Patent Application
20240219717
The present invention relates to a display device, a virtual image display device, and a movable body.
Patent Document 1 discloses configurations of a display device, a virtual image display device, and a movable body of conventional art. Patent Document 1 discloses, for example, in paragraph 0026 and FIG. 7, etc., a virtual image display device as a head-up display (100) provided in a movable body (a vehicle). Particularly, the virtual image display device is provided with a display device as a liquid crystal display device (11).
In particular, the liquid crystal display device (11) is provided with a triangular prism (41, 42). Such a configuration in which a prism is provided on a display surface of a display device causes the structure to become more complicated as compared to a configuration in which no prism is provided, and thus, a manufacturing process is made complicated and the difficulty in manufacturing has been increased.
Hence, an object of the present invention is to provide, in light of the problem mentioned above, a display device with improved manufacturability even though the display device is provided with a prism, and also a virtual image display device and a movable body.
In order to achieve the above object, a display device according to the present invention is provided with: a display which includes a display surface that emits display light, and emits central display light in an emission direction that is non-perpendicular to the display surface; and a prism which is provided on the display surface, includes an incidence surface on which the display light is incident and an emitting surface which emits the display light, and has a thickness which is gradually increased in the emission direction, in which in the prism, a vertex of the emitting surface is positioned to be deviated from an immediately above region, which is located immediately above the incidence surface, toward the emission direction side.
In order to achieve the above object, a virtual image display device according to the present invention is provided with the display device described above, and displays a virtual image by projecting the display light onto a projection target member.
In order to achieve the above object, a movable body according to the present invention is provided with the virtual image display device described above, and further includes a windshield or a combiner as the projection target member.
A display device, a virtual image display device, and a movable body according to a first embodiment of the present disclosure will be described with reference to the drawings. As illustrated in
As illustrated in
As illustrated in
Characters include numbers, alphabets, hiragana, katakana, kanji, etc. Other than the above, the virtual image V1 may include an icon indicating a structural object standing on the ground, such as buildings or trees.
Next, a configuration of the head-up display device 100 will be described.
As illustrated in
Note that the display unit 20 and the prism 40 are also configured as an example of a display device D.
The case 30 is formed in a box shape by a light-shielding resin or metal. The concave mirror 12, the display unit 20, and the prism 40 are accommodated within the case 30. The case 30 includes a window portion 31 made of a light-transmissive member that transmits the display light L produced in the internal space of the case 30 toward the windshield 201.
The display unit 20 includes a display surface 21 which radiates the display light L representing an image. The display unit 20 may be of a type including a liquid crystal panel and an illumination device, or of a type including a reflective display element such as a digital micromirror device (DMD) element and a projector. The display surface 21 faces downward toward the front of the vehicle 200. Images displayed on the display surface 21 are subjected to distortion correction (warping) to correct a distortion of the virtual image V1 that is visually recognized by the viewer 1. The display surface 21 is inclined relative to an optical axis center La (i.e., a light beam connecting the center of the display surface 21 and the center of the visible region R, also referred to as central display light) of the display light L. The optical axis center La is positioned at the center of the transverse section of the beams of the display light L. Beams of the display light L and the optical axis center La are emitted in an emission direction which is non-perpendicular to the display surface 21.
The control portion 25 includes a central processing unit (CPU), a graphics display controller (GDC), a read-only memory (ROM), and a random-access memory (RAM), etc. The control portion 25 acquires information such as the vehicle speed and route guidance externally, and generates an image to be displayed on the display surface 21 on the basis of the aforementioned kinds of information.
The prism 40 is provided on the display surface 21, and the display light L emitted from the display surface 21 is transmitted therethrough. The prism 40 will be described in detail later.
As illustrated in
Next, a configuration of the prism 40 will be described. As illustrated in
As illustrated in
The virtual display plane 48A refers to an apparent position of the display surface 21, which is the original display plane. That is, while visual recognition of the display surface 21 is performed as the display light L which has passed through the prism 40 is perceived at the viewpoint EP, the visual recognition at this time is affected by the refractive index n of the prism 40. Therefore, it appears to the viewer as if the display surface 21 exists at the virtual display plane 48A. For example, in the present embodiment, the display surface 21 appears to exist at the virtual display plane 48A by the effect of the shape of the prism 40.
The prism 40 includes an incidence surface 41i, which is positioned to be opposed to the display surface 21 and on which display light from the display surface 21 is incident, and an emitting surface 41o, which is positioned on the opposite side of the incidence surface 41i and emits the incident display light L. The incidence surface 41i is formed in a rectangular plane shape. The incidence surface 41i of the prism 40 may be fixed to the display surface 21 by optical bonding, or the prism 40 may be supported by a support mechanism that is not illustrated.
The incidence surface 41i may be formed over the entire display surface 21. However, in the present embodiment, as illustrated in
The emitting surface 41o is formed in such a way that the thickness of the prism 40 is gradually increased in the emission direction of the display light L. The position of the virtual display plane 48A is determined according to how far the display light L has traveled from the incidence surface 41i to the emitting surface 41o. Specifically, in
As illustrated in
The vertex 41p corresponds to a place of the emitting surface 41o that is most distant in terms of the normal vector components of the incidence surface 41i. The vertex 41p is positioned to be deviated from an immediately above region Z, which is located immediately above the incidence surface 41i, toward the side in the emission direction of the display light L. It can also be said that the vertex 41p is positioned on the outer side of the immediately above region Z.
A display device provided with a prism forming the vertex 41p which is configured as described above can be easily manufactured. This is because, when a triangular prism as disclosed in Patent Document 1 described above is applied to the display device of the present embodiment, the prism is enlarged. Specifically, in a conventional prism (e.g., a triangular prism or the like), the prism is formed from a vertex portion to a surface along a perpendicular line drawn downward in the direction of an incidence surface, and this surface and the incidence surface form a right angle. Therefore, when the vertex 41p exists at a position deviated from a perpendicular region of the incidence surface 41i, as in the present embodiment, the prism is unnecessarily enlarged. Meanwhile, if the prism is configured like the prism 40 of the present disclosure, it is possible to prevent unnecessary enlargement of the prism toward the outer side from the incidence surface. Thus, as a result of reduction in the manufacturing cost and improvement of the handling properties, it is possible to improve manufacturability.
The prism 40 includes the protruding portion 42. The protruding portion 42 is a portion which is further projected toward the outer side of the prism 40 (i.e., the emission direction side) with respect to a virtual side surface 41v, which connects the vertex 41p and an end portion 41e of the incidence surface 41i. The virtual side surface 41v may be a surface formed downward from the vertex 41p toward the incidence surface 41i along a surface which is substantially parallel to the display light L.
A surface 42c is a surface formed adjacent to the vertex 41p as the outer shape of the protruding portion 42. For example, the surface 42c is formed in a direction of opening greatly toward the lower outer side from the vertex 41p as a starting point. The surface 42c is also adjacent to the emitting surface 41o, whereby a vertex angle θ1 is formed between the surface 42c and the emitting surface 41o. The vertex angle θ1 is formed to be more obtuse than a virtual angle θ2 formed at the vertex 41p when there is no protruding portion 42. The virtual angle θ2 is formed by the emitting surface 41o and the virtual side surface 41v, specifically. In the prism 40 formed in this way, the shape in the vicinity of the vertex 41p, which tends to be formed at a relatively acute angle, is enabled to be easily formed into a shape that is more obtuse. Consequently, cracks which may be formed at the time of manufacturing are less likely to occur. By making it possible to suppress occurrence of cracks which may be formed at the time of manufacturing, improving the manufacturability of the prism 40, and moreover, the display device, is achieved.
A surface 42b is a surface formed on the outermost side as the outer shape of the protruding portion. The surface 42b is a surface perpendicular to the incidence surface 41i. Extension lines of the surface 42b and the incidence surface 41i intersect each other at a right angle at a virtual point Pv. A configuration in which a perpendicular surface (the surface 42b) is formed in the protruding portion 42 in this way improves the manufacturability of the display device.
Specifically, the prism 40 is provided on the display surface 21 by being adhesively attached to the display surface 21, for example. In doing so, the prism 40 is adhesively attached by, for example, pressing the emitting surface 41o that is inclined relative to the incidence surface 41i, which is an adhesive surface. At the time of the pressing, the prism 40 receives a force which makes the prism 40 be displaced toward the protruding portion 42 side by the effect of the inclination. At this time, in a conventional prism which does not have a protruding portion or a perpendicular surface, a vertex or the like comes into contact with a jig at the time of manufacturing. In contrast, with the prism 40 configured such that a jig comes into contact with the protruding portion 42 or the surface 42b prior to the vertex, it is possible to reduce the possibility of cracks occurring at a place that is functionally important for display even if the prism 40 comes into contact with the jig. In addition, in the prism 40 including the surface 42b, which is the perpendicular surface, the surface 42b is intentionally made to abut against a jig at the time of installation, thereby facilitating the positioning.
A surface 42a is a surface formed to connect the surface 42b and the end portion 41e.
A surface 41d is a surface formed to connect the incidence surface 41i and the emitting surface 41o. In particular, the surface 41d is formed as a perpendicular surface perpendicular to the incidence surface 41i. As the surface 41d, which is the perpendicular surface, abuts against a jig, positioning can be easily performed.
The surface 41d is formed on a side surface opposite to the protruding portion 42. Although not illustrated, it is more preferable if the surface 41d is provided such that at least a part of the surface 41d is opposed to the surface 42b, which is the perpendicular surface, formed in the protruding portion 42. When the surfaces are provided to be opposed to each other, the manufacturability of the display device is further improved. Specifically, the prism 40 in which the perpendicular surfaces, which are at least partially opposed to each other, are formed can be easily handled since the prism 40 allows an assembly worker or an automatic assembly machine to grasp the prism 40 by the opposing portions. Therefore, improving the manufacturability of the display device can be realized.
An example in which the protruding portion 42 is formed by the surfaces and corners as described above is indicated. In particular, it is desirable that all the corners of the protruding portion 42 be formed to have an obtuse angle as illustrated in the drawing.
Further, the shape of the protruding portion 42 has been described mainly on the basis of the side view of
Note that although the side surface 43 is also exemplified as a plane in the embodiment described above, the side surface 43 may be a curved surface, an inclined surface, or the like. The corner formed at the periphery of the side surface 43 should preferably have an obtuse angle. Also by this configuration, the manufacturability of the display device is improved.
According to the embodiment described above, the following advantageous effects are achieved.
Firstly, as a first aspect, the display device D is provided with: the display unit 20 which includes the display surface 21 that emits the display light L, and emits central display light in an emission direction that is non-perpendicular to the display surface 21; and the prism 40 which is provided on the display surface 21, includes an incidence surface 41i on which the display light L is incident and an emitting surface 41o which emits the display light L, and has a thickness which is gradually increased in the emission direction, in which in the prism 40, a vertex of the emitting surface 41o is positioned to be deviated from an immediately above region, which is located immediately above the incidence surface 41i, toward the emission direction side.
According to this configuration, it is possible to prevent the prism 40 from being unnecessarily enlarged in the volume, and the manufacturability of the display device can be improved.
Secondly, as a second aspect, in the display device D indicated as the first aspect, the prism 40 forms the protruding portion 42 which is further projected toward the emission direction side with respect to the virtual side surface 41v, which connects the end portion 41e of the incidence surface 41i at the emission direction side and the vertex 41p, the protruding portion 42 is formed by the surfaces 42a, 42b, and 42c and corners, and of the corners, the vertex angle θ1 formed at the vertex 41p is more obtuse than the virtual angle θ2 formed by the virtual side surface 41v and the emitting surface 41o.
According to this configuration, it becomes easy to form the corner to be formed at the vertex 41p to be more obtuse, and the manufacturability of the display device can be improved.
Thirdly, as a third aspect, in the display device D indicated as the second aspect, the surface 42b, which is a surface that is most projected toward the emission direction side among the surfaces forming the protruding portion 42, is a perpendicular surface perpendicular to the incidence surface 41i.
According to this configuration, positioning of the prism 40 can be easily performed at the time of manufacturing, and the manufacturability of the display device can be improved.
Fourthly, as a fourth aspect, in the display device D indicated as the second aspect, the protruding portion 42 is formed by obtuse-angled corners and surfaces, from the vertex 41p to the end portion 41e.
According to this configuration, occurrence of cracks of the prism 40 can be suppressed, and the manufacturability of the display device can be improved.
Note that the present disclosure is not limited to the above embodiments and drawings. Modifications (including deletion of structural elements) may be made as appropriate as long as the gist of the present disclosure is not changed. An example of modifications will be described below.
The display device may adopt a configuration indicated below. For example,
In contrast to the prism 40, the prism 401 further includes a leg portion 41f. The leg portion 41f has a protruding shape protruding from the incidence surface 41i toward the display surface 21. The leg portion 41f may be formed to be dotted one by one at each of four corners or may be formed as a pair of linear shapes on both sides of the prism, or may be formed in an annular shape or a polygonal shape so as to surround the incidence surface 41i.
The leg portion 41f abuts against the display unit 20, for example. In a case where the display unit 20 is provided with a bezel 21a (a frame body) formed to surround the periphery of the display surface 21, preferably, the leg portion 41f should abut against the bezel 21a. The bezel 21a is formed of a metal or the like which reduces noise, static electricity, and the like, on the display surface 21.
The leg portion 41f is formed in such a shape that the thickness of an adhesive 22, which adhesively attaches the display surface 21 and the prism 401 to each other, is kept constant. That is, the leg portion 41f is formed so as to keep the relative position of the prism 401 with respect to the display surface 21 constant. The leg portion 41f may be formed so as to keep the distance between the display surface 21 and the incidence surface 41i constant.
The prism may be a prism 402 illustrated in
The surface 42c2 has commonality with the surface 42c in that the surface 42c2 is formed by connecting the emitting surface 41o and the surface 42b. Meanwhile, the surface 42c2 constitutes a curved shape. Further, the surface 42c2 is connected to the emitting surface 41o at the vertex 41p in an indifferentiable angular shape.
In this case, preferably, a vertex angle θ3 formed by the surface of the emitting surface 41o and a tangential plane of the surface 42c2 should be more obtuse than a virtual angle.
The prism may be a prism 403 illustrated in
The surface 42c3 is a curved surface formed in a shape that is constantly differentiable from the vertex 41p to the surface 42b. That is to say, the surface 42c3 constitutes a shape that smoothly connects the emitting surface 41o and the surface 42b.
Even if such a configuration in which no vertex angle is formed is adopted, the manufacturability of the display device is improved as long as the protruding portion is formed by a surface (including a curved surface) and an obtuse-angled corner.
Further, as another modification example, a configuration as described below may be adopted.
Although an example in which the emitting surface 41o has a planar shape has been indicated, the emitting surface 41o may be a curved surface.
Although an example in which the vertex 41p is formed in a linear shape with the apexes being continuous with each other has been indicated, the vertex 41p may be formed in a curved shape.
The vertex 41p need not necessarily be formed so as to traverse the emitting surface 41o.
The end portion 41e may be a curved line instead of a straight line.
Other than the above, a partial shape of the prism which is not particularly mentioned may be changed as appropriate.
In each of the above embodiments, the head-up display device 100 is mounted on a vehicle. However, an object on which the head-up display device 100 is mounted is not limited to the above, and the head-up display device 100 may be mounted on a movable body such as an airplane or a ship. Furthermore, the projection target member is not limited to the windshield 201, but may be a dedicated combiner.
Further, beams of the display light L may be crossed within an optical path by the convergence effect of a mirrors or a lens.
Also in this case, the advantageous effect of the present invention is exhibited if the prism and the display unit are configured as appropriate to correspond to the desired form of the virtual image.
For example, when beams of the display light L are to cross once within the optical path in the up-down direction, the prism and the display unit should preferably be provided upside down as compared to the case where the beams of the display light L do not cross each other.
The display light L may be projected by passing through an arbitrary mirror and lens between the display device and the projection target member. The arbitrary mirror may have a shape that is a flat surface, a concave surface, a convex surface, or a free-form surface, and the wavelength characteristic may indicate total reflection or visible light reflection. The arbitrary lens may be a lens in which the shape of the incidence surface and the emitting surface is a flat surface, a concave surface, a convex surface, or a free-form surface, and the wavelength characteristic may indicate total reflection or visible light reflection.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-211420 | Dec 2022 | JP | national |
