JP7252017B2 - Optical scanning device, control device and vehicle headlight - Google Patents

Description

The present invention relates to an optical scanning device using scanning light from an optical deflector, a control device, and a vehicle headlamp.

A vehicle headlamp equipped with ADB (Adaptive Driving Beam) is known. In such a vehicle headlamp, an area of an oncoming vehicle or a pedestrian in front of the vehicle is set as a mask area (light shielding area) to prevent dazzling of the driver of the oncoming vehicle or the like by the irradiated light.

On the other hand, Patent Document 1 discloses an optical scanning device that irradiates an irradiation range with scanning light from an optical deflector. In order to prevent image distortion in the projected image, the optical scanning device sets a predetermined correction conversion formula, corrects the image data for each pixel using the correction conversion formula, and corrects the image data based on the corrected image data. to control the light source.

JP 2011-87130 A

The size of the light spot of the scanning light emitted from the optical deflector increases or decreases according to the position of the irradiation destination in the irradiation range. In general, the light spot becomes smaller at the center of the irradiation range and elongates as it moves away from the center.

For this reason, a light spot whose center is not located in the mask area irradiates the mask area set at the edge of the irradiation range, and the mask area is originally darkened. It's happening that it's getting brighter.

The optical scanning device of Patent Document 1 simply converts image data according to the shape of the projection surface, etc., and does not deal with the reduction in the light shielding property of the mask region due to the increase in the size of the light spot.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical scanning device, a control device, and a vehicle headlamp capable of coping with dimensional changes in the light spot of scanning light and improving the light shielding properties of the mask region.

The optical scanning device of the present invention is
a light source, an optical deflector that deflects light from the light source to generate scanning light, irradiates an irradiation range with a light spot of the scanning light, and a control device that controls the light source and the optical deflector. An optical scanning device,
The control device is
an information input unit for inputting image information corresponding to an image to be generated in the irradiation range and mask information relating to a mask area within the irradiation range;
an intermediate image data generation unit configured to generate intermediate image data in which the luminance of each of a plurality of pixels forming a screen corresponding to the image of the image information is set based on the image information;
a light spot information holding unit that holds light spot information in which each of a plurality of positions distributed in the irradiation range is associated with the position and the dimension of the light spot centered at the position;
a first pixel determination unit that determines, as a first pixel, a pixel associated with a first light spot whose center is located within the mask region, among the plurality of pixels;
a second pixel determination unit that determines, as a second pixel, a pixel corresponding to a second light spot whose center is located outside the mask region and whose part is located within the mask region, among the plurality of pixels;
a corrected image data generation unit for generating corrected image data in which the brightness of the first pixel is changed to a predetermined brightness or less in the intermediate image data and the brightness of the second pixel is reduced to a value intermediate between the predetermined brightness;
a control unit that controls the light source and the optical deflector based on the corrected image data;
characterized by comprising

According to the optical scanning device of the present invention, corrected image data is generated in which the brightness of the second pixel is reduced to an intermediate value between the predetermined brightness, and the light source and the optical deflector are controlled based on the corrected image data. As a result, irradiation of the mask region by the second light spot is suppressed, so that the light shielding property of the mask region can be improved.

Preferably, in the optical scanning device of the present invention, the corrected image data generating section generates corrected image data in which the brightness of the second pixel is set to the predetermined brightness or less in the intermediate image data.

According to this configuration, the luminance of the second light spot is reduced to the same predetermined luminance as the luminance of the first light spot, so that the light shielding property of the mask region can be further improved.

Preferably, in the optical scanning device of the present invention, the predetermined luminance is a luminance of zero.

According to this configuration, 0 is the predetermined luminance. A light spot corresponding to a brightness of 0 can be generated by turning off the light source. Therefore, control of the light source can be simplified.

Preferably, in the optical scanning device of the present invention, the second pixel determination unit determines the size of the light spot at a position where the information about the size of the light spot is not included in the light spot information. is calculated by an interpolation method from the size of the light spot at the position included in , and the second pixel is determined based on the calculated size.

According to this configuration, even for a light spot at a position where the light spot information does not include information about the size of the light spot, the appropriate size can be calculated and the second pixel can be determined.

Preferably, the optical scanning device of the present invention comprises:
a third pixel determination unit that determines, as a third pixel, a pixel associated with a third light spot that is entirely outside the mask region and partially overlaps the second light spot, among the plurality of pixels; ,
The corrected image data generation unit increases the luminance of the third pixel from the luminance of the intermediate image data to generate the corrected image data.

Although the light-shielding property of the mask region can be improved by reducing the luminance of the second light spot, the brightness of the irradiation region where the center of the second light spot is located is reduced. According to this configuration, corrected image data is generated in which the brightness of the third pixels associated with the third light spot, which is entirely outside the mask region and partially overlaps with the second light spot, is increased. As a result, it is possible to compensate for the brightness of the adjacent area adjacent to the mask area, which has become dark due to the decrease in luminance of the second light spot.

The control device of the present invention is
A control device for generating a control signal for controlling a light source and an optical deflector that deflects light from the light source to generate scanning light and irradiates an irradiation range with a light spot of the scanning light,
an information input unit for inputting image information corresponding to an image to be generated in the irradiation range and mask information relating to a mask area within the irradiation range;
an intermediate image data generation unit configured to generate intermediate image data in which the luminance of each of a plurality of pixels forming a screen corresponding to the image of the image information is set based on the image information;
a light spot information holding unit that holds light spot information in which each of a plurality of positions distributed in the irradiation range is associated with the position and the dimension of the light spot centered at the position;
a first pixel determination unit that determines, as a first pixel, a pixel associated with a first light spot whose center is located within the mask region, among the plurality of pixels;
a second pixel determination unit that determines, as a second pixel, a pixel corresponding to a second light spot whose center is located outside the mask region and whose part is located within the mask region, among the plurality of pixels;
a corrected image data generation unit for generating corrected image data in which the brightness of the first pixel is changed to a predetermined brightness or less in the intermediate image data and the brightness of the second pixel is reduced to a value intermediate between the predetermined brightness;
a control unit that uses a signal generated based on the corrected image data as the control signal;
characterized by comprising

According to the control device of the present invention, the corrected image data is generated by reducing the brightness of the second pixel to an intermediate value between the predetermined brightness, and the light source and the optical deflector are controlled based on the corrected image data. As a result, irradiation of the mask region by the second light spot is suppressed, so that the light shielding property of the mask region can be improved.

A vehicle headlamp according to the present invention includes the optical scanning device.

According to the vehicle headlamp of the present invention, the corrected image data is generated by reducing the luminance of the second pixel to an intermediate value between the predetermined luminance and the light source and the optical deflector are controlled based on the corrected image data. . As a result, irradiation of the mask region by the second light spot is suppressed, so that the light shielding property of the mask region can be improved.

A schematic diagram of a headlight. 3 is a perspective view of an optical deflector; FIG. Detail view of the controller. The front view of an irradiation range. FIG. 4 is a diagram showing the relationship between the position and size of a light spot in an irradiation range; 4 is a graph showing the relationship between the lateral rotation angle of the mirror portion of the optical deflector and the positions of the left end (broken line) and right end (solid line) of the mask area. FIG. 10 is a comparison diagram of the luminance distribution in the mask area when the dimension correction of the light spot is not performed and when it is performed; FIG. 10 is a diagram comparing switching modes of lighting and extinguishing of a light spot when the size correction of the light spot is not performed and when it is performed; The figure which shows the positional relationship of each area|region on an irradiation range. 4 is a flowchart of control with mask position correction performed by the control device; FIG. 2 is a schematic diagram of a headlamp including a plurality of optical scanning devices;

[Vehicle headlight]
FIG. 1 is a schematic diagram of a headlamp 1. FIG. The headlights 1 are provided on the left and right sides of the front part of the vehicle as vehicle headlights. For convenience of explanation, the virtual screen 2 is arranged in FIG. The virtual screen 2 is assumed to stand vertically at a predetermined distance from the headlamp 1 .

The actual irradiation range of the headlight 1 is projected not on the virtual screen 2 but farther than the virtual screen 2 when viewed from the headlight 1. - 特許庁However, even if separate coordinate systems are set for the irradiation range of the virtual screen 2 and the actual irradiation range, the former coordinates and the latter coordinates have a mapping relationship. , the other coordinate is uniquely derived. Note that coordinates are used as a subordinate concept of position, assuming that they are positions defined in a specific coordinate system.

The headlamp 1 includes a control device 4 , a laser light source 5 , a collimator lens 6 , an optical deflector 7 , a correction mirror 8 , a phosphor plate 9 and a projection lens 10 . The control device 4 controls the light intensity of the laser light source 5 and the operation of the mirror portion 31 (FIG. 2) of the optical deflector 7 . The control of the luminous intensity of the laser light source 5 by the control device 4 includes switching between lighting and extinguishing of the laser light source 5 for each pixel, which will be described later.

Emitted light from the laser light source 5 is converted into collimated light La by the collimator lens 6 and enters the optical deflector 7 . The optical deflector 7 reflects the collimated light La incident from the collimator lens 6 by the mirror section 31 (FIG. 2). The mirror unit 31 reciprocates around two axes, reflects the collimated light La, and emits the scanning light Lb that is deflected.

The correction mirror 8 corrects the scanning light Lb from the optical deflector 7 and reflects it toward the phosphor plate 9 as corrected scanning light Lc. The correction of the scanning light Lb by the correction mirror 8 is for coping with the difference in rotational speed around the axis of the mirror section 31 between the center and both ends of the rotational range.

That is, the control device 11 controls the brightness of the laser light source 5 based on the input video information (control of brightness includes switching between lighting and extinguishing of the laser light source 5). However, the reciprocating speed of the optical deflector 7 around the axis of the torsion bar 32 is fast when the torsion bar 32 faces straight ahead, and slow when it faces both ends. In a normal headlamp 1, the rotation speed is controlled so that a light spot with an optimum diameter is generated at the center of the irradiation range, so the light spots generated at both ends of the irradiation range are generated at the center. The dimension in the scanning direction becomes longer than the light spot. This causes distortion of the image produced in the illuminated area. The correction mirror 8 has a role of correcting such image distortion.

The phosphor plate 9 generates white scanning light Ld by wavelength-converting the scanning light Lc with the fluorescent particles. A light distribution pattern as an image is generated on the surface of the phosphor plate 9 on the correction mirror 8 side. The image of the light distribution pattern becomes a scanning image of the scanning light Ld, is incident on the projection lens 10, and further becomes scanning light Le as projection light from the projection lens 10, and is projected onto the virtual screen 2. .

[Optical deflector]
FIG. 2 is a perspective view of the optical deflector 7. FIG. The optical deflector 7 is a biaxial optical deflector of MEMS (Micro Electro Mechanical Systems). For details of the optical deflector 7, see, for example, JP-A-2012-201386, JP-A-2013-8480, and JP-A-2013-84530.

The optical deflector 7 includes a mirror section 31 , a torsion bar 32 , an inner piezoelectric actuator 33 , a movable frame 34 , an outer piezoelectric actuator 35 and a fixed frame 36 . The mirror portion 31 reciprocates about two axes Ax and Ay which are perpendicular to each other at the center.

The torsion bar 32 extends along the axis Ay and connects the mirror section 31 and the movable frame 34 to each other. The inner piezoelectric actuator 33 is interposed between the torsion bar 32 and the movable frame 34, and reciprocates the torsion bar 32 around the axis Ay.

The outer piezoelectric actuator 35 is interposed between the movable frame 34 and the fixed frame 36 , and reciprocates the movable frame 34 around an axis parallel to the long side of the rectangular fixed frame 36 . Thereby, the mirror part 31 reciprocates around the axis Ax.

Reciprocating rotation of the mirror portion 31 about the axis Ay is resonance. Reciprocating rotation of the torsion bar 32 about the axis Ax is non-resonant. The non-resonant frequency is lower than the resonant frequency.

[Control device]
FIG. 3 is a detailed diagram of the control device 11. As shown in FIG. The control device 11 includes a communication section 41 , a light distribution control section 42 , a data storage section 43 , a mask position correction section 44 , an image processing section 45 and a scanning light source control section 46 . The communication unit 41 receives light distribution instruction information from an instruction unit (not shown). The information of the light distribution instruction includes the direction, width, light distribution pattern, and shielding (mask area) of the irradiation range. Information received by the communication unit 41 is output to the light distribution control unit 42 .

Among the information of the light distribution instruction, the light distribution pattern is used synonymously with the light distribution pattern. A video consists of a time series of multiple screens (frames). The light distribution pattern of each screen is a luminance distribution pattern obtained by adding the luminance of each position on the screen. Each position on the screen is also the position of each of a plurality of pixels forming the screen.

The light distribution control unit 42 generates information on a shielding instruction, intermediate image data, and irradiation instruction based on the input from the communication unit 41 and the pixel data from the data storage unit 43 . The light distribution control unit 42 outputs the generated light shielding instruction, intermediate image data, and irradiation instruction information to the mask position correction unit 44, the image processing unit 45, and the scanning light source control unit 46, respectively.

The pixel data is used when the light distribution control unit 42 determines the luminance of each pixel for generating a screen based on the light distribution pattern, and defines the relationship between the designated luminance of the light distribution pattern and the corresponding pixels. Data. The intermediate image data output by the light distribution control unit 42 is data in which the brightness is assigned to each pixel based on the light distribution pattern. Corrected image data is obtained by correcting the intermediate image data using a mask area 51, an interference area 61, a compensation area 62, etc., which will be described later.

The mask position correction unit 44 generates mask instruction information by correcting the luminance of the first, second, and third pixels, which will be described later, based on the light shielding instruction received from the light distribution control unit 42 . The light shielding instruction received by the mask position correcting unit 44 from the light distribution control unit 42 includes the light shielding information received by the light distribution control unit 42 from the communication unit 41 and the mask information received by the light distribution control unit 42 from the data storage unit 43 . included.

The mask position correction unit 44 outputs the generated mask instruction information to the image processing unit 45 . The mask instruction includes information on the first, second and third pixels, which will be described later.

The image processing unit 45 generates corrected image data based on inputs from the light distribution control unit 42 and the mask position correction unit 44 and outputs the corrected image data to the scanning light source control unit 46 . The scanning light source control unit 46 generates a laser control signal and a MEMS control signal based on the corrected image data from the image processing unit 45 in synchronization with the irradiation instruction from the light distribution control unit 42 . A laser control signal and a MEMS control signal are output to the laser light source 5 and the optical deflector 7, respectively.

The laser control signal and the MEMS control signal are synchronized. The laser light source 5 can be turned on and off based on the corrected image data. Turning on and turning off the laser light source 5 correspond to generation and disappearance of a light spot at the irradiation destination of the scanning light Le, respectively. The coordinates of the center of the light spot at the irradiation target are fixed, but the size of the light spot varies according to the coordinates.

FIG. 4 is a front view of the irradiation range 50. FIG. An irradiation range 50 is displayed on the virtual screen 2 . Positions on the illuminated area 50 can be defined by x-axis (horizontal) and y-axis (vertical) coordinates. The origin o is set at the center of the irradiation range 50 (also the center of the virtual screen 2) in this example.

The irradiation range 50 is normally a horizontally long ellipse. H and W are the lengths of the minor and major axes of the illuminated area 50, respectively. Since the headlamp 1 has an ADB (Adaptive Driving Beam) function, a mask area 51 is generated in the irradiation range 50 . A mask area (light shielding area) 51 is set in an area where a person or an oncoming vehicle is located.

FIG. 5 shows the relationship between the position and size of the light spot 54 in the irradiation range 50. As shown in FIG. In FIG. 5, for convenience of explanation, the irradiation range 50 is a horizontally long rectangular range centered on the origin o extracted from the irradiation range 50 in FIG. L, C, and R indicate the left edge, center, and right edge of the irradiation range 50 in the x-axis direction, respectively.

The light spot 54 scans in the x-axis and y-axis directions in the irradiation range 50 . The scanning in the x-axis direction is the direction in which the light spot 54 is scanned by reciprocating the mirror portion 31 around the axis Ay at the resonance frequency in the optical deflector 7 . The scanning in the y-axis direction is the direction in which the light spot 54 is scanned by reciprocating the mirror portion 31 around the axis Ax in the optical deflector 7 at a non-resonant frequency.

The lateral width (dimension in the x-axis direction) of the light spot 54 is small at C in the center in the x-axis direction and long at L and R at both ends. That is, the C light spot 54 has a circular shape, but the L and R light spots 54 have a laterally elongated shape. Although the vertical width of the light spot 54 also changes according to the y-coordinate, it is smaller than the change in the direction of the x-axis.

FIG. 6 is a graph showing the relationship between the lateral rotation angle of the mirror portion 31 of the optical deflector 7 and the positions of the left end (broken line) and right end (solid line) of the light spot 54 . The rotation angle in the horizontal axis direction is the rotation angle of the mirror section 31 around the axis Ay, and the rotation angle when the normal line set at the center of the mirror section 31 faces straight forward is defined as 0°. . With respect to 0°, the rotation angle at which the mirror portion 31 faces right is positive, and the rotation angle at which it faces left is negative.

The horizontal width of the light spot 54 in terms of rotation angle at each horizontal rotation angle of the mirror section 31 corresponds to the difference between the solid line and the wavy line at each horizontal rotation angle of the mirror section 31 . It can be seen from FIG. 6 that the width of the light spot 54 is minimized when the rotation angle is 0°, and increases as the absolute value of the rotation angle increases.

FIG. 7 compares the luminance distribution of the mask region 51 when the mask position correcting unit 44 does not correct the mask position (upper part (a)) and when it does (lower part (b)). FIG. 8 compares how the lighting and extinguishing states of the light spot 54 change when mask position correction is not performed (left side (a)) and when it is performed (right side (b)). there is

Note that the mask position correction by the mask position correction unit 44 is based on the size of the light spot 54, which differs for each position of the light spot 54 in the irradiation range 50, by setting an interference region 61, which will be described later, and not only the mask region 51 but also the mask region 51. This is a correction process for reducing or zeroing the brightness of the light spot 54 centered on the interference region 61 . 7A and 8A correspond to when mask position correction is not performed, and FIGS. 7B and 8B correspond to when mask position correction is performed.

Description will be made from FIG. In FIG. 8, the light spot 54 moves from negative to positive on the x-axis over the irradiation range 50 over time. The left side of the boundary line 59 is outside the mask area 51 and the right side of the boundary line 59 is inside the mask area 51 . The white light spots 54 indicate that they are on, and the hatched light spots 54 indicate that they are off. Also, in each light spot 54 , “x” indicates the center of the light spot 54 .

Here, the first pixel, second pixel and third pixel are defined as follows. In FIG. 8, light spot 541 is the third light spot, light spot 542 is the second light spot, and light spot 543 is the first light spot.

First pixel: Pixel corresponding to light spot 54 (first light spot) whose center x is within mask region 51 Second pixel: Center x is outside mask region 51, but partially within mask region 51 Pixels corresponding to the light spot 54 (second light spot) Third pixel: Pixels corresponding to the light spot 54 (third light spot) which are entirely outside the mask region 51 but partly overlap with the second light spot

In FIG. 7, the mask area 51 is set to be a square with one side of Δx. However, when the light spot 54 approaches L and R in the x-axis direction, the width of the light spot 54 increases. Therefore, when the light spot 54 scans the vicinity of the mask areas 51L and 51R, although the center of the light spot 54 is outside the mask areas 51L and 51R, the edge of the light spot 54 is within the mask area 51L. , 51R.

In the control without mask position correction in FIGS. 7A and 8A, only the light spot 543 (first light spot) is extinguished. As a result, in the mask regions 51L and 51R set to L and R of the mask region 51, the mask regions 51L and 51R are irradiated with the light spot 542 as the second light spot with increased width at the end portions. As a result, both ends in the x-axis direction of the mask regions 51L and 51R become bright.

In FIG. 7(a), ΔxL, ΔxC, and ΔxR are lengths at which the mask regions 51L, 51C, and 51R are completely dark (luminance=0). ΔxL, ΔxC, and ΔxR are all narrower than Δx. However, ΔxL and ΔxR decrease by a larger amount than ΔxC. ΔxL, ΔxC, ΔxR<Δx means that the light shielding properties of the mask regions 51L and 51R are lowered.

In contrast, in the control with mask position correction in FIGS. 7B and 8B, not only the light spot 543 (first light spot) but also the light spot 542 (second light spot) are extinguished. . As a result, in the mask regions 51L and 51R set to L and R of the irradiation range 50, the edge of the light spot 542 (second light spot) with increased width does not irradiate the mask regions 51L and 51R. . As a result, the light shielding properties of the mask regions 51L, 51C and 51R are increased.

Control with mask position correction is also applied to the C mask region 51C in the x-axis direction. Therefore, ΔxL, ΔxC, and ΔxR of the mask regions 51L, 51C, and 51R become the original Δx by control with mask position correction.

FIG. 9 is an explanatory diagram of the mask region 51, the interference region 61, and the compensation region 62 on the irradiation range 50. FIG. The mask area 51 is determined by light shielding information (mask information) included in a light distribution instruction received by the communication section 41 (FIG. 3) from an instruction section (not shown). The mask region 51 is also the region where the center of the first light spot (eg, light spot 543) corresponding to the first pixel is located.

The interference area 61 is set as an area adjacent to the outside of the mask area 51 in the x-axis direction. The interference region 61 is defined as the region where the center of the second light spot (eg, light spot 542) corresponding to the second pixel is located.

The compensation area 62 is set as an area adjacent to the outside of the interference area 61 in the x-axis direction. Compensation region 62 is also defined as the region where the center of the third light spot (eg, light spot 541) corresponding to the third pixel is located.

The mask area 51C is set to the center range C of the irradiation range 50 in the x-axis direction, while the mask area 51L is set to the end range L of the irradiation range 50 in the x-axis direction. Therefore, when the light spot 54 is scanned without turning off, the light spot 54L (FIG. 5) scanning the mask region 51L is wider than the mask region 51C (FIG. 5) scanning the mask region 51C. Therefore, the width of the interference region 61 with respect to the mask region 51L is larger than the width of the interference region 61 with respect to the mask region 51C.

The compensation area 62 is an area where the brightness of the third light spot centered in the compensation area 62 is increased in the corrected image data as compared to the intermediate image data. It is not necessary to increase the brightness of all third pixels. Further, this suppresses an increase in the difference in luminance actually generated by the third light spot on the irradiation destination of the irradiation range 50 with respect to the luminance instructed from the light distribution pattern received by the communication unit 41 .

In the compensation area 62 of FIG. 9, among all the third pixels, only the third pixels included in a predetermined range near the interference area 61 in the x-axis direction are increased in luminance from the luminance of the intermediate image data as the original luminance. ing. Therefore, the compensation area 62 in FIG. 9 has a width narrower than the entire area including the center of the third light spot.

In FIG. 9 , P(x, ys) and P(xe, ye) indicate the coordinates of the upper left and lower right vertices of the mask area 51 . P(x's, y's) and P(x'e, y'e) are defined by the mask region 51 and the interference region 61 sandwiching the mask region 51 from both left and right sides as a first rectangle. , the coordinates of the vertices of the upper left and lower right corners of . P(x''s, y''s) and P(x''e, y''e) are obtained by using the first rectangle and the compensation area 62 sandwiching the first rectangle from both left and right sides as the second rectangle, The coordinates of the vertices of the upper left corner and the lower right corner of the second rectangle are shown. These coordinates are used in the formulas described later.

[Control method]
FIG. 10 is a flowchart of control with mask position correction performed by the control device 4 .

In STEP 101 , the information input unit 21 receives image information corresponding to an image to be generated in the irradiation range 50 and mask information related to the mask area 51 within the irradiation range 50 . The image information and the mask information correspond to the light distribution pattern information and the light shielding information, respectively, included in the light distribution instruction information received by the communication unit 41 in FIG.

In STEP 102, the intermediate image data generation unit 22 generates intermediate image data in which the brightness of each pixel of the screen that is partitioned into a plurality of pixels and displays the image related to the image information is set based on the image information. This processing is performed by the light distribution control unit 42 .

In STEP 103 , the second pixel determining section 25 and the third pixel determining section 26 acquire light spot information from the light spot information holding section 23 . The light spot information refers to each position (eg, xy coordinates in FIG. 4) and the center (eg, x in FIG. 8) for a plurality of positions (eg, xy coordinates in FIG. 4) distributed in the irradiation range 50 is information that associates the size of the light spot 54 at each position (eg, the width of the light spot 54).

The light spot information holding section 23 corresponds to the data storage section 43 (FIG. 3). The first pixel determining section 24 , the second pixel determining section 25 and the third pixel determining section 26 correspond to the mask position correcting section 44 .

In STEP 104, the first pixel determination unit 24 determines the first pixel. The first pixel is a pixel associated with the first light spot (eg, light spot 543 ) whose center is located within the mask region 51 among the plurality of pixels.

In STEP 105, the second pixel determination unit 25 determines second pixels. The second pixel is a pixel corresponding to a second light spot (eg, light spot 542 ) whose center is located outside the mask region 51 and whose part is located inside the mask region 51 among the plurality of pixels.

In STEP 106, the third pixel determination unit 26 determines the third pixel. The third pixel is a pixel associated with a third light spot (eg, light spot 541) that is located entirely outside the mask region 51 and partly located within the interference region 61 among the plurality of pixels. .

The mask position correction unit 44 in FIG. 3 corresponds to the first pixel determination unit 24, the second pixel determination unit 25, and the third pixel determination unit 26. As shown in FIG. Specific processing of the mask position correction unit 44 will be described.

ただし、finterp2は、二次元座標の変換式である。ＬＵＴ_2d－L，ＬＵＴ_2d－U，ＬＵＴ_2d－R，ＬＵＴ_2d－Dは、照射範囲５０上の各座標（ｘ，ｙ）が（ｘｓ，ｙｓ）又は（ｘｅ，ｙｅ）であったときに、該座標（ｘ，ｙ）からそれぞれｘ’ｓ，ｙ’ｓ，ｘ’ｅ，ｙ’ｅを算出するための光スポット情報に含まれている導出関数である。該導出関数は、各座標（ｘ，ｙ）と該座標（ｘ，ｙ）に中心がある光スポット５４の寸法との関係に基づいて設定されている。 The mask position correction unit 44 uses the following equations (1) to (4) to convert the coordinates xs, ys, xe, ye to the coordinates x's, y's, x'e, y'e, x'' Calculate s, y''s, x''e, y''e (FIG. 9).

However, finterp2 is a conversion formula for two-dimensional coordinates. LUT _2d-L , LUT _2d-U , LUT _{2d-R and} LUT _2d-D are calculated when each coordinate (x, y) on the irradiation range 50 is (xs, ys) or (xe, ye) , are derived functions included in the light spot information for calculating x's, y's, x'e, y'e from the coordinates (x, y). The derived function is set based on the relationship between each coordinate (x,y) and the size of the light spot 54 centered at the coordinate (x,y).

ただし、式（５）において、Ｗmax，Ｈmaxは、前照灯１が光偏向器７を使って実現できる照射範囲５０の最大横幅及び最大縦幅を意味する。前照灯１が実際に使用する照射範囲５０の通常のＷ，Ｈは、Ｗ≦Ｗmax，Ｈ≦Ｈmaxとされる。 Next, the mask position correction unit 44 calculates corresponding pixels of the screen associated with (x's, y's) and (x'e, y'e) using the following equation (5). . The screen is partitioned by a plurality of pw×ph pixels arranged in a matrix, and the corresponding screen is displayed by determining the brightness of each pixel.

However, in equation (5), Wmax and Hmax mean the maximum horizontal width and maximum vertical width of the irradiation range 50 that can be realized by the headlamp 1 using the optical deflector 7 . The normal W and H of the illumination range 50 actually used by the headlamp 1 are W≤Wmax and H≤Hmax.

The coordinates P(x''s, y''s) and P(x''e, y''e) of the vertices of the compensation area 62 are calculated by modifying the above equations (1) to (5). can be done. That is, in the above formulas (1) to (5), xs, ys, xe, ye are replaced with x's, y's, x'e, y'e, and x's, y's, x'e , y'e are replaced by x''s, y''s, x''e, y''e.

In STEP 107, the corrected image data generating unit 27 changes the brightness of the first pixel (eg, light spot 543) to 0 in the intermediate image data, and reduces the brightness of the second pixel (eg, light spot 542) to 0 or lower. Generate corrected image data. In the corrected image data, the corrected image data generator 27 also increases the brightness of the third pixel (eg, light spot 543) in the intermediate image data.

In STEP 107, the control section 28 outputs a control signal based on the corrected image data. The control signal is output to the laser light source 5 and the optical deflector 7 . As a result, the decrease in brightness of the interference region 61 is compensated for by the increase in brightness of the compensation region 62, while the light shielding property of the mask region 51 is improved.

[Other embodiments]
FIG. 11 is a schematic diagram of a headlamp 65 having a plurality (eg, four) of optical scanners 66a to 66d. Elements of the vehicle headlamp 65 that overlap with the elements of the headlamp 1 in FIG. The optical scanners 66a to 66d share the correction mirror 8 and elements on the exit side thereof.

The irradiation ranges of the optical scanning devices 66a to 66d are generated on the common virtual screen 2, but the position and size of each irradiation range on the virtual screen 2 are independently controlled in each of the optical scanning devices 66a to 66d. be. The headlight 65 as a whole uses a plurality of light scanning devices 66a-66d to produce an integrated illumination range in front of the vehicle.

The optical scanning devices 66a to 66d are collectively referred to as the optical scanning device 66 when they are not individually distinguished.

The irradiation ranges of the plurality of optical scanning devices 66 may partially overlap on the virtual screen 2, or the irradiation range of one optical scanning device 66 may be completely included in the irradiation range of the other optical scanning device 66. It may be It is a matter of course that the area where the irradiation ranges of the plurality of optical scanning devices 66 overlap has a higher illuminance than the area where they do not overlap. Thereby, the maximum illuminance in the irradiation range can be increased.

In the headlamp 65 , the mask position corrector 44 ( FIG. 3 ) individually generates mask instruction information (corrected image data) for the optical scanning device 66 . Then, the scanning light source control section 46 (FIG. 3) separately outputs the laser control signal and the MEMS control signal to the optical scanning device 66 .

[Modification]
In the embodiment, the brightness of the first pixel associated with the first light spot centered on the mask region 51 is set to 0, and the orientation of the mirror section 31 of the optical deflector 7 is set to generate the first light spot. Then, the laser light source 5 is turned off to make the first light spot completely dark. In the present invention, the luminance of the first pixel can be set to a predetermined luminance or less including luminance=0 without setting the luminance to 0. The predetermined brightness is set to a value that is assumed not to dazzle the driver of an oncoming vehicle or the like existing in the mask area 51 .

When the luminance of the first pixel is set equal to or less than the predetermined luminance, the luminance of the second pixel can be an intermediate value between the luminance of the second pixel in the intermediate image data and the predetermined luminance.

The light spot information held by the light spot information holding unit 23 is expressed by formulas 1 to 5 according to the dimensions of the light spot centered on P(x, y) on the irradiation range 50 (eg, width and height). It contains information about the values of P(xs,ys) and P(xe,ye) corresponding to P(xs,ys) and P(xe,ye). However, the light spot information does not cover the dimension information of the light spots of all coordinates on the irradiation range 50 . If P(xs, ys) or P(xe, ye) is a coordinate P(x, y) not covered by the light spot information, an interpolation method is used to obtain the coordinate P(x, y) Determine the dimensions of the light spot 54 centered at and determine P(x's, y's) and P(x'e, y'e).

A laser light source 5 is used as a light source in the headlights 1 and 65 . In the present invention, an LED (light emitting diode) can also be used as the light source.

In the explanation of FIG. 9, the interference area 61 and the compensation area 62 are set only in the width direction of the mask area 51 . Since the size of the light spot 54 also varies depending on the position in the vertical direction (y-axis direction), it is possible to set the interference region 61 that surrounds the mask region 51 in both the horizontal and vertical directions. Furthermore, the compensation area 62 can also be set so as to surround the interference area 61 from both the horizontal direction and the vertical direction.

DESCRIPTION OF SYMBOLS 1, 65... Headlight (vehicle headlight), 4... Control device, 5... Laser light source (light source), 7... Optical deflector, 21... Information input unit, 22... Intermediate image data generator, 23... Light spot information storage unit, 24... First pixel determination unit, 25... Second pixel determination unit, 26... Third pixel determination unit, 27 Corrected image data generator 28 Control unit 31 Mirror unit 50 Irradiation range 51 Mask area 54 Light spot 61 Interference Area 62 Compensation area 66 Optical scanning device.

Claims (8)

a light source, an optical deflector that deflects light from the light source to generate scanning light, irradiates an irradiation range with a light spot of the scanning light, and a control device that controls the light source and the optical deflector. An optical scanning device,
The control device is
an information input unit for inputting image information corresponding to an image to be generated in the irradiation range and mask information relating to a mask area within the irradiation range;
an intermediate image data generation unit configured to generate intermediate image data in which the luminance of each of a plurality of pixels forming a screen corresponding to the image of the image information is set based on the image information;
a light spot information holding unit that holds light spot information in which each of a plurality of positions distributed in the irradiation range is associated with the position and the dimension of the light spot centered at the position;
a first pixel determination unit that determines, as a first pixel, a pixel associated with a first light spot whose center is located within the mask region, among the plurality of pixels;
a second pixel determination unit that determines, as a second pixel, a pixel corresponding to a second light spot whose center is located outside the mask region and whose part is located within the mask region, among the plurality of pixels;
In the intermediate image data, the luminance of the first pixel is changed to a predetermined luminance or less , and the luminance of the second pixel is reduced to an intermediate value between the luminance of the second pixel in the intermediate image data and the predetermined luminance. a corrected image data generation unit that generates corrected image data;
a control unit that controls the light source and the optical deflector based on the corrected image data;
An optical scanning device comprising: a light source, an optical deflector that deflects light from the light source to generate scanning light, irradiates an irradiation range with a light spot of the scanning light, and a control device that controls the light source and the optical deflector. An optical scanning device,
The control device is
an information input unit for inputting image information corresponding to an image to be generated in the irradiation range and mask information relating to a mask area within the irradiation range;
an intermediate image data generation unit configured to generate intermediate image data in which the luminance of each of a plurality of pixels forming a screen corresponding to the image of the image information is set based on the image information;
a light spot information holding unit that holds light spot information in which each of a plurality of positions distributed in the irradiation range is associated with the position and the dimension of the light spot centered at the position;
a first pixel determination unit that determines, as a first pixel, a pixel associated with a first light spot whose center is located within the mask region, among the plurality of pixels;
a second pixel determination unit that determines, as a second pixel, a pixel corresponding to a second light spot whose center is located outside the mask region and whose part is located within the mask region, among the plurality of pixels;
a corrected image data generation unit that changes the luminance of the first pixel in the intermediate image data to a predetermined luminance or less and generates corrected image data with the luminance of the second pixel set to the predetermined luminance ;
a control unit that controls the light source and the optical deflector based on the corrected image data;
An optical scanning device comprising: The optical scanning device according to claim 2 , wherein
The optical scanning device, wherein the predetermined luminance is a luminance of 0. The optical scanning device according to any one of claims 1 to 3,
The second pixel determination unit determines the size of the light spot at the position included in the light spot information, regarding the size of the light spot at the position where information about the size of the light spot is not included in the light spot information. , and the second pixel is determined based on the calculated dimension. The optical scanning device according to any one of claims 1 to 4,
a third pixel determination unit that determines, as a third pixel, a pixel associated with a third light spot that is entirely outside the mask region and partially overlaps the second light spot, among the plurality of pixels; ,
The optical scanning device, wherein the corrected image data generating section increases the luminance of the third pixel from the luminance of the intermediate image data to generate the corrected image data. A control device for generating a control signal for controlling a light source and an optical deflector that deflects light from the light source to generate scanning light and irradiates an irradiation range with a light spot of the scanning light,
an information input unit for inputting image information corresponding to an image to be generated in the irradiation range and mask information relating to a mask area within the irradiation range;
an intermediate image data generation unit configured to generate intermediate image data in which the luminance of each of a plurality of pixels forming a screen corresponding to the image of the image information is set based on the image information;
a light spot information holding unit that holds light spot information in which each of a plurality of positions distributed in the irradiation range is associated with the position and the dimension of the light spot centered at the position;
a first pixel determination unit that determines, as a first pixel, a pixel associated with a first light spot whose center is located within the mask region, among the plurality of pixels;
a second pixel determination unit that determines, as a second pixel, a pixel corresponding to a second light spot whose center is located outside the mask region and whose part is located within the mask region, among the plurality of pixels;
In the intermediate image data, the luminance of the first pixel is changed to a predetermined luminance or less , and the luminance of the second pixel is reduced to an intermediate value between the luminance of the second pixel in the intermediate image data and the predetermined luminance. a corrected image data generation unit that generates corrected image data;
a control unit that uses a signal generated based on the corrected image data as the control signal;
A control device comprising: A control device for generating a control signal for controlling a light source and an optical deflector that deflects light from the light source to generate scanning light and irradiates an irradiation range with a light spot of the scanning light,
an information input unit for inputting image information corresponding to an image to be generated in the irradiation range and mask information relating to a mask area within the irradiation range;
an intermediate image data generation unit configured to generate intermediate image data in which the luminance of each of a plurality of pixels forming a screen corresponding to the image of the image information is set based on the image information;
a light spot information holding unit that holds light spot information in which each of a plurality of positions distributed in the irradiation range is associated with the position and the dimension of the light spot centered at the position;
a first pixel determination unit that determines, as a first pixel, a pixel associated with a first light spot whose center is located within the mask region, among the plurality of pixels;
a second pixel determination unit that determines, as a second pixel, a pixel corresponding to a second light spot whose center is located outside the mask region and whose part is located within the mask region, among the plurality of pixels;
changing the luminance of the first pixel in the intermediate image data to a predetermined luminance or less; changing the luminance of the first pixel in the intermediate image data to a predetermined luminance or less; and setting the luminance of the second pixel to the predetermined luminance. a corrected image data generating unit for generating corrected image data;
a control unit that uses a signal generated based on the corrected image data as the control signal;
A control device comprising: A vehicle headlamp comprising the optical scanning device according to any one of claims 1 to 5.

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