on the screen in the auxiliary light source mode corresponds to the auxiliary light source mode, such as a warning of damage to the light source lamp 21a and a lighting preparation state at the start.

  In the above description, the auxiliary light source 24a is used to illuminate the entire surface of the liquid crystal light valve 25a. However, the R ′ light from the auxiliary light source 24a is either at the center or the four corners of the illuminated area of the liquid crystal light valve 25a. In addition, the light can be incident on a partial region such as an upper part or a lower part. In this case, since the entire liquid crystal light valve 25a is not illuminated, the brightness of display on the screen can be sufficiently increased even when the output of the LED 24e is low.

[Second Embodiment]
FIG. 2 is a diagram illustrating the projector according to the second embodiment. The projector according to the second embodiment is a modification of the projector according to the first embodiment, and the same portions are denoted by the same reference numerals and redundant description is omitted.

  The projector 110 according to the present embodiment includes, as the second light source device 124, an auxiliary light source 24c for B 'light in addition to the auxiliary light source 24a for R' light. The auxiliary light source 24c includes an LED 24g, a concave reflecting mirror 24h, a condenser lens 24i, and a polarizing filter 95c. Here, the LED 24g is driven by the auxiliary light source driving circuit 24s and emits auxiliary light of a color B 'corresponding to the color B generated by the first light source device 21 but slightly different at an appropriate timing.

  On the other hand, the reflection mirror 123k provided in the light splitting optical system 23 is a polarization separation type deflection mirror that also operates as auxiliary light introducing means. That is, the auxiliary light of the color B ′ emitted from the auxiliary light source 24c is guided onto the optical path of the B light in the light splitting optical system 23 through the reflection mirror 123k. More specifically, the B ′ light from the LED 24g is converted into P-polarized light by the polarizing filter 95c, and enters the reflection mirror 23i in a state substantially parallel to the emission direction of the B light that is normal reflected emission light at the reflection mirror 23i. Incident from the back side. Thus, the B ′ light incident on the reflection mirror 23i passes through the reflection mirror 23i while being P-polarized light, and travels substantially parallel to the emission direction of the B light as S-polarized light reflected on the surface side of the reflection mirror 23i. Then, it is coupled to the optical path of B light, which is normal illumination light.

  In this case, the B ′ light emitted from the auxiliary light source 24c passes through the reflection mirror 123k and enters the opposing liquid crystal light valve 25c as auxiliary illumination light. The liquid crystal light valve 25c modulates auxiliary illumination light of B 'color in a two-dimensional space in units of pixels. In the auxiliary light source mode in which the auxiliary light source 24c is turned on, the B ′ color modulation is an inversion of the normal modulation mode. However, the display luminance can be obtained simply by turning on / off the signal output from the drive circuit 42. Can be avoided. On the other hand, the R ′ light emitted from the other auxiliary light source 24a enters the liquid crystal light valve 25a through the reflection mirror 23i, and is modulated two-dimensionally in pixel units. That is, when the projector 10 operates in the auxiliary light source mode, a two-color image of red and blue is projected on the screen.

[Third Embodiment]
FIG. 3 is a diagram illustrating the projector according to the third embodiment. The projector according to the third embodiment is a further modification of the projector according to the second embodiment.

  The projector 210 according to this embodiment includes, as the second light source device 224, an auxiliary light source 24b for G 'light in addition to the auxiliary light source 24a for R' light and the auxiliary light source 24c for B 'light. The auxiliary light source 24b includes an LED 24f, a concave reflecting mirror 24h, a condenser lens 24i, and a polarizing filter 95b. Here, the LED 24 f is driven by the auxiliary light source driving circuit 24 s to emit auxiliary light of a color G ′ corresponding to the color G generated by the first light source device 21 but at a slightly different timing.

  On the other hand, the second dichroic mirror 123b provided in the light splitting optical system 23 is a polarization separation type dichroic mirror that also operates as auxiliary light introducing means. That is, the auxiliary light of color G ′ emitted from the auxiliary light source 24b is guided onto the optical path of the light splitting optical system 23 via the second dichroic mirror 123b. More specifically, the G ′ light from the LED 24f is converted to P-polarized light by the polarization filter 95b, and is substantially parallel to the emission direction of the G light that is reflected and branched light by the second dichroic mirror 123b. It is incident on 123b from the back side. Thus, the G ′ light that has entered the second dichroic mirror 123b passes through the second dichroic mirror 123b while remaining P-polarized light, and is emitted as B-polarized light as S-polarized light that is reflected on the surface side of the second dichroic mirror 123b. The light travels substantially parallel to the direction and is coupled to the optical path of G light, which is normal illumination light.

  In this case, the G ′ light emitted from the auxiliary light source 24b passes through the second dichroic mirror 123b, is converted from P-polarized light to S-polarized light by the λ / 2 plate 23d, and then assists the opposing liquid crystal light valve 25b as auxiliary illumination. Incident as light. The liquid crystal light valve 25b modulates auxiliary illumination light of G 'color in a two-dimensional space in units of pixels. In the auxiliary light source mode in which the auxiliary light source 24b is turned on, the G ′ color modulation is obtained by inverting the normal modulation mode. However, the display brightness can be obtained by simply turning on / off the signal output from the drive circuit 42. Can be avoided. On the other hand, the R ′ light and B ′ light emitted from the other pair of auxiliary light sources 24a and 24c are incident on the liquid crystal light valves 25a and 25c through the reflecting mirrors 23i and 123k, respectively, and are here two-dimensionally spatially in pixel units. Modulated with. That is, when the projector 10 operates in the auxiliary light source mode, a color image composed of red, blue, and green is projected on the screen.

  FIG. 4 is a graph conceptually illustrating the transmission / reflection characteristics of the second dichroic mirror 123b. As is apparent from the graph, the S-polarized G color is reflected by the second dichroic mirror 123b shown in FIG. 3 and illuminates the G light liquid crystal light valve 25b, while the P-polarized G color is The liquid crystal light valve 25b for G light is illuminated through the second dichroic mirror 123b. That is, the wavelength range of G ′ light emitted from the auxiliary light source 24b is set between the edge wavelengths of S-polarized light and P-polarized light.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments. For example, in the projector 10 of the first embodiment, red is displayed by R ′ light in the auxiliary light source mode, but the auxiliary light source 24a for R ′ light is excluded in the projector 110 of the second embodiment. For example, in the auxiliary light source mode, blue display with B ′ light can be performed.

  In the projector 210 of the third embodiment, the auxiliary G ′ light is split by the light splitting optical system 23 via the second dichroic mirror 123b that is an optical element of the light splitting optical system 23. For the optical path bending in which the G light split by the light splitting optical system 23 is an optical element of the light splitting optical system 23, but is introduced into the optical path of the second dichroic mirror 123b. When the optical arrangement is such that the light enters the liquid crystal light valve 25b for G light via the reflection mirror (that is, when there is a reflection mirror for beam bending for G light), such a reflection mirror is used. G ′ light can be guided to the optical path of the divided G light.

  In the projector 210 of the third embodiment, auxiliary light such as R ′ light, B ′ light, or G ′ light is introduced through the reflecting mirrors 23 i and 123 k and the second dichroic mirror 123 b. It is also possible to illuminate the liquid crystal light valves 25a to 25c by introducing R ′ light, B ′ light, or G ′ light from an oblique direction on the optical path of the R light, B light, or G light. Although the efficiency is reduced, it is not necessary to configure the reflection mirrors 23i and 123k and the second dichroic mirror 123b with a polarization separation type multilayer film.

  In the projector 210 of the third embodiment, in the auxiliary light source mode, the light source lamp 21a is warned of breakage, the channel corresponding to radio broadcast reception is displayed, and the like. However, when the second light source device 224 is operated. In the same manner as in the normal mode, a color image input as a video signal or the like can be projected.

It is a figure which shows the structure of the projector which concerns on 1st Embodiment. It is a figure which shows the structure of the projector which concerns on 2nd Embodiment. It is a figure which shows the structure of the projector which concerns on 3rd Embodiment. It is a graph which shows the characteristic of a 2nd dichroic mirror.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector, 21 ... 1st light source device, 21a ... Light source lamp, 23 ... Light splitting optical system, 23a ... 1st dichroic mirror, 23b ... 2nd dichroic mirror, 23i-23k ... Reflection mirror, 24 2nd light source device, 24a ... auxiliary light source, 24s ... auxiliary light source drive circuit, 25 ... light modulation unit, 25a-25c ... liquid crystal light valve, 27 ... cross dichroic prism, 29 ... projection lens, 31 ... main light source drive circuit, 40 ... image processing unit, 50 ... Control device, 91a to 93a ... Incident side polarization filter, 91b to 93b ... Emission side polarization filter, 95a to 95c ... Polarization filter

Claims (11)

A first light source device for generating light source light;
A light splitting optical system that splits light source light from the first light source device into illumination light of each color;
A plurality of light modulators for each color illuminated by illumination light of each color emitted from the light splitting optical system;
A light combining optical system for combining and emitting image light of each color from the plurality of light modulation devices;
A projection optical system for projecting the image light combined through the light combining optical system;
A second light source device for generating auxiliary light;
A projector comprising: auxiliary light introducing means for introducing the auxiliary light from the second light source device onto an optical path of the light splitting optical system.   The projector according to claim 1, wherein the auxiliary light introducing unit also serves as an optical element for processing illumination light in the light splitting optical system.   The light splitting optical system includes a polarization separation type deflecting mirror as the optical element, and the polarizing mirror causes the auxiliary light to be incident substantially parallel to the direction of reflected emission light through the back surface of the deflecting mirror. 3. The projector according to claim 2, wherein the projector operates as the auxiliary light introducing means.   4. The polarized light in a predetermined direction before the illumination light is incident on the deflection mirror, and the polarized light in a direction orthogonal to the predetermined direction before the auxiliary light is incident on the deflection mirror. Projector.   The image processing apparatus further includes an image processing device for operating the plurality of light modulation devices, and the image processing device modulates the plurality of light modulation devices to one of normally-on and normally-off when operating the first light source device. 5. The projector according to claim 4, wherein the light modulation device is operated in the other modulation state of normally-on and normally-off when the second light source device is operated.   The light splitting optical system includes a plurality of dichroic mirrors, and at least one dichroic mirror among the plurality of dichroic mirrors is substantially parallel to the direction of reflected and emitted light through a transmission exit surface of the at least one dichroic mirror. 3. The projector according to claim 2, wherein the projector operates as the auxiliary light introducing means when the auxiliary light is incident on the projector.   The illumination light is polarized in a predetermined direction before being incident on the at least one dichroic mirror, and the auxiliary light is polarized in a direction orthogonal to the predetermined direction before being incident on the at least one dichroic mirror. The projector according to claim 6.   The light splitting optical system splits the light source light into RGB three-color illumination light, and the second light source device emits auxiliary light of at least one of RGB corresponding to the illumination light, and the auxiliary light The projector according to claim 1, wherein the light introducing unit guides the at least one color auxiliary light from the second light source device to the light modulation device of a corresponding color.   The projector according to claim 1, wherein the auxiliary light illuminates a partial region of the plurality of light modulation devices.   The image processing device further includes an image processing device for operating the plurality of light modulation devices, and the image processing device normally sets the plurality of light modulation devices when the second light source device operates to emit the auxiliary light. The projector according to claim 1, wherein the projector is operated in a mode different from the first mode. The projector according to claim 1, wherein the second light source device includes at least one solid-state light source.

Images