Projection display device and working device

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

[Technical Field]

[0001] The present invention relates to a projection display device and a working device equipped with a projection display device. [Background technology]

[0002] For example, working devices such as those disclosed in Patent Documents 1 and 2 are used in various fields. The working devices perform some work while moving the whole or part of them. Examples of working devices include automatic conveying machines that tow carts to transport objects, and working machines such as hydraulic excavators.

[0003] Recently, there has been a demand for labor-saving and automation in the use of work equipment. For this reason, it is desirable to equip the work equipment with a display device that alerts people around the work equipment. The display device notifies people around the work equipment of the approach of the work equipment and the movable range of the work equipment while the work equipment is in operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-98674 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-081017 Summary of the Invention [Problem to be solved by the invention]

[0005] As such a display device, a projection display device that displays by illuminating the road surface or floor surface on which the working device is placed is being considered. When a projection display device is used to display information about the approach of the working device or the movable area, the projection display device mounted on the working device needs to clearly illuminate a fairly wide area of ​​the road surface or floor surface on which the working device is placed (hence, the illuminated surface that is at a certain distance from the projection display device).

[0006] 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. [Means for solving the problem]

[0007] A projection display device according to an embodiment of the present disclosure includes: A laser light source; a diffractive optical element that diffracts the light emitted from the laser light source; a first optical system provided on an optical path of light diffracted by the diffractive optical element; Equipped with The first optical system is a first lens group having positive power onto which light diffracted by the diffractive optical element is incident; a second lens group having negative power onto which light emitted from the first lens group is incident; Including, The first optical system has an angular magnification greater than 1.

[0008] In the projection display device according to the embodiment of the present disclosure, the diffraction angle of the light at the diffractive optical element may be 0±15° or less.

[0009] In the projection display device according to the embodiment of the present disclosure, the first optical system may form an imaging optical system.

[0010] In a projection display device according to one embodiment of the present disclosure, the first lens group and the second lens group may be arranged so that the optical axes of the first lens group and the second lens group are aligned on the same straight line, and so that the rear focus of the first lens group coincides with the front focus of the second lens group.

[0011] A projection display device according to an embodiment of the present disclosure may further include a scanning device that scans the light from the laser light source on the diffractive optical element by changing the direction of travel of the light emitted from the laser light source.

[0012] In the projection display device according to the embodiment of the present disclosure, the laser light source may include a light emitting unit that oscillates laser light, and a collimating lens that collimates the laser light from the light emitting unit.

[0013] In the projection display device according to the embodiment of the present disclosure, the diffractive optical element may include a plurality of element diffractive optical elements.

[0014] In the projection display device according to the embodiment of the present disclosure, the plurality of element diffractive optical elements may include at least two element diffractive optical elements that have different diffraction angles of light from the laser light source.

[0015] In a projection display device according to an embodiment of the present disclosure, the plurality of element diffractive optical elements may include at least two element diffractive optical elements having different radiation intensity distributions of light diffracted by the element diffractive optical elements.

[0016] The projection display device according to the 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.

[0017] The projection display device according to the embodiment of the present disclosure may further include a second optical system that widens the light from the laser light source and shapes the light into a parallel beam.

[0018] A working device with a projection-type display device according to an embodiment of the present disclosure includes: A work device that performs work while moving a part or the whole of the work device; the projection type display device described above attached to the working device; It is equipped with: [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a projection type display device and a working device equipped with a projection type display device that can clearly illuminate a relatively wide area of ​​the illuminated surface. [Brief explanation of the drawings]

[0020] [Figure 1] 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 type display device. [Figure 2] FIG. 2 is a view corresponding to FIG. 1 and is a perspective view showing another example of a working device with a projection type display device. [Figure 3] FIG. 3 is a diagram schematically showing the overall configuration of the projection display device according to the first embodiment. [Figure 4] FIG. 4 is a diagram schematically showing the overall configuration of a projection display device according to the second embodiment. [Figure 5] FIG. 5 is a diagram schematically showing the overall configuration of a projection display device according to the third embodiment. [Figure 6] FIG. 6 is a diagram schematically showing the overall configuration of a projection display device according to a fourth embodiment. [Figure 7] FIG. 7 is a diagram schematically showing the overall configuration of a projection display device according to a fifth embodiment. [Figure 8] FIG. 8 is a diagram schematically showing the overall configuration of a projection display device according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] First Embodiment Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. Note that in the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding.

[0022] Terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "perpendicular," and "same," as well as values ​​of lengths and angles, are not limited to their strict meanings, but are interpreted to include a range within which similar functions can be expected.

[0023] The working device 1 with a projection display device in this embodiment includes a working device 2 and a projection display device 10. The working device 2 performs a specific task while moving a part or the whole of it. Examples of the working device 2 include an automatic transport vehicle (see FIG. 1) that pulls a cart to transport goods, and a working machine such as a hydraulic excavator (see FIG. 2).

[0024] The projection display device 10 is attached to the operating device 2 and displays information by illuminating an illuminated area 4 on an illuminated surface 3 around the operating device 2 (for example, the road surface on which the operating device 2 is installed). When the operating device 2 is the automatic transport vehicle shown in FIG. 1, the projection display device 10, for example, treats the road surface on which the operating device 2 moves as the illuminated surface 3, and illuminates an illuminated area 4 in the shape of a curved line on the illuminated surface 3 to indicate a no-entry area. In this case, the illuminated area 4 in the shape of a curved line is displayed ahead in the traveling direction of the operating device 2, and indicates that the operating device 2 will stop if it gets closer to the operating device 2 than the illuminated area 4. This reduces the risk that someone around the operating device 2 will unintentionally approach the operating device 2, causing it to stop.

[0025] 2, the projection display device 10, for example, sets the road surface on which the work device 2 is installed as the illuminated surface 3, and illuminates an illuminated area 4 in the shape of a curved line on the illuminated surface 3 to indicate a no-entry area. In this case, the illuminated area 4 in the shape of a curved line is displayed in a position corresponding to the range of motion of the bucket 5 and arm 6 of the work device 2, indicating that if someone gets closer to the work device 2 than the illuminated area 4, there is a risk of collision with the bucket 5 or arm 6 of the work device 2. This reduces the risk of people around the work device 2 unintentionally approaching the work device 2 and getting injured.

[0026] 1 and 2, the projection display device 10 illuminates the illuminated area 4 in the shape of a curved line, but this is not limited to this. The projection display device 10 may illuminate the illuminated area 4 in the shape of a straight line or a curved line. The projection display device 10 may also illuminate the illuminated area 4 in a shape representing one or more of a curved line, straight line, curved line, character, picture, color pattern, symbol, mark, illustration, character, and pictogram. The projection display device 10 displays information related to the shape of the illuminated area 4, etc., on the illuminated surface 3.

[0027] The location where the working 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 working device 2 may be installed either outdoors or indoors. The projection display device 10 may also illuminate the illuminated surface 3 as the ground surface other than the road surface, a floor surface, a water surface, a wall surface, etc. For example, the working device 2 may be installed inside a sewer pipe, and in this case, the projection display device 10 may illuminate the wall surface of the sewer pipe.

[0028] 3, the projection display device 10 includes a laser light source 20, a diffractive optical element 30 that diffracts light from the laser light source 20, and a first optical system 40 that acts on the light emitted from the diffractive optical element 30. The projection display device 10 projects the light diffracted by the diffractive optical element 30 onto an illuminated surface 3. The shape of the illuminated area 4 illuminated by the projection display device 10 corresponds 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.

[0029] The laser light source 20 includes a light-emitting unit 21 that emits laser light. The laser light emitted from the light-emitting unit 21 has high directivity. Therefore, the laser light source 20 is suitable for a projection display device 10 that illuminates an illuminated surface 3 that is some distance away from the projection display device 10. An example of the light-emitting unit 21 is a semiconductor laser. In the example shown in FIG. 3, the laser light source 20 includes a single light-emitting unit 21. Therefore, in the example shown in FIG. 3, the illuminated area 4 is illuminated with laser light of a color that corresponds to the wavelength range of the laser light emitted from the laser light source 20.

[0030] The diffractive optical element 30 changes the traveling direction of the light from the laser light source 20. The diffractive optical element 30 diffracts the light from the laser light source 20 and directs it toward 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 area 4 on the illuminated surface 3. As a result, the illuminated area 4 is illuminated in a shape according to the diffraction pattern of the diffractive optical element 30.

[0031] The diffractive optical element 30 may be a hologram element. Using a hologram element as the diffractive optical element 30 makes it easier to design the diffraction characteristics of the diffractive optical element 30. It is possible to design a hologram element that can project light only onto the entire desired area on the illuminated surface 3, which has a predetermined position, contour shape, size, and orientation. The area on the illuminated surface 3 that is illuminated with light becomes the illuminated area 4.

[0032] When designing the diffractive optical element 30, the illuminated area 4 is set in real space at a predetermined position relative to the diffractive optical element 30, with a predetermined contour shape, size, and orientation. The position, contour shape, size, and orientation 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, contour shape, size, and orientation of the illuminated area 4 on the illuminated surface 3 can be adjusted as desired. Therefore, when designing the diffractive optical element 30, the position, contour shape, size, and orientation of the illuminated area 4 on the illuminated surface 3 are first determined. Next, the diffraction characteristics of the diffractive optical element 30 are adjusted so that light can be projected over the entire illuminated area 4 that has been determined.

[0033] The diffractive optical element 30 can be fabricated as a computer-generated hologram (CGH). A computer-generated hologram is created by calculating a structure with desired diffraction characteristics on a computer. Therefore, using a computer-generated hologram as the diffractive optical element 30 eliminates the need to generate object and reference beams using a light source and optical system, or to record interference fringes on a hologram recording material by exposure. The projection display device 10 is designed to irradiate an illuminated area 4 with a predetermined contour shape, size, and orientation at a predetermined position relative to the projection display device 10 with laser light. By inputting information about the illuminated area 4 as parameters into a computer, a structure with diffraction characteristics capable of projecting diffracted light onto the illuminated area 4, such as a concave-convex surface, can be specified by computer calculation. By forming the specified structure, for example, by resin molding, the diffractive optical element 30 as a computer-generated hologram can be fabricated easily and at low cost.

[0034] The diffractive optical element 30 may be designed using, for example, an iterative Fourier transform method. When the iterative Fourier transform method is used, processing may be performed on the assumption that the illuminated region 4 is located at a certain distance from the diffractive optical element 30, and the image projected onto the illuminated surface 3 may be a Fraunhofer diffraction image. Therefore, the illuminated surface 3 may be non-parallel to the diffractive surface of the diffractive optical element 30.

[0035] 3, the diffractive optical element 30 includes a plurality of element diffractive optical elements 31 and 32. Each of the element diffractive optical elements 31 and 32 is, for example, a hologram element, and can be configured in the same manner as the diffractive optical element 30 described above.

[0036] The element diffractive optical elements 31 and 32 may be configured to have the same diffractive characteristics as each other. However, to achieve more accurate projection, each element diffractive optical element 31 and 32 may be given a diffractive characteristic that is individually designed depending on the arrangement position of the element diffractive optical element 31 and 32 within the diffractive optical element 30.

[0037] For example, the diffraction characteristics of the individual diffractive optical elements 31, 32 may be designed to control the angle of incidence and radiant intensity distribution of light incident from the projection display device 10 at each position in the illuminated area 4. This makes it possible to adjust the shape and size of the illuminated area 4 with higher precision. This also makes it possible to adjust the irradiance at each position in the illuminated area 4 with higher precision, making it possible to illuminate the illuminated area 4 with uniform brightness, for example. Here, irradiance refers to the amount of light received per unit area, i.e., the received light energy.

[0038] A projection display device using a diffractive optical element can illuminate an illuminated area in a shape corresponding to the diffraction pattern of the diffractive optical element by diffraction in the diffractive optical element. However, a diffractive optical element generates not only first-order diffracted light but also second-order or higher-order diffracted light (hereinafter also referred to as "higher-order diffracted light"). Furthermore, a portion of the light from the light source passes through the diffractive optical element without being diffracted, becoming so-called zeroth-order light. As the diffraction angle range of the diffractive optical element widens, the intensity of the zeroth-order light and the intensity of the higher-order diffracted light increase. The increased intensity of the zeroth-order light compromises the laser safety of the projection display device. Furthermore, as the intensity of the higher-order diffracted light increases, diffracted images (so-called "flare") due to the higher-order diffracted light become visible on the illuminated surface in addition to the diffracted image due to the first-order diffracted light. Furthermore, the increased intensity of the zeroth-order light and the higher-order diffracted light makes it difficult to illuminate the illuminated area brightly.

[0039] To solve this problem, it is conceivable to place a mask between the diffractive optical element and the illuminated surface to block the zeroth-order and higher-order diffracted light, but this would reduce the efficiency of light utilization from the light source.

[0040] Taking this into consideration, in the illustrated example, the diffractive optical element 30 is designed so that the diffraction angle of its light is 0±15° or less, preferably 0±10° or less, and more preferably 0±5° or less. When the diffraction angle of the diffractive optical element 30 is within the above range, an increase in the intensity of the zeroth-order light and higher-order diffracted light can be suppressed, and the illuminated area 4 can be clearly illuminated.

[0041] Next, the first optical system 40 will be described. The first optical system 40 includes a first lens group 41 and a second lens group 42. The second lens group 42 is located 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 onto which light diffracted by the diffractive optical element 30 is incident and has positive optical power. The second lens group 42 is a lens group onto which light emitted from the first lens group 41 is incident and has negative optical power. The first optical system 40 reduces the optical path width of the light incident on the first optical system 40 with the first lens group 41 and widens it with the second lens group 42. This makes it possible to suppress blurring of the illuminated area 4 caused by the beam diameter of the laser light emitted from the laser light source 20, thereby enabling the illuminated area 4 to be clearly illuminated. Specifically, in the example shown in FIG. 3 , the area of ​​the illuminated area 4 where blurring occurs is the area indicated by reference numeral 90. This area 90 is significantly smaller than the area of ​​blur that occurs when the diffracted light from the diffractive optical element 30 is incident directly on the illuminated surface 3 without being affected by the first optical system 40 .

[0042] Each of the first lens group 41 and the second lens group 42 may be composed of a single lens or multiple lenses. In the specific example shown in Figure 3, the first lens group 41 is composed of a single convex lens 43. The second lens group 42 is composed of a single concave lens 44.

[0043] In the example shown in FIG. 3 , the convex lens 43 constituting the first lens group 41 and the concave lens 44 constituting the second lens group 42 are arranged so that their optical axes are aligned on the same line. The convex lens 43 constituting the first lens group 41 is arranged so that the rear focal point of the convex lens 43 coincides with the front focal point of the concave lens 44 constituting the second lens group 42. By configuring the first optical system 40 in this manner, light beams emitted from different points on the exit surface of the diffractive optical element 30 and incident on the first optical system 40 can be emitted from the first optical system 40 as parallel or approximately parallel beams. This prevents the size of the blurred region 90 in the illuminated area 4 from changing depending on the distance between the projection display device 10 and the illuminated surface 3. In other words, the presence of the first optical system 40 prevents the blurred region 90 in the illuminated area 4 from expanding as the illuminated surface 3 becomes farther away from the projection display device 10.

[0044] The first optical system 40 shown in Fig. 3 can be designed so that when a parallel light beam is incident on it, it can emit the parallel light beam. In other words, when a parallel light beam is incident on the first optical system 40 shown in Fig. 3, it can function as an afocal optical system.

[0045] 3, the angular magnification of the first optical system 40 is greater than 1. As a result, the light emitted from the first optical system 40 diverges as a whole. As a result, even if the illuminated surface 3 is located at a relatively short distance from the projection display device 10, the illuminated surface 3 can be illuminated over a wide range.

[0046] Furthermore, when the distance between the projection display device 10 and the illuminated area 4 is predetermined, the blurred area 90 can be further suppressed by designing the diffraction characteristics of the diffractive optical element 30 (individual element diffractive optical elements 31, 32).

[0047] <Second embodiment> Next, a second embodiment of the present disclosure will be described with reference to Fig. 4. A projection display device 10A shown in Fig. 4 differs from the projection display device 10 shown in Fig. 3 in that it includes a second optical system 50. The other configurations are substantially the same as those of the projection display device 10 shown in Fig. 3. In the second embodiment shown in Fig. 4, parts that are the same as those of the projection display device 10 shown in Fig. 3 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0048] The second optical system 50 is disposed between the laser light source 20 and the diffractive optical element 30 in the optical path of the 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 beam. In the illustrated example, the second optical system 50 is made of a collimating lens, and collimates the laser light emitted from the laser light source 20 to approach a parallel beam. As a result, the parallelized light is incident on the diffractive optical element 30, so that the diffractive optical element 30 can diffract the light in a desired direction with high precision.

[0049] The second optical system 50 is disposed at a position sufficiently distant from the laser light source 20. Therefore, the 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 is incident on a wide area of ​​the diffractive optical element 30, and the illuminated surface 3 can be widely illuminated.

[0050] <Third embodiment> Next, a third embodiment of the present disclosure will be described with reference to Fig. 5. The projection display device 10B shown in Fig. 5 differs from the projection display device 10 shown in Fig. 3 in that the laser light source 20B has a collimating lens 22. The projection display device 10B also differs in that it includes a scanning device 60. The other configurations are substantially the same as those of the projection display device 10 shown in Fig. 3. In the third embodiment shown in Fig. 5, parts that are the same as those of the projection display device 10 shown in Fig. 3 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0051] Collimating lens 22 is disposed downstream of light-emitting unit 21 in the optical path of light from light-emitting unit 21. Collimating lens 22 collimates the laser light emitted by light-emitting unit 21 to bring it closer to a parallel beam. As a result, the parallelized light is emitted from laser light source 20B and enters diffractive optical element 30. Therefore, diffractive optical element 30 can diffract the light in a desired direction with high precision.

[0052] The collimator lens 22 of the laser light source 20B is disposed near the light emitting unit 21. This makes it possible to suppress diffusion of the laser light emitted from the laser light source 20B, and to suppress blurring of the illuminated area 4 caused by the beam diameter of the light.

[0053] Next, the scanning device 60 will be described. The scanning device 60 changes the optical path of the laser light from the laser light source 20B over time, causing the light to scan the diffractive optical element 30. As a result, the incident position of the laser light on the diffractive optical element 30 moves. In other words, the diffractive optical element 30 onto 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 can rotate around one axis RA. A MEMS mirror or a galvanometer mirror may also be used as such a scanning device 60.

[0054] 5, the multiple element diffractive optical elements 31 and 32 may diffract light from the light source and emit light beams with different profiles (particularly contours). In this case, the shape of the illuminated area 4 can be changed depending on the incident position of the light on the diffractive optical element 30.

[0055] 5, the light diffracted by the plurality of element diffractive optical elements 31 and 32 may be directed toward different illuminated regions 4a and 4b. In this case, the diffraction angle range of the light diffracted by each element diffractive optical element 31 and 32 can be narrowed. In this case, the illuminated region can be moved between the illuminated region 4a and the illuminated region 4b according to the incident position of the light on the diffractive optical element 30.

[0056] Because the scanning device 60 operates at a speed exceeding the resolution of human vision, humans perceive all of the illuminated regions 4a and 4b as being continuously illuminated simultaneously. Therefore, in this case, the illumination region 4 of the projection display device 10B is the combined area of ​​all of the illuminated regions 4a and 4b. In particular, in the example shown in FIG. 5, the laser light source 20B includes a collimating lens 22, which reduces blurring of the illuminated regions 4a and 4b due to the beam diameter of the light from the laser light source 20B compared to the projection display devices 10 and 10A shown in FIGS. 1 and 2. However, the incident region of the light on the diffractive optical element 30 at each point in time is narrow. However, by operating the scanning device 60 at a speed exceeding the resolution of human vision and changing the incident position of the light on the diffractive optical element 30, it is possible to illuminate an illumination region 4 of a size comparable to that of the projection display devices 10 and 10A shown in FIGS. 1 and 2.

[0057] <Fourth embodiment> Next, a fourth embodiment of the present disclosure will be described with reference to Fig. 6. A projection display device 10C shown in Fig. 6 differs from the projection display device 10B shown in Fig. 5 in that it includes a second optical system 50C. The other configurations are substantially the same as those of the projection display device 10B shown in Fig. 5. In the fourth embodiment shown in Fig. 6, parts that are the same as those of the projection display device 10B shown in Fig. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0058] The second optical system 50C is disposed between the scanning device 60 and the diffractive optical element 30 along the optical path from the laser light source 20B 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 beam. In the example shown in FIG. 6, the second optical system 50C includes, in this order along the optical path of the light emitted from the laser light source 20B, a lens 51 and a collimating lens 52. The lens 51 shapes the light emitted from the laser light source 20B into a diverging beam. The collimating lens 52 reshapes the diverging beam generated by the lens 51 into a parallel beam.

[0059] By disposing such second optical system 50C between the scanning device 60 and the diffractive optical element 30, it is possible to increase the scanning width of the light that scans the incident surface of the diffractive optical element 30. This makes it possible to illuminate larger illuminated areas 4a and 4b compared to the projection type display device 10B shown in Fig. 5. Furthermore, since the light collimated by the second optical system 50C is incident on the diffractive optical element 30, the diffractive optical element 30 can diffract the light in a desired direction with high precision.

[0060] The scanning device 60 may control whether or not to supply laser light to the diffractive optical element 30 .

[0061] <Fifth embodiment> Next, a fifth embodiment of the present disclosure will be described with reference to Fig. 7. A projection display device 10D shown in Fig. 7 differs from the projection display device 10C shown in Fig. 6 in that a first optical system 40D forms an imaging optical system that forms an image of light diffracted by a diffractive optical element 30. The other configurations are substantially the same as those of the projection display device 10C shown in Fig. 6. In the fifth embodiment shown in Fig. 7, parts that are the same as those of the projection display device 10C shown in Fig. 6 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0062] In the example shown in FIG. 7 , the first optical system 40D forms an imaging optical system that focuses light diffracted by each of the plurality of element diffractive optical elements 31 and 32 that make up the diffractive optical element 30 onto a surface located a predetermined distance from the projection-type display device 10D. The first optical system 40D focuses the light diffracted by the diffractive optical element 30 onto a surface located downstream of the first optical system 40D in the optical path of the light from the laser light source 20. In this case, by matching the distance between the projection-type display device 10D and the irradiated surface 3 to the predetermined distance, or by bringing the distance between the projection-type display device 10D and the irradiated surface 3 closer 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 effectively suppressed. As a result, the illuminated area 4 can be illuminated extremely clearly.

[0063] Alternatively, in this case, by making the distance between the projection display device 10D and the irradiated surface 3 equal to the above-mentioned predetermined distance, or by making the distance between the projection display device 10D and the irradiated surface 3 closer to the above-mentioned predetermined distance, it is possible to suppress movement of the illuminated areas 4a, 4b in response to changes in the incident position of light on the diffractive optical element 30 by the scanning device 60.

[0064] 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.

[0065] Sixth Embodiment Next, a sixth embodiment of the present disclosure will be described with reference to Fig. 8. The projection display device 10E shown in Fig. 8 differs from the projection display device 10C shown in Fig. 6 in that a diffractive optical element 30E is designed so that blurring of an image of light emitted from the projection display device 10E is minimized on a surface that is a predetermined distance from the projection display device 10E. The other configurations are substantially the same as those of the projection display device 10C shown in Fig. 6. In the sixth embodiment shown in Fig. 8, parts that are the same as those of the projection display device 10C shown in Fig. 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0066] In the example shown in FIG. 8 , the diffraction angles of the diffractive optical elements 31e and 32e constituting the diffractive optical element 30E are determined so that the blurred area 90 in the illuminated area 4 is smallest on a surface located a predetermined distance from the projection display device 10E. In the example shown in FIG. 8 , light diffracted by the diffractive optical element 30E enters the first optical system 40, which is a non-imaging optical system, and then enters the illuminated surface 3, which is located downstream of the first optical system 40 in the optical path of the light from the laser light source 20. In this case, by matching the distance between the projection display device 10E and the illuminated surface 3 to the predetermined distance or by bringing the distance between the projection display device 10E and the illuminated surface 3 closer 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 effectively suppressed. As a result, the illuminated area 4 can be illuminated extremely clearly.

[0067] Alternatively, in this case, by making the distance between the projection display device 10E and the irradiated surface 3 equal to the above-mentioned predetermined distance, or by making the distance between the projection display device 10E and the irradiated surface 3 closer to the above-mentioned predetermined distance, it is possible to suppress movement of the illuminated areas 4a, 4b in response to changes in the incident position of light on the diffractive optical element 30E by the scanning device 60.

[0068] 8, the diffractive optical element 30E can also be designed so that the surface at the predetermined distance is inclined with respect to the optical axis of the first optical system 40. Specifically, by making the diffraction angles of light at the plurality of element diffractive optical elements 31e, 32e different from each other, it is possible to minimize blurring of the optical image caused by light diffracted by the diffractive optical element 30E on the surface inclined with respect to the optical axis of the first optical system 40. In this case, even if the illuminated surface 3 is inclined with respect to the optical axis of the first optical system 40, it is possible to obtain the effects of suppressing blurring of the illuminated region 4 and suppressing movement of the illuminated region.

[0069] In the first to sixth embodiments described above, the projection display devices 10 to 10E include a laser light source 20 or 20B, a diffractive optical element 30 or 30E that diffracts light emitted from the laser light source 20 or 20B, and a first optical system 40 or 40D located on the optical path of the light diffracted by the diffractive optical element 30 or 30E. The first optical system 40 or 40D includes a first lens group 41 with positive power onto which the light diffracted by the diffractive optical element 30 or 30E is incident, and a second lens group 42 with negative power onto which the light emitted from the first lens group 41 is incident. The angular magnification of the first optical system 40 is greater than 1. Such projection display devices 10 to 10E can suppress blurring of the illuminated area 4 due to the beam diameter of the laser light emitted from the laser light source 20, thereby enabling the illuminated area 4 to be clearly illuminated. Furthermore, the projection display devices 10 to 10E can illuminate a relatively wide area of ​​the illuminated surface 3 that is relatively close to the projection display devices 10 to 10E.

[0070] Furthermore, in the first to sixth embodiments described above, the diffraction angle of light at the diffractive optical elements 30 and 30E is 0±15° or less, which makes it possible to suppress an increase in the intensity of zero-order light and higher-order diffracted light, and to clearly illuminate the illumination area 4.

[0071] In the fifth embodiment described above, the first optical system 40D forms an imaging optical system, which can effectively suppress blurring of the illuminated area 4 caused by the beam diameter of the laser light emitted from the laser light source 20B, and can illuminate the illuminated area 4 very clearly.

[0072] Furthermore, in the first to fourth and sixth embodiments described above, the first lens group 41 and the second lens group 42 are arranged so that the optical axes of the first lens group 41 and the second lens group 42 are aligned 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. This prevents the blurred area of ​​the illuminated area 4 from expanding as the illuminated surface 3 becomes farther away from the projection display devices 10 to 10C and 10E, particularly in the first to fourth embodiments.

[0073] Furthermore, in the third to sixth embodiments described above, the projection display devices 10B to 10E further include a scanning device 60 that changes the traveling direction of the light emitted from the laser light source 20B to cause the light from the laser light source 20B to scan the diffractive optical element 30; 30E. This adjusts the optical path of the laser light emitted from the laser light source 20B, thereby controlling the distribution of the laser light to the multiple element diffractive optical elements 31, 32; 31e, 32e that make up the diffractive optical element 30; 30E. The scanning device 60 can also control whether or not to supply laser light to the diffractive optical element 30; 30E.

[0074] Furthermore, in the third to sixth embodiments described above, the laser light source 20B includes a light-emitting unit 21 that oscillates laser light and a collimating lens 22 that collimates the laser light from the light-emitting unit 21. This makes it possible to suppress blurring of the illuminated areas 4a and 4b caused by the beam diameter of the light from the laser light source 20B. Furthermore, 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 precision.

[0075] Furthermore, 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. This narrows the diffraction angle range of light diffracted by each element diffractive optical element 31, 32; 31e, 32e. As a result, it is possible to suppress an increase in the intensity of zero-order light and higher-order diffracted light, and it is possible to clearly illuminate the illuminated area 4.

[0076] Furthermore, in the first to sixth embodiments described above, the plurality of element diffractive optical elements 31, 32; 31e, 32e include at least two element diffractive optical elements 31, 32; 31e, 32e that have different diffraction angles of light from the laser light source 20B. This makes it possible to clearly illuminate the illuminated area 4 on the illuminated surface 3 that is tilted with respect to the optical axis of the first optical system 40.

[0077] Furthermore, in the first to sixth embodiments described above, the plurality of element diffractive optical elements 31, 32; 31e, 32e include at least two element diffractive optical elements 31, 32; 31e, 32e that have different radiation intensity distributions of light diffracted by the element diffractive optical elements. This makes it possible to adjust the irradiance at each position in the illuminated area 4 with higher precision, and to illuminate the illuminated area 4 with uniform brightness, for example.

[0078] Furthermore, in the second embodiment described above, the projection display device 10A further includes a second optical system 50 that shapes the light from the laser light source 20 into a parallel beam. As a result, the parallelized light is incident on the diffractive optical element 30, which can diffract the light in a desired direction with high precision.

[0079] Furthermore, 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. This allows a wide area of ​​the diffractive optical element 30; 30E to be illuminated, thereby illuminating a wide area of ​​the illuminated surface 3. Furthermore, because the parallelized light is incident on the diffractive optical element 30, the diffractive optical element 30 can diffract the light in a desired direction with high precision.

[0080] Furthermore, in the first to sixth embodiments described above, the working apparatus 1 with a projection display device comprises a working apparatus 2 that performs work while moving a part or all of it, and the above-mentioned projection display devices 10 to 10E that are attached to the working apparatus 2. Such a working apparatus 1 with a projection display device can clearly illuminate a fairly wide area of ​​the irradiated surface 3 and display desired information around the working apparatus 2.

[0081] Although several modifications of the above-described embodiment have been described, it is of course possible to combine a plurality of modifications as appropriate. [Explanation of symbols]

[0082] 1. Work device with projection display device 2. Work equipment 3 Irradiated surface 4 Illuminated area 10~10E Projection type display device 20,20B laser light source 21 Light-emitting part 22 Collimating lens 30,30E Diffractive Optical Elements 31, 32, 31e, 32e Diffractive optical elements 40,40D 1st optical system 50,50C 2nd optical system 60 Scanning Device

Claims

1. A laser light source; a diffractive optical element that diffracts the light emitted from the laser light source; a first optical system provided on an optical path of light diffracted by the diffractive optical element; Equipped with The first optical system is a first lens group having a positive power onto which light diffracted by the diffractive optical element is incident; a second lens group having negative power onto which light emitted from the first lens group is incident; Including, the first lens group and the second lens group are arranged so that the optical axes of the first lens group and the second lens group are aligned on the same straight line, and so that the rear focal point of the first lens group coincides with the front focal point of the second lens group; A projection display device, wherein the angular magnification of the first optical system is greater than 1.

2. 2. The projection display device according to claim 1, wherein the diffraction angle of the light at the diffractive optical element is 0.+-.15 degrees or less.

3. 3. The projection display device according to claim 1, wherein the first optical system forms an imaging optical system.

4. 4. The projection display device according to claim 1, further comprising a scanning device that changes the direction of travel of the light emitted from the laser light source to cause the light from the laser light source to scan the diffractive optical element.

5. 5. The projection display device according to claim 1, wherein the laser light source includes a light emitting unit that oscillates a laser beam, and a collimating lens that collimates the laser beam from the light emitting unit.

6. The projection display device according to claim 1 , wherein the diffractive optical element includes a plurality of element diffractive optical elements.

7. 7. The projection display device according to claim 6, wherein the plurality of element diffractive optical elements include at least two element diffractive optical elements that have different diffraction angles of the light from the laser light source.

8. 7. The projection display device according to claim 6, wherein the plurality of element diffractive optical elements include at least two element diffractive optical elements that have mutually different radiation intensity distributions of light diffracted by the element diffractive optical elements.

9. 9. The projection display device according to claim 1, further comprising a second optical system that shapes the light from the laser light source into a parallel beam.

10. 9. The projection display device according to claim 1, further comprising a second optical system that widens the light from the laser light source and shapes it into a parallel beam.

11. A work device that performs work while moving a part or the whole of the work device; a projection-type display device according to any one of claims 1 to 10, which is attached to the working device; A work device with a projection type display device.

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