JP2013164555A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector that can suppress irradiation of high-output light to a screen SCR and secure safety.SOLUTION: A projector includes: a light source device 1 provided with an excitation light source 10 for emitting excitation light and a phosphor layer 32; an optical modulation device 400B for forming an image by being illuminated by the light source device 1; a fluorescence intensity detection device 50 for detecting the intensity of a part of light emitted from the light source device 1; and a control device 70 that causes the excitation light source 10 to start emitting the excitation light in a state where the optical modulation device 400B is held in a light shielding state and determines whether or not the light shielding state of the optical modulation device 400B is released on the basis of the detection result by the fluorescence intensity detection device 50.

Description

  The present invention relates to a projector.

  In recent years, laser light sources have attracted attention as high-efficiency light sources with a wide color gamut for high performance projectors. For example, the projector of Patent Document 1 includes a plurality of light sources that emit laser light as excitation light, and a plurality of phosphor layers arranged on a rotating plate.

JP 2010-85740 A

  The projector of Patent Document 1 is configured to condense laser light emitted from a plurality of light sources onto a phosphor layer formed on a rotating plate. In the case of such a configuration, when the rotating plate stops in a state where the laser light is emitted from the light source, the laser light is collected at one point on the rotating plate. At this time, the portion of the rotating plate where the laser beam is condensed becomes high temperature due to the irradiation energy of the laser beam. For this reason, a portion of the rotating plate where the laser beam is condensed may be melted and a hole may be formed in the rotating plate. Even if the rotating plate does not reach a high temperature, the phosphor layer may be lost. As a result, high-power laser light penetrates through the rotating plate and leaks to the outside.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a projector that can prevent high-output light from leaking to the outside and ensure safety.

  In order to solve the above problems, a projector according to the present invention includes a light modulation device that modulates excitation light, an excitation light source that emits excitation light, and a fluorescence emission region that emits fluorescence when irradiated with the excitation light. A light source device that illuminates the light modulation device, a detection device that detects the intensity of a part of light emitted from the light source device, and the light modulation device is held in a light-shielded state. A control device that starts emitting the excitation light from the excitation light source in a state where the light modulation device is released and determines whether or not to cancel the light shielding state of the light modulation device based on a detection result by the detection device; It is characterized by including.

  According to this configuration, when there is a possibility that excitation light having a level exceeding a safe level may leak to the outside, the light-blocking state of the light modulation device is maintained, so that the excitation light can be stopped by the light modulation device. Therefore, it is possible to prevent high-output light from leaking to the outside and ensure safety.

  In the projector, the detection device includes at least one of a fluorescence intensity detection device that detects a partial intensity of the fluorescence and an excitation light intensity detection device that detects a partial intensity of the excitation light. May be.

  In the projector, the detection device includes the fluorescence intensity detection device, and the control device has a light shielding state of the light modulation device when a light intensity detected by the fluorescence intensity detection device is equal to or higher than a predetermined intensity. May be released.

  In the projector, the detection device includes the excitation light intensity detection device, and when the light intensity detected by the excitation light intensity detection device is less than a predetermined intensity, the control device The light blocking state may be canceled.

  In the projector, the detection device includes the fluorescence intensity detection device and the excitation light intensity detection device, and the control device is based on a detection result of the fluorescence intensity detection device and a detection result of the excitation light intensity detection device. The conversion efficiency of the excitation light into the fluorescence by the fluorescence emission region may be estimated, and when the estimated conversion efficiency is greater than or equal to a predetermined value, the light blocking state of the light modulation device may be canceled.

  In the projector, the fluorescent light emitting element may be a rotating plate that rotates about a predetermined rotation axis, and the fluorescent light emitting region may be provided along a rotation direction of the rotating plate.

  According to this configuration, heat generated in the rotating plate by irradiation of excitation light emitted from the excitation light source can be dissipated in a wide region along the rotation direction of the rotating plate. For this reason, it can suppress that a rotating plate melt | dissolves by irradiation of the excitation light inject | emitted from the excitation light source.

  In the projector, at least during a period in which the irradiation spot of the excitation light is located in the fluorescent light emission region, the detection device detects the intensity of a part of the light emitted from the light source device, and the detection device Based on the detection result of the period, it may be determined whether or not to cancel the light blocking state of the light modulation device.

  In the projector, the control device rotates the fluorescent light emitting element in a state where the light modulation device is held in a light-shielded state, and when the rotation speed of the fluorescent light emitting element is equal to or higher than a predetermined rotation speed, the excitation device You may start emitting the said excitation light from a light source.

  In the projector, the excitation light source may emit laser light as the excitation light.

  According to this configuration, the light condensing property is high as compared with the case where a halogen lamp, an ultrahigh pressure mercury lamp, or the like is used as the light source. Therefore, high-power light is collected on the rotating plate. At this time, a portion where the laser beam is condensed on the rotating plate is melted and a hole is easily opened. Therefore, in such a configuration, the effect of the present invention that suppresses leakage of high-output light to the outside and secures safety becomes remarkable.

It is a schematic diagram which shows the optical system of the projector which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows a fluorescence light emitting element similarly. It is a graph which shows the relationship between the intensity | strength of the fluorescence inject | emitted from a light source device, and time similarly. 4 is a flowchart showing the operation of the projector until the light blocking state of the light modulation device is released. It is a flowchart following FIG. It is a schematic diagram which shows the optical system of the projector which concerns on 2nd Embodiment of this invention. It is a graph which shows the relationship between the intensity | strength of excitation light inject | emitted from a light source device, and time similarly. 4 is a flowchart showing the operation of the projector until the light blocking state of the light modulation device is released. It is a schematic diagram which shows the optical system of the projector which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows a fluorescence light emitting element similarly. It is a graph which shows the relationship between the conversion efficiency to fluorescence, and time similarly. 4 is a flowchart showing the operation of the projector until the light blocking state of the light modulation device is released.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

(First embodiment)
FIG. 1 is a schematic diagram showing an optical system of a projector 1000 according to the first embodiment of the present invention.
As shown in FIG. 1, the projector 1000 includes a light source device 1, an illumination optical system 100, a color separation light guide optical system 200, a liquid crystal light modulation device 400R as a light modulation device, a liquid crystal light modulation device 400G, and liquid crystal light. The modulation device 400B, the cross dichroic prism 500, the projection optical system 600, the fluorescence intensity detection device 50, the drive device 60, and the control device 70 are provided.

  The light source device 1 includes an excitation light source 10, a collimator lens array 13, a condenser lens 20, a fluorescent light emitting element 30, and a collimating optical system 40. On the optical path of the excitation light emitted from the excitation light source 10, a collimator lens array 13, a condenser lens 20, a fluorescent light emitting element 30, and a collimating optical system 40 are arranged in this order. The light source device 1 illuminates the light modulation device.

  The excitation light source 10 is a laser light source array in which a plurality of laser light sources 12 are two-dimensionally arranged.

  The excitation light source 10 emits blue (emission intensity peak: around 445 nm) laser light as excitation light for exciting a fluorescent material included in the fluorescent light emitting element 30 described later. The excitation light source 10 may be an excitation light source that emits colored light having a peak wavelength other than 445 nm as long as it is light having a wavelength that can excite a fluorescent substance to be described later.

  The collimator lens array 13 is configured by two-dimensionally arranging a plurality of microlenses 130 provided corresponding to the laser light sources 12. The collimator lens array 13 is arranged such that each microlens 130 is on the beam axis of each laser beam emitted from each laser light source 12, and collimates each laser beam.

  The condenser lens 20 is composed of, for example, a convex lens. The condenser lens 20 is disposed on the beam axes of a plurality of laser beams (excitation light) incident from the collimator lens array 13 and converges the excitation light.

FIG. 2 is a perspective view of the fluorescent light emitting device 30.
The fluorescent light emitting element 30 is a so-called transmission type rotating fluorescent plate. As shown in FIGS. 1 and 2, the fluorescent light emitting element 30 is provided with a fluorescent light emitting region on a rotating plate 31 that is rotationally driven by a motor 33 around a predetermined rotation axis. The fluorescence emission region is provided around the rotation axis O of the rotating plate 31, and the phosphor layer 32 is provided in the fluorescence emission region. The rotating plate 31 is made of a material that transmits excitation light, such as glass.

  The phosphor layer 32 includes phosphor particles (not shown) and a binder. The phosphor particles are particulate fluorescent materials that absorb excitation light (blue light) having a wavelength of, for example, about 445 nm and emit fluorescence having a wavelength band of about 490 to 750 nm. This fluorescence includes green light (wavelength near 530 nm) and red light (wavelength near 630 nm).

As the phosphor particles, a commonly known YAG (yttrium, aluminum, garnet) phosphor layer can be used. For example, a YAG phosphor layer having a composition represented by (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce having an average particle diameter of 10 μm can be used. The phosphor particle forming material may be one kind, or a mixture of particles formed using two or more kinds of forming materials may be used as the phosphor particles.

  The phosphor layer 32 is irradiated with excitation light (blue light) collected by the condensing lens 20 from the surface of the rotating plate 31 opposite to the side where the phosphor layer 32 is formed. The fluorescent light emitting element 30 emits the fluorescence emitted from the phosphor layer 32 toward the side opposite to the side on which the excitation light is incident, that is, toward the collimating optical system 40. Further, the component of the excitation light that has not been converted to fluorescence by the phosphor particles is emitted from the fluorescent light emitting element 30 toward the collimating optical system 40 together with the fluorescence. Accordingly, white light is emitted from the fluorescent light emitting element 30 toward the collimating optical system 40.

  The rotating plate 31 rotates at 7500 rpm during use. The diameter of the rotating plate 31 is 50 mm, and the optical axis of the blue light incident on the phosphor layer 32 is configured to be located about 22.5 mm away from the rotation center of the rotating plate 31. That is, on the rotating plate 31, the irradiation spot of blue light moves so as to draw a circle around the rotation axis O at a speed of about 18 m / sec.

  The collimating optical system 40 is disposed on the optical path of light (excitation light and fluorescence) between the fluorescent light emitting element 30 and the illumination optical system 100. The collimating optical system 40 includes a first lens 41 that suppresses the spread of light from the fluorescent light emitting element 30 and a second lens 42 that collimates the light incident from the first lens 41. The first lens 41 is made of, for example, a convex meniscus lens, and the second lens 42 is made of, for example, a convex lens. The collimating optical system 40 makes the light from the fluorescent light emitting element 30 enter the illumination optical system 100 in a substantially parallel state.

  The illumination optical system 100 is disposed between the light source device 1 and the color separation light guide optical system 200. The illumination optical system 100 includes a condenser lens 101, a rod integrator 102, and a collimating lens 103.

  The condensing lens 101 consists of a convex lens, for example. The condensing lens 101 is disposed on the light axis of the light incident from the collimating optical system 40 and condenses this light.

  The light transmitted through the condenser lens 101 enters one end side of the rod integrator 102. The rod integrator 102 is a prismatic optical member extending in the direction of the optical path. The light transmitted through the inside is mixed and the light transmitted through the condenser lens 101 is mixed to make the luminance distribution uniform. To do. The cross-sectional shape orthogonal to the optical path direction of the rod integrator 102 is substantially similar to the outer shape of the image forming region of the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B.

  Light emitted from the other end of the rod integrator 102 is collimated by the collimating lens 103 and emitted from the illumination optical system 100.

  The color separation light guide optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a reflection mirror 230, a reflection mirror 240, a reflection mirror 250, and a relay lens 260. The color separation light guide optical system 200 separates the light from the illumination optical system 100 into red light R, green light G, and blue light B, and illuminates each color light of red light R, green light G, and blue light B. The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B are guided.

  The dichroic mirror 210 and the dichroic mirror 220 are mirrors in which a wavelength selective transmission film that reflects light in a predetermined wavelength region and transmits light in another wavelength region is formed on a substrate. Specifically, the dichroic mirror 210 transmits a blue light component and reflects a red light component and a green light component. The dichroic mirror 220 reflects the green light component and transmits the red light component.

  The reflection mirror 230, the reflection mirror 240, and the reflection mirror 250 are mirrors that reflect incident light. Specifically, the reflection mirror 230 reflects the blue light component transmitted through the dichroic mirror 210. The reflection mirror 240 and the reflection mirror 250 reflect the red light component transmitted through the dichroic mirror 220.

  The blue light transmitted through the dichroic mirror 210 is reflected by the reflection mirror 230 and enters the image forming area of the liquid crystal light modulation device 400B for blue light. The green light reflected by the dichroic mirror 210 is further reflected by the dichroic mirror 220 and enters the image forming area of the liquid crystal light modulation device 400G for green light. The red light transmitted through the dichroic mirror 220 enters the image forming area of the liquid crystal light modulation device 400R for red light through the incident-side reflection mirror 240, the relay lens 260, and the emission-side reflection mirror 250.

  As the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B, commonly known devices can be used. For example, the liquid crystal element 410 and the polarization element 420 and the polarization element 430 that sandwich the liquid crystal element 410 And a light modulation device such as a transmissive liquid crystal light valve. For example, the polarizing element 420 and the polarizing element 430 have a configuration in which the transmission axes are orthogonal to each other (crossed Nicol arrangement).

  The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B modulate illumination light from the light source device 1, that is, incident color light, according to image information to form a color image. The light source device 1 is an illumination target. The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B perform light modulation of each incident color light.

  For example, the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B are transmissive liquid crystal light modulation devices in which liquid crystal is hermetically sealed in a pair of transparent substrates, and are provided with polysilicon TFTs as switching elements. The polarization direction of one type of linearly polarized light emitted from the incident side polarizing plate 420 is modulated according to the image information.

  The cross dichroic prism 500 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the emission side polarizing plate 430. The cross dichroic prism 500 has a substantially square shape in plan view in which four right angle prisms are bonded. A dielectric multilayer film is formed on the substantially X-shaped interface to which the right-angle prism is bonded. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, red light and blue light are bent, and the traveling direction of green light is aligned, so that three color lights are synthesized.

  The color image emitted from the cross dichroic prism 500 is enlarged and projected by the projection optical system 600, and an image is formed on the screen SCR.

  As described above, in the projector 1000 according to the present embodiment, a part of the blue laser light emitted as the excitation light from the excitation light source 10 is modulated by the liquid crystal light modulation device 400B, thereby forming a blue image. The That is, the screen SCR is irradiated with laser light emitted from the excitation light source 10 and transmitted through the phosphor layer 32.

  Here, the degree of danger of laser light will be described with reference to Table 1 standardized for “class” which is an index of the magnitude of laser light output and “danger assessment” in each class.

  As shown in Table 1, classes that serve as indicators of the output magnitude of laser light are classified into seven classes: class 1, class 1M, class 2, class 2M, class 3R, class 3B, and class 4.

  The output of laser light sources classified as class 1 is inherently safe in design.

  The output of the laser light source classified into class 1M is low output (wavelength of 302.5 to 4000 nm). It is safe under certain conditions including in-beam observation. Observing with optical means in the beam can be dangerous.

  The output of the laser light source classified as class 2 is visible light and low output (wavelength of 400 to 700 nm). The eyes are protected by the aversion reaction of the eyes, including the direct beam observation state.

  The output of the laser light source classified into class 2M is low output (wavelength of 400 to 700 nm) with visible light. The eyes are protected by normal eye disgust. Observing with optical means in the beam can be dangerous.

  The output of laser light sources classified as class 3R is 5 times or less (400 to 700 nm wavelength) of class 2 for visible light, and 5 times or less of class 1 (wavelength of 302.5 nm or more) for non-visible light. ) Output. Direct observation in the beam may be dangerous.

  The output of the laser light source classified into class 3B is an output of 0.5 W or less. Direct in-beam observation is dangerous. However, observing pulsed laser radiation that is not focused by diffuse reflection is not dangerous and can be observed safely under certain conditions.

  The output of the laser light source classified into class 4 is high output. May cause dangerous diffuse reflection. These can cause skin damage and can be a fire hazard.

  When the light source device 1 is operating normally, the intensity of the blue laser light projected onto the screen SCR maintains a safe intensity. However, it is assumed that the intensity of the blue laser light projected on the screen SCR exceeds a safe level for some reason. It is not preferable to irradiate the screen SCR with laser light having a high risk level such as class 4.

  Here, a case where an abnormality has occurred in the light source device 1 is considered. Here, a defect occurring in the phosphor layer 32 will be described as an example of an abnormality occurring in the light source device 1. As a defect that occurs in the phosphor layer 32, a part of the phosphor layer 32 is abnormally overheated due to a decrease in the rotational speed of the rotating plate 31 during operation of the light source device 1, and a part of the phosphor layer 32 is It can be altered. Similarly, a part of the phosphor layer 32 may be abnormally heated and a part of the phosphor layer 32 may disappear. Further, a part of the phosphor layer 32 may be lost. In the portion where the defect is generated in the phosphor layer 32, the component that is converted into fluorescence in the excitation light is reduced. Therefore, the fluorescence emitted from the portion where the defect is generated in the phosphor layer 32 becomes weak, and the phosphor layer 32 The intensity of the excitation light that passes through the portion where the defect has occurred increases. And there is a possibility that the intensity of the excitation light passing through the portion where the defect has occurred in the phosphor layer 32 exceeds a safe level.

  Therefore, the projector 1000 according to the present embodiment cancels the light shielding state of the fluorescence intensity detection device 50 as a detection device that detects the intensity of a part of the fluorescence emitted from the phosphor layer 32 and the liquid crystal light modulation device 400B. Whether or not based on the detection result by the fluorescence intensity detection device 50. As the fluorescence intensity detection device 50, for example, a photodiode is used. When the projector 1000 is activated, the control device 70 starts emitting excitation light from the excitation light source 10 while the liquid crystal light modulation device 400B is held in a light-shielded state. Thereafter, when the control device 70 determines that the intensity of the light detected by the fluorescence intensity detection device 50 is within a predetermined range, the control device 70 controls the drive device 60 to cancel the light blocking state of the liquid crystal light modulation device 400B. To do. As a result, the screen SCR is prevented from being irradiated with high-power laser light. In the present embodiment, the control device 70 is configured to suppress irradiation of the screen SCR with laser light having an output corresponding to class 4 shown in Table 1.

  The fluorescence intensity detection device 50 of the present embodiment is disposed in the vicinity of the fluorescent light bundle passing between the second lens 42 and the condenser lens 101, and the intensity of the fluorescent stray light emitted from the light source device 1. That is, the intensity of a part of the fluorescence emitted from the light source device 1 is detected.

  Next, the operation of the projector 1000 until the liquid crystal light modulation device 400B is released from the light shielding state will be described with reference to FIGS. It is assumed that a defect has occurred in a part of the phosphor layer 32 and the intensity of the fluorescence stray light detected by the fluorescence intensity detection device 50 varies with time as shown in FIG. I will explain.

  First, the liquid crystal light modulation device 400B is held in a light shielding state (step S1 shown in FIG. 4). Specifically, the control device 70 sends a control signal to the drive device 60 when the projector 1000 is activated. The driving device 60 that has received the control signal causes the liquid crystal light modulation device 400B to be in a light shielding state, and maintains the light shielding state of the liquid crystal light modulation device 400B. However, if the liquid crystal light modulation device 400B is in the light shielding state when the driving device 60 is not operating, the operation for bringing the liquid crystal light modulation device 400B into the light shielding state is unnecessary.

  Next, the fluorescent light emitting element 30 is rotated (step S2 shown in FIG. 4).

  When the fluorescent light emitting element 30 rotates, the control device 70 determines whether or not the rotational speed of the fluorescent light emitting element 30 is equal to or higher than a predetermined rotational speed (step S3 shown in FIG. 4), and the rotational speed of the fluorescent light emitting element 30 is determined. Is greater than or equal to a predetermined number of revolutions, the excitation light source 10 is activated (step S4 shown in FIG. 4).

  Here, the predetermined rotational speed is a rotational speed at which the fluorescent light emitting element 30 can dissipate heat accumulated in the fluorescent light emitting element 30 by irradiation of excitation light. The predetermined number of rotations is set based on data such as the intensity of excitation light emitted from the excitation light source 10, the diameter of the rotating plate 31, and the thermal conductivity of the rotating plate 31. The predetermined rotational speed is set in consideration of a safety factor and the like. The predetermined number of revolutions is set to a sufficiently large value so that thermal energy that alters the phosphor layer 32 or melts the rotating plate 31 is not accumulated.

  On the other hand, when the rotational speed of the fluorescent light emitting element 30 is less than the predetermined rotational speed, the control device 70 outputs a stop signal to the motor 33 (step S5 shown in FIG. 4), and an error display is displayed (FIG. 4). Step S6). For example, the user recognizes that an abnormality has occurred in the projector 1000 by seeing that a warning lamp provided in the projector is lit.

  When the excitation light source 10 is activated, excitation light is emitted from the excitation light source 10, and the excitation light is collected on the phosphor layer 32 formed on the rotating plate 31. The irradiation spot of the excitation light moves so as to draw a circle around the rotation axis O by the rotation of the fluorescent light emitting element 30. In the present embodiment, the fluorescence intensity detection device 50 detects the intensity of the fluorescent stray light emitted from the light source device 1.

  FIG. 3 is a graph showing temporal changes in the intensity of the stray light of the fluorescence detected by the fluorescence intensity detection device 50 when a defect has occurred in a part of the phosphor layer 32. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the intensity of fluorescent stray light detected by the fluorescence intensity detection device 50. Further, t1 is a time required for the rotation plate 31 to make one rotation.

  In the period in which the excitation light is irradiated to the region of the phosphor layer 32 where no defect has occurred, the intensity of the fluorescence stray light detected by the fluorescence intensity detection device 50 is K0. However, the intensity of the fluorescence emitted from the light source device 1 decreases during the period in which the excitation light is irradiated on the region where the defect occurs in the phosphor layer 32. Therefore, as shown in FIG. 3, the intensity of the fluorescence stray light detected by the fluorescence intensity detection device 50 also decreases during that period.

  In step S <b> 11, the control device 70 detects the intensity of the fluorescence stray light by the fluorescence intensity detection device 50 at least while the irradiation spot of the excitation light is located in the fluorescence emission region. In the present embodiment, the period during which the excitation light irradiation spot is located in the fluorescence emission region is t1. Further, the control device 70 determines whether or not the intensity of the fluorescent stray light detected by the fluorescence intensity detection device 50 is always equal to or higher than the predetermined intensity K1 while the rotating plate 31 rotates once. The predetermined intensity K1 is a value set to determine whether or not excitation light having an intensity exceeding a safe level is projected onto the screen SCR. The predetermined intensity K1 is appropriately set based on the location where the fluorescence intensity detection device 50 is disposed, the light emission efficiency of the phosphor layer 32, and the like. If it is determined that the intensity of the fluorescent stray light detected by the fluorescence intensity detection device 50 is always equal to or greater than the predetermined intensity K1 during one rotation of the rotating plate 31, a defect occurs in the phosphor layer 32. Even if it is, it is determined that excitation light having an intensity exceeding a safe level is not projected onto the screen SCR. Therefore, in this case, the control device 70 performs control to cancel the light blocking state of the liquid crystal light modulation device 400B (step S12 shown in FIG. 5). Specifically, the control device 70 sends a control signal to the drive device 60. Receiving the control signal, the driving device 60 cancels the light shielding state of the liquid crystal light modulation device 400B. The liquid crystal light modulation device 400B released from the light shielding state starts modulation of the light emitted from the light source device 1. Thereby, a desired color image is formed on the screen SCR.

  On the other hand, if the intensity of the stray light of the fluorescence detected by the fluorescence intensity detection device 50 is temporarily or always during the period of one rotation of the rotating plate 31, the excitation with an intensity exceeding a safe level is less than the predetermined intensity K1. It is determined that light is projected onto the screen SCR. Therefore, in step S13, the control device 70 outputs a stop signal to the excitation light source 10 while maintaining the light shielding state of the liquid crystal light modulation device 400B. When a stop signal is input from the control device 70 to the excitation light source 10, emission of excitation light from the excitation light source 10 stops.

  Further, the control device 70 outputs a stop signal to the motor 33. When a stop signal is input to the motor 33 from the control device 70, the rotation of the fluorescent light emitting element 30 stops (step S14 shown in FIG. 5).

  Then, an error is displayed (step S15 shown in FIG. 5). For example, the user recognizes that an abnormality has occurred in the projector 1000 by seeing that a warning lamp provided in the projector is lit.

  Thus, according to the projector 1000 of the present embodiment, when there is a possibility that excitation light having an intensity exceeding a safe level is projected onto the screen SCR, the light shielding state of the liquid crystal light modulation device 400B is maintained. The excitation light can be stopped by the liquid crystal light modulation device 400B. Therefore, it is possible to prevent the high output light from being projected onto the screen SCR and to ensure safety.

  Further, according to this configuration, the heat generated in the rotating plate 31 by the irradiation of the excitation light emitted from the excitation light source 10 can be dissipated in a wide region along the rotation direction of the rotating plate 31. For this reason, it can suppress that the rotating plate 31 melt | dissolves by irradiation of the excitation light inject | emitted from the excitation light source 10. FIG.

  Further, according to this configuration, since the laser light source is used as the excitation light source 10, the light condensing property is high as compared with, for example, a halogen lamp or an ultrahigh pressure mercury lamp. Therefore, high-power light is collected on the rotating plate 31. At this time, the portion of the rotating plate 31 where the laser beam is condensed melts and the hole is easily opened. Therefore, in such a configuration, the effect of the present invention that suppresses the irradiation of the high-power light onto the screen SCR and ensures safety becomes remarkable.

  In the present embodiment, the fluorescence intensity detection device 50 has been described by taking an example in which the fluorescence intensity detection device 50 is disposed in the vicinity of the fluorescent light bundle passing between the second lens 42 and the condenser lens 101. However, the present invention is not limited thereto. Absent. For example, the fluorescence intensity detection device 50 may be disposed in the vicinity of a fluorescent light bundle passing between the collimating lens 103 and the dichroic mirror 210. In other words, the fluorescence intensity detection device 50 only needs to be disposed at a position where the intensity of the fluorescence stray light emitted from the phosphor layer 32 can be detected.

  The present invention is not limited to detecting the intensity of fluorescent stray light. For example, a polarization beam splitter is disposed in a part of the optical path of the fluorescence emitted from the phosphor layer 32, and the polarization component that does not pass through the incident-side polarizing plate 420 among the fluorescence is guided to the fluorescence intensity detection device 50. May be. According to this configuration, it is possible to detect the intensity of the polarization component that does not pass through the incident-side polarizing plate 420 in the fluorescence. In addition, the fluorescence intensity detection device 50 may be provided in a portion of the fluorescent light beam emitted from the phosphor layer 32 that does not enter the image forming region of the liquid crystal light modulation device. With either configuration, it is possible to detect the intensity of a part of the fluorescence emitted from the phosphor layer 32.

  Moreover, in the light source device 1 of this embodiment, the light source which inject | emits a laser beam was used as a light source, However, It is not restricted to this. For example, a light source that emits light other than laser light may be used as the light source.

  In the light source device 1 of the present embodiment, the rotating plate is used as the substrate on which the phosphor layer is formed. However, the present invention is not limited to this. For example, a substrate that can vibrate in a direction crossing the direction in which excitation light is incident may be used as the substrate on which the phosphor layer is formed. That is, the substrate on which the phosphor layer is formed only needs to be movable in a direction intersecting the direction in which the excitation light is incident.

  In the projector 1000 of this embodiment, three liquid crystal light modulation devices are used as the liquid crystal light modulation device, but the present invention is not limited to this. The present invention can also be applied to a projector using one, two, four or more liquid crystal light modulation devices. Regardless of the number of liquid crystal light modulation devices, it is determined based on the detection result by the fluorescence intensity detection device 50 whether or not the light shielding state of the liquid crystal light modulation device to which the excitation light transmitted through the phosphor layer 32 is incident is released. As a result, it is possible to prevent the high output light from being projected onto the screen SCR and to ensure safety.

  In the projector 1000 of the present embodiment, a transmissive projector is used, but the present invention is not limited to this. For example, a reflective projector may be used. Here, “transmission type” means that the light modulation device as the light modulation means is a type that transmits light, such as a transmission type liquid crystal display device. The “reflective type” means that a light modulation device as a light modulation unit, such as a reflection type liquid crystal display device, reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(Second Embodiment)
FIG. 6 is a schematic diagram showing a projector 2000 according to the second embodiment of the present invention.
As shown in FIG. 6, the projector 2000 according to the present embodiment includes two light source devices (a first light source device 2 that emits red light R and green light G, and a second light source device 3 that emits blue light B). ), Two illumination optical systems (first illumination optical system 100A, second illumination optical system 100B), color separation light guide optical system instead of color separation light guide optical system 200 The projector 201 is different from the projector 1000 according to the first embodiment in that the system 201 is provided and the excitation light intensity detector 51 is provided instead of the fluorescence intensity detector 50. Since the other points are the same as the above-described configuration, the same elements as those in FIG.

  As shown in FIG. 6, the projector 2000 includes a first light source device 2, a second light source device 3, a first illumination optical system 100A, a second illumination optical system 100B, and color separation light guide optics. A system 201, a liquid crystal light modulation device 400R as a light modulation device, a liquid crystal light modulation device 400G, a liquid crystal light modulation device 400B, a cross dichroic prism 500, a projection optical system 600, an excitation light intensity detection device 51, and a drive device 60 and a control device 70.

  The light source device 1 described in the first embodiment is configured to emit not only fluorescence including red light R and green light G but also part of excitation light (blue light B). In contrast, the first light source device 2 according to the present embodiment emits fluorescence including red light R and green light G, but does not emit excitation light (blue light B).

  In the projector 2000 of this embodiment, all of the blue light emitted from the excitation light source 10 is used as excitation light for the phosphor layer 32. Blue light used as illumination light of the liquid crystal light modulation device 400B is emitted from a second light source device 3 provided separately from the first light source device 2.

  The first illumination optical system 100 </ b> A is disposed between the first light source device 2 and the color separation light guide optical system 201. The configuration of the first illumination optical system 100A is the same as the configuration of the illumination optical system 100 according to the first embodiment.

  On the other hand, the second light source device 3 includes a light source 80 and a collimating optical system 40. The light source 80 is an LED (Light Emitting Diode) light source that emits blue light B. The collimating optical system 40 includes a first lens 41 on which the blue light B is incident and a second lens 42 that collimates the laser light transmitted through the first lens 41. The collimating optical system 40 collimates the blue light B emitted from the light source 80.

  The second illumination optical system 100B is disposed between the second light source device 3 and the color separation light guide optical system 201. The configuration of the second illumination optical system 100B is the same as the configuration of the illumination optical system 100 according to the first embodiment.

  The fluorescence RG emitted from the first light source device 2 is guided to the color separation light guide optical system 201 by the first illumination optical system 100A.

  The light (blue light B) emitted from the second light source device 3 is guided to the color separation light guide optical system 201 by the second illumination optical system 100B.

  The color separation light guide optical system 201 includes a dichroic mirror 211, a reflection mirror 221, a reflection mirror 231, and a reflection mirror 251.

  The fluorescence RG emitted from the first illumination optical system 100A enters the dichroic mirror 211. The dichroic mirror 211 is a mirror in which a wavelength selective transmission film that reflects light in a predetermined wavelength region and transmits light in another wavelength region is formed on a substrate. Specifically, the dichroic mirror 211 reflects a red light component and transmits light having a shorter wavelength than red light such as green light and blue light.

  The green light G contained in the fluorescent light RG passes through the dichroic mirror 211, is reflected by the reflection mirror 221, and enters the image forming area of the liquid crystal light modulation device 400G for green light. The red light R included in the fluorescence RG is reflected by the dichroic mirror 211, reflected by the reflecting mirror 231, and enters the image forming area of the liquid crystal light modulation device 400R for red light.

  On the other hand, the light (blue light B) emitted from the second illumination optical system 100B is reflected by the reflection mirror 251 and enters the image forming area of the blue liquid crystal light modulation device 400B.

  The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B modulate illumination light from the first light source device 2 and the second light source device 3, that is, incident color light, according to image information. To form a color image. The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B perform light modulation of each incident color light.

  In the projector 2000, since all of the excitation light emitted from the excitation light source 10 is converted into fluorescence by the phosphor layer 32, the excitation light is projected onto the screen SCR if the first light source device 2 is operating normally. It will never be done.

  Here, as in the first embodiment, a case where a defect has occurred in the phosphor layer 32 is considered. In the portion where the phosphor layer 32 is defective, a component of the excitation light that is not converted to fluorescence is generated. Components of the excitation light that have not been converted to fluorescence pass through the phosphor layer 32 and enter the dichroic mirror 211 together with the fluorescence RG. There is a possibility that the intensity of the excitation light incident on the dichroic mirror 211 exceeds a safe level. The excitation light that has entered the dichroic mirror 211 passes through the dichroic mirror 211, is reflected by the reflection mirror 221, and enters the image forming region of the liquid crystal light modulation device 400G for green light.

  Therefore, in the projector 2000 according to the present embodiment, excessively strong excitation light is incident when a defect is generated in the phosphor layer 32 in order to suppress excessively strong excitation light from being applied to the screen SCR. Control of the operation of the liquid crystal light modulation device 400G that may possibly occur is performed based on the detection result of the detection device. The projector 2000 detects whether or not the light blocking state of the excitation light intensity detection device 51 as a detection device for detecting the intensity of the excitation light emitted from the phosphor layer 32 and the liquid crystal light modulation device 400G is canceled. And a control device 71 that makes a determination based on the detection result by the device 51. As the excitation light intensity detection device 51, for example, a photodiode is used. When the projector 2000 is activated, the control device 71 starts emitting excitation light from the excitation light source 10 in a state where the liquid crystal light modulation device 400G is held in a light shielding state. Thereafter, when the control device 71 determines that the light intensity detected by the excitation light intensity detection device 51 is within a predetermined range, the control device 71 causes the drive device 60 to release the light blocking state of the liquid crystal light modulation device 400G. Control. The liquid crystal light modulation device 400G from which the light shielding state has been released starts modulating the light emitted from the first light source device 2. As a result, the screen SCR is prevented from being irradiated with high-power laser light. Also in the present embodiment, the control device 71 is configured to suppress the screen SCR from being irradiated with laser light having an output corresponding to class 4 shown in Table 1.

  The excitation light intensity detection device 51 of this embodiment is disposed in the vicinity of the light beam bundle between the dichroic mirror 211 and the reflection mirror 221, and the stray light of the excitation light emitted from the first light source device 2. The intensity, that is, the intensity of a part of the excitation light emitted from the first light source device 2 is detected.

  Next, the operation of the projector 2000 until the liquid crystal light modulation device 400G is released from the light shielding state will be described with reference to FIGS. Note that a case where a defect has occurred in a part of the phosphor layer 32 and the intensity of the stray light of the excitation light detected by the excitation light intensity detection device 51 fluctuates with time as shown in FIG. An explanation will be given.

  Note that the operation of the projector 2000 from the time when the liquid crystal light modulation device 400G is put into a light-shielding state (corresponding to step S1 shown in FIG. 4) until the excitation light source 10 is activated (corresponding to step S4 shown in FIG. 4) is described above. Since this is the same as the operation of the projector 1000 according to the first embodiment, the description is omitted.

  When the excitation light source 10 is activated, excitation light is emitted from the excitation light source 10, and the excitation light is collected on the phosphor layer 32 formed on the rotating plate 31. The irradiation spot of the excitation light moves so as to draw a circle around the rotation axis O by the rotation of the fluorescent light emitting element 30. In the present embodiment, the excitation light intensity detection device 51 detects the intensity of stray light of the excitation light emitted from the first light source device 2.

  FIG. 7 is a graph showing temporal changes in the intensity of stray light of excitation light detected by the excitation light intensity detection device 51 when a defect is generated in a part of the phosphor layer 32. In FIG. 7, the horizontal axis represents time, and the vertical axis represents stray light intensity of the excitation light detected by the excitation light intensity detection device 51. Further, t1 is a time required for the rotation plate 31 to make one rotation.

  In a period in which excitation light is irradiated to a region where no defect has occurred in the phosphor layer 32, the intensity of the stray light of the excitation light detected by the excitation light intensity detection device 51 is R0. In the present embodiment, the intensity R0 is zero. On the other hand, the intensity of the excitation light emitted from the first light source device 2 increases during the period in which the region where the defect is generated in the phosphor layer 32 is irradiated with the excitation light. During that period, the stray light intensity of the excitation light detected by the excitation light intensity detection device 51 also increases as shown in FIG.

  In step S21, the control device 71 detects the intensity of the stray light of the excitation light by the excitation light intensity detection device 51 at least while the irradiation spot of the excitation light is located in the fluorescent light emission region. In the present embodiment, the period during which the excitation light irradiation spot is located in the fluorescence emission region is t1. Further, the control device 71 determines whether or not the intensity of the stray light of the excitation light detected by the excitation light intensity detection device 51 is always equal to or less than the predetermined intensity R1 while the rotating plate 31 rotates once. The predetermined intensity R1 is a value set to determine whether excitation light having an intensity exceeding a safe level is projected onto the screen SCR. The predetermined intensity R1 is appropriately set based on the location where the excitation light intensity detection device 51 is disposed, the output of the excitation light source 10, and the like. When it is determined that the stray light intensity of the excitation light detected by the excitation light intensity detection device 51 is always equal to or less than the predetermined intensity R1 during one rotation of the rotating plate 31, there is a defect in the phosphor layer 32. Even if it is generated, it is determined that excitation light having an intensity exceeding a safe level is not projected onto the screen SCR. Therefore, in this case, the control device 71 performs control to cancel the light blocking state of the liquid crystal light modulation device 400G (step S22 shown in FIG. 8). Specifically, the control device 71 sends a control signal to the drive device 60. Upon receiving the control signal, the driving device 60 cancels the light shielding state of the liquid crystal light modulation device 400G. The liquid crystal light modulation device 400G from which the light shielding state has been released starts modulating the light emitted from the first light source device 2. Thereby, a desired color image is formed on the screen SCR.

  On the other hand, when the intensity of the stray light of the excitation light detected by the excitation light intensity detection device 51 is temporarily or always during the period of one rotation of the rotating plate 31, the intensity exceeding the safe level is greater than the predetermined intensity R1. Is determined to be projected onto the screen SCR. Therefore, in step S23, the control device 71 outputs a stop signal to the excitation light source 10 while maintaining the light shielding state of the liquid crystal light modulation device 400G. When a stop signal is input from the control device 70 to the excitation light source 10, emission of excitation light from the excitation light source 10 stops.

  In addition, the control device 71 outputs a stop signal to the motor 33. When a stop signal is input to the motor 33 from the control device 71, the rotation of the fluorescent light emitting element 30 stops (step S24 shown in FIG. 8).

  Then, an error is displayed (step S25 shown in FIG. 8). For example, the user recognizes that an abnormality has occurred in the projector 2000 by seeing that a warning lamp provided in the projector is lit. Alternatively, the second light source device 3 may be operated to display an error display on the screen SCR with blue light.

  As described above, in the projector 2000 according to the present embodiment, when there is a possibility that excitation light having an intensity exceeding a safe level is projected onto the screen SCR, the liquid crystal light modulation device 400G in which the excitation light may enter may be used. The light shielding state is maintained. Therefore, similarly to the projector 1000 according to the first embodiment, it is possible to prevent high-power light from being projected onto the screen SCR and to ensure safety.

  By the way, when the excitation light intensity detection device is disposed on the optical path of the portion of the light beam emitted from the light source device that is incident on the image formation region of the liquid crystal light modulation device, it should be incident on the image formation region of the liquid crystal light modulation device. A part of the light beam is blocked by the excitation light intensity detector. In this case, at least a part of the light emitted from the light source device cannot be used as illumination light. On the other hand, according to the present embodiment, the excitation light intensity detection device 51 modulates the liquid crystal light among the light beams emitted from the first light source device 2 between the first light source device 2 and the liquid crystal light modulation device 400G. Since it is arranged in an area that does not overlap with the part that should enter the image forming area of the apparatus, it is possible to efficiently use the light emitted from the first light source device 2 as illumination light.

  In the first embodiment, a configuration including the fluorescence intensity detection device 50 as a detection device will be described as an example. In the second embodiment, a configuration including the excitation light intensity detection device 51 as a detection device. Although described as an example, it is not limited to this. For example, both the fluorescence intensity detection apparatus 50 and the excitation light intensity detection apparatus 51 may be provided as the detection apparatus.

  According to this configuration, when at least one of the intensity of the fluorescent stray light and the intensity of the stray light of the excitation light indicates that the excitation light having an intensity exceeding a safe level may be projected onto the screen SCR. It is sufficient that the light shielding state of the liquid crystal light modulation device is maintained. According to this configuration, safety can be further enhanced.

(Third embodiment)
FIG. 9 is a schematic diagram showing a projector 3000 according to the third embodiment of the present invention.
As shown in FIG. 9, the projector 3000 according to the present embodiment includes a light source device 4 instead of the light source device 1 and the illumination optical system 100 according to the first embodiment described above, and the first embodiment described above. Instead of the color separation light guide optical system 200, the liquid crystal light modulation device 400R as the light modulation device, the liquid crystal light modulation device 400G, the liquid crystal light modulation device 400B, and the cross dichroic prism 500, the micromirror type light modulation device 5 is used. The first described above in that it includes the projection optical system 6 instead of the projection optical system 600, and includes both the fluorescence intensity detection device 50 and the excitation light intensity detection device 51. This is different from the projector 1000 according to the embodiment. Since the other points are the same as the above-described configuration, the same elements as those in FIG.

  As shown in FIG. 9, the projector 3000 includes a light source device 4, a light modulation device 5, a projection optical system 6, a fluorescence intensity detection device 50, an excitation light intensity detection device 51, a drive device 62, and a control device. 72.

  The light source device 4 includes an excitation light source 10C, a light emitting element 20C, and a fluorescent light emitting element 30C. The excitation light source 10C emits blue light, the light emitting element 20C emits red light, and the fluorescent light emitting element 30C emits green light. Then, the light source device 4 sequentially emits blue light (excitation light), green light (fluorescence), and red light.

  The excitation light source 10C is a laser light source that emits blue laser light (emission intensity peak: about 445 nm). On the optical path of the excitation light emitted from the excitation light source 10C, the first dichroic mirror 90, the first condenser lens 91, the fluorescent light emitting element 30C, the first reflection mirror 92, the second reflection mirror 94, and the second dichroic mirror 95 are provided. , And the second condenser lens 93 are arranged in this order. The excitation light source 10C may be an excitation light source that emits colored light having a peak wavelength other than 445 nm as long as it is light having a wavelength that can excite a fluorescent material to be described later.

  The light emitting element 20C is a red light emitting diode that emits red light (emission intensity peak: about 620 nm). A first dichroic mirror 90, a second dichroic mirror 95, and a second condenser lens 93 are arranged in this order on the optical path of red light emitted from the light emitting element 20C.

  The first dichroic mirror 90 is disposed so as to intersect with each of the optical axis of the excitation light source 10C and the optical axis of the light emitting element 20C at an angle of approximately 45 °. The first dichroic mirror 90 transmits the excitation light emitted from the excitation light source 10C and the red light emitted from the light emitting element 20C. The first dichroic mirror 90 reflects the fluorescence (green light) emitted from the phosphor layer 32C by the irradiation of excitation light (blue light).

  The first condenser lens 91 causes the excitation light transmitted through the first dichroic mirror 90 to enter the phosphor layer 32C in a substantially condensed state and makes the green light emitted from the phosphor layer 32C substantially parallel.

FIG. 10 is a schematic diagram of a fluorescent light emitting device 30C according to the present embodiment. FIG. 10A is a plan view of the fluorescent light emitting element 30C, and FIG. 10B is a cross-sectional view taken along line AA ′ of the fluorescent light emitting element 30C.
As shown in FIG. 10, the fluorescent light emitting element 30 includes a rotating plate 31C that is driven to rotate about a rotation axis O by a motor 33C, and a metal member 34C that is formed on a main surface on which excitation light of the rotating plate 31C is incident. And a phosphor layer 32C as a fluorescence emission region formed on the metal member 34C along the outer periphery of the rotating plate 31C. The rotating plate 31C is made of a material that transmits excitation light, such as polycarbonate. For the metal member 34C, a metal material having a high thermal conductivity such as aluminum can be used.

  The fluorescent light emitting element 30C can be virtually divided into a plurality of fan-shaped regions. The plurality of regions include a first region AR1, a second region AR2, and a third region AR3. As shown in FIG. 10A, the fluorescent light emitting element 30C is divided into the first area AR1, the second area AR2, and the third area AR3 in this order in the clockwise direction along the circumferential direction. Can do.

  On the main surface of the fluorescent light emitting element 30C, a phosphor layer 32C is formed in the first region AR1 along the outer periphery of the fluorescent light emitting element 30C. A diffusion region 35C for diffusing excitation light is formed in the third region AR3 of the fluorescent light emitting element 30C. The excitation light passes through the third area AR3. The diffusion region 35C is formed along the circumferential direction of the rotating plate 31C.

  The excitation light irradiation spot Q in the fluorescent light emitting element 30C moves around the rotation axis O according to the rotation of the fluorescent light emitting element 30C. Then, in time sequence, they are located in the first area AR1, the second area AR2, and the third area AR3. FIG. 10A shows a state where the excitation light irradiation position Q is located in the first region AR1.

The phosphor layer 32C is made of, for example, a layer containing (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, which is a YAG phosphor. The phosphor layer 32C converts substantially all of the laser light (blue light) as excitation light emitted from the excitation light source 10 into green light (emission intensity peak: about 550 nm).

  In the fluorescent light emitting element 30C, a region where the phosphor layer 32C is formed is a reflection surface. In the present embodiment, the phosphor layer 32C is provided on the metal member 34C that is a reflective surface. Therefore, the fluorescence emitted from the phosphor layer 32 </ b> C is reflected by the reflecting surface toward the first condenser lens 91.

  In the projector 3000 of the present embodiment, the timing at which excitation light is emitted from the excitation light source 10C and the timing at which red light is emitted from the light emitting element 20C are sequentially timed by the control device 72 according to the rotation of the fluorescent light emitting element 30C. Adjust to.

  In the present embodiment, as shown in FIG. 10A, when the excitation light irradiation spot Q is located in the first region AR1 and the third region AR3, the excitation light is emitted from the excitation light source 10C. Red light is not emitted from the light emitting element 20C. Further, when the excitation light irradiation spot Q is located in the second area AR2, red light is emitted from the light emitting element 20C, but excitation light is not emitted from the excitation light source 10C.

  With such a configuration, blue light, green light, and red light are sequentially emitted from the light source device 4 in this order in accordance with the rotation of the fluorescent light emitting element 30C.

  Returning to FIG. 9, the first reflection mirror 92 reflects the excitation light (blue light) transmitted through the third region AR <b> 3 of the fluorescent light emitting element 30 </ b> C toward the second reflection mirror 94. The second reflection mirror 94 reflects the excitation light (blue light) reflected by the first reflection mirror 92 toward the second dichroic mirror 95.

  The first dichroic mirror 90 emits green light emitted from the phosphor layer 32C formed in the first region AR1 of the fluorescent light emitting element 30C and collimated by the first condenser lens 91 to the second dichroic mirror 95. Reflect toward you.

  The red light emitted from the light emitting element 20 </ b> C passes through the first dichroic mirror 90 and travels toward the second dichroic mirror 95.

  The second dichroic mirror 95 transmits the green light reflected by the first dichroic mirror 90 and the red light emitted from the light emitting element 20 </ b> C toward the second condenser lens 93 and reflects by the second reflecting mirror 94. The excited excitation light (blue light) is reflected toward the second condenser lens 93.

  The second condenser lens 93 substantially collects the excitation light (blue light) reflected by the second dichroic mirror 95, the green light transmitted through the second dichroic mirror 95, and the red light transmitted through the second dichroic mirror 95. The light is incident on the light modulation device 5.

  The light modulation device 5 is a micromirror type light modulation device. For example, DMD (digital micromirror device) (trademark of TI) is used as the light modulation device 5. The projector 3000 employs a DLP (Digital Light Processing) method using DMD and dedicated signal processing technology. The DMD 5 has a plurality of micromirrors arranged in a matrix. The DMD 5 displays an image by switching the reflection direction of incident light between the direction of the projection optical system 6 and the direction of a light-absorbing plate (not shown) by switching the tilt directions of the plurality of micromirrors. The DMD 5 sequentially modulates green light, red light, and blue light emitted from the light source device 4 and sequentially projects the green image, red image, and blue image on the screen SCR via the projection optical system 6. When the light source device 4 is operating normally, excitation light having an intensity exceeding a safe level is not projected onto the screen SCR.

  Here, as in the first embodiment, a case where a defect has occurred in the phosphor layer 32C is considered. In the portion where the defect has occurred in the phosphor layer 32C, the component of the excitation light that is converted to fluorescence is reduced, and the component of the excitation light that is not converted to fluorescence is incident on the metal member 34C. When the intensity of the excitation light incident on the metal member 34C is extremely high, a hole is opened in the metal member 34C, and a part of the excitation light passes through the hole. When the excitation light passes through the third region AR3 of the fluorescent light emitting element 30C, the excitation light is diffused by the diffusion region 35C, so that the intensity of the blue light projected on the screen SCR is below a safe level. However, when the excitation light passes through the hole opened in the metal member 34C, the intensity of the blue light projected on the screen SCR may exceed a safe level.

  Further, since the fluorescence emitted from the portion where the defect has occurred in the phosphor layer 32C becomes weak, the conversion efficiency of the excitation light into the fluorescence at the portion where the defect has occurred in the phosphor layer 32C is lowered.

  Therefore, the projector 3000 according to the present embodiment includes a fluorescence intensity detection device 50 that detects the intensity of the fluorescence emitted from the phosphor layer 32C, and the intensity of excitation light emitted from the excitation light source 10C and transmitted through the fluorescence light emitting element 30C. Excitation light intensity detecting device 51 for detecting the light intensity, and a control device for determining whether or not to cancel the light blocking state of the light modulation device 5 based on the detection result by the fluorescence intensity detection device 50 and the detection result by the excitation light intensity detection device 51 72. When the projector 3000 is activated, the control device 72 starts emitting the excitation light from the excitation light source 10C in a state where the light modulation device 5 is held in the light shielding state. Thereafter, the control device 72 converts the excitation light into fluorescence by the phosphor layer 32C based on the light intensity detected by the fluorescence intensity detection device 50 and the light intensity detected by the excitation light intensity detection device 51. Is estimated. When it is determined that the estimated conversion efficiency is within a predetermined range, the control device 72 controls the drive device 62 so as to cancel the light blocking state of the light modulation device 5. As a result, the screen SCR is prevented from being irradiated with high-power laser light. In the present embodiment, the control device 72 is configured to suppress the screen SCR from being irradiated with laser light having an output corresponding to class 4 shown in Table 1.

  Here, the “light shielding state” of the light modulation device 5 refers to the inclination direction of the plurality of micromirrors so that the incident light on the DMD 5 is reflected in a direction other than the projection optical system 6, for example, in the direction of a light-absorbing plate (not shown). It is in a set state.

  The fluorescence intensity detection device 50 according to the present embodiment is arranged in the vicinity of the fluorescent light bundle passing between the second dichroic mirror 95 and the second condenser lens 93, and the fluorescence emitted from the phosphor layer 32C. The intensity of the stray light, that is, the intensity of a part of the fluorescence emitted from the phosphor layer 32C is detected.

  The excitation light intensity detection device 51 of the present embodiment is disposed in the vicinity of the beam bundle of excitation light that passes between the first reflection mirror 92 and the second reflection mirror 94, is emitted from the excitation light source 10C, and is fluorescent. The intensity of the stray light of the excitation light transmitted through the light emitting element 30C, that is, a part of the excitation light emitted from the excitation light source 10C is detected.

  In this embodiment, since the value obtained by dividing the intensity of the fluorescent stray light by the intensity of the stray light of the excitation light is used as the estimated value of the conversion efficiency, the estimated conversion efficiency is different from the true conversion efficiency. However, in the following description, the estimated conversion efficiency is simply referred to as conversion efficiency for convenience.

  Next, the operation of the projector 3000 until the light blocking state of the light modulation device 5 is canceled will be described with reference to FIGS. 11 and 12. A description will be given assuming that a defect has occurred in a part of the phosphor layer 32C and the conversion efficiency fluctuates with time as shown in FIG.

  The operation of the projector 3000 from the time when the light modulation device 5 is put into the light-shielding state (corresponding to step S1 shown in FIG. 4) to the time when the excitation light source 10C is activated (corresponding to step S4 shown in FIG. 4) has been described above. Since the operation is the same as that of the projector 1000 according to the first embodiment, a description thereof will be omitted. Again, if the light modulation device 5 is in the light shielding state with the drive device 62 not operating, the step of bringing the light modulation device 5 into the light shielding state is unnecessary.

  When the excitation light source 10C is activated, excitation light is emitted from the excitation light source 10C, and the excitation light is collected on the rotating plate 31C. The irradiation spot Q of the excitation light moves so as to draw a circle around the rotation axis O by the rotation of the fluorescent light emitting element 30C. In the present embodiment, the fluorescence intensity detection device 50 detects the intensity of the stray light of fluorescence emitted from the phosphor layer 32C. Further, the excitation light intensity detection device 51 detects the intensity of the stray light of the excitation light emitted from the excitation light source 10C and transmitted through the fluorescent light emitting element 30C.

  FIG. 11 is a graph showing the change over time of the conversion efficiency estimated by the control device 72 when a defect occurs in a part of the phosphor layer 32C. In FIG. 11, the horizontal axis represents time, and the vertical axis represents conversion efficiency. Since fluorescence is not emitted from the fluorescent light emitting element 30C during the period when the irradiation spot Q of the excitation light is located in the second area AR2 and the third area, the conversion efficiency in that period is set to zero for convenience in FIG. is there. t1 is a time required for the phosphor layer 32C to make one rotation. In the present embodiment, since the central angle of the fan-shaped first region AR1 is 180 °, the time for which the irradiation spot Q of the excitation light is located in the first region AR1 is t1 / 2.

  In step S <b> 31, the control device 72 detects the intensity of the stray light of the fluorescence by the fluorescence intensity detection device 50 at least while the irradiation spot Q of the excitation light is located in the fluorescence emission region. The period during which the excitation light irradiation spot Q is located in the fluorescence emission region is t1 / 2 in this embodiment. Further, the control device 72 detects the intensity of stray light of the excitation light by the excitation light intensity detection device 51. Further, the control device 72 determines that the conversion efficiency of the excitation light into the fluorescence by the phosphor layer 32C is always equal to or higher than the predetermined conversion efficiency H1 while the excitation light irradiation spot Q is located in the fluorescence emission region. Judge whether or not. The predetermined conversion efficiency H1 is a value set to determine whether or not excitation light having an intensity exceeding a safe level is projected onto the screen SCR. The predetermined conversion efficiency H1 is appropriately set based on the location where the fluorescence intensity detection device 50 is disposed, the location where the excitation light intensity detection device 51 is disposed, the output of the excitation light source 10, or the like. While it is determined that the conversion efficiency is always equal to or higher than the predetermined conversion efficiency H1 while the excitation light irradiation spot Q is located in the fluorescence emission region, it is assumed that a defect has occurred in the phosphor layer 32. However, it is determined that excitation light having an intensity exceeding a safe level is not projected onto the screen SCR. Therefore, in this case, the control device 72 performs control to cancel the light blocking state of the light modulation device 5 (step S32 shown in FIG. 12). Specifically, the control device 72 sends a control signal to the drive device 62. Upon receiving the control signal, the driving device 62 cancels the light blocking state of the light modulation device 5. The light modulation device 5 released from the light shielding state starts modulation of the light emitted from the light source device 1. Thereby, a desired color image is formed on the screen SCR.

  On the other hand, if the conversion efficiency is smaller than the predetermined conversion efficiency H1 temporarily or always during the period in which the excitation light irradiation spot Q is located in the fluorescence emission region, the excitation light having an intensity exceeding a safe level is not detected. It is determined that the image is projected onto the screen SCR. Therefore, in step S33, the control device 72 outputs a stop signal to the excitation light source 10C while maintaining the light-shielding state of the light modulation device 5. When a stop signal is input from the control device 72 to the excitation light source 10, the emission of excitation light from the excitation light source 10 stops.

Further, the control device 72 outputs a stop signal to the motor 33. When a stop signal is input to the motor 33 from the control device 72, the rotation of the fluorescent light emitting element 30C stops (step S34 shown in FIG. 12).
Then, an error is displayed (step S35 shown in FIG. 12). For example, the user recognizes that an abnormality has occurred in the projector 3000 by seeing that a warning light provided in the projector is lit. Alternatively, the light emitting element 20C may be operated to display an error display on the screen SCR with red light.

  As described above, in the projector 3000 according to the present embodiment as well, when there is a possibility that excitation light having an intensity exceeding a safe level is projected onto the screen SCR, the light-shielding state of the light modulation device 5 is maintained, so that high output is achieved. It is possible to prevent the light from being projected onto the screen SCR and to ensure safety.

  Although the present invention has been described using the first to third embodiments, the present invention is not limited to the above-described embodiments. In Embodiment 2 described above, the excitation light intensity detection device 51 is provided as the detection device that detects the intensity of a part of the light emitted from the first light source device 2, but is not limited thereto. As the detection device, an element that can detect a change in the color of a part of the light emitted from the first light source device 2 may be used. When a defect has occurred in the phosphor layer 32, the excitation light (blue light) is mixed with the green light transmitted through the dichroic mirror 211, so that the color of the light transmitted through the dichroic mirror 211 changes. Therefore, even if an element capable of detecting a color change is used, it is possible to suppress the high output light from being projected onto the screen SCR and to ensure safety.

  Although Embodiment 1 thru | or Embodiment 3 demonstrated the case where a fluorescence light emitting element was a rotating plate rotated centering | focusing on a predetermined rotating shaft, it is not restricted to this. When a stationary fluorescent light emitting element that does not rotate is used, for example, when the cooling function of the light source device is lowered, a defect may occur in the phosphor layer due to heat. In addition, the phosphor layer may be lost. Even when a stationary fluorescent light-emitting element that does not rotate is used, according to the present invention, it is possible to prevent high-power light from being projected onto the screen SCR and to ensure safety. In this case, when determining whether or not the intensity of the fluorescent stray light is equal to or higher than the predetermined intensity K1, the length of time for detecting the intensity of the fluorescent stray light by the fluorescent intensity detection device 50 may be set as appropriate. Further, when determining whether the intensity of the stray light of the excitation light is equal to or less than the predetermined intensity R1, the length of time for detecting the intensity of the stray light of the excitation light by the excitation light intensity detection device 51 may be set as appropriate. . The same applies when estimating the conversion efficiency.

  In Embodiments 1 to 3, the rotating plate provided with the phosphor layer as the fluorescent light emitting region on the transparent substrate is used as the fluorescent light emitting element, but the present invention is not limited to this. The fluorescent light emitting element may be configured using a rotating plate in which phosphor particles are dispersed in a transparent substrate. The area | region where the fluorescent substance particle was disperse | distributed corresponds to the fluorescence light emission area | region among transparent substrates.

  The present invention is applicable not only when applied to a front projection type projector that projects from the side that observes the projected image, but also when applied to a rear projection type projector that projects from the side opposite to the side that observes the projected image. can do.

  In each of the above-described embodiments, the example in which the light source device of the present invention is applied to a projector has been described. For example, the light source device of the present invention can be applied to other optical devices (for example, automobile headlamps, lighting devices, etc.).

1, 2, 3, 4 ... Light source device, 10, 10C ... Excitation light source (light source) 31, 31C ... Rotating plate (substrate), 32, 32C ... Phosphor layer, 5 ... DMD (light modulation device), 6, 600 ... projection optical system, 50 ... fluorescence intensity detection device, 51 ... excitation light intensity detection device, 70, 71, 72 ... control device, 200 ... color separation light guide optical system, 221 ... reflection mirror (optical member), 400R, 400G, 400B ... Liquid crystal light modulation device (light modulation device), 1000, 2000, 3000 ... Projector, K1 ... First fluorescence intensity, K2 ... Second fluorescence intensity, R1 ... First excitation light intensity, R2 ... First Excitation light intensity of 2, H1 ... first conversion efficiency, H2 ... second conversion efficiency

Claims (9)

A light modulation device for modulating the excitation light;
A light source device that illuminates the light modulation device, comprising: an excitation light source that emits excitation light; and a fluorescence light-emitting element that has a fluorescence emission region that emits fluorescence when irradiated with the excitation light;
A detection device for detecting the intensity of a part of the light emitted from the light source device;
Whether the excitation light is emitted from the excitation light source while the light modulation device is held in a light-shielded state, and the light-shielding state of the light modulation device is released based on a detection result by the detection device. A control device for determining whether or not;
Including a projector. The detection device includes:
A fluorescence intensity detection device for detecting the intensity of a part of the fluorescence;
An excitation light intensity detection device for detecting the intensity of a part of the excitation light;
The projector according to claim 1, comprising at least one of the projectors. The detection device comprises the fluorescence intensity detection device,
The projector according to claim 2, wherein the control device releases the light blocking state of the light modulation device when the light intensity detected by the fluorescence intensity detection device is equal to or higher than a predetermined intensity. The detection device includes the excitation light intensity detection device,
3. The projector according to claim 2, wherein the control device releases the light blocking state of the light modulation device when the light intensity detected by the excitation light intensity detection device is less than a predetermined intensity. The detection device comprises the fluorescence intensity detection device and the excitation light intensity detection device,
The control device estimates the conversion efficiency of the excitation light into the fluorescence by the fluorescence emission region based on the detection result of the fluorescence intensity detection device and the detection result of the excitation light intensity detection device, and the estimated conversion efficiency The projector according to claim 2, wherein the light shielding state of the light modulation device is canceled when is equal to or greater than a predetermined value. The fluorescent light emitting element is a rotating plate that rotates around a predetermined rotation axis,
The projector according to claim 1, wherein the fluorescent light emitting region is provided along a rotation direction of the rotating plate. At least during the period when the irradiation spot of the excitation light is located in the fluorescence emission region, the detection device detects the intensity of a part of the light emitted from the light source device,
The projector according to claim 6, wherein the detection device determines whether or not to cancel a light blocking state of the light modulation device based on a detection result of the period.   The control device rotates the fluorescent light emitting element in a state where the light modulation device is held in a light shielding state, and the excitation light source emits the excitation when the rotational speed of the fluorescent light emitting element is equal to or higher than a predetermined rotational speed. The projector according to claim 6, wherein light is started to be emitted.   The projector according to claim 1, wherein the excitation light source emits laser light as the excitation light.

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