JP2023037420A - Projection display device and work device - Google Patents

Abstract

To provide a projection display device that can vividly illuminate a relatively wide region of an illumination target surface, and a work device with the projection display device.SOLUTION: A projection display device 10 includes: a laser light source 20; a diffraction optical element 30 for diffracting light emitted from the laser light source 20; and a first optical system 40 located on the optical path of light diffracted by the diffraction optical element 30. The first optical system 40 includes a first lens group 41 having a positive power, for receiving light diffracted by the diffraction optical element 30 and a second lens group 42 having a negative power, for receiving light emitted from the first lens group 41. The first optical system 40 has an angular magnification that is larger than 1.SELECTED DRAWING: Figure 3

Description

The present invention relates to a projection display device and a working device provided with the projection display device.

For example, working devices as disclosed in Patent Document 1 and Patent Document 2 are used in various fields. A work device performs some work while being moved in whole or in part. Examples of working devices include working machines such as an automatic carrier that transports articles by towing a trolley, and a hydraulic excavator.

These days, there is a demand for labor saving and automation in the use of working devices. For this reason, it is desired to mount a display device on the work device for calling attention to the surroundings of the work device. The display device informs the surroundings of the approach of the working device and the movable area while the working device is working.

JP-A-5-98674 JP 2015-081017 A

As such a display device, a projection type display device has been studied that displays by irradiating light onto a road surface or a floor surface on which a working device is arranged. When a projection type display device is used to provide a display that indicates the approach of the work device and the movable area, the projection type display device mounted on the work device is the road surface or floor surface on which the work device is arranged (thus, the projection type display device It is necessary to clearly illuminate a relatively wide area of the surface to be illuminated (at a relatively short distance from the light source).

An object of the embodiments of the present disclosure is to provide a projection-type display device and a working device with a projection-type display device that can clearly illuminate a relatively wide area of an illuminated surface.

A projection display device according to an embodiment of the present disclosure includes:
a laser light source;
a diffractive optical element that diffracts light emitted from the laser light source;
a first optical system provided on the optical path of the light diffracted by the diffractive optical element;
with
The first optical system is
a first lens group having a positive power into which the light diffracted by the diffractive optical element is incident;
a second lens group having negative power into which the light emitted from the first lens group is incident;
including
The angular magnification of the first optical system is greater than one.

In the projection display device according to one embodiment of the present disclosure, the diffraction angle of the light in the diffraction optical element may be 0±15° or less.

In the projection display device according to one embodiment of the present disclosure, the first optical system may form an imaging optical system.

In the projection display device according to one embodiment of the present disclosure, the first lens group and the second lens group are arranged such that the optical axes of the first lens group and the second lens group are aligned on the same straight line. And, the rear focal point of the first lens group may be aligned with the front focal point of the second lens group.

The projection display device according to an embodiment of the present disclosure further includes a scanning device that scans the diffraction optical element with the light from the laser light source by changing the traveling direction of the light emitted from the laser light source. may be provided.

In the projection display device according to one embodiment of the present disclosure, the laser light source may include a light emitting section that emits laser light and a collimating lens that collimates the laser light emitted from the light emitting section.

In the projection display device according to one embodiment of the present disclosure, the diffractive optical element may include a plurality of element diffractive optical elements.

In the projection display device according to one embodiment of the present disclosure, the plurality of diffractive optical elements may include at least two diffractive optical elements having different angles of diffraction of light from the laser light source.

In the projection display device according to one embodiment of the present disclosure, the plurality of element diffractive optical elements includes at least two element diffractive optical elements having different radiation intensity distributions of light diffracted by the element diffractive optical elements. You can

The projection display device according to an embodiment of the present disclosure may further include a second optical system that shapes the light from the laser light source into a parallel beam.

The projection display device according to an embodiment of the present disclosure may further include a second optical system that widens the light from the laser light source and shapes it into a parallel beam.

A work device with a projection display device according to an embodiment of the present disclosure includes:
a work device that performs work while moving part or all of it;
the above-described projection type display device attached to the working device;
It has

ADVANTAGE OF THE INVENTION According to this invention, the projection-type display apparatus and working apparatus with a projection-type display apparatus which can brightly illuminate the area|region of a to-be-illuminated surface to some extent can be provided.

FIG. 1 is a diagram for explaining the first embodiment, and is a perspective view showing an example of a working device with a projection display device. FIG. 2 is a view corresponding to FIG. 1, and is a perspective view showing another example of the work device with a projection display device. FIG. 3 is a diagram schematically showing the overall configuration of the projection display device according to the first embodiment. FIG. 4 is a diagram schematically showing the overall configuration of a projection display device according to the second embodiment. FIG. 5 is a diagram schematically showing the overall configuration of a projection display device according to the third embodiment. FIG. 6 is a diagram schematically showing the overall configuration of a projection display device according to the fourth embodiment. FIG. 7 is a diagram schematically showing the overall configuration of a projection display device according to the fifth embodiment. FIG. 8 is a diagram schematically showing the overall configuration of a projection display device according to the sixth embodiment.

<First embodiment>
A first embodiment of the present disclosure will be described below with reference to the drawings. In the drawings attached to this specification, for the convenience of illustration and ease of understanding, the scale and the ratio of vertical and horizontal dimensions are changed and exaggerated from those of the real thing.

As used herein, terms specifying shapes and geometric conditions as well as degrees thereof, such as "parallel", "perpendicular", "identical", length and angle values, etc., are strictly It is interpreted to include the extent to which similar functions can be expected without limitation.

A work device 1 with a projection display device according to the present embodiment includes a work device 2 and a projection display device 10 . The work device 2 performs a specific work while moving part or all of it. Examples of the work device 2 include a work machine such as an automatic transport machine (see FIG. 1) that transports articles by pulling a cart, and a hydraulic excavator (see FIG. 2).

The projection-type display device 10 is attached to the working device 2 and illuminates an illuminated area 4 on an illuminated surface 3 around the working device 2 (for example, a road surface on which the working device 2 is installed) to display information. When the work device 2 is the automatic transport machine shown in FIG. Illuminated area 4 is illuminated to indicate a no-entry area. In this case, the illuminated area 4 having the shape of a curved line is displayed in front of the working device 2 in the traveling direction, and indicates that the working device 2 will stop when the working device 2 is closer than the illuminated area 4 . This suppresses the possibility that a person in the vicinity of the working device 2 unintentionally approaches the working device 2 and the working device 2 stops.

When the work device 2 is the hydraulic excavator shown in FIG. A shaped illuminated area 4 is illuminated to indicate a keep out area. In this case, the illuminated region 4 having the shape of a curved line is displayed at a position corresponding to the movable range of the bucket 5 and the arm 6 of the working device 2, and when the working device 2 is closer than the illuminated region 4, the working device 2 indicates that there is a risk of colliding with the bucket 5 or the arm 6. As a result, it is possible to prevent people around the working device 2 from unintentionally approaching the working device 2 and being injured.

In the example shown in FIGS. 1 and 2, the projection display device 10 illuminates the illuminated area 4 in the shape of a curved line, but the illumination is not limited to this. The projection display device 10 may illuminate the illuminated area 4 in the form of a straight line or a curved line. In addition, the projection display device 10 illuminates the illuminated area 4 in a shape representing at least one of bent lines, straight lines, curves, characters, patterns, color patterns, symbols, marks, illustrations, characters, and pictograms. good too. The projection display device 10 displays information related to the shape of the illuminated region 4 and the like on the illuminated surface 3 .

The place where the work device 2 is installed is not limited to the road surface, and the illuminated surface 3 illuminated by the projection display device 10 is not limited to the road surface. The work device 2 may be installed either outdoors or indoors. Further, the projection display device 10 may illuminate the ground other than the road surface, a floor surface, a water surface, a wall surface, or the like as the illuminated surface 3 . For example, the work device 2 may be installed in a sewage pipe, in which case the projection display device 10 may illuminate the walls of the sewage pipe.

In the example shown in FIG. 3, the projection display device 10 includes a laser light source 20, a diffractive optical element 30 that diffracts the light from the laser light source 20, and a first optical system that acts on the light emitted from the diffractive optical element 30. 40 and The projection display device 10 projects the light diffracted by the diffractive optical element 30 onto the illuminated surface 3 . The shape of the illuminated region 4 illuminated by the projection display device 10 is a shape corresponding to the diffraction pattern of the diffractive optical element 30 . In other words, the projection display device 10 displays information corresponding to the diffraction pattern of the diffractive optical element 30 on the illuminated surface 3 .

The laser light source 20 includes a light emitting section 21 that oscillates laser light. The laser light emitted from the light emitting section 21 has high directivity. Therefore, the laser light source 20 is suitable for the projection display device 10 that illuminates the illuminated surface 3 that is some distance away from the projection display device 10 . A semiconductor laser can be exemplified as the light emitting unit 21 . In the example shown in FIG. 3, the laser light source 20 includes a single light emitter 21. In the example shown in FIG. Therefore, in the example shown in FIG. 3 , the illuminated region 4 is illuminated with laser light of a color corresponding to the wavelength range of the laser light emitted from the laser light source 20 .

The diffractive optical element 30 changes the traveling direction of light from the laser light source 20 . The diffractive optical element 30 diffracts the light from the laser light source 20 and directs it to the first optical system 40 . The first optical system 40 acts on the light diffracted by the diffractive optical element 30 and directs the light toward the illuminated region 4 on the illuminated surface 3 . As a result, the illuminated area 4 is illuminated in a shape corresponding to the diffraction pattern of the diffractive optical element 30 .

The diffractive optical element 30 may be a hologram element. By using a hologram element as the diffractive optical element 30, the diffraction characteristics of the diffractive optical element 30 can be easily designed. It is possible to design a hologram element capable of projecting light only on the entire desired area having a predetermined position, outline shape, size, and orientation on the illuminated surface 3 . A region to be illuminated with light on the illuminated surface 3 is an illuminated region 4 .

When designing the diffractive optical element 30, the illuminated region 4 is set in real space at a predetermined position with respect to the diffractive optical element 30, with a predetermined contour shape, size and orientation. The position, contour shape, size and direction of the illuminated area 4 on the illuminated surface 3 depend on the diffraction characteristics of the diffractive optical element 30 . By adjusting the diffraction characteristics of the diffractive optical element 30, the position, outline shape, size and orientation of the illuminated region 4 on the illuminated surface 3 can be arbitrarily adjusted. Therefore, when designing the diffractive optical element 30, first, the position, contour shape, size and orientation of the illuminated region 4 on the illuminated surface 3 are determined. Next, the diffraction characteristics of the diffractive optical element 30 may be adjusted so that the light can be projected over the determined area 4 to be illuminated.

The diffractive optical element 30 can be produced as a computer generated hologram (CGH). A computer-generated hologram is created by calculating a structure with arbitrary diffraction characteristics on a computer. Therefore, by employing a computer-generated hologram as the diffractive optical element 30, generation of object light and reference light using a light source and an optical system and recording of interference fringes on a hologram recording material by exposure can be eliminated. The projection-type display device 10 is assumed to irradiate laser light onto an illuminated region 4 having a predetermined contour shape, size and direction at a predetermined position with respect to the projection-type display device 10 . By inputting information about the illuminated area 4 into the computer as a parameter, a structure having a diffraction characteristic, such as an uneven surface, capable of projecting the diffracted light onto the illuminated area 4 can be specified by computation in the computer. By forming the specified structure by resin molding, for example, the diffractive optical element 30 as a computer-generated hologram can be produced in a simple procedure at low cost.

An iterative Fourier transform method, for example, may be used to design the diffractive optical element 30 . When the iterative Fourier transform method is used, processing may be performed on the assumption that the illuminated area 4 is some distance away from the diffractive optical element 30, and the image projected onto the illuminated surface 3 may be the Fraunhofer diffraction image. Therefore, the illuminated surface 3 may be non-parallel to the diffractive surface of the diffractive optical element 30 .

In the example shown in FIG. 3, the diffractive optical element 30 includes multiple element diffractive optical elements 31 and 32 . The individual diffractive optical elements 31 and 32 are, for example, hologram elements, and can be constructed in the same manner as the diffractive optical element 30 described above.

Each element diffractive optical element 31, 32 may be configured to have the same diffraction characteristics. However, in order to realize projection with higher accuracy, each of the element diffractive optical elements 31 and 32 is designed separately according to the arrangement position of the element diffractive optical elements 31 and 32 in the diffractive optical element 30. It may be given properties.

For example, the diffraction characteristics of the individual diffractive optical elements 31 and 32 may be designed to control the incident angle and radiation intensity distribution of light incident on each position of the illuminated area 4 from the projection display device 10 . Thereby, the shape and size of the illuminated region 4 can be adjusted with higher accuracy. Further, this makes it possible to adjust the irradiance at each position of the illuminated region 4 with higher accuracy, and for example, to illuminate the illuminated region 4 with uniform brightness. Here, the irradiance refers to the amount of light received per unit area, that is, the received light energy.

By the way, according to the projection type display apparatus using the diffraction optical element, the area to be illuminated can be illuminated in a shape corresponding to the diffraction pattern of the diffraction optical element by the diffraction of the diffraction optical element. However, in the diffractive optical element, in addition to the first-order diffracted light, second-order and higher-order diffracted light (hereinafter also referred to as "high-order diffracted light") is generated. Also, part of the light from the light source passes through the diffractive optical element without being diffracted by the diffractive optical element, and becomes so-called zero-order light. As the diffraction angle range of the diffractive optical element widens, the intensity of 0th-order light increases and the intensity of high-order diffracted light increases. An increase in the intensity of the 0th order light compromises the laser safety of projection displays. Further, when the intensity of the high-order diffracted light increases, a diffraction image (so-called "flare") due to the high-order diffracted light becomes visible on the irradiated surface in addition to the diffraction image due to the first-order diffracted light. Furthermore, when the intensity of the zero-order light and the high-order diffracted light increases, it is impossible to brightly illuminate the illuminated area.

In order to solve such a problem, it is conceivable to dispose a mask for blocking 0th-order light and high-order diffracted light between the diffractive optical element and the surface to be irradiated. However, in this case, the utilization efficiency of the light from the light source is lowered.

Considering this point, in the illustrated example, the diffractive optical element 30 has a light diffraction angle of 0±15° or less, preferably 0±10° or less, more preferably 0±5° or less. designed to be. By setting the diffraction angle of the diffractive optical element 30 within the above range, it is possible to suppress an increase in the intensity of the 0th-order light and high-order diffracted light, and to clearly illuminate the region 4 to be illuminated.

Next, the first optical system 40 will be explained. The first optical system 40 includes a first lens group 41 and a second lens group 42 . The second lens group 42 is arranged downstream of the first lens group 41 in the optical path of the light from the laser light source 20 . The first lens group 41 is a lens group into which light diffracted by the diffractive optical element 30 is incident, and has positive power. The second lens group 42 is a lens group into which light emitted from the first lens group 41 is incident, and has negative power. The first optical system 40 reduces the optical path width of the light incident on the first optical system 40 by the first lens group 41 and widens it by the second lens group 42 . As a result, blurring of the illuminated area 4 due to the beam diameter of the laser light emitted from the laser light source 20 can be suppressed, and the illuminated area 4 can be clearly illuminated. Specifically, in the example shown in FIG. 3 , the blurred region in the illuminated region 4 is the region indicated by reference numeral 90 . This region 90 is significantly smaller than the blurred region that occurs when the diffracted light from the diffractive optical element 30 is directly incident on the surface to be illuminated 3 without being affected by the first optical system 40 .

The first lens group 41 and the second lens group 42 may each be composed of a single lens, or may be composed of a plurality of lenses. In one embodiment shown in FIG. 3, the first lens group 41 consists of a single convex lens 43 . Also, the second lens group 42 is composed of a single concave lens 44 .

In the example shown in FIG. 3, the convex lens 43 forming the first lens group 41 and the concave lens 44 forming the second lens group 42 are arranged such that their optical axes are aligned on the same straight line. The rear focus of the convex lens 43 forming the first lens group 41 is arranged to coincide with the front focus of the concave lens 44 forming the second lens group 42 . By forming the first optical system 40 in this way, the lights that are emitted from different points on the exit surface of the diffractive optical element 30 and enter the first optical system 40 are converted into parallel or substantially parallel light beams as first light beams. It can be emitted from the optical system 40 . Therefore, it is suppressed that the size of the blurred region 90 of the illuminated region 4 changes depending on the distance between the projection display device 10 and the illuminated surface 3 . In other words, the existence of the first optical system 40 suppresses the expansion of the blurred region 90 of the illuminated region 4 as the illuminated surface 3 moves away from the projection display device 10 .

Note that the first optical system 40 shown in FIG. 3 can be designed so that when a parallel light beam is incident, it can be emitted as a parallel light beam. That is, the first optical system 40 shown in FIG. 3 can function as an afocal optical system when a parallel beam is incident.

Also, in the example shown in FIG. 3, the angular magnification of the first optical system 40 is greater than one. As a result, the light emitted from the first optical system 40 diverges as a whole. As a result, even when the surface to be illuminated 3 is at a relatively short distance from the projection display device 10, the surface to be illuminated 3 can be illuminated in a wide range.

Further, when the distance between the projection display device 10 and the illuminated area 4 is predetermined, by designing the diffraction characteristics of the diffractive optical element 30 (individual diffractive optical elements 31 and 32), it is possible to reduce blurring. region 90 can be further suppressed.

<Second embodiment>
Next, a second embodiment of the present disclosure will be described with reference to FIG. A projection display apparatus 10A shown in FIG. 4 differs from the projection display apparatus 10 shown in FIG. Other configurations are substantially the same as those of the projection display device 10 shown in FIG. In the second embodiment shown in FIG. 4, parts similar to those of the projection display apparatus 10 shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The second optical system 50 is arranged between the laser light source 20 and the diffractive optical element 30 on the optical path of light from the laser light source 20 . The second optical system 50 shapes the diffused light emitted from the laser light source 20 so that it approaches a parallel light beam. In the illustrated example, the second optical system 50 is composed of a collimator lens, and collimates the laser light emitted from the laser light source 20 to bring it closer to a parallel light beam. As a result, the collimated light enters the diffractive optical element 30, so that the diffractive optical element 30 can diffract the light in a desired direction with high accuracy.

The second optical system 50 is arranged at a position sufficiently distant from the laser light source 20 . Therefore, sufficiently diffused light source light is collimated by the second optical system 50 . As a result, the light collimated by the second optical system 50 can enter a wide area of the diffractive optical element 30 and illuminate the surface 3 to be illuminated widely.

<Third Embodiment>
Next, a third embodiment of the present disclosure will be described with reference to FIG. A projection display device 10B shown in FIG. 5 differs from the projection display device 10 shown in FIG. Another difference is that the projection type display device 10B includes a scanning device 60 . Other configurations are substantially the same as those of the projection display device 10 shown in FIG. In the third embodiment shown in FIG. 5, parts similar to those of the projection display apparatus 10 shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

The collimating lens 22 is arranged downstream of the light emitting section 21 in the optical path of the light from the light emitting section 21 . The collimator lens 22 collimates the laser light emitted by the light emitting unit 21 to bring it closer to a parallel light flux. As a result, collimated light is emitted from the laser light source 20B and enters the diffractive optical element 30 . Therefore, the diffractive optical element 30 can diffract light in a desired direction with high accuracy.

A collimating lens 22 of the laser light source 20B is arranged near the light emitting section 21 . Therefore, the diffusion of the laser light emitted from the laser light source 20B can be suppressed, and the blurring of the illuminated region 4 caused by the beam diameter of the light can be suppressed.

Next, the scanning device 60 will be described. The scanning device 60 scans the light on the diffraction optical element 30 by changing the optical path of the laser light from the laser light source 20B over time. As a result, the incident position of the laser light moves on the diffractive optical element 30 . That is, the diffractive optical element 30 into which the laser light from the laser light source 20 is incident changes between the plurality of element diffractive optical elements 31 and 32 . The illustrated scanning device 60 has a reflective surface that is rotatable about an axis RA. A MEMS mirror or a galvanomirror may be used as such a scanning device 60 .

In the example shown in FIG. 5, the plurality of diffractive optical elements 31 and 32 may diffract light from the light source and emit light beams with different profiles (especially contours). In this case, the shape of the illuminated area 4 can be changed according to the incident position of the light on the diffractive optical element 30 .

Also, in the example shown in FIG. 5, the light diffracted by the plurality of diffractive optical elements 31 and 32 may be directed to different illuminated areas 4a and 4b. In this case, the diffraction angle range of the light diffracted by each element diffractive optical element 31, 32 can be narrowed. Further, in this case, the illuminated area can be moved between the illuminated area 4 a and the illuminated area 4 b according to the incident position of the light on the diffractive optical element 30 .

It should be noted that since the scanning device 60 operates at a speed exceeding the resolution of human vision, it appears to the human eye that all illuminated regions 4a and 4b are continuously illuminated at the same time. Therefore, in this case, the illumination region 4 of the projection display device 10B is the sum of all the illuminated regions 4a and 4b. In particular, in the example shown in FIG. 5, since the laser light source 20B has the collimating lens 22, the beam diameter of the light from the laser light source 20B is reduced compared to the projection display devices 10 and 10A shown in FIGS. While the resulting blurring of the illuminated regions 4a and 4b can be suppressed, the light incident region on the diffractive optical element 30 at each time point is narrow. However, by changing the incident position of light on the diffractive optical element 30 while operating the scanning device 60 at a speed exceeding the resolution of human vision, the projection display devices 10 and 10A shown in FIGS. It is possible to illuminate an area to be illuminated 4 having a size similar to that of .

<Fourth Embodiment>
Next, a fourth embodiment of the present disclosure will be described with reference to FIG. A projection display device 10C shown in FIG. 6 differs from the projection display device 10B shown in FIG. 5 in that it has a second optical system 50C. Other configurations are substantially the same as those of the projection display device 10B shown in FIG. In the fourth embodiment shown in FIG. 6, parts similar to those of the projection display apparatus 10B shown in FIG.

The second optical system 50</b>C is arranged between the scanning device 60 and the diffractive optical element 30 along the optical path from the laser light source 20</b>B to the diffractive optical element 30 . The second optical system 50C widens the light emitted from the laser light source 20B and shapes it into a parallel light beam. In the example shown in FIG. 6, the second optical system 50C has a lens 51 and a collimating lens 52 in order along the optical path of the light emitted from the laser light source 20B. The lens 51 shapes the light emitted from the laser light source 20B into a divergent luminous flux. The collimator lens 52 reshapes the divergent light flux generated by the lens 51 into a parallel light flux.

By disposing the second optical system 50C between the scanning device 60 and the diffractive optical element 30, the scanning width of the light that scans the incident surface of the diffractive optical element 30 can be expanded. This makes it possible to illuminate larger areas to be illuminated 4a and 4b compared to the projection display device 10B shown in FIG. In addition, since the light collimated by the second optical system 50C enters the diffractive optical element 30, the diffractive optical element 30 can diffract the light in a desired direction with high accuracy.

The scanning device 60 may control whether or not the laser light is supplied to the diffractive optical element 30 .

<Fifth Embodiment>
Next, a fifth embodiment of the present disclosure will be described with reference to FIG. In a projection display device 10D shown in FIG. 7, unlike the projection display device 10C shown in FIG. It is different in that it forms Other configurations are substantially the same as those of the projection display device 10C shown in FIG. In the fifth embodiment shown in FIG. 7, parts similar to those of the projection display apparatus 10C shown in FIG. 6 are assigned the same reference numerals, and detailed description thereof will be omitted.

In the example shown in FIG. 7, the first optical system 40D directs the light diffracted by each of the plurality of elemental diffractive optical elements 31 and 32 forming the diffractive optical element 30 onto a plane at a predetermined distance from the projection display device 10D. An imaging optical system for imaging is formed. The first optical system 40D forms an image of the light diffracted by the diffractive optical element 30 on a surface downstream of the first optical system 40D in the optical path of the light from the laser light source 20. FIG. In this case, if the distance between the projection display device 10D and the surface to be illuminated 3 is matched with the predetermined distance, or if the distance between the projection display device 10D and the surface to be illuminated 3 is brought close to the predetermined distance, Blurring of the illuminated area 4 due to the beam diameter of the laser light emitted from the laser light source 20B can be suppressed extremely effectively. As a result, the illuminated region 4 can be illuminated very sharply.

Alternatively, in this case, if the distance between the projection display device 10D and the surface to be illuminated 3 is made equal to the predetermined distance, or the distance between the projection display device 10D and the surface to be illuminated 3 is brought close to the above predetermined distance. For example, it is possible to suppress the movement of the illuminated areas 4a and 4b according to the change in the incident position of the light on the diffractive optical element 30 by the scanning device 60. FIG.

In the example shown in FIG. 7, when the image projected onto the illuminated surface 3 is a Fraunhofer diffraction image, the image formed by the first optical system 40D is a Fourier transform image.

<Sixth embodiment>
Next, a sixth embodiment of the present disclosure will be described with reference to FIG. Compared to the projection display device 10C shown in FIG. 6, in the projection display device 10E shown in FIG. 8, the image of the light emitted from the projection display device 10E is blurred at a predetermined distance from the projection display device 10E. The difference is that the diffractive optical element 30E is designed to be the smallest on the surface. Other configurations are substantially the same as those of the projection display device 10C shown in FIG. In the sixth embodiment shown in FIG. 8, parts similar to those of the projection display apparatus 10C shown in FIG. 6 are assigned the same reference numerals, and detailed description thereof will be omitted.

In the example shown in FIG. 8, the diffraction angle of each of the plurality of elemental diffraction optical elements 31e and 32e forming the diffraction optical element 30E is the same as that of the blurred region of the illuminated region 4 on a plane at a predetermined distance from the projection display device 10E. It is determined that 90 is the smallest. In the example shown in FIG. 8, the light diffracted by the diffractive optical element 30E enters the first optical system 40, which is a non-imaging optical system. is incident on the illuminated surface 3 on the downstream side of . In this case, if the distance between the projection display device 10E and the surface to be illuminated 3 is matched with the predetermined distance, or if the distance between the projection display device 10E and the surface to be illuminated 3 is brought close to the predetermined distance, Blurring of the illuminated area 4 due to the beam diameter of the laser light emitted from the laser light source 20B can be suppressed extremely effectively. As a result, the illuminated region 4 can be illuminated very sharply.

Alternatively, in this case, if the distance between the projection display device 10E and the surface to be illuminated 3 is matched with the predetermined distance, or the distance between the projection display device 10E and the surface to be illuminated 3 is made close to the predetermined distance. For example, it is possible to suppress the movement of the illuminated areas 4a and 4b in accordance with the change in the incident position of the light on the diffractive optical element 30E by the scanning device 60. FIG.

Furthermore, in this case, as shown in FIG. 8, the diffraction optical element 30E can be designed such that the surface at the predetermined distance is inclined with respect to the optical axis of the first optical system 40. FIG. Specifically, by making the angles of diffraction of light at the plurality of diffractive optical elements 31e and 32e different from each other, the light is diffracted at the diffractive optical element 30E on a surface inclined with respect to the optical axis of the first optical system 40. The blurring of the optical image due to the emitted light can be suppressed most effectively. In this case, even if the surface to be illuminated 3 is inclined with respect to the optical axis of the first optical system 40, it is possible to obtain the above-described effects of suppressing blurring of the illuminated region 4 and suppressing movement of the illuminated region. .

In the first to sixth embodiments described above, the projection display devices 10 to 10E include a laser light source 20; 20B, a diffraction optical element 30; 30E that diffracts the light emitted from the laser light source 20; and a first optical system 40; 40D provided on the optical path of the light diffracted by the diffractive optical element 30; 30E. The first optical system 40; 40D includes a first lens group 41 having a positive power into which light diffracted by the diffraction optical element 30; 30E enters, and a negative power into which the light emitted from the first lens group 41 enters. and a second lens group 42 with power. The angular magnification of the first optical system 40 is greater than one. According to the projection display devices 10 to 10E, blurring of the illuminated area 4 caused by the beam diameter of the laser light emitted from the laser light source 20 can be suppressed, and the illuminated area 4 can be clearly illuminated. can do. In addition, it is possible to illuminate a relatively wide area of the illuminated surface 3, which is located at a relatively short distance from the projection display devices 10 to 10E.

Further, in the first to sixth embodiments described above, the diffraction angle of light at the diffractive optical elements 30; 30E is 0±15° or less. As a result, it is possible to suppress an increase in the intensity of the zero-order light and the high-order diffracted light, and to clearly illuminate the illuminated region 4 .

Also, in the fifth embodiment described above, the first optical system 40D forms an imaging optical system. As a result, blurring of the illuminated area 4 due to the beam diameter of the laser light emitted from the laser light source 20B can be suppressed extremely effectively, and the illuminated area 4 can be illuminated extremely sharply.

In the first to fourth and sixth embodiments described above, the optical axes of the first lens group 41 and the second lens group 42 are arranged on the same straight line. and so that the rear focal point of the first lens group 41 coincides with the front focal point of the second lens group 42 . As a result, particularly in the first to fourth embodiments, it is suppressed that the blurred region of the illuminated region 4 expands as the illuminated surface 3 is separated from the projection display devices 10 to 10C and 10E.

Further, in the third to sixth embodiments described above, the projection display devices 10B to 10E change the direction of travel of the light emitted from the laser light source 20B, so that the light from the laser light source 20B is diffracted optically. It further comprises a scanning device 60 for scanning over the elements 30; 30E. Thereby, the optical path of the laser beam emitted by the laser light source 20B is adjusted to control the allocation of the laser beam to the plurality of elemental diffraction optical elements 31, 32; 31e, 32e constituting the diffraction optical elements 30; 30E. be able to. Further, the scanning device 60 can also control whether or not laser light is supplied to the diffractive optical elements 30; 30E.

In the third to sixth embodiments described above, the laser light source 20B includes the light emitting section 21 that oscillates laser light and the collimating lens 22 that collimates the laser light from the light emitting section 21. As a result, blurring of the illuminated regions 4a and 4b due to the beam diameter of the light from the laser light source 20B can be suppressed. In addition, since the collimated light is incident on the diffractive optical element 30, the diffractive optical element 30 can diffract the light in a desired direction with high accuracy.

Moreover, in the first to sixth embodiments described above, the diffractive optical element 30; 30E includes a plurality of element diffractive optical elements 31, 32; 31e, 32e. As a result, the diffraction angle range of the light diffracted by each element diffraction optical element 31, 32; 31e, 32e can be narrowed. As a result, it is possible to suppress an increase in the intensity of the 0th-order light and the high-order diffracted light, and to clearly illuminate the region 4 to be illuminated.

In addition, in the first to sixth embodiments described above, the plurality of element diffractive optical elements 31, 32; , 32; 31e, 32e. This makes it possible to clearly illuminate the illuminated area 4 on the illuminated surface 3 tilted with respect to the optical axis of the first optical system 40 .

Moreover, in the first to sixth embodiments described above, the plurality of diffractive optical elements 31, 32; It includes element diffractive optical elements 31, 32; 31e, 32e. Thereby, the irradiance at each position of the illuminated region 4 can be adjusted with higher accuracy, and for example, the illuminated region 4 can be illuminated with uniform brightness.

Further, in the second embodiment described above, the projection display device 10A further includes the second optical system 50 that shapes the light from the laser light source 20 into a parallel beam. As a result, the collimated light enters the diffractive optical element 30, so that the diffractive optical element 30 can diffract the light in a desired direction with high accuracy.

Further, in the fourth to sixth embodiments described above, the projection display devices 10C to 10E further include a second optical system 50C that widens the light from the laser light source 20B and shapes it into a parallel beam. Thereby, a wide area of the diffractive optical elements 30; 30E can be illuminated, and the illuminated surface 3 can be illuminated in a wide range. In addition, since the collimated light is incident on the diffractive optical element 30, the diffractive optical element 30 can diffract the light in a desired direction with high accuracy.

Further, in the first to sixth embodiments described above, the work device 1 with a projection display device includes the work device 2 that performs work while being partially or entirely moved, and the work device 2 that is attached to the work device 2. and projection display devices 10 to 10E. According to the working device 1 with such a projection display device, it is possible to clearly illuminate a relatively wide area of the illuminated surface 3 and display desired information around the working device 2 .

Although several modifications of the above-described embodiment have been described above, it is of course possible to apply a plurality of modifications in appropriate combination.

1 Work device with projection display device 2 Work device 3 Surface to be illuminated 4 Areas to be illuminated 10 to 10E Projection display devices 20, 20B Laser light source 21 Light emitting unit 22 Collimating lenses 30, 30E Diffractive optical elements 31, 32, 31e, 32e Element diffraction optical elements 40, 40D First optical system 50, 50C Second optical system 60 Scanning device

Claims (12)

a laser light source;
a diffractive optical element that diffracts light emitted from the laser light source;
a first optical system provided on the optical path of the light diffracted by the diffractive optical element;
with
The first optical system is
a first lens group having a positive power into which the light diffracted by the diffractive optical element is incident;
a second lens group having negative power into which the light emitted from the first lens group is incident;
including
A projection display device, wherein the angular magnification of the first optical system is greater than 1. 2. The projection display device according to claim 1, wherein the diffraction angle of the light at the diffractive optical element is 0±15° or less. 3. The projection display device according to claim 1, wherein said first optical system forms an imaging optical system. The first lens group and the second lens group are arranged such that the optical axes of the first lens group and the second lens group are aligned on the same straight line, and the rear focal point of the first lens group is the 4. The projection display apparatus according to any one of claims 1 to 3, arranged so as to match the front focal point of the second lens group. 5. The apparatus according to any one of claims 1 to 4, further comprising a scanning device that scans the diffractive optical element with the light emitted from the laser light source by changing the traveling direction of the light emitted from the laser light source. A projection display device as described. 6. The projection display device according to claim 1, wherein said laser light source includes a light emitting section that oscillates laser light, and a collimating lens that collimates said laser light emitted from said light emitting section. 7. The projection display apparatus according to any one of claims 1 to 6, wherein said diffractive optical element includes a plurality of element diffractive optical elements. 8. The projection display apparatus according to claim 7, wherein said plurality of diffractive optical elements include at least two diffractive optical elements having different angles of diffraction of light from said laser light source. 8. The projection display apparatus according to claim 7, wherein said plurality of elemental diffractive optical elements include at least two elemental diffractive optical elements having different radiation intensity distributions of light diffracted by said elemental diffractive optical elements. 10. The projection display device according to any one of claims 1 to 9, further comprising a second optical system for shaping light from said laser light source into a parallel beam. 10. The projection display device according to any one of claims 1 to 9, further comprising a second optical system that widens the light from the laser light source and shapes it into a parallel light beam. a work device that performs work while moving part or all of it;
a projection display device according to any one of claims 1 to 11, which is attached to the working device;
A working device with a projection type display device.

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