JP2018173437A - Head-up display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce a change in color balance of a virtual image even when a half mirror is rotated.SOLUTION: A half mirror 40 reflects first display light 110 of a first image 12 and transmits second display light 120 of a second image to form a first virtual image 210 of the first image 12 and a second virtual image 220 of the second image 22. A display control part 73 adjusts the color balance of the first image 12 and the color balance of the second image 22 according to the rotation of the half mirror 40.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a head-up display that displays a virtual image.

  The head-up display disclosed in Patent Document 1 reflects a first display unit that displays a first image, a second display unit that displays a second image, and light of the first image, And a first mirror that is a virtual image of the first image, and a virtual image of the second image, each of which includes a half mirror that transmits the light of the second image and a projection unit that projects the light from the half mirror. A certain second virtual image is visually recognized.

  The head-up display may rotate the half mirror when the external light is not directed to the display unit or when it is desired to change the position where the first virtual image is formed.

JP 2008-003355 A

  However, the wavelength characteristics of the transmittance and reflectance of the half mirror change according to the incident angle of light. Therefore, when the incident angle of light changes, the transmittance / reflectance changes for each wavelength of light and is visually recognized. There was a problem that the color balance of the virtual image was lost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a head-up display capable of suppressing a change in color balance of a virtual image even when a half mirror is rotated. .

The present invention employs the following means in order to solve the above problems.
In the head-up display of the present invention, the half mirror reflects the first image and transmits the second image, so that the first virtual image of the first image and the second virtual image of the second image The color balance of the virtual image caused by the angle change of the half mirror is suppressed by adjusting the color balance of the first image and the color balance of the second image according to the rotation of the half mirror. This is the gist.

  The head-up display according to the first aspect of the present invention includes a first display unit that displays the first image based on the first image data, and a second display that displays the second image based on the second image data. On the optical axis of the first display light based on the first image from the first display unit and based on the second image from the second display unit A half mirror that is disposed on the optical axis of the display light and reflects and transmits the light, and the first display light that is reflected by the half mirror and the second display light that is transmitted by the half mirror are directed toward the projection member. By projecting the first virtual image of the first image and the second virtual image of the second image, an actuator for changing the angle of the half mirror, and the actuator For angle change of the half mirror The color balance of the first image and the color balance of the second image are reduced so that the amount of change in the color balance of the first virtual image and the amount of change in the color balance of the second virtual image that are changed at the same time are reduced. And a display control unit that corrects.

  According to the head-up display configured as described above, the change in the color balance of the first virtual image and the second virtual image that are generated due to the incident angle dependence of the transmittance and reflectance of the half mirror due to the rotation of the half mirror. Considering the change in color balance, the display control unit displays an image with a stronger color that becomes weaker due to a change in the angle of the half mirror, and / or weakens a color that becomes stronger due to a change in the angle of the half mirror. The image is displayed on the first display unit and the second display unit. As a result, the head-up display can suppress the change in the color balance of the virtual image even when the half mirror is rotated.

  Further, like the head-up display in the second aspect subordinate to the first aspect, the display control unit corrects the first image data and the second image data, thereby correcting the color balance of the first image. The color balance of the second image may be corrected. Specifically, the display control unit corrects the color balance of the image by changing the gradation of each color (for example, red, green, and blue) included in the image data according to the rotation of the half mirror. Thus, the color balance of the image can be easily adjusted only by changing the image data.

  Moreover, like the head-up display in the 3rd aspect subordinate to a 1st aspect or a 2nd aspect, a 1st display part and a 2nd display part are a light source which radiate | emits color light of multiple colors, and a light source And a spatial light modulation element that displays the first image and the second image by modulating the color light emitted from the light source, and the display control unit sets the light intensities of the multiple colors of color light emitted from the light source, respectively. By adjusting, the color balance of the first image and the color balance of the second image may be corrected. Specifically, the display control unit increases the output of the light source that emits the color light that is weakened by the angle change of the half mirror, and / or the color light of the color that becomes strong by the angle change of the half mirror. The output of the light source that emits light is reduced. As a result, the color balance can be adjusted in a wider range than when the color balance is adjusted with the image data.

  Moreover, like the head-up display in the 4th aspect subordinate to a 3rd aspect, it further comprises the temperature detection part which detects the temperature of a light source, and a display control part is based on the temperature which the temperature detection part detected, The light intensity of the color light emitted from the light source may be corrected. This makes it possible to adjust the color balance of the virtual image more accurately even when the temperature of the light source changes, the light output intensity changes, or the light wavelength shift occurs.

  Further, like the head-up display of the fifth aspect subordinate to any of the first to fourth aspects, it is on the optical axis of the first display light transmitted by the half mirror and reflected by the half mirror. A light intensity detection unit arranged on the optical axis of the second display light and capable of detecting the light intensity of the transmitted first display light and the reflected second display light; The color balance of the first image and the color balance of the second image may be corrected according to the detected light intensity. As described above, by arranging the light intensity detection unit, it is possible to detect the light intensity of the transmitted light of the first display light and the reflected light of the second display light, which is not used for virtual image display. It becomes possible to infer the light intensity of light used for virtual image display from the light intensity. As a result, the light intensity after being actually transmitted and reflected by the half mirror can be detected, so that the color of the first image can be more accurately determined according to the wavelength characteristics of the transmittance and reflectance of the actual half mirror. The balance and the color balance of the second image can be corrected. The display control unit provides a period for displaying only the first display unit or the second display unit, and the light intensity detection unit transmits the transmitted light of the first display light or the reflected light of the second display light. Only the light intensity can be detected, and the color balance of the first image and the color balance of the second image may be corrected based on the detection result of one light intensity. The display control unit corrects the color balance of the first image and the color balance of the second image based on the total light intensity of the transmitted light of the first display light and the reflected light of the second display light. Also good.

  The embodiments described below are used to easily understand the present invention, and those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

  FIG. 1 is a diagram showing a configuration of a head-up display (hereinafter, HUD) 1 according to an embodiment of the present invention. The HUD 1 includes, for example, a first display unit 10, a second display unit 20, a concave mirror (projection unit) 30, a half mirror 40, a folding mirror 50, an actuator 60, a control unit 70, and a light intensity detection unit 80. , And a housing 90 for storing them. The HUD 1 forms the virtual image 200 at a position through the projection member 2 viewed from the viewpoint 3 by projecting the display light 100 onto the projection member 2 that is a front windshield of the vehicle, for example. Specifically, the HUD 1 of the present embodiment projects the first display light 110 emitted from the first display unit 10 and the second display light 120 emitted from the second display unit 20. By projecting onto the member 2, a first virtual image 210 based on the first display light 110 and a second virtual image 220 based on the second display light 120 are formed. The HUD 1 is generally housed in the dashboard of the vehicle, but all or part of the HUD 1 may be disposed outside the dashboard. The HUD 1 (control unit 70) is connected to a bus 4 including an in-vehicle LAN (Local Area Network) mounted on a vehicle, and can input a part or all of vehicle information or image data from the bus 4.

  The first display unit 10 receives, for example, a first projection unit 11 including a projector using a reflective display device such as DMD or LCoS, and projection light from the first projection unit 11 and receives the first projection unit 11. And a first screen (first display surface) 13 that emits first display light 110 indicating the first image 12 toward the folding mirror 50. . The first display unit 10 displays the first image 12 on the first screen 13 based on first image data D1 input from the control unit 70 described later. The first image 12 includes an image element 14 that is visually recognized by a viewer, and is displayed in black with low brightness except for an area where the image element 14 is displayed. In addition, the 1st display part 10 changes the position which displays the 1st image 12 on the 1st screen 13, The 1st virtual image 210 based on the 1st image 12 which a viewer visually recognizes is displayed. The position can be changed.

  Similarly to the first display unit 10 described above, the second display unit 20 includes, for example, a second projection unit 21 including a projector using a reflective display device such as DMD or LCoS, and a second projection. A second screen 23 that receives the projection light from the unit 21 to display the second image 22 and emits the second display light 120 indicating the second image 22 toward a half mirror 40 described later; , Mainly composed of. The first display unit 10 displays the second image 22 on the second screen 23 based on second image data D2 input from the control unit 70 described later. The second image 22 includes an image element 24 that is visually recognized by the viewpoint 3, and is displayed in black with low brightness except for an area where the image element 24 is displayed. The second display unit 20 changes the position at which the second image 22 is displayed on the second screen 23, so that the position of the second virtual image 220 based on the second image 22 visually recognized by the viewer is displayed. Can be changed.

  The concave mirror 30 is, for example, disposed on the optical path of the first display light 110 and the second display light 120 emitted from the first display unit 10 and the second display unit 20, and is arranged in the first display. The first display light 110 and the second display light 120 emitted from the unit 10 and the second display unit 20 are reflected toward the projection target member 2. The first screen 13 of the first display unit 10 and the second screen 23 of the second display unit 20 described above are arranged closer to the concave mirror 30 than the focal length of the concave mirror 30. More specifically, when the first screen 13 and the second display unit 20 of the first display unit 10 combine the optical characteristics of the concave mirror 30 and the front windshield (transmission reflection unit) 2, Is disposed closer to the concave mirror 30 than the focal length. As a result, the first image 12 displayed on the first screen 13 is formed as the first virtual image 210, and the second image 22 displayed on the second screen 23 is formed as the second virtual image 220. Imaged.

  In addition, the concave mirror 30 is configured such that the optical path length of the first display light 110 from the first screen (first display surface) 12 of the first display unit 10 to the concave mirror 30 is the second display unit. The second display light 120 is arranged so as to be longer than the optical path length of the second display light 120 from the 20 second screen (second display surface) 22 to the concave mirror 30. Thereby, the first virtual image 210 is formed at a position distant from the second virtual image 220 as viewed from the viewer. Note that the concave mirror 30 typically enlarges the first image 12 (second image 22) and forms a first virtual image 210 (second virtual image 220). The distortion correction function for correcting the distortion of the first virtual image 210 and the second virtual image 220 generated by the curved surface 2 and visually recognizing the virtual image without distortion, the first virtual image 210 and the second virtual image 220 are given from the viewer An image forming position adjusting function for forming images at positions separated by a distance is provided. The function of the concave mirror 30 may be constituted by a plurality of mirrors. The concave mirror 30 may be replaced with a refractive optical element or a diffractive optical element, or a reflective optical element, a refractive optical element, a diffractive optical element, or the like may be replaced with a combined optical unit.

  In the half mirror 40, for example, a transflective layer such as a metal reflective film or a dielectric multilayer film is formed on one surface of a translucent substrate. The half mirror 40 reflects the first display light 110 from the first display unit 10 reflected by the folding mirror 50 toward the concave mirror 30, and the second display light 120 from the second display unit 20. Is transmitted to the concave mirror 30 side.

  The folding mirror (relay optical unit) 50 is formed of, for example, a flat plate-shaped mirror, and is disposed to be inclined on the optical path of the first display light 110 from the first display unit 10 toward the half mirror 40. The first display light 110 emitted from the display unit 10 is reflected toward the half mirror 40. The folding mirror 50 can suppress the optical path of the first display light 110 in a compact manner by folding back (reflecting) the first display light 110 from the first display unit 10. Note that the folding mirror 50 may have a curved surface instead of a flat surface. The relay optical unit 50 of the present invention is disposed on the optical path of the first display light 110 from the first display unit 10 toward the half mirror 40, and relays the first display light 110. A refractive optical system such as In the present invention, the relay optical unit 50 may be omitted.

  The actuator 60 is composed of, for example, a stepping motor or a DC motor, and changes the relative positional relationship between the first virtual image 210 and the second virtual image 220 by changing the angle of the half mirror 40, or The reflected light of the external light 300 incident on the first screen 13 is not directed toward the viewpoint 3.

  FIG. 2 shows a schematic configuration example of the control unit 70. As shown in FIG. 2, the control unit 70 includes, for example, an interface 71, a storage unit 72, a display control unit 73, and an angle control unit 74. The interface 71 is configured by an input / output communication interface connected to the bus 4, the storage unit 72 is configured by, for example, a ROM, and the display control unit 73 is configured by, for example, one or a plurality of CPUs and RAMs. For example, the interface 71 can acquire image data D, which will be described later, via the bus 4, and the storage unit 72 stores the first image data D1 and the second image data D2 based on the input image data D. The display control unit 73 reads the data from the storage unit 72 and executes a predetermined operation, whereby the first image data D1 and the second image data D2 are stored. And the first projection unit 11 and the second projection unit 21 are controlled.

  Moreover, the control part 70 may have a function as the angle control part 74 for controlling the actuator 60 as mentioned above. The storage unit 72 is associated with drive data T for adjusting the angle of the half mirror 40 according to an input signal from the vehicle ECU 5 or an operation unit (not shown), and the angle of the half mirror 40, and the first display unit 10. The first correction data C1 for correcting the color balance of the first image 12 displayed by, and the color of the second image 22 displayed by the second display unit 20, which is also associated with the angle of the half mirror 40. The second correction data C2 for correcting the balance can be stored, the angle control unit 74 controls the actuator 60 based on the drive data T, and the display control unit 73 corresponds to the angle of the half mirror 40. Based on the first correction data C1 and the second correction data C2, the color balance of the first image 12 displayed on the first display unit 10 and the second image 22 displayed on the second display unit 20 are displayed. To adjust the color balance. In the present embodiment, the control unit 70 that controls the first display unit 10 and the second display unit 20 also has a function as the angle control unit 74 for controlling the actuator. 74 may be provided separately from the control unit 70 that controls the first display unit 10 and the second display unit 20.

  The light intensity detection unit 80 includes red light of 590 [nm] to 720 [nm], 480 [nm] to 600 [nm] of light in the visible light wavelength region with wavelengths of 380 [nm] to 780 [nm]. It is composed of color sensors capable of detecting light intensity separately for green and 400 [nm] to 540 [nm]. The light intensity detector 80 is on the optical axis of the first display light 110 transmitted by the half mirror 40 and on the optical axis of the second display light 120 reflected by the half mirror 40, and transmitted through the first display light 110. The first display light 110 and the reflected second display light 120 are arranged at a position where they can be incident.

  FIG. 3 is a flowchart showing an example of the operation of the HUD 1 of the present embodiment. The HUD 1 will be described below, for example, when the vehicle is activated, when electric power is supplied to the electronic device of the vehicle, or when a predetermined time has elapsed since the activation of the vehicle or power supply of the electronic device of the vehicle. Start processing.

  In step S1, the control unit 70 determines whether a signal that triggers the rotation of the half mirror 40 is input from the vehicle ECU 5 or the operation unit via the interface 71, and when the signal is input (Yes in step S1). ), The process proceeds to step S2.

  In step S <b> 2, the angle control unit 73 reads the drive data T corresponding to the signal input in step S <b> 1 from the storage unit 72 and drives the actuator 60 based on the drive data T, thereby the angle of the half mirror 40. Adjust.

  In step S3, the display control unit 72 reads the first correction data C1 and the second correction data C2 corresponding to the angle of the half mirror 40 set in step S2, and the first image displayed by the first display unit 10 is displayed. 12 color balances and the color balance of the second image 22 displayed by the second display unit 20 are adjusted. Specifically, the display control unit 72 corrects the gradation of the first image data D1 based on the first correction data C1, and the level of the second image data D2 based on the second correction data C2. By correcting the tone, the color balance of the first image 12 and the color balance of the second image 22 are adjusted. However, when the first display unit 10 and the second display unit 20 have a light source (not shown) that emits red, green, and blue color light, and the color light emitted from the light source is deflected by the spatial light modulator. By correcting the output balance of red, green, and blue emitted from the light source based on the first correction data C1 and the second correction data C2, the color balance of the first image 12 and the second image 22 are corrected. You may adjust the color balance.

  Steps S2 and S3 may be executed in reverse order or simultaneously. When executed simultaneously, the display control unit 72 gradually adjusts the color balance of the first image 12 and the color balance of the second image 22 in accordance with the angle change of the half mirror 40. Also good.

  In step S <b> 4, the light intensity detection unit 80 detects the light intensity of the first display light 110 transmitted through the half mirror 40 and / or the light intensity of the second display light 120 reflected from the half mirror 40.

  In step S5, the display control unit 72 determines whether the color balance of the first image 12 is appropriate and the color balance of the second image 22 is appropriate based on the light intensity detected in step S4. If the color balance is not appropriate (No in step S5), the color balance of the first image 12 and the color balance of the second image 22 are adjusted again in step S6.

  Steps S4 to S6 will be described in detail. When the first display light 110 is incident on the half mirror 40, the first display light 110 is reflected by the half mirror 40 and used to generate the first virtual image 210 toward the projection unit 30. The first display light 110 is transmitted by the half mirror 40 and is projected by the projection unit 30. And the light that is not used to generate the first virtual image 210 that is not directed to. Similarly, when the second display light 120 is incident on the half mirror 40, the light transmitted through the half mirror 40 and used to generate the second virtual image 220 toward the projection unit 30 is reflected by the half mirror 40 and projected. And light that is not used to generate the second virtual image 220 that does not face the unit 30. The storage unit 72 stores in advance angle-light intensity characteristics in which the red light intensity, the green light intensity, and the blue light intensity detected by the light intensity detection unit 80 are associated with each angle of the half mirror 40. The display control unit 72 is based on the actual red light intensity, green light intensity, and blue light intensity detected by the light intensity detection unit 80, and the red color based on the angle-light intensity characteristics stored in the storage unit 72. The light intensity of the first image 12 is compared with the second light intensity so that the light intensity of the color increases if the light intensity is insufficient. The color balance of the image 22 is adjusted again.

[Modification]
In addition, this invention is not limited by the above embodiment and drawing. Changes (including deletion of constituent elements) can be added to the embodiments and the drawings as appropriate without departing from the scope of the present invention. Below, an example of a modification is described.

  In the above-described embodiment, the first display unit 10 that generates the first virtual image 210 and the second display unit 20 that generates the second virtual image 220 are provided. An image may be displayed on each of the display surface 13 and the second display surface 23. In the HUD 1 in this modification, the display control unit 73 displays the first image data D1 based on the first image 12 displayed on the first display surface 13 and the second display surface 23 on a single display unit. The second image data D2 based on the second image 22 may be output separately, or the image data D including the first image data D1 and the second image data D2 may be output.

  Further, although the HUD 1 of the above embodiment has received the image data D from the external vehicle ECU 5, various information such as vehicle information from the vehicle ECU 5, a sensor (not shown) provided in the vehicle, or in-vehicle equipment is sent to the interface 71. The display control unit 73 may generate the image data D from these various types of information.

  Further, for example, a transmissive display panel such as a liquid crystal display element, a self-luminous display panel such as an organic EL element, a scanning display device that scans with laser light, or the like may be applied to the first display unit 10. .

It is a figure which shows the example of a structure of the head-up display in embodiment of this invention. It is a figure which shows the system configuration | structure of the head-up display of the said embodiment. It is a flowchart explaining the process which the head up display of the said embodiment performs.

1 ... HUD
2 ... Projected member 3 ... View point 4 ... Bus 5 ... Vehicle ECU
DESCRIPTION OF SYMBOLS 10 ... 1st display part 11 ... 1st projection part 12 ... 1st image 12a ... Angle 13 ... 1st screen (1st display surface)
14 ... Image element 20 ... Second display unit 21 ... Second projection unit 22 ... Second image 23 ... Second screen (second display surface)
24: Image element 30: Concave mirror (projection unit)
40 ... Half mirror 50 ... Folding mirror (relay optical unit)
50a ... Angle 60 ... Actuator 70 ... Control unit 71 ... Interface 72 ... Storage unit 73 ... Display control unit 74 ... Angle control unit 80 ... Light intensity detection unit 90 ... Housing 100 ... Display light 110 ... First display light 120 ... Second display light 200 ... Virtual image 210 ... First virtual image 220 ... Second virtual image D ... Image data D1 ... First image data D2 ... Second image data

Claims (5)

A first display unit for displaying a first image based on the first image data;
A second display unit that displays a second image based on the second image data;
Light of second display light on the optical axis of the first display light based on the first image from the first display unit and based on the second image from the second display unit A half mirror arranged on the axis to reflect and transmit light;
By projecting the first display light reflected by the half mirror and the second display light transmitted by the half mirror toward the projection target member, the first virtual image of the first image and the first display light are projected. A projection unit that forms a second virtual image of the two images;
An actuator for changing the angle of the half mirror;
The color of the first image is reduced so that the amount of change in the color balance of the first virtual image and the amount of change in the color balance of the second virtual image that change according to the angle change of the half mirror by the actuator is small. A display control unit for correcting the balance and the color balance of the second image,
Head-up display. The display control unit corrects the color balance of the first image and the color balance of the second image by correcting the first image data and the second image data;
The head-up display according to claim 1. The first display unit and the second display unit are a light source that emits color light of a plurality of colors, and the first image and the second image by modulating the color light emitted from the light source. A spatial light modulation element for displaying, and
The display control unit corrects the color balance of the first image and the color balance of the second image by adjusting the light intensity of the color light emitted from the light source.
The head-up display according to claim 1 or 2. A temperature detection unit for detecting the temperature of the light source;
The display control unit corrects the light intensity of the color light emitted from the light source according to the temperature detected by the temperature detection unit.
The head-up display according to claim 3. On the optical axis of the first display light transmitted by the half mirror and on the optical axis of the second display light reflected by the half mirror, the transmitted first display light And a light intensity detector capable of detecting the light intensity of the reflected second display light,
Correcting the color balance of the first image and the color balance of the second image according to the light intensity detected by the light intensity detector;
The head-up display according to any one of claims 1 to 4.

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