Head-up display device

Abstract

To provide a head-up display device that can suppress the occurrence of image blur. [Solution] The head-up display device comprises a case, a concave mirror rotatably mounted on the case around a shaft and reflecting display light representing an image, a bearing 8 having an inner ring 8a into which the shaft is inserted, and an outer ring 8b that rotates relative to the inner ring 8a, and a bearing holder fixed to the case and holding the bearing. The bearing 8 further has a rubber seal plate 8d that contacts the inner ring 8a.

Description

Technical Field

[0001] The present disclosure relates to a head-up display device.

Background Art

[0002] Patent Document 1 describes a head-up display device including a concave mirror (mirror main body) that reflects display light representing an image toward the windshield of a vehicle. In this device, the concave mirror is provided rotatably about a rotation axis.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of device, due to vibrations from the outside, the concave mirror rotates slightly, which may cause significant blurring (image blur) of the visible image.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a head-up display device capable of suppressing the occurrence of image blur.

Means for Solving the Problems

[0006] To achieve the above object, a head-up display device according to the present disclosure includes a case, a concave mirror provided rotatably about a shaft with respect to the case and reflecting display light representing an image, a bearing having an inner ring into which the shaft is inserted and an outer ring that rotates with respect to the inner ring, and a bearing holder fixed to the case and holding the bearing. The bearing further includes a rubber seal plate that contacts the inner ring. [Effects of the Invention]

[0007] According to this disclosure, the occurrence of image blur can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram of a head-up display device according to one embodiment of the present disclosure. [Figure 2] A partial perspective view of the concave mirror unit according to the same embodiment. [Figure 3] A partial cross-sectional view of a concave mirror unit according to the same embodiment. [Figure 4] A diagram illustrating the features of the head-up display device according to Example 1. [Figure 5] A diagram illustrating the effects of the head-up display device according to Example 1. [Figure 6] A diagram illustrating the features of the head-up display device according to Example 2. [Figure 7] A diagram illustrating the effects of the head-up display device according to Example 2. [Figure 8] A diagram illustrating the features of the head-up display device according to Example 3. [Figure 9] A diagram illustrating the effects of the head-up display device according to Example 3. [Modes for carrying out the invention]

[0009] One embodiment of this disclosure will be described with reference to the drawings.

[0010] The head-up display device 100 shown in FIG. 1 (hereinafter also referred to as the HUD device 100) is provided, for example, inside the dashboard of a vehicle and emits display light L toward the windshield (front glass) of the vehicle. By the display light L reflected by the windshield, a user (mainly the driver of the vehicle) can visually recognize a virtual image of the image represented by the display light L. The image visually recognized as a virtual image shows various information related to the vehicle.

[0011] The HUD device 100 includes a case 1, a display unit 2, a plane mirror 3, and a concave mirror unit 4. The concave mirror unit 4 includes a concave mirror 5 and mainly a mirror holder 6, a shaft 7, a bearing 8, and a bearing holder 9 shown in FIG. 2.

[0012] The case 1 has a box shape that opens upward and houses each part. FIG. 1 is a view of the case 1 generally seen from above. The upper part of the case 1 is covered by a dashboard not shown in the figure. The HUD device 100 emits display light L from an opening formed in the dashboard toward the windshield.

[0013] The display unit 2 emits display light L representing the image by displaying the image. The display unit 2 is located, for example, below the bottom surface 1a of the case 1 and emits display light L from an opening provided in the bottom surface 1a toward the plane mirror 3. The display unit 2 is composed of, for example, an LCD (Liquid Crystal Display). Note that the display unit 2 may use an OLED (Organic Light-Emitting Diode), or may use a reflective display device such as a DMD (Digital Micro mirror Device) or an LCOS (Liquid Crystal On Silicon).

[0014] The plane mirror 3 is located above the display unit 2 and reflects the display light L emitted from the display unit 2 toward the concave mirror 5.

[0015] The concave mirror unit 4 is configured to enable rotational driving of the concave mirror 5. The concave mirror 5 has a concave mirror surface 5a that reflects the display light L from the plane mirror 3 toward the windshield.

[0016] The mirror holder 6 holds the concave mirror 5 from the back side (the side opposite to the mirror surface 5a). The mirror holder 6 has a cylindrical support portion 6a that surrounds and supports the shaft 7. The support portions 6a project from both ends in the width direction of the concave mirror 5, and there are a pair of them. The shaft 7 is made of, for example, metal and is a columnar member formed around the axis AX. The axis AX is the rotation axis of the concave mirror 5 and also the center line of the shaft 7. The HUD device 100 includes, as a configuration not shown in the figure, a motor and a transmission mechanism such as a gear mechanism that transmits the rotational power of the motor to the mirror holder 6, and by driving the motor, the concave mirror 5 is rotationally driven around the axis AX.

[0017] The bearing 8 is composed of a ball bearing. As shown in FIG. 3, it has an inner ring 8a into which the shaft 7 is inserted, an outer ring 8b that rotates with respect to the inner ring 8a, and balls 8c that are rolling elements located between the inner ring 8a and the outer ring 8b. The shaft 7 is press-fitted into the inner ring 8a. The outer ring 8b is press-fitted into the bearing holder 9. A pair of bearings 8 are provided corresponding to the pair of support portions 6a. Since the pair of bearings 8 and their corresponding configurations are the same, the configuration corresponding to one of the bearings 8 will be mainly described below.

[0018] The bearing holder 9 is configured to hold the bearing and is formed of, for example, resin. As shown in FIG. 2, the bearing holder 9 has a holder body 9a into which the outer ring 8b of the bearing 8 is press-fitted, and a fixing portion 9b located above the holder body 9a. The fixing portion 9b is the portion of the bearing holder 9 that is fixed to the case 1, as shown in FIG. 1. The case 1 is provided with a boss (not shown) corresponding to the fixing portion 9b, and by fixing the fixing portion 9 to this boss by screwing or the like, the bearing holder 9 is fixed to the case 1. The fixing portion 9b is formed to be long in the radial direction of the bearing 8. The above is the schematic configuration of the HUD device 100.

[0019] The inventors of this application have conceived of suppressing minute rotations of the concave mirror 5 due to external vibrations by increasing the rotational torque when rotating the concave mirror 5, as described below in order: Feature 1 in Example 1, Feature 2 in Example 2, and Feature 3 in Example 3. By incorporating at least one of these features 1 to 3, the HUD device 100 can raise the resonance point (resonance frequency) associated with vibrations, thereby suppressing minute rotations of the concave mirror 5 due to vibrations and reducing image blur.

[0020] (Example 1) (Feature 1) The bearing holder 9 is fixed to the case 1 such that the outer ring 8b is tilted with respect to the center line of the shaft 7 (i.e., axis AX). Feature 1 will be explained with reference to Figure 4. In the figure, the X-axis is an axis parallel to the axis AX. The Y-axis is an axis perpendicular to the X-axis and extends in the longitudinal direction of the vehicle. To realize Feature 1, for example, the bearing holder 9 is fixed to the case 1 such that its fixing portion 9b is tilted with respect to the Y-axis. As a result, the radial direction D of the outer ring 8b, which is press-fitted into the bearing holder 9, is tilted with respect to the Y-axis. Consequently, a twisting force is applied to the outer ring 8b relative to the inner ring 8a into which the shaft 7 is press-fitted, making the axial internal clearance of the bearing 8 smaller than when no force is applied to the outer ring 8b, and increasing the resistance between the inner ring 8a and the outer ring 8b. This makes it possible to increase the rotational torque when rotating the concave mirror 5.

[0021] The structure that realizes Feature 1 is arbitrary. For example, as a structure in which the bearing holder 9 and outer ring 8b are arranged to be tilted with respect to the Y axis relative to Case 1, (i) a groove to guide the bearing holder 9, (ii) a rib to forcibly tilt the position of the bearing holder 9, etc. can be provided in Case 1.

[0022] Figure 5 shows the effect of the HUD device 100 according to Embodiment 1, which has Feature 1. This figure shows the effect of 2 [m / s] for both Embodiment 1 and the comparative example (configuration in which the bearing holder 9 is not tilted). 2This figure shows the resonance point in an experiment where vibrations of [ ] were applied. Of the two graphs, the graph with a resonance point that is Δf higher than the other graph (comparative example) is that of Example 1. From this figure, it can be seen that the resonance point can be made higher according to Example 1. Therefore, the HUD device 100 equipped with feature 1 can suppress minute rotations of the concave mirror 5 due to vibrations and reduce image blur.

[0023] (Example 2) (Feature 2) The radial internal clearance of bearing 8 is 5.0 μm to 10.00 μm (5.0 μm or more and 10.0 μm or less). Figure 6 shows the radial internal clearance δ of bearing 8. That is, feature 2 is 5.0 μm ≤ δ ≤ 10.00 μm. As a bearing 8 having this radial internal clearance δ, for example, one with an inner diameter (inner diameter of inner ring 8a) of 6 mm, an outer diameter (outer diameter of outer ring 8b) of 15 mm, and a width (width in the direction of axis AX) of 5 mm can be used.

[0024] Here, Figure 7 shows the effect of the HUD device 100 according to Example 2, which incorporates Feature 2. The method of applying vibration is the same as in Figure 5. As a comparative example, a configuration was prepared using a bearing 8 with a larger radial internal clearance δ than that of Example 2, specifically 7.5 μm ≤ δ ≤ 12.5 μm. Of the two graphs, the graph with a resonance point that is Δf higher than the other graph (comparative example) is that of Example 2. From this figure, it can be seen that the resonance point can be made higher by deliberately using a bearing 8 with a smaller radial internal clearance than that of the comparative example in Example 2. Therefore, the HUD device 100 incorporating Feature 2 can suppress minute rotations of the concave mirror 5 due to vibration and reduce image blur.

[0025] (Example 3) (Feature 3) The bearing 8 further has a rubber seal plate that contacts the inner ring 8a. Figure 8 shows the rubber seal plate 8d. In other words, the bearing 8 according to Embodiment 3 includes an inner ring 8a, an outer ring 8b, and balls 8c, in addition to the rubber seal plate 8d. This rubber seal plate 8d is annular in shape, with its outer circumference in contact with the outer ring 8b and its inner circumference in contact with the inner ring 8a. In other words, the bearing 8 according to Embodiment 3 is a contact-type bearing with a rubber seal plate 8d.

[0026] Here, Figure 9 shows the effect of the HUD device 100 according to Embodiment 3, which has Feature 3. The method of applying vibration is the same as in Figure 5. As a comparative example, a configuration using a non-contact type bearing with a metal seal plate (a bearing in which the inner circumference of the seal plate does not contact the inner ring 8a) was prepared. Of the two graphs, the graph with a resonance point that is Δf higher than the other graph (comparative example) is that of Embodiment 3. From the same figure, it can be seen that the resonance point can be made higher by deliberately using a contact type bearing with a rubber seal plate 8d in Embodiment 3. Therefore, the HUD device 100 with Feature 3 can suppress minute rotation of the concave mirror 5 due to vibration and reduce image blur.

[0027] The HUD device 100 may have only one of features 1 to 3, a combination of two features, or all of the features.

[0028] The present invention is not limited by the embodiments and drawings described above. Modifications (including the deletion of components) can be made as appropriate, without altering the essence of the invention.

[0029] In the above explanation, explanations of publicly known technical matters have been omitted where appropriate to facilitate understanding of this disclosure.

[0030] This invention allows for various embodiments and modifications without departing from the broad spirit and scope of the invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the invention. In other words, the scope of this invention is indicated not by the embodiments, but by the claims. Various modifications made within the scope of the claims and the equivalent scope of the meaning of the invention are considered to be within the scope of this invention. [Explanation of symbols]

[0031] 100... Head-up display device (HUD device) 1…Case 2...Display section 3…Plane mirror 4…Concave mirror unit 5...Concave mirror, 5a...Mirror surface 6...Mirror holder, 6a...Support part 7…Shaft 8...Bearing, 8a...Inner ring, 8b...Outer ring, 8c...Ball, 8d...Rubber seal plate 9...Bearing holder, 9a...Holder body, 9b...Fixing part L…Display light AX…Axis line D... Radial direction of the outer ring 8b

Claims

[Claim 1] The case and, A concave mirror is provided so as to be rotatable around a shaft relative to the case, and reflects display light representing an image. A bearing having an inner ring into which the shaft is inserted, and an outer ring that rotates relative to the inner ring, The case is fixed to the bearing holder which holds the bearing, The bearing further includes a rubber seal plate that contacts the inner ring. Head-up display device.

Images