JP6098375B2 - Head-up display device - Google Patents

Description

  The present invention relates to a head-up display device.

  The vehicle information is displayed as if the vehicle information is displayed in front of the windshield of the vehicle so that the vehicle driver can read the vehicle information (display image) such as the speed without moving the line of sight while driving. Development of a head-up display device that projects information on a windshield is in progress.

  Patent Document 1 discloses a head-up display device that uses a semiconductor laser as a light source for the head-up display device to project a display image. The head-up display device includes a semiconductor laser, a scanning system, and a screen, and scans laser light emitted from the semiconductor laser toward the screen to generate a display image.

  In a head-up display device using laser light as a light source, the visibility of a display image is reduced due to speckle. Speckle is caused by the interference of diffused laser light.

  As a head-up display device with reduced speckles, a head-up display device disclosed in Patent Document 2 is known. In this head-up display device, a double-arranged microlens array is used. The double-arranged microlens array emits laser light by the refractive action of the microlens regardless of the diffusing agent and the surface irregularities, so that the generation of speckle can be reduced.

JP-A-7-270711 Special table 2007-523369 gazette

  In the head-up display device described in Patent Document 2, when the laser beam shape, the beam intensity distribution, and the like deviate from predetermined conditions, luminance unevenness and color unevenness occur in the display image. When a simple optical system is used and the conditions such as the beam shape are satisfied, the light use efficiency is lowered. Therefore, a complex optical system is required to satisfy the conditions such as the beam shape.

  The present invention has been made in view of the above, and an object of the present invention is to provide a head-up display device that displays a display image without speckles and luminance unevenness with a simple configuration.

In order to achieve the above object, a head-up display device according to the present invention includes:
A laser light source that emits laser light;
A scanning unit that scans laser light emitted from the laser light source unit;
A first microlens array in which a plurality of microlenses are arranged, on which the scanned laser light is incident on the scanning unit,
The horizontal pitch of the first microlens array is larger than the horizontal beam diameter of the laser light incident on the first microlens array,
The vertical pitch of the first microlens array is equal to or less than the vertical beam diameter of the laser light incident on the first microlens array.
It is characterized by that.

  According to the present invention, it is possible to display a display image without speckles and luminance unevenness with a simple configuration.

It is a schematic diagram which shows the outline of the head-up display apparatus which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure of the head-up display apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the laser light source part which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the aperture which concerns on Embodiment 1 of this invention. It is a figure which shows the change of the beam cross-sectional shape of the red laser beam based on Embodiment 1 of this invention, and the intensity distribution of a beam cross section. It is a schematic diagram which shows the structure of the 1st microlens array which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the aperture array which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the arrangement | positioning of the 1st micro lens array which concerns on Embodiment 1 of this invention, an aperture array, and the optical path of a laser beam. It is a schematic diagram which shows the arrangement | positioning of the 1st micro lens array which concerns on Embodiment 1 of this invention, an aperture array, and the optical path of a laser beam. It is a block diagram which shows the structure of the control part which concerns on Embodiment 1 of this invention. It is a figure which shows the beam cross-sectional shape of the laser beam which injected into the 1st micro lens array which concerns on Embodiment 1 of this invention, and intensity distribution of a beam cross section. It is a figure which shows the interference fringe formed on Eyebox. It is a figure for demonstrating the laser beam (red) which interfered which forms the bright part of an interference fringe in the orthogonal | vertical direction based on Embodiment 1 of this invention. It is a figure which shows intensity distribution of the orthogonal | vertical direction in the beam cross section of the laser beam on Eyebox which concerns on Embodiment 1 of this invention. It is a figure which shows the change of the intensity distribution of the horizontal direction in the beam cross section of the laser beam on Eyebox in case a laser beam moves 1 pixel in a horizontal direction. It is a figure which shows the intensity distribution of the horizontal direction in the beam cross section of the laser beam on Eyebox which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of a 2nd micro lens array. It is a figure which shows arrangement | positioning of the 1st micro lens array which concerns on Embodiment 2 of this invention, and a 2nd micro lens array. It is a schematic diagram which shows the structure of the assembled 1st micro lens array and 2nd micro lens array which concern on Embodiment 2 of this invention. It is a schematic diagram which shows the structure of the assembled 1st micro lens array and 2nd micro lens array which concern on Embodiment 2 of this invention.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 shows an outline of a head-up display device 100 according to the present embodiment. Head-up display device 100 according to the present embodiment is installed in the dashboard of vehicle 200 as shown in FIG. The head-up display device 100 emits display light representing the virtual image V of the display image M from the emitting unit 101 to the windshield 201 of the vehicle 200. The display light reflected by the windshield 201 reaches the observer's eye 1. An observer visually recognizes a virtual image V of the display image M represented by the display light reflected on the windshield 201 (virtual image projected on the windshield 201) in Eyebox 3 which is a viewing zone. The observer recognizes that the display image M is far away through the windshield 201.

  FIG. 2 shows an outline of a cross section in the vertical direction of the vehicle 200 (FIG. 1) of the head-up display device 100. As shown in FIG. 2, the head-up display device 100 includes a laser light source unit 10, a scanning unit 20, a refracting unit 30, a first microlens array 40, and an aperture array 45 arranged in a housing 102. With. The head-up display device 100 includes a plane mirror 51 and a magnifying mirror 52.

  The laser light L emitted from the laser light source unit 10 enters the scanning unit 20. The scanning unit 20 scans the incident laser light L. Here, it is assumed that the traveling direction of the laser light L is the Z axis, the left-right direction of the observer's eye is the X axis (horizontal direction), and the direction perpendicular to the X axis and the Z axis is the Y axis (vertical direction). The scanning unit 20 draws the display image M on the first microlens array 40 by scanning the laser light L.

  The laser beam L scanned by the scanning unit 20 enters the refracting unit 30. The refracting unit 30 controls the incident angle of the laser light L on the first microlens array 40. The laser beam L emitted from the refracting unit enters the first microlens array 40.

The first microlens array 40 diverges the incident laser light L. The first microlens array 40 functions as a transmission screen that displays the display image M.
The laser light L (display light representing the virtual image V of the display image M) emitted from the first microphone lens array 40 passes through the aperture array 45. The aperture array 45 absorbs stray light in the housing 102, light incident from the outside of the housing 102, and the like, and uniformizes display light representing the virtual image V of the display image M.

  The laser light L (display light representing the virtual image V of the display image M) that has passed through the aperture array 45 is reflected in the order of the plane mirror 51 and the magnifying mirror 52, and is emitted from the emission unit 101 of the housing 102. Laser light L emitted from the emission unit 101 (display light representing the virtual image V of the display image M) enters the windshield 201. The windshield 201 reflects incident laser light L (display light representing the virtual image V of the display image M). The reflected laser light L (display light representing the virtual image V of the display image M) reaches the observer's eye 1.

  A specific configuration of the head-up display device 100 will be described.

(Laser light source)
FIG. 3 shows the configuration of the laser light source unit 10. The laser light source unit 10 combines R (red), G (green), and B (blue) laser beams and emits a laser beam L. The laser light source unit 10 includes a laser diode (red LD) 11r that emits red laser light, a laser diode (green LD) 11g that emits green laser light, and a laser diode (blue LD) 11b that emits blue laser light. . Further, condensing lenses 12r, 12g, and 12b that condense the laser beams emitted from the red LD 11r, the green LD 11g, and the blue LD 11b, and apertures 13r, 13g, and 13b that shape the beam shape of each laser beam, It arrange | positions on the optical path of the laser beam radiate | emitted from LD. Further, the laser light source unit 10 includes dichroic mirrors 14 and 15 that combine laser beams emitted from the red LD 11r, the green LD 11g, and the blue LD 11b.

Taking an optical system (red laser optical system) composed of a red LD 11r, a condensing lens 12r and an aperture 13r as an example, the red LD 11r, the condensing lens 12r, the aperture 13r, the beam cross-sectional shape of the laser light, and the intensity distribution of the beam cross-section Will be described.
The red LD 11r is arranged such that the beam cross-sectional shape of the emitted red laser light is an ellipse having a long axis in the vertical direction.
The red laser light emitted from the red LD 11r enters the condenser lens 11r. The condenser lens 11r is a lens whose aberration has been corrected so that the red laser light emitted from the red LD 11r is condensed at a predetermined position. That is, the condenser lens 12r converts the laser light emitted from the red LD 11r from divergent light to convergent light.

The red laser light emitted from the condenser lens 12r is incident on the aperture 13r. The aperture 13r has an opening 13ra (FIG. 4). The aperture 13r is composed of a metal plate or the like. The opening 13ra is, for example, a rectangle that is long in the horizontal direction. The shape of the opening 13ra is not limited to a rectangle, but the vertical end of the red laser light emitted from the condenser lens 12r is shielded and the horizontal direction is not shielded (only the vertical beam shape is shaped). If it is)
The size of the opening 13ra is determined so as to have a predetermined numerical aperture (NA) from the wavelength of the red laser light emitted from the red LD 11r and the pitch of the first microlens array 40 described later. To do.

FIG. 5 is a diagram showing changes in the beam cross-sectional shape of the red laser light emitted from the red LD 11r and the intensity distribution of the beam cross-section.
As described above, the cross-sectional shape of the red laser light emitted from the red LD 11r is an ellipse having a long axis in the vertical direction (FIG. 5: a1). Further, the intensity distribution of the beam cross section of the red laser light emitted from the red LD 11r is regarded as a substantially Gaussian distribution in both the horizontal direction and the vertical direction (FIG. 5: a2, a3).

  The red laser light incident on the condenser lens 12r is emitted from the condenser lens 12r as convergent light. In this case, the beam cross-sectional shape of the red laser light emitted from the condenser lens 12r remains an ellipse having a long axis in the vertical direction (FIG. 5: b1). Further, the intensity distribution of the beam cross section of the red laser light emitted from the condensing lens 12r also remains substantially Gaussian in both the horizontal direction and the vertical direction (FIG. 5: b2, b3).

  The red laser light emitted from the condenser lens 12r enters the aperture 13r and passes through the opening 13ra. In this case, the opening 13ra shields the vertical end of the red laser light emitted from the condenser lens 12r and does not shield the horizontal direction, so the beam cross-sectional shape of the red laser light that has passed through the opening 13ra is: The upper and lower parts of an elliptical shape having a long axis in the vertical direction are cut off (FIG. 5: c1). The intensity distribution in the horizontal direction in the beam cross section of the red laser light that has passed through the opening 13ra remains substantially Gaussian because the opening 13ra does not shield the horizontal direction (FIG. 5: c2). On the other hand, in the vertical intensity distribution in the beam cross section of the red laser light that has passed through the opening 13ra, since the opening 13ra shields the end in the vertical direction, both end portions of the Gaussian distribution are lost, and the substantially uniform substantially top It is regarded as a hat-shaped distribution (FIG. 5: c3).

  The optical system composed of the green LD 11g, the condensing lens 12g, and the aperture 13g and the optical system composed of the blue LD 11b, the condensing lens 12b, and the aperture 13b also have the same configuration as the red laser optical system described above. The beam cross-sectional shape of each color laser beam and the intensity distribution of the beam cross-section are the same as in the red laser optical system.

  The dichroic mirrors 14 and 15 are mirrors in which a thin film such as a dielectric multilayer film is formed on a mirror surface. The dichroic mirror 14 is disposed at a predetermined angle on the optical path of the red laser light that has passed through the aperture 13r and the blue laser light that has passed through the aperture 13b. The dichroic mirror 14 transmits blue laser light and reflects red laser light. Therefore, the red laser light that has passed through the aperture 13r and the blue laser light that has passed through the aperture 13b are combined.

  The dichroic mirror 15 is disposed at a predetermined angle on the optical path of the laser light emitted from the dichroic mirror 14 (laser light obtained by combining the red laser light and the blue laser light) and the green laser light that has passed through the aperture 13g. The The dichroic mirror 15 transmits the combined red and blue laser light and reflects the green laser light. Therefore, the green laser light that has passed through the aperture 13g is also multiplexed. Laser light (laser light L) obtained by combining red, green, and blue laser lights is emitted from the dichroic mirror 15.

  As described above, the laser light source unit 10 emits the laser light L obtained by combining the red, green, and blue laser lights. Since the beam cross-sectional shape of the laser beam L and the intensity distribution of the beam cross-section are the same, the beam cross-sectional shape of each color laser beam and the intensity distribution of the beam cross-section are the same. Be the same. That is, the cross-sectional shape of the beam of the laser light L is a shape obtained by cutting off the upper and lower portions of an elliptical shape having a long axis in the vertical direction. Further, the horizontal intensity distribution in the beam cross section of the laser light L is a substantially Gaussian distribution, and the vertical intensity distribution is a substantially top-hat shaped distribution.

  When the red LD 11r, the green LD 11g, and the blue LD 11b are combined and emitted from the dichroic mirror 15, the polarization directions of the laser beams of the respective colors coincide with each other, and the polarization direction depends on the reflectance of the windshield 201. It is determined from sex.

(Scanning part)
The scanning unit 20 includes, for example, a MEMS (Micro Electro Mechanical System) scanner. The MEMS scanner (scanning unit) 20 is disposed on the optical path of the laser light L emitted from the laser light source unit 10.
The MEMS scanner (scanning unit) 20 draws and generates a display image M by scanning the laser light L emitted from the laser light source unit 10. The MEMS scanner (scanning unit) 20 forms one pixel of the display image M by continuously inclining the mirror surface of the MEMS scanner for about 10 nsec in the horizontal direction.

(Refractive part)
The refracting unit 30 is composed of a convex lens or the like. The refracting unit 30 is disposed on the optical path of the laser beam L scanned by the scanning unit 20. The refracting unit 30 applies the laser light L scanned by the scanning unit 20 to the first microlens array 40 at an incident angle corresponding to the scanning position (an angle formed between the normal line of the first microlens array 40 and the laser light L). The laser beam L scanned by the scanning unit 20 is refracted so as to be incident on.

(First microlens array)
As shown in FIG. 6, the first microlens array 40 has a plurality of microlenses 40 a periodically arranged at a pitch of dH1 in the horizontal direction and dV1 in the vertical direction. Further, the plurality of microlenses 40a are formed such that the distance between the microlenses 40a, the step difference, and the like are minimized. Here, the pitch of the microlens array (microlens) is the distance between the centers of adjacent microlenses. In the present embodiment, it is assumed that the horizontal pitch dH1 is greater than or equal to the vertical pitch dV1 (dH1 ≧ dV1). For example, in the first microlens array 40, rectangular microlenses 40 a that are long in the horizontal direction are periodically arranged so that the interval between the microlenses 40 a, steps, and the like are minimized.
In the present embodiment, the horizontal pitch dH1 of the first microlens array 40 corresponds to the size of one pixel of the display image M.

  The first microlens array 40 is in a state where the optical axis AX of the microlens 40a located at the center of the first microlens array 40 and the mirror surface of the MEMS scanner (scanning unit) 20 are not inclined (stationary state). The center of the beam cross section of the laser beam L reflected by the mirror surface in FIG.

  The laser light L incident on the first microlens array 40 is once converged and diverged by the microlens 40a. The first microlens array 40 functions as a transmission screen that displays the display image M because the scanning unit 20 diverges the laser light L that draws the display image M on the first microlens array 40. The divergent laser light L emitted from the first microlens array 40 will be described later.

(Aperture array)
As shown in FIG. 7, the aperture array 45 has a plurality of openings 45a that are periodically arranged in the horizontal and vertical directions in the plane. Each opening 45a makes a pair with each microlens 40a in the first microlens array 40. The aperture array 45 is manufactured by a photolithography technique or the like. A region other than the opening 45a in the aperture array 45 is a light shielding portion 45b. The light shielding part 45b absorbs visible light.

  FIG. 8 shows the arrangement of the first microlens array 40 and the aperture array 45 and the optical path of the laser light L. The aperture array 45 is arranged such that the center of the opening 45 a located at the center of the aperture array 45 is located on the optical axis AX of the microlens 40 a located at the center of the first microlens array 40. In addition, the aperture array 45 and the first microlens array 40 are arranged with a focal length f of the microlens 40a in the first microlens array 40 being separated.

  The size of the opening 45 a of the aperture array 45 is about 1/5 to 1/10 of the size of the micro lens 40 a in the first micro lens array 40. The openings 45a of the aperture array 45 are arranged at a pitch of dHA in the horizontal direction and dVA in the vertical direction. Here, the pitch of aperture arrays (openings) is the distance between the centers of adjacent openings. In the present embodiment, as in the first microlens array 40, the horizontal pitch dHA is greater than or equal to the vertical pitch dVA (dHA ≧ dVA). In addition, the horizontal pitch dHA of the aperture array 45 is equal to or greater than the horizontal pitch dH1 of the first microlens array 40, and the vertical pitch dVA of the aperture array 45 is vertical to the first microlens array 40. The direction pitch is not less than dV1 (dHA ≧ dH1, dVA ≧ dV1).

  In the present embodiment, the optical axis AX of the microlens 40a located at the center of the first microlens array 40 and the mirror in a state where the mirror surface of the MEMS scanner (scanning unit) 20 is not inclined (still state). Since the center of the beam cross section of the laser beam L reflected from the surface is aligned, the incident angle (the incident angle (the laser beam L scanned by the MEMS scanner (scanning unit)) 20 enters the first microlens array 40 ( The angle formed between the normal line of the first microlens array 40 and the laser light L) is larger in the peripheral portion than in the center of the first microlens array 40. Therefore, by setting the pitch of the aperture array 45 to be equal to or larger than the pitch of the first microlens array 40 (dHA ≧ dH1, dVA ≧ dV1), the laser beams condensed by the microlenses 40a in the first microlens array 40 are collected. The condensing point P of the light L is aligned with the positions of the openings 45 a of the aperture array 45. Thereby, the laser light L condensed by each microlens 40a passes through each opening 45a of the aperture array 45 with high efficiency (FIG. 9).

  On the other hand, the light shielding portion 45b of the aperture array 45 absorbs visible light. Therefore, external light that has entered the housing 102 from the outside of the housing 102, internally reflected light in the first microlens array 40, and the like are absorbed by the light shielding portion 45 b of the aperture array 45. Therefore, the head-up display device 100 reduces external light reflection and internal reflection of the laser light L, uniformizes the laser light L emitted from the first microlens array 40, and a virtual image of the display image M with high display quality. V can be displayed.

(Plane mirror, magnifying mirror)
The plane mirror 51 is a planar total reflection mirror. The laser beam L (display light representing the virtual image V of the display image M) that has passed through the opening 45a of the aperture array 45 is disposed on the optical path. The plane mirror 51 reflects display light representing the virtual image V of the display image M to the magnifying mirror 52.
The magnifying mirror 52 is, for example, a concave mirror. The magnifying mirror 52 is disposed on the optical path of the display light representing the virtual image V of the display image M reflected by the plane mirror 51, and reflects the display light representing the virtual image V of the display image M to the windshield 201. Since the magnifying mirror 52 is a concave mirror, the virtual image V of the display image M is a virtual image in which the display image M is enlarged.

  Display light representing the virtual image V of the display image M reflected by the magnifying mirror 52 is emitted from the emission unit 101. The display light representing the virtual image V of the display image M emitted from the emission unit 101 is reflected by the windshield 201, and the virtual image V of the display image M is formed in front of the windshield 201. Therefore, an observer or the like of the vehicle 200 can visually recognize the display image M as the virtual image V in the Eyebox 3 that is the viewing area.

(Control part)
The head-up display device 100 further includes a control unit 60. The control unit 60 includes a microcomputer 61, an output control unit 62, a not-shown DAC (Digital to Analog Converter), and the like (FIG. 10). The DAC converts analog data received from the color sensor 70 and the light sensor 75 into digital data and supplies the digital data to the microcomputer 61.

The color sensor 70 is provided, for example, on the surface of the first microlens array 40 on which the laser light L is incident (FIG. 2), and detects the red, green, and blue light intensities in the laser light L. The color sensor 70 supplies analog data of the detected light intensity to the DAC. The installation position of the color sensor 70 is arbitrary as long as the light intensity is detected within a predetermined range.
The light sensor 75 is provided, for example, in the periphery of the emitting unit 101 (FIG. 2). The light sensor 75 detects external light intensity. The light sensor 75 supplies analog data of the detected external light intensity to the DAC. The installation position of the light sensor 75 is arbitrary as long as the external light intensity is detected within a predetermined range.

  The microcomputer 61 controls various operations in the head-up display device 100. The microcomputer 61 acquires image data for displaying the display image M from a storage unit (not shown) by LVDS (Low Voltage Differential Signal) communication or the like. The storage unit stores in advance a predetermined operation program, position data indicating the position where the color sensor 70 is installed, and the like.

For example, the microcomputer 61 controls the operation of the head-up display device 100 as follows based on the stored operation program.
a) The microcomputer 61 generates control data. The microcomputer 61 drives the red, green, and blue LDs 11r, 11g, and 11b through the output control unit 62 by outputting the generated control data to the output control unit 62. The control data generated here is generated based on the digital data of the light intensity of each color in the laser light L received from the color sensor 70 and converted by the DAC. The control data is control data for setting the light intensity of the laser light of each color emitted from the red, green, and blue LDs 11r, 11g, and 11b to the intensity required by the video signal based on the image data for displaying the display image M. Etc.
b) The microcomputer 61 drives the MEMS scanner (scanning unit) 20 via the MEMS driver 80.
c) The microcomputer 61 supplies control data to the output control unit 62 at a predetermined timing and acquires light intensity data from the color sensor 70.

  The output control unit 62 controls the respective outputs of the red, green, and blue LDs 11r, 11g, and 11b based on the control data supplied from the microcomputer 61, and drives the red, green, and blue LDs 11r, 11g, and 11b.

(Laser light emitted from the first microlens array)
The laser light L incident on the first microlens array 40 is condensed by the microlens 40a. The beam diameter of the laser light L incident on the first microlens array 40 includes the size of the opening 13ra of the aperture 13r of the laser light source unit 10, the size of the opening of the aperture 13g, and the size of the opening of the aperture 13b. , And the distance between the apertures 13r, 13g, and 13b and the first microlens array 40. The laser light L collected by the microlens 40 a passes through the opening 45 a of the aperture array 45 and diverges. The diverged laser light L illuminates the Eyebox 3 via the plane mirror 51, the magnifying mirror 52, and the windshield 201.

In the present embodiment, the laser light L incident on the first microlens array 40 has a horizontal beam diameter Drh larger than the horizontal pitch dH1 of the first microlens array 40, as shown in FIG. The first microlens array 40 is irradiated so that the beam diameter Drv in the vertical direction is smaller than or equal to the vertical pitch dV1 of the first microlens array 40 (Drh <dH1, Drv ≧ dV1). Here, the beam diameter of the laser light is the diameter of the laser light beam defined at a position where the intensity is 1 / e ² (13.5%) with respect to the peak intensity of the beam.

(Vertical direction)
The beam diameter Drv in the vertical direction of the laser light L is equal to or greater than the vertical pitch dV1 of the first microlens array 40, and the microlens 40a is formed so that the distance between the microlenses 40a, the step difference, and the like are minimized. Therefore, the laser light L is incident on the plurality of microlenses 40a in the vertical direction. In the vertical direction, the laser light L incident on the plurality of microlenses 40a passes through the openings 45a of the aperture array 45 corresponding to the microlenses 40a, diverges, and illuminates the Eyebox 3. Since the diverged laser light L is incident on the plurality of microlenses 40a in the vertical direction, the laser light L interferes in the vertical direction due to the periodicity of the first microlens array 40 and the coherence of the laser light L. In such a case, generally, interference fringes are formed on Eyebox 3 due to interference (FIG. 12).

FIG. 13 is a diagram for explaining the interfered laser light L (red) that forms a bright portion of the interference fringes in the vertical direction. FIG. 14 shows the intensity distribution in the vertical direction in the beam section of the laser light L on Eyebox 3 in the present embodiment. In FIG. 13, the scanning unit 20, the plane mirror 51, the magnifying mirror 52, and the like are omitted for simplification.
In the present embodiment, by optimizing the distance between the apertures 13r, 13g, 13b and the first microlens array 40 in the laser light source unit 10, interference occurs to form a bright portion in the interference fringes on the Eyebox 3. The beam diameter of the laser beam L is enlarged or reduced, and the distance between the bright part and the bright part in the interference fringe on Eyebox 3 is made close. That is, the diffraction angle θd and the divergence angle φ of the interfering laser light L forming the bright part are made substantially the same (FIG. 13). Specifically, since the convergence angle η of the laser light L incident on the first microlens array 40 and the divergence angle φ of the interfered laser light L forming the bright portion can be regarded as the same, the convergence angle η ( The distance between the apertures 13r, 13g, and 13b and the first microlens array 40 so that the NA of the apertures 13r, 13g, and 13b) and the diffraction angle θd of the interfering laser light L that forms the bright portion are substantially the same. The vertical pitch dV1 of the first microlens array 40 is selected. For example, in the case of green laser light, NA = 0.005 of the aperture 13g is selected for the vertical pitch dV1 of the first microlens array 40 = 50 μm.

  Further, the intensity distribution in the vertical direction in the beam cross section of the interfered laser light L forming the bright portion can be regarded as a substantially top-hat-shaped distribution in the same manner as the laser light L emitted from the laser light source unit 10.

  Therefore, in the present embodiment, the distance between the apertures 13r, 13g, 13b and the first microlens array 40 and the pitch dV1 in the vertical direction of the first microlens array 40 are selected, and the interference fringes on the Eyebox 3 By setting the distance between the bright part and the bright part to be equal to or less than the minimum diameter (2 mm) of the human pupil, even when the pupil of the observer or the like moves in the vertical direction in Eyebox 3, uneven brightness and uneven color are obtained. It can be suppressed (FIG. 14).

(horizontal direction)
The horizontal beam diameter Drh of the laser light L is smaller than the pitch dH1 of the first microlens array 40, as shown in FIG. Further, the horizontal intensity distribution in the beam cross section of the laser light L remains a Gaussian distribution. Since the horizontal beam diameter Drh of the laser light L is smaller than the pitch dH1 of the first microlens array 40, no interference of the laser light L occurs in the horizontal direction.

  In the horizontal direction, the laser light L incident on the microlens 40a passes through the opening 45a of the aperture array 45 corresponding to each microlens 40a, diverges, and illuminates the Eyebox 3. Also in Eyebox 3, the horizontal intensity distribution in the beam cross section of the laser light L remains a Gaussian distribution.

  In the present embodiment, the MEMS scanner (scanning unit) 20 continuously tilts the mirror surface of the MEMS scanner for about 10 nsec in the horizontal direction to form one pixel of the display image M. Accordingly, the laser light L incident on the first microlens array 40 moves by one of the microlenses 40a in the horizontal direction in order to form one pixel. In this case, while the laser beam L moves in the horizontal direction, the horizontal intensity distribution in the beam cross section of the laser beam L also moves in the Eyebox 3 (FIG. 15). When the intensity distribution of the beam cross section in the horizontal direction as shown in FIG. 15 is integrated during the time required for the laser light L to move by one micro lens 40a (one pixel), the intensity distribution of the substantially top hat shape in the horizontal direction of Eyebox 3 is obtained. Can be obtained (FIG. 16). Therefore, in the present embodiment, even when the pupil of an observer or the like moves in the Eyebox 3 in the horizontal direction, luminance unevenness and color unevenness can be suppressed.

As described above, in the present embodiment, the laser light L that suppresses luminance unevenness and color unevenness in the horizontal and vertical directions in the Eyebox 3 with a simple configuration using the apertures 13r, 13g, 13b, and the aperture array 45. (Display light representing the virtual image V of the display image M) is irradiated. Further, in the present embodiment, the shielding of the laser beam L by the apertures 13r, 13g, and 13b is limited to the vertical direction, so that there is little light loss and the light utilization efficiency is high. Furthermore, in the present embodiment, since the laser light L is emitted by the first microlens array 40, the generation of speckles can be suppressed.
Therefore, an observer or the like of the vehicle 200 can visually recognize the virtual image V of the display image M without speckles, luminance unevenness, and color unevenness.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a second microlens array 90 is provided in place of the aperture array 45 in the first embodiment. Other configurations are the same as those in the first embodiment.
The second microlens array 90 has a plurality of microlenses 90a arranged in the horizontal and vertical directions in the plane (FIG. 17). In the second microlens array 90, the optical axis of the microlens 90a located at the center of the second microlens array 90 coincides with the optical axis AX of the microlens 40a located at the center of the first microlens array 40. To be arranged. Further, the second microlens array 90 is spaced apart so that the lens curved surface of the microlens 90a is positioned at the focal point of the microlens 40a in the first microlens array 40 (FIG. 18).

  In the second microlens array 90, the microlenses 90a are arranged at a pitch of dH2 in the horizontal direction and dV2 in the vertical direction. The horizontal and vertical pitches dH2 and dV2 in the second microlens array 90 correspond to the horizontal and vertical pitches dHA and dVA of the aperture array 45 in the first embodiment, respectively. That is, the horizontal pitch dH2 of the second microlens array 90 is greater than or equal to the horizontal pitch dH1 of the first microlens array 40, and the vertical pitch dV2 of the second microlens array 90 is The pitch dV1 in the vertical direction of one microlens array 40 is not less than dV1 (dH2 ≧ dH1, dV2 ≧ dV1). As a result, the laser light L collected by each microlens 40a in the first microlens array 40 diverges efficiently and uniformly by each microlens 90a in the second microlens array 90.

  In the present embodiment, since the lens curved surface of each microlens 90a of the second microlens array 90 is arranged at the focal point of each microlens 40a in the first microlens array 40, the laser light L is uniformly distributed. It can diverge | emit and can make the illumination distribution of Eyebox3 uniform. Other effects are the same as those of the first embodiment.

  The first microlens array 40 and the second microlens array 90 may be integrated or separate. For example, as shown in FIG. 19, the first microlens array 40 and the second microlens array 90 manufactured separately may be assembled by a support member 91. The convex surface of each microlens 40a of the first microlens array 40 and the convex surface of each microlens 90a of the second microlens array 90 may be arranged to face each other (FIG. 20A). Further, the convex surface of each microlens 40a of the first microlens array 40 and the convex surface of each microlens 90a of the second microlens 90 may be arranged in the same direction (FIG. 20B). The space between the first microlens array 40 and the second microlens array 90 may be an air layer, and has a refractive index different from that of the first and second microlens arrays 40 and 90. It may be filled with material. Further, the first microlens array 40 and the second microlens array 90 that are produced separately are bonded to each other with a light-transmitting property having substantially the same refractive index as that of the first and second microlens arrays 40 and 90. You may make it adhere | attach with an agent etc.

According to the head-up display device 100 described in the above embodiment,
It is possible to provide the head-up display device 100 that displays a display image without speckles and luminance unevenness with a simple configuration. This is realized by the following configuration.

The head-up display device 100 includes:
A laser light source unit 10 for emitting laser light L;
A scanning unit 20 that scans the laser light L emitted from the laser light source unit 10;
A first microlens array 40 on which a plurality of microlenses 40a are arranged, on which the scanned laser light L enters the scanning unit 20, and
The horizontal pitch dH1 of the first microlens array 40 is larger than the horizontal beam diameter Drh of the laser light L incident on the first microlens array 40;
The vertical pitch dV1 of the first microlens array 40 is equal to or smaller than the vertical beam diameter Drv of the laser light L incident on the first microlens array 40.

  The horizontal pitch dH1 of the first microlens array 40 may be greater than or equal to the vertical pitch dV1 of the first microlens array 40.

An aperture array 45 in which a plurality of openings 45a are arranged, on which the laser light L emitted from the first microlens array 40 is incident;
The horizontal pitch dHA of the aperture array 45 is not less than the horizontal pitch dH1 of the first microlens array 40, and
The vertical pitch dVA of the aperture array 45 may be greater than or equal to the vertical pitch dV1 of the first microlens array 40.

A second microlens array 90 in which a plurality of microlenses 90a are arranged on which the laser light L emitted from the first microlens array 40 is incident;
The horizontal pitch dH2 of the second microlens array 90 is not less than the horizontal pitch dH1 of the first microlens array 40, and
The vertical pitch dV2 of the second microlens array 90 may be greater than or equal to the vertical pitch dV1 of the first microlens array 40.

  The laser light L emitted from the laser light source unit 10 may have a substantially Gaussian intensity distribution in the horizontal direction and a substantially top-hat intensity distribution in the vertical direction.

A refracting unit 30 is disposed between the scanning unit 20 and the first microlens array 40 and emits the laser light L scanned by the scanning unit 20 to the first microlens array 40.
The angle of the laser light L emitted from the refraction unit 30 with respect to the normal line of the first microlens array 40 is larger at the end of the first microlens array 40 than at the center of the first microlens array 40. Also good.

  The condensing lenses 12r, 12g, and 12b in the laser light source unit 10 may have an aspherical shape such as a toroid as a curved surface shape. Since the condensing lenses 12r, 12g, and 12b have an aspherical shape, the intensity distribution of the beam cross section in each color laser beam passing through the apertures 13r, 13g, and 13b can be optimized. In addition, the beam diameter of the laser light L incident on the first microlens array 40 can be optimized.

  The first microlens array 40 and the aperture array 45 may be integrated or separate.

  A window member made of an acrylic resin or the like may be disposed on the emission unit 101. The window member is formed into a curved shape and attached to the emitting portion 101 by attachment or the like. The window member transmits the laser light L reflected by the magnifying mirror 52.

  In the above description, in order to facilitate the understanding of the present invention, the description of known unimportant technical matters is appropriately omitted.

1 Eye of an observer 3 Eyebox 3
DESCRIPTION OF SYMBOLS 10 Laser light source part 11r, 11g, 11b Laser diode 12r, 12g, 12b Condensing lens 13r, 13g, 13b Aperture 13ra Aperture opening 14 Dichroic mirror 15 Dichroic mirror 20 Scanning part (MEMS scanner)
DESCRIPTION OF SYMBOLS 30 Refraction part 40 1st micro lens array 40a Micro lens in 1st micro lens array 45 Aperture array 45a Aperture array opening 45b Aperture array light shielding part 51 Planar mirror 52 Magnifying mirror 60 Control part 61 Microcomputer 62 Output control part 70 Color sensor 75 Light sensor 80 MEMS driver 90 Second microlens array 90a Microlens in second microlens array 91 Support member 100 Head-up display device 101 Emitting unit 102 Housing 200 Vehicle 201 Windshield dH1 First micro Horizontal pitch of lens array dV1 Vertical pitch of first microlens array dH2 Horizontal pitch of second microlens array dV2 Second Vertical pitch of micro lens array dHA Horizontal pitch of aperture array dVA Vertical pitch of aperture array Drh Horizontal beam diameter of laser light Drv Vertical beam diameter of laser light AX of first micro lens array Optical axis of microlens positioned at the center f Focal length of microlens in first microlens array L Laser beam M Display image P Condensing point V Virtual image θd Diffraction angle of interfering laser beam forming bright part φ Bright part Divergence angle of interfering laser light forming η Convergence angle of laser light

Claims (6)

A laser light source that emits laser light;
A scanning unit that scans laser light emitted from the laser light source unit;
A first microlens array in which a plurality of microlenses are arranged, on which the scanned laser light is incident on the scanning unit,
The horizontal pitch of the first microlens array is larger than the horizontal beam diameter of the laser light incident on the first microlens array,
The vertical pitch of the first microlens array is equal to or less than the vertical beam diameter of the laser light incident on the first microlens array.
A head-up display device. The horizontal pitch of the first microlens array is equal to or greater than the vertical pitch of the first microlens array.
The head-up display device according to claim 1. An aperture array in which a plurality of openings are arranged, on which laser light emitted from the first microlens array is incident;
The horizontal pitch of the aperture array is equal to or greater than the horizontal pitch of the first microlens array,
The vertical pitch of the aperture array is equal to or greater than the vertical pitch of the first microlens array.
The head-up display device according to claim 1 or 2. A second microlens array in which a plurality of microlenses are arranged, on which laser light emitted from the first microlens array is incident;
The horizontal pitch of the second microlens array is greater than or equal to the horizontal pitch of the first microlens array,
The vertical pitch of the second microlens array is greater than or equal to the vertical pitch of the first microlens array.
The head-up display device according to claim 1 or 2. The laser light emitted from the laser light source unit has a substantially Gaussian intensity distribution in the horizontal direction and a substantially top-hat intensity distribution in the vertical direction.
The head-up display device according to claim 1, wherein the head-up display device is a head-up display device. A refracting unit disposed between the scanning unit and the first microlens array, and emitting a laser beam scanned by the scanning unit to the first microlens array;
The angle of the laser beam emitted from the refracting unit with respect to the normal line of the first microlens array is larger at the end of the first microlens array than at the center of the first microlens array.
The head-up display device according to claim 1, wherein the head-up display device is a head-up display device.

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