WO2019151498A1

WO2019151498A1 - Display member and display device

Info

Publication number: WO2019151498A1
Application number: PCT/JP2019/003700
Authority: WO
Inventors: 野村英司; 山田範秀; 橋村淳司
Original assignee: コニカミノルタ株式会社
Priority date: 2018-02-01
Filing date: 2019-02-01
Publication date: 2019-08-08
Also published as: JPWO2019151498A1

Abstract

Provided is a display member 100 to be disposed on a windshield 8, the display member 100 comprising a first optical element 111 and a second optical element 112, wherein a second Fresnel shape portion 112a has a shape obtained by substantially inverting the shape of a first Fresnel shape portion 111a, the first and second optical elements 111 and 112 are bonded so that the first and second Fresnel shape portions 111a and 112a are opposed to each other. On a bonding surface CR, display light HK from an image forming element 30 is polarized and reflected by at least one of the first and second Fresnel shape portions 111a and 112a as reflected light, and light from the opposite side of the image forming element 30 is transmitted as transmitted light, so that the reflected light and the transmitted light can be observed while being superposed on each other. A first groove 1a extends while being inclined with respect to a vertical direction orthogonal to a horizontal direction.

Description

Display member and display device

The present invention relates to a display member used for projecting and displaying an image while having light transparency, and a display device for displaying an image by projection.

A light transmissive screen (or display member) is used for a display device such as a head-up display (hereinafter referred to as HUD) device. This screen reflects display light from the optical unit or drawing unit of the display device and transmits light from the outside. In the HUD device, display light enters the screen from an oblique direction with the observer's head as the front. Therefore, the display light is required to be bent in a predetermined direction corresponding to the front surface so that the observer can recognize a projection image by the display light on the screen.

Some windshields include a combination of a line and a blank portion between an external glass plate and an internal glass plate, and have a pattern portion that reflects an incident image using the line (see Patent Document 1). In the windshield of Patent Document 1, a PVB film is provided between the pattern portion and the internal glass plate. The line of the pattern part reflects all or part of the display light of the HUD device, and the blank part is formed between the lines and transmits light. The pattern portion is composed of a combination of discontinuous or continuous horizontal, vertical, or curved lines, a lattice line, or a combination of a circular, elliptical, polygonal, or fuzzy line. Such a configuration of the pattern portion solves the problem of the double image generated in the windshield.

However, Patent Document 1 does not disclose deflecting the direction of display light in a predetermined direction.

Further, in the windshield, an optical device comprising an optical member comprising a Fresnel-shaped portion in which a plurality of grooves are formed on one surface in the thickness direction, and a half mirror layer formed on the surface of the Fresnel-shaped portion. (See Patent Documents 2 and 3). In particular, in the optical device of Patent Document 2, the plurality of grooves in the Fresnel-shaped portion have free curved surfaces on their surfaces. Moreover, the depth of each groove | channel and the angle of a reflective surface are changed. In addition, the distance from the central portion of the Fresnel-shaped portion to each point on the circumference can be changed for each circumferential position of each groove. The optical device of Patent Document 2 can have a free-form surface characteristic by continuously changing the angle of the reflecting surface of each groove according to the difference in the circumferential position along the groove. The three-dimensional distortion which exists in the etc. is suppressed.

However, in the optical device of Patent Document 2, the Fresnel shape of a free-form surface is described as described above, but when the groove pitch is constant in a specific direction, if the shape having a large curvature change is Fresneled, the groove ring The belt height increases. Therefore, when such an optical device is applied to a windshield, thickness becomes a problem. Furthermore, the light beam that passes through the vicinity of the step of the Fresnel structure is shielded, and a missing portion is generated in the virtual image, which may result in a virtual image with poor image quality.

Further, the windshield includes first to third optical layers, the first optical layer and the second optical layer are in close contact with each other, and the first optical layer and the third optical layer are in contact with each other. Some have an optical member in close contact (see Patent Document 4). The first optical layer has a concave portion on the first main surface and a plurality of convex ridge portions provided around the concave portion, and has a convex portion on the second main surface facing the first main surface. A plurality of protrusions provided around the protrusion. The refractive index of the first optical layer is higher than the refractive index of the second optical layer and higher than the refractive index of the third optical layer. The optical member of Patent Document 4 suppresses distortion of the external image that passes through the windshield while enlarging the display image.

Some windshields include an optical sheet having a main surface provided with a Fresnel lens, and an optical element in which the optical axis of the Fresnel lens is arranged at a position different from the center of the outer shape of the main surface. (See Patent Document 5). In Patent Document 5, a transparent plate such as a windshield that supports an optical element is disposed on the main surface side.

The optical members and optical elements of Patent Documents 4 and 5 have a Fresnel shape, but the Fresnel shape is axisymmetric in the region including the optical member and the optical element, has no free-form surface, and has an astigmatic difference. Can occur. Thereby, performance degradation of an observation image (projection image) arises.

JP 2012-51780 A JP 2016-180871 A Japanese Patent Laying-Open No. 2015-161732 JP 2010-78860 A JP 2011-191715 A

The present invention has been made in view of the above-described background art, and an object thereof is to provide a display member that can reduce the size of a device that generates display light while ensuring a wide viewing angle and a wide eyebox. And

Another object of the present invention is to provide a display device capable of projecting a virtual image while ensuring image display performance.

In order to achieve at least one of the above objects, a display member reflecting one aspect of the present invention is provided on a display screen, and has a first Fresnel having a plurality of first grooves on one surface. A first optical element having a shape portion, and a second optical element having a second Fresnel shape portion having a plurality of second grooves on one surface, wherein the second Fresnel shape portion is a portion of the first Fresnel shape portion. The first optical element and the second optical element are joined in a state where the first Fresnel shape part and the second Fresnel shape part are opposed to each other. At the joint surface of the two optical elements, the display light from the image forming element is reflected while being deflected as reflected light by at least one of the first and second Fresnel-shaped portions, and light from the opposite side of the image forming element is reflected. Transmit as transmitted light It makes the observable overlapping the reflected light and transmitted light, the first groove extending obliquely relative to the longitudinal direction orthogonal to the horizontal direction. Note that the substantially inverted shape also means that the shape of the second Fresnel shape portion is not completely the same as the shape of the first Fresnel shape portion inverted, and may include some errors. In this case, it is desirable that an adhesive or the like be interposed between the first and second Fresnel shaped portions.

In order to achieve at least one of the above objects, a display device reflecting one aspect of the present invention includes a display image including the display member, a display screen provided with the display member, and a virtual image displayed over the display member. And a drawing unit for displaying an image corresponding to.

In order to achieve at least one of the above objects, a display device reflecting one aspect of the present invention is a virtual image projection optical system that displays an image formed by an image forming element by projecting a virtual image through a display screen. The virtual image projection optical system includes at least one Fresnel element, and includes a vibration mechanism that finely vibrates at least one member constituting the virtual image projection optical system.

1A and 1B are diagrams illustrating a display member and a display device incorporating the display member according to the first embodiment. 2A is a longitudinal sectional view for explaining the configuration of the display member and the display device shown in FIG. 1A, and FIG. 2B is a partial transverse sectional view of the display member. 3A is a plan view of the display member of FIG. 2A as viewed from the first optical element side, FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A, and FIG. 3C is the display member of FIG. FIG. FIG. 4A is a diagram illustrating the groove structure of the display member and reflection on the reflection surface, and FIG. 4B is a diagram illustrating a non-reflective region of the display member. It is a figure explaining the display member etc. which concern on 2nd Embodiment. It is a figure explaining the display member etc. which concern on 3rd Embodiment. It is a figure explaining the modification of a display member. It is a figure explaining another modification of a display member. It is a figure explaining another modification of a display member. It is an expanded side sectional view explaining the specific structural example of the display apparatus of 4th Embodiment. 11A is a front view of the Fresnel element in the virtual image projection optical system incorporated in the display device, and FIG. 11B is an enlarged cross-sectional view taken along the line A-A ′ of the Fresnel element in FIG. 11A. It is a block diagram explaining the display system for moving bodies containing a display apparatus. It is a perspective view explaining the concrete display state. 14A is an example of the fourth embodiment, and is a YZ cross-sectional view of an optical arrangement when a Fresnel element is used as a mirror, and FIG. 14B is an XZ cross-sectional view of the optical arrangement of FIG. 14A. 15A is a comparative example of the fourth embodiment, and is a YZ sectional view of an optical arrangement when a mirror is used in the virtual image generating optical system, and FIG. 15B is an XZ sectional view of the optical arrangement of FIG. 15A. . It is an expansion side sectional view explaining the example of concrete composition of the display of a 5th embodiment. FIG. 17A is a plan view for explaining a Fresnel element in the virtual image projection optical system, and FIG. 17B is an enlarged cross-sectional view of the Fresnel element in FIG. FIG. 18A is a front view illustrating the display device according to the sixth embodiment from the vehicle inner side, and FIG. 18B is a side cross-sectional view illustrating the display device. It is a figure explaining a Fresnel element among the display apparatuses of 7th Embodiment. It is an expanded side sectional view explaining the example of a concrete structure of the display apparatus of 8th Embodiment. FIGS. 21A and 21B are a partially broken plan view and a partially broken side view for explaining the structure of the diffusion part incorporating the intermediate screen, and FIG. 21C is a view for explaining the movement of the functional area accompanying the rotation of the intermediate screen. It is. It is a front view explaining the modification of a Fresnel element.

[First Embodiment]
Hereinafter, a display member and a display device according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1A, 1B, 2A, and 2B, the display member 100 of the present embodiment is embedded in a light-transmitting plate member such as a windshield 8 or a windshield of a moving body such as an automobile. ing. In the present embodiment, the display unit 130 that is a part of the windshield 8 functions as a display screen, and the display member 100 is incorporated in the display screen. The windshield 8 is formed by bonding a first optical member 110 and a second optical member 120 made of glass. The display member 100 is a film-like sheet-like member 90, and the sheet-like member 90 is sandwiched between the first optical member 110 and the second optical member 120 constituting the windshield 8. Part of it.

The display member 100 has an internal transmittance of 80% or more in the visible light wavelength region. The display member 100 clearly projects a projection image (display light) from a drawing unit 210 of the display device 200 described later, and transmits light from the outside. That is, when the display member 100 is used for the display device 200 such as a HUD device, an observer (driver UN) or the like can observe an external background through the display member 100 and also can observe a projected image.

The display member 100 has a structure in which the first optical element 111 and the second optical element 112 are joined. The display member 100 is provided with a first optical member 110 on a surface (specifically, a flat surface 111b) opposite to the bonding surface CR of the first optical element 111, and the bonding surface CR of the second optical element 112. The second optical member 120 is provided on the opposite surface (specifically, the flat surface 112b). Thereby, the whole shape of the display member 100 can be made to follow the shape of the windshield 8, and handling of the display member 100 can be made easy. Moreover, the maintenance of the display member 100 can be simplified. The first and second

optical elements

111 and 112 are curved according to the shape of the windshield 8 having a display screen. When the windshield 8 has a curved surface, the

flat surfaces

111b and 112b also have a curved surface instead of a perfect plane. The elemental reflecting surface constituting the display member 100 is premised on the change in angle due to this curvature.

The first optical element 111 of the display member 100 is disposed on the driver UN side as an observer, and has a first Fresnel-shaped portion 111a having a plurality of first grooves 1a on one surface. The second optical element 112 has a second Fresnel-shaped portion 112a that is disposed on the opposite side of the driver UN facing the first optical element 111 and has a plurality of second grooves 2a on one surface. That is, the first and

second grooves

1a and 2a are two-dimensionally arranged on the surfaces of the first and second optical elements 111 and 112 (see FIG. 3A). The second Fresnel shape portion 112a has a shape that is substantially the reverse of the shape of the first Fresnel shape portion 111a. The substantially inverted shape also means that the shape of the second Fresnel shape portion 112a is not completely the same as the shape obtained by inverting the shape of the first Fresnel shape portion 111a, and may include some errors. To do. The 1st optical element 111 and the 2nd optical element 112 are joined by the joint surface CR in the state which made the 1st Fresnel shape part 111a and the 2nd Fresnel shape part 112a oppose. In this case, it is desirable that an adhesive or the like be interposed between the first and second Fresnel-shaped

portions

111a and 112a. Although details will be described later, in the bonding surface CR, the first optical element 111 and the second optical element 112 have substantially the same refractive index. In this case, distortion of the transmitted light that passes through the display member 100 can be prevented. In the first and second

optical elements

111 and 112, the surfaces opposite to the bonding surface CR are

flat surfaces

111b and 112b, respectively. The display member 100 causes display light HK from an image forming element 30 to be described later on the bonding surface CR of the first and second

optical elements

111 and 112 by at least one of the first and second

Fresnel shape portions

111a and 112a. The reflected light is reflected while being deflected, and the light from the side opposite to the image forming element 30 is transmitted as transmitted light, so that the reflected light and the transmitted light can be superposed and observed. Here, the deflection of the display light HK by the Fresnel-shaped

portions

111a and 112a means that the display member 100 is not specularly reflected in the overall shape of the display member 100, that is, the incident angle and the reflection angle do not exactly match, When the reference axis is considered for the entire surface of the display member 100 or an approximate surface such as an aspheric surface approximated to the curved surfaces of the

flat surfaces

111b and 112b, the optical axis as the fine shape of the Fresnel-shaped

portions

111a and 112a is used as the reference axis. This means that a mismatch occurs without matching. Specifically, the deflection of the display light HK by the Fresnel-shaped

portions

111a and 112a is an angular difference in which the direction of the optical axis and the direction of the reference axis rotate around the X axis when observed in the YZ plane, for example. This means that when observed in the XZ plane, there is an angular difference in which the direction of the optical axis and the direction of the reference axis rotate about the Y axis. For example, when the Fresnel-shaped

portions

111a and 112a are formed by dividing a free-form surface and providing a step between the respective divided regions, the optical axis direction of the Fresnel-shaped

portions

111a and 112a is at the center of the

optical elements

111 and 112. What is necessary is just to be an approximate optical axis direction.

Any one of the surfaces of the first and second Fresnel-shaped

portions

111a and 112a is a mirror MR having desired reflection characteristics. In the display member 100, a large number of mirrors MR are gathered in the sheet-like member 90 to form a reflective surface 191 that extends in a planar shape along the windshield 8 as a whole. The reflectivity of the mirror MR is, for example, 15% to 30%. The mirror MR is made of metal, a multilayer film, or the like. The shapes of the first and second Fresnel-shaped

portions

111a and 112a are such that the inclination angle of the effective region of the mirror MR is a macroscopic incident angle θ1 to the sheet-like member 90 and a macroscopic exit angle θ2 from the sheet-like member 90. The display light HK from the drawing unit 210 is deflected and directed to the eye box. The mirror MR includes a first element MRa that contributes to reflection and a second element MRb that does not contribute to reflection. In order to realize a macroscopic exit angle θ2 with respect to the macroscopic incident angle θ1, one of the first elements Only MRa will be used. The second element MRb can be subjected to an antireflection treatment.

As shown in FIGS. 3A to 3C, in the first Fresnel-shaped portion 111a, the first groove 1a extends while being inclined with respect to the vertical direction orthogonal to the horizontal direction. In other words, the first groove 1a has a first direction α corresponding to the horizontal direction and a second direction β corresponding to the vertical direction orthogonal to the first direction α in the display unit 130 that is the region having the display member 100. Each is non-axisymmetric. Here, in the display member 100, the horizontal direction is based on the installation surface of the vehicle body 2. The vertical direction is not limited to the vertical direction, that is, the Y direction, but means a direction along a plane or curved surface in which the entire display member 100 extends. The first direction α is a direction in which the surface of the first optical element 111 and the XZ plane intersect. The second direction β is a direction in which the surface of the first optical element 111 and the YZ surface intersect. Here, the −Z direction is the forward direction of the vehicle body 2, and the X direction is the lateral direction of the vehicle body 2.

The plurality of first grooves 1a have a composite annular zone shape along the surface of the first optical element 111, and are arranged non-concentrically. Here, the non-concentric circle means that the radius of curvature along the display portion 130 of the arc local portion constituting each annular zone of the first groove 1a is the same arc or the radius of curvature of another arc local portion in the annular zone. Does not match. The composite ring zone shape is designed with reference to the maximum vertex of each first groove 1a. In this case, the complex annular zone shape of the first groove 1a has an aspheric shape (including a toric surface) or a free-form surface shape characterized by asymmetry such as non-axisymmetric or eccentricity, and is free of Fresnel shape. The degree can be increased and the optical magnification can be increased. Thereby, the visual field of the virtual image can be widened, and the display device 200 can be downsized. The center of curvature along the composite ring-shaped display unit 130 is in a position that is obliquely shifted with respect to the center of the display unit 130 of the display member 100, and the display light HK can be obliquely deflected by the Fresnel-shaped unit 111a. I have to. Therefore, the center of the image forming element 30 to be described later is not disposed at a regular reflection position corresponding to, for example, the YZ plane passing through the center of the display unit 130 or in the vicinity of the center, and the curvature of the complex annular zone shape of the first groove 1a. It is arranged in a diagonally downward direction shifted to the center side. With such a configuration, the degree of freedom of arrangement of the image forming element 30 is increased, and for example, there is an advantage that the apparatus can be arranged without interference with a member below the display member 100 such as a handle. It can be said.

The heights h1 and h2 of the first groove 1a are constant in the cross section in the first direction α corresponding to the horizontal direction and the cross section in the second direction β corresponding to the horizontal direction. Here, the heights h1 and h2 of the first grooves mean the difference between the maximum vertex and the minimum vertex in each first groove 1a. In this case, the horizontal direction or the vertical direction in the vehicle body 2 may be used as a reference, but the first direction α and the second direction β pass through the center of the image and are determined based on chief rays entering the eye box. Can do. Thereby, it becomes easy to make the thickness of the display member 100 substantially constant, and the incorporation into the windshield 8 provided with the display screen can be facilitated.

Each surface of the plurality of first grooves 1a has either an aspherical shape or a free curved surface shape. As a result, not only a high-resolution virtual image can be displayed, but also the bonding surface CR in the display member 100 has a refractive power, so that it is easy to maintain the image quality and the light enters from the display device 200 in which the display member 100 is incorporated. The luminous flux can be made relatively small. Thereby, the optical system of the display device 200 can be reduced, and the display device 200 can be downsized. The curvature of the surface of the first groove 1a varies depending on the position in at least one of the first and second directions α and β. Thereby, even when the heights h1 and h2 of the first groove 1a are constant, the state can be ensured when the reflected light is deflected and reflected by the display member 100 in a predetermined direction.

It is desirable that the pitches p1 and p2 of the first groove 1a change according to the position in at least one of the first and second directions α and β. Thereby, even if the heights h1 and h2 of the first groove 1a are constant, the reflected light can be deflected and reflected in a predetermined direction on the display member 100.

Also, it is desirable that the angle with respect to the direction perpendicular to the thickness direction of the surface of the first groove 1a also changes depending on the position in at least one of the first and second directions α and β. Thereby, even if the heights h1 and h2 of the first groove 1a are constant, the reflected light can be deflected and reflected in a predetermined direction on the display member 100.

As described above, the first Fresnel-shaped portion 111a has a structure in which the first groove 1a of the first Fresnel-shaped portion 111a is inclined with respect to the second direction β, which is the vertical direction orthogonal to the horizontal direction. So that the principal ray at the center of the incident light beam from the light beam and the principal ray at the center of the emitted light beam reflected by the reflecting surface 91 of the display member 100 and guided to the pupil HT of the driver UN pass in a predetermined direction or in a predetermined plane. Is set to As a result, the first Fresnel-shaped portion 111a can correct or adjust the change in the reflection angle (that is, the emission angle θ2) with respect to the incident angle (that is, the incident angle θ1) of the display light HK on the display member 100. A desired deflection can be realized. The shape of the first Fresnel-shaped part 111a is based on the inclination of the first groove 1a with respect to the vertical direction, and corrects the light reflection angle and deflects the reflected light in a side sectional view in the first and second directions α and β. However, the astigmatic difference is set to be corrected. By determining the shape parameters of the first direction α component and the second direction β component in the first groove 1a, the inclination angle with respect to the vertical direction of the first groove 1a is determined, and the extending direction of the first groove 1a is determined. The incident angle to the reflecting surface 91 can be set in the entire range from 0 ° to 90 °, for example, depending on the structure of the first Fresnel-shaped portion 111a.

In the first Fresnel-shaped portion 111a, the heights h1 and h2, the pitches p1 and p2, and the curvature and the like of the first groove 1a are necessary for ensuring performance in combination with the optical system constituting the HUD device. The value is determined from the structure. Note that the second Fresnel shape portion 112a has a shape that is substantially inverted from the first Fresnel shape portion 111a, and therefore description of dimensions and the like is omitted (the same applies hereinafter).

As shown in FIG. 4A, the angle formed by the first element MRa and the second element MRb of the mirror MR, that is, the Fresnel surface angle b, is a surface 100a corresponding to the incident surface of the display member 100 of the incident light beam (in this embodiment, , The direction (or angle, that is, incident angle θ1) with respect to the surface of the first optical member 110, the direction (or angle, that is, emission angle θ2) with respect to the surface 100a corresponding to the incident surface of the display member 100, and the display member. 100 is determined by the refractive index of the medium constituting 100. The luminous flux from the light source placed at a certain distance with respect to the display member 100 is, for example, when the luminous flux is incident as diverging light, depending on the position of incidence on the incident surface of the display member 100. The incident angle of the light beam at the position (that is, the incident angle θ1) changes.

As shown in FIG. 4B, the display member 100 may generate a non-reflective area DA that does not contribute to the reflection because the display light L1 does not enter the first Fresnel-shaped portion 111a. The first Fresnel-shaped portion 111a is preferably designed so that the non-reflection area DA is minimized. If the heights h1 and h2 of the first groove 1a and the pitches p1 and p2 are set to such an extent that diffraction does not become a problem, and the heights h1 and h2 of the first groove 1a are made as small as possible, the non-reflection area DA is reduced. Can do.

The display member 100 is manufactured by press molding, transfer molding using a photocurable resin, or the like. The first and second

optical elements

111 and 112 are made of a light-transmitting organic material or inorganic material. As already described, in the bonding surfaces CR of the first and second

optical elements

111 and 112, the base material on the first Fresnel shape portion 111a side and the base material on the second Fresnel shape portion 112a side have substantially the same refraction. Have a rate. Here, substantially the same refractive index means having a refractive index difference of about 0 to 0.05. In this case, it is possible to prevent problems such as refraction at the joint surface CR of the first and second

optical elements

111 and 112, and to prevent deterioration such as image distortion. The refractive indexes of the first and second

optical elements

111 and 112 are based on the refractive index of the base material having the first groove 1a on which the display light L1 is reflected (that is, the first Fresnel-shaped portion 111a). It is desirable.

Hereinafter, the usage state of the display member 100 will be described. As shown in FIGS. 1A, 1B, and 2A, the display member 100 is incorporated in the display device 200. The display device 200 is mounted in the vehicle body 2 as, for example, a head-up display (HUD) device, and includes a drawing unit 210 and a display member 100. The display device 200 displays image information displayed on the image forming element 30 described later on a virtual image or projects a virtual image through the display member 100. In the present embodiment, the display member 100 is installed integrally with the windshield (front window) 8.

The drawing unit 210 of the display device 200 is installed so as to be embedded in the dashboard 4 of the vehicle body 2, and displays the display light HK corresponding to an image including driving-related information, a danger signal, and the like on the display unit 130 of the display member 100. It injects towards. Here, the display unit 130 means a region having the display member 100 in the windshield 8. The display unit 130 functions as a display screen, and is a part that displays an image from the image forming element 30 in the windshield 8. The display unit 130 includes a first optical surface 11a provided on the observation side where the driver UN is present or the driver's seat 6 side, and a second optical surface 12a provided on the counter-observation side. The reflectance of the display unit 130 is higher than the reflectance of the area around the display unit 130. In this case, the display unit 130 can make an image easier to see than the periphery of the display unit 130. The area of the display unit 130 and the surrounding area are determined by the viewing angle of the observer (driver UN) and the specifications of the eye box. The display unit 130 reflects the display light HK from the drawing unit 210 toward the rear of the vehicle body 2. The display light HK reflected by the display member 100 (display unit 130) is guided to the eye box corresponding to the pupil HT of the driver UN and its peripheral position. The driver UN can observe the display light HK reflected by the display member 100, that is, the display image IM as a virtual image in front of the vehicle body 2. On the other hand, the driver UN can observe external light transmitted through the display member 100, that is, a real image such as a front scene. As a result, the driver UN overlaps the external image behind the display unit 130, and displays a display image (virtual image) IM including operation-related information and the like formed by reflection of the display light HK on the display unit 130 of the display member 100. Can be observed.

2A and 2B, the drawing unit 210 includes an image forming unit 40 including an image forming element 30, an enlarged projection optical system 50, and a housing 14. Note that FIG. 2A and the like illustrate the configuration of the display device 200, and the configuration of the display device 200 is appropriately changed depending on the specification, installation location, and the like.

Although not described in detail, the image forming unit 40 includes, in addition to the image forming element 30, a display driving circuit that causes the image forming element 30 to perform a display operation, and an LED that emits light for illuminating the image forming element 30. Other light sources, a uniformizing optical system for uniformizing light from such light sources, and the like are provided. The image forming element 30 may be a reflective element such as a digital mirror device (DMD) or a reflective liquid crystal element (LCOS), or a transmissive element such as a liquid crystal display (for example, a liquid crystal display (LCD)). In particular, when a DMD is used for the image forming element 30, images can be switched at high speed while maintaining brightness, which is advantageous for display.

The enlarged projection optical system 50 includes a first projection optical system 51 that forms an intermediate image corresponding to the image formed on the image forming element 30 and an image light corresponding to the intermediate image that is incident on the display member 100 to generate a virtual image. And a second projection optical system 52 for displaying. The magnifying projection optical system 50 has the intermediate screen 16 at or near the position where the intermediate image is formed. Although detailed description is omitted, the intermediate screen 16 can be a movable member that moves in the direction of the optical axis AX. In this case, the enlarged projection optical system 50 has a variable focus, and can change the projection distance of the display image (virtual image) IM.

The housing 14 has an opening 14a through which the display light HK passes, and a film-like or thin plate-like light transmission member 14b can be disposed in the opening 14a.

As shown in FIG. 1A, the display light HK reflected by the display member 100 is guided to the pupil HT of the driver UN. Here, the virtual image light beam KK obtained by extending the display light HK behind the display member 100 forms a display image (virtual image) IM at a predetermined position ahead of the driver's pupil HT. The distance from the pupil HT to the display member 100 is about 0.5 to 1 m, for example, depending on the specifications of the vehicle body 2, and the distance from the display member 100 to the display image IM is about 1 m or more, for example. The viewing angle is about −10 ° to −15 °. The eye box is set so as to cover the position of the pupil HT of a standard driver UN, and is set to a size of, for example, 10 to 15 cm in width and 5 to 8 cm in length.

The first optical surface 11a (actually, the bonding surface CR) disposed on the pupil HT side of the display member 100 displays an image formed on the image forming element 30 via the enlarged projection optical system 50 with respect to the pupil HT. The display image IM is displayed or projected with little distortion. At this time, the first optical surface 11a can form a display image IM without distortion depending on the shape of the optical surface. In the case where the antireflection film is not provided on the second optical surface 12a, or when some reflection remains in the antireflection film, the display light branched through the first optical surface 11a also in the second optical surface 12a. HK is partially reflected. In this case, the display light reflected on the second optical surface 12a behind the branch after branching (hereinafter referred to as sub display light for convenience) passes through the first optical surface 11a and enters the pupil HT, so that the display image IM To form a double image. However, if the secondary display light reflected by the second optical surface 12a travels from the same point on the display image IM in relation to the original display light HK, the virtual image and the secondary display by the display light HK are displayed. Formation of a double image can be avoided by overlapping with a virtual image by light. In order to control the traveling direction of the sub display light, the curvature or inclination angle of the second optical surface 12a and the thickness of the base material may be adjusted with reference to the first optical surface 11a.

In the display member 100 described above, the viewing angle and the eye box can be sufficiently ensured by deflecting the reflected light to be incident on the driver UN side on the joint surface CR in the display member 100. Further, the deflection can provide a degree of freedom in the arrangement of the display device 200 such as a HUD device. Further, the first groove 1a constituting the first Fresnel-shaped portion 111a extends at an angle with respect to the vertical direction (specifically, the second direction β) orthogonal to the horizontal direction, so that the first groove 1a is orthogonal. The display device 200 incorporating the display member 100 can be reduced in size, for example, the size of an optical member such as the second projection optical system 52, and the entire display device 200 can be downsized. Can be achieved.

[Second Embodiment]
Hereinafter, the display member etc. which concern on 2nd Embodiment are demonstrated. The display member of the second embodiment is a modification of the display member of the first embodiment, and items that are not particularly described are the same as those of the first embodiment.

As shown in FIG. 5, in the present embodiment, the display member 100 is provided in a combiner 108 that is a member independent of the windshield 8. That is, the combiner 108 has a display screen function. In this case, the arrangement of the display member 100 can be changed as appropriate.

[Third Embodiment]
Hereinafter, the display member etc. which concern on 3rd Embodiment are demonstrated. The display member of the third embodiment is a modification of the display member of the first embodiment, and items that are not particularly described are the same as those of the first embodiment.

As shown in FIG. 6, in this embodiment, the windshield 8 is disposed so as to extend in a substantially vertical direction. Accordingly, the display member 100 or the display unit 130 provided in the windshield 8 is also arranged to extend in a substantially vertical direction. Since the display unit 130 includes desired Fresnel-shaped

portions

111a and 112a, the display member 100 is displayed to the observer (driver UN), and a HUD device in a moving body in which a front window such as a truck or a bus is close to the ground. Even when the display device 200 such as the above is arranged on the windshield 8, the observer (driver UN) can sufficiently observe the image projected at the oblique incidence while observing the image of the outside world. At that time, while ensuring the performance of the reflected image displayed on the display device 200 such as a HUD device, the transmitted image outside the vehicle is not distorted. That is, in the display member 100 in a substantially vertical state, for example, an image projected from obliquely below or obliquely above the display member 100 to the display member 100 by the Fresnel-shaped

portions

111a and 112a of the display member 100. The reflected image can be returned in a predetermined direction. Thereby, even in a moving body in which front windows such as buses and trucks are arranged substantially vertically, a windshield type display device 200 using the front window as a display member 100 is achieved, and space can be used effectively.

The first to third embodiments described above are merely examples. For example, as shown in FIG. 7, the sheet-like member 90 composed of the first and second

optical elements

111 and 112 has a wedge shape whose thickness changes. You may have. In this case, it is possible to prevent a double image generated due to a deviation between the transmitted light transmitted through the display member 100 and the reflected light reflected by the display member 100.

In the first to third embodiments, the composite annular zone shape along the surface of the first optical element 111 of the first groove 1a is an example, and can be appropriately changed according to the specification. For example, as shown in FIG. 8, the composite annular zone shape along the surface of the first optical element 111 of the first groove 1a is not limited to the shape inclined in an arc shape, but may be a shape inclined in a linear shape. Good.

In the first to third embodiments, the vertex connecting the first element MRa and the second element MRb of the mirror MR may have an R plane. Thereby, it is possible to prevent the display light L1 from being scattered near the apex. In addition, the R surface should just be provided in the vertex into which the display light L1 injects, ie, the Z side.

In the first to third embodiments, a sheet-like member 90 as the display member 100 may be attached to the windshield 8 as shown in FIG. The sheet-like member 90 is affixed to the windshield 8 or the like via an adhesive or an adhesive layer.

In the first to third embodiments, the surface opposite to the bonding surface CR of the first optical element 111 and the bonding surface CR of the second optical element 112 are related to the optical system of the display device 200. Can be configured to give power such as curvature to the opposite surface.

In the first to third embodiments, the example in which the display member 100 (or the sheet-like member 90) is manufactured by separately molding the first and second

optical elements

111 and 112 and giving them is described. After the first optical element 111 is molded, the second optical element 112 is molded in a state where the first optical element 111 is inserted into the mold for the second optical element 112 to manufacture the display member 100 (or the sheet-like member 90). May be.

In the first to third embodiments, the drawing unit 210 and the like shown in FIG. 2A and the like are merely examples, and the configuration of the magnifying projection optical system 50 is changed as appropriate, or the image forming element 30 is changed to another type of image formation. It can be replaced with an element. For example, the enlarged projection optical system 50 can be changed to a fixed focus optical system. In the drawing unit 210, for example, a configuration in which the enlarged projection optical system 50 is omitted or a configuration in which the first projection optical system 51 is omitted may be employed.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of a display device according to the present invention will be described with reference to the drawings.

As shown in FIG. 10, the display member 20 is a half mirror also called a combiner, and is a concave mirror or a plane mirror having semi-transparency. The display member 20 is erected on the dashboard 4 by supporting the lower end, and reflects the display light HK from the drawing unit 210 toward the rear of the vehicle body 2. That is, in the illustrated case, the display member 20 is an independent type installed separately from the windshield (wind shield) 8. The display light HK reflected by the display member 20 that is a half mirror is guided to an eye box (not shown) corresponding to the pupil HT of the driver (driver) UN sitting in the driver's seat 6 and its peripheral position. The driver UN can observe the display light HK reflected by the display member 20, that is, the display image IM as a virtual image in front of the vehicle body 2. On the other hand, the driver UN can observe external light transmitted through the semi-transmissive display member 20, that is, a real image of a front scene, a car, and the like. As a result, the driver UN superimposes the external image behind the display member 20 and displays a display image (virtual image) IM including driving-related information and a danger signal formed by reflection of the display light HK on the display member 20. Can be observed.

In the above, the display member 20 may correspond to the driver UN side optical surface of the windshield 8. Further, the display member 20 is not limited to a concave mirror or a plane mirror, and may be a curved surface such as an aspheric surface, may be a further curved surface, or may be a free curved surface having no symmetry.

The drawing unit 210 includes a main body optical system 13, a display control unit 18 that operates the main body optical system 13, and a housing 14 that houses the main body optical system 13 and the like. Among these, the combination of the main body optical system 13 and the display member (combiner) 20 constitutes a virtual image projection optical system (or virtual image display optical system) 1030. In FIG. 10 and the like, the coordinate axes XYZ have the origin at the center of the eye box corresponding to the position between the pupils HT of a general driver UN, but are displayed with the origin shifted for convenience.

Although details will be described later, the virtual image projection optical system 1030 includes at least one Fresnel element 1050. Further, the virtual image projection optical system 1030 includes a vibration mechanism 80 that finely vibrates at least one member constituting the virtual image projection optical system 1030. It should be noted that an appropriate member that complements the missing portion generated in the virtual image according to the configuration of the virtual image projection optical system 1030 is finely vibrated. In the present embodiment, an example in which the first mirror 17a constituting the second projection optical system 52 described later is a Fresnel element 1050 is given, and the Fresnel element 1050 is finely oscillated.

The main body optical system 13 includes an image forming element 30, a first projection optical system 51 capable of forming an intermediate image TI obtained by enlarging an image formed on the image forming element 30, and an image forming position of the intermediate image TI. An intermediate screen 16 disposed downstream of the optical path and a second projection optical system 52 that converts the intermediate image TI into a virtual image are provided. The image forming element 30 is also called a display device or a drawing device. Although details will be described later, the virtual image projection distance is variable by the main body optical system 13 functioning as a virtual image projection optical system. The first projection optical system 51, the intermediate screen 16, and the second projection optical system 52 are an enlarged projection optical system 50 that enlarges the image of the image forming element 30. The enlarged projection optical system 50 can make the FOV of the virtual image wider in the display device 200 while securing the eye box.

The image forming element 30 is a display unit having a two-dimensional display surface 30a. The image formed on the display surface 30a of the image forming element 30 is enlarged by the first projection optical system 51 in the main body optical system 13 to form the intermediate image TI, passes through the intermediate screen 16, and passes through the second projection optical system. 52 etc. At this time, by using the image forming element 30 capable of two-dimensional display, the intermediate image TI or the display image (virtual image) IM can be switched at a relatively high speed. Although not shown, in addition to a display panel such as a liquid crystal display panel (or a liquid crystal display (LCD)) attached to the image forming element 30, a display driving circuit for causing the liquid crystal display panel to perform a display operation, An LED or other light source that emits light for illuminating the liquid crystal display panel, a uniformizing optical system that uniformizes light from the light source, and the like are provided. By using a liquid crystal display as the display panel, the apparatus can be downsized. Further, since the light distribution angle of the LCD is wide, the FOV of the virtual image can be widened. Note that the image forming element 30 operates at a frame rate of, for example, 60 fps or more. This makes it easy to make it appear as if a plurality of display images IM are simultaneously displayed at different projection distances.

The image forming element 30 can change the luminance pattern in accordance with the region or pattern shielded by the Fresnel structure 1051 constituting the Fresnel element 1050 described later. That is, the brightness of the display unit of the image forming element 30 is partially changed.

The first projection optical system (imaging optical system) 51 is a fixed-focus lens system, and has a plurality of lens elements (not shown). The first projection optical system 51 is disposed closer to the image forming element 30 than the intermediate screen 16. The F value of the first projection optical system 51 is 2.0 or more. The first projection optical system 51 magnifies and projects an image formed on the display surface 30a of the image forming element 30 to an appropriate magnification, and the intermediate image TI (or the incident surface 19m) is positioned near the incident surface 19m of the intermediate screen 16. To form a forced intermediate image TI ′). Here, the forced intermediate image TI ′ includes not only the intermediate image TI itself but also an image that is slightly out of focus by being displaced from the intermediate image TI. The first projection optical system 51 has a stop 15a arranged closest to the intermediate screen 16 of the first projection optical system 51. As described above, by arranging the stop 15a, setting and adjustment of the F value on the intermediate screen 16 side of the first projection optical system 51 are relatively easy. Note that the aperture of the first projection optical system 51 may be disposed anywhere in the lens system.

The intermediate screen 16 is a member whose diffusion angle is controlled to a desired angle, and forms a forced intermediate image TI 'at an image formation position (that is, an image formation planned position of the intermediate image TI or its vicinity). As a result, by moving the intermediate screen 16 in the optical axis AX direction as will be described later, the position of the forced intermediate image TI ′ can also be moved in the optical axis AX direction. For the intermediate screen 16, for example, a diffusion plate, a diffusion screen, a microlens array, or the like can be used. The eye box size can be enlarged by the intermediate screen 16. The intermediate image TI is formed in a display area from the intermediate screen 16 to the front stage of the optical path. The incident surface 19m of the intermediate screen 16 has a diffusion function. A forced intermediate image TI 'is formed on the incident surface 19m, and light diffuses therefrom, so that a wide eye box can be secured. The intermediate screen 16 moves within the depth of focus of the first projection optical system 51.

The intermediate screen 16 is driven by the arrangement changing device 62 and moves along the optical axis AX, for example, at a constant speed or a periodic movement. That is, the position of the intermediate screen 16 is variable. In the case of this example, the optical axis AX passes through the center of the image forming element 30, the center of the eye box, and the image point (virtual image) corresponding to the center of the image forming element 30 created by the display device 200. is there. A display image IM as a virtual image formed behind the display member (combiner) 20 functioning as a display screen by the second projection optical system 52 by moving the intermediate screen 16 along the optical axis AX by the arrangement changing device 62. And the driver UN who is the observer can be lengthened or shortened. In other words, the arrangement changing device 62 changes the configuration distance of the main body optical system 13 or the virtual image projection optical system 1030 to change the projection distance. In this way, the position of the projected display image IM is changed back and forth, and the display content is made to correspond to the position, so that the display image IM is changed while changing the virtual image distance or the projection distance to the display image IM. The display image IM as a series of projection images can be made three-dimensional. The range of movement of the intermediate screen 16 along the optical axis AX corresponds to the image formation planned position of the intermediate image TI or the vicinity thereof, but is within the range of the focal depth of the first projection optical system 51 on the intermediate screen 16 side. Is desirable. As a result, the forced intermediate image TI ′ and the imaging state of the display image IM as a virtual image can both be brought into a good state that is substantially in focus. The amount of movement of the intermediate screen 16 in the optical axis AX direction is, for example, 20 mm or less. Thereby, the movement of the intermediate screen 16 can be performed efficiently, and the responsiveness of the intermediate screen 16 can be improved. The moving speed of the intermediate screen 16 is preferably a speed at which the display image IM as a virtual image can be displayed as if it is displayed at a plurality of locations or a plurality of virtual image distances simultaneously. The arrangement changing device 62 moves the intermediate screen 16 at a speed of, for example, 15 Hz or more. In this case, since the speed exceeds the perception of the observer (driver UN), the observer can recognize virtual images with different projection distances almost simultaneously.

The intermediate screen 16 is supported by the support member 62a. The support member 62a is attached to the base 62b of the arrangement changing device 62 so as to be movable within a predetermined range along the optical axis AX direction. At the timing when the intermediate screen 16 is arranged on the most upstream side of the movement range (that is, the side closest to the first projection optical system 51), the image displayed on the intermediate screen 16 at this time is a display that is a half mirror. It is displayed as a virtual image farthest behind the member (display screen or combiner) 20. Further, at the timing when the intermediate screen 16 is arranged on the most downstream side of the movement range (that is, the side farthest from the first projection optical system 51), the image displayed on the intermediate screen 16 at this time is a half mirror. It is displayed as a virtual image closest to the back of a certain display member (combiner) 20.

The virtual image generation optical system (second projection optical system) 52 is an enlargement optical system that expands the intermediate image TI formed in the vicinity of the intermediate screen 16 in cooperation with the display member 20, and as a virtual image in front of the driver UN. The display image IM is formed. The second projection optical system 52 is disposed on the virtual image side with respect to the intermediate screen 16. The second projection optical system 52 has a reflection optical system and is composed of at least one mirror. In the illustrated example, the second projection optical system 52 includes two first and

second mirrors

17a and 17b. Here, the first mirror 17a is a first reflector and is disposed on the image forming element 30 side in the preceding stage of the optical path, and has optical power. The second mirror 17b is disposed on the display member (combiner) 20 side in the latter stage of the optical path and has optical power. The first and

second mirrors

17a and 17b can be convex surfaces, concave surfaces, or flat surfaces. In the case of curved surfaces, the first and

second mirrors

17a and 17b are not limited to spherical surfaces but can be aspherical surfaces, free curved surfaces, or the like.

11A and 11B, the first mirror 17a of the second projection optical system 52 is a Fresnel element (Fresnel mirror) 1050. The Fresnel element 1050 has a Fresnel structure 1051 in which arc-shaped jagged projections are repeatedly formed in one direction at a predetermined pitch P1, and has a mirror coat layer on the surface of the Fresnel structure 1051. Although the pitch P1 is constant here, it is not necessarily constant. As shown in FIG. 11A, the Fresnel structure 1051 constituting the Fresnel element 1050 has a non-concentric pattern. Further, as shown in FIG. 11B, the surface 1051a of the Fresnel structure 1051 has a free-form surface. In the non-concentric circular shape, the radius of curvature of the local arc portion does not coincide with each other in the same arc. In this case, the optical magnification can be increased by increasing the degree of freedom of the shape of the Fresnel element 1050, the FOV of the virtual image can be widened, and the display device 200 can be made compact.

In this embodiment, the vibration mechanism 80 vibrates the first mirror 17a which is the Fresnel element 1050. As the vibration mechanism 80, for example, a piezo element or the like is used.

As shown in FIG. 11A, the vibration direction CD of the fine vibration is set within an angle range of ± 30 ° with respect to the direction perpendicular to the tangent L1 of the Fresnel structure 1051 at the center of the Fresnel element 1050. In this case, the vibration direction CD based on the Fresnel pattern becomes one-dimensional, and the control of fine vibration can be simplified. The stroke of fine vibration is shorter than the average pitch of the Fresnel structure 1051 constituting the Fresnel element 1050. Specifically, for example, the average pitch of the Fresnel structure 1051 is 0.3 mm to 0.6 mm, which is about half of that. The tangent line L1 is preferably based on an average of the tangent lines of each pattern of the Fresnel structure 1051.

Referring back to FIG. 10, the housing 14 has an opening 14a through which the display light HK passes, and a film or a thin plate-like light transmission member 14b can be disposed in the opening 14a.

FIG. 12 is a block diagram illustrating the mobile display system 300, and the mobile display system 300 includes the display device 200 as a part thereof. The display device 200 has the structure shown in FIG. 10, and a description thereof is omitted here. A moving body display system 300 shown in FIG. 12 is incorporated in an automobile or the like that is a moving body.

The mobile display system 300 includes a driver detection unit 71, an environment monitoring unit 72, and a main control device 1090 in addition to the display device 200.

The driver detection unit 71 is a part that detects the presence of the driver UN and the viewpoint position, and includes a driver seat camera 71a, a driver seat image processing unit 71b, and a driver seat image determination unit 71c. The driver's seat camera 71a is installed in front of the driver's seat of the dashboard 4 in the vehicle body 2 (see FIG. 1B), and takes an image of the head of the driver UN and its surroundings. The driver seat image processing unit 71b performs various types of image processing such as brightness correction on the image captured by the driver seat camera 71a to facilitate processing in the driver seat image determination unit 71c. The driver seat image determination unit 71c detects the head and eyes of the driver UN by extracting or cutting out an object from the driver seat image that has passed through the driver seat image processing unit 71b, and the depth associated with the driver seat image. The spatial position of the driver UN's eyes (and consequently the direction of the line of sight) is calculated along with the presence / absence of the driver's UN head in the vehicle body 2 from the information.

The environment monitoring unit 72 is a part for identifying a car, a bicycle, a pedestrian, and the like that are close to the front, and includes an external camera 72a, an external image processing unit 72b, and an external image determination unit 72c. The external camera 72a is installed at appropriate locations inside and outside the vehicle body 2 and captures external images of the driver UN or the windshield 8 such as the front and sides. The external image processing unit 72b performs various types of image processing such as brightness correction on the image captured by the external camera 72a to facilitate processing by the external image determination unit 72c. The external image determination unit 72c extracts or cuts out an object from the external image that has passed through the external image processing unit 72b, thereby determining whether a target such as a car, a bicycle, or a pedestrian (for example, the object OB shown in FIG. 13) exists. While detecting, the spatial position of the target object in front of the vehicle body 2 is calculated from the depth information accompanying the external image.

The driver's seat camera 71a and the external camera 72a are not shown, but are, for example, compound eye type three-dimensional cameras. That is, both

cameras

71a and 72a are obtained by arranging camera elements, each of which includes an imaging lens and a CMOS or other image sensor, in a matrix, and each has a drive circuit for the image sensor. The plurality of camera elements constituting each of the

cameras

71a and 72a are adapted to focus at different positions in the depth direction, for example, or to detect relative parallax, and are obtained from each camera element. By analyzing the state of the image (focus state, object position, etc.), the distance to each region or object in the image can be determined.

Even if a combination of a two-dimensional camera and an infrared distance sensor is used instead of the compound-

eye cameras

71a and 72a as described above, the depth direction of each part (area or object) in the captured screen is used. Distance information can be obtained. In addition, distance information in the depth direction can be obtained for each part (region or object) in the captured screen by using a stereo camera in which two two-dimensional cameras are separately arranged in place of the compound-

eye cameras

71a and 72a. In addition, in a single two-dimensional camera, distance information in the depth direction can be obtained for each part in the captured screen by performing imaging while changing the focal length at high speed.

The display control unit 18 operates the virtual image projection optical system 1030 under the control of the main controller 1090 to display a three-dimensional display image IM in which the virtual image distance or the projection distance changes behind the display member 20. The display control unit 18 generates a display image IM to be displayed on the virtual image projection optical system 1030 from display information including the display shape and display distance received from the environment monitoring unit 72 via the main control device 1090. The display image IM is, for example, a display frame (see display frame HW shown in FIG. 13) located in the periphery with respect to the direction of the depth position with respect to an automobile, a bicycle, a pedestrian, or other object existing behind the display member 20. Can be a good sign.

In displaying the display image IM, in the image forming element 30 of the virtual image projection optical system 1030, the luminance pattern is changed according to the area shielded by the Fresnel structure 1051 constituting the Fresnel element 1050. The change in the luminance pattern may correspond to one edge of the Fresnel structure 1051 or may correspond to an average of a plurality of edges. By changing the in-plane luminance of the image forming element 30, the luminance of the entire virtual image is adjusted. Specifically, the brightness of the display area of the image forming element 30 passing through the area where the pitch of the Fresnel element 1050 is narrow is made higher than the brightness of the display area of the image forming element 30 passing through the area where the pitch of the Fresnel element 1050 is wide. Yes. This makes it possible to display a display image (virtual image) IM that is easier to recognize.

The display control unit 18 receives a detection output related to the presence of the driver UN and the eye position from the driver detection unit 71 via the main control device 1090. Thereby, the projection of the display image IM by the virtual image projection optical system 1030 can be automatically started and stopped. Further, the display image IM can be projected only in the direction of the line of sight of the driver UN. Further, it is possible to perform projection with emphasis such as brightening or blinking only the display image IM in the direction of the line of sight of the driver UN.

The main controller 1090 has a role of harmonizing the operations of the display device 200, the environment monitoring unit 72, and the like, and the virtual image projection optical system 1030 corresponds to the spatial position of the object detected by the environment monitoring unit 72. Adjust the spatial arrangement of the display frame and other images projected by.

FIG. 13 is a perspective view illustrating a specific display state. A detection area VF corresponding to the observation field is provided in front of the driver UN as an observer. It is assumed that objects OB1 and OB3 of a person such as a pedestrian and a moving object OB2 such as an automobile exist in the detection area VF, that is, in and around the road. In this case, main controller 1090 causes display device 200 to project a three-dimensional display image (virtual image) IM, and displays display frames HW1, HW2, and HW3 as related information images for objects OB1, OB2, and OB3. Append. At this time, since the distance from the driver UN to each object OB1, OB2, OB3 is different, the projection distance to the display images (projected images) IM1, IM2, IM3 for displaying the display frames HW1, HW2, HW3 is the driver This corresponds to the distance from the UN to each object OB1, OB2, OB3. Note that the projection distances of the display images IM1, IM2, and IM3 are discrete, and cannot be accurately matched to the actual distances to the objects OB1, OB2, and OB3. However, if the difference between the projected distances of the display images IM1, IM2, IM3 and the actual distance to the objects OB1, OB2, OB3 is not large, parallax hardly occurs even if the viewpoint of the driver UN moves, and the objects OB1, The positional relationship between OB2 and OB3 and the display frames HW1, HW2, and HW3 can be substantially maintained.

In the display device described above, the virtual image projection optical system 1030 includes at least one Fresnel element 1050, and the Fresnel element 1050 is finely oscillated to compensate for a missing portion generated in the display image (virtual image) IM. It is possible to display a display image (virtual image) IM with no missing part. Thus, the FOV of the virtual image is wide and the display device 200 can be made compact while maintaining the eye box, and an image that can be easily recognized by the display device 200 can be visually recognized by the observer (driver UN).

(Example)
Hereinafter, specific examples of the present embodiment will be described. As shown in FIGS. 14A and 14B, the second projection optical system 52 of this embodiment is composed of a single first mirror 17a and a windshield. In the present embodiment, the first mirror 17 a is a Fresnel element 1050. The first mirror 17a is a flat mirror when viewed macroscopically, but a Fresnel structure 1051 is formed on a surface on the image forming element 30 side which is a reflection surface.

15A and 15B show an optical arrangement in the case where only the first mirror 17a that is not the Fresnel element 1050 is provided in the second projection optical system 52 as a comparative example. The first mirror 17a of the comparative example has a concave surface on the surface on the image forming element 30 side. As can be seen from FIGS. 14A, 14B, 15A, and 15B, even if the first mirror 17a is the Fresnel element 1050, it can be the same as the conventional optical arrangement. However, in the embodiment, the display device 200 can be made smaller by using the first mirror 17a as the Fresnel element 1050. In the display device incorporating the optical system of the embodiment shown in FIG. 14A and the like, the missing portion generated in the virtual image can be complemented by finely vibrating the first mirror 17a which is the Fresnel element 1050. It is possible to display a virtual image having no missing part as compared with the configuration.

[Fifth Embodiment]
The display device according to the fifth embodiment will be described below. The display device according to the fifth embodiment is a modification of the display device according to the fourth embodiment, and items not particularly described are the same as those in the fourth embodiment.

As shown in FIG. 16, in the present embodiment, the display member 20 is a Fresnel element 1050. As shown in FIG. 16, when the display member (display screen) 20 is a combiner, the Fresnel element 1050 can be finely vibrated using the vibration mechanism 80.

As shown in FIGS. 17A and 17B, the display member 20 is a Fresnel element (Fresnel screen) 1050. In FIG. 17A, the Fresnel structure 1051 draws a concentric arc-shaped pattern. In the concentric pattern, the radius of curvature of the arc local portion is the same in each arc local portion in the same arc. Further, the concentric pattern includes an off-axis type in which the center of the concentric circle is not included in the Fresnel element 1050. In this case, mold processing for producing the Fresnel element 1050 with the off-axis optical system becomes easy. As shown in FIG. 17B, the Fresnel element 1050 is composed of two base materials 1053. The Fresnel structure 1051 is provided on one surface of each base material 1053, and they face each other. The Fresnel element 1050 has a half mirror coat layer 1052 on the Fresnel structure 1051. There may be a medium having substantially the same refractive index between the half mirror coat layer 1052 and the base material 1053 on the opposite side. In that case, the one base material 1053 which does not have the half mirror coat layer 1052 may be a flat surface. As a result, the half mirror coat layer 1052 is sandwiched between a pair of base materials 1053 having substantially the same refractive index. Thereby, not only a virtual image can be visually recognized, but also external light transmitted through the Fresnel element 1050, that is, a real image of a front scene, an automobile, etc., can be visually recognized as a transmission image without distortion. Note that the base material 1053 including the Fresnel structure 1051 may be formed into a sheet shape and separately attached to the surface of the display member 20.

The Fresnel element 1050 has the same structure as the sheet-like member 90 (that is, the display member 100) shown in FIG. 2A and the like. Of the Fresnel element 1050, the two opposing base materials 1053 correspond to the

optical elements

111 and 112, and the half mirror coat layer 1052 corresponds to the mirror MR. The Fresnel-shaped portion 190 is formed by the three-dimensional shape of the half mirror coat layer 1052. Although details are omitted, the three-dimensional shape of the Fresnel-shaped portion 190 or the half mirror coat layer 1052 is similar to the three-dimensional shape of the Fresnel-shaped

portions

111a and 112a or the mirror MR with respect to the vertical direction orthogonal to the horizontal direction. It is inclined and extends.

[Sixth Embodiment]
The display device according to the sixth embodiment will be described below. The display device according to the sixth embodiment is a modification of the display device according to the fourth embodiment, and items not particularly described are the same as those in the fourth embodiment.

18A and 18B, in this embodiment, the display member 20 is a Fresnel element 1050. In this embodiment, the combiner part 220 is affixed as the display member 20 inside the rectangular reflection region 8d provided in front of the driver's seat of the windshield 8 forming the front window without providing a combiner. . The display member can be embedded in the windshield 8. Thus, when the display member 20 is provided on the windshield 8 of the car, members other than the Fresnel element 1050 among the members constituting the virtual image projection optical system 1030 are finely vibrated using the vibration mechanism 80. Specifically, for example, the image forming element 30, the lens constituting the first projection optical system 51, the mirror of the second projection optical system 52, and the like are finely vibrated. The vibration direction of the lens, mirror, or the like is a direction corresponding to a predetermined direction within an angular range of ± 30 ° with respect to a direction perpendicular to the tangent to the Fresnel structure 1051 at the center of the Fresnel element 1050, and is perpendicular to the optical axis AX, for example. It has become a direction.

[Seventh Embodiment]
The display device according to the seventh embodiment will be described below. The display device according to the seventh embodiment is a modification of the display device according to the fourth embodiment, and items not particularly described are the same as those in the fourth embodiment.

As shown in FIG. 19, in this embodiment, the vibration directions CD and EF of the fine vibration of the Fresnel element 1050 are ± 30 ° with respect to the direction perpendicular to the tangent L1 of the Fresnel structure 1051 at the center of the Fresnel element 1050. A predetermined direction within the range, and a direction perpendicular to the predetermined direction. In this case, the vibration directions CD and EF with the Fresnel pattern as a reference are two-dimensional, and a missing portion that can occur in a virtual image can be more accurately complemented. Vibrating in a two-dimensional vibration direction is particularly effective when the Fresnel structure 1051 has a pattern with a small radius of curvature. Similarly to the sixth embodiment, when a member other than the Fresnel element 1050 is vibrated finely, it can be vibrated in a two-dimensional direction.

[Eighth Embodiment]
The display device according to the eighth embodiment will be described below. The display device according to the eighth embodiment is a modification of the display device according to the fourth embodiment, and items not specifically described are the same as those in the fourth embodiment.

As shown in FIG. 20, in the present embodiment, the intermediate screen 16 constituting the virtual image projection optical system 1030 is provided in the diffusing unit 19. The diffusing unit 19 is disposed at a projection position or an imaging position by the imaging optical system (first projection optical system) 51 (that is, at or near the imaging position of the intermediate image), and the rotating body 19a and the hollow frame body 19b. And is driven around the reference axis SX at a constant speed, for example.

FIG. 21A is a front view illustrating the diffusing portion 19, and FIG. 21B is a side cross-sectional view illustrating the diffusing portion 19. The diffusing unit 19 includes a spiral rotating body 19a having an outline close to a disk as a whole, and a cylindrical hollow frame 19b that houses the rotating body 19a.

The rotating body 19a has a central portion 19c and an outer peripheral optical portion 19p. One surface 19f formed on the outer peripheral optical portion 19p of the rotating body 19a is formed as a smooth surface or an optical surface, and the intermediate screen 16 is formed over the entire surface on the surface 19f. The surface 19f of the rotating body 19a functions as the three-dimensional shape portion 116. The intermediate screen 16 is a diffusion plate whose light distribution angle is controlled to a desired angle, and has a diffusion degree (a diffusion angle of a half-value intensity of the diffusion distribution) of, for example, 20 ° or more. The intermediate screen 16 can be a sheet attached to the rotating body 19a, but may be a fine uneven pattern formed on the surface of the rotating body 19a. Further, the intermediate screen 16 may be formed so as to be embedded in the rotating body 19a. The intermediate screen 16 forms an intermediate image TI by diffusing the incident display light HK (see FIG. 20). The other surface 19s formed on the outer peripheral optical part 19p of the rotating body 19a is formed on a smooth surface or an optical surface. The rotator 19a is a light-transmitting spiral member, and the pair of

surfaces

19f and 19s is a spiral surface having the reference axis SX as a spiral axis. As a result, the intermediate screen 16 formed on one surface 19f is also formed along a continuous spiral surface. The rotating body 19a has substantially the same thickness t with respect to the reference axis SX or optical axis AX direction. The intermediate screen 16 is formed in a range corresponding to one period of the spiral. In other words, the intermediate screen 16 is formed in a range corresponding to one spiral pitch. As a result, a stepped portion 19j is formed at one place along the periphery of the diffusing portion 19.

In the rotating body 19a, one place along the circumferential direction is a functional area FA through which the optical axis AX of the main body optical system 13 passes, and an intermediate image TI is formed by a portion of the intermediate screen 16 in the functional area FA. The functional area FA moves at a constant speed on the rotating body 19a as the rotating body 19a rotates. That is, the display light (image light) HK is incident on the functional area FA that is a part of the rotating body 19a while rotating, so that the position of the functional area FA or the intermediate image TI reciprocates along the optical axis AX. (If the display of the image forming element 30 is not operating, an intermediate image as a display is not necessarily formed, but the position where the intermediate image will be formed is also called the position of the intermediate image). In the illustrated example, since the intermediate screen 16 is formed in a range corresponding to one cycle of the spiral, the functional area FA or the intermediate image TI of the intermediate screen 16 is stepped in the optical axis AX direction by one rotation of the rotating body 19a. It makes one round trip for a distance corresponding to.

The imaging optical system (first projection optical system) 51 has a predetermined focal depth that is equal to or greater than the moving range of the functional area FA so as not to be out of focus depending on the position of the intermediate screen 16 provided in the diffusing unit 19. .

The hollow frame body 19b has a cylindrical outer contour and includes a side surface portion 19e and a pair of

end surface portions

19g and 19h. The side surface portion 19e and the pair of

end surface portions

19g and 19h are formed of the same material having optical transparency. However, the side surface portion 19e may not have light transmittance. The

main surfaces

63a and 63b of the one end surface portion 19g can be, for example, smooth surfaces or optical surfaces that are parallel to each other, but can also be free-form surfaces or aspheric surfaces. Similarly, the

main surfaces

64a and 64b of the other end surface portion 19h can be, for example, smooth surfaces or optical surfaces that are parallel to each other, but can also be free-form surfaces or aspheric surfaces. The rotating body 19a in the hollow frame body 19b is fixed to the hollow frame body 19b via a pair of central shaft portions 65, and the hollow frame body 19b and the rotating body 19a rotate integrally around the reference axis SX. To do. In this way, by arranging the rotating body 19a provided with the intermediate screen 16 in the hollow frame body 19b, it is possible to suppress dust and the like from adhering to the rotating body 19a, and to generate sound accompanying the rotation of the rotating body 19a. Therefore, it is easy to stabilize the rotation of the rotating body 19a at a high speed. In addition, you may fix the rotary body 19a to the hollow frame 19b in the outer peripheral part.

Referring back to FIG. 20, the intermediate screen 16 (or the three-dimensionally shaped portion 116) of the rotating body 19a is lighted by rotating the diffusion portion 19 around the reference axis SX at a constant speed by the rotation driving portion 162 that is a screen driving portion. A position intersecting the axis AX (that is, the functional area FA) also moves in the direction of the optical axis AX. That is, for example, as shown in FIG. 21C, with the rotation of the rotating body 19a, the functional area FA on the intermediate screen 16 is sequentially shifted to the adjacent functional area FA ′ set at a position shifted at an equal angle, for example. , Move in the direction of the optical axis AX. By moving the functional area FA in the optical axis AX direction, the position of the intermediate image TI can also be moved in the optical axis AX direction. Although details will be described later, for example, the projection distance or the virtual image distance to the display image IM can be increased by moving the position of the intermediate image TI to the image forming element 30 side. Further, the projection distance or virtual image distance to the display image IM can be reduced by moving the position of the intermediate image TI to the second projection optical system 52 side.

The virtual image generation optical system (second projection optical system) 52 may have an optical characteristic that corrects the curvature of the intermediate screen 16 in the functional area FA of the rotator 19a (that is, the curvature of field of the intermediate image TI).

In the display device 200 shown in FIG. 20, by operating the rotation driving unit 162 under the control of the display control unit 18, the diffusion unit 19 rotates around the reference axis SX and the intermediate image TI corresponding to the functional area FA is displayed. The position repeatedly moves periodically in the direction of the optical axis AX, and the distance between the display image IM as a virtual image formed behind the display member 20 by the second projection optical system 52 and the driver UN as an observer is increased, Or it can be shortened.

[Deformation and others]
Although the display member etc. which concern on embodiment were demonstrated above, the display member etc. which concern on this invention are not restricted to said thing.

For example, in the first embodiment or the fourth embodiment, the display device 200 may be reversed upside down, and the display unit 130 or the display member 20 may be disposed above the windshield (front window) 8 or at the sun visor position. it can. In this case, the display unit 130 or the display member 20 is disposed obliquely downward and forward of the drawing unit 210. The display unit 130 or the display member 20 may be disposed at a position corresponding to a conventional mirror of an automobile.

Further, in the above-described embodiment, the outline of the display unit 130 or the display member 20 is not limited to a rectangle but can be various shapes.

The enlarged projection optical system 50 shown in FIG. 2 or the like, or the main body optical system 13 shown in FIG. 10 or the like is merely an example, and these optical configurations can be appropriately changed. For example, an intermediate image as a preceding stage of the intermediate image TI can be additionally formed in the first projection optical system 51. One or more mirrors having no optical power may be disposed in the optical path of the second projection optical system 52. In this case, it may be advantageous for downsizing the drawing unit 210 and the like by folding.

In the fourth embodiment and the like, the display position of the display image (virtual image) IM is not limited to the three locations exemplified in the above embodiment, and can be set to an appropriate number. The display of the display image IM can be set continuously or intermittently by changing the position. Further, the display position of the display image IM can be fixed without being changed.

In the fourth embodiment and the like, the LCD is used as the image forming element 30, but other types of display panels such as an organic EL may be used. In this case, the display device 200 can be reduced in weight. The image forming element 30 may be a reflective element such as DMD or LCOS. In particular, when a DMD is used as the image forming element 30, it is easy to switch images at high speed while maintaining brightness, which is advantageous for display in which a virtual image distance or a projection distance is changed. Further, the image forming element 30 can be replaced with a scanning type image element using MEMS instead of a reflection type element such as DMD.

In the fourth embodiment and the like, the pattern of the Fresnel structure 1051 may be either a concentric pattern or a non-concentric pattern. Further, the pattern of the Fresnel structure 1051 can be changed as appropriate according to the configuration of the virtual image projection optical system 1030. Specifically, as shown in FIG. 22, the center of the arc-shaped pattern of the Fresnel structure 1051 can be shifted in the horizontal direction.

In the fourth embodiment and the like, the first mirror 17a, the display member 20, and the like of the second projection optical system 52 are the Fresnel element 1050. However, a part of the lens constituting the first projection optical system 51 is a Fresnel element. It may be 1050. In this case, the Fresnel element 1050 is finely vibrated in a predetermined direction. Further, two or more Fresnel elements 1050 may be finely vibrated.

In the fourth embodiment and the like, the second projection optical system 52 is provided with one or two mirrors, but may be provided with three or more mirrors. In addition, as described above, when the display member 20, the lens, or the like is a Fresnel element, the mirror coat layer may be omitted. Further, the optical surface of a general mirror or Fresnel element type mirror constituting the display member 20 or other virtual image projection optical system 1030 is, for example, a symmetric aspherical surface or free-form surface, but is not limited thereto. A free-form surface having no symmetry may be used.

Further, in the fourth embodiment, similarly to the sixth embodiment, the display member 20 is disposed inside the rectangular reflection area provided in front of the driver's seat of the windshield 8 forming the front window without providing the combiner. A display screen may be formed by pasting. The display member 20 can also be embedded in the windshield 8. In this case, the portion of the windshield 8 in which the display member 20 is embedded becomes a display screen.

In the above embodiment, the first projection optical system 51 is a fixed focus optical system, but may be a variable focus optical system.

In the above embodiment, the intermediate screen 16 may not be provided.

In the above embodiment, the position of the projected display image IM is changed by moving the entire intermediate screen 16 along the optical axis AX or rotating around the reference axis SX. The position of the display image IM may be changed using another method such as sliding an intermediate screen having a partial region.

The display device 200 described above is not limited to a projection device mounted on an automobile or other moving body, but can be incorporated in a digital signage or the like, but can also be applied to other uses.

Claims

A display member provided on the display screen,
A first optical element having a first Fresnel-shaped portion having a plurality of first grooves on one surface;
A second optical element having a second Fresnel-shaped portion having a plurality of second grooves on one surface;
With
The second Fresnel shape part has a shape that is substantially the reverse of the shape of the first Fresnel shape part,
The first optical element and the second optical element are bonded in a state where the first Fresnel shape portion and the second Fresnel shape portion are opposed to each other,
The display light from the image forming element is reflected and deflected as reflected light by at least one of the first and second Fresnel-shaped portions on the joint surface of the first and second optical elements, and the image forming element By allowing the light from the opposite side to be transmitted as transmitted light, the reflected light and the transmitted light can be overlapped and observed,
The display member, wherein the first groove extends with an inclination with respect to a vertical direction perpendicular to the horizontal direction.
A first optical member constituting at least a part of the display screen is provided on a surface opposite to the bonding surface of the first optical element, and a surface opposite to the bonding surface of the second optical element is provided on the surface opposite to the bonding surface. The display member according to claim 1, wherein a second optical member constituting at least a part of the display screen is provided.
The display member according to claim 2, wherein the display screen is at least a part of a windshield.
The display member according to claim 2, wherein the display screen is a combiner.
The height of the first groove is constant in a cross section in the first direction corresponding to the horizontal direction and a cross section in the second direction corresponding to the vertical direction orthogonal to the first direction. The display member according to any one of the above.
The display member according to any one of claims 1 to 5, wherein a surface of the first groove has an aspherical shape or a free-form surface shape.
The curvature of the surface of the first groove varies depending on the position in at least one of a first direction corresponding to the horizontal direction and a second direction corresponding to the vertical direction orthogonal to the first direction. Item 7. The display member according to Item 6.
2. The pitch of the first grooves changes according to a position in at least one of a first direction corresponding to the horizontal direction and a second direction corresponding to the vertical direction orthogonal to the first direction. The display member according to any one of 1 to 7.
The angle of the surface of the first groove with respect to the direction perpendicular to the thickness direction is at least one of a first direction corresponding to the horizontal direction and a second direction corresponding to the longitudinal direction orthogonal to the first direction. The display member according to any one of claims 1 to 8, which changes depending on
The display member according to any one of claims 1 to 9, wherein the plurality of first grooves have a composite annular shape along a surface of the first optical element and are arranged in a non-concentric shape.
The display member according to any one of claims 1 to 10, wherein the first and second optical elements are curved according to an overall shape of the display screen.
A sheet-like member composed of the first and second optical elements;
The display member according to any one of claims 1 to 11, wherein the sheet-like member has a wedge shape whose thickness varies.
The display member according to any one of claims 1 to 12, wherein the first optical element and the second optical element have substantially the same refractive index at the bonding surface.
A display member according to any one of claims 1 to 13,
A display screen provided with the display member;
A drawing unit for displaying an image corresponding to a virtual image to be displayed through the display member;
A display device comprising:
A display device comprising a virtual image projection optical system for projecting a virtual image through a display screen and displaying an image formed by an image forming element,
The virtual image projection optical system includes at least one Fresnel element;
A display device comprising a vibration mechanism that finely vibrates at least one member constituting the virtual image projection optical system.
The display device according to claim 15, wherein the virtual image projection optical system includes an enlargement projection optical system that enlarges an image of the image forming element.
The enlargement projection optical system is disposed near an intermediate image forming position, a first projection optical system disposed closer to the image forming element than the intermediate screen, and disposed closer to the virtual image than the intermediate screen. The display device according to claim 16, further comprising a second projection optical system.
The display device according to any one of claims 15 and 16, wherein the image forming element is a liquid crystal display panel.
The display device according to any one of claims 15 to 18, wherein the Fresnel element is at least one of a mirror and a lens.
The display device according to any one of claims 15 to 18, wherein the Fresnel element is provided as at least a part of the display screen.
The display device according to claim 20, wherein the Fresnel element has a half mirror coat layer on a Fresnel structure, and the half mirror coat layer is sandwiched between a pair of base materials having substantially the same refractive index.
The display device according to any one of claims 15 to 21, wherein a stroke of the fine vibration is shorter than an average pitch of a Fresnel structure constituting the Fresnel element.
The display according to any one of claims 15 to 22, wherein the vibration direction of the fine vibration is set within an angle range of ± 30 ° with respect to a tangential perpendicular direction of the Fresnel structure at the center of the Fresnel element. apparatus.
16. The vibration direction of the fine vibration is a predetermined direction within an angle range of ± 30 ° with respect to a tangential vertical direction of the Fresnel structure at the center of the Fresnel element, and a direction perpendicular to the predetermined direction. The display device according to any one of items 1 to 22.
The display device according to any one of claims 15 to 19, and 22 to 24, wherein the vibration mechanism finely vibrates the Fresnel element.
The display device according to any one of claims 15 to 24, wherein the vibration mechanism finely vibrates a member other than the Fresnel element among members constituting the virtual image projection optical system.
The display device according to any one of claims 15 to 26, wherein the Fresnel structure forming the Fresnel element has a concentric pattern.
The display device according to any one of claims 15 to 26, wherein the Fresnel structure constituting the Fresnel element has a non-concentric circular pattern.
The display device according to claim 28, wherein a surface of the Fresnel structure constituting the Fresnel element has a free-form surface.
The display device according to any one of claims 15 to 29, wherein a luminance pattern of the image forming element is changed according to a region shielded by a Fresnel structure constituting the Fresnel element.
The Fresnel element is a display member provided on a display screen, and has a first optical element having a first Fresnel-shaped portion having a plurality of first grooves on one surface and a plurality of second grooves on one surface. A second optical element having a second Fresnel-shaped portion,
The display device according to any one of claims 15 to 29, wherein the first groove extends while being inclined with respect to a longitudinal direction orthogonal to the horizontal direction.