JP2016062095A - Laser scan type display device and head-up display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser scan type display device capable of suppressing the performance reduction of a laser light source.SOLUTION: A light source 110 emits laser light. A scanning part 120 scans the laser light emitted from the light source 110, to generate an information image M. A light source temperature detection part 111 estimates the temperature T of the light source 110. When it is determined that the temperature T of the light source 110 estimated by the light source temperature detection part 111 is a predetermined threshold T1 or more, a control part 300 reduces and/or not displays at least a part of the information image M, to reduce the driving amount of the light source 110.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laser scanning display device that generates an image by two-dimensionally scanning a laser, and a head-up display device using the laser scanning display device.

For example, Patent Document 1 discloses a laser scanning display device that generates an image by scanning laser light two-dimensionally. In such a laser scanning display device, a laser output device outputs laser light having a desired light intensity, and a scanning unit scans the laser light two-dimensionally to generate an image on a screen. .

JP 2013-15738 A

Such a laser scanning display device uses a semiconductor laser as a light source, and when incorporated in a device mounted on a vehicle such as a head-up display device, it may be used in a high temperature environment. When a semiconductor laser continues to be used in a high temperature environment, the performance may be degraded.

Therefore, in view of the above-described problems, an object of the present invention is to provide a laser scanning display device and a head-up display device in which the performance degradation of the laser light source is suppressed.

The present invention employs the following means in order to solve the above problems.
That is, the laser scanning display device according to the first aspect of the present invention includes a light source that emits laser light, a scanning unit that generates a display image by scanning the laser light emitted from the light source, and the light source. Temperature estimation means for estimating the temperature;
A control unit that controls the light source, and the control unit reduces or reduces at least a part of the display image when it is determined that the temperature of the light source estimated by the temperature estimation unit is equal to or higher than a predetermined threshold value. / And non-display reduces the drive amount of the light source.

  A head-up display device according to a second aspect of the present invention includes a laser scanning display device described above and a relay optical system that directs display light indicating the display image generated by the laser scanning display device to a transmission / reflection surface. And comprising.

According to the laser scanning display device and the head-up display device of the present invention, it is possible to suppress the performance degradation of the laser light source.

It is a figure for demonstrating the structure of the HUD apparatus which concerns on 1st embodiment of this invention. It is a figure which shows the display image which the laser scanning display apparatus in the said embodiment produces | generates. It is a flowchart explaining the display process in the HUD apparatus of the said embodiment. It is a figure for demonstrating the data which linked | related temperature and the number of information images of the said embodiment. It is a figure which shows the example of a display of a display image at the time of performing the high temperature display process in the said embodiment. It is a flowchart explaining the display process in the HUD apparatus of 2nd embodiment. It is a figure which shows the example of a display of a display image at the time of performing the high temperature display process in the said embodiment. It is a figure explaining the change of an information image based on time passage after temperature in a HUD device of the present invention becomes less than a threshold.

First Embodiment Hereinafter, with reference to the drawings, a first embodiment of a laser scanning display device of the present invention and a head-up display device (hereinafter referred to as a HUD device) equipped with the laser scanning display device will be described. explain.

As shown in FIG. 1, the HUD device 1 directs the laser scanning display device 100 that displays the information image M and the information image M displayed by the laser scanning display device 100 to the windshield (transmission reflection surface) of the vehicle. A relay optical system 200. The display light L indicating the information image M is reflected toward the observer by the windshield, so that the observer can visually recognize the virtual image indicating the information image M. Since the windshield is transmissive, the observer can visually recognize the virtual image together with the real scene through the windshield.

The laser scanning display device 100 receives a light source 110 that emits synthetic laser light C, a scanning unit 120 that scans the synthetic laser light C emitted from the light source 110 in a two-dimensional direction, and light that the scanning unit 120 scans. And a screen 130 for displaying the information image M.

The light source 110 includes a light source that emits red laser light, a light source that emits green laser light, and a light source that emits blue laser light. Laser light emitted from each light source travels in the direction of the scanning unit 120 as synthetic laser light C whose optical axes are aligned by an optical axis adjusting unit (not shown). The light source 110 emits a synthesized laser beam C having a desired light intensity at a desired timing through a driver circuit (not shown) under the control of the control unit 300 described later. The light source 110 includes a light source temperature detection unit 111 that detects the temperature T of the light source 110. Note that the light source 110 of the present embodiment may be configured to emit, for example, four or more colors of light including white or yellow, or may be configured to emit only two colors of light. .

The light source temperature detection unit 111 outputs temperature information regarding the light source 110 to the control unit 300 described later. The light source temperature detection unit 111 is an example of a temperature estimation unit described in the claims of the present invention. When the temperature T of the light source 110 based on the temperature information output from the light source temperature detection unit 111 exceeds a predetermined threshold T1, the control unit 300 hides a part of the information image M (high temperature display process). ). That is, the control unit 300 reduces the driving amount of the light source 110 when the temperature T of the light source 110 exceeds a predetermined threshold T1. Thereby, it can prevent that the light source 110 drives for a long time in a high temperature environment, and can suppress the performance fall of the light source 110. FIG. This “high temperature display process” will be described in detail later.

The scanning unit 120 is configured by a MEMS (Micro Electro Mechanical System) mirror or the like, receives the combined laser light C from the light source 110 under the control of the control unit 300 described later, and receives the received combined laser light C on the screen 130. Scan up in two dimensions. As a result, the information image M is displayed on the screen 130.

The screen 130 displays the information image M on the front side by receiving and transmitting the synthetic laser light C scanned by the scanning unit 120 on the back side. The screen 130 is configured by, for example, a holographic diffuser, a microlens array, a diffusion plate, and the like, and functions as an exit pupil expander that expands the exit pupil of the synthetic laser light C.

The relay optical system 200 includes a plane mirror 210, a concave mirror 220, and the like, and directs display light L indicating the information image M displayed on the screen 130 toward the windshield.

The control unit 300 is a processing unit 310 having one or a plurality of microprocessors, a microcontroller, an ASIC, an FPGA, any other IC, a rewritable RAM, a read-only ROM, an EEPROM, and a nonvolatile memory. And a storage unit 320 having one or a plurality of memories that can store programs and data such as a flash memory, and is connected to the vehicle ECU 500 via a network unit 400 such as CAN bus communication. The control unit 300 is mounted on a printed circuit board (not shown) provided inside or outside the housing of the HUD device 1.

The processing unit 310 receives image data for generating the information image M from the vehicle ECU (image data generation unit) 500 via the network unit 400, and based on the image data, the light source 110, the scanning unit 120, and the like. To generate a desired information image M. The information image M includes a plurality of information images M. As shown in FIG. 2, the information image M includes, for example, a speed information image M3 indicating the speed of the vehicle, a warning information image M2 displaying the warning information of the vehicle, and a navigation information image M3 indicating the guide route to the destination. It is a lane information image M4 that displays information on a traveling lane such as a speed limit. Normally, the information image M generated on the screen 130 is distorted in advance so that the viewer can visually recognize the undistorted virtual image V in consideration of curved surfaces such as the windshield and the concave mirror 220 of the HUD device 1. However, it is not distorted for easy viewing. The processing unit 310 inputs temperature information of the light source 110 from the light source temperature detection unit 111 and executes a high temperature display process for limiting display based on the temperature T of the light source 110.

The storage unit 320 stores in advance information image number limit data in which the temperature T and the number of information images N are associated, priority data of the information image M, and the like. The priority data is, for example, data that is ordered in the order of speed information image M1, warning information image M2, navigation information image M3, and lane information image M4 from the higher priority.

The above is the HUD device 1 of the present embodiment. The operation of the HUD device 1 will be briefly described. The processing unit 310 inputs image data from the vehicle ECU 500 and drives the light source 110 based on the image data. As a result, the combined laser beam C is output, and the scanning unit 120 scans the combined laser beam C output from the light source 110 to generate the information image M on the screen 130. The display light L indicating the information image M generated on the screen 130 is directed toward the observer by the relay optical system 200, and makes the observer visually recognize a virtual image of the information image M. Note that the processing unit 310 performs a high-temperature display process for limiting display based on the temperature T of the light source 110 detected by the light source temperature detection unit 111.

From this, the high temperature display process in this embodiment is demonstrated using FIG. 3 thru | or 5. FIG. FIG. 3 is a flowchart of the display process including the high temperature display process of the present embodiment, and FIG. 4 is a diagram showing the information image number limit data in which the temperature T and the information image number N are associated with each other. FIG. 5 is a diagram illustrating a state of the information image M generated when the high temperature display process is performed.

The processing unit 310 starts display processing after the HUD device 1 is activated, and ends display processing when the HUD device 1 is terminated.

When the display process is started, in step S <b> 10, the processing unit 310 receives temperature information from the light source temperature detection unit 111 and detects the temperature T of the light source 110.

In step S <b> 20, the processing unit 310 compares the detected temperature T of the light source 110 with a threshold value T <b> 1 stored in the storage unit 320 in advance. When the temperature T is lower than the threshold value T1 (NO in step S20), the process proceeds to step S30 (normal display process).

In step S30 (normal display processing), the processing unit 310 sets the number of information images N so as not to be limited, and controls the light source 110 so as to display all the information images M input from the vehicle ECU 500. M (virtual image V) is displayed.

On the other hand, when the temperature T is equal to or higher than the threshold T1 (YES in step S20), the process proceeds to step S40 (high temperature display process). In step S40 (high temperature display process), the processing unit 310 limits the number of information images N in accordance with the temperature T of the light source 110 based on the information image number limit data as shown in FIG. When the temperature T reaches the threshold value T1, the processing unit 310 reads the information image number limit data stored in advance in the storage unit 320, sets the number N of displayable information images, and sets the priority of each information image. The information image M not to be displayed is determined based on the priority data for determining. When the temperature T becomes equal to or higher than the maximum threshold value Ts, the processing unit 310 does not decrease the number N of information images even if the temperature T increases beyond that.

A specific display example will be described with reference to FIG. FIG. 5A is a display example when the temperature T is equal to or higher than the threshold value T1 and the high temperature display process is executed. The processing unit 310 reads, from the storage unit 320, information image number restriction data when the threshold value is greater than or equal to the threshold value T1 and less than the threshold value T2. In the present embodiment, when the number of information images is equal to or greater than the threshold value T1 and less than the threshold value T2, the number N of information images is set to three. Therefore, as shown in FIG. When the temperature T is equal to or higher than the threshold T2, the processing unit 310 reads information image number limit data from the storage unit 320. In the present embodiment, when the number is equal to or greater than the threshold value T2, the number N of information images is set to two, so that the third and subsequent priorities are not displayed as shown in FIG. FIG. 5C shows a display example when the temperature T becomes equal to or higher than the maximum threshold value Ts, and the processing unit 310 further increases the temperature T when the temperature T becomes equal to or higher than the maximum threshold value Ts. However, the number of information images N is not changed. In this embodiment, since the number N of information images when the temperature T is equal to or higher than the maximum threshold value Ts is 1, only one speed information image M1 indicating the vehicle speed with the highest priority is displayed.

As described above, the laser scanning display device 100 and the HUD device 1 including the laser scanning display device 100 according to the present embodiment estimate the temperature T of the light source 110 by the light source temperature detection unit 111, and the temperature of the light source 110. When T rises above the threshold value T1, the number N of information images to be displayed is reduced. With such a configuration, when the temperature T of the light source 110 becomes high, the information image M is drawn for one frame. Since the driving amount of the light source 110 can be reduced, it is possible to prevent the performance degradation or damage of the light source 110 due to use at high temperatures.

In addition, since the information image M with low priority is not displayed, the light source 110 can be protected while providing necessary information to the observer.

[Modification] The present invention is not limited to the above embodiments and drawings. 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.

(Second Embodiment) In the HUD device 1 in the first embodiment, the number N of information images to be displayed is decreased based on the increase in the temperature T. However, the HUD device 1 in the second embodiment The difference is that the display area A of the information image M is reduced based on the increase in T. That is, in the second embodiment, the storage unit 320 stores data in which the display area A of each information image M is associated with the temperature T, and the processing unit 310 is configured based on the temperature T of the light source 110. The display area A of the information image M is reduced.

Below, the display process of the HUD apparatus 1 of 2nd embodiment is demonstrated using FIG. FIG. 6 is a flowchart of the display process according to the second embodiment. FIG. 7 is a diagram for explaining the state of the virtual image V that is visually recognized when the high-temperature display process is performed. FIG. 7B shows the state of the virtual image V in the normal display process. FIG. 7B shows the state of the information image M in the high temperature display process when the temperature T is equal to or higher than the threshold T1, and FIG. It is a mode of the information image M in the high-temperature display processing when T is equal to or higher than the threshold T2 higher than the threshold T1. In addition, the same code | symbol is attached | subjected to the location similar to above-described embodiment, and description is abbreviate | omitted.

In step S30a (normal display processing), the processing unit 310 sets the display area A so as not to be limited, and the light source 110 is displayed without changing the display area A of each information image M input from the vehicle ECU 500. And the information image M is displayed.

On the other hand, if the temperature T is equal to or higher than the threshold T1 (YES in step S20), the process proceeds to step S40a (high temperature display process). In step S40a, the processing unit 310 limits the display area A of each information image M in accordance with the temperature T. When the temperature T reaches the threshold value T1, the processing unit 310 reads data in which the display area A of each information image M is associated with the temperature T stored in advance in the storage unit 320, and the display area of each information image M is read out. A is determined.

A specific display example will be described with reference to FIG. FIG. 7B is a display example when the temperature T is equal to or higher than the threshold T1 and the high temperature display process is executed. The processing unit 310 reads the display area A of each information image M when the threshold value T1 is greater than the threshold value T2 and less than the threshold value T2. In the present embodiment, when the threshold value T1 is greater than or equal to the threshold value T2, the display area A is set to be reduced in the speed information image M1, so that the display area of the speed information image M1 is displayed as shown in FIG. A becomes smaller. Further, in the present embodiment, when the temperature T is equal to or higher than the threshold value T2, the warning information image M2 and the lane information image M4 are set to reduce the display area A, which is illustrated in FIG. Thus, the warning information image M2a and the lane information virtual image V4a with the display area A reduced are displayed. With such a configuration, when the temperature T of the light source 110 becomes high, the driving amount of the light source 110 during drawing of one frame of the information image M can be reduced. Decline and damage can be prevented.

(Third embodiment) The HUD device 1 according to the third embodiment is different in that the drive amount is limited for each light source 110 that emits laser beams of different colors based on the increase in temperature T. That is, in the third embodiment, the storage unit 320 stores data in which the temperature T and the upper limit of the driving amount for each light source 110 that emits laser light of a different color are stored. Based on the temperature T of 110, the drive amount for each light source 110 is limited.

Specifically, for example, when the drive amount of the light source 110 that emits green laser light when generating the one-frame information image M exceeds the upper limit of the drive amount determined based on the temperature T, green The information image M that uses a lot of laser light is not displayed or / and the display area A is reduced. In this way, the drive amount for each light source 110 that emits laser light of different colors is monitored, and the information image M is hidden so as not to exceed the upper limit of the drive amount determined based on the temperature T of the light source 110. Alternatively, by reducing the display area A, it is possible to reliably protect each light source 110 without restricting the display of the information image M.

Further, the limit amount applied to the number N of information images to be hidden and the display area A of the information image M in the above embodiment may be adjusted based on the dimming rate of the HUD device 1. The HUD device 1 includes an illuminance sensor (not shown) that detects the illuminance of the outside world, and determines the dimming rate of the HUD device 1 according to the illuminance detected by the illuminance sensor. When the dimming rate is low, that is, when the information image M with low luminance is displayed, the load in driving the light source 110 is small, so the limit amount determined according to the temperature T of the light source 110 is small. However, when the dimming rate is high, that is, when the information image M having high luminance is displayed, the load in driving the light source 110 is large, and thus the limit amount determined according to the temperature T of the light source 110 is set. This needs to be increased, so that each light source 110 can be reliably protected without excessively restricting the display of the information image M.

Further, the processing unit 310 may lower the threshold value T1 for starting the high-temperature display process when the illuminance becomes larger than a predetermined value. With such a configuration, when the external light is strong, the driving of the light source 110 can be limited before the temperature rises due to the external light, and the driving amount of the light source 110 in a high temperature environment is reduced, and each light source 110 is reduced. Can be reliably protected.

The HUD device 1 starts the high-temperature display process for hiding the information image M or reducing the display area A, and / or is performing the high-temperature display process, and / or the high-temperature display process. In the case of canceling, the notification image indicating the state or the reason why the HUD device 1 is at a high temperature or / and the driving amount of the light source is reduced, such as “HUD High Temp”, “Derating”, “Cancel Derating”, etc. M5 (see FIG. 8B) may be displayed to notify the observer why the information image M is not displayed or the display area A is small. Specifically, for example, when the processing unit 310 performs the high temperature processing, the processing unit 310 starts the high temperature processing to the image generation unit (for example, the vehicle ECU) 500, or executes the high temperature processing, or performs the high temperature processing. A signal indicating that it is released is output. When receiving the signal, the image data generation unit 500 generates the image data so as to display the notification image M5. Note that when the high temperature processing is canceled, the processing unit 310 outputs a signal indicating the cancellation of the high temperature processing to the image data generation unit 500 to hide the notification image M5. With such a configuration, it is possible to reduce the uncomfortable feeling given to the observer by suddenly non-displaying (displaying) the information image M or reducing (displaying) the display area A.

In addition, when the high temperature display process is started or the high temperature display process is being performed, the processing unit 310 gives priority to protection of the light source 110 and does not display the notification image M5, and does not display the notification image M5. It is preferable to display the notification image M5 only when canceling.

Further, when the information image M is not displayed by the high temperature display process, the processing unit 310 may gradually decrease the luminance of the information image M based on the increase of the temperature T. Further, when displaying the information image M by releasing the high temperature display process, the processing unit 310 may gradually increase the luminance of the information image M based on the decrease in the temperature T. With such a configuration, it is possible to continue the display while reducing the load on the light source 110 in a high temperature environment.

FIG. 8 is a diagram for explaining changes in the information image M based on the passage of time after the temperature T becomes less than the threshold T1, and FIG. 8A shows a state immediately after the temperature T becomes less than the threshold T1 ( FIG. 8B shows a display when the notification image M5 is displayed and the luminance of the information image M3 is gradually increased after the time t1 has elapsed since the temperature T becomes less than the threshold T1. FIG. 8C shows the display when the notification image M5 is not displayed and the information image M3 reaches a desired luminance after the elapse of the time t2 after the time t1. When the processing unit 310 cancels the high temperature display process in which the temperature T is less than the threshold value T1 and displays the information image M (display start), the luminance of the information image M3 is set based on the passage of time as shown in FIG. You may raise it gradually. Further, when the temperature T becomes equal to or higher than the threshold T1 and the high-temperature display process is performed and the information image M is not displayed (display is stopped), the processing unit 310 gradually decreases the luminance of the information image M based on the passage of time. You may let them. With such a configuration, the display can be continued while the driver reduces the load on the light source 110 in a high temperature environment due to the sudden start or stop of the display.

Further, in order to prevent the information image M from switching frequently between display / non-display and the display area A from frequently changing due to the temperature T of the light source 110 straddling the threshold frequently, for example, Hysteresis may be given to the threshold value of the temperature T at which the information image M switches so that the threshold value at which the information image M switches from display to non-display and the threshold value at which the information image M switches from non-display to display.

Further, the light source temperature detection unit (temperature estimation means) 111 may not directly detect the temperature T of the light source 110. The temperature T of the light source 110 may be estimated based on the temperature at a predetermined location in the HUD device 1 by detecting the temperature at a predetermined location in the HUD device 1. Alternatively, the illuminance outside the HUD device 1 may be detected, and based on the external illuminance, it may be estimated that the inside of the HUD device 1 (light source 110) is hot due to sunlight. Alternatively, the temperature T of the light source 110 may be estimated by measuring the value of the current flowing through the light source 110.

DESCRIPTION OF SYMBOLS 1 HUD apparatus (head-up display apparatus) 100 Laser scanning display apparatus 110 Light source 111 Light source temperature detection part (temperature estimation means) 120 Scan part 130 Screen 200 Relay optical system 300 Control part 310 Processing part 320 Storage part 400 Network part 500 Vehicle ECU (image data generation unit) A display area M display image (information image) N number of information images T temperature V virtual image

Claims (9)

A light source that emits laser light;
A scanning unit that generates a display image by scanning a laser beam emitted from the light source;
Temperature estimation means for estimating the temperature of the light source;
A control unit for controlling the light source,
When the control unit determines that the temperature of the light source estimated by the temperature estimation unit is equal to or higher than a predetermined threshold, the controller drives the light source by reducing or / and not displaying at least a part of the display image. Reduce the amount,
A laser scanning display device. The display image is composed of a plurality of information images,
The control unit changes the number of the information images to be displayed according to the temperature of the light source.
The laser scanning display device according to claim 1. The light source comprises a plurality of light sources that emit laser beams of different colors,
The control unit obtains a driving amount for generating the display image for each of the plurality of light sources, and sets an upper limit for the driving amount of the light source when determining that the temperature of the light source is equal to or higher than a predetermined threshold. Reducing the driving amount of the light source so that any of the plurality of light sources does not exceed a set upper limit;
The laser scanning display device according to claim 1 or 2, wherein When the controller reduces or / and increases the driving amount of the light source, the controller notifies that the temperature is high and / or that the driving amount of the laser beam is decreasing or / and increasing. Display an image,
The laser scanning display device according to any one of claims 1 to 3. When the control unit determines that the temperature of the light source has changed from the threshold value to less than the threshold value, the driving amount of the light source is gradually increased.
The laser scanning display device according to claim 1, wherein the laser scanning display device is a laser scanning display device. The control unit gives hysteresis to the threshold value for changing the display image.
6. The laser scanning display device according to claim 1, wherein A laser scanning display device according to any one of claims 1 to 6;
A relay optical system that directs display light indicating the display image generated by the laser scanning display device to a transmission / reflection surface,
A head-up display device. A laser scanning display device according to any one of claims 1 to 6;
A relay optical system for directing display light indicating the display image generated by the laser scanning display device to a transmission / reflection surface;
An illuminance sensor for detecting the illuminance of the outside world,
The controller further reduces the driving amount of the light source when the illuminance becomes larger than a predetermined value.
A head-up display device. A laser scanning display device according to any one of claims 1 to 6;
A relay optical system for directing display light indicating the display image generated by the laser scanning display device to a transmission / reflection surface;
An illuminance sensor for detecting the illuminance of the outside world,
The control unit lowers the threshold when the illuminance is greater than a predetermined value.
A head-up display device.

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