JP6930587B2 - Image display device - Google Patents

Description

The present invention relates to an image display device.

An image display device that emits light and displays an image so that an observer can see it is known. In Patent Document 1, a rotating body in which a filter for adjusting the amount of light or a color filter is installed in an opening is made rotatable around a predetermined rotation axis, and an image display for adjusting the amount and color of light passing through the opening is provided. The device is disclosed. In such a technique, the shape of the opening is a circle, a fan shape, or the like.

Japanese Unexamined Patent Publication No. 2005-70731

By the way, some image display devices emit image light having a rectangular cross section. Even in such an image display device, it is necessary to install a special filter or screen in the opening of the rotating body, rotate the rotating body according to the situation, and make the image light incident on the special filter or screen. I try to make various adjustments.

When rotating such a rotating body, in order to pass the image light emitted for a certain period of time, it is necessary to give the opening a shape corresponding to the movement locus of the cross section of the image light according to the rotation speed. Generally, the center line in the longitudinal direction of the rectangular cross section is directed toward the center of the rotating body or in the tangential direction of rotation. Often becomes. However, if the opening is fan-shaped after securing a sufficient area of the rectangular cross section, there is a problem that the diameter of the rotating body is increased and the image display device cannot be made compact.

The present invention has been made in view of the above problems, and is an image display device capable of reducing the diameter of a rotating plate while having an opening through which image light having a rectangular cross section having a relatively large area can pass. The purpose is to obtain.

An image display device that reflects one aspect of the present invention in order to achieve at least one of the above-mentioned objects.
A projection device that irradiates image light with a rectangular cross section,
A rotating plate having an opening through which the image light passes, and
It has a drive device for rotating the rotary plate around a rotation axis extending along the irradiation direction of the image light.
The opening has the shape of a locus in which the image light irradiated by the projection device moves relative to each other in response to the rotation of the rotating plate.
When viewed in the direction of the rotation axis, the projection device performs the image so that the longitudinal center line and the lateral center line in the rectangular cross section of the image light passing through the opening do not intersect the rotation axis. It emits light.

According to the present invention, it is possible to obtain an image display device capable of reducing the diameter of a rotating plate while having an opening through which image light having a rectangular cross section having a relatively large area can pass.

It is a schematic block diagram of the image display device 100 which concerns on this embodiment. It is sectional drawing of the rotation drive device 160. It is the figure which cut the structure of FIG. 2 along line III-III and looked at in the direction of an arrow. It is a figure which shows the state which the rotating plate 165A is relative rotating with the image light incident in the opening 165a. It is the same figure as FIG. 3 which concerns on a modification. It is the same figure as FIG. 3 which concerns on another modification. It is the same figure as FIG. 3 which shows the rotary plate RP1 of the comparative example 1. FIG. It is the same figure as FIG. 3 which shows the rotary plate RP2 of the comparative example 2.

The image display device according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image display device 100 according to this embodiment. The image display device 100 is mounted on a vehicle body (not shown) as, for example, a head-up display device, and includes a drawing unit 10 as a projection device and a display screen 20. The image display device 100 displays the image information displayed on the display element 11 described later in the drawing unit 10 so that the driver can visually recognize the virtual image via the display screen 20.

The drawing unit 10 of the image display device 100 is installed, for example, in the dashboard of a vehicle, and emits a display light HK corresponding to an image including driving-related information and the like toward the display screen 20. The display screen 20, also called a combiner, is a semitransparent concave mirror or a plane mirror. The display screen 20 is erected on the dashboard by the support of the lower end, and reflects the display light HK from the drawing unit 10 toward the rear of the vehicle (to the right in FIG. 1). That is, in the case of the illustration, the display screen 20 is a stand-alone type that is installed separately from the front window. Further, the display screen 20 may be omitted, and the function may be substituted by the front window.

The display light HK reflected by the display screen 20 is guided to an eye box (not shown) corresponding to the pupil HT of the driver sitting in the driver's seat and its peripheral position. The driver can observe the display light HK reflected by the display screen 20, that is, the display image IM as a virtual image in front of the vehicle. On the other hand, the driver can observe the outside light transmitted through the display screen 20, that is, the real image of the front view. As a result, the driver can observe the display image (virtual image) IM including the driving-related information and the like formed by the reflection of the display light HK on the display screen 20 on the external world image behind the display screen 20. can.

As shown in FIG. 1, the drawing unit 10 includes a main body optical system 13 which is a virtual image type magnifying image system including a display element 11, a display control unit 18 for operating the main body optical system 13 and a rotation drive device 160, and the like. A housing 14 for accommodating the main body optical system 13 and the like is provided. Of these, the combination of the main body optical system 13 and the display screen 20 constitutes the virtual image display optical system 30.

In addition to the display element 11, the main body optical system 13 includes a projection optical system 15 capable of forming an intermediate image TI that is an enlargement of the image formed on the display element 11, and the planned imaging position of the intermediate image TI or its vicinity (hereinafter,). The diffusion screen 16 placed at the imaging position (also referred to as the imaging position) and the image on the diffusion screen 16 (including the intermediate image TI itself and the one that is slightly out of focus due to the position shift from the intermediate image TI, are forced below. It is provided with a virtual image forming optical system 17 that converts a virtual image (referred to as an intermediate image) into a virtual image.

The display element 11 has a two-dimensional display surface 11a for displaying an image. The image formed on the display surface 11a is magnified by the projection optical system 15 of the main body optical system 13 and projected onto the diffusion screen 16 as image light having a rectangular cross section. Here, the rectangular cross section includes a rectangle or a square, and also includes a shape having at least one side curved and a shape having at least one of the four corners rounded.

At this time, by using the display element 11 capable of two-dimensional display, the switching of the projected image to the diffusion screen 16 can be performed at a relatively high speed. The display element 11 may be a reflective element such as a DMD or LCOS, or a transmissive element such as a liquid crystal display. In particular, when DMD is used as the display element 11, it becomes easy to switch images at high speed while maintaining brightness, which is advantageous for a display in which the virtual image distance or the projection distance is changed. The display element 11 operates at a frame rate of 30 fps or more. This makes it easy to make it appear that a plurality of display image (virtual image) IMs are displayed at the same time at different projection distances.

The projection optical system 15 is a fixed-focus lens system, and has a plurality of lenses (not shown). The projection optical system 15 magnifies and projects the image light corresponding to the image formed on the display surface 11a of the display element 11 on the diffusion screen 16 as a forced intermediate image at an appropriate magnification. The projection optical system 15 has an aperture (not shown) arranged closest to the diffusion screen 16 of the projection optical system 15. By arranging the diaphragm in this way, it becomes relatively easy to set and adjust the F number on the diffusion screen 16 side of the projection optical system 15.

The diffusion screen 16 is a diffusion plate for controlling the light distribution angle to a desired angle, and forms a forced intermediate image at an imaging position (that is, a planned imaging position of the intermediate image TI or its vicinity). As a result, by moving the diffusion screen 16 in the optical axis AX direction, the position of the forced intermediate image can also be moved in the optical axis AX direction. As the diffusion screen 16, for example, frosted glass, a lens diffusion plate, a microlens array, or the like can be used. The diffusion screen 16 is attached to the rotating plates 165A to 165F as described later, and is integrally rotated by the rotation driving device 160.

The virtual image forming optical system 17 magnifies the forced intermediate image formed on the diffusion screen 16 in cooperation with the display screen 20, and forms a display image IM as a virtual image in front of the driver. The virtual image forming optical system 17 is composed of at least one mirror, but includes two mirrors 17a and 17b in the illustrated example.

FIG. 2 is a cross-sectional view of the rotation driving device 160. The rotary drive device 160 transmits power between the case 161, the motor 162 fixed to the case 161, the rotary shaft 163 rotatably supported by the case 161 and the motor shaft 162a and the rotary shaft 163 of the motor 162. It has a gear train 164 for performing the above. Six rotating plates 165A to 165F are attached to the tip side of the rotating shaft 163 protruding from the case 161 at equal pitches P along the direction of the rotating axis RX so as to rotate integrally. It has become.

FIG. 3 is a view of the configuration of FIG. 2 cut along the line III-III and viewed in the direction of the arrow. In FIG. 3, for easy understanding, the rotating plate 165A and the cross section (that is, the intermediate image) TI of the image light incident on the diffusion screen 16 are shown separately. Here, it is assumed that the cross-sectional TI of the image light is rectangular in which the short side is a, the long side is b, and the diagonal length is c.

In the rotating plate 165A, six openings 165a to 165f having a common shape are arranged at equal angles point-symmetrically with respect to the rotating axis RX. Here, the respective openings do not have to be arranged at equal angles, and the optimum angle may be arbitrarily set according to the projection distance. Each of the openings 165a to 165f has a locus shape in which the irradiated image light moves relative to each other in accordance with the rotation of the rotating plate 165A. Taking the opening 165a as an example, the shape thereof will be specifically described. The opening 165a has an arc-shaped inner edge IE having a radius r1 and an arc-shaped outer edge OE having a radius r2 about the rotation axis RX. Further, the opening 165a connects the short side of the length a and the long side of the length b orthogonal to the short side of the length a at a position where the distance between one ends of the inner edge IE and the outer edge OE is c, and the inner edge IE At a position where the distance between the other ends of the outer edge OE is c, the long side of the length b and the short side of the length a orthogonal to the long side are connected.

The extending angle range between the inner edge IE and the outer edge OE is determined by the rotation speed of the rotating plate 165A and the irradiation time of the image light. Further, it is desirable that the radius r1 of the inner edge IE is a minimum value that does not cause interference between openings adjacent to each other in the circumferential direction. Further, it is desirable that the outer edge OE and the outer circumference 165 g of the rotating plate 165A are separated from each other by a constant distance Δ in order to secure the strength. The other openings 165b to 165f have the same shape.

The six rotating plates 165A to 165F each have six openings 165a to 165f, but the diffusion screen 16 is provided only in one of the openings, and the other openings have a space (transparent). It has become. In the rotating plate 165A of FIG. 3, the diffusion screen 16 shown by hatching is attached to the opening 165a with an adhesive or the like.

Similarly, although not shown, in the rotating plate 165B, the diffusion screen 16 is attached at an angular phase position corresponding to the opening 165b, and in the rotating plate 165C, the diffusion screen 16 is attached at an angular phase position corresponding to the opening 165c. In the rotating plate 165D, the diffusion screen 16 is attached at an angular phase position corresponding to the opening 165d, in the rotating plate 165E, the diffusion screen 16 is attached in an angular phase position corresponding to the opening 165e, and in the rotating plate 165F. , The diffusion screen 16 is attached at an angular phase position corresponding to the opening 165f, and all other openings are transparent. The opening to which the diffusion screen 16 is attached is referred to as a specific opening.

FIG. 4 is a diagram showing a state in which the rotating plate 165A is relatively rotated with the image light incident in the opening 165a. As is clear from FIG. 4, the longitudinal center line CL1 and the lateral center line CL2 of the rectangular cross-section TI of the image light do not pass through the rotation axis RX, respectively, and the points Q1 on the rotating plate 165A that rotates relative to each other. It is designed to pass through Q2.

In FIG. 2, the rotating plates 165A to 165F to which the diffusion screen 16 is attached are driven by the motor 162 together with the rotating shaft 163 and rotate at a constant angular velocity. Depending on the rotation position of the rotating plates 165A to 165F, the image light incident on the diffusion screen 16 of the rotating plate 165A passes through the openings of the other rotating plates arranged in the rotation axis RX direction. Similarly, the image light incident on the diffusion screen 16 of the rotating plates 165B to 165F passes through the openings of the other rotating plates arranged in the rotation axis RX direction. That is, the diffusion screen 16 passes through the diffusion screens 16 having different positions along the direction of the rotation axis RX according to the rotation positions of the rotary plates 165A to 165F, but the diffusion screen 16 accompanies the rotation of the rotary plates 165A to 165F. The images are sequentially arranged at the imaging position of the projection optical system 15 (at or near the planned imaging position of the intermediate image TI).

That is, due to the rotation of the rotating plates 165A to 165F, the six diffusion screens 16 sequentially move across the optical axis AX at different positions, and the diffusion screens 16 of the rotating plates 165A to 165F are placed on the optical axis AX in this order. Will be placed in. Specifically, when the diffusion screen 16 of the rotating plate 165A crosses the optical axis AX, it comes closest to the virtual image forming optical system 17, so that the image displayed on the display element 11 is behind the display screen 20. Appears as a virtual image closest to. On the other hand, when the diffusion screen 16 of the rotating plate 165F crosses the optical axis AX, it is most related to the virtual image forming optical system 17, so that the image displayed on the display element 11 is the farthest behind the display screen 20. Is displayed as a virtual image. Further, since the diffusion screens 16 of the rotating plates 165B to 165E are arranged between them, they are displayed as virtual images at the corresponding positions, so that the virtual image visually recognized by the driver changes in the depth direction like an animation. It will be. Furthermore, if the rotation speed of the rotating plate is increased and the rotating plate is rotated at 30 Hz or higher, preferably 60 Hz or higher, these multiple virtual images are observed at the same time and can be viewed as a three-dimensional image including the depth direction. It will be possible. When the rotating plates 165A to 165F make one rotation, the imaginary image returns to its original position. That is, in the present embodiment, the position of the virtual image can be changed in 6 steps in the depth direction.

By fixing the position of the virtual image while the rotating plates 165A to 165F rotate at a certain speed, the visibility of the driver is improved. Therefore, the openings 165a to 165f have a shape corresponding to the movement locus of the cross-sectional shape of the image light as shown in FIGS. 3 and 4.

According to this embodiment, the diffusion screen 16 can be moved along the optical axis AX. By moving the diffusion screen 16 along the optical axis AX, the distance between the observer and the display image IM as a virtual image formed behind the display screen 20 by the virtual image forming optical system 17 can be increased or decreased. .. In this way, by changing the position of the projected display image IM back and forth along the optical axis AX and making the display content according to the position, the virtual image distance to the display image IM is changed. The display image IM is changed, and the display image IM as a series of projected images can be made three-dimensional. Here, the moving range of the diffusion screen 16 along the optical axis AX corresponds to the planned imaging position of the intermediate image TI or its vicinity, but is the range of the depth of focus on the diffusion screen 16 side of the projection optical system 15. It is desirable to keep it inside. As a result, for example, even if a special mechanism such as a focusing means is not provided in the projection optical system, the state of the forced intermediate image and the imaging state of the display image IM as a virtual image are both in good focus. Can be in a state.

By providing the diffusion screen 16 in the above-mentioned main body optical system 13, not only can a forced intermediate image movable in the optical axis AX direction be formed, but also the light utilization of the optical system can be used while ensuring the viewing angle and the eyebox size. Efficiency can be increased. If the light distribution angle of the diffusion by the diffusion screen 16 is too narrow, the eyebox size becomes small. On the contrary, if the light distribution angle of the diffusion by the diffusion screen 16 is made too large, the F value of the virtual image forming optical system 17 needs to be reduced in order to increase the light utilization efficiency, so that the depth of focus becomes shallow and the display can be performed. The distance range is narrowed.

FIG. 5 is a diagram similar to FIG. 3 according to the modified example. In this modification, there are five rotating plates, one of which the rotating plate 165A'forms five openings 165a'to 165e', and the diffusion screen 16 is attached only to the openings 165a'. There is. Although not shown, four rotating plates other than the rotating plate 165A'have the same configuration. In this modification, the position of the virtual image can be changed in five steps in the depth direction. Other configurations are the same as those in the above-described embodiment.

FIG. 6 is a diagram similar to FIG. 3 according to the modified example. In this modification, there are four rotating plates, one of which the rotating plate 165A "forms four openings 165a" to 165d ", and the diffusion screen 16 is attached only to the openings 165a". There is. Although not shown, three rotating plates other than the rotating plate 165A "have the same configuration. In this modified example, the position of the virtual image can be changed in four stages in the depth direction. Other configurations are described above. It is the same as the said embodiment.

The results of the study by the present inventor will be described below. 7 and 8 are the same views as FIG. 3 showing the rotating plates RP1 and RP2 of the comparative example used in the study, and the cross-sectional TI of the image light passing through each opening is shown by the alternate long and short dash line. The rotating plate RP1 of FIG. 7 has six fan-shaped openings RP1a to RP1f, which are relative movement loci of the cross section TI of the image light. In the image light having a rectangular cross-section TI passing through the opening RP1a, the longitudinal center line L1 passes through the rotation axis RX, and the same applies to the other openings.

On the other hand, the rotating plate RP2 of FIG. 8 also has six fan-shaped openings RP2a to RP2f, which are relative movement loci of the cross section TI of the image light. In the image light having a rectangular cross-section TI passing through the opening RP2a, the center line L2 in the lateral direction passes through the rotation axis RX, and the same applies to the other openings.

Here, the short side of the rectangular cross-section TI of the image light is 31.19 mm, the long side is 83.17 mm, and the moving angle of the trajectory of the image light drawing one opening (extension of the inner edge IE or the outer edge OE in FIG. 3). The diameter of the rotating plate 165A shown in FIG. 3 as an example and the diameters of the rotating plates RP1 and RP2 as comparative examples were determined with ± 10 degrees as the current angle), and the following results were obtained.
(Example) Diameter of rotary plate 165A: 285 mm
(Comparative Example 1) Diameter of rotary plate RP1: 292 mm
(Comparative Example 2) Diameter of rotating plate RP2: 326.5 mm

According to the above examination results, the diameter of the rotating plate of the example was the smallest as compared with the comparative examples 1 and 2. According to this embodiment, it is possible to arrange a plurality of openings in the closest proximity to each other, and it is possible to reduce the size as compared with Comparative Examples 1 and 2, and the cross section of the image light passing through the openings. As long as the longitudinal center line or the lateral center line does not pass through the rotation axis, it can be set to any angle, so there is a degree of freedom in the placement position in the optical system, and the whole including other parts etc. The degree of freedom in designing is also expanded.

The present invention is not limited to the embodiments, modifications, and examples described in the present specification, and the inclusion of other embodiments and modifications includes the embodiments and examples described in the present specification. It is clear to those skilled in the art from the technical idea. The description and embodiments of the specification are for illustration purposes only, and the scope of the present invention is set forth by the claims described below. For example, the rotating plate and the opening may be provided with two, three, or seven or more. Further, not only the diffusion screen but also various elements such as a polarizing filter and a color filter can be arranged in the opening. Therefore, the present invention can be applied to other than the head-up display device.

10 Drawing unit 11 Display element 11a Display surface 13 Main body Optical system 14 Housing 15 Projection optical system 16 Diffusion screen 17 Virtual image formation optical system 17a, 17b Mirror 18 Display control unit 20 Display screen 30 Virtual image display optical system 100 Image display device 160 Rotational drive Device 161 Case 162 Motor 162a Motor shaft 163 Rotating shaft 164 Gear row 165A-165F, 165A'-165E', 165A "-165D" Rotating plate 165a-165f, 165a-165e, 165a "-165d" Opening L1 Longitudinal center Line L2 Short side center line RX Rotation axis TI intermediate image (cross section of image optics)

Claims (4)

A projection device that irradiates image light with a rectangular cross section,
A rotating plate having an opening through which the image light passes, and
It has a drive device for rotating the rotary plate around a rotation axis extending along the irradiation direction of the image light.
The opening has the shape of a locus in which the image light irradiated by the projection device moves relative to each other in response to the rotation of the rotating plate.
When viewed in the direction of the rotation axis, the projection device performs the image so that the longitudinal center line and the lateral center line in the rectangular cross section of the image light passing through the opening do not intersect the rotation axis. An image display device that emits light. The image display device according to claim 1, wherein a diffusion screen or a filter is attached to the opening. The image light passes through the openings in which N (N is an integer of 2 or more) of the rotating plates, each of which has N (N is an integer of 2 or more), are overlapped along the direction of the rotation axis. The diffusion screen or the filter is attached to a specific opening which is laminated and is one of the N openings, and the specific opening has a different rotation phase for each rotating plate. The image display device according to claim 2, which is arranged at a position. The image display device according to any one of claims 1 to 3, wherein the rectangular cross section is rectangular.

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