JP2019191313A - Head-up display device - Google Patents

Abstract

Provided is a HUD device capable of displaying a virtual image that is easy for a viewer to focus on and does not easily generate a feeling of fatigue. An HUD device displays a virtual image of an image so that the image can be visually recognized by reflecting display light of the image on an image forming unit. The HUD device expands the luminous flux of the display light and guides the display light to the image forming unit side by using the waveguide 30, the light source unit 11 that functions as a light source of the display light, and the light provided from the light source unit 11. An incident optical system IOS for causing the display light to enter the wave path 30. The incident optical system IOS has a first focal length of the incident optical system IOS defined on the first meridional section MS1 and a second focal length of the incident optical system IOS defined on the second meridional section MS2. And are different from each other. [Selection diagram] FIG.

Description

  The disclosure according to this specification relates to a head-up display device (hereinafter abbreviated as a HUD device).

  Conventionally, HUD devices are known. The HUD device disclosed in Patent Document 1 has a waveguide that expands the luminous flux of image display light. Further, the HUD device disclosed in Patent Literature 2 displays a virtual image so that the image can be visually recognized by reflecting display light of the image on the imaging unit.

Special table 2017-528739 gazette JP 2017-181645 A

  Now, in the configuration in which the display light emitted from the waveguide like the HUD device of Patent Document 1 is reflected on the imaging unit as shown in Patent Document 2 to display a virtual image, the virtual image has the shape and arrangement of the imaging unit. to be influenced. As a result, it becomes a virtual image display that looks like astigmatism for a viewer, and it is difficult to focus the virtual image, so there is a concern about the generation of fatigue associated with visual recognition of the virtual image.

  One disclosed object is to provide a HUD device capable of displaying a virtual image that is easy to focus for a viewer and hardly causes fatigue.

The aspect disclosed here is a head-up display device that displays a virtual image so that an image can be visually recognized by reflecting display light of the image to the imaging unit (3a).
A waveguide (30) that expands the luminous flux of the display light and guides the display light to the imaging unit side;
A light source unit (11) that functions as a light source of display light;
An incident optical system (IOS) that causes display light to enter the waveguide by the light provided from the light source unit;
In the incident optical system, a first meridional section (MS1) and a second meridional section (MS2) orthogonal to each other are defined.
The incident optical system has a difference between a first focal length of the incident optical system defined on the first meridional section and a second focal length of the incident optical system defined on the second meridional section. It is

  According to such an aspect, the first focal length and the second focal length defined on the meridional sections orthogonal to each other of the incident optical system are different from each other. Due to such a difference in focal length, an astigmatism that corrects the influence of the shape of the imaging unit on the luminous flux of the display light incident on the waveguide by the incident optical system provided with light from the light source unit. It can be given in advance. After providing the astigmatic difference, the light beam of the display light is expanded by the waveguide, and the display light is reflected by the imaging unit, so that a virtual image with a good imaging state can be displayed. Therefore, it is possible to provide a HUD device that can display a virtual image that is easy for the viewer to focus and hardly causes fatigue.

  In addition, the code | symbol in parenthesis shows the corresponding relationship with the part of embodiment mentioned later, Comprising: It does not intend limiting the technical scope.

It is a figure which shows the mounting state to the vehicle of the HUD apparatus of 1st Embodiment. It is a perspective view of the HUD device of a 1st embodiment. It is a top view of the HUD device of a 1st embodiment. It is a side view of the HUD device of a 1st embodiment. It is a figure which shows the projector unit and folding mirror of 1st Embodiment, Comprising: It is a figure for demonstrating an incident optical system. It is a figure for demonstrating the diffraction grating structure in the input port and expansion port of 1st Embodiment. It is a figure for demonstrating the diffraction grating structure in the output port of 1st Embodiment. It is a figure for demonstrating the function of the waveguide of 1st Embodiment. It is a side view of the HUD device of a 2nd embodiment. It is a figure which shows the projector unit and folding mirror of 3rd Embodiment. FIG. 10 is a diagram showing a hologram element of a second modification. It is a figure which shows the half mirror type | mold waveguide of the modification 4.

  Hereinafter, a plurality of embodiments will be described with reference to the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other part of the configuration. In addition, not only combinations of configurations explicitly described in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not explicitly specified unless there is a problem with the combination. .

(First embodiment)
As shown in FIG. 1, the head-up display device 100 according to the first embodiment of the present disclosure is used in a vehicle 1 and is mounted in the vehicle 1 by being housed in an instrument panel 2 of the vehicle 1. ing. The HUD device 100 emits image display light toward the imaging unit 3 a set in the windshield 3 of the vehicle 1. As a result, the HUD device 100 displays a virtual image so that the image can be visually recognized by an occupant as a viewer. That is, when the display light of the image reflected by the imaging unit 3a reaches the visual recognition area EB set in the vehicle 1, the passenger whose eye point EP is located in the visual recognition area EB transmits the display light. Perceived as a virtual image VRI. The occupant can recognize various information displayed as the virtual image VRI. Examples of various types of information displayed as virtual images include information indicating the state of the vehicle 1 such as the vehicle speed and the remaining amount of fuel, or navigation information such as visibility assistance information and road information.

  In the following description, unless otherwise specified, front, rear, front and rear directions, upper, lower, up and down directions, left, right, and left and right directions are described with reference to the vehicle 1 on the horizontal plane HP.

  The windshield 3 of the vehicle 1 is formed in a translucent plate shape by glass or synthetic resin, for example, and is disposed above the instrument panel 2. The windshield 3 is disposed so as to be more rearward from the lower side toward the upper side. The windshield 3 has an image forming portion 3a on which an image is projected, formed in an anamorphic surface curved in a smooth concave shape. Such a shape of the windshield 3 is generally set by a vehicle manufacturer based on the use or design of the vehicle 1. For example, the imaging portion 3a is formed in a concave shape so that the curvature in the left-right direction is larger than the curvature in the up-down direction by being formed so as to bend more in the left-right direction than in the up-down direction. The HUD device 100 is configured to project display light onto the image forming unit 3 a of the windshield 3.

  The visual recognition area EB is a spatial area that is visible so that the virtual image VRI displayed by the HUD device 100 satisfies a predetermined standard (for example, the entire virtual image VRI can be visually recognized with a predetermined luminance or higher), and is also referred to as an eye box. Is done. The visual recognition area EB is typically set so as to overlap with the eyelips set in the vehicle 1. The eyelips are set in an ellipsoidal shape based on an eye range that statistically represents the spatial distribution of the occupant's eye points EP.

  A specific configuration of such a HUD device 100 will be described below with reference to FIGS. As shown in FIGS. 2 to 4, the HUD device 100 includes a projector unit 10, a folding mirror 20, a waveguide 30, and the like. For example, these components are accommodated in a light-shielding housing 6 formed in a hollow shape. The HUD device 100 of the present embodiment is greatly reduced in size by realizing a configuration that does not require a conventional large concave mirror or the like.

  The projector unit 10 projects image display light (hereinafter simply referred to as display light). As shown in FIG. 5, the projector unit 10 includes a light source unit 11, an image element unit 12, a projection lens unit 13, and the like, which are accommodated in a casing 10a. An example of a specific configuration of the projector unit 10 will be described below.

  The light source unit 11 functions as a light source for display light. For the light source unit 11, for example, a plurality of laser oscillators are employed. Each laser oscillator employs, for example, a semiconductor laser and oscillates laser beams having different wavelengths in the visible region. When three laser oscillators are provided, for example, a laser oscillator that oscillates green laser light having a peak wavelength in the range of 490 to 530 nm, preferably 515 nm, and a peak wavelength in the range of 430 to 470 nm, preferably 640 nm. For example, a laser oscillator that oscillates blue laser light and a laser oscillator that oscillates red laser light having a peak wavelength in the range of 600 to 650 nm, preferably 640 nm can be employed.

  For the image element unit 12, a reflective liquid crystal element formed by providing a liquid crystal layer on a silicon substrate such as LCOS (Liquid crystal on silicon) is employed. A plurality of reflective liquid crystal elements are provided so as to correspond to light of each wavelength emitted by each laser oscillator, for example. Each reflective liquid crystal element can control the reflectance of incident light for each liquid crystal pixel configured by two-dimensionally arranging pixel electrodes. Each reflective liquid crystal element can generate an image corresponding to each wavelength by controlling the reflectance. Thereafter, the images corresponding to the respective wavelengths are combined with each other using the dichroic prism, and the display light is incident on the projection lens unit 13. Further, in the optical system using the HUD device 100, the reflective liquid crystal element and the virtual image VRI are in a conjugate relationship.

  The projection lens unit 13 condenses the display light from the image element unit 12 and projects it to the outside of the projector unit 10 (particularly, the folding mirror 20 in the present embodiment). The projection lens unit 13 includes a plurality of lenses 14, 15, and 16 so as to constitute a lens group in which the entire optical power is positive. Each lens 14, 15, 16 refracts the display light emitted from the image element unit 12 and adjusts the projection state of the display light.

  In this way, the projector unit 10 projects display light from the front to the rear of the vehicle 1 as shown in FIGS.

  The folding mirror 20 is disposed on the projector unit 10 side of the waveguide 30, that is, between the projector unit 10 and the waveguide 30 on the optical path of the display light. The folding mirror 20 is a reflecting mirror in which a reflecting surface 21 is formed on the surface of a base material made of synthetic resin or glass, for example, by metal deposition of aluminum. The reflective surface 21 is formed in a smooth flat shape, for example. Display light incident on the folding mirror 20 from the projector unit 10 is reflected toward the input port 33 of the waveguide 30.

  As shown in FIGS. 3 and 4, the waveguide 30 includes an input port 33, an expansion port 35, and an output port 37 on the plate surfaces 31 a and 31 b of the light-transmitting plate-like base material 31 made of glass or synthetic resin, for example. It is provided and is formed in a flat plate shape. The waveguide 30 is extended above the projector unit 10 and the folding mirror 20 so as to have a rectangular outline in the front-rear direction and the left-right direction. The input port 33 faces the folding mirror 20 in the vertical direction. ing. In other words, the input port 33 is provided on the plate surface 31 a facing downward in the plate-like base material 31.

  On the other hand, the expansion port 35 and the output port 37 are provided on the plate surface 31b facing upward, in other words, on the plate surface 31b opposite to the plate surface 31a. The expansion port 35 is disposed at a position displaced forward with respect to the input port 33 so as to avoid overlapping with the input port 33 in the plate thickness direction (vertical direction in the present embodiment). The output port 37 is arranged at a position shifted leftward or rightward with respect to the expansion port 35 so as to avoid overlap in the plate thickness direction with the input port 33 and the expansion port 35.

  A direction D1 connecting the input port 33 and the expansion port 35 is defined along the front-rear direction on a virtual plane along the plate surfaces 31a and 31b of the waveguide 30 as described above, and the expansion port 35 and the output port 37 are defined. A direction D2 is defined to extend along the left-right direction. The direction D1 and the direction D2 are substantially at an angle of 90 degrees.

  The plate surface 31a on the input port 33 side and the plate surface 31b on the expansion port 35 and output port 37 side of the plate-like base material 31 are arranged substantially parallel to each other, and each is planar and guides display light by reflection. It is formed in the shape of a mirror that allows light.

  The input port 33 is formed in a rectangular shape, more specifically, in a square shape so as to have a smaller surface area than the expansion port 35 and the output port 37. The input port 33 is formed thinner than the plate-like base material 31, and is joined to the plate surface 31a. The display light projected by the projector unit 10 is incident on the input port 33 via the folding mirror 20, and the input port 33 introduces the display light into the waveguide 30. The input port 33 of the present embodiment employs a diffraction grating structure 34 that is a kind of diffractive optical element (DOE).

  As shown in an enlarged view in FIG. 6, the diffraction grating structure 34 is formed by periodically arranging prism-like extending structures 34 a extending linearly in an orthogonal direction orthogonal to the direction D <b> 1 along the direction D <b> 1. It is formed in a lattice shape. In the diffraction grating structure 34, the arrangement pitch of the extending structures 34a and the height of the structure are appropriately set in consideration of each wavelength of the display light and are blazed, so that the diffraction order is the first order. It is formed so that the diffraction efficiency of the first-order diffracted light is higher than the diffraction efficiency of the diffracted light of other orders. When the display light is incident on the diffraction grating structure 34, the first-order diffracted light is diffracted toward the inside of the plate-like base material 31 and the expansion port 35 side at an angle that is totally reflected by the plate surface 31b. . The first-order diffracted light reciprocates between the plate surfaces 31 a and 31 b while being totally reflected, and sequentially reaches the expansion port 35.

  As shown in FIG. 3, the expansion port 35 extends in the direction D1 so as to move away from the input port 33, and has a trapezoidal shape that widens in the orthogonal direction perpendicular to the direction D1 as it moves away from the input port 33. Is formed. The expansion port 35 is formed thinner than the plate-like base material 31, and is joined to the plate surface 31b. The expansion port 35 of the present embodiment employs a diffraction grating structure 36 that is a kind of diffractive optical element.

  As shown in an enlarged view in FIG. 6, the diffraction grating structure 36 includes a prism-like extending structure 36a linearly extending in a direction D3 (see also FIG. 3) that obliquely intersects the direction D1, and the direction D3. Are periodically arranged in orthogonal directions to form a lattice shape. For example, in this embodiment in which the direction D1 and the direction D2 form an angle of 90 degrees, the direction D3 forms an angle of 45 degrees, which is a half angle of 90 degrees, with respect to the direction D1. Similar to the diffraction grating structure 34 of the input port 33, the diffraction grating structure 36 is formed so that the diffraction efficiency of the diffracted light of a specific order is higher than the diffraction efficiency of other orders.

  When the display light is incident on the diffraction grating structure 36 of the expansion port 35 from the input port 33, the diffracted light of a specific order is totally reflected on the plate surface 31a to the inside of the plate-like base material 31. Diffracted toward. At this time, since the direction D3 intersects the direction D1 in which the display light from the input port 33 travels, the display light is substantially output along the direction D2 inside the plate-like substrate 31. The component is substantially divided into a component toward the port 37 and a component further away from the input port 33 in the expansion port 35 along the direction D1. As a result, the display light is expanded in the direction D1 by the light flux at the expansion port 35 and is deflected in the direction D2.

  Similar to the diffraction at the input port 33, the light deflected in the direction D2 travels between the plate surfaces 31a and 31b while traveling back and forth between the plate surfaces 31a and 31b, and is output. The port 37 is reached sequentially.

  As shown in FIGS. 3 and 4, the output port 37 is formed in a rectangular shape (rectangular shape) having the direction D2 as a longitudinal direction by extending along the direction D2 so as to move away from the expansion port 35. . The shape of the output port 37 generally corresponds to the shape of the visual recognition area EB. The output port 37 is formed thinner than the plate-like base material 31 and is bonded to the plate surface 31b. The output port 37 of the present embodiment employs a diffraction grating structure 38 that is a kind of diffractive optical element.

  In the diffraction grating structure 38, as shown in an enlarged view in FIG. 7, prism-like protrusion structures 38a extending along a direction D1 orthogonal to the direction D2 are periodically arranged at intervals. Between each protrusion structure 38a, the planar planar structure 38b which makes a level | step difference with the front-end | tip of the protrusion structure 38a is formed, and the protrusion structure 38a and the planar structure 38b are alternately arrange | positioned at stripe form. . In the diffraction grating structure 38, the arrangement pitch and the height of the protrusion structure 38a are appropriately set in consideration of each wavelength of the display light. Accordingly, the respective diffraction efficiencies are set so that the 0th-order diffracted light having the 0th diffraction order and the 1st-order diffracted light having the 1st diffraction order are branched in a predetermined ratio in different directions. .

  More specifically, the diffraction grating structure 38 diffracts the 0th-order diffracted light in the direction D2 inside the plate-like base material 31 and further away from the expansion port 35 when the display light guided by the expansion port 35 is incident. . This 0th-order diffracted light is totally reflected by the plate surface 31 a and reaches a position farther from the expansion port 35 at the output port 37. On the other hand, the diffraction grating structure 38 diffracts the first-order diffracted light toward the outside of the plate-like base material 31, that is, the outside of the waveguide 30. As a result, the display light is expanded in the direction D2 by the 0th-order diffracted light at the output port 37, and the display light is directed from the respective portions of the output port 37 to the imaging unit 3a outside the waveguide 30 by the first-order diffracted light. It is injected towards.

  In this way, as shown in FIG. 8, the waveguide 30 as a light (electromagnetic wave) transmission path expands the luminous flux of the display light in the direction D1 and the direction D2, and forms an image of the display light on the optical path. Guide to the part 3a side. In other words, the waveguide 30 functions as an exit pupil enlarging element that enlarges the exit pupil of the optical system by the HUD device 100.

  The display light emitted from the waveguide 30 travels from the output port 37 toward the upper windshield 3. At this time, due to the output port 37 whose longitudinal direction is the lateral direction of the vehicle 1, the light flux of the display light is connected to the windshield 3 in a state where the lateral diameter of the vehicle 1 is larger than the longitudinal dimension of the vehicle 1. The light enters the image portion 3a. When the luminous flux of the display light is reflected by the imaging unit 3a, the traveling direction of the display light is deflected rearward, and the diameter of the vehicle 1 in the left-right direction is larger than the diameter of the vehicle 1 in the vertical direction. For example, it reaches the visual recognition area EB located above the passenger's seat. Therefore, the visual recognition area EB is formed in a rectangular shape in which the diameter of the vehicle 1 in the left-right direction is larger than the diameter of the vehicle 1 in the up-down direction.

  As shown in FIG. 5, the projection lens unit 13 of the present embodiment has a so-called triplet lens configuration in which three lenses are arranged in the order of the convex lens 14, the concave lens 15, and the convex lens 16 from the image element unit 12 side. Yes. Specifically, the incident side refracting surface 14a and the exit side refracting surface 14b of the convex lens 14 closest to the image element unit 12 have a rotationally symmetric shape having substantial symmetry with respect to rotation at an arbitrary angle around the optical axis. Is adopted. A rotationally symmetric shape having substantial symmetry with respect to rotation at an arbitrary angle around the optical axis is also present on the incident side refractive surface 15a and the exit side refractive surface 15b of the concave lens 15 sandwiched between the two convex lenses 14 and 16. It has been adopted.

  The incident side refractive surface 16a of the convex lens 16 on the most folding mirror 20 side (in other words, on the waveguide 30 side) has a rotationally symmetric shape having substantial symmetry with respect to rotation at an arbitrary angle around the optical axis. ing. On the other hand, the exit-side refracting surface 16b of the convex lens 16 has a rotationally asymmetric shape that has no symmetry with respect to rotation at an arbitrary angle around the optical axis and has symmetry that is practical only for rotation of 90 degrees. Has been. More specifically, the exit-side refractive surface 16b is a convex toroidal surface that is a kind of anamorphic surface.

  Then, the elements arranged on the optical path between the light source unit 11 and the input port 33 of the waveguide 30, specifically the image element unit 12, the projection lens unit 13, and the folding mirror 20 in the present embodiment are combined and incident. It is redefined as the optical system IOS. The incident optical system IOS has a positive optical power as a whole, and is an optical system that causes display light to enter the waveguide 30 by light provided from the light source unit 11.

  In the incident optical system IOS, a first meridional section MS1 and a second meridional section MS2 orthogonal to each other can be defined. For example, the first meridional section MS1 can be defined so as to include the direction with the largest curvature and the optical axis direction AD on the exit side refractive surface 16b of the convex lens 16, and the direction with the smallest curvature and the optical axis direction AD. The second meridional section MS2 can be defined to include The first meridional section MS1 is a section corresponding to the vertical direction in the virtual image VRI, and the second meridional section MS2 is a section corresponding to the left and right direction in the virtual image VRI.

  The first focal length of the incident optical system IOS defined on the first meridional section MS1 and the second focal length of the incident optical system IOS defined on the second meridional section MS2 are different from each other. ing. The first focal length corresponding to the direction in which the curvature of the imaging unit 3a is small is shorter than the second focal length corresponding to the direction in which the curvature of the imaging unit 3a is large. This difference in focal length is caused by the shape of the exit-side refractive surface 16b of the convex lens 16, particularly in the present embodiment.

  Due to the difference in focal length, an astigmatic light beam having an astigmatic difference enters the input port 33 of the waveguide 30 from the folding mirror 20 of the incident optical system IOS as a light beam of display light. In other words, the wavefront of the luminous flux of the display light incident on the input port 33 also has a rotationally asymmetric shape like a toroidal surface.

  The waveguide 30 is configured to leave the astigmatic difference in the luminous flux of the incident display light by the configuration of the plate surfaces 31a and 31b and the configuration of the ports 33, 35, and 37 described above. That is, the light flux of the display light is expanded in diameter inside the waveguide 30, but maintains a rotationally asymmetric shape at the wavefront when exiting from the output port 37. The residual astigmatism here is not limited to the case where the astigmatic difference of the same level as that at the time of input is maintained at the time of output. This includes cases where the image remains so as to affect the image.

  An astigmatic light beam in which an astigmatic difference remains from the waveguide 30 is emitted as a light beam of display light, so that the imaging portion 3a is formed in a concave shape so that the curvature in the left-right direction is larger than the curvature in the vertical direction. Is corrected so that the astigmatic difference is reduced or eliminated (in other words, the wavefront approaches a spherical surface).

(Function and effect)
The operational effects of the first embodiment described above will be described again below.

  According to the first embodiment, the first focal length and the second focal length defined on the meridional sections MS1 and MS2 orthogonal to each other of the incident optical system IOS are different from each other. Due to the difference in focal length, the incident optical system IOS provided with light from the light source unit 11 corrects the influence of the shape of the imaging unit 3a on the luminous flux of the display light incident on the waveguide 30. Astigmatic difference can be given in advance. After providing the astigmatism difference, the light flux of the display light is expanded by the waveguide 30 and the display light is reflected by the imaging unit 3a, so that it is possible to display a virtual image VRI with a good imaging state. Therefore, it is possible to provide the HUD device 100 that can display the virtual image VRI that is easy for the viewer to focus on and hardly causes fatigue.

  Further, according to the first embodiment, the waveguide 30 on which the display light beam is incident as an astigmatic beam having an astigmatic difference is configured to emit the display light beam with the astigmatic difference remaining. Yes. Since the light flux of the display light is reflected to the imaging unit 3a with the astigmatic difference remaining by the waveguide 30, the influence of the shape of the imaging unit 3a can be easily corrected. A virtual image VRI in good condition can be displayed.

  Further, according to the first embodiment, in the incident optical system IOS, at least one of the refractive surfaces 14a, 14b, 15a, 15b, 16a, and 16b formed by the projection lens unit 13 is an anamorphic surface. Thus, the first focal length is different from the second focal length. That is, the action of correcting various aberrations by the projection lens unit 13 and the provision of astigmatism are combined, and the imaging state of the virtual image VRI can be further improved.

  Further, according to the first embodiment, of the refracting surfaces 14a, 14b, 15a, 15b, 16a, and 16b formed by the projection lens unit 13, the exit-side refracting surface 16b that is located closest to the waveguide 30 on the optical path. Is an anamorphic surface. By using the refracting surface 16b on the waveguide 30 side as an anamorphic surface, it is possible to allow the display light to pass through the anamorphic surface in a state where the display light is wider than when incident on the projection lens unit 13. Therefore, the astigmatic difference can be given to the entire luminous flux of the display light with higher accuracy, so that the imaging state of the virtual image VRI can be further improved.

(Second Embodiment)
As shown in FIG. 9, the second embodiment is a modification of the first embodiment. The second embodiment will be described with a focus on differences from the first embodiment.

  In the second embodiment, each refracting surface of the projection lens unit 213 has a rotationally symmetric shape having substantial symmetry with respect to rotation at an arbitrary angle. On the other hand, the reflecting surface 221 of the folding mirror 220 is a concave cylindrical surface which is a kind of anamorphic surface.

  More specifically, the reflecting surface 221 is a cylindrical surface with a cylindrical generatrix along the left-right direction. As a result, the reflective surface 221 is set such that the curvature in the left-right direction is smaller than the curvature in the direction orthogonal to the left-right direction. In the present embodiment, the left-right direction on the reflection surface 221 corresponds to the left-right direction of the virtual image VRI.

  Also in the second embodiment, the first focal length of the incident optical system IOS and the second focal length of the incident optical system IOS are different from each other. This difference in focal length is caused by the shape of the folding mirror 220, particularly in this embodiment.

  According to the second embodiment described above, the first focal length and the second focal length are made different by making the reflecting surface 221 formed by the folding mirror 220 an anamorphic surface. Yes. In other words, it is possible to allow the display light to pass through the anamorphic surface immediately before entering the input port 33 where the display light is in the most spread state in the incident optical system IOS. Therefore, the astigmatic difference can be given to the entire luminous flux of the display light with higher accuracy, so that the imaging state of the virtual image VRI can be further improved.

(Third embodiment)
As shown in FIG. 10, the third embodiment is a modification of the first embodiment. The third embodiment will be described with a focus on differences from the first embodiment.

  The projector unit 10 of the third embodiment employs a MEMS scanner system. A light emitting diode element is employed for the light source unit 311 of the third embodiment. The light emitting diode element is disposed on the light source circuit board and is electrically connected to the power source through the wiring pattern on the board. The light-emitting diode element is formed by sealing a chip-like blue diode element with a yellow phosphor obtained by mixing a translucent synthetic resin with a yellow phosphor. The yellow phosphor is excited by the blue light emitted from the blue diode element according to the amount of current to emit yellow light, and pseudo white light is emitted by the combination of the blue light and the yellow light.

  The image element unit 312 of the third embodiment includes an adjustment lens unit 312a, a light guide mirror 312d, and a scanning unit 312e. The adjustment lens unit 312a includes a single lens, and condenses the light from the light source unit 311 to be converted into a parallel light beam. The state of the light beam of the display light is adjusted by the adjustment lens unit 312a and reflected by the light guide mirror 312d, and then the light beam of the display light is supplied to the scanning unit 312e.

  More specifically, at least one of the entrance-side refracting surface 312b and the exit-side refracting surface 312c of the adjustment lens unit 312a of the present embodiment is a convex toroidal surface that is a kind of anamorphic surface. Particularly in the present embodiment, the exit-side refractive surface 312c is a convex toroidal surface.

  A scanning mirror 312f is employed in the scanning unit 312e. The scanning mirror 312f is a MEMS mirror configured using a micro electro mechanical system (MEMS) and capable of temporally scanning a light beam of display light. The scanning mirror 312f forms a reflecting surface by metal deposition of aluminum or the like. The reflecting surface is rotatable around two rotation axes that are substantially orthogonal to each other along the reflecting surface.

  Such a scanning mirror 312f is electrically connected to the controller, and can turn the reflecting surface by rotating in accordance with the scanning signal.

  The luminous flux of the display light is incident on the reflecting surface of the scanning mirror 312f. When the scanning mirror 312f is controlled by the controller, the light beam of the display light is temporally started from the deflection point TL that is the incident position of the display light on the reflecting surface in conjunction with the light source unit 311. The projection direction can be deflected and scanned. By scanning such a luminous flux of the display light within a scanning angle range RG corresponding to the swing angle of the scanning mirror 312f, the scanning mirror 312f can draw and generate an image displayed as a virtual image VRI.

  The display light beam scanned on the scanning mirror 312 f by the deflection at the deflection point TL is reflected from the projector unit 10 to the folding mirror 20 and projected as display light toward the input port 33 of the waveguide 30.

  The incident optical system IOS of the third embodiment includes an adjustment lens unit 312a, a light guide mirror 312d, a scanning unit 312e, and a folding mirror 20. The first focal length of the incident optical system IOS and the second focal length of the incident optical system IOS are different from each other. This difference in focal length is caused by the shape of the adjustment lens portion 312a, particularly in this embodiment.

  According to the third embodiment described above, by setting at least one of the refracting surfaces 312b and 312c formed by the adjustment lens portion 312a as an anamorphic surface, the first focal length and the second The focal length is different. That is, since the display light passes through the anamorphic surface before the light beam of the display light is scanned by the scanning unit 312e, an astigmatic difference can be uniformly given to each pixel after drawing, and the virtual image VRI The imaging state can be made even better.

(Other embodiments)
Although a plurality of embodiments have been described above, the present disclosure is not construed as being limited to those embodiments, and can be applied to various embodiments and combinations without departing from the scope of the present disclosure. Can do.

  Specifically, as the first modification, the imaging unit 3 a may not be provided on the windshield 3. For example, a combiner that is separate from the vehicle 1 may be installed in the vehicle 1, and the imaging unit 3 a may be set in the combiner.

  As Modification 2, as shown in FIG. 11, a hologram element 939, which is a kind of diffractive optical element, is employed in at least one of the input port 33, the expansion port 35, and the output port 37 of the waveguide 30. Also good. The hologram element 939 is formed in a thin flat plate shape by sandwiching the hologram layer 939b between a pair of light-transmitting substrate layers 939a such as synthetic resin or glass. The hologram layer 939b is formed to be translucent with a composition made of a synthetic resin, for example, and has a striped periodic refractive index distribution. Display light can be diffracted by such a refractive index distribution. With this configuration, the performance of the waveguide 30 is unlikely to change due to the influence of sunlight heat.

  As a third modification, the diffracted light used for light guide by the input port 33, the expansion port 35, and the output port 37 in the waveguide 30 may be diffracted light of other orders, for example, higher order than the first order diffracted light. Diffracted light.

  As a fourth modification, as shown in FIG. 12, as a waveguide 30, a half mirror 930 a is arranged inside a plate-like base material 31, and the half mirror 930 a branches display light into transmitted light and reflected light. A half mirror type waveguide that expands the luminous flux of the display light may be employed.

  As a modified example 5, a DLP (registered trademark, Digital Light Processing) method can be adopted as the projector unit 10, and a DMD (Digital Micromirror Device) can be adopted as the image element unit 12.

  As a sixth modification related to the first embodiment, the exit-side refractive surface 16b of the convex lens 16 may be a cylindrical surface or a free-form surface.

  As a modified example 7 related to the first embodiment, an arbitrary refracting surface among the refracting surfaces 14a, 14b, 15a, 15b, 16a, and 16b formed by the projection lens unit 13 may be an anamorphic surface. The refracting surface or the entire refracting surface may be an anamorphic surface.

  As a modification 8 related to the second embodiment, the reflecting surface 221 of the folding mirror 220 may be a toroidal surface or a free-form surface.

  As a ninth modified example related to the first and second embodiments, the projection lens units 13 and 213 are not limited to a triplet lens configuration, and various lens configurations constructed by an arbitrary number of lenses can be employed.

  As a tenth modification related to the third embodiment, a projector unit 310 may employ a plurality of laser oscillators as the light source unit 311 as in the first embodiment. In this case, the adjustment lens unit 312a may be configured by arranging a plurality of lenses in parallel so as to individually correspond to each laser oscillator. Further, the light guide mirror 312d may be replaced with a plurality of dichroic mirrors so as to synthesize the light beams of the respective laser beams that have passed through the adjustment lens unit 312a from the respective laser oscillators.

  As a modified example 11, an adjustment mechanism is set such that a rotation axis extending in the left-right direction is set on the folding mirror 20, and the rotation axis is rotated so that the display position of the virtual image VRI and the position of the visual recognition area EB move up and down. May be added.

  As a twelfth modification, the HUD device 100 can be applied to various vehicles such as an aircraft, a ship, or a casing that does not move (for example, a game casing).

  100 HUD device, 3a imaging unit, 11 light source unit, 30 waveguide, IOS incident optical system, MS1 first meridional section, MS2 second meridional section

Claims (6)

A head-up display device that displays a virtual image so that the image can be visually recognized by reflecting display light of the image to the imaging unit (3a),
A waveguide (30) for expanding the luminous flux of the display light and guiding the display light to the imaging unit side;
A light source unit (11) functioning as a light source of the display light;
An incident optical system (IOS) that causes the display light to enter the waveguide by the light provided from the light source unit;
In the incident optical system, a first meridional section (MS1) and a second meridional section (MS2) orthogonal to each other are defined.
The incident optical system includes a first focal length of the incident optical system defined on the first meridional section and a second focal length of the incident optical system defined on the second meridional section. Are different from each other. The light beam of the display light is incident on the waveguide as an astigmatic light beam having an astigmatic difference,
The head-up display device according to claim 1, wherein the waveguide is configured to emit the light beam of the display light with the astigmatic difference remaining. The incident optical system is:
An image element unit (12) for generating the image;
A projection lens part (13) for condensing the display light emitted from the image element part,
By making at least one of the refractive surfaces (14a, 14b, 15a, 15b, 16a, 16b) formed by the projection lens unit an anamorphic surface, the first focal length and the first The head-up display device according to claim 1, wherein the focal lengths of the two are different.   4. The head-up display device according to claim 3, wherein among the refractive surfaces formed by the projection lens unit, the refractive surface located closest to the waveguide on the optical path is an anamorphic surface. 5. The incident optical system is:
An image element unit (12) for generating the image;
A folding mirror (220) that is disposed at a position facing the input port of the waveguide and that reflects the display light incident from the image element unit side on the optical path to the input port side by reflection;
3. The first focal length and the second focal length are differentiated by making the reflecting surface (221) formed by the folding mirror an anamorphic surface. 4. The head-up display device described in 1. The incident optical system is:
A scanning unit (312e) for drawing the image by scanning a light flux of the display light;
An adjustment lens unit (312a) that adjusts the state of the luminous flux of the display light supplied to the scanning unit by refraction,
By making at least one refracting surface (312b, 312c) formed by the adjustment lens portion an anamorphic surface, the first focal length and the second focal length are different from each other. The head-up display device according to claim 1 or 2.

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