CN113544569B - Optical element and image display device - Google Patents
Optical element and image display device Download PDFInfo
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- CN113544569B CN113544569B CN202080019319.2A CN202080019319A CN113544569B CN 113544569 B CN113544569 B CN 113544569B CN 202080019319 A CN202080019319 A CN 202080019319A CN 113544569 B CN113544569 B CN 113544569B
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- 230000003287 optical effect Effects 0.000 title claims abstract description 64
- 239000000463 material Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 4
- 238000000609 electron-beam lithography Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R11/00—Arrangements for holding or mounting articles, not otherwise provided for
- B60R11/02—Arrangements for holding or mounting articles, not otherwise provided for for radio sets, television sets, telephones, or the like; Arrangement of controls thereof
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
The invention provides an optical element and an image display device, which realize miniaturization and light weight, and can project images in multiple directions. The optical element includes: a light guide unit having a light incident surface, a plurality of side surfaces perpendicular to the light incident surface, and a back surface opposite to the light incident surface; and a plurality of diffraction grating portions formed on at least two or more surfaces selected from the side surfaces and the back surfaces.
Description
Technical Field
The present invention relates to an optical element and an image display device, and more particularly, to an optical element and an image display device using a diffraction grating.
Background
Conventionally, as a device for displaying various information in a vehicle, a dashboard for lighting and displaying icons has been used. In addition, with an increase in the amount of information displayed, it has been proposed to embed an image display device in a dashboard or to construct the entire dashboard from the image display device.
However, since the instrument panel is located below the front windshield of the vehicle, the driver needs to move the line of sight downward during the operation of the vehicle in order to view information displayed on the instrument panel, which is not preferable from the viewpoint of safety. Accordingly, a Head-Up Display (hereinafter, referred to as "Head Up Display") configured to project an image onto a front windshield and read information when a driver visually recognizes the front of a vehicle has been proposed (for example, see patent literature 1).
Fig. 6 is a schematic diagram showing the structure of an optical element used in the HUD of the related art. An optical element including a waveguide portion 1, a diffraction grating portion 2, and reflection films 3a and 3b is housed in the HUD. The waveguide section 1 has an inclined end surface 1a, a rear surface 1b, and a front surface 1c, and a diffraction grating section 2 is provided therein. Reflective films 3a and 3b are formed on the back surface 1b and the front surface 1 c. The diffraction grating section 2 is made of a material having a refractive index different from that of the waveguide section 1, and is a blazed grating having irregularities formed at predetermined intervals.
As shown in fig. 6, incident light L irradiated from a light source unit (not shown) in After entering the waveguide section 1, the light is reflected by the inclined end surface 1 a. Incident light L reflected by inclined end face 1a in Advances in the waveguide section 1, and repeatedly reflected by the reflective films 3a and 3b on the back surface 1b and the front surface 1c to reach the diffraction grating section 2. The light reaching the diffraction grating portion 2 is taken as outgoing light L out The irradiation is performed in a direction determined by the diffraction conditions of the diffraction grating section 2. Here, the diffraction conditions of the diffraction grating portion 2 are determined by the wavelength of light, the pitch of the diffraction grating portion 2, the refractive index difference between the waveguide portion 1 and the diffraction grating portion 2, the angle at which the light reaches the diffraction grating portion 2, and the like.
Patent document 1: japanese patent application laid-open No. 2018-118669
However, in the conventional HUD for vehicle use, an optical device for projecting an image over a wide area of the front windshield is required, and it is difficult to reduce the size and weight of the optical device. In addition, in the HUD using the conventional diffraction grating, the projection destination of the image is limited to one direction. Therefore, in the image display device using the conventional diffraction grating, various situations of the driver during the vehicle operation cannot be dealt with, for example, information cannot be visually recognized when the vehicle returns backward during the vehicle is moving backward.
Disclosure of Invention
The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide an optical element and an image display device which can be reduced in size and weight and can project images in a plurality of directions.
In order to solve the above problems, an optical element of the present invention includes: a light guide unit having a light incident surface, a first side surface and a second side surface perpendicular to the light incident surface and facing each other, and a back surface facing the light incident surface; and a plurality of diffraction grating portions formed on a surface of two or more surfaces selected from the first side surface, the second side surface, and the back surface, wherein at an interface between the light guide portion and the diffraction grating portions, a part of incident light is incident into the diffraction grating portions, another part is reflected as reflected light into the light guide portion, a first incident light is incident on the light incident surface, the first incident light reaches the first side surface, a part or all of the first incident light is reflected to become first reflected light, the first reflected light reaches the back surface, a part or all of the first reflected light is reflected to become second reflected light, and the second reflected light reaches the second side surface.
In the optical element of the present invention, since the light incident on the light guide portion from the light incident surface is irradiated in a predetermined direction by the plurality of diffraction grating portions, it is possible to realize downsizing and weight saving, and it is possible to project images in a plurality of directions.
In one aspect of the present invention, a reflective film is formed on a surface of the side surface and the back surface, on which the diffraction grating portion is not formed.
In one aspect of the present invention, the light incident surface includes a first light incident portion and a second light incident portion, and the first diffraction grating portion to which the first light incident from the first light incident portion first reaches is different from the second diffraction grating portion to which the second light incident from the second light incident portion first reaches.
In one aspect of the present invention, the first diffraction grating portion and the second diffraction grating portion are formed on the side surface.
In one aspect of the present invention, a prism is disposed on the light incident surface, and a gap is provided between the prism and the light incident surface.
In one embodiment of the present invention, the diffraction grating portion is made of a dielectric material having a refractive index different from that of the light guide portion.
The image display device of the present invention is characterized by comprising any one of the optical elements described above; and a light source unit that irradiates the first incident light to the light incident surface.
According to the present invention, an optical element and an image display device can be provided, which can be made compact and lightweight, and can project images in a plurality of directions.
Drawings
Fig. 1 is a schematic perspective view showing the structure of an optical element 10 in the first embodiment.
Fig. 2 is a schematic cross-sectional view showing the configuration and optical path of an image display device using the optical element 10.
Fig. 3 is a diagram schematically showing an image projection in the case where the optical element 10 is provided in the vehicle 100.
Fig. 4 is a schematic cross-sectional view showing the structure and the optical path of the optical element 10 in the second embodiment.
Fig. 5 is a schematic plan view showing the structure of the optical element 10 in the third embodiment.
Fig. 6 is a schematic diagram showing the structure of an optical element used in the HUD of the related art.
Detailed Description
(first embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or equivalent constituent elements, components, and processes shown in the drawings are denoted by the same reference numerals, and repetitive description thereof will be omitted as appropriate. Fig. 1 is a schematic perspective view showing the structure of an optical element 10 in the present embodiment. As shown in fig. 1, the optical element 10 includes a light guide portion 11, diffraction grating portions 12a, 12b, 12c, and a prism 13. Fig. 1 schematically shows the structure of the optical element 10, and the dimensions and angles in the drawing do not show the actual dimensions of the optical element 10.
The light guide 11 is a substantially plate-shaped portion made of a light-transmitting material, and includes a light incident surface 11i, side surfaces 11a, 11c, and a back surface 11b, as shown in fig. 2. The size of the light guide 11 is not limited, but may be, for example, about d=10 mm in width and t=10 mm in thickness. The material constituting the light guide 11 is not limited, but for example, siO is preferably used 2 Glass having a refractive index of about 1.5 as a main component.
The light incident surface 11i is a flat surface into which light from a light source disposed outside the optical element 10 is incident, is formed substantially perpendicular to the side surfaces 11a and 11c, and is opposed to the back surface 11b. The side surfaces 11a and 11c face each other and are flat surfaces having diffraction grating portions 12a and 12c formed on the surfaces thereof, and are formed substantially perpendicular to the light incident surface 11i and the back surface 11b. The back surface 11b is a flat surface having the diffraction grating portion 12b formed on the surface thereof, and faces the light incident surface 11 i.
The diffraction grating portions 12a, 12b, 12c are substantially plate-shaped portions formed on the surfaces of the side surfaces 11a, the back surface 11b, and the side surfaces 11c, respectively, and are made of a material having a refractive index different from that of the light guide portion 11. A plurality of convex portions and concave portions are formed periodically on the surfaces of the diffraction grating portions 12a, 12b, 12c to constitute a diffraction grating. The convex portions and concave portions of the diffraction grating portions 12a, 12b, 12c are each formed to extend in a stripe shape in a direction parallel to the light incident surface 11 i.
In fig. 1, the convex portions and concave portions of the diffraction grating portions 12a, 12b, 12c are shown as being parallel to the light incident surface 11i, but are designed so as to satisfy incident light L described later 1 Is not necessarily parallel to the light incident surface 11 i. For example, the incident light L incident obliquely can be 1 Extending in a stripe shape in the vertical direction. The diffraction grating portions 12a, 12b, and 12c may be made of the same material or may be made of different materials. If the materials of the diffraction grating portions 12a, 12b, 12c are made different, the refractive index difference at the interfaces of the diffraction grating portions 12a, 12b, 12c and the light guide portion 11 is made different, and the reflectance at the interfaces and the angle of incidence into the diffraction grating portions 12a, 12b, 12c can be changed, thereby further improving the degree of freedom of optical design.
The material constituting the diffraction grating portions 12a, 12b, 12c is not limited, but a material having a large refractive index difference from the light guide portion 11 is preferably used, and for example, tiO is preferably used 2 A dielectric material having a refractive index of about 2.5 as a main component. The diffraction grating portions 12a, 12b, 12c are not particularly limited in size, but preferably have a thickness capable of transmitting light in the in-plane direction as well. The diffraction grating portions 12a, 12b, 12c can be formed by a known method, and for example, nanoimprint technology, EBL (Electron Beam Lithography; electron beam lithography) technology, or the like can be used.
The prism 13 is an optical member having a triangular cross section and disposed in the vicinity of the light incident surface 11 i. A gap is provided between the light incident surface 11i and the prism 13, and an air layer is provided between the light incident surface 11i and the prism 13. The material constituting the prism 13 is not limited, but in order to allow light from the light source to enter the light guide 11 efficiently, it is preferable to set the refractive indices of the prism 13 and the light guide 11 to be the same, and it is preferable to use the same material as that of the light guide 11.
Preferably, the width of the gap provided between the light incident surface 11i and the prism 13 is the extent of the wavelength of light. In the example shown in fig. 1, an air layer is present in the gap, but in order to improve the optical coupling efficiency between the prism 13 and the light guide portion 11, a transparent contact liquid having a refractive index close to that of the light guide portion 11 may be filled in the gap. Although fig. 1 shows an example in which the prisms 13 are arranged with a gap therebetween, the prisms may be brought into contact with each other without providing a gap therebetween. In addition, when the reduction in optical coupling efficiency due to the influence of optical scattering is within the allowable range, light may be directly incident on the light guide 11 from the light incident surface 11i without using the prism 13.
Next, the optical path in the optical element 10 will be described with reference to fig. 2. Fig. 2 is a schematic cross-sectional view showing the configuration and optical path of an image display device using the optical element 10. As shown in fig. 2, the image display device of the present embodiment includes an optical element 10, a collimator lens 14, and a light source 15. The optical element 10 is irradiated with laser light from the light source 15, and the collimated light is incident on the prism 13 through the collimator lens 14. The collimated light enters one surface of the prism 13, is transmitted through the inside of the prism 13, and enters the gap from the surface on the gap side. Here, the area of the light incidence surface 11i into which the collimated light is incident corresponds to the light incidence portion in the present invention.
The collimated light passing through the prism 13 is incident obliquely to the light incident surface 11i of the light guide 11 through the gap. Here, by setting the width of the gap to be the same as the wavelength, light reflection at the interface between the prism 13 and the gap and at the interface between the gap and the light guide 11 can be reduced, and collimated light can be efficiently received into the light guide 11.
Incident from the light incident surface 11iAs incident light L traveling inside the light guide portion 11 1 The diffraction grating portion 12a on the surface of the side surface 11a is incident at an incident angle Φ. At the interface of the light guide portion 11 and the diffraction grating portion 12a, incident light L 1 Part of the light is incident into the diffraction grating portion 12a, and part of the light is reflected as reflected light into the light guide portion 11. Incident light L 1 The traveling angle of the light traveling in the diffraction grating portion 12a is changed according to the refractive indices of the light guide portion 11 and the diffraction grating portion 12a, and the light is output light L 2 To an emission angle theta satisfying diffraction conditions determined by the convex and concave portions d1 And (5) direction ejection. Further, by appropriately selecting the refractive index and the incident angle Φ, the condition of suppressed total reflection at the interface with air can be satisfied, and the light received into the diffraction grating portion 12a is repeatedly reflected in the diffraction grating portion 12a and propagates in the diffraction grating portion 12a.
Incident light L 1 The light reflected at the interface between the light guide portion 11 and the diffraction grating portion 12a travels in the light guide portion 11 to reach the back surface 11b, and enters the diffraction grating portion 12b on the surface of the back surface 11b at an incident angle Φ, and one portion enters the diffraction grating portion 12b and the other portion is reflected again in the light guide portion 11. The light reflected again travels in the light guide 11 to reach the side surface 11c, and enters the diffraction grating 12c on the surface of the side surface 11c at the incident angle Φ, and a part of the light enters the diffraction grating 12 c. The light entering the diffraction grating portions 12b, 12c is used as outgoing light L 3 、L 4 An emission angle θ satisfying diffraction conditions defined by the convex portions and the concave portions, like the diffraction grating portion 12a d2 、θ d3 And (5) direction ejection. Here, the outgoing light L emitted from the diffraction grating portions 12a, 12b, 12c to the outside 2 、L 3 、L 4 The emission angle of (a) is determined by the pitch of the respective convex and concave portions. Accordingly, by appropriately setting the diffraction grating portions 12a, 12b, 12c, the emitted light L can be set independently 2 、L 3 、L 4 Is arranged in the direction of emergence.
As described above, in the optical element 10 of the present embodiment, the light incident into the light guide portion 11 from the light incident surface 11i is partially reflected at the interfaces of the diffraction grating portions 12a, 12b, 12c and the light guide portion 11, and reaches the light guide portion 11The side face 11a, the back face 11b and the side face 11c are directed from the diffraction grating portions 12a, 12b, 12c to three directions as outgoing light L 2 、L 3 、L 4 And irradiating to the outside. By employing the optical element 10, it is possible to achieve downsizing and weight reduction, and to project images in a plurality of directions.
Fig. 3 is a diagram schematically showing an image projection in the case where the optical element 10 is provided in the vehicle 100. As shown in fig. 3, the optical element 10 is disposed in the roof of the vehicle 100, and light is emitted from a separately provided light source toward the optical element 10. As illustrated in fig. 2, the outgoing light L is irradiated from the optical element 10 in three directions (front, center lower, rear) toward the vehicle 100 2 、L 3 、L 4 . Forward directed light L 2 Projected to front windshield 101, and emitted light L directed rearward 4 Projected onto the rear window 102. Light L emitted toward the center downward 3 Projected onto a screen disposed in the vehicle. Here, as the screen, a non-transmissive white screen or transmissive glass may be separately provided, or a vehicle interior may be used as the screen.
As described above, in the optical element 10 and the image display device according to the present embodiment, compared with the case where a mirror or an optical lens is used, it is possible to realize downsizing and weight saving, and to simultaneously project images in a plurality of directions.
(second embodiment)
Next, a second embodiment of the present invention will be described with reference to fig. 4. The description is omitted for the contents overlapping with the first embodiment. Fig. 4 is a schematic cross-sectional view showing the structure and the optical path of the optical element 10 in the present embodiment. In the present embodiment, the reflection film 16 is formed on the surface of the back surface 11b, which is different from the first embodiment.
The reflective film 16 is a film having high reflectance and formed so as to cover the back surface 11b. The material constituting the reflective film 16 is not limited, but is preferably formed by vapor deposition of a high-reflectivity metal such as silver. Since the outgoing light is not irradiated from the surface on which the reflection film 16 is formed, the projection direction of the image can be defined. In addition, the side face 11a and the girder can be madeThe light that has reached the back surface 11b by being reflected at the interface of the diffraction grating portion 12a is efficiently reflected on the side surface 11c, and the outgoing light L that is emitted from the diffraction grating portion 12c to the outside can be improved 4 Is a strength of (a) is a strength of (b).
Fig. 4 shows an example in which the reflection film 16 is formed only on the back surface 11b, but it is preferable that the reflection film 16 is formed on all surfaces other than the light incidence surface 11i of the light guide portion 11, in which the diffraction grating portions 12a to 12c are not formed.
(third embodiment)
Next, a third embodiment of the present invention will be described with reference to fig. 5. The description is omitted for the contents overlapping with the first embodiment. Fig. 5 is a schematic plan view showing the structure of the optical element 10 in the present embodiment. The present embodiment is different from the first embodiment in that light is incident on the light guide portion 11 in two systems and a diffraction grating portion is formed on all sides.
As shown in fig. 5, in the optical element 10 of the present embodiment, diffraction grating portions 12d and 12e are also formed on the surfaces of the side surfaces orthogonal to the side surfaces 11a and 11 c. In addition, two prisms 13a, 13b are arranged in the vicinity of the light incident surface 11 i. The prisms 13a and 13b are optical members each having a triangular cross section, and are disposed so that the directions of the ridge lines are orthogonal to each other.
In the image display device of the present embodiment, two light sources 15 are provided, and light is irradiated to the prisms 13a and 13b of the optical element 10. Here, the regions of the light incidence surface 11i into which the collimated light is incident via the prisms 13a and 13b correspond to the first light incidence portion and the second light incidence portion in the present invention, respectively. As described with reference to fig. 2, light entering the light guide portion 11 through the prism 13a is emitted from the diffraction grating portions 12a, 12b, 12c as light L 2 、L 3 、L 4 Irradiation was performed in three directions. Similarly, the light entering the light guide portion 11 through the prism 13b reaches the side surface on which the diffraction grating portion 12d is formed, and part of the light enters the diffraction grating portion 12d and the other part is reflected as reflected light in the light guide portion 11. The light reflected by the side surface on which the diffraction grating portion 12d is formed is reflected again by the back surface 11b, reaches the side surface on which the diffraction grating portion 12e is formed, and partially enters the diffraction grating portion 12e. Incident diffraction gratingThe light in the portions 12d and 12e is emitted as the emitted light in a direction satisfying the diffraction conditions determined by the convex portions and the concave portions as in the first embodiment.
In the optical element 10 of the present embodiment, the diffraction grating portion 12a where light incident on the light guide portion 11 via the prism 13a reaches first is different from the diffraction grating portion 12d where light incident on the light guide portion 11 via the prism 13b reaches first. The side surface 11a on which the diffraction grating portion 12a is formed is orthogonal to the side surface on which the diffraction grating portion 12d is formed. Thus, the light incident from the prism 13a and the light incident from the prism 13b are irradiated from the diffraction grating portions 12a, 12b, 12c and the diffraction grating portions 12d, 12e to the outside through different paths in the light guide portion 11.
In the image display device using the optical element 10 according to the present embodiment, images can be projected in five directions, that is, the side surfaces 11a and 11c perpendicular to the light incident surface 11i, the side surface on which the diffraction grating portion 12d is formed, the side surface on which the diffraction grating portion 12e is formed, and the back surface 11b. In the case of application to the vehicle 100, the emitted light L is directed to the front, center lower, and rear sides as shown in fig. 3 2 、L 3 、L 4 In addition, the emitted light directed to the side can be irradiated to project an image on left and right side glass panes.
As described above, in the optical element 10 and the image display device of the present embodiment, it is possible to realize downsizing and weight saving, and it is possible to project images in five directions at the most, that is, in a plurality of directions at the same time.
(fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The description is omitted for the contents overlapping with the first embodiment. In the first to third embodiments described above, the rectangular parallelepiped light guide portion is shown as the light guide portion 11, but the shape of the light guide portion 11 is not limited. For example, the back surface 11b may be inclined at a predetermined angle with respect to the light incident surface 11i, not parallel to the light incident surface 11 i. The side surfaces 11a and 11c, the side surface on which the diffraction grating portion 12d is formed, and the side surface on which the diffraction grating portion 12e is formed may not be perpendicular to the light incident surface 11 i.
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention.
The present international application claims priority from japanese patent application publication No. 2019-072494, having a filing date of 2019, 4, 5, and the entire contents of the japanese patent application publication No. 2019-072494 are incorporated into the present international application by reference.
The foregoing description of specific embodiments of the present invention has been presented for the purpose of illustration. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. It is apparent to those skilled in the art that various modifications and variations can be made with reference to the above description.
Description of the reference numerals
L 1 … incident light
L 2 ～L 4 … emitted light
10 … optical element
100 … vehicle
101 … front windshield
102 … rear window glass
11 … light guide
11i … light incident surface
11a, 11c … side surfaces
11b … back side
12a to 12e … diffraction grating portions
13. 13a, 13b … prisms
14 … collimating lens
15 … light source
16 … reflective film.
Claims (7)
1. An optical element, comprising:
a light guide unit having a light incident surface, a first side surface and a second side surface perpendicular to the light incident surface and facing each other, and a back surface facing the light incident surface; and
a plurality of diffraction grating portions formed on the surfaces of two or more surfaces selected from the first side surface, the second side surface and the back surface,
at the interface between the light guide portion and the diffraction grating portion, a part of the incident light is incident into the diffraction grating portion, and the other part is reflected as reflected light into the light guide portion,
the first incident light is incident on the light incident surface,
the first incident light reaches the first side surface, and a part or all of the first incident light is reflected to become first reflected light,
the first reflected light reaches the back surface, and a part or all of the first reflected light is reflected to become second reflected light,
the second reflected light reaches the second side.
2. The optical element according to claim 1, wherein a reflective film is formed on a surface of the first side surface, the second side surface, and the back surface on which the diffraction grating portion is not formed.
3. An optical element according to claim 1 or 2, characterized in that,
and a third side surface and a fourth side surface perpendicular to the light incident surface and opposite to each other,
the third side and the fourth side are orthogonal to the first side and the second side,
the second incident light is incident on the light incident surface,
the second incident light reaches the third side surface, a part of the second incident light is reflected to become third reflected light,
the third reflected light reaches the back surface, and a part of the third reflected light is reflected to become fourth reflected light,
the fourth reflected light reaches the fourth side.
4. The optical element according to claim 3, wherein the diffraction grating portion is formed on at least one of the third side surface and the fourth side surface.
5. An optical element according to claim 1 or 2, characterized in that,
a prism is arranged on the light incident surface,
a gap is provided between the prism and the light incident surface.
6. The optical element according to claim 1 or 2, wherein the diffraction grating portion is constituted by a dielectric having a refractive index different from that of the light guide portion.
7. An image display device, comprising:
an optical element according to any one of claims 1 to 6; and
and a light source unit that irradiates the first incident light onto the light incident surface.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019072494A JP7373292B2 (en) | 2019-04-05 | 2019-04-05 | Optical elements and image display devices |
| JP2019-072494 | 2019-04-05 | ||
| PCT/JP2020/013655 WO2020203642A1 (en) | 2019-04-05 | 2020-03-26 | Optical element and image display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113544569A CN113544569A (en) | 2021-10-22 |
| CN113544569B true CN113544569B (en) | 2024-02-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080019319.2A Active CN113544569B (en) | 2019-04-05 | 2020-03-26 | Optical element and image display device |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP7373292B2 (en) |
| CN (1) | CN113544569B (en) |
| WO (1) | WO2020203642A1 (en) |
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| JPH11287993A (en) * | 1998-04-01 | 1999-10-19 | Shimada Precision Kk | Light guide plate for spot light source |
| JP2006228596A (en) * | 2005-02-18 | 2006-08-31 | Toppan Printing Co Ltd | Lighting system and liquid crystal display |
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| JPH0720321A (en) * | 1993-06-30 | 1995-01-24 | Nissan Motor Co Ltd | Display device |
| JP2010093078A (en) | 2008-10-08 | 2010-04-22 | Hamamatsu Photonics Kk | Optical element, laser beam oscillation device, and laser beam amplifying device |
| US8534896B2 (en) * | 2009-07-10 | 2013-09-17 | Koninklijke Philips N.V. | Free form lighting module |
| US8944662B2 (en) | 2012-08-13 | 2015-02-03 | 3M Innovative Properties Company | Diffractive luminaires |
| US9857523B2 (en) | 2014-11-24 | 2018-01-02 | Electronics And Telecommunications Research Institute | Apparatus for controlling light beam path |
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2019
- 2019-04-05 JP JP2019072494A patent/JP7373292B2/en active Active
-
2020
- 2020-03-26 WO PCT/JP2020/013655 patent/WO2020203642A1/en active Application Filing
- 2020-03-26 CN CN202080019319.2A patent/CN113544569B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1195120A (en) * | 1997-03-28 | 1998-10-07 | 夏普株式会社 | Front illumination device and reflection-type liquid crystal display device incorporating same |
| JPH11287993A (en) * | 1998-04-01 | 1999-10-19 | Shimada Precision Kk | Light guide plate for spot light source |
| JP2006228596A (en) * | 2005-02-18 | 2006-08-31 | Toppan Printing Co Ltd | Lighting system and liquid crystal display |
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| Publication number | Publication date |
|---|---|
| WO2020203642A1 (en) | 2020-10-08 |
| JP2020170125A (en) | 2020-10-15 |
| CN113544569A (en) | 2021-10-22 |
| JP7373292B2 (en) | 2023-11-02 |
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