JP6798404B2 - Projector, projection method and program - Google Patents

Description

The present invention relates to a device that projects light from a light source.

A device that displays an image by scanning a laser beam is known. For example, Patent Document 1 discloses a laser display device that blocks or stops the projection of laser light to the outside when a failure of a scanner that scans laser light is detected.

Further, Patent Document 2 includes a scanning means for scanning a plurality of laser beams in different emission directions emitted from the light source device toward the projected surface, and a housing for accommodating the light source device and the scanning means for scanning. An image display device in which a light source device and scanning means are arranged so that a laser beam is not emitted to the outside of a housing when the means fails and stops in a balanced state is disclosed.

Japanese Patent No. 4407179 Japanese Patent No. 4736993

In both of the methods of Patent Documents 1 and 2, when the scanning means fails, the laser light is prevented from being emitted to the outside of the apparatus, so that the amount of laser light irradiation to the outside is determined by the laser class to which the product belongs. It does not exceed the dose given. However, in the method of the above document, no image is displayed in the normal image display area, so that the user should display whether the display device has some trouble, the display device is in the OFF state, or the display device is in the OFF state. It is not possible to quickly recognize whether there is only an image.

As an example of the problem to be solved by the present invention, the above is given as an example. An object of the present invention is to provide a projection device capable of promptly making a user recognize the occurrence of a failure when a failure occurs in the scanning unit.

The invention according to claim 1 is a projection device, which comprises a light source that emits a laser beam, a scanning means that scans the laser beam within a display area, a failure detecting means that detects a failure of the scanning means, and a failure detecting means.
A control means for causing the light source to emit a predetermined light when a failure is detected by the failure detection means .
Equipped with an external environment detection means that detects the brightness of the external environment
When a failure is detected by the failure detecting means, the control means causes the light source to emit light at a predetermined light amount or less, and the predetermined light amount is determined according to the brightness of the external environment detected by the external environment detecting means. It is characterized by changing .

An example of a head-up display to which the projection device of the embodiment is applied is shown. It is a block diagram which shows the internal structure of a projection apparatus. It is a figure which shows the structural example of the MEMS mirror. A display example at the time of failure of the MEMS mirror is shown. It is a flowchart of the failure display process of the MEMS mirror.

In one preferred embodiment of the present invention, the projection device comprises a light source that emits a laser beam, scanning means that scans the laser beam into a display region, and a failure detecting means that detects a failure of the scanning means. A control means for causing the light source to emit a predetermined light when a failure is detected by the failure detecting means.

The projection device scans the laser beam from the light source into the display area by the scanning means. Further, a failure detecting means for detecting a failure of the scanning means is provided, and when a failure of the scanning means is detected, the light source emits a predetermined light. The predetermined light emission functions as a failure indicator, and the user can easily recognize the occurrence of the failure by seeing the predetermined light emission.

In one aspect of the projection device, the control means causes the light source to emit light at a predetermined amount of light or less when a failure is detected by the failure detecting means. In this aspect, when a failure occurs in the scanning means, light is emitted at a predetermined light amount or less so as not to exceed the irradiation amount specified in the laser class.

In another aspect of the projection device, the scanning means scans the laser beam by swinging in response to a supplied drive signal, and the control means detects a failure by the failure detecting means. In that case, the supply of the drive signal to the scanning means is stopped. In this aspect, since the supply of the drive signal is stopped when the scanning means fails, a predetermined light emission is performed at a predetermined position within the display range of the laser beam.

In another aspect of the projection device, the control means blinks the light source when a failure is detected by the failure detecting means. In this aspect, since the light source blinks and emits light, the user can easily notice the occurrence of the failure.

In another aspect of the projection device, the external environment detecting means for detecting the brightness of the external environment is provided, and the control means is provided by the external environment detecting means when a failure is detected by the failure detecting means. The predetermined amount of light is changed according to the detected brightness of the external environment. In this aspect, in consideration of the brightness of the external environment, a predetermined amount of light is emitted with an amount of light that is easy for the user to see.

In another aspect of the projection device, the control means causes the light source to emit a laser beam of a predetermined color when a failure is detected by the failure detecting means. In this aspect, the occurrence of a failure can be clearly indicated to the user by emitting a laser beam of a predetermined color indicating the occurrence of the failure.

In another preferred embodiment of the present invention, a projection method performed by a projection apparatus comprising a light source that emits a laser beam and a scanning means that scans the laser beam is such that the scanning means emits the laser beam. The present invention includes a scanning step of scanning within the display area, a failure detection step of detecting a failure of the scanning means, and a control step of causing the light source to emit a predetermined light when a failure is detected by the failure detection step. .. The user can easily recognize the occurrence of a failure by seeing a predetermined light emission.

In another preferred embodiment of the present invention, a program executed by a projection device comprising a light source that emits laser light, a computer, is a scanning means that scans the laser light into a display area, the scanning means. The computer functions as a failure detecting means for detecting a failure and a control means for causing the light source to emit a predetermined light when a failure is detected by the failure detecting means. The above projection device can be realized by executing this program on a computer. This program can be stored and handled in a storage medium.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[Device configuration]
(Head-up display)
First, an example of a head-up display (hereinafter, referred to as “HUD”) to which the projection device according to the embodiment is applied will be described. FIG. 1 shows a schematic configuration of the HUD 40. As shown in FIG. 1, the HUD 40 is attached to a vehicle including a light source unit 41, a front window 46, a ceiling 47, a bonnet 48, a dashboard 49, and the like.

The light source unit 41 is installed on the ceiling portion 47 in the vehicle interior via the support members 43a and 43b, and emits light that constitutes an image showing information that assists driving toward the combiner 44. Specifically, the light source unit 41 generates an original image (real image) of the display image in the light source unit 41 by the internal projection device 42, and emits the light constituting the image to the combiner 44 to generate the combiner 44. The driver is made to visually recognize the virtual image Iv through.

The combiner 44 projects the display image emitted from the light source unit 41 and reflects the display image to the driver's eye point Pe to display the display image as a virtual image Iv. Then, the combiner 44 has a support shaft portion 45 installed on the ceiling portion 47, and rotates around the support shaft portion 45 as a support shaft. The support shaft portion 45 is installed, for example, in the vicinity of the ceiling portion 47 near the upper end of the front window 46, in other words, the position where the sun visor (not shown) for the driver is installed. The support shaft portion 45 may be installed in place of the above-mentioned sun visor.

(Projection device)
Next, the projection device 42 will be described. FIG. 2 shows the configuration of the projection device 42. As shown in FIG. 2, the projection device 42 includes an image signal input unit 2, a video processing unit 3, a frame memory 4, a ROM 5, a RAM 6, a laser driver 7, and a MEMS (Micro Electro Mechanical Systems) driver 8. A laser light source unit 9 having a MEMS mirror 95, a microlens array 13, a field lens 14, a timing controller 21, and an MCU (Micro Controller Unit) 22 are provided. The projection device 42 is used in the HUD 40 and emits light forming a display image to the combiner 44.

The image signal input unit 2 receives the image signal Si input from the outside and outputs it to the image processing unit 3. The image processing unit 3 writes the image data input from the image signal input unit 2 to the internal frame memory, reads it out at any time according to the drive timing of the MEMS mirror 95, and reads red (R), green (G), and blue (B). ), The control signals corresponding to the brightness of each pixel are sequentially transmitted to the laser driver 7.

The timing controller 21 controls the timing of reading the image data from the frame memory of the video processing unit 3. The timing controller 21 also controls the operation timing of the MEMS driver 8 based on the scanning position information Sc output from the MEMS mirror 95.

The ROM 5 stores a control program, data, and the like for operating the video processing unit 3. Various data are sequentially read and written to the RAM 6 as a work memory when the video processing unit 3 operates.

The laser driver 7 is a block that generates a signal for driving a laser diode provided in the laser light source unit 9 described later. The laser driver 7 includes a red laser drive circuit 71, a blue laser drive circuit 72, and a green laser drive circuit 73.

The red laser drive circuit 71 drives the red laser element LD1 based on the control signal output by the image processing unit 3. The blue laser drive circuit 72 drives the blue laser element LD2 based on the control signal output by the image processing unit 3. The green laser drive circuit 73 drives the green laser element LD3 based on the signal output by the image processing unit 3.

The MEMS driver 8 controls the MEMS mirror 95 based on the signal output by the timing controller 21. The MEMS driver 8 includes a servo circuit and a driver circuit. The servo circuit controls the operation of the MEMS mirror 95 based on the signal from the timing controller 21. The driver circuit amplifies the control signal of the MEMS mirror 95 output by the servo circuit to a predetermined level and outputs it.

The laser light source unit 9 emits laser light based on the drive signal output from the laser driver 7. Specifically, the laser light source unit 9 includes a red laser element LD1, a blue laser element LD2, a green laser element LD3, collimator lenses 91a to 91c, reflection mirrors 92a to 92c, and a light receiving unit 24. ..

The red laser element LD1 emits a red laser beam (also referred to as “red laser beam Lr”), and the blue laser element LD2 emits a blue laser beam (also referred to as “blue laser beam Lb”) to emit a green laser. The element LD3 emits a green laser beam (also referred to as “green laser beam Lg”). The collimator lenses 91a to 91c make the red, blue, and green laser beams Lr, Lb, and Lg parallel light, and emit the red, blue, and green laser beams to the reflection mirrors 92a to 92c, respectively. The reflection mirror 92b reflects the blue laser light Lb. The reflection mirror 92c transmits the blue laser light Lb and reflects the green laser light Lg. The reflection mirror 92a reflects a part of the red laser beam Lr and transmits the rest. Further, the reflection mirror 92a transmits a part of the blue and green laser beams Lb and Lg and reflects the remaining part. The red laser beam Lr transmitted through the reflection mirror 92a and the blue and green laser beams Lb and Lg reflected by the reflection mirror 92a are incident on the MEMS mirror 95. Further, a part of the red laser light Lr, the blue laser light Lb, and the green laser light Lb is applied to the light receiving unit 24.

A microlens array 13 and a field lens 14 are provided at positions where laser light is emitted from the laser light source unit 9. The MEMS mirror 95 reflects the laser beam incident from the reflection mirror 92a toward the microlens array 13 which is an example of the EPE (Exit Purple Explorer). The MEMS mirror 95 basically scans on the microlens array 13 under the control of the MEMS driver 8 in order to display an image (hereinafter, referred to as “input image”) input to the image signal input unit 2. The scanning position information (for example, information such as the angle of the mirror) at that time is output to the timing controller 21 as scanning position information Sc.

A plurality of microlenses are arranged in the microlens array 13, and the laser beam reflected by the MEMS mirror 95 is incident on the microlens array 13. The field lens 14 magnifies an image formed on the radial surface of the microlens array 13 and projects it on a projection surface (not shown). For example, when the projection device 42 is used as a light source for a head-up display, the field lens 14 emits light that constitutes a display image to a combiner or the like.

The light receiving unit 24 is composed of a photodetector, receives the combined light of the red laser light Lr, the blue laser light Lb, and the green laser light Lb, and outputs a signal Sd indicating a voltage corresponding to the intensity of the combined light to the MCU 22. .. The MCU 22 controls the light emission and stop of each of the laser light sources LD1 to LD3 by the laser driver 7 based on the voltage value output from the light receiving unit 24.

(MEMS mirror)
Next, the configuration of the MEMS mirror 95 will be described. FIG. 3 is a top view of the MEMS mirror 95. As shown in FIG. 3, the MEMS mirror 95 mainly includes a fixed frame 31, a frame portion 32, a mirror portion 33, magnets 34A to 34D, X-axis torsion bars 35A and 35B, and a Y-axis torsion bar 36A. , 36B and strain gauges 37V, 37H.

The fixed frame 31 is a structure for supporting the frame portion 32, and is formed of a metal material or a semiconductor material such as silicon. The fixed frame 31 has a frame shape having a gap inside. The frame portion 32 has a frame shape having a gap inside. The frame portion 32 is connected to the fixed frame 31 via the X-axis torsion bars 35A and 35B, and can swing (rotate) with respect to the fixed frame 31 with the X-axis torsion bars 35A and 35B as rotation axes. ..

A convex pattern is formed on the surfaces of the fixed frame 31 and the frame portion 32, and the wiring pattern extending from the fixed frame 31 via the X-axis torsion bars 35A and 35B follows the frame shape of the frame portion 32. A coil 38 is formed on the surface of the frame portion 32. The mirror portion 33 is a disk-shaped member having a reflective film for reflecting incident light formed on its surface, and is connected to the frame portion 32 via Y-axis torsion bars 36A and 36B. The mirror portion 33 is swingable with respect to the frame portion 32 with the Y-axis torsion bars 36A and 36B as rotation axes. The magnets 34A to 34D are arranged around the frame portion 32, and generate magnetic fields in the horizontal (H) direction and the vertical (V) direction in the region where the coil 38 formed in the frame portion 32 exists.

A strain gauge 37V is provided near the X-axis torsion bar 35B, and a strain gauge 37H is provided near the Y-axis torsion bar 36B. The strain gauge 37V is a sensor that detects the position of the mirror portion 33 in the vertical (V) direction, and outputs a voltage corresponding to the twist amount and the twist direction of the X-axis torsion bar 35B. The strain gauge 37H is a sensor that detects the position of the mirror portion 33 in the horizontal (H) direction, and outputs a voltage corresponding to the twist amount and the twist direction of the Y-axis torsion bar 36B.

As described above, in the MEMS mirror 95, the mirror portion 33 is rotatably connected to the fixed frame 31 by the X-axis torsion bars 35A and 35B and the Y-axis torsion bars 36A and 36B. The mirror unit 33 rotates due to the action of an electromagnetic force generated by the drive signal input from the MEMS driver 8 flowing through the coil 38. When no drive signal is input, the mirror unit 33 comes to rest at a position where the X-axis torsion bar 35 and the Y-axis torsion bar 36 are in an equilibrium state, that is, a neutral position. The rotational displacement of the MEMS mirror 95 is calculated based on the outputs of the strain gauges 37V and 37H, and is output to the timing controller 21 as scanning position information Sc indicating the scanning position of the laser beam.
[Failure display control]
Next, the failure display control in this embodiment will be described. As described above, the timing controller 21 controls the MEMS driver 8 to supply the drive signal to the MEMS mirror 95, and monitors the rotational displacement of the MEMS mirror 95 based on the scanning position information Sc output from the MEMS mirror 95. To do. Here, when the MEMS mirror 95 fails for some reason and the rotational displacement corresponding to the input drive signal cannot be obtained, the timing controller 21 outputs the error signal Se to the MCU 22 and drives the MEMS mirror 95. Stop the signal supply. As a result, the mirror portion 33 of the MEMS mirror 95 stops at a position where the X-axis torsion bar 35 and the Y-axis torsion bar 36 are in an equilibrium state, that is, a neutral position.

When the MCU 22 receives the error signal Se, it controls the laser driver 7 and causes only the red laser element LD1 to emit light with a predetermined brightness. The brightness in this case is set to a brightness that does not exceed the irradiation amount defined by the laser class. Specifically, the MCU 22 controls the red laser light Lr so as to have the above-mentioned predetermined brightness with reference to the signal Sd output from the light receiving unit 24. At this time, preferably, the red laser beam Lr is blinked so that the user (driver) can easily notice it.

At this time, as described above, the supply of the drive signal to the MEMS mirror 95 is stopped, and the MEMS mirror 95 is stopped at the neutral position. Therefore, the emission of the red laser beam LD1 is emitted by the MEMS as illustrated in FIG. It is displayed as a red bright spot 50 near the center of the normal scanning area of the mirror 95, that is, the image display area. In this way, the red bright spot is displayed as a failure indicator. In this way, when a failure occurs in the MEMS mirror 95, a red bright spot is displayed in the normal image display area, so that the user can quickly recognize the occurrence of the failure.

FIG. 5 is a flowchart of failure display control of the MEMS mirror. This process is realized by the MCU 22 executing a program prepared in advance. First, the MCU 22 determines whether or not the MEMS mirror 95 has a failure (step S1). Specifically, the MCU 22 determines that the MEMS mirror 95 has a failure when receiving the above-mentioned error signal from the timing controller 21, and sets the MEMS mirror to 95 when the error signal is not received. It is determined that no failure has occurred.

If no failure has occurred (step S1: No), the process ends. On the other hand, when a failure has occurred (step S1: Yes), the MCU 22 controls the timing controller 21 to stop the supply of the drive signal from the MEMS driver 8 to the MEMS mirror 95 (step S2). Further, the MCU 22 controls the laser driver 7 and emits a predetermined light as a failure indicator as described above (step S3). And the process ends.

[Modification example]
Next, a modification of the above embodiment will be described. The following modifications can be applied in combination as appropriate.

(Modification example 1)
In the above embodiment, the red bright spot or the blinking red bright spot is displayed as the failure indicator, but the application of the present invention is not limited to this. For example, a color other than red may be displayed or another color may be blinked. Further, for example, different colors such as red → green → blue may be repeatedly displayed.

(Modification 2)
An external light sensor may be provided to detect the brightness of the surrounding environment, and the brightness of the bright spot displayed as a failure indicator may be changed according to the brightness of the surrounding environment. Specifically, the external light sensor is connected to the MCU 22, and the output of the external light sensor is supplied to the MCU 22. The MCU 22 changes the brightness of bright spots such as red according to the amount of external light. That is, when the surrounding environment is bright, the bright spots are brightened accordingly, and when the surrounding environment is dark, the bright spots are darkened accordingly. This makes it possible to display the failure indicator with a brightness suitable for the brightness of the surrounding environment.

7 Laser driver 8 MEMS driver 9 Laser light source section 21 Timing controller 22 MCU
24 Light receiving part 31 Fixed frame 33 Mirror part 35A, 35B X-axis torsion bar 36A, 36B Y-axis torsion bar 40 Head-up display 42 Projector 95 MEMS mirror

Claims (4)

A light source that emits laser light and
A scanning means for scanning the laser beam into the display area, and
A failure detecting means for detecting a failure of the scanning means and
A control means for causing the light source to emit a predetermined light when a failure is detected by the failure detection means.
Equipped with an external environment detection means that detects the brightness of the external environment
When a failure is detected by the failure detecting means, the control means causes the light source to emit light at a predetermined light amount or less, and the predetermined light amount is determined according to the brightness of the external environment detected by the external environment detecting means. A projection device characterized by changing. The scanning means scans the laser beam by swinging in response to a supplied drive signal.
The projection device according to claim 1 , wherein the control means stops the supply of the drive signal to the scanning means when a failure is detected by the failure detecting means. The projection device according to any one of claims 1 or 2 , wherein the control means blinks the light source when a failure is detected by the failure detection means. The projection device according to any one of claims 1 to 3 , wherein the control means causes the light source to emit a laser beam of a predetermined color when a failure is detected by the failure detection means.