JP2011137878A - Projection type video display and intrusion detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video of high luminance to secure safety of an observer in a projection type video display using a laser beam source. <P>SOLUTION: A projection type video display projects images on a projection face by using a laser beam. An information input part 102 receives characteristic information which is information for determining intensity of the laser beam incident on a pupil of the observer from the projection face as input. A distance calculation part 104 calculates a safe distance by which the observer should be separated from the projection face on the basis of the characteristic information. A space setting part 106 sets a space including a distance up to the safe distance from the projection face as an intrusion ban space to keep away the observer. A detection part 108 detects intrusion of the observer to the intrusion ban space. A permission part 112 determines whether the laser beam emits on the basis of result of intrusion detection with the detection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projection display apparatus that projects an image on a projection surface and a startup method thereof.

  In recent years, short-focus projectors that can extremely shorten the installation distance to a projection surface such as a screen have appeared. For example, a type capable of projecting a large-screen image even if it is installed at a position almost in contact with a wall to be a projection surface has been put into practical use. Such a short focus projector can reduce the projection distance, and thus can effectively use the space.

  In addition, projectors that use lasers with high radiation energy as light sources have also appeared. Conventionally, many laser light source projectors are of the rear projection type, but recently there are projectors that project images from the front side. In such a projector, an image using laser light as a light source is projected from the viewer's side, so it is necessary to take some means for protecting the viewer.

  For example, in Patent Document 1, in a projection display device that displays an image using laser light, the brightness on the screen is within a range in which the optical power per unit area of the laser light conforms to a predetermined safety standard. It is disclosed that the amount of laser light is controlled so that the maximum value can be secured.

JP 2009-210619A

  However, when the light amount of the laser light is set based on the brightness on the screen as in Patent Document 1, the setting is too safe, and the observer can observe the image with a brightness much lower than the allowable value. There is sex.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide an intrusion of an observer from the viewpoint of laser light intensity based on various kinds of information in a projection display apparatus, particularly a short focus projection display apparatus. It is to provide a technique for setting an area to be prohibited.

  In order to solve the above-described problems, a projection display apparatus according to an aspect of the present invention is a projection display apparatus that projects an image on a projection plane using laser light, and is projected from the projection plane to an observer's pupil. An input unit that receives, as an input, characteristic information that is information for determining the intensity of incident laser light, a distance calculation unit that calculates a safe distance that is the distance that the observer should be away from the projection surface, based on the characteristic information, and a projection A space setting unit that sets a space including a safe distance from the surface as an invasion-prohibited space that should keep the observer away

  Another aspect of the present invention is an intrusion detection method in a projection display apparatus that projects an image on a projection surface using a laser light source. This method receives, as input, characteristic information that is information for determining the intensity of laser light incident on the observer's pupil from the projection plane, and based on the characteristic information, a safe distance that is the distance that the observer should be away from the projection plane And the space including the safe distance from the projection plane is set as an invasion-prohibited space that should keep the observer away, and the intrusion of the observer into the invasion-prohibited space is detected. Including determining whether or not emission is possible.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between a method, an apparatus, a system, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to further improve the safety of an observer, particularly in a projection display apparatus using a laser light source.

It is a figure which shows the example of installation of a short focus projection type video display apparatus. FIG. 1A is a view of the projection surface and the projection display apparatus from the front, and FIG. 1B is a view of the projection plane and the projection display apparatus from above. It is a figure which shows schematically the side surface cross section of the projection type video display apparatus shown in FIG. It is a figure which shows the structural example of the optical system of the projection type video display apparatus shown in FIG. It is a functional block diagram of a control unit provided in the projection display apparatus. 4 is a flowchart of a process for calculating a safe distance, which is mainly executed by a distance calculation unit 104. It is a figure explaining the light energy which injects into an observer's pupil from the micro area on a screen. 6 is a table defining the maximum exposure tolerance in the cornea for direct eye exposure of laser radiation. It is a table | surface which shows an example of characteristic information. It is a figure which shows the intrusion prohibition area | region set around the screen. It is a figure which shows an example of the installation position of a camera, and an imaging | photography range. It is a figure which shows the example which changes the view angle or imaging | photography direction of a camera. It is a flowchart of the intrusion detection process by a projection type video display apparatus.

  FIG. 1 is a diagram illustrating an installation example of a short-focus projection display apparatus 100. FIG. 1A is a view of the projection plane 200 and the projection display apparatus 100 as viewed from the front, and FIG. 1B is a view of the projection plane 200 and the projection display apparatus 100 as viewed from above.

  The housing of the projection display apparatus 100 shown in FIG. 1 has a rectangular parallelepiped shape that is longer than the height and depth. FIG. 1 shows an example in which a projection surface 200 such as a screen or a wall is in contact with the floor surface. The projection display apparatus 100 is installed on the floor surface, and the front surface of the housing is connected to the projection surface 200. It is installed at a position where it substantially touches. In the projection surface 200, a projection area 250 in which a projection image projected from the projection display apparatus 100 is to be projected is provided. A projection port 130 is provided on the upper surface of the casing of the projection display apparatus 100, and light emitted from the projection port 130 is guided to the projection region 250.

  FIG. 2 is a diagram schematically showing a side cross-section of the projection display apparatus 100 shown in FIG. The optical system 90 provided in the projection display apparatus 100 includes a reflection mirror 80, and light emitted from a projection lens, which will be described later, is reflected by the reflection mirror 80, passes through the projection port 130, and is projected onto the projection surface 200. And is diffused or condensed by the projection surface to reach the observer's pupil.

  FIG. 3 is a diagram showing a configuration example of the optical system 90 of the projection display apparatus 100 shown in FIG. In this configuration example, three primary color laser light sources (red light source 10R, green light source 10G, and blue light source 10B) are provided. A plurality of red light sources 10R, green light sources 10G, and blue light sources 10B may be provided. Each light source is connected to an optical fiber. The optical fibers connected to each light source are bundled by the fiber bundle 20, and the light emitted from the end of each optical fiber is the rod integrator 30, the first relay lens 41, the first mirror 42, the second relay lens 43, The light enters the color separation / combination prism 50 via the second mirror 44 and the third relay lens 45. The three laser light sources may be configured to be replaceable as the laser light source unit 72.

  The light incident on the color separation / combination prism 50 is separated into red light, green light, and blue light by the red prism 50R, the green prism 50G, and the blue prism 50B that constitute the light. The separated red light, green light, and blue light are respectively incident on the reflective red light modulation element 60R, green light modulation element 60G, and blue light modulation element 60B. For example, DMD (Digital Micro-mirror Device) can be adopted for the red light modulation element 60R, the green light modulation element 60G, and the blue light modulation element 60B. The red light modulation element 60R, the green light modulation element 60G, and the blue light modulation element 60B modulate the incident red light, green light, and blue light, respectively, according to the set image signals of the respective colors.

  The light paths of the red light, the green light, and the blue light modulated by the red light modulation element 60R, the green light modulation element 60G, and the blue light modulation element 60B are integrated by the red prism 50R, the green prism 50G, and the blue prism 50B. Is incident on the projection lens 70 from the color separation / combination prism 50.

  The projection lens 70 widens the light incident from the color separation / synthesis prism 50 and outputs the light to the reflection mirror 80. The reflection mirror 80 further widens the light incident from the projection lens 70 and guides the light from the projection port 130 to the projection surface 200 (see FIG. 2). The reflection mirror 80 may be an aspherical mirror. The projection lens 70 and the reflection mirror 80 may be configured to be replaceable as an integrated projection optical system unit 74.

  By the way, in the projection type image display apparatus using the conventional laser light source, the projection surface is used in view of the maximum permissible exposure amount in the cornea for direct eye exposure (MPE: Maximum Permissible Exposure, see laser product safety standards (JIS C 6802)). Many of them control the laser light intensity. This is based on the idea that if the safety is ensured on the projection surface, the laser light after receiving the effect of the projection surface is also safe.

  However, when a transmissive Fresnel lens screen is used instead of a normal screen with high diffusivity as the projection surface, the laser light intensity per unit area is more on the viewer side than on the screen if there is an extreme light condensing function. It can happen that becomes larger. In addition, if the laser light intensity on the screen is controlled to MPE below, it may happen that the observer is observing an image with lower brightness than necessary. That is, MPE is a standard of light intensity in the cornea of an observer and should not be evaluated on the projection plane.

  On the other hand, the inventors of the present application, even if the intensity of the laser beam exceeds the MPE on the projection surface, if the observer observes a certain distance away from the screen, the screen's diffusing action causes the observer's cornea. We focused on the fact that the light intensity at is lower than MPE. At this time, as long as safety measures are taken so as not to get too close to the projection surface, the observer can observe an image with higher brightness than before.

  Therefore, in the present embodiment, the range where the MPE in the observer's cornea becomes the upper limit is set as the intrusion prohibited area, and the observer's intrusion into the prohibited area is monitored.

  FIG. 4 is a functional block diagram of the control unit 88 provided in the projection display apparatus 100. These configurations can be realized by an arbitrary processor, memory, or other LSI in terms of hardware, and can be realized by a program loaded in the memory in terms of software, but here by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  The information input unit 102 receives, as an input, characteristic information that is information for determining the intensity of laser light incident on the observer's pupil from the projection plane 200.

  The characteristic information can be classified according to various criteria. For example, the characteristic information can be classified into a characteristic relating to the light flux from the screen (referred to as “projected light flux characteristic”) and a characteristic relating to the screen itself (referred to as “screen characteristic”). Furthermore, the projected light beam characteristics can be classified into the characteristics of the light source unit constituting the projection display apparatus 100 and the characteristics of the projection optical system. The light source unit characteristics include characteristics such as luminous flux, uniformity, laser wavelength, white balance, and the like that may change when the light source unit is replaced. Further, the projection optical system characteristics include characteristics that may be changed by replacing the projection optical system, such as light flux, peripheral light amount ratio, spread angle, F value, uniformity, magnification, and white balance. Screen characteristics include screen size, gain, viewing angle characteristics, screen color, and the like.

As another classification of the characteristic information, physical characteristics relating to the projection display apparatus 100 and the projection plane 200 and user characteristics that can be set by an observer may be used. In this case, physical characteristics include light flux, uniformity, laser wavelength, peripheral light amount ratio, spread angle, F value, magnification, and the like, and user characteristics include screen size, gain, white balance, and the like.
Note that the above characteristic information is an example, and the information input unit 102 can receive any information that affects the intensity of the laser light as the characteristic information.

The information input unit 102 receives characteristic information input from the user using various buttons and screens provided in the operation instruction unit 86. The information input unit 102 may be connected to a terminal such as a personal computer and receive characteristic information input therefrom. When the light source unit or the projection optical system unit includes the light source unit recording unit 82 or the projection optical system unit recording unit 84 in which the physical characteristics of each unit are recorded, the information input unit 102 is connected to each recording unit. The characteristic information may be acquired automatically.
Since the screen is not connected to the projection display apparatus, the user inputs the screen characteristics using the operation instruction unit 86. Alternatively, the information input unit 102 may automatically acquire the screen size by photographing the screen with a camera described later.

  The distance calculation unit 104 calculates a safe distance D, which is the distance that the observer should be away from the projection plane 200, based on the characteristic information obtained by the information input unit 102. The safety distance corresponds to NOHD (nominal eye damage distance) defined by the safety standard of laser products (JIS C 6802), and is set in order to protect the observer from damage caused by laser light.

  The space setting unit 106 sets a space including a safe distance from the projection plane 200 as an intrusion prohibited space in which the observer should be kept away. Since the safe distance is calculated assuming laser light diffused by the screen, it is necessary to leave the safe distance from every point on the screen. Therefore, the intrusion prohibited space is a three-dimensional space that covers the entire screen, as will be described later.

  The detection unit 108 images an intrusion prohibited space using an imaging unit such as a CCD camera, and detects an observer's entry into the intrusion prohibited space. The camera may be installed in the casing of the projection display apparatus or may be installed separately from the projection display apparatus. The camera and the control unit of the display device are connected by wire or wireless so that data can be exchanged with the control unit. As will be described later, the camera is preferably configured such that the installation position, installation angle, angle of view, shooting direction, and the like can be changed within a certain range.

  The imaging range instruction unit 110 controls the camera so that the entire intrusion prohibited space is included in the imaging range according to the value of the safety distance calculated by the distance calculation unit 104. This is because if the safe distance value changes, the range of the invasion-prohibited space also changes, and therefore, the entire range of the invasion-prohibited space may not be covered by the initial shooting range of the camera.

  The permission unit 112 determines whether or not laser light can be emitted based on the result of intrusion detection by the detection unit 108. Then, the light source unit is instructed not to emit laser light.

  Hereinafter, the safety distance calculation process mainly executed by the distance calculation unit 104 will be described with reference to the flowchart of FIG. 5 as appropriate.

  First, the distance calculation unit 104 obtains the illuminance E = Φ / A on the screen using the luminous flux Φ, the peripheral light amount ratio, and the screen area A, and then uses the screen gain (the reflection characteristic inherent to the screen fabric). The brightness B on the screen is obtained (S10).

Then, the distance calculation unit 104, emitted from a minute area S _n on the screen, calculates the light flux [Phi _n to enter the observer's pupil (S12).

FIG. 6 is a diagram for explaining a light beam incident on an observer's pupil from a small area on the screen. In the figure, the minute region S _n located in the center of the projection area 250 represents a light beam incident on the pupil P of the observer positioned away from the center of the screen to the surface normal direction by a distance D. The diameter of the pupil P is set to 7 mm. If the micro area is 10 mm × 10 mm, the light flux Φ _n incident on the pupil from this area is
Φ _n (lm) = B (cd / m ² ) · A (m ² ) · Ω (str)
Where Ω is the solid angle of the pupil.

Subsequently, the distance calculation unit 104 calculates the light flux Φ _all incident on the region P corresponding to the pupil from the entire screen (S14). This can be determined by dividing the entire screen example of 10 mm × 10 mm a minute area S _n, summing the light beams incident on the pupil P of φ7mm from each micro area. For example, when the angle between the normal line and the straight line connecting the minute area and the pupil P is θ, the light flux from each minute area is obtained by Φ _n · cos θ.

Next, the distance calculation unit 104 calculates the light energy of each color of the laser (S16). First, the brightness ratio of the laser light for achieving the set white balance is calculated using the laser wavelengths used for the R light, the G light, and the B light and the visibility data obtained from the laser wavelengths. Subsequently, the light energy of each color of the laser light and the combined energy thereof are calculated from the luminance ratio and the light flux Φ _all calculated in S14.

The distance calculation unit 104 calculates the MPE for each color as a safety index based on the wavelength of the laser light source (S18). For MPE in the cornea, the exposure time is set to a sufficient value for safety. Here, it is assumed that it is safe at the time of continuous viewing for 8 hours and 20 minutes in accordance with the longest condition value 3 × 10 ⁴ (seconds) of the exposure time.
The MPE for each color alone is determined as follows based on the MPE in the cornea for direct eye exposure of laser radiation as shown in FIG.
・ R light (641nm)
From α> 100 mrad M _R = 18C ₆ T ₂ ^−0.25 = 18 × 66.7 × 100 ^−0.25 = 3.80 × 10 ² (W / m ² )
Here, α is a viewing angle when the pupil sees the entire screen, and here, the calculation is made for a case where α> 100, which is more severe.
・ G light (532nm)
M _G = 1C ₃ = 1 × 10 ^{(0.02 × (533-450))} = 4.57 × 10 (W / m ² )
・ B light (465nm)
M _B = 1C ₃ = 1 × 10 ^{(0.02 × (465-450))} = 2.00 (W / m ² )

The distance calculation unit 104 calculates MPE as combined light having a plurality of wavelengths (S20). In order to obtain the MPE of the combined light, it is necessary to derive the exposure amount allowed for each wavelength. The MPE of each RGB wavelength when using a single wavelength _{M R, M G, M B} (W / m 2), the exposure amount of each RGB wavelength when reaching the observer's pupil as combined light _{E R} , E _G , E _B (W / m ² ), a combination of E _R , E _G , and E _B that satisfies the condition of the following expression 1 is an exposure amount allowed at each wavelength.

Here, in the projection display apparatus, white chromaticity coordinates (white balance), which is the highest luminance, are determined, and the ratio of each luminance of RGB is determined by the white balance and the wavelength of each laser beam. Note that the luminance ratio and the exposure amount ratio need to be converted between the light measurement system and the radiation system.
From the above, the screen luminance ratio of each color _{L R: L G: L B} (L R + L G + L B = 1), the visibility _{V (λ R), V (} λ G), V (λ B) Then, the respective exposure amount ratios are L _R / V (λ _R ): L _G / V (λ _G ): L _B / V (λ _B ).
Assuming that the exposure amount of the RGB combined light in the trend of the observer is EW (W / m ² ), the exposure amounts E _R , E _G , and E _B of each wavelength are expressed as follows.
From Equation 1 and Equation 2, MPE: MW (W / m ² ) of the synthesized light is derived as follows.

  Finally, D satisfying Equation 1 is obtained using the distance D as a variable (S22). This D is a safe distance.

(Example)
In the projection display apparatus configured as described above, an example of calculating the prohibited area using actual numerical values will be described below.

  FIG. 8 shows an example of characteristic information. Here, light flux, peripheral light quantity ratio, used laser wavelength and white balance are defined as projected light flux characteristics, and size and gain are defined as screen characteristics.

In the actual calculation, the above calculation is executed with the safety distance D as a variable. Here, for the sake of simplicity of explanation, the calculation is shown assuming that the distance D = 6 m.
First, the luminance E on the screen is E = 3628 (lx) using Φ = 10000 (lm) and A = 2.214 × 1.245 (m ² ) under the condition of the peripheral light quantity ratio of 100%. Since the screen gain is 1, luminance B = 3628 × 1 / π = 1155 (cd / m ² ).
Next, the light flux Φ _n emitted from the minute region Sn on the screen and incident on the pupil is B = 1155, S _n = (10 × 10 ⁻³ ) ² , Ω = 2π × (1-cos (atan (3. 5/6000))), Φ _n = 1.23 × 10 ⁻⁷ (lm).
When the light flux Φ _all incident on the pupil from the entire screen is added for all Φ _n , Φ _all = 3.07 × 10 ⁻³ (lm).

Next, in order to set the white balance to D65, the luminance ratio is as follows.
Using this, the output energy of each color of RGB is obtained by Φ _all × j / 683 / k, R: 1.71 × 10 ⁻¹ (W / m ² ), G: 3.93 × 10 ^{−1, respectively.} (W / m ² ), B: 3.34 × 10 ⁻¹ (W / m ² ).

Next, the MPE when the white balance is set to D65 (chromaticity coordinates x = 0.3128, y = 0.3292, color temperature 6500K) is calculated using the laser light sources for the respective colors RGB. Since the chromaticity coordinates of each color light source of the laser are determined, the allowable exposure amount ratio using each formula is calculated as the following formula.
The MPE as the multi-wavelength synthesized light is M _w = 7.79 (W / m ² ) from Equation 3. When D is obtained from Equation 1 using D as a variable, D = 1.2 is obtained.

  Next, a method for monitoring the observer's entry by setting the entry prohibition area after calculating the safe distance D will be described in detail.

  FIG. 9 is a diagram showing an intrusion prohibition area set around the screen. When the screen gain is 1, since intrusion detection must be executed for an observer who enters within a safe distance D from any point on the screen, the intrusion prohibited area is a screen as indicated by a dotted line in the figure. It becomes a three-dimensional space that covers the whole.

FIG. 10 is a diagram illustrating an example of installation positions of the cameras 150L and 150R connected to the detection unit 108. FIG. 10 is a view of the projection display apparatus 100 and the projection surface 200 as viewed from above. The outer edge of the intrusion prohibited area is indicated by a dotted line. In this example, one camera is installed on each of the left and right corners of the casing of the projection display apparatus 100. First camera 150L is installed in the left front of the housing, including a right half of the forbidden entry area as the imaging range M _L. Second camera 150R is installed on the right front side of the housing, including the left half of the old and new forbidden area as an imaging range M _R. As described above, by installing the two cameras in the projection display apparatus 100, the entire intrusion prohibited area can be included in the imaging range.

  Images taken by the first camera 150L and the second camera 150R are acquired by the detection unit 108, and image analysis is performed by a known method. For example, an intruding object can be detected by applying a background subtraction method or interframe difference to a photographed image.

  It is desirable that the detection unit 108 not only detect the intruding object but also determine the distance to the intruding object. Since the shooting range of the camera includes parts other than the intrusion prohibited area, if it is determined that the camera is intruding simply because it is captured by the camera, it is determined that an observer who is more than the safe distance D from the screen has also entered. Because it will end up. As a method for determining the distance, there are a method of estimating the distance by image analysis, a method of using a measurement refusal means such as an infrared sensor, and the like. Alternatively, after the safety distance D has been calculated, the place where the user moves through the outer edge of the intrusion prohibited area is photographed with two cameras, and the image at this time is used as a reference for intrusion detection. Good.

  As described above, the value of the safety distance D is increased or decreased by changing the light source unit or the projection optical system unit, changing the screen, changing the user setting, or the like. Therefore, it is preferable that the camera is configured to fit the entire area within the photographing range even when the safety distance D increases and the intrusion prohibited area expands. For example, in FIG. 10, if the shooting ranges of the two cameras 150L and 150R cannot be changed, the point A is included in the shooting range when the safety distance D = 1.2 m, but the point B is set when D = 1.5 m. It will be out of the shooting range.

FIG. 11 shows an example of a camera that can change the shooting range. In FIG. 11A, the cameras 150L and 150R are configured so that the angle of view can be changed by adjusting the lens, respectively. When it is determined that the safety distance D increases from the beginning, for example, the point B is out of the shooting range, the shooting range instruction unit 110 enlarges the angle of view with respect to the second camera 150R (or the first camera 150L). To instruct. As a result, it is possible to capturing range M _R of the second camera 150R is expanded as shown by the solid line from the dotted line in the figure, it fits the point B to the shooting range.
In FIG. 11B, the cameras 150L and 150R are installed together with a rotation driving mechanism for rotating the imaging direction. When it is determined that the safety distance D has increased from the beginning, for example, the point B is out of the shooting range, the shooting range instruction unit 110 detects the rotation drive mechanism of the second camera 150R (or the first camera 150L). Instructs to change the shooting direction. As a result, it is possible to capturing range M _R of the second camera 150R is expanded as shown by the solid line from the dotted line in the figure, it fits the point B to the shooting range.

  Therefore, it is desirable to install the camera so that the angle of view can be changed. The angle of view of the camera is configured so that it can be moved manually, or is installed together with a rotation mechanism for rotating the imaging direction. In the former case, guidance information for adjusting the angle of the camera so that the prohibited area is included in the photographing range of the camera may be provided to the user from the projection display apparatus. In the latter case, the monitoring unit may adjust the shooting direction and rotation angle of the camera by calculation based on the safety distance D.

  In addition to the above, one or both of the first camera 150L and the second camera 150R are installed together with a horizontal / vertical moving mechanism, or are installed together with a tilt mechanism that moves the optical axis of the camera up and down. These mechanisms may be driven in accordance with an instruction from the range instruction unit 110. These mechanisms may be manual. In this case, when the shooting range instruction unit 110 determines that a part of the intrusion prohibited area is outside the shooting range of the camera, the shooting range instruction unit 110 instructs the user to change the position, angle, tilt, and the like of the camera. It may be configured.

FIG. 12 is a flowchart of intrusion detection processing by the projection display apparatus according to this embodiment.
When the power of the projection display apparatus 100 is turned on (S30), the information input unit 102 reads characteristic information such as the projected light beam characteristic from the storage unit of each unit (S32). Display, voice guidance, or the like that prompts the user to selectively input characteristics of a device that is not connected to the projection display apparatus, such as screen characteristics, or characteristics set by the user, to the apparatus may be selectively output. (S34).

  The distance calculation unit 104 calculates the safe distance D between the screen and the observer according to the above-described procedure using the input characteristic information (S36). The space setting unit 106 sets a three-dimensional space that becomes an intrusion prohibited area from the safety distance D around the screen (S38). The shooting range instruction unit 110 sets the orientations and angles of view of the cameras 150L and 150R so that all of the intrusion prohibited areas are included in the shooting range of the camera (S40).

  The detection unit 108 monitors the image taken by the camera, and when the intrusion of the observer into the intrusion prohibited area is detected (Y in S42), the operation of the laser light source unit is prohibited (S44). At this time, a display or a sound for warning or recommending evacuation may be emitted to the observer. When the observer does not enter the intrusion prohibited area (N in S42), the operation of the laser light source unit is permitted (S46), and an image can be projected on the screen. Thereafter, the intrusion monitoring by the detection unit 108 is continued during the display of the video.

  As described above, according to the present embodiment, the intensity of the laser beam is not controlled by the MPE on the screen, but enters every time the projection display apparatus is started based on various characteristic information. The prohibited area was set. Therefore, even when the safety distance D is increased due to a change in the specification of the functional unit of the projection display apparatus or a change in setting by the user, the intrusion prohibited area is enlarged and reset. Therefore, the observer can observe the video with higher brightness than the conventional method, and at the same time, the safety of the observer can be ensured. Further, if the screen characteristics are input as the characteristic information, the intrusion prohibited area can be set regardless of whether the screen is a condensing type or a diffusing type.

  The present invention has been described based on some embodiments. It is understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. By the way.

  In the above-described embodiment, the camera is used to detect the intrusion of the observer into the intrusion prohibited space. However, an infrared sensor may be used instead of or in addition to the camera. For example, the infrared sensors are attached to the four corners of the casing of the projection display apparatus 100 and are arranged toward the outer intrusion prohibited area. Infrared return light is detected and the distance to the object is measured. If the measured distance is equal to or less than the safety distance D, it is determined that there is an intrusion. Alternatively, an infrared camera may be used instead of a normal camera.

  DESCRIPTION OF SYMBOLS 70 Projection lens, 80 Reflecting mirror, 82 Light source unit recording part, 84 Projection optical system unit recording part, 86 Operation instruction part, 88 Control unit, 90 Optical system, 100 Projection type image display apparatus, 102 Information input part, 104 Distance calculation Unit, 106 space setting unit, 108 detection unit, 110 photographing range instruction unit, 112 permission unit, 150 camera, 150L first camera, 150R second camera, 200 projection plane, 250 projection area.

Claims (7)

A projection display apparatus that projects an image on a projection surface using laser light,
An input unit that receives, as an input, characteristic information that is information for determining the intensity of laser light incident on the observer's pupil from the projection plane;
Based on the characteristic information, a distance calculation unit that calculates a safety distance that is a distance from which the observer should move away from the projection plane;
A space setting unit that sets a space including the safe distance from the projection plane as an invasion-prohibited space to keep the observer away;
A projection-type image display device comprising: A detection unit for detecting an intrusion of an observer into the intrusion prohibited space;
Based on the result of intrusion detection by the detection unit, a permission unit that determines whether laser light can be emitted,
The projection display apparatus according to claim 1, further comprising: It further comprises a photographing means installed so as to photograph the intrusion prohibited space,
The imaging unit according to claim 2, wherein the detection unit further includes an imaging range instruction unit that controls the imaging unit so that the entire intrusion prohibited space is included in the imaging range according to the value of the safety distance. The projection-type image display device described.   4. The projection display apparatus according to claim 1, wherein the characteristic information includes a characteristic of a projected light beam from the projection plane and a characteristic of the projection plane itself.   The projection image display apparatus according to claim 4, wherein the projected light beam characteristics include characteristics of a light source unit and a projection optical system constituting the projection image display apparatus.   4. The projection type according to claim 1, wherein the characteristic information includes physical characteristics relating to the projection display apparatus and the projection plane, and user characteristics that can be set by an observer. Video display device. In a projection display apparatus that projects an image on a projection surface using a laser light source,
Receiving as input characteristic information that is information that determines the intensity of the laser light incident on the observer's pupil from the projection plane;
Based on the characteristic information, calculate a safe distance that is a distance that the observer should leave from the projection plane,
A space including the safe distance from the projection plane is set as an invasion-prohibited space to keep the observer away,
Detecting an observer's entry into the invasion prohibited space,
An intrusion detection method in a projection display apparatus, comprising determining whether laser light can be emitted based on an intrusion detection result.