JP2016170436A - Projector and control method for projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector which can appropriately control a light source or a light modulation element by detecting the light quantity highly related to the light contributing to the image display.SOLUTION: A projector 1 according to the present invention includes an illumination device 2, a polarization separation element that separates the light emitted from the illumination device 2 into first polarized light and second polarized light whose polarization directions are orthogonal to each other, reflective liquid crystal panels 4R, 4G, and 4B that modulate the polarized state of one of the first polarized and the second polarized light, a light sensor 36 that detects the light quantity of the other polarized light, a control unit that controls at least one of the illumination device 2 and the reflective liquid crystal panels 4R, 4G, and 4B on the basis of the result of detecting the light quantity, and a first diaphragm 37 and a second diaphragm 38 that transmit the polarized light, which enters a light detection surface of the light sensor 36 at a small incidence angle, at higher transmission than the polarized light that enters the light detection surface at a relatively large incidence angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projector.

  In a projector, a technique has been proposed in which the amount of light emitted from a light source is detected, and the light source or the display panel is controlled according to the detection result to correct a color change due to a temporal change of the light source (for example, a patent). Reference 1). This document describes that irregularly reflected light from a lens array for making illumination light uniform is detected by an optical sensor, and a lamp and a liquid crystal panel are controlled according to the output of the optical sensor. However, when a reflective liquid crystal panel is applied to a projector that performs this type of control, some of the reflected light from the liquid crystal panel returns to the light source depending on the display content, so the detection result of the optical sensor varies depending on the display content. However, accurate detection results may not be obtained. As a result, there has been a problem that the lamp and the liquid crystal panel cannot be appropriately controlled.

  In view of this, a technique has been proposed in which an image display device having a reflective light modulation element detects the amount of light irradiated to the light modulation element with high accuracy by detecting the intensity of light that is not used in the display image. (For example, refer to Patent Document 2). This image display device includes a polarization beam splitter between a light source and a digital micromirror device (DMD), and uses P-polarized light that passes through the polarization beam splitter for image display, but does not contribute to image display. S-polarized light reflected by the beam splitter is detected by an optical sensor.

JP-A-11-65528 Republished WO2007 / 023681

  However, the image display device described in Patent Document 2 also has a problem that the amount of light detected by the optical sensor does not sufficiently reflect the amount of light that actually contributes to image display. Therefore, there still remains a problem that the light source and the light modulation element cannot be appropriately controlled.

  The present invention has been made to solve the above-described problems, and provides a projector capable of appropriately controlling a light source and a light modulation element by detecting a light amount highly correlated with light contributing to image display. Objective.

  In order to achieve the above object, a projector according to an aspect of the invention includes a light source, and a polarization separation element that separates light emitted from the light source into a first polarization and a second polarization whose polarization directions are orthogonal to each other. , One of the first polarized light and the second polarized light is incident, the polarization state of the incident polarized light is modulated based on an image signal, and the modulated polarized light is directed to the polarization separation element Based on the detection result of the light detection element, the light detection element for detecting the light quantity of the other polarization of the first polarization and the second polarization, A control unit that controls at least one of a light source and the light modulation element; a first incident angle limiting member provided between the light source and the polarization separation element; the polarization separation element and the light detection element; A second incident angle limiting member provided between, The first incident angle limiting member and the second incident angle limiting member are incident at a relatively small incident angle with respect to the light detection surface of the light detection element. The transmitted light is transmitted with a higher transmittance than light incident at a relatively large incident angle with respect to the light detection surface.

  In the projector according to the aspect of the invention, the light detecting element detects the other polarized light of the first polarized light and the second polarized light, that is, the light quantity of the polarized light not incident on the light modulating element, and the control unit detects the light. Based on the detection result of the detection element, at least one of the light source and the light modulation element is controlled. Therefore, the light detection element can be arranged at a position out of the optical path of the polarized light that contributes to the image, so that accurate light amount detection is performed regardless of the display content without being affected by the return light from the reflection type light modulation element. be able to.

  In addition, various stray light exists in the optical path of the projector, and stray light becomes a factor that reduces the detection accuracy of the light amount. The stray light is, for example, light reflected and scattered by various optical components and the like, and generally has a large angle with respect to the optical axis of the optical component. Here, the projector according to the present invention transmits polarized light incident at a relatively small incident angle with respect to the light detection surface of the light detecting element with a higher transmittance than polarized light incident at a relatively large incident angle. Since the angle limiting member is provided, the stray light can be prevented from entering the photodetecting element. Similarly to the incident light to the light modulation element, polarized light having a small angle with respect to the optical axis is preferentially incident on the light detection element. As a result, the projector of the present invention can detect the amount of light highly correlated with the light contributing to the image display, and can accurately control the light source and the light modulation element.

In the projector according to the aspect of the invention, the first incident angle limiting member and the second incident angle limiting member may be configured by a diaphragm having an opening that transmits light incident at the relatively small incident angle. .
According to this configuration, the incident angle limiting member can be realized with a simple configuration.

In the projector according to the aspect of the invention, it is preferable that the diaphragm is disposed at least one of between the light source and the polarization separation element and between the polarization separation element and the light detection element.
According to this configuration, by disposing the diaphragm between the light source and the polarization separation element, stray light can be prevented from entering the light detection element before light enters the polarization separation element. Further, by arranging the diaphragm between the polarization separation element and the light detection element, it is possible to suppress the stray light from entering the light detection element immediately before the light enters the light detection element.

In the projector according to the aspect of the invention, it is preferable that a surface of the incident angle limiting member facing the polarization separation element is a light absorption surface.
According to this configuration, it is possible to prevent the light reflected by the surface of the incident angle limiting member facing the polarization separation element from becoming stray light again.

  In order to achieve the above object, a projector according to an aspect of the invention includes a light source, and a polarization separation element that separates light emitted from the light source into a first polarization and a second polarization whose polarization directions are orthogonal to each other. , One of the first polarized light and the second polarized light is incident, the polarization state of the incident polarized light is modulated based on an image signal, and the modulated polarized light is directed to the polarization separation element Based on the detection result of the light detection element, the light detection element for detecting the light quantity of the other polarization of the first polarization and the second polarization, A control unit that controls at least one of a light source and the light modulation element, and provided between the light source and the polarization separation element or between the polarization separation element and the light detection element, and having a predetermined polarization state A polarizing element that transmits polarized light The polarization element includes a first polarization element provided between the light source and the polarization separation element, and a second polarization element provided between the polarization separation element and the light detection element. The first polarizing element transmits polarized light having the same polarization direction as the polarized light incident on the light modulation element, and absorbs part of the polarized light having a polarization direction orthogonal to the polarized light incident on the light modulation element; A part of the polarized light having a polarization direction orthogonal to the polarized light incident on the light modulation element is transmitted; the second polarizing element transmits a polarized light having a polarization direction orthogonal to the polarized light incident on the light modulation element; It is characterized in that it absorbs polarized light having the same polarization direction as the polarized light incident on the light modulation element.

  In the projector according to the aspect of the invention, the light detecting element detects the other polarized light of the first polarized light and the second polarized light, that is, the light quantity of the polarized light not incident on the light modulating element, and the control unit detects the light. Based on the detection result of the detection element, at least one of the light source and the light modulation element is controlled. Therefore, the light detection element can be arranged at a position out of the optical path of the polarized light that contributes to the image, so that accurate light amount detection is performed regardless of the display content without being affected by the return light from the reflection type light modulation element. be able to.

  In addition, various stray light exists in the optical path of the projector, and stray light becomes a factor that reduces the detection accuracy of the light amount. For example, stray light is a polarization component that is not supposed to be present in each optical path because the polarization state is disturbed when reflected or scattered by various optical components. Here, since the projector of the present invention includes the polarizing element between the light source and the polarization separation element or between the polarization separation element and the light detection element, the stray light is incident on the light detection element. Is suppressed. As a result, the projector of the present invention can detect the amount of light highly correlated with the light contributing to the image display, and can accurately control the light source and the light modulation element.

In the projector according to the aspect of the invention, the polarizing element is a transmission / absorption type linearly polarizing plate that transmits linearly polarized light having a predetermined vibration direction and absorbs linearly polarized light having a vibration direction orthogonal to the predetermined vibration direction. It is desirable.
According to this configuration, it is possible to reliably prevent stray light from entering the light detection element, and to prevent polarized light that cannot pass through the linearly polarizing plate from becoming stray light again.

In the projector according to the aspect of the invention, the linearly polarizing plate may be provided between the light source and the polarization separation element, and may be polarized light incident on the light modulation element among the first polarized light and the second polarized light. It is desirable to transmit polarized light having the same polarization direction and absorb polarized light having a polarization direction orthogonal to the polarized light incident on the light modulation element.
According to this configuration, the polarization component disturbed by the optical component between the light source and the polarization separation element can be removed, but there is no adverse effect such as loss of polarized light incident on the light modulation element. Thereby, the precision of light quantity detection can be improved.

In the projector according to the aspect of the invention, the linearly polarizing plate is provided between the polarization separation element and the light detection element, and is incident on the light modulation element among the first polarization and the second polarization. It is desirable to transmit polarized light having a polarization direction orthogonal to the polarized light and absorb polarized light having the same polarization direction as the polarized light incident on the light modulation element.
According to this configuration, it is possible to prevent the polarized light that should be originally separated by the polarization separation element and should not be incident on the light modulation element from entering the light modulation element. Thereby, the precision of light quantity detection can be improved.

In the projector according to the aspect of the invention, it is preferable that an optical path length between the polarization separation element and the light modulation element is equal to an optical path length between the polarization separation element and the light detection element.
According to this configuration, the amount of light in the state in which the polarized light is focused on the light detection surface of the light detection element and imaged is the same as the focused light is focused on the image forming surface of the light modulation element. Detection can be performed.

  In order to achieve the above object, a projector according to an aspect of the invention includes a light source, and a polarization separation element that separates light emitted from the light source into a first polarization and a second polarization whose polarization directions are orthogonal to each other. , One of the first polarized light and the second polarized light is incident, the polarization state of the incident polarized light is modulated based on an image signal, and the modulated polarized light is directed to the polarization separation element Based on the detection result of the light detection element, the light detection element for detecting the light quantity of the other polarization of the first polarization and the second polarization, A control unit that controls at least one of a light source and the light modulation element, and an optical path length between the polarization separation element and the light detection element is between the polarization separation element and the light modulation element. Longer than the optical path length, the light detection element is the polarization It is disposed on the optical axis connecting the release element and the light detecting element, characterized in that is.

  In the projector according to the aspect of the invention, the light detecting element detects the other polarized light of the first polarized light and the second polarized light, that is, the light quantity of the polarized light not incident on the light modulating element, and the control unit detects the light. Based on the detection result of the detection element, at least one of the light source and the light modulation element is controlled. Therefore, the light detection element can be arranged at a position out of the optical path of the polarized light that contributes to the image, so that accurate light amount detection is performed regardless of the display content without being affected by the return light from the reflection type light modulation element. be able to.

  In addition, various stray light exists in the optical path of the projector, and stray light becomes a factor that reduces the detection accuracy of the light amount. The stray light is, for example, light reflected and scattered by various optical components and the like, and generally has a large angle with respect to the optical axis of the optical component. Therefore, light having a small angle with respect to the optical axis is distributed at the center of the optical path, and light having a large angle with respect to the optical axis, that is, stray light is distributed at the peripheral portion of the optical path. Here, in the projector of the present invention, the optical path length between the polarization separation element and the light detection element is longer than the optical path length between the polarization separation element and the light modulation element, that is, as viewed from the light source side. The detection element is arranged behind the original imaging position. Further, since the light detection element is arranged on the optical axis connecting the polarization separation element and the light detection element, the light at the center of the optical path is preferentially incident on the light detection element. Thereby, it is suppressed that a photon detection element detects said stray light. As a result, the projector of the present invention can detect the amount of light highly correlated with the light contributing to the image display, and can accurately control the light source and the light modulation element.

In the projector according to the aspect of the invention, as the light modulation element, a first light modulation element that modulates polarization of a first color, and a second light that modulates polarization of a second color different from the first color. A first light detecting element that detects the amount of polarized light of the first color, and a second light that detects the amount of polarized light of the second color as the light detecting element. You may employ | adopt the structure provided with the detection element at least.
According to this configuration, the amount of light can be detected for each color different from each other, so by controlling the light source and the light modulation element based on each detection result, the change in color balance due to the variation in the light amount of the light source is corrected. can do.
A projector according to one aspect of the present invention includes a light source, a light modulation element that modulates light incident from the light source based on an image signal, and emits the modulated light, and a light amount of light incident from the light source. A light detection element for detecting light, a control unit for controlling at least one of the light source and the light modulation element based on a detection result of the light detection element, and a relative to a light detection surface of the light detection element And an incident angle limiting member that transmits light incident at a small incident angle at a higher transmittance than light incident at a relatively large incident angle with respect to the light detection surface.
In the projector according to one aspect of the invention, the incident angle limiting member may be a diaphragm having an opening that transmits light incident at the relatively small incident angle.

1 is a schematic configuration diagram illustrating a projector according to a first embodiment of the invention. It is sectional drawing which shows the principal part of the projector of this embodiment. It is a block diagram which shows the structure of the control part of the projector of this embodiment. It is a flowchart which shows operation | movement of the projector of this embodiment. It is sectional drawing which shows the principal part of the projector of 2nd Embodiment of this invention. It is sectional drawing which shows the principal part of the projector of 3rd Embodiment of this invention. It is a schematic block diagram which shows the projector of 4th Embodiment of this invention. It is a block diagram which shows the circuit structure of the projector of this embodiment. It is a flowchart which shows operation | movement of the projector of this embodiment.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The projector according to the present embodiment is a liquid crystal projector that uses a lamp as a light source and three sets of reflective liquid crystal panels for red light, green light, and blue light as light modulation elements.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.

  As shown in FIG. 1, the projector 1 according to this embodiment includes an illumination device 2 as a color light generation unit, a color separation light guide optical system 3, and each of the three color lights separated by the color separation light guide optical system 3. Reflective liquid crystal panel 4R, reflective liquid crystal panel 4G, and reflective liquid crystal panel 4B that modulate in accordance with image signals, and color light modulated by reflective liquid crystal panel 4R, reflective liquid crystal panel 4G, and reflective liquid crystal panel 4B are combined. A cross dichroic prism 5 serving as a color synthesizing optical system, and a projection optical system 6 that projects light synthesized by the cross dichroic prism 5 onto a projection surface such as a screen SCR.

  The illumination device 2 (light source) includes a lamp 8, a first lens array 9, a second lens array 10, a polarization conversion element 11, a superimposing lens 12, and an ultraviolet cut filter 15. The lamp 8 emits an illumination light beam toward the illuminated area. The first lens array 9 has a plurality of first small lenses 13 for dividing the illumination light beam emitted from the lamp 8 into a plurality of partial light beams. The second lens array 10 has a plurality of second small lenses 14 corresponding to the plurality of first small lenses 13 of the first lens array 9. The polarization conversion element 11 converts each partial light beam from the second lens array 10 into approximately one type of linearly polarized light having a uniform polarization direction and emits the converted light. The superimposing lens 12 superimposes each partial light beam emitted from the polarization conversion element 11 in the illuminated area. Further, an ultraviolet cut filter 15 is disposed on the light emission side of the lamp 8. Ultraviolet rays are removed by the ultraviolet cut filter 15, and the lifetime of the optical components arranged in the projector 1 is extended.

  The lamp 8 includes an ellipsoidal reflector 17, an arc tube 18, a secondary mirror 19, and a concave lens 20. The arc tube 18 has a light emission center near the first focal point of the ellipsoidal reflector 17. The sub mirror 19 reflects the light emitted from the arc tube 18 toward the illuminated area toward the arc tube 18. The concave lens 20 emits the focused light from the ellipsoidal reflector 17 as substantially parallel light. The lamp 8 emits a light beam having the illumination optical axis 2ax as a central axis.

The arc tube 18 has a tube bulb portion and a pair of sealing portions extending on both sides of the tube bulb portion. The tube portion is a sphere made of quartz glass, and has a pair of electrodes arranged in the sphere, and mercury, a rare gas, and a small amount of halogen enclosed in the sphere. As the arc tube 18, various arc tubes can be employed, for example, a metal halide lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, or the like.
The ellipsoidal reflector 17 has a cylindrical neck-like portion into which one sealing portion of the arc tube 18 is inserted and fixed, and a reflective concave surface that reflects light emitted from the arc tube 18 toward the second focal position. Have

The secondary mirror 19 is a reflector that covers approximately half of the bulb portion of the arc tube 18 and is arranged to face the reflective concave surface of the elliptical reflector 17. The secondary mirror 19 has the other sealing portion of the arc tube 18 inserted and fixed. The sub mirror 19 returns light that is not directed to the ellipsoidal reflector 17 out of the light emitted from the arctube 18 to the arctube reflector 18 and enters the ellipsoidal reflector 17.
The concave lens 20 is disposed on the illuminated area side of the ellipsoidal reflector 17. The concave lens 20 emits light from the ellipsoidal reflector 17 toward the first lens array 9.

  The first lens array 9 has a function as a light beam splitting optical element that splits the light from the concave lens 20 into a plurality of partial light beams. The first lens array 9 has a configuration in which a plurality of first small lenses 13 are arranged in a matrix of a plurality of rows and a plurality of columns in a plane orthogonal to the illumination optical axis 2ax. Although not illustrated, the outer shape of the first small lens 13 is similar to the outer shape of the image forming areas of the reflective liquid crystal panels 4R, 4G, and 4B.

  The second lens array 10, together with the superimposing lens 12, places the images of the first small lenses 13 of the first lens array 9 in the vicinity of the image forming areas of the reflective liquid crystal panel 4R, the reflective liquid crystal panel 4G, and the reflective liquid crystal panel 4B. It has a function to form an image. Similar to the first lens array 9, the second lens array 10 has a configuration in which a plurality of second small lenses 14 are arranged in a matrix of a plurality of rows and a plurality of columns in a plane orthogonal to the illumination optical axis 2ax.

  The polarization conversion element 11 emits the polarization direction of each partial light beam divided by the first lens array 9 as approximately one type of linearly polarized light having the same polarization direction. The polarization conversion element 11 transmits one polarized light (for example, P-polarized light) of the illumination light from the lamp 8 and reflects the other polarized light (for example, S-polarized light) toward the direction perpendicular to the illumination optical axis 2ax. A reflection layer that reflects light having the other polarization component reflected by the polarization separation layer in a direction parallel to the illumination optical axis 2ax, and light having one polarization component that has passed through the polarization separation layer And a phase difference plate that converts light into components. In addition, although the light which permeate | transmitted the polarization conversion element 11 turns into P polarization substantially, not all become P polarization, and S polarization is mixed.

  The superimposing lens 12 condenses a plurality of partial light beams that have passed through the first lens array 9, the second lens array 10, and the polarization conversion element 11, and reflects the reflective liquid crystal panel 4R, the reflective liquid crystal panel 4G, and the reflective liquid crystal panel 4B. It is an optical element for superimposing in the vicinity of the image forming area. The superimposing lens 12 is arranged so that the optical axis of the superimposing lens 12 and the illumination optical axis 2ax of the illuminating device 2 substantially coincide. The superimposing lens 12 may be composed of a compound lens in which a plurality of lenses are combined.

  The color separation light guide optical system 3 includes a color separation optical system 22, a reflection mirror 23, a reflection mirror 24, a dichroic mirror 25, a polarization beam splitter 26, a polarization beam splitter 27, and a polarization beam splitter 28. The color separation light guide optical system 3 separates the illumination light beam emitted from the superimposing lens 12 into three color lights of red light LR, green light LG, and blue light LB, and each color light is an object to be illuminated 3 It has a function of leading to the two reflective liquid crystal panels 4R, the reflective liquid crystal panel 4G, and the reflective liquid crystal panel 4B.

  The color separation optical system 22 includes two color separation filters 30 and a color separation filter 31 on which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam in another wavelength region is formed on a substrate. The illumination light beam from the superimposing lens 12 is separated into blue light and other color lights (red light and green light) by the color separation optical system 22.

  The blue light LB separated by the color separation optical system 22 is reflected by the reflection mirror 24 and enters the polarization beam splitter 28 via the condenser lens 32B. At this time, the illumination light beam from the illumination device 2 is aligned by the polarization conversion element 11 to approximately one type of linearly polarized light (P-polarized light) whose polarization direction is substantially aligned. The light passes through the polarizing beam splitter 28 and is incident on the reflective liquid crystal panel 4B for blue light. The condensing lens 32B is provided to convert each partial light beam from the superimposing lens 12 into a light beam substantially parallel to each principal ray. The other condensing lens 32R and condensing lens 32G are configured in the same manner as the condensing lens 32B.

The polarization beam splitter 28 is a plate-type polarization beam splitter, and has a configuration in which a polarization separation film is provided on a translucent substrate. The polarization beam splitter 28 has a function of transmitting one polarized light and reflecting the other polarized light. In the present embodiment, the polarization beam splitter 28 has a function of transmitting P-polarized light and reflecting S-polarized light. The other polarizing beam splitter 26 and the polarizing beam splitter 27 are configured in the same manner as the polarizing beam splitter 28 described above.
In the present embodiment, the polarization beam splitter 26, the polarization beam splitter 27, and the polarization beam splitter 28 correspond to the “polarization separation element” in the claims.

Color light (red light LR, green light LG) other than blue light separated by the color separation optical system 22 is reflected by the reflection mirror 23 and enters the dichroic mirror 25.
The dichroic mirror 25 is an optical element in which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam in another wavelength region is formed on a substrate. The dichroic mirror 25 is a mirror that transmits the red light LR and transmits the green light LG.

  The red light LR that has passed through the dichroic mirror 25 passes through the condenser lens 32R and the polarization beam splitter 26 and is incident on the reflective liquid crystal panel 4R for red light. On the other hand, the green light LG passes through the condensing lens 32G and the polarization beam splitter 27, and enters the reflective liquid crystal panel 4G for green light.

  The reflective liquid crystal panel 4R, the reflective liquid crystal panel 4G, and the reflective liquid crystal panel 4B modulate illumination light in accordance with an image signal, and are light modulation elements as objects to be illuminated by the illumination device 2. The reflective liquid crystal panel 4R, the reflective liquid crystal panel 4G, and the reflective liquid crystal panel 4B include a pair of substrates that sandwich the liquid crystal layer and a reflective layer (or reflective electrode) disposed on the substrate side facing the substrate on the light incident side. And. Further, as shown in FIG. 1, on the surface opposite to the light incident side of the reflective liquid crystal panel 4R, reflective liquid crystal panel 4G, and reflective liquid crystal panel 4B, there are radiating fins 33R, radiating fins 33G, and radiating fins 33B. It is arranged.

In front of the cross dichroic prism 5, a polarizing plate 34R, a polarizing plate 34G, and a polarizing plate 34B are arranged. The cross dichroic prism 5 is an optical element that synthesizes an optical image modulated for each color light emitted from the polarizing plate 34R, the polarizing plate 34G, and the polarizing plate 34B to form a color image. The cross dichroic prism 5 has a substantially square shape in plan view in which four right angle prisms are bonded together, and a dielectric multilayer film is formed on the substantially X-shaped interface in which the right angle prisms are bonded together. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects the blue light LB, and the dielectric multilayer film formed at the other interface reflects the red light LR. By these dielectric multilayer films, the blue light LB and the red light LR are bent and aligned with the traveling direction of the green light LG, so that the three color lights are synthesized.
The color image formed by the light emitted from the cross dichroic prism 5 is enlarged and projected by the projection optical system 6 to form an image on the screen SCR.

As described above, the illumination light beam from the illuminating device 2 is substantially aligned with the P-polarized light by the polarization conversion element 11, and the blue P-polarized light is transmitted through the polarization beam splitter 28 to the blue reflective liquid crystal panel 4B. Incident. However, in reality, not all the light transmitted through the polarization conversion element 11 is converted to P-polarized light, but S-polarized light is also mixed. Therefore, the S-polarized light incident on the polarization beam splitter 28 is reflected by the polarization beam splitter 28. In the blue light path, a light sensor 36 (light detection element) is provided on the S-polarized light path reflected by the polarization beam splitter 28. Further, a first diaphragm 37 (incident angle limiting member) is provided between the condenser lens 32B and the polarization beam splitter. A second diaphragm 38 (incident angle limiting member) is provided between the polarization beam splitter 28 and the optical sensor.
In this embodiment, “P-polarized light” corresponds to “first polarized light” in the claims, and “S-polarized light” corresponds to “second polarized light” in the claims. “P-polarized light” corresponds to “one polarized light” in the claims, and “S-polarized light” corresponds to “other polarized light” in the claims.

FIG. 2 is an enlarged cross-sectional view of the configuration around the polarizing beam splitter 28.
Here, the action of the reflective liquid crystal panel will be described by taking the reflective liquid crystal panel 4B for blue light as an example. However, the operation is the same for the reflective liquid crystal panel 4R for red light and the reflective liquid crystal panel 4G for green light.
In the reflective liquid crystal panel 4B, the alignment state of the liquid crystal molecules changes according to the voltage applied to the liquid crystal layer. For example, when the liquid crystal layer is a vertically aligned (Vertical Alien, VA) liquid crystal, if the applied voltage is 0 V, the polarization state does not change when incident light (P-polarized light) is transmitted through the liquid crystal layer, so that P-polarized light is emitted. . On the other hand, when the applied voltage is 5 V, the polarization state changes when incident light (P-polarized light) passes through the liquid crystal layer, and S-polarized light is emitted. When the applied voltage is an intermediate value between 0V and 5V, light in which P-polarized light and S-polarized light are mixed is emitted. When S-polarized light is emitted from the reflective liquid crystal panel 4B, the S-polarized light is reflected by the polarizing beam splitter 28 and projected on the screen SCR via the cross dichroic prism 5 and the projection optical system 6 at the subsequent stage. Become. When P-polarized light is emitted from the reflective liquid crystal panel 4B, the P-polarized light is transmitted through the polarization beam splitter 28 and returns to the illumination device 2 side, so that dark display is obtained.

In the present embodiment, among the light incident on the polarization beam splitter 28 from the illumination device 2, P-polarized light is light used for image display, and S-polarized light is light not used for image display. An optical sensor 36 is disposed at a position where S-polarized light that enters the polarization beam splitter 28 from the illumination device 2 and is reflected by the polarization beam splitter 28 can be detected. On the other hand, the return light from the reflective liquid crystal panel 4B does not reach the position of the optical sensor 36 regardless of whether it is P-polarized light or S-polarized light. With such a configuration, the amount of light emitted from the illumination device 2 can be accurately detected without depending on the content of the image display by the reflective liquid crystal panel 4B.
In particular, it is desirable that the distance (optical path length) between the polarizing beam splitter 28 and the optical sensor 36 is equal to the distance (optical path length) between the polarizing beam splitter 28 and the reflective liquid crystal panel 4B. In that case, the optical sensor 36 is disposed at the imaging position. At this time, S-polarized light that does not contribute to image display forms an image on the light detection surface 36 a of the optical sensor 36.

  In general, various stray light exists in the optical path of the projector, and stray light becomes a factor that decreases the detection accuracy of the light amount by the optical sensor. Stray light is light reflected and scattered by various optical components and the like, and has a larger angle component with respect to the optical axis than normal light used for image display. Here, since the projector 1 of the present embodiment includes the first diaphragm 37 and the second diaphragm 38, light having a small angle component with respect to the optical axis ax, that is, the light detection surface 36 a of the light sensor 36. The light of the angle component incident at a relatively small incident angle passes through the opening 37a of the first diaphragm 37 and the opening 38a of the second diaphragm 38. On the other hand, light having a large angle component with respect to the optical axis ax, that is, light having an angle component incident at a relatively large incident angle with respect to the light detection surface 36a of the optical sensor 36, is formed by the opening 37a and the opening. 38 a cannot be transmitted, and is blocked by the first diaphragm 37 and the second diaphragm 38. In this way, light including stray light is removed by the first diaphragm 37 and the second diaphragm 38.

  For the first diaphragm 37, it is desirable to perform a process such as forming a layer that absorbs light on the surface 37b facing the polarization beam splitter 28, and to make this surface a light absorbing surface. Accordingly, it is possible to prevent the P-polarized light reflected by the reflective liquid crystal panel 4B and transmitted through the polarization beam splitter 28 from being reflected by the surface of the first diaphragm 37 and becoming stray light again. Similarly, for the second diaphragm 38, it is desirable that the surface 38b facing the polarization beam splitter 28 be a light absorption surface. Thereby, it is possible to prevent S-polarized light from being reflected on the surface of the second diaphragm 38 and becoming stray light again.

  In the projector 1 according to the present embodiment, the control unit 41 includes a signal processing unit 42 and a liquid crystal driving unit 43 as shown in FIG. The signal processing unit 42 performs a startup sequence, safety management, image signal correction, and the like of the entire system of the projector 1. In particular, for the correction of the image signal, the signal processing unit 42 acquires the output of the light amount detection result from the optical sensor 36 and then corrects the image signal in accordance with the change in the light amount of the illumination device 2. The liquid crystal driving unit 43 outputs a driving voltage for driving the reflective liquid crystal panels 4R, 4G, and 4B for each color light based on the image signal corrected by the signal processing unit. With this configuration, the control unit 41 controls the reflective liquid crystal panels 4R, 4G, and 4B so as to compensate for the light amount fluctuation of the illumination device 2.

In addition, the control unit 41 receives an output from the optical sensor 36 and issues a warning to the user when the light amount of the lighting device 2 decreases.
FIG. 4 is a flowchart showing the processing procedure of the signal processing unit 42.
First, the signal processing unit 42 acquires an output including a light amount detection result from the optical sensor 36 (step S1 in FIG. 4).

Next, the signal processing unit 42 determines whether or not the output signal from the optical sensor 36 is equal to or smaller than a predetermined value, that is, whether or not the light amount of the illumination device 2 is equal to or smaller than the predetermined light amount (FIG. 4). Step S2).
Here, when the output signal from the optical sensor 36 exceeds a predetermined value, that is, when the light amount of the illumination device 2 exceeds the predetermined light amount (NO in step S2 in FIG. 4), steps S1 and S2 in FIG. repeat. Steps S1 and S2 may be repeated intermittently, and the repetition interval may be set as appropriate.

  On the other hand, when the output signal from the optical sensor 36 is equal to or less than a predetermined value, for example, when the light amount of the lighting device 2 becomes equal to or less than the predetermined light amount due to, for example, change with time of the arc tube (YES in step S2 in FIG. 4). The signal processing unit 42 transmits an image signal to the liquid crystal driving unit 43, and the reflective liquid crystal panels 4R, 4G, and 4B display to prompt the user to replace the lamp (step S3 in FIG. 4).

  In the projector 1 of the present embodiment, the light sensor 36 detects the amount of S-polarized light that is not incident on the blue light liquid crystal panel 4B, and the control unit 41 is a reflective liquid crystal for each color light based on the detection result of the light sensor 36. The image signals supplied to the panels 4R, 4G, 4B are corrected. Therefore, since the optical sensor 36 can be arranged at a position deviated from the optical path of P-polarized light that contributes to image display, the optical sensor 36 is not affected by the return light from the reflective liquid crystal panel 4B, and the optical sensor 36 is not affected by the display content. Accurate light quantity detection can be performed.

  In addition, various stray light exists in the optical path of the projector, and stray light becomes a factor that reduces the detection accuracy of the light amount. On the other hand, since the projector 1 according to the present embodiment includes the first diaphragm 37 and the second diaphragm 38 described above, stray light having a large angle component with respect to the optical axis is incident on the optical sensor 36. It can be suppressed. As a result, the projector 1 according to the present embodiment can detect the amount of light having a high correlation with the light contributing to image display, and can accurately control the reflective liquid crystal panels 4R, 4G, and 4B.

  Further, in the projector 1 according to the present embodiment, for example, when the light-emitting tube 18 or the like deteriorates after long-term use, and the light amount of the lighting device 2 becomes a predetermined light amount or less, a display that prompts the user to replace the lamp I do. Therefore, the user can surely recognize that the arc tube 18 has reached the end of its life and can take appropriate measures.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector of this embodiment is the same as that of the first embodiment, and the configuration around the polarizing beam splitter is different from that of the first embodiment.
Therefore, in FIG. 5, the same code | symbol is attached | subjected to the same component as FIG. 2 of 1st Embodiment, and description is abbreviate | omitted.

  In the projector of this embodiment, as shown in FIG. 5, the optical sensor 36 has a distance T1 from the light incident position on the polarizing beam splitter 28 to the reflective liquid crystal panel 4B from the light incident position on the polarizing beam splitter 28. It is arranged at a position farther than the distance T2. That is, in this embodiment, the distance T1 (optical path length) between the polarizing beam splitter 28 and the optical sensor 36 is larger than the distance T2 (optical path length) between the polarizing beam splitter 28 and the reflective liquid crystal panel 4B. long. Further, the optical sensor 36 is arranged at the center of the optical path of S-polarized light reflected by the polarization beam splitter 28.

  As described in the first embodiment, when the optical path length between the polarizing beam splitter 28 and the optical sensor 36 is equal to the optical path length between the polarizing beam splitter 28 and the reflective liquid crystal panel 4B, the optical sensor 36 is It is arranged at the imaging position. At this time, S-polarized light that does not contribute to image display forms an image on the light detection surface 36 a of the optical sensor 36. In contrast, in the present embodiment, the distance T1 between the polarizing beam splitter 28 and the optical sensor 36 is longer than the distance T2 between the polarizing beam splitter 28 and the reflective liquid crystal panel 4B. Is arranged at a position farther from the imaging position. S-polarized light once imaged again spreads at a position farther from the imaging position, S-polarized light having a small angular component is distributed at the center of the optical path, and S-polarized light having a large angular component is distributed at the periphery of the optical path. Therefore, by arranging the optical sensor 36 at the center of the optical path of S-polarized light, S-polarized light having a small angle component preferentially enters the optical sensor 36, and S-polarized light having a large angular component, that is, stray light, enters the optical sensor 36. It becomes difficult to do.

  Also in the projector according to the present embodiment, the light sensor 36 can accurately detect the amount of light regardless of the display content without being affected by the return light from the reflective liquid crystal panel 4B. The same effects as those of the first embodiment can be obtained, in which the amount of light having a high correlation with the light contributing to the display can be detected and the reflective liquid crystal panels 4R, 4G, and 4B can be accurately controlled. Moreover, in this embodiment, since the aperture used in the first embodiment is not necessary, the number of parts can be reduced as compared with the first embodiment.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector of this embodiment is the same as that of the first embodiment, and the configuration around the polarizing beam splitter is different from that of the first embodiment.
Therefore, in FIG. 6, the same code | symbol is attached | subjected to the same component as FIG. 2 of 1st Embodiment, and description is abbreviate | omitted.

The projector according to the first embodiment includes the first diaphragm 37 between the condenser lens 32 </ b> B and the polarization beam splitter 28, and includes the second diaphragm 38 between the polarization beam splitter 28 and the optical sensor 36. . On the other hand, the projector according to the present embodiment uses the first polarizing plate 45 and the second polarizing plate 46 instead of the stop. That is, as shown in FIG. 6, the projector according to the present embodiment includes a first polarizing plate 45 between the condenser lens 32 </ b> B and the polarizing beam splitter 28, and between the polarizing beam splitter 28 and the optical sensor 36. A second polarizing plate 46 is provided.
In the present embodiment, the first polarizing plate 45 and the second polarizing plate 46 correspond to a “polarizing element” in the claims.

  The first polarizing plate 45 transmits the polarized light that is incident on the reflective liquid crystal panel 4B through the polarizing beam splitter 28, that is, P-polarized light, and absorbs the polarized light that is not incident on the reflective liquid crystal panel 4B, that is, S-polarized light. It is a transmission / absorption type linearly polarizing plate. That is, the first polarizing plate 45 transmits polarized light having the same polarization direction as the polarized light incident on the reflective liquid crystal panel 4B, and absorbs polarized light having a polarization direction orthogonal to the polarized light incident on the reflective liquid crystal panel 4B. The first polarizing plate 45 generally absorbs S-polarized light, but does not absorb all of it, but transmits a part of S-polarized light.

  The second polarizing plate 46 transmits the polarized light that does not enter the reflective liquid crystal panel 4B through the polarizing beam splitter 28, that is, S-polarized light, and absorbs the polarized light that enters the reflective liquid crystal panel 4B, that is, P-polarized light. It is a transmission / absorption type linearly polarizing plate. That is, the second polarizing plate 46 transmits polarized light having a polarization direction orthogonal to the polarized light incident on the reflective liquid crystal panel 4B, and absorbs polarized light having the same polarization direction as the polarized light incident on the reflective liquid crystal panel 4B. The second polarizing plate 46 generally absorbs P-polarized light, but does not absorb all of it, and transmits part of P-polarized light.

  Various stray light exists in the optical path of the projector, and the stray light becomes a factor of reducing the light amount detection accuracy. For example, when the stray light is reflected and scattered by various optical components or the like, the polarization state is disturbed, and a polarization component that should not be originally included in each optical path is included. Here, since the projector according to the present embodiment includes the first polarizing plate 45 that absorbs S-polarized light in the preceding stage of the polarizing beam splitter 28, the polarizing conversion element 11 that emits P-polarized light to the polarizing beam splitter 28. The stray light (S-polarized light) generated by each optical component located on the optical path of can be removed.

  Furthermore, the polarization beam splitter 28 has an incident angle dependency, and exhibits a basic polarization separation characteristic of transmitting P-polarized light and reflecting S-polarized light with respect to light incident at a small incident angle. However, light incident at a large incident angle may not necessarily exhibit the above polarization separation characteristics. Therefore, P-polarized stray light having a large angle component is reflected by the polarization beam splitter 28 and mixed in the S-polarized light toward the optical sensor 36. Here, since the projector according to the present embodiment includes the second polarizing plate 46 that absorbs the P-polarized light between the polarization beam splitter 28 and the optical sensor 36, the P-polarized stray light can also be removed.

  Also in the projector according to the present embodiment, stray light can be prevented from entering the optical sensor 36, light quantity detection highly correlated with light contributing to image display can be performed, and the liquid crystal panels 4R, 4G, and 4B can be accurately controlled. The same effect as the first and second embodiments can be obtained.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS.
The projector according to this embodiment uses a first illumination device that emits blue light and a second illumination device that emits yellow light as illumination devices, the arrangement of optical sensors, and control based on detection results of optical sensors. The content is different from the projector of the first embodiment.
Of the basic configuration of the projector according to the present embodiment, the configuration excluding the illumination device according to the first embodiment and a part of the color separation light guide optical system is the same as that of the first embodiment.
Therefore, in FIG. 7, the same code | symbol is attached | subjected to the same component as FIG. 1 of 1st Embodiment, and description is abbreviate | omitted.

  As shown in FIG. 7, the projector 50 of the present invention includes a blue light illumination device 51 that emits blue light LB and a yellow light illumination device 52 that emits yellow light LY. The blue light illumination device 51 includes a blue laser diode array 53, a collimating lens 54, a condenser lens 55, a diffusion plate 56, a pickup lens 57, a collimating lens 58, a first lens array 9, A second lens array 10, a polarization conversion element 11, and a superimposing lens 12 are provided. The blue laser diode array 53 is, for example, a structure in which twelve blue laser diodes 59 are arranged in an array of 4 × 3. The collimating lens 54 is provided corresponding to each blue laser diode 59.

  The blue light LB emitted from the blue laser diode 59 is collimated by the collimating lens 54, then condensed by the condensing lens 55, and irradiated on the diffusion plate 56, thereby forming a point light source. Blue diffused light from each point light source on the diffusion plate 56 passes through the pickup lens 57 and is collimated by the collimating lens 58 and then enters the first lens array 9. Since the action of light after the first lens array 9 is the same as that of the first embodiment, the description thereof is omitted.

  The yellow light illumination device 52 includes an excitation laser diode array 60, a collimating lens 54, a condensing lens 55, a phosphor substrate 61, a pickup lens 57, a collimating lens 58, and a first lens array 9. And a second lens array 10, a polarization conversion element 11, and a superimposing lens 12. For example, the excitation laser diode array 60 includes 30 excitation laser diodes 62 arranged in an array of 6 × 5. The excitation laser diode 62 emits ultraviolet light or blue light as excitation light for exciting the phosphor. The collimating lens 54 is provided corresponding to each excitation laser diode 62. The phosphor substrate 61 is a substrate in which a phosphor layer that emits yellow light upon receiving excitation light such as ultraviolet light or blue light is formed on the substrate.

  Each excitation light emitted from the excitation laser diode 62 is collimated by the collimating lens 54, then condensed by the condensing lens 55, and irradiated onto the phosphor substrate 61 to form a point light source. The The yellow light LY emitted from each point light source on the phosphor substrate 61 passes through the pickup lens 57 and is collimated by the collimating lens 58 and then enters the first lens array 9. Since the action of light after the first lens array 9 is the same as that of the first embodiment, the description thereof is omitted. Since yellow light LY includes a red light component and a green light component, red light LR and green light LG are generated by decomposing yellow light LY with dichroic mirror 25.

  In the case of the projector 50 of the present embodiment, the blue light optical sensor 36B (first light detection element) is provided on the S-polarized light path reflected by the polarization beam splitter 28 in the blue light LB optical path. Further, a first diaphragm 37 (incident angle limiting member) is provided between the condenser lens 32B and the polarization beam splitter. A second diaphragm 38 (incident angle limiting member) is provided between the polarization beam splitter 28 and the optical sensor 36B.

  Similarly, in the optical path of the green light LG, a green light optical sensor 36G (second light detection element) is provided on the S-polarized light path reflected by the polarization beam splitter 28. A first diaphragm 37 (incident angle limiting member) is provided between the condenser lens 32G and the polarization beam splitter 28. A second diaphragm 38 (incident angle limiting member) is provided between the polarization beam splitter 28 and the optical sensor 36G.

  Similarly, a red light optical sensor 36R (third light detection element) is provided on the S-polarized light path reflected by the polarization beam splitter 28 in the optical path of the red light LR. A first diaphragm 37 (incident angle limiting member) is provided between the condenser lens 32R and the polarization beam splitter 28. A second diaphragm 38 (incident angle limiting member) is provided between the polarization beam splitter 28 and the optical sensor 36R.

  In the projector 50 of the present embodiment, as shown in FIG. 8, the control unit 64 includes a signal processing unit 65, a liquid crystal driving unit 66, a PWM signal generating unit 67, an excitation laser diode driving unit 68, and a blue laser. A diode driver 69. The signal processing unit 65 performs a startup sequence of the entire system of the projector 50, safety management, image signal correction, control of the blue laser diode 59 and the excitation laser diode 62, and the like.

  For the correction of the image signal, the signal processing unit 65 acquires the output of the light amount detection results from the red light sensor 36R, the green light sensor 36G, and the blue light sensor 36B, respectively, and then the illumination device The image signal is corrected according to the fluctuation of the light quantity of 2. The liquid crystal driving unit 66 outputs a driving voltage for driving the reflective liquid crystal panels 4R, 4G, and 4B for each color light based on the image signal corrected by the signal processing unit 65. With this configuration, the control unit 64 controls the liquid crystal panel 4R, the liquid crystal panel 4G, and the liquid crystal panel 4B so as to compensate for the light amount fluctuations of the blue laser diode array 53 and the excitation laser diode array 60.

  The signal processing unit 65 acquires the detection results of the light amounts from the red light sensor 36R, the green light sensor 36G, and the blue light sensor 36B, respectively, and then excites according to the change in the light amount of the illumination device 2. The duty ratio of the PWM signal that drives the laser diode 62 and the duty ratio of the PWM signal that drives the blue laser diode 59 are corrected. The PWM signal generation unit 67 generates a PWM signal for each laser diode based on the duty ratio corrected by the signal processing unit 65.

  The excitation laser diode driver 68 outputs a drive current for driving the excitation laser diode 62 based on the PWM signal generated by the PWM signal generator 67. Similarly, the blue laser diode driver 69 outputs a drive current for driving the blue laser diode 59 based on the PWM signal generated by the PWM signal generator 67. With this configuration, the control unit 64 controls the excitation laser diode array 60 so as to compensate for the light amount fluctuation of the excitation laser diode array 60, and also controls the blue laser diode so as to compensate for the light quantity fluctuation of the blue laser diode array 53. The array 53 is controlled.

The control unit 64 not only changes the absolute value of the light quantity of each color light but also changes the light quantity of the excitation laser diode array 60 and the blue laser diode array 53 and each liquid crystal panel when the light quantity ratio of each color light changes. The color balance of the display image is adjusted by correcting the gamma characteristics of 4R, 4G, and 4B.
The flowchart of FIG. 9 shows the processing procedure of the signal processing unit 65.
First, the signal processing unit 65 acquires an output including a light amount detection result from the red light optical sensor 36R, the green light optical sensor 36G, and the blue light optical sensor 36B (step S1 in FIG. 9).
Next, the signal processing unit 65 analyzes the ratio (RB output ratio) between the red light amount output from the red light sensor 36R and the blue light amount output from the blue light sensor 36B (FIG. 9). Step S2).

  Next, the signal processing unit 65 determines whether or not the RB output ratio is within an allowable value (step S3 in FIG. 9). Since the red light and the blue light are emitted from different laser diode arrays, the output of the excitation laser diode array 60 and the blue laser diode array 53 is determined by determining whether or not the RB output ratio is within an allowable value. Variations in the amount of light can be detected.

Here, if the RB output ratio exceeds the allowable value (NO in step S3 in FIG. 9), the light amounts of the excitation laser diode array 60 and the blue laser diode array 53 are adjusted (step S4 in FIG. 9). At this time, it is preferable to adjust the light quantity of the blue laser diode array 53 that emits the blue light component that has less influence on the brightness than the excitation laser diode array 60 that emits the red light component, in terms of visibility.
Then, it returns to step S1 of FIG. The light amount adjustment of the excitation laser diode array 60 and the blue laser diode array 53 is performed until the RB output ratio falls within an allowable value.

On the other hand, when the RB output ratio is within the allowable value (YES in step S3 in FIG. 9), the signal processing unit 65 outputs the red light amount output from the red light sensor 36R and the green light sensor 36G. The ratio (RG output ratio) with the light amount output of green light is analyzed (step S5 in FIG. 9).
Next, the signal processing unit 65 determines whether or not the RG output ratio is within an allowable value (step S6 in FIG. 9). Since both the red light and the green light are emitted from the excitation laser diode array 60, the light emitted from the excitation laser diode array 60 is determined by determining whether or not the RG output ratio is within an allowable value. Can be detected.

  If the RG output ratio exceeds the allowable value (NO in step S6 in FIG. 9), the gamma characteristics of the liquid crystal panels 4R, 4G, and 4B are adjusted (step S7 in FIG. 9). When the RG output ratio exceeds the allowable value, the RG output ratio cannot be changed when the light quantity of the excitation laser diode array 60 is adjusted. Therefore, when the RG output ratio exceeds the allowable value, it is dealt with by adjusting the gamma characteristics of the liquid crystal panels 4R, 4G, 4B. At this time, it is preferable to adjust the gamma characteristic of the liquid crystal panel 4R for red light while fixing the gamma characteristic of the liquid crystal panel 4G for green light, which has a great influence on the brightness, from the relationship of visibility.

Then, it returns to step S1 of FIG. Therefore, the gamma characteristics of the liquid crystal panels 4R, 4G, and 4B are adjusted until the RB output ratio is within the allowable value and the RG output ratio is within the allowable value.
By such a procedure, the color balance of the display image can be adjusted.

  In the projector 50 according to the present embodiment, a red light sensor 36R, a green light sensor 36G, and a blue light sensor 36B, a first diaphragm 37, and a second diaphragm 38 are provided on the optical paths of the respective color lights. , The incidence of stray light on each optical sensor is suppressed, and the light quantity detection having a high correlation with the light contributing to the image display can be performed. Based on the light amount detection result, it is possible to accurately correct the color balance variation caused by the variation of each laser diode array 53, 60 with the passage of time.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first embodiment, the first diaphragm is provided between the condenser lens and the polarization beam splitter, and the second diaphragm is provided between the polarization beam splitter and the optical sensor. A configuration having only one aperture may be used. Further, the aperture of the first embodiment and the polarizing plate of the third embodiment may be combined with the configuration in which the photosensor of the second embodiment is arranged farther from the imaging position. According to this configuration, it is possible to more reliably eliminate the influence of stray light. Further, the incident angle limiting member is not necessarily limited to the stop having the opening, and any member having the light transmission part in the center and the light shielding part in the peripheral part can be used. Alternatively, an arbitrary member having a relatively high transmittance portion in the center and a relatively low transmittance portion in the peripheral portion may be used.

  In the third embodiment, the first polarizing plate is provided between the condenser lens and the polarizing beam splitter, and the second polarizing plate is provided between the polarizing beam splitter and the optical sensor. The structure provided only with one of the polarizing plates may be sufficient. In the fourth embodiment, an example is shown in which photosensors are arranged in all of the light paths of three color lights of red light, green light, and blue light, and the color balance is corrected. However, instead of this configuration, red light and green light are corrected. It is good also as a structure which arrange | positions an optical sensor in the optical path of two color lights of either one of light and blue light. In that case, the change in the ratio of the red light component and the green light component contained in the yellow light cannot be detected, but the light amount fluctuation of the light source device can be detected, and the light source device and the liquid crystal panel are controlled based on the detection result. can do.

  DESCRIPTION OF SYMBOLS 1,50 ... Projector, 2 ... Illuminating device (light source), 4R, 4G, 4B ... Reflection type liquid crystal panel (light modulation element) 26, 27, 28 ... Polarization beam splitter (polarization separation element), 36 ... Optical sensor (light) Detection element), 37... First aperture (incident angle limiting member), 38... Second aperture (incident angle limiting member), 41, 64... Control unit, 45. ... second polarizing plate (polarizing element), 51 ... blue light illumination device (light source), 52 ... yellow light illumination device (light source), 36R ... red light sensor (light detection element), 36G ... green light Light sensor (light detection element), 36B... Blue light sensor (light detection element).

The present invention relates to a projector and a projector control method .

In order to achieve the above object, a projector according to the present invention includes a first illumination device that emits blue light, a second illumination device that emits colored light including at least red light, and the first illumination device. A blue light polarization separation element that separates the emitted blue light into first polarized light and second polarized light whose polarization directions are orthogonal to each other, and red light included in the colored light emitted from the second illumination device Are separated into first polarized light and second polarized light whose polarization directions are orthogonal to each other, and the first polarized light and the second polarized light separated from the blue light. One of the polarized light is incident, the polarization state of the incident polarized light is modulated based on the image signal, and the modulated polarized light is emitted toward the blue light polarization separation element. And the first polarized light separated from the red light Reflection in which one of the second polarized light is incident, the polarization state of the incident polarized light is modulated based on an image signal, and the modulated polarized light is emitted toward the polarization separation element for red light Type red light modulating element, blue light detecting element for detecting the amount of light of the other of the first polarized light and the second polarized light separated from the blue light, and the red light A light detection element for red light that detects the amount of light of the other of the first polarization and the second polarization separated from light; the light detection element for blue light; and the light detection for red light A controller that controls any one of the first illumination device, the second illumination device, the blue light modulation element, and the red light modulation element based on a detection result from an element. The control unit is configured to detect the blue light detected by the blue light detection element. It is determined whether or not a first ratio between the amount of polarized light of light and the amount of polarized light of the red light detected by the light detection element for red light is within an allowable value, and the first ratio is The light quantity of the first lighting device is adjusted when the allowable value is exceeded.
The projector of the present invention includes a light source, a polarization separation element that separates light emitted from the light source into a first polarization and a second polarization whose polarization directions are orthogonal to each other, and the first polarization. Reflective light that enters one of the second polarized light, modulates the polarization state of the incident polarized light based on an image signal, and emits the modulated polarized light toward the polarization separation element A modulation element; a light detection element that detects the amount of light of the other of the first polarization and the second polarization; the light source and the light modulation element based on a detection result of the light detection element; A control unit for controlling at least one of the light source, the first incident angle limiting member provided between the light source and the polarization separation element, and a first part provided between the polarization separation element and the light detection element. An incident angle limiting member including two incident angle limiting members; Each of the first incident angle limiting member and the second incident angle limiting member is configured to detect light incident at a relatively small incident angle with respect to a light detection surface of the light detection element. It is characterized in that the light is transmitted with a higher transmittance than light incident at a relatively large incident angle with respect to the surface.

Claims (9)

A light source;
A polarization separation element that separates the light emitted from the light source into a first polarization and a second polarization whose polarization directions are orthogonal to each other;
One of the first polarized light and the second polarized light is incident, the polarization state of the incident polarized light is modulated based on an image signal, and the modulated polarized light is directed toward the polarization separation element. A reflective light modulation element that emits; and
A light detecting element for detecting a light amount of the other polarized light of the first polarized light and the second polarized light;
A control unit that controls at least one of the light source and the light modulation element based on a detection result of the light detection element;
A first incident angle limiting member provided between the light source and the polarization separation element; and a second incident angle limiting member provided between the polarization separation element and the light detection element. An incident angle limiting member;
With
Each of the first incident angle limiting member and the second incident angle limiting member emits light incident at a relatively small incident angle with respect to the light detection surface of the light detection element with respect to the light detection surface. And a projector having a higher transmittance than light incident at a relatively large incident angle.   2. The diaphragm according to claim 1, wherein each of the first incident angle limiting member and the second incident angle limiting member is an aperture having an opening that transmits light incident at the relatively small incident angle. Projector.   The surface of the first incident angle limiting member facing the polarization separation element and the surface of the second incident angle limiting member facing the polarization separation element are light absorption surfaces. 2. The projector according to 2. A light source;
A polarization separation element that separates the light emitted from the light source into a first polarization and a second polarization whose polarization directions are orthogonal to each other;
One of the first polarized light and the second polarized light is incident, the polarization state of the incident polarized light is modulated based on an image signal, and the modulated polarized light is directed toward the polarization separation element. A reflective light modulation element that emits; and
A light detecting element for detecting a light amount of the other polarized light of the first polarized light and the second polarized light;
A control unit that controls at least one of the light source and the light modulation element based on a detection result of the light detection element;
A polarizing element that is provided between the light source and the polarization separation element or between the polarization separation element and the light detection element and transmits polarized light in a predetermined polarization state;
With
The polarization element includes a first polarization element provided between the light source and the polarization separation element, and a second polarization element provided between the polarization separation element and the light detection element. Including
The first polarizing element transmits polarized light having the same polarization direction as the polarized light incident on the light modulating element, absorbs a part of polarized light having a polarization direction orthogonal to the polarized light incident on the light modulating element, and transmits the light. Transmit a part of the polarized light in the polarization direction orthogonal to the polarized light incident on the modulation element,
The second polarizing element transmits polarized light having a polarization direction orthogonal to the polarized light incident on the light modulation element and absorbs polarized light having the same polarization direction as the polarized light incident on the light modulation element. .   A transmission / absorption type straight line in which the first polarizing element and the second polarizing element transmit linearly polarized light having a predetermined vibration direction and absorb linearly polarized light having a vibration direction orthogonal to the predetermined vibration direction. The projector according to claim 4, wherein the projector is a polarizing plate.   The linearly polarizing plate as the first polarizing element transmits polarized light having the same polarization direction as the polarized light incident on the light modulating element out of the first polarized light and the second polarized light, and the light modulation The projector according to claim 5, wherein the projector absorbs polarized light having a polarization direction orthogonal to polarized light incident on the element.   The linearly polarizing plate, which is the second polarizing element, transmits polarized light having a polarization direction orthogonal to polarized light incident on the light modulation element among the first polarized light and the second polarized light, and transmits the light. The projector according to claim 5, wherein the projector absorbs polarized light having the same polarization direction as polarized light incident on the modulation element.   The optical path length between the polarization separation element and the light modulation element and the optical path length between the polarization separation element and the light detection element are equal to each other. The projector according to item. The light modulation element includes at least a first light modulation element that modulates polarized light of a first color and a second light modulation element that modulates polarized light of a second color different from the first color. Prepared,
The photodetecting element includes at least a first photodetecting element that detects the amount of polarized light of the first color, and a second photodetecting element that detects the amount of polarized light of the second color. The projector according to claim 1, wherein the projector is a projector.

Images