JP7318604B2 - virtual image display - Google Patents

Description

The present disclosure relates to virtual image display devices.

2. Description of the Related Art A virtual image display device that reflects display light with a translucent member and visually displays a virtual image of the display light is conventionally known.

For example, the virtual image display device disclosed in Patent Document 1 includes a display that forms an image by transmission of illumination light condensed by an illumination lens and emits display light of the image. Here, the illuminating lens has an arrangement structure in which a plurality of lens surface portions for condensing illumination light by refraction are intermittently formed in a direction orthogonal to each optical axis. As a result, it is possible to suppress illuminance unevenness in the lighting of the display.

Japanese Patent No. 6237249

However, in the virtual image display device disclosed in Patent Document 1, a discontinuous surface whose surface shape changes discontinuously is formed at the boundary between the array structures. As a result, depending on the position of the viewer's eyepoint, the illumination light incident on the boundary of the array structure produces sharp edge light, which could lead to deterioration of the illumination quality that affects the visibility of the virtual image. .

Accordingly, an object of the present disclosure is to provide a virtual image display device that enhances the visibility of virtual images.

Technical means of the present disclosure for solving the problems will be described below. It should be noted that the symbols in parentheses described in the claims and this column indicate the correspondence with specific means described in the embodiments described in detail later, and limit the technical scope of the present disclosure. not something to do.

One aspect of the present disclosure is
A virtual image display device (100) for visibly displaying a virtual image (VRI) by the display light by reflecting the display light with a translucent member (3),
a lighting unit (40) that emits white illumination light;
an image forming unit (20) that forms an image by transmission of illumination light and emits display light of the image;
a light collecting unit (30) for collecting the illumination light toward the image forming unit;
The image forming unit has a plurality of pixel regions (212) arranged,
The light collection unit
A plurality of diffusing surfaces (313, 3313) are arranged so as to form a wave-like diffusing surface (313, 3313) that diffuses illumination light within a range within an angle space (θ) for condensing illumination light individually incident on each pixel region. a front stage lens portion (312, 3312);
In the rear stage of each front lens section , the refracting surface sections (323, 325) for condensing the illumination light in the angle space, which is individually incident on each pixel region, by refraction are arranged in the orthogonal direction (Xc, Yc) and a plurality of rear lens portions (322) arranged so as to be intermittently formed.

In the plurality of rear-stage lens portions arranged in the light-condensing unit of such an aspect, the refracting surface portion is arranged so that the illumination light in the angle space , which is individually incident on each pixel region of the plurality of arrays in the image forming unit, is condensed by refraction. are intermittently formed in the direction perpendicular to the optical axis. Therefore, in the plurality of front-stage lens portions arranged in the light-condensing unit of one aspect, the diffusing surface is formed so as to diffuse the illumination light within the range of the angular space for condensing the illumination light individually incident on each pixel region. It is formed. According to this, the illumination light that has undergone the diffusing and condensing action in each front lens section apparently spreads within the angular space and enters the corresponding rear lens section. As a result, edge light that shines sharply due to the boundaries between the rear lens portions is less likely to occur. Therefore, it is possible to improve the visibility of the virtual image by increasing the illumination quality.

1 is a schematic diagram showing the overall configuration of a virtual image display device according to a first embodiment; FIG. 2 is a cross-sectional view showing the detailed configuration of the virtual image display device according to the first embodiment; FIG. FIG. 3 is a view taken along line III-III in FIG. 2; FIG. 3 is a view taken along line IV-IV in FIG. 2; 3 is a perspective view of the front stage lens array of FIG. 2; FIG. 3 is an enlarged sectional view of FIG. 2; FIG. FIG. 3 is a view taken along line VII-VII of FIG. 2; 3 is an enlarged cross-sectional view taken along line VIII-VIII of FIG. 2; FIG. 3 is an enlarged sectional view of FIG. 2; FIG. FIG. 3 is a view taken along line XX of FIG. 2; 4 is a schematic diagram for explaining an illumination example of the image forming panel of FIG. 3; FIG. FIG. 4 is a perspective view of a front lens array according to a second embodiment; 3 is a sectional view showing the virtual image display device according to the third embodiment corresponding to FIG. 2; FIG. FIG. 7 is a sectional view showing the virtual image display device according to the third embodiment corresponding to FIG. 6; FIG. 3 is a sectional view showing a modification of FIG. 2; 16 is an enlarged sectional view of FIG. 15; FIG. FIG. 3 is a sectional view showing a modification of FIG. 2; FIG. 3 is a sectional view showing a modification of FIG. 2;

A plurality of embodiments will be described below with reference to the drawings. Note that redundant description may be omitted by assigning the same reference numerals to corresponding components in each embodiment. Moreover, when only a part of the configuration is described in each embodiment, the configurations of the other embodiments previously described can be applied to the other portions of the configuration. Furthermore, not only the combinations of the configurations explicitly specified in the description of each embodiment, but also the configurations of the multiple embodiments can be partially combined even if they are not explicitly specified unless there is a particular problem with the combination.

As shown in FIG. 1, the virtual image display device of the first embodiment is a head-up display (hereinafter referred to as HUD) that is configured to be mounted on a vehicle 1 and accommodated in an instrument panel 2 of the vehicle 1. 100. Here, the vehicle 1 is understood in a broad sense to include various vehicles such as automobiles, railroad vehicles, aircraft, ships, and non-moving game cabinets. In particular, the vehicle 1 of this embodiment is a four-wheel automobile. The front, rear, up, down, left, and right directions of the HUD 100 are defined with respect to the vehicle 1 on the horizontal plane.

The HUD 100 projects image display light toward the windshield 3 of the vehicle 1 . As a result, the display light reflected by the windshield 3 reaches the visible area EB set in the interior of the vehicle 1 . An occupant whose eye point EP is positioned in the visual recognition area EB in the interior of the vehicle 1 perceives the display light that has reached the visual recognition area EB as a virtual image VRI. In this way, the HUD 100 displays a virtual image VRI that can be visually recognized by a viewer (hereinafter simply referred to as a viewer) 4 who is an occupant of the vehicle 1, thereby making it possible for the viewer 4 to recognize various types of information. . Various types of information displayed by the HUD 100 as a virtual image VRI include, for example, information indicating the state of the vehicle 1 such as vehicle speed and remaining amount of fuel, visibility assistance information, road information, navigation information, and the like.

The visible region EB is a spatial region that can be visually recognized by the viewer 4 when the virtual image VRI displayed by the HUD 100 satisfies a predetermined specification (for example, the entire virtual image VRI has a predetermined luminance or more). Also called a box. The visual recognition area EB is typically set so as to overlap the eyelip set on the vehicle 1 . The eyelip is set in a virtual ellipsoidal shape based on the eye range that statistically represents the spatial distribution of the eyepoints EP of the viewer 4 .

The windshield 3 is a translucent member made of, for example, glass or synthetic resin and formed into a translucent plate. The windshield 3 is positioned above the instrument panel 2 to separate the interior and exterior of the vehicle 1 . The windshield 3 is inclined so as to be spaced apart from the instrument panel 2 from the front to the rear. The rear surface of the windshield 3, which faces the room, forms a smooth concave or flat reflecting surface 3a on which display light projected from the HUD 100 is reflected.

The windshield 3 may be provided with a reflective holographic optical element so as to utilize diffraction reflection with interference fringes instead of surface reflection. Instead of the windshield 3, a combiner as a translucent member may be installed inside the vehicle 1 so that the combiner is provided with the reflecting surface 3a.

As shown in FIG. 1, the HUD 100 includes a light guiding unit 10, an image forming unit 20, a condensing unit 30, and an illumination unit 40. As shown in FIG.

The light guide unit 10 constitutes an optical path L from the image forming unit 20 to the windshield 3 . The light guide unit 10 guides display light projected from the image forming unit 20 toward the windshield 3 . The light guiding unit 10 preferably has an enlarging action of enlarging the image formed by the image forming unit 20 to the virtual image VRI visually recognized by the viewer 4 by a predetermined optical magnification. This is because the magnifying action of the light guide unit 10 contributes to miniaturization.

The light guide unit 10 having such functions includes at least one optical member 11 . The light guide unit 10 is configured by combining a plane mirror (or a curved mirror) 11a and a concave mirror 11b as optical members 11 one by one. Here, the concave mirror 11b provides the above-described magnifying action. In addition, for example, the light guide unit 10 may be configured by combining one convex mirror and one concave mirror as the optical member 11, or may be configured by one concave mirror as the optical member 11. good. The optical member 11 that constitutes the light guide unit 10 may be fixed or movable.

The image forming unit 20 forms an image that can be formed as a virtual image VRI outside the vehicle 1 and emits display light of the formed image toward the light guide unit 10 . As shown in FIGS. 1 and 2, the image forming unit 20 includes an image display panel 21 and a diffusion panel 22. As shown in FIG.

The image display panel 21 is formed in a plate shape as a whole. The image display panel 21 is a transmissive TFT liquid crystal panel using thin film transistors. The image display panel 21 is of an active matrix type having a plurality of two-dimensionally arranged liquid crystal pixels. Illumination light from the illumination unit 40 is incident on the incident surface 210 , which is one side of the image display panel 21 , through the light collection unit 30 . Image display light is emitted toward the light guide unit 10 on the optical path L from the exit surface 211 on the opposite side of the image display panel 21 . The image display panel 21 displays and forms an image that becomes this display light.

In the image display panel 21 having such functions, a pair of flat polarizers and a liquid crystal layer sandwiched between the polarizers are laminated in the plate thickness direction. Each polarizer has a transmission axis and a cutoff axis that are orthogonal to each other along both surfaces 210 and 211 of the image display panel 21 . Each polarizer transmits polarized light at azimuthal angles of the transmission axis and absorbs polarized light at azimuthal angles of the block axis. The liquid crystal layer is configured to be able to adjust the polarization of illumination light to be transmitted according to the voltage applied to each liquid crystal pixel. An image is formed by adjusting the ratio of light passing through the polarizer on the exit side, ie, the transmittance, by adjusting the polarization in the liquid crystal layer for each liquid crystal pixel. Particularly in the image display panel 21, a color image can be formed by providing a color filter for each liquid crystal pixel.

As shown in FIGS. 2 and 3, the image display panel 21 is provided with a plurality of pixel regions 212 that are two-dimensionally arranged in predetermined numbers in Xa and Ya directions that are orthogonal to each other. Each pixel area 212 is defined as a rectangular image forming area in which a plurality of liquid crystal pixels are arranged two-dimensionally in the Xa direction and the Ya direction. The number of arrays of pixel regions 212 in the Xa direction may be different from the number of arrays of pixel regions 212 in the Ya direction; In the first embodiment shown in , the "less" configuration is adopted.

As shown in FIG. 1, the diffusion panel 22 is made of a rigid transparent material such as glass or resin and formed in a plate-like or thin-film shape as a whole. The diffusion panel 22 is arranged substantially parallel along the entrance surface 210 of the image display panel 21 . The diffusion panel 22 diffuses illumination light incident on the image display panel 21 . Incidentally, the diffusion panel 22 may be configured integrally with the image display panel 21 by providing the incident surface 210 of the image display panel 21 with minute irregularities.

The light collecting unit 30 shown in FIGS. 1 and 2 collects the illumination light from the illumination unit 40 toward the image forming unit 20 . The condensing unit 30 includes a front lens array 31 and a rear lens array 32 .

As shown in FIGS. 2 and 4, the front-stage lens array 31 is made of a rigid transparent material such as glass or resin and formed in a plate shape as a whole. The front-stage lens array 31 is a plano-convex lens array. The front lens array 31 has a plurality of front lens portions 312 arranged two-dimensionally in a predetermined number each in the Xb direction and the Yb direction that are orthogonal to each other. The number of arrays of the front-stage lens units 312 in the Xb direction matches the number of arrays of the pixel regions 212 in the Xa direction. The number of arrays of front-stage lens units 312 in the Yb direction matches the number of arrays of pixel regions 212 in the Ya direction. With these configurations, each front lens section 312 is associated with one of the pixel regions 212 at 1:1.

Illumination light from the illumination unit 40 is incident on the front incidence surface 310 that is one side of the front lens portion 312 . Illumination light incident on the front entrance surface 310 is emitted toward the rear lens array 32 from the front exit surface 311 , which is the opposite surface of each front lens portion 312 .

A front entrance surface 310 of each front lens portion 312 shown in FIGS. 2, 5, and 6 has a planar shape substantially perpendicular to the optical axis Al orthogonal to the Xb direction and the Yb direction. The front exit surface 311 of each front lens portion 312 forms a composite surface structure in which the diffusion surface 313 is combined with the virtual base surface Sb. As shown in FIG. 6, the virtual base surface Sb defined for each front lens portion 312 has a convex shape that smoothly curves in any direction including the Xb direction and the Yb direction. Each front-stage lens unit 312 converges the emitted illumination light toward the rear-stage lens array 32 within the angle space θ according to the convex virtual base surface Sb.

A function Zb that expresses the convexity of the virtual base surface Sb in order to exhibit such a light condensing effect is given by the following equation 1, for example. In Equation 1, c is the curvature given to the convex surface. In Equation 1, r is a radius vector (that is, radius) from the optical axis Al for any point on the convex surface. k in Equation 1 is a conic constant. αi in Equation 1 is a free-form surface coefficient.

A diffusion surface 313 defined in each front-stage lens portion 312 presents a wavefront shape in which waves travel outward in the Yb direction from a virtual plane α that includes the optical axis Al and spreads in the Xb direction. Each front-stage lens section 312 diffuses the emitted illumination light toward the rear-stage lens array 32 within the angular space θ according to the wavefront-like diffusion surface 313 .

A function Zw representing the wavefront shape of the diffusion surface 313 for exhibiting such a diffusion action is given by the following equation 2, which defines, for example, a one-dimensional plane wavefront. In Equation 2, Ay is the maximum wavefront amplitude in the Yb direction. In Expression 2, Yw is the separation distance in the Yb direction from the virtual plane α with respect to any point on the wavefront. λy in Equation 2 is the wavefront wavelength in the Yb direction.

From the above, the function Zc representing the composite surface structure in which the diffusion surface 313 is combined with the virtual base surface Sb on the front exit surface 311 of each front lens portion 312 is given by the following equation (3). From the configuration up to this point, each front-stage lens unit 312 diffuses the illumination light that individually enters the corresponding pixel region 212 of the image forming unit 20 within the condensing angle space θ. Let it be.

As shown in FIGS. 2 and 7, the rear-stage lens array 32 is made of a hard transparent material such as glass or resin and formed in a plate shape as a whole. The rear-stage lens array 32 has a plurality of rear-stage lens sections 322 that are two-dimensionally arranged in predetermined numbers each in the Xc direction and the Yc direction that are orthogonal to each other. The number of arrays of the rear lens sections 322 in the Xc direction matches the number of arrays of the pixel regions 212 in the Xa direction and the number of arrays of the front lens sections 312 in the Xb direction. The number of arrays of the rear lens sections 322 in the Yc direction matches the number of arrays of the pixel regions 212 in the Ya direction and the number of arrays of the front lens sections 312 in the Yb direction. With these configurations, each rear lens section 322 is associated 1:1 with one of the pixel regions 212 and one of the front lens sections 312 .

Each rear lens portion 322 is positioned behind the corresponding front lens portion 312 and shares the optical axis Al. The image display panel 21 and the diffusion panel 22 are inclined with respect to the optical axis Al of each front lens section 312 and each rear lens section 322 . With this inclined arrangement, the Xa direction of the image display panel 21 is defined to be inclined toward the lens arrays 31 and 32 with respect to the Xb direction of the front lens array 31 and the Xc direction of the rear lens array 32 . On the other hand, the Ya direction of the image display panel 21 is defined substantially parallel to the Yb direction of the front lens array 31 and the Yc direction of the rear lens array 32 .

Illumination light from the corresponding front lens portion 312 is incident on the rear entrance surface 320, which is one surface of each rear lens portion 322 shown in FIGS. Illumination light incident on the rear entrance surface 320 is emitted from the rear exit surface 321 , which is the opposite surface of each rear lens unit 322 , toward the corresponding pixel regions 212 .

The rear entrance surface 320 of each rear lens portion 322 shown in FIG. 8 forms a compound surface structure in which forward refractive surface portions 323 and reverse refractive surface portions 324 are alternately arranged outward in the Xc direction from the optical axis Al. there is The plurality of forward refracting surface portions 323 are formed in stripes (see FIG. 7) that are intermittent in the Xc direction, are spaced apart from each other, and extend along the Yc direction. Each forward refracting surface portion 323 corresponds to one of divided portions obtained by dividing the virtual base surface Si1 in the Xc direction with a constant width. Here, the virtual base surface Si1 is defined to be convex on the incident side, for example, in a convex shape. The plurality of reverse refracting surface portions 324 are formed in stripes (see FIG. 7) that are intermittent in the Xc direction, are spaced apart from each other, and extend in the Yc direction. Each reverse refracting surface portion 324 corresponds to one of divided portions obtained by dividing the virtual base surface Si2 in the Xc direction. Here, the imaginary base surface Si2 is defined to be concave on the exit side, for example, in the shape of a valley-shaped slope. In the composite surface structure as described above, each forward refracting surface portion 323 refracts the illumination light toward the optical axis Al side in the Xc direction and makes it parallel to the optical axis Al, while each reverse refracting surface portion 324 refracts the illumination light forwardly. The light is refracted in the opposite direction to the surface portion 323 and mixed with the collimated light. Note that the collimation means that the illumination light becomes a parallel light flux, and the illumination light does not need to be a perfectly parallel light flux.

In each rear lens portion 322 of the first embodiment, the Xc direction in which the forward refraction surface portions 323 and the reverse refraction surface portions 324 are alternately and intermittently formed corresponds to the horizontal direction Dh (see FIG. 1) of the virtual image VRI. The reverse refractive surface portion 324 of each rear lens portion 322 forms a mountain-shaped boundary 328 with the reverse refractive surface portion 324 of the other rear lens portion 322 adjacent in the Xc direction. A valley-shaped boundary 328 may be formed between the forward refractive surface portion 323 of each rear lens portion 322 and the forward refractive surface portion 323 of another rear lens portion 322 adjacent in the Xc direction.

The rear exit surface 321 of each rear lens portion 322 shown in FIG. 9 has a compound surface structure in which forward refractive surface portions 325 and reverse refractive surface portions 326 are alternately arranged outward in the Yc direction from the optical axis Al. there is The plurality of forward refracting surface portions 325 are formed in stripes (see FIG. 7) that are intermittent in the Yc direction, are spaced apart from each other, and extend along the Xc direction. Each forward refracting surface portion 325 corresponds to one of divided portions obtained by dividing the virtual base surface So1 in the Yc direction. Here, the virtual base surface So1 is defined to be convex toward the exit side, for example, in a convex shape. The plurality of reverse refracting surface portions 326 are formed in stripes (see FIG. 7) that are intermittent in the Yc direction, are spaced apart from each other, and extend in the Xc direction. Each reverse refracting surface portion 326 corresponds to one of divided portions obtained by dividing the virtual base surface So2 in the Yc direction by a constant width. Here, the virtual base surface So2 is defined to be concave on the incident side, for example, in the shape of a valley-shaped slope. In the composite surface structure as described above, each forward refracting surface portion 325 refracts the illumination light toward the optical axis Al side in the Yc direction and makes it parallel to the optical axis Al. The light is refracted in the opposite direction to the surface portion 323 and mixed with the collimated light.

In each rear lens portion 322 of the first embodiment, the Yc direction in which the forward refractive surface portion 325 and the reverse refractive surface portion 326 are alternately and intermittently formed corresponds to the vertical direction Dv (see FIG. 1) of the virtual image VRI. The reverse refractive surface portion 326 of each rear lens portion 322 forms a mountain-shaped boundary 329 with the reverse refractive surface portion 326 of the other rear lens portion 322 adjacent in the Yc direction. A valley-shaped boundary 329 may be formed between the forward refracting surface portion 325 of each rear lens portion 322 and the forward refracting surface portion 325 of another rear lens portion 322 adjacent in the Yc direction.

From the configuration up to this point, the condensing unit 30 is configured such that the front lens section 312 and the rear lens section 322 corresponding to each pixel region 212 of the image forming unit 20 are jointly used to individually input illumination to each pixel region 212 . Each light is condensed.

The illumination unit 40 shown in FIGS. 1 and 2 emits illumination light that illuminates the image forming unit 20 through the light collecting unit 30 . As shown in FIGS. 1, 2, and 10, the illumination unit 40 has a plurality of light source sections 402 that are two-dimensionally arranged in predetermined numbers in the Xd direction and the Yd direction that are orthogonal to each other. The number of arrays of the light source units 402 in the Xd direction matches the number of arrays of the pixel regions 212 in the Xa direction, the number of arrays of the front lens units 312 in the Xb direction, and the number of arrays of the rear lens units 322 in the Xc direction. The number of arrays of the light source units 402 in the Yd direction matches the number of arrays of the pixel regions 212 in the Ya direction, the number of arrays of the front lens units 312 in the Yb direction, and the number of arrays of the rear lens units 322 in the Yc direction. With these configurations, each light source unit 402 is associated 1:1 with one of the pixel regions 212 , one of the front lens units 312 , and one of the rear lens units 322 .

Each light source unit 402 is composed of a light source element that independently emits white illumination light. A light source element of each light source unit 402 is an LED bare chip using, for example, YAG or KSF. The light source element of each light source unit 402 can individually set the illuminance of the illumination light by variably adjusting the emission intensity.

As shown in FIG. 6, the light source element of each light source section 402 is arranged on the common optical axis Al of the corresponding front lens section 312 and rear lens section 322 . Here, the light source element of each light source unit 402 is closer to the condensing unit 30 than the composite focus of the corresponding lens units 312 and 322 in the direction along the optical axis Al of the corresponding front lens unit 312 and rear lens unit 322. are placed. At the same time, the light source element of each light source section 402 is closer to the condensing unit 30 than the focal length Pb of the virtual base surface Sb for the corresponding lens section 312 in the direction along the optical axis Al of the corresponding front lens section 312. are placed.

In each light source unit 402 shown in FIG. 2, the intensity peak directions in which the light emission intensity of each light source element is maximized are set substantially parallel along the optical axis Al of the corresponding front-stage lens unit 312 and rear-stage lens unit 322. there is Under this setting, the Xd direction of the illumination unit 40 is defined substantially parallel to the Xb direction of the front lens array 31 and the Xc direction of the rear lens array 32, and is inclined with respect to the Xa direction of the image display panel 21. defined as On the other hand, the Yd direction of the illumination unit 40 is defined substantially parallel to the Ya direction of the image display panel 21 , the Yb direction of the front lens array 31 , and the Yc direction of the rear lens array 32 .

Illumination light emitted from the light source element of each light source unit 402 from the configuration described above is sequentially incident on the corresponding front lens unit 312 and rear lens unit 322 . That is, the illumination unit 40 emits illumination light individually incident on each corresponding set of the lens sections 312 and 322 from the light source elements of the light source section 402 individually corresponding to the lens sections 312 and 322. .

As shown by outline in FIG. 11, the pixel region 212 corresponding to the light source unit 402 in which the light source element emits light with the maximum intensity is transmissively illuminated with white light with the maximum illuminance. As indicated by dot hatching in FIG. 11, a pixel region 212 corresponding to the light source unit 402 in which the light source element emits light with an intensity lower than the maximum intensity is transilluminated with white light at an intensity lower than the maximum intensity. As shown by cross-hatching in FIG. 11, the pixel region 212 corresponding to the light source unit 402 whose light source element is turned off becomes a substantially non-display region that is not transmissively illuminated.

(Effect)
The effects of the first embodiment described above will be described below.

In the plurality of rear lens sections 322 arranged in the light collection unit 30 of the first embodiment, the illumination light within the angular space θ individually incident on each of the plurality of arranged pixel regions 212 in the image forming unit 20 is condensed by refraction. , the forward refracting surface portion 325 is intermittently formed in the Yc direction, which is the direction perpendicular to the optical axis Al. Therefore, in the front lens section 312 arranged in plurality in the light collecting unit 30 of the first embodiment, the individually incident illumination light is diffused in the angular space θ for condensing the individually incident illumination light for each pixel region 212. A diffusing surface 313 is formed so as to. According to this, the illumination light that has undergone the diffusing and condensing action in each front lens section 312 apparently spreads within the angular space θ and enters the corresponding rear lens section 322 . As a result, edge light that shines sharply due to boundaries 329 between the rear lens portions 322 is less likely to occur. Therefore, it is possible to enhance the visibility of the virtual image VRI by enhancing the illumination quality.

The diffusion surface 313 according to the first embodiment presents a wavy surface in which waves travel in the Yb direction along the Yc direction as the orthogonal direction. As a result, in the front lens section 312, the apparent spread of the illumination light can be promoted by the diffusing and condensing action in the Yb direction along the Yc direction in which the rear lens section 322 is arranged. Therefore, it is possible to effectively suppress the edge light caused by the boundaries 329 between the rear-stage lens portions 322 and improve the visibility of the virtual image VRI.

According to the first embodiment, the Yc direction as the orthogonal direction in which the rear lens units 322 are arranged corresponds to the vertical direction Dv of the virtual image VRI. According to this, in the horizontal direction Dh of the virtual image VRI in which the eyeballs of the viewer 4 viewing the virtual image VRI are easy to move, in the vertical direction Dv of the virtual image VRI in which the eyeballs are difficult to move, the luminance of the display light fluctuates in the first place. hard. Therefore, along with suppression of edge light, it is possible to improve the visibility of the virtual image VRI.

In the illumination unit 40 of the first embodiment, a plurality of light source sections 402 are arranged so that illumination light that individually enters each set of the front lens section 312 and the rear lens section 322 is emitted. As a result, the illumination light from each light source unit 402 that enters the corresponding front lens unit 312 and undergoes the diffusion and condensing action enters the corresponding rear lens unit 322 within the angle space θ, apparently spreading. It will be done. Therefore, the incidence of edge light caused by the boundaries 329 between the rear-stage lens portions 322 can be suppressed for each pixel region 212, and the visibility of the virtual image VRI can be improved.

In each rear lens unit 322 according to the first embodiment, forward refraction surface portions 323 and 325 that collimate the illumination light by refraction, and reverse refraction surface portions 324 and 326 that refract the illumination light and mix it with the collimated light are They are formed alternately in the Xc and Yc directions as orthogonal directions. As a result, the illumination light is diffused and condensed by the front lens section 312, and by the condensing action of the rear lens section 322 accompanied by mixing into collimated light, the boundary 328, 329 between the respective rear lens sections 322. It becomes difficult to generate edge light caused by Therefore, it is possible to effectively suppress such edge light and improve the visibility of the virtual image VRI.

(Second embodiment)
As shown in FIG. 12, the second embodiment is a modification of the first embodiment. In the second embodiment, the number of arrays of elements 212, 312, 322, 402 in the Xa, Xb, Xc, and Xd directions is 12, only the front lens portion 312 is shown.

In such a second embodiment, the size in the horizontal direction (perpendicular to the paper surface in FIG. 1 of the first embodiment) of the visual recognition area EB corresponding to the horizontal direction Dh of the virtual image VRI corresponds to the vertical direction Dv of the virtual image VRI. larger than the vertical size of the visual recognition area EB (the vertical direction in FIG. 1 of the first embodiment). Therefore, it is possible to effectively utilize the horizontally long windshield 3 of the vehicle 1 and provide display of the virtual image VRI with improved visibility in the horizontally long visual recognition area EB.

(Third embodiment)
As shown in FIGS. 13 and 14, the third embodiment is a modification of the second embodiment. In the third embodiment, the front exit surface 311 of each front lens portion 3312 forms a composite surface structure in which a diffusion surface 3313 different from that in the first embodiment is combined with the virtual base surface Sb that is the same as in the first embodiment. are doing. A diffusing surface 3313 defined in each front lens portion 3312 exhibits a wavefront shape in which waves travel outward at least in the Xc direction and the Yb direction from the optical axis Al. Each front-stage lens portion 3312 diffuses the emitted illumination light toward the rear-stage lens array 32 within the angular space θ according to the wavefront diffusion surface 3313 .

A function Zw representing the wavefront shape of the diffusing surface 3313 to exhibit such a diffusing action may be given by the following equation 4, which defines, for example, a two-dimensional plane wavefront. In Equation 4, Ax and Ay are the wavefront maximum amplitudes in the Xb and Yb directions, respectively. In Equation 4, Xw is the separation distance in the Xb direction from the virtual plane β for any point on the wavefront. Here, the virtual plane β is defined orthogonal to the virtual plane α as a plane including the optical axis Al and extending in the Yb direction. In Equation 4, Yw is the separation distance in the Yb direction from the virtual plane α for any point on the wavefront. In Equation 4, λx and λy are wavefront wavelengths in the Xb and Yb directions, respectively.

The function Zw, which describes the wavefront shape of the diffusing surface 3313, may be given by Equation 5 below, which defines, for example, a non-attenuating spherical wavefront. In Expression 5, A is the maximum wavefront amplitude in any direction around the optical axis Al including the Xb and Yb directions. In Expression 5, Xw and Yw are distances in the Xb and Yb directions from the virtual planes β and α regarding arbitrary points on the wavefront. In Equation 5, λ is the wavefront wavelength in any direction around the optical axis Al including the Xb and Yb directions.

The function Zw, which describes the wavefront shape of the diffuser surface 3313, may be given by Equation 6 below, which defines, for example, an attenuated spherical wavefront. In Equation 6, A is the maximum wavefront amplitude in any direction around the optical axis Al including the Xb and Yb directions. In Equation 6, Xw and Yw are distances in the Xb and Yb directions from virtual planes β and α with respect to arbitrary points on the wavefront. In Equation 6, λ is the wavefront wavelength in any direction around the optical axis Al including the Xb and Yb directions.

A function Zw representing the wavefront shape of the diffusing surface 313 may be given by Equations 7-9 below, which define, for example, a sinc wavefront. In Equations 8 and 9, Ax and Ay are the wavefront maximum amplitudes in the Xb and Yb directions, respectively. In Equations 8 and 9, Xw and Yw are the separation distances in the Xb and Yb directions from the virtual planes β and α regarding arbitrary points on the wavefront. In Equations 8 and 9, λx and λy are wavefront wavelengths in the Xb and Yb directions, respectively.

A function Zw representing the wavefront shape of the diffuser surface 3313 may be given by the following equation (10), which defines, for example, a composite two-dimensional plane wavefront. In Equation 10, j is an integer from 1 to N, or a suffix represented by the integer, where N is the composite number of wavefronts. In Equation 10, Axj and Ayj are the wavefront maximum amplitudes in the Xb and Yb directions, respectively. In Equation 10, Xw and Yw are the separation distances in the Xb and Yb directions from the virtual planes β and α regarding arbitrary points on the wavefront. In Equation 10, λx and λy are wavefront wavelengths in the Xb and Yb directions, respectively. Note that when N=1 in Equation 10, it corresponds to Equation 4 above.

Here, in the case of the above equations 4, 7 to 9, 10, the maximum amplitudes Ax, Axj in the Xb direction are different from the maximum amplitudes Ay, Ayj in the Yb direction. or "same". If the maximum amplitudes Ax and Axj are different from the maximum amplitudes Ay and Ayj, the illumination light is given an anisotropic diffusion effect. Therefore, particularly in the third embodiment, the maximum amplitudes Ax and Axj in the Xb direction corresponding to the horizontal direction Dh of the virtual image VRI are larger than the maximum amplitudes Ay and Ayj in the Yb direction corresponding to the vertical direction Dv of the virtual image VRI. “Large” should be set. As a result, in the third embodiment, it is possible to provide a highly visible virtual image VRI by display light obtained by highly efficiently diffusing the illumination light toward the oblong visual recognition area EB described in the second embodiment. .

Furthermore, the diffusing surface 3313 according to the third embodiment presents a wavy surface shape in which waves travel at least in the Xb and Yb directions along the Xc and Yc directions as a pair of mutually orthogonal directions. Thus, in the front lens section 3312, the apparent spread of the illumination light can be promoted by the diffusing and condensing action in the Xb and Yb directions along the Xc and Yc directions in which the rear lens section 322 is arranged. Therefore, it is possible to effectively suppress the edge light caused by the boundaries 328 and 329 between the rear lens portions 322 and improve the visibility of the virtual image VRI.

(Other embodiments)
Although a plurality of embodiments have been described above, the present disclosure is not to be construed as being limited to those embodiments, and can be applied to various embodiments within the scope of the present disclosure. .

In the modification shown in FIGS. 15 and 16, at least one of the rear entrance surface 320 and the rear exit surface 321 in the rear lens array 32 (FIGS. 15 and 16 are examples of only the rear exit surface 321) is composed of a Fresnel lens surface. may have been In this case, instead of at least one of the reverse refraction surface portions 324 and 326, a connection surface portion 327 that connects the forward refraction surface portions 323 or the forward refraction surface portions 325 substantially parallel to the optical axis Al is formed. be done. Further, in this case, at least one of the forward refraction surface portion 323 and the forward refraction surface portion 325 in each post-stage lens portion 322 is the forward refraction surface portion 323 or the forward refraction surface portion of the other post-stage lens portion 322 adjacent in the Xc direction or the Yc direction. 325 form a valley-shaped boundary 328 or boundary 329 .

As shown in FIG. 17 , in a modification, the image display panel 21 and the diffusion panel 22 may be arranged substantially perpendicular to the optical axis Al of each front lens section 312 and each rear lens section 322 . The front-stage lens array 31 of the modified example may be a TIR lens array in which a compound surface structure of diffusion surfaces 313, 3313 and a virtual base surface Sb is formed in lens portions 312, 3312. FIG.

As shown in FIG. 18, in the lens portions 312 and 3312 of the modified example, a composite surface structure of the diffusion surfaces 313 and 3313 and the virtual base surface Sb may be formed on the front incident surface 310 (this figure shows the diffusion surface 313 example). In this case, the virtual base surface Sb on which the diffusion surfaces 313 and 3313 similar to those in the first embodiment are synthesized may have a planar shape substantially perpendicular to the optical axis Al. Further, in this case, the front exit surface 311 of the lens portions 312 and 3312 may have a convex shape that curves smoothly in any direction including the Xb direction and the Yb direction.

In the image display panel 21 of the modified example, the pixel regions 212 may be one-dimensionally arranged in one row in one of the Xa direction and the Ya direction. In the front lens array 31 of the modified example, the front lens portions 312 may be one-dimensionally arranged in one row in one of the Xb direction and the Yb direction. In the rear lens array 32 of the modified example, the rear lens portions 322 may be one-dimensionally arranged in one row in one of the Xc direction and the Yc direction. In a modification, the light source units 402 may be one-dimensionally arranged in one row in one of the Xd direction and the Yd direction.

The Xa direction and the Ya direction in the image display panel 21 of the modified example may be exchanged with each other. The Xc direction and the Yc direction in the rear-stage lens array 32 of the modified example may be exchanged with each other. The Yd direction in each of the light source units 402, 2402, 3402 of the modified example may correspond to the horizontal direction Dh of the virtual image VRI (see FIG. 1 of the first embodiment).

3 translucent member 20 image forming unit 30 condensing unit 40 lighting unit 100 HUD 212 pixel area 312, 3312 front lens section 313, 3313 diffusion surface 322 rear lens section 323, 325 regular refracting surface section , 324, 326 reverse refraction surface, 327 connection surface, 328, 329 boundary, 402 light source, Dv vertical direction, VRI virtual image, θ angle space

Claims (7)

A virtual image display device (100) for visibly displaying a virtual image (VRI) of the display light by reflecting the display light with a translucent member (3),
a lighting unit (40) that emits white illumination light;
an image forming unit (20) that forms an image by transmission of the illumination light and emits the display light of the image;
a light collecting unit (30) for collecting the illumination light toward the image forming unit;
The image forming unit has a plurality of pixel regions (212) arranged,
The condensing unit is
A plurality of diffusing surfaces (313, 3313) for diffusing the illumination light within a range within an angular space (θ) for condensing the illumination light incident on each pixel region. arrayed front-stage lens units (312, 3312);
Refracting surface portions (323, 325) condensing by refraction the illumination light in the angle space , which is individually incident on each pixel region, are arranged at a right angle to the optical axis (Al) at the rear stage of each of the front lens portions. A virtual image display device having a plurality of rear lens sections (322) arranged so as to be intermittently formed in directions (Xc, Yc). 2. The virtual image display device according to claim 1, wherein said diffusing surface (313) presents a wavefront shape in which waves travel in a direction (Yb) along said orthogonal direction (Yc). 2. The virtual image display device according to claim 1, wherein the diffusion surface (3313) presents a wave surface shape in which waves travel in directions (Xb, Yb) along the pair of orthogonal directions (Xc, Yc) that are orthogonal to each other. . 4. The virtual image display device according to claim 3, wherein the waves have different maximum amplitudes (Ax, Axi, Ay, Ayi) in the directions (Xb, Yb) in which the waves travel along the pair of orthogonal directions that are orthogonal to each other. . The virtual image display device according to any one of claims 2 to 4, wherein the orthogonal direction includes a direction corresponding to the vertical direction (Dv) of the virtual image. The rear-stage lens section includes forward refracting surface portions (323, 325) as the refracting surface portions that collimate the illumination light by refraction, and to mix the illumination light collimated by the forward refracting surface portion , The virtual image display device according to any one of claims 1 to 5, wherein the reverse refracting surface portions (324, 326) for refracting the illumination light are alternately formed in the orthogonal direction (Xc, Yc). The illumination unit has a plurality of light source sections (402) arranged so as to emit the illumination light individually incident on each set of the front lens section and the rear lens section. The virtual image display device according to any one of the items.