JP2010086000A - Projector - Google Patents

Abstract

A high-intensity laser beam is prevented from being inadvertently output to an observer.
A projector according to the present invention is a rear projection type projector including a light source that emits laser light and a scanner that scans the laser light on a screen. In the projector of the present invention, when a laser beam having an energy exceeding the exposure limit is output due to a failure of the light source 101 or the scanner 106, at least one optical member (lens optics) disposed on the optical path of the laser beam. The system 103, the scanner 106, the reflection mirror 109, the screen 120, etc.) are broken or altered, and the screen 120 does not emit light having energy exceeding the exposure limit.
[Selection] Figure 1

Description

  The present invention relates to a rear projection type projector that displays an image by scanning a laser beam on a screen.

2. Description of the Related Art Conventionally, a rear projection type projector that displays an image by scanning a laser beam on a screen has been proposed. In this projector, since the complete black can be displayed by stopping the supply of laser light, for example, display with higher contrast is possible compared to a projector using a liquid crystal light valve. Further, since the laser beam has high directivity, the projection optical system can be simplified. Therefore, the projector can be made small and simple. Furthermore, it can be easily colored by combining a plurality of laser beams such as red, green, and blue, and since the laser beam has high monochromaticity, color display with high color purity is possible.
By the way, when displaying an image using a laser beam, it is necessary to give sufficient consideration to safety so that the laser beam does not accidentally enter the observer's eyes. As a technique related to the safety mechanism of the projector, for example, there is one proposed in Patent Document 1.

JP 2002-6397 A

The technique proposed in Patent Document 1 is to cut off the laser output when the sensor senses that there is an object near the projection lens. However, in this method, it is conceivable that a high-intensity laser beam is emitted to the observer due to a sensor failure due to an unexpected external cause or a failure of the laser light output control circuit or the like.
The present invention has been made in view of such circumstances, and an object thereof is to provide a projector with higher safety.

  The projector of the present invention includes a light source that emits laser light and a scanner that scans the laser light on a screen, and laser light having energy exceeding the exposure limit is output due to failure of the light source or the scanner. Further, at least one optical member disposed on the optical path of the laser beam is damaged or altered, and the rear projection type projector is configured such that light having an energy exceeding the exposure release limit is not emitted from the screen. One of the optical members is a lens for collimation or beam shaping arranged on the optical path of the laser light between the scanner and the light source, and the scanner operates normally and the light source When the maximum exposure level allowed when there is an abnormality in the output intensity of the Over preparative or lenses for beam shaping is characterized by being composed of a material undergoes a phase transition by the heat of the laser light more than the first exposure release limit.

  According to this configuration, since the laser beam is shielded by directly damaging the optical member without complicated control as in the past, the safety of the display can be ensured regardless of an error due to a malfunction of the sensor. Can do.

  The scanner includes a movable plate that is rotatable about a predetermined rotation axis, a solid layer that is melted by the heat of the laser light that exceeds the first emission limit, and the movable plate that is disposed through the solid layer. It is desirable to include a light reflecting film formed on the surface.

  According to this configuration, even when high-intensity laser light is incident on the scanner, the solid layer is melted and the light reflection film is deformed to diffuse the incident high-intensity laser light. It is not observed by the observer as it is.

  The movable plate is preferably made of a material having an absorption wavelength range in the wavelength range of the laser beam.

  According to this configuration, even if the solid layer is melted and the light reflection film is peeled off, the laser light is absorbed by the light-absorbing movable plate exposed by the peeling, so that the high-intensity laser light remains as it is. Will not be observed.

  The projector of the present invention includes a light source that emits laser light and a scanner that scans the laser light on a screen, and laser light having energy exceeding the exposure limit is output due to failure of the light source or the scanner. Further, at least one optical member disposed on the optical path of the laser beam is damaged or altered, and the rear projection type projector is configured such that light having an energy exceeding the exposure release limit is not emitted from the screen. One of the optical members is a projection lens disposed on the optical path of the laser beam between the scanner and the screen, and the output intensity of the light source is normal and the scanner is stopped due to a failure. When the maximum exposure level allowed in the event of a failure is the second exposure release limit, the projection lens Characterized in that it is made of a material undergoes a phase transition with a laser beam of heat exceeds a second exposure release limit.

  According to this configuration, since the laser beam is shielded by directly damaging the optical member without complicated control as in the past, the safety of the display can be ensured regardless of an error due to a malfunction of the sensor. Can do.

  A reflecting mirror is provided on the optical path of the laser light between the scanner and the screen, and the reflecting mirror is melted by the heat of the laser light that exceeds the substrate and the second exposure limit. It is desirable to include a layer and a light reflecting film formed on the surface of the base material via the solid layer.

  According to this configuration, even if high-intensity laser light is incident on the reflection mirror, the solid layer is melted and the light reflection film is deformed to diffuse the incident high-intensity laser light. It is not observed by the observer as it is.

  The substrate is preferably made of a material having an absorption wavelength region in the wavelength region of the laser light.

  According to this configuration, even if the solid layer is melted and the light reflecting film is peeled off, the laser light is absorbed by the light-absorbing base material exposed by the peeling, so that the high-intensity laser light remains as it is. Will not be observed.

1 is a schematic diagram illustrating a configuration of a projector according to a first embodiment of the invention. Sectional drawing which shows the structure of a screen. Sectional drawing which shows the structure of a reflective mirror. Sectional drawing which shows the structure of a projection lens. FIG. 4 is a perspective view and a cross-sectional view illustrating a configuration of a scanner. The schematic diagram which shows the structure of the projector which concerns on 2nd Embodiment of this invention. FIG. 10 is a schematic diagram illustrating a configuration of a projector according to a third embodiment of the invention. Sectional drawing which shows the structure of a reflective mirror. Sectional drawing which shows the other structure of a reflective mirror.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the film thicknesses and dimensional ratios of the respective components are appropriately changed in order to make the drawings easy to see.

[First Embodiment]
FIG. 1 is a schematic diagram showing the configuration of the projector according to the first embodiment of the invention. The projector 100 according to this embodiment includes a light source 101 that emits laser light, a lens optical system 103 that includes a collimating optical system 104 and a beam shaping optical system 105, a scanner 106 that scans incident laser light in a two-dimensional direction, and scanning. A projection lens 108 that magnifies and projects the projected light and a reflection mirror 109 that reflects the projected light toward the screen 120 are roughly configured. In the projector 100, a light source 101, a lens optical system 103, a scanner 106, a projection lens 108, and a reflection mirror 109 are accommodated in a housing 110 provided with a screen 120, and laser light that travels inside the housing 110. The image is displayed by scanning on the screen 120.

Hereinafter, the configuration of the projector according to the present embodiment will be described together with its operation.
The light source 101 includes three types of laser diodes: a red laser diode 102R that emits red laser light, a green laser diode 102G that emits green laser light, and a blue laser diode 102B that emits blue laser light. These laser diodes 102 </ b> R, 102 </ b> G, 102 </ b> B output laser beams having an intensity that is modulated in accordance with an image signal from the control unit 107. Laser light emitted from the light source 101 enters a lens optical system 103 including a collimating optical system 104 and a beam shaping optical system 105. The lens optical system 103 shapes the laser light of each color emitted from the light source 101 into substantially parallel light with high directivity. The laser light of each color shaped by the lens optical system 103 enters the scanner 106. The scanner 106 is a device that forms an image by scanning incident laser light of each color in a two-dimensional direction. The operation of the scanner 106 is controlled by the control unit 107 according to the image signal of each color. The laser beams of the respective colors emitted from the scanner 106 are incident on a projection lens 108 that is an enlargement optical system, and after being enlarged here, are incident on a reflection mirror 109 provided facing the screen 120. The laser beams of the respective colors incident on the reflection mirror 109 are reflected toward the screen 120 and pass through the screen 120 to be visually recognized by an observer.

  By the way, since the projector 100 of the present embodiment performs display using laser light, there is some abnormality so that high-intensity laser light is not inadvertently output to the viewer due to a light source failure or a scanner failure. Sometimes, a mechanism (safety mechanism) that shields the laser beam from being output to the observer side is necessary. International safety standards for laser radiation are considered in IEC / TC 76. Currently, based on various experimental data, a standard document “IEC 60825 series” regarding laser safety has been issued. These consist of the parent standard “IEC 60825-1”, which defines common matters related to laser safety, and individual standards for optical communication equipment, medical equipment, high-power laser equipment, etc. New creations and revisions are being made as needed. In IEC (International Electrotechnical Commission) 60825-1, the rate of failure caused by laser radiation is obtained from past accidents and animal experiments, and the laser light intensity of 1/10 of the exposure amount at which this failure rate is 50% is maximized. It is called an allowable exposure (Maximum Permissible Exposure: MPE for short). MPE is determined by two axes of wavelength λ and exposure time t, and it can be said that it is safe if the radiation level is smaller than MPE. However, the degree of danger that lasers pose to humans varies depending on their wavelength, emission duration, energy amount, etc., and it is impossible to regard lasers as one group to which common safety standards can be applied. Therefore, the IEC groups lasers into several general classes, from intrinsically safe classes to dangerous classes for the eyes and skin, and the maximum exposure level allowed for each of them is the exposure limit. (Accessible Emission Limit: AEL for short).

(1) Class 1. A class in which AEL is set so as not to exceed MPE under any condition is referred to as class 1. This includes those that do not technically exceed MPE by design. For example, even if a laser light source exceeding the MPE is built in, the laser beam cannot be seen or touched structurally, or when the external structure for blocking the laser beam is removed, the human body If the structure is designed so as to be MPE or less by a mechanism capable of blocking all laser beams that may be touched, it is regarded as class 1.
(2) Class 1M. A class that does not cause a failure when viewed with the naked eye is called class 1M. The observation condition is that the observation is made with the naked eye at a distance of 10 cm from the light source (screen 120 in the present laser display).
(3) Class 2. This is a power level of 1 mW for which visible light with a wavelength λ = 400 to 700 nm is a target and danger is avoided by an aversion reaction of eyes (≦ 0.25 seconds).
(4) Class 2M. This is a class in which no failure occurs when viewed with the naked eye as in class 1M. It is a limited class that is safe due to an aversive reaction when observed with the naked eye (distance 10 cm).
(5) Class 3R. This is a class in which the power limit value is five times that of class 1 or class 2.
(6) Class 3B. It is dangerous to see or touch the direct light, and it is 0.5 W or less for CW light (continuous light).
(7) Class 4. Not only direct light but also scattered light is dangerous, and CW is a level exceeding 0.5 W.

In the projector according to the present embodiment, the class of laser light used for display is class 1 or class 1M. When laser light with energy exceeding this is output due to a failure, at least the laser light disposed on the optical path of the laser light is output. One optical member (in this embodiment, at least one optical member in the lens optical system 103, the scanner 106, the projection lens 108, the reflection mirror 109, and the screen 120) is broken (including deformation) or deteriorated. ing. Then, by diffusing or absorbing the laser light due to breakage or the like, the high-intensity light having energy exceeding the exposure limit is not emitted from the screen 120 as it is to the observer side.
Specifically, the following forms are adopted.

(A) Light Shielding on Screen FIG. 2 is a schematic diagram showing a cross-sectional structure of the screen 120.
As shown in FIG. 2A, the screen 120 includes a highly diffusive diffusion layer 121 in order to improve viewing angle characteristics and reduce speckles. In particular, in this embodiment, since the light source 101 is a laser light source with high straightness and coherence, strong diffusivity is required, and a light diffusion mechanism that uses a microlens array that is common in a rear projector is sufficient. Absent. Therefore, it includes a rather thick Mie scattering layer. Similar to a general rear projector, a Fresnel lens 122 may be prepared on the light source side of the screen 120 in order to eliminate the difference in viewing angle characteristics due to the difference in the location of the screen 120. In the case where the above-mentioned high diffusion layer 121 can make it close to complete diffusion, there is no need to use the Fresnel lens 122. In this embodiment, a resin layer (coloring layer) 123 that develops color by the heat of laser light is provided on the surface or inside of a member (a member including a high diffusion layer, a Fresnel lens, or the like) constituting the screen 120. When the work rate (W) per unit time reaches a predetermined threshold set based on AEL, that is, when the color forming layer 123 is excessively heated by the laser light L having energy exceeding AEL, It is adjusted to develop color. The principle of color development is the same as that of laser marking. That is, as shown in FIG. 2 (b), the material absorbs light energy according to the absorptivity of the laser beam, and the absorbed light energy is converted into thermal energy, and the temperature of the same part rises (rapidly). To do. Since the rate of this temperature rise is proportional to the magnitude of the energy of the given laser beam, the colored layer 123A at the same location melts and evaporates when the accumulated heat per unit time exceeds a set threshold value, and develops or changes color. . The position of the coloring layer 123 may be on the surface of a member constituting the screen 120 or inside (for example, below the AR coating layer). In the example of FIG. 2, the diffusion layer 121 is provided on the surface on the Fresnel lens 122 side. In the above example, a color-forming resin is used as the color-forming layer 123, but an inorganic color-forming material may be used. For example, silver ions used as a photographic photosensitizer can be used.

(B) Light Shielding with Reflection Mirror FIG. 3 is a schematic diagram showing a cross-sectional structure of the reflection mirror 109.
The reflection mirror 109 is a mirror for obtaining an optical path in the thin casing 110. As shown in FIG. 3 (a), a WAX layer 133, which is a solid layer, is placed on a black (absorbing) base material 131 made of carbon fiber FRP (CFRP) or the like, and AlNd (aluminum) is placed thereon. A light reflection film 132 having a high reflectance such as neodymium is formed. When the power per unit time reaches a predetermined threshold set based on AEL, that is, when heated excessively by laser light L having energy exceeding AEL, WAX layer 133 is melted by the heat. Has been adjusted. When the WAX layer 133 is melted, as shown in FIG. 3B, the light reflecting film 132 on the same layer is deformed or peeled off, and light is diffused in the former case, while light reflecting in the latter case. Absorption by the light-absorbing base material 131 (peeling portion P) exposed by peeling off the film 132 prevents dangerous laser light L from traveling toward the user side. The solid layer 133 is not limited to the WAX layer, and any material may be used as long as the material is adjusted to melt when heated excessively by the laser beam L having energy exceeding AEL. The base 131 is not limited to the above as long as it has a material having an absorption wavelength in the wavelength range of the laser beam.

(C) Light shielding by the projection lens When the swing angle by the scanner 106 is not sufficient, the projection lens 108 for enlarging the swing angle of the beam is necessary so that the laser beam can be distributed over the screen. A light shielding mechanism similar to that of the screen 120 can be applied to the projection lens 108. That is, by providing a coloring layer on the surface or inside of the projection lens 108, it is possible to absorb light having energy exceeding the AEL and prevent such high-intensity light from being emitted to the viewer side. Alternatively, as shown in FIG. 4, when the power per unit time of the projection lens 108 reaches a predetermined threshold set based on the AEL, that is, when the projection lens 108 is excessively heated by laser light having energy exceeding the AEL. It is made of a material that undergoes phase transition (melting, sublimation, etc.) due to the heat (for example, acrylic adjusted as such), and prevents the laser beam L from going straight due to deformation of the lens or generation of bubbles B in the lens, or diffusion. You may make it make it. The projection lens 108 is not necessary when a sufficient scan angle can be obtained on the scanner side.

(D) Light shielding by the scanner The scanner 106 scans the laser beams of R, G, and B in a two-dimensional direction and forms images by scanning the laser spots irradiated on the screen, respectively. Device. The horizontal scan and the vertical scan may be performed by one device (that is, a two-axis scan is performed by one scanner device), and the horizontal and vertical scans may be performed by separate devices. . In the present embodiment, a silicon MEMS scanner capable of two-axis scanning is used.

FIG. 5 is a schematic diagram illustrating an example of the scanner 106.
As shown in FIG. 5A, the scanner 106 is roughly configured by a frame body 141 provided in a substantially rectangular frame shape and a reflection mirror section 142 provided inside the frame body 141. A first rotation shaft 143 that is directed inward is provided at the center position of the pair of opposite sides of the frame body 141, and the second position that is directed outward is provided at the center position of the pair of sides orthogonal to the frame 141. A rotating shaft 144 is provided. The inner end portion of the first rotating shaft 143 is connected to the reflecting mirror portion 142 located inside the frame body 141, and the reflecting mirror portion 142 is connected to the first rotating shaft 143 and the second rotating shaft 143. The movable shaft 144 is configured to be rotatable in two axial directions.

  As shown in FIG. 5 (b), the operating reflection mirror 142 has a structure in which a WAX layer 106c, which is a solid layer, and a light reflection film 106b are sequentially stacked on the surface of a movable plate 106a made of silicon. Based on the same principle as in the case of the reflective mirror 109, when light having a predetermined work rate or higher is irradiated, that is, when the power per unit time reaches a predetermined threshold set based on the AEL, The laser beam L having a dangerous intensity due to deformation or peeling is prevented from moving toward the user side. Since the reflectance of visible light is low, when the mirror is peeled off and the underlying silicon layer is exposed, light can be sufficiently absorbed by the exposed portion. When horizontal scanning and vertical scanning are performed by separate devices, the light shielding function may be provided in either one or both.

  Note that the solid layer 106c is not limited to the WAX layer, and any material may be used as long as the material is adjusted so as to be melted by heat when heated excessively by laser light having energy exceeding AEL. Further, the movable plate 106a is not necessarily made of silicon as long as it has an absorption wavelength region in the wavelength region of laser light.

(E) Light shielding by lens optical system (collimating optical system, beam shaping optical system) The light shielding mechanism similar to that of the projection lens 108 can be applied to the lens optical system 103. That is, it is possible to adopt a configuration in which a color developing layer is provided on the surface or inside of the lens, or the lens is formed of a material that undergoes phase transition when heated to a certain temperature or higher.
The light shielding function may be provided in one of the collimating optical system 104 and the beam shaping optical system 105, or may be provided in both.

In addition, as a failure mode, (a) the operation of the scanner 106 is normal and the output intensity of the light source 101 is abnormal, and (b) the output intensity of the light source 101 is normal and the operation of the scanner 106 is abnormal. (When the scanner 106 has stopped due to a failure), different AELs are set for these (a) and (b). For example, assuming the display 30-inch 1080p, the laser power for (a) is allowed to 1.12mW / mm ^2, it is allowed to 8.35mW / mm ² for (b). Therefore, in the present embodiment, in order to satisfy both safety standards (a) and (b), the optical member arranged before the scanner in the optical path of the laser light is set to the first case set in the case of (a). AEL (first exposure release limit) is applied, and the second AEL (second exposure release limit) set in the case of (b) is applied to the optical member arranged after the scanner. is doing. That is, the lens optical system 103 and the scanner 106 are configured to be damaged or altered by the laser output exceeding the first AEL, and the projection lens 108, the reflection mirror 109, and the screen 120 are damaged by the laser output exceeding the second AEL. Or it is comprised so that it may change in quality.

As described above, according to the projector 100 of the present embodiment, the laser beam is shielded by directly damaging the optical member without complicated control as in the conventional case. Regardless, the safety of the display can be ensured.
Since the optical member having such a safety mechanism has a special structure for breaking or deteriorating, it requires more cost than a normal one. (D), (E) When the structure is applied to an optical member arranged before the magnifying optical system 108 as described above, the size of the optical member can be reduced by adjusting the magnifying factor, and thus the cost increases. Can be minimized.

[Second Embodiment]
FIG. 6 is a schematic diagram showing a configuration of a projector according to the second embodiment of the present invention.
As shown in FIG. 6A, a projector 200 according to this embodiment includes a light source 101 that emits laser light, a lens optical system 103 that includes a collimating optical system and a beam shaping optical system, and two-dimensionally incident laser light. A scanner 106 that scans in the direction, a condensing optical system 150 that collects the scanned light, a reflecting mirror 160 that reflects the collected light, and an enlarging optical system 108 that projects the reflected light toward the screen 120 in an enlarged manner Is schematically configured.

  In the projector 200, the laser light emitted from the light source 101 is shaped into substantially parallel light with high directivity by the lens optical system 103, and then scanned in a two-dimensional direction by the scanner 106. The light emitted from the scanner 106 is once condensed by the condensing lens 150 which is a condensing optical system, and enters the reflection mirror 160 as light having a small beam diameter. Then, the light is reflected toward the projection lens 108 which is a magnifying optical system. After being magnified here, the light is magnified and projected on the screen 120, and is transmitted through the screen 120 and visually recognized by an observer.

  In the projector 200, the configurations of the light source 101, the lens optical system 103, the scanner 106, the magnifying optical system 108, and the screen 120 are the same as those in the first embodiment. The only difference is that a condensing optical system 150 and a reflecting mirror 160 are installed between the magnifying optical system 108 and the scanner 106.

  The configuration of the reflection mirror 160 is the same as that of the first embodiment. That is, as shown in FIG. 6B, a WAX layer 163 that is a solid layer is provided on a light-absorbing substrate 161, and a light reflection film 162 having a high reflectance such as AlNd is formed thereon. ing. The WAX layer 163 is melted by the heat when the power per unit time reaches a predetermined threshold set based on the AEL, that is, when the WAX layer 163 is excessively heated by the laser beam having energy exceeding the AEL. It has been adjusted. When the WAX layer 163 is melted, the light reflecting film 162 on the same layer is deformed or peeled off. In the former case, light diffuses. In the latter case, the light reflecting film 162 peels off and is exposed. By being absorbed by the base material 161, dangerous intensity laser light is prevented from going to the user side. Note that the solid layer 163 is not limited to the WAX layer, and any material may be used as long as the material is adjusted to melt when heated excessively by laser light having energy exceeding AEL.

  In the projector 200 of the present embodiment, the laser beam is shielded by physically damaging the reflection mirror 160 or the like. For this reason, the safety can be ensured more reliably as compared with the conventional one in which malfunction is detected by a sensor or the like. The reflecting mirror 160 having such a safety mechanism has a special structure for breaking or deteriorating the structure, and thus requires more cost than a normal one. Since the size of the reflecting mirror 160 is reduced by condensing the light by the optical optical system 150 and then enlarging the light by the magnifying optical system 108, such an increase in cost can be minimized. .

[Third Embodiment]
FIG. 7 is a schematic diagram showing a configuration of a projector according to the third embodiment of the present invention.
As shown in FIG. 7, the projector 300 of this embodiment includes a light source 101 that emits laser light, a lens optical system 103 that includes a collimating optical system and a beam shaping optical system, and scanning the incident laser light in a two-dimensional direction. The scanner 106, the reflecting mirror 160 that reflects the scanned light, and the magnifying optical system 170 that magnifies and reflects the reflected light toward the screen 120 are roughly configured.

  In the projector 300, the laser light emitted from the light source 101 is shaped into substantially parallel light with high directivity by the lens optical system 103, and then scanned in a two-dimensional direction by the scanner 106. The light emitted from the scanner 106 is reflected by the reflecting mirror 160 toward the curved reflecting mirror 170 which is an enlarging optical system. After being enlarged here, the light is enlarged and projected onto the screen 120 and transmitted through the screen 120. Visible to an observer.

  In the projector 300, the configurations of the light source 101, the lens optical system 103, the scanner 106, and the screen 120 are the same as those in the first embodiment. The only difference is that the magnifying optical system 170 is a curved reflecting mirror and that the reflecting mirror 180 is installed between the magnifying optical system 170 and the scanner 106.

FIG. 8 is a schematic diagram showing a cross-sectional structure of the reflection mirror 180.
As shown in FIG. 8A, the reflecting mirror 180 has a configuration in which a light reflecting film 182 made of a low melting point material such as Au, Ag, Al or the like is provided on a light-absorbing substrate 181. The light reflecting film 182 is melted by the heat when the power per unit time reaches a predetermined threshold set based on the AEL, that is, when the light reflecting film 182 is excessively heated by the laser light L having energy exceeding the AEL. Have been adjusted so that. As shown in FIG. 8B, when the light reflecting film 182 is deformed or peeled off by melting, the light is diffused in the former case, and the light reflecting film 182 is peeled off and exposed in the latter case. Absorption by the light-absorbing substrate 181 prevents the laser beam L having a dangerous intensity from moving toward the user.

FIG. 9 is a schematic diagram showing another form of the reflection mirror 180.
As shown in FIG. 9A, the reflecting mirror 180 includes a light reflecting film 182 made of a low-melting-point material such as Au, Ag, Al on the light incident side of a translucent substrate 183 so that light is incident. The light absorption layer 184 is provided on the side opposite to the side. The configuration of the light reflecting film 182 is the same as that of FIG. As shown in FIG. 9B, when the light reflecting film 182 is deformed or peeled off by melting, the light is diffused in the former case, and the light reflecting film 182 is peeled off and exposed in the latter case. By passing through the translucent base material 183 and being absorbed by the light absorption layer 184 disposed on the back surface side, the laser beam L having dangerous intensity is prevented from traveling toward the user side.

  In the projector 300 of the present embodiment, the laser beam is shielded by physically damaging the reflection mirror 180 or the like. For this reason, the safety can be ensured more reliably as compared with the conventional one in which malfunction is detected by a sensor or the like. The reflection mirror 180 provided with such a safety mechanism has a special structure for breaking or deteriorating the structure, and thus requires more cost than a normal one. Since the size of the reflection mirror 180 is reduced by adjusting the enlargement ratio using the optical system 170, such an increase in cost can be minimized.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 100,200,300 ... Projector, 101 ... Light source, 103 ... Lens optical system, 104 ... Collimating optical system, 105 ... Beam shaping optical system, 106 ... Scanner, 106a ... Movable plate, 106b ... Light reflection film, 106c ... Solid layer , 108 ... Projection lens (enlarged optical system) 109 ... Reflection mirror, 120 ... Screen, 123 ... Color development layer, 131 ... Absorbing substrate, 132 ... Light reflection film, 133 ... Solid layer, 143, 144 ... Rotation Axis, 160 ... reflecting mirror, 161 ... absorbing substrate, 162 ... light reflecting film, 163 ... solid layer, 170 ... curved reflecting mirror (magnifying optical system), 180 ... reflecting mirror, 181 ... absorbing substrate, 182: Light reflecting film, L, L0: Laser light

Claims (6)

A light source that emits laser light; and a scanner that scans the laser light on a screen, and when laser light having an energy exceeding the exposure limit is output due to failure of the light source or the scanner, A rear projection type projector configured such that at least one optical member disposed on an optical path is damaged or altered, and light having an energy exceeding the exposure limit is not emitted from the screen,
One of the optical members is a collimating or beam shaping lens arranged on the optical path of the laser light between the scanner and the light source, and the operation of the scanner is normal and the output of the light source When the maximum exposure level allowed when the intensity is abnormal is the first exposure limit, the collimating or beam shaping lens is phased by the heat of the laser light exceeding the first exposure limit. A projector comprising a material that causes a transition.   The scanner includes a movable plate that is rotatable about a predetermined rotation axis, a solid layer that is melted by the heat of the laser light that exceeds the first emission limit, and the movable plate that is disposed through the solid layer. The projector according to claim 1, further comprising a light reflecting film formed on the surface.   The projector according to claim 2, wherein the movable plate is made of a material having an absorption wavelength region in a wavelength region of the laser light. A light source that emits laser light; and a scanner that scans the laser light on a screen, and when laser light having an energy exceeding the exposure limit is output due to failure of the light source or the scanner, A rear projection type projector configured such that at least one optical member disposed on an optical path is damaged or altered, and light having an energy exceeding the exposure limit is not emitted from the screen,
One of the optical members is a projection lens disposed on the optical path of the laser beam between the scanner and the screen, and the output intensity of the light source is normal and the scanner is stopped due to a failure. The projection lens is made of a material that causes a phase transition by the heat of laser light exceeding the second exposure release limit when the maximum exposure level allowed in the case of the failure is the second exposure release limit. A projector characterized by that.   A reflecting mirror is provided on the optical path of the laser light between the scanner and the screen, and the reflecting mirror is melted by the heat of the laser light that exceeds the substrate and the second exposure limit. The projector according to claim 4, further comprising: a layer; and a light reflecting film formed on the surface of the base material via the solid layer.   The projector according to claim 5, wherein the base material is made of a material having an absorption wavelength region in a wavelength region of the laser light.

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