JP6883991B2 - Head-up display - Google Patents

Description

The present invention relates to a head-up display, and is particularly suitable for use in a head-up display mounted on a vehicle.

In recent years, a head-up display (HUD) for minimizing the movement of the driver's line of sight and displaying necessary information during driving in an easy-to-see manner has become widespread. By displaying images showing various information (for example, vehicle speed, traveling direction, speed limit, etc.) on the head-up display, the driver can visually recognize various information without diverting his / her line of sight from the front.

Head-up displays are mainly divided into a windshield system that uses the front window as the display surface and a combiner system that uses a translucent screen called a combiner as the display surface.

In the windshield type head-up display, the display image emitted from the display in the dashboard is reflected by a concave mirror and then emitted from the opening formed on the upper surface of the dashboard in front of the driver's seat. It is designed to illuminate the front window. On the other hand, in the combiner type head-up display, the concave-shaped combiner installed in front of the driver's seat is irradiated with a display image from a display installed at a position facing the combiner.

The driver can visually recognize the virtual image of the image reflected on the display surface of the front window or the combiner as if it were enlarged and displayed in front of the display surface. Recently, in addition to the conventional near-viewpoint display (virtual image distance: about 2 to 3 m), there is an increasing demand for a far-viewpoint display (virtual image distance: 8 m or more). For example, there is a demand for a perspective switching display between a near-viewpoint display and a far-viewpoint display, and a two-layer display (for example, the upper half of the display surface is a far-viewpoint display and the lower half is a near-viewpoint display).

Conventionally, a head-up display capable of performing a distant viewpoint display is known (see, for example, Patent Documents 1 and 2). The head-up display described in Patent Document 1 makes it possible to display a virtual image farther by lengthening the optical path of the optical system (see paragraph [0011]). Further, the head-up display described in Patent Document 2 makes it possible to adjust the optical path length by physically moving the display and the concave mirror.

Japanese Unexamined Patent Publication No. 2013-47698 Japanese Unexamined Patent Publication No. 6-115381

However, in the technique described in Patent Document 1, the volume of the optical unit is increased by the length of the optical path, and the head-up display cannot be miniaturized. Therefore, there is a problem that it is difficult to store the head-up display in the dashboard of the vehicle.

Further, in the technique described in Patent Document 2, there is a problem that a large motor or gear is required to physically move the display or the concave mirror, and the head-up display cannot be miniaturized. .. In addition, there are problems such as noise when operating the motor and gears and rattling of the display. Further, since it takes time to operate the motor and the gear, there is also a problem that it takes time to change the virtual image distance.

The present invention has been made to solve such a problem, and an object of the present invention is to enable a long-distance display to be realized with a small device configuration. Another object of the present invention is to enable switching between near-viewpoint display and far-viewpoint display in a short time without causing noise noise or rattling of the display.

In order to solve the above-mentioned problems, in the present invention, a display, a display surface for displaying the image projected by the display, and a reflector for reflecting the light emitted from the display and guiding the light emitted from the display to the display surface. In the head-up display provided with the above, the reflecting mirror has a first electrode surface and a second electrode surface at a position separated from the first electrode surface, and has a first electrode surface and a second electrode surface. By controlling the voltage applied to the electrode surface , both the first electrode surface and the second electrode surface can be selectively mirrored.

According to the present invention configured as described above, the reflection position is electrically changed by controlling the voltage applied to the electronic device used for the reflector arranged in the optical path from the display to the display surface. , The optical path length can be made variable. As a result, by controlling the optical path length to be long, the virtual image distance can be lengthened and the distant viewpoint display can be performed. Further, if the optical path length is controlled to be short, the virtual image distance can be shortened and the near-viewpoint display can be performed. As described above, according to the present invention, it is not necessary to physically increase the optical path length, so that the device can be miniaturized. Further, since there is no physical movement mechanism, it is possible to switch between the near-viewpoint display and the far-viewpoint display in a short time without causing noise noise or rattling of the display.

It is a figure which shows the whole structure example of the head-up display by this embodiment. It is a schematic cross-sectional view which shows the structure of the electrodeposition device by this embodiment. It is a figure for demonstrating the action which occurs when the voltage is applied to the electrode of the electrodeposition device by this Embodiment. It is a figure which shows the operation example when the plane mirror is constructed by the electrodeposition device of this embodiment. It is a figure which shows the example of the case where the plane mirror is constructed by using a plurality of electrodeposition devices. It is a figure which shows the configuration example when the electrode of an electrodeposition device is divided and controlled independently.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration example of a head-up display according to the present embodiment. The head-up display of the present embodiment is mounted on a vehicle and is a windshield type head-up display that displays various information on the display surface 21 of the front window 200 in front of the driver's seat.

As shown in FIG. 1, the optical unit 100 arranged on the dashboard of a vehicle includes a display 11, a plane mirror 12, a concave mirror 13, and an exit window 14. The emitted light from the display 11 is reflected by the plane mirror 12 and the concave mirror 13 which is a magnifying optical system, passes through the exit window 14, and is reflected toward the driver by the display surface 21 on the front window 200. For the driver, the virtual image 300 displayed in front of the front window 200 is visually recognized.

The display 11 projects an image to be displayed. As the display 11, for example, a laser projector, a liquid crystal display, or the like is used. The plane mirror 12 and the concave mirror 13 correspond to the reflecting mirrors in the claims, and reflect the light emitted from the display 11 and guide the light emitted from the display 11 to the display surface 21 of the front window 200. The plane mirror 12 reflects the light emitted from the display 11. The concave mirror 13 further reflects the light reflected by the plane mirror 12.

The display surface 21 displays the image projected by the display 11 by irradiating the light of the display image projected from the display 11 through reflection by the plane mirror 12 and the concave mirror 13. The driver can visually recognize the virtual image 300 of the displayed image as if the image displayed on the display surface 21 is enlarged and displayed in front of the front window 200.

In the present embodiment, at least one of the plane mirror 12 and the concave mirror 13 is composed of the electrodeposition device (an example of an electronic device in the claims) described below. The electrodeposition device has a first electrode surface and a second electrode surface at a position separated from the first electrode surface, and a voltage applied to the first electrode surface and the second electrode surface. It is an electronic device capable of selectively making either one of the first electrode surface and the second electrode surface into a mirror surface state by the control of.

FIG. 2 is a schematic cross-sectional view showing the structure of the electrodeposition device 30. As shown in FIG. 2, the electrodeposition device 30 includes an upper substrate 31a composed of an upper transparent substrate 32a and an upper transparent electrode 33a (first electrode surface), a lower transparent substrate 32b, and a lower transparent electrode 33b (first transparent electrode surface). The lower substrate 31b is composed of the lower substrate 31b (2 electrode surfaces), and the electrolyte layer 34 between the electrodes 33a and 33b. The upper substrate 31a and the lower substrate 31b are arranged so as to be separated from each other substantially in parallel, and the electrolyte layer 34 is arranged between them. The upper transparent electrode 33a and the lower transparent electrode 33b are electrodes having a smooth surface. A specific method for manufacturing the electrodeposition device 30 is described in, for example, Japanese Patent Application Laid-Open No. 2015-555805.

The electrodeposition device 30 configured in this way is driven by applying a DC voltage between the upper transparent electrode 33a and the lower transparent electrode 33b. FIG. 3 is a diagram for explaining the action that occurs when a voltage is applied to the electrodes 33a and 33b. As an example, as shown in FIG. 3, when the upper transparent electrode 33a is grounded to serve as a cathode and a DC voltage is applied to the lower transparent electrode 33b to serve as an anode, Ag contained in the electrodeposition material becomes a cathode. It precipitates on the upper transparent electrode 33a to form a silver thin film. The silver thin film acts as a mirror surface and specularly reflects the light incident on the electrodeposition device 30. The silver thin film deposited on the upper transparent electrode 33a disappears from the upper transparent electrode 33a with the passage of time due to the release of the applied voltage.

On the contrary, when the lower transparent electrode 33b is grounded to serve as a cathode and a DC voltage is applied to the upper transparent electrode 33a to serve as an anode, Ag contained in the electrodeposition material is deposited on the lower transparent electrode 33b. And form a thin film of silver. When no voltage is applied to the electrodes 33a and 33b, Ag is not deposited on both electrodes 33a and 33b. Therefore, the light incident on the electrodeposition device 30 passes through both electrodes 33a and 33b. As described above, the electrodeposition device 30 is a mirror device that commutatively realizes a mirror state (reflection state) and a transparent state by applying / not applying a DC voltage.

FIG. 4 is a diagram showing an operation example when the plane mirror 12 is configured by the above electrodeposition device 30. As shown in FIG. 4, the plane mirror 12 configured by the electrodeposition device 30 is installed at an angle that reflects the light emitted from the display 11 and guides it to the concave mirror 13.

FIG. 4A shows an optical path when a voltage is applied so that the lower transparent electrode 33b serves as a cathode. In this case, the light emitted from the display 11 is reflected by the lower transparent electrode 33b and guided to the concave mirror 13. On the other hand, FIG. 4B shows an optical path when a voltage is applied so that the upper transparent electrode 33a serves as a cathode. In this case, the light emitted from the display 11 is reflected by the upper transparent electrode 33a, which is farther from the display 11 than the lower transparent electrode 33b, and is guided to the concave mirror 13.

As described above, the optical path length changes between the case of FIG. 4 (a) in which the lower transparent electrode 33b is used as a cathode and the case of FIG. 4 (b) in which the upper transparent electrode 33a is used as a cathode. When performing a short-viewpoint display in which the distance to the virtual image 300 is short, the optical path length is shortened by using the lower transparent electrode 33b as a cathode as shown in FIG. 4A. On the other hand, in the case of performing a distant viewpoint display in which the distance to the virtual image 300 is long, the optical path length is lengthened by using the upper transparent electrode 33a as a cathode as shown in FIG. 4 (b).

When the electrodeposition device 30 is used for the plane mirror 12, if the optical path length is changed by 2 cm, the virtual image distance changes by about 3 to 4 m (there is a slight difference depending on the specifications of the concave mirror 13). The amount of change in the virtual image distance between the near and far viewpoints is determined by the distance between the upper transparent electrode 33a and the lower transparent electrode 33b, but it is necessary to leave at least about 1 cm for the purpose of preventing a short circuit when a voltage is applied. .. Thereby, the perspective switching display between the near-viewpoint display and the far-viewpoint display can be realized depending on which of the upper transparent electrode 33a and the lower transparent electrode 33b is used as the cathode.

FIG. 5 is a diagram showing an example in which the plane mirror 12 is configured by using a plurality of (three as an example) _{electrodeposition devices 30 -1} to 30 _-3. As shown in FIG. 5, three _{electrodeposition devices 30 -1} to 30 _-3 may be arranged so as to selectively apply a voltage to any one of the electrodeposition devices.

In the example of FIG. 5, with respect to electro-deposition device 30 _-2 middle shows a state where the lower transparent electrode 33b is applied a voltage such that the cathode. Since this state, no voltage is applied for electrodeposition device 30 _-3 bottom, the two electrodes 33a, 33b is in the transparent state. Therefore, the light emitted from the display 11 passes through the _{bottom electrodeposition device 30-3.} The light transmitted is reflected by the electrodeposition device 30 _-2 lower transparent electrode 33b in the middle, which is the mirror state is guided to the concave mirror 13.

In the case of the configuration as shown in FIG. 5, when a _{voltage is applied to the lowermost electrodeposition device 30-3 so} that the lower transparent electrode 33b serves as a cathode, the optical path length becomes the shortest. On the other hand, _{when a voltage is applied to the uppermost electrodeposition device 30 -1 so} that the upper transparent electrode 33a serves as a cathode, the optical path length becomes the longest. In this way, the maximum optical path length difference can be increased, and a far-view display with a considerably long virtual image distance can be realized. In addition, when three _{electrodeposition devices 30 -1} to 30 _-3 are used, six types of optical path lengths can be set, so it is not possible to switch between the near-viewpoint display and the far-viewpoint display. , 6-step perspective switching display can be performed.

FIG. 6 is a diagram showing a configuration example in the case where the electrodes of the electrodeposition device 30 are divided and independently controlled. As shown in FIG. 6, a plurality of _{electrodeposition devices 30 -1} to _30-3 are arranged in an overlapping manner, and n upper transparent electrodes 33a and n lower transparent electrodes 33b are provided for each electrodeposition device. It is divided into (two in the example of FIG. 6) to form n sets of divided electrode surfaces. Then, a voltage is selectively applied to any one of the n sets of divided electrode surfaces of any one electrodeposition device, and n sets of n sets of other electrodeposition devices different from the voltage are selectively applied. A voltage may be selectively applied to any one set of the divided electrode surfaces.

That is, the upper transparent electrode 33a is divided into two divided electrode surfaces 33a- _L and 33a- _R , and the lower transparent electrode 33b is also divided into two divided electrode surfaces 33b- _L and 33b- _R . In this configuration, either the upper divided electrode surface 33a _-L or the lower divided electrode surface 33b _-L serves as a cathode with respect to one set of the divided electrode surfaces 33a- _L and 33b- _L. It is possible to apply a voltage. _{Alternatively} , a voltage is applied to the other set of split electrode surfaces 33a-R and 33b- _{R so} that either the upper split electrode surface 33a- _R or the lower split electrode surface 33b- _R serves as a cathode. Is possible.

In the example of FIG. 6, one set of divided electrodes face 33a _-L in electrodeposition device 30 _-1 top, relative 33b _-L, such that the upper divided electrodes face 33a _-L is cathode voltage It applies a, electrodeposition device 30 other in _-3 pairs of split electrode surface 33a _-R bottom, relative 33b _-R, a voltage such that the lower transparent electrode 33b _-R a cathode The applied state is shown. In this case, the far-view display is realized by the optical path passing through _{the top electrodeposition device 30 -1} , and at the same time, the near-view display is realized by the optical path passing through the _{bottom electrodeposition device 30 -3.} Will be done. That is, it is possible to realize a two-layer display in which the upper half of the display surface 21 is a far-viewpoint display and the lower half is a near-viewpoint display.

The voltage application state of FIG. 6 shows the case where the difference between the optical path length of the far-viewpoint display and the optical path length of the near-viewpoint display is the largest. By applying a voltage in another combination, it is possible to change the combination of the virtual image distance of the far-viewpoint display and the near-viewpoint display in various ways. Here, it is not essential to apply a voltage in combination with the split electrode surfaces 33a- _L , 33b- _L of one set and the split electrode surfaces 33a- _R , 33b- _{R of the other set.} For example, in the example of FIG. 6, for the electrodeposition device 30 _-3 at the bottom, it is possible to apply a voltage one set of divided electrodes face 33a _-L, relative 33b _-L.

As described in detail above, in the present embodiment, the display 11, the display surface 21 for displaying the image projected by the display 11, and the display surface 21 by reflecting the light emitted from the display 11. In a head-up display including a guiding plane mirror 12 and a concave mirror 13, at least one of the flat mirror 12 and the concave mirror 13 is composed of an electrodeposition device 30.

According to the present embodiment configured in this way, the reflection position can be electrically changed and the optical path length can be made variable by controlling the voltage applied to the electrodeposition device 30. As a result, by controlling the optical path length to be long, the virtual image distance can be lengthened and the distant viewpoint display can be performed. Further, if the optical path length is controlled to be short, the virtual image distance can be shortened and the near-viewpoint display can be performed.

As described above, according to the present embodiment, it is not necessary to physically increase the optical path length between the display 11 and the plane mirror 12, the space mirror 12 and the concave mirror 13, and the like, so that the optical unit 100 can be downsized. Can be planned. In addition, since there is no physical movement mechanism, there is no noise or rattling of the display when switching between near-view display and far-view display, and switching between near-view display and far-view display can be performed in a short time. It can be carried out.

Further, according to the present embodiment, since the electrodeposition device 30 becomes transparent when no voltage is applied, the following secondary effects can be obtained. That is, damage to the display 11 can be avoided in the backlit path during parking. Therefore, the opening / closing mechanism of the exit window 14 for avoiding damage to the display 11 becomes unnecessary. Further, the movable mechanism of the plane mirror 12 and the concave mirror 13 for avoiding damage to the display 11 becomes unnecessary. Further, since the movable range of the concave mirror 13 can be reduced and the position resolution can be increased, the vertical position of the display can be finely adjusted.

In the above embodiment, the windshield type head-up display has been described as an example, but the same invention can be applied to the combiner type head-up display.

In addition, the above embodiments are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from its gist or its main features.

11 Display 12 Plane mirror (reflector)
13 Concave mirror (reflector)
14 Exit window 21 Display surface 30 Electrodeposition device (electronic device)
33a Upper transparent electrode (first electrode surface)
33b Lower transparent electrode (second electrode surface)

Claims (4)

A display, a display surface for displaying an image projected by the display, and a reflector for reflecting light emitted from the display and guiding the light emitted from the display to the display surface are provided.
The reflecting mirror has a first electrode surface and a second electrode surface at a position separated from the first electrode surface, and is applied to the first electrode surface and the second electrode surface. A head-up display characterized by being composed of an electronic device capable of selectively mirroring both the first electrode surface and the second electrode surface by controlling voltage. The reflector includes a plane mirror that reflects the light emitted from the display and a concave mirror that further reflects the light reflected by the plane mirror, and at least one of the plane mirror and the concave mirror is configured by the electronic device. The head-up display according to claim 1. The head-up display according to claim 1 or 2, wherein a plurality of the electronic devices are arranged in a stack, and a voltage is selectively applied to any one of the electronic devices. The first electrode surface and the second electrode surface are each divided into n pieces to form n sets of divided electrode surfaces, and a plurality of the electronic devices are arranged so as to be possessed by any one of the electronic devices. A voltage is selectively applied to any one of the n sets of divided electrode surfaces, and any one set of the n sets of divided electrode surfaces of another electronic device different from the above one electronic device. The head-up display according to claim 1 or 2, wherein a voltage is selectively applied to the head-up display.

Images