JPH0222329B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting the optical axis of an automobile headlamp.

[Conventional technology]

In order to ensure forward visibility and avoid dazzling oncoming vehicles, automobile headlights are regulated in terms of direction, up and down, left and right, and must be properly adjusted and installed within these limits. It won't happen.

As an example, as shown in Figure 1, the current headlight tester that inspects the irradiation direction of headlights uses two pairs of light-receiving elements, upper and lower and left and right. This method involves finding a point where the luminous intensity of the pair is balanced, and detecting the optical axis, which is the axis of the irradiation direction. In the figure, HL is a headlamp, T is a headlight tester, Ja and Jb are a pair of left and right balance detection sensors, and Ka and Kb are a pair of vertical balance detection sensors.

[Problem to be solved by the invention]

However, with this method, JIS and
It is possible to detect the optical axis of a headlight that has a light distribution pattern like a running beam regulated by SAE, but it is possible to detect the optical axis of a headlight that has a light distribution pattern like a driving beam regulated by SAE, but it is also possible to detect a passing beam of a headlight according to JIS or SAE standards or a mismatch of headlights according to European standards. It cannot be used in cases such as beams.

However, in recent years, from the standpoint of improving safety and frequency of use, headlights have been designed that emphasize passing beams more than driving beams, and at the same time, optical axis adjustment (aiming) when installing headlights has become more important. is becoming more important. Additionally, headlights are required to be able to see obstacles 10 meters ahead.
In JIS, headlights are regulated by a light distribution pattern projected on a screen 100 meters in front of the vehicle. Therefore, headlights are designed to meet this condition.

By the way, since a headlamp is not a point light source but a surface light source with a certain area, it is avoided that the light distribution pattern projected on the screen differs depending on the distance from the headlamp, especially at short distances. I can't. However, the current headlight tester is a method that measures at a relatively short distance (3 meters) from the headlight due to the fact that it is practically difficult to widely install measurement equipment in a vehicle inspection area. Therefore, the change in light distribution caused by this difference in distance, that is, the difference between 3 meters and 10 meters, is a value that cannot be ignored.

Furthermore, the direction of irradiation of headlights is determined by human visual perception, and current headlights and
Since the tester physically measures the amount of light,
This may end up measuring parts, ranges, contrast, etc. that cannot be perceived by humans, which may lead to results that are contrary to the purpose of the measurement.

[Means to solve the problem]

In order to solve such problems, the applicant of the present invention has recently developed a method for reducing the light distribution pattern of automobile headlights by using a condensing lens to create a reduced light distribution pattern. As a means of collecting light intensity data from the light pattern, by moving a light sensor array in which a plurality of light intensity sensors are arranged at regular intervals on a straight line, a large number of light intensity data can be collected over the entire surface of the reduced light distribution pattern. We are proposing a device that measures the amount of light at a point.

The present invention relates to this type of device, in which a rectangular
The present invention provides an optical axis detection device for an automobile that can collect light amount data in ABCD in an orderly manner and can instantly collect light amounts of light amount sensors s ₁ to s _n . The translucent portions and the non-transparent portions are arranged alternately, and a wide section is provided at both ends thereof, the width being wider than the width of the translucent portion and the non-transparent portion, and one and the other of the wide sections are arranged as the translucent portion. and a position mark plate added as a non-transparent part, which is arranged so that its center coincides with the central axis of the optical sensor array, and moves simultaneously with the optical sensor array, and as it moves, the position mark plate becomes transparent. A position detection sensor that detects the width of the light-transmitting part and the non-light-transmitting part as its output signal width, and a position mark board transparency that is detected as an edge change from one side to the other side of the output signal of this position detection sensor. The amount of light is collected by an array of optical sensors at each boundary between the light-transmitting part and the non-light-transmitting part, and the starting point and end point for moving the optical sensor array are detected based on the width of the output signal of the position detection sensor. It was designed to be carried out at

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, in order to facilitate understanding of the present invention, means for reducing the 10 meter light distribution pattern to a short distance will be explained with reference to FIG. In the figure, the center of the condensing lens L is placed on the lamp axis O-O' of the headlamp HL, and a virtual screen on which the condensing lens L and the reduced light distribution are reflected relative to the lamp axis O-O'
Screen SC ₁ and SC ₂ with 10 meter light distribution
When installed vertically, if there is no condenser lens L and virtual screen SC ₁ , the headlamp HL
By inserting _the condensing lens L, the light distribution projected on _the screen SC ₂ placed 10 meters from It will be done. At this time, there is a predetermined correlation between the distances b ₁ and b ₂ , the focal length F of the condenser lens L, and the reduction rate m of light distribution, and this can be changed depending on the design specifications. can do. In addition, in the figure, P indicates the center of the condensing lens L.

By collecting light amount data from the reduced light distribution pattern projected in this way, it is possible to
Measurements equivalent to 10 meter light distribution measurements can be made.

When the light distribution pattern of a car headlamp is similarly reduced using a condensing lens, the rotation angle of the headlamp and its axis can be expressed as a distance in a plane perpendicular to the center line of the headlamp. Ru. This will be explained using FIGS. 3a and 3b.

The distance a between the center line of the headlamp HL and a plane orthogonal to it when the condenser lens L is not used, and the distance a between the center line of the headlamp HL and the plane perpendicular to the center line of the headlamp HL when the condenser lens L is not used
The rotation angle of HL is θ, and the condenser lens L is set as shown in Fig. 3a.
If the reduction rate at which rectangle A'B'C'D' is reduced to rectangle ABCD in Figure 3b is m, then vertical line V and horizontal line H
The distance y′ from the intersection with is expressed as y′=matanθ.

Therefore, the distance y when the condenser lens L of FIG. 3a is not used, that is, the rotation angle .theta. of the headlamp, is represented by the distance y' by the condenser lens L of FIG. 3b. Therefore, as shown in Figure 3b, in order to collect the amount of light within the rectangle ABCD of the reduced light distribution pattern in a grid pattern using the array of optical sensors, it is necessary to Find the distance y' (y ₁ , y ₂ ...y _o ) to the center position (see Figure 4) from the above relational expression,
Using a position mark board with a position mark attached at a position corresponding to this distance y' (y ₁ , y ₂ ... y _o ) and a position detection sensor that reads the position mark on this position mark board, the position detected by this position detection sensor is used. The amount of light shall be collected every time a mark is detected.

Next, a method of sampling light quantity data of the reduced light distribution pattern will be explained. First, in order to have wide versatility for various types of light distribution and to realize processing similar to visual sensation, we developed a method that collects light intensity data of reduced light distribution patterns over a wide range and in finely divided manner. Use. The light amount data of the reduced light distribution pattern projected on the virtual screen SC ₁ in FIG. 2 is collected in the following manner.

FIG. 4 is a block diagram showing an embodiment of the means by which the light quantity sensor used in the present invention collects light quantity data from a reduced light distribution pattern, and the means for data sampling of the reduced light distribution pattern by moving the optical sensor array. This is an example. In the figure, H is the horizontal line, V
is a vertical line, and both are the lamp axis and the virtual screen.
Orthogonal on the plane of SC ₁ . Sm is an optical sensor array in which m light quantity sensors s ₁ to s _n are arranged at regular intervals on a straight line, PDS is a position detection sensor,
This position detection sensor PDS is arranged so that its center coincides with the central axis of the optical sensor array Sm, that is, its center coincides with the line connecting the centers of the light quantity sensors s ₁ to s _n . PM is the part through which light passes (transparent part)
PMa and the area where light does not pass through (opaque area)
This is a position mark board that alternates with PMb, and the position mark of this position mark board PM is rectangular ABCD
Each center corresponding to the position is marked.
S _PDS is a signal from the position detection sensor PDS. Also,
The optical sensor array Sm is aligned with the lamp axis O-O' (see Figure 2).
It is arranged in parallel with the vertical line V on the plane of the virtual screen SC ₁ which intersects at right angles with the point O ₁ .

The position mark is constructed as follows. First, a white and black (transparent, opaque) striped pattern is placed on the board so that the position detection sensor PDS can output an ON-OFF signal S _PDS depending on whether light is transmitted or not. In FIG. 4, the hatched portions of the position mark plate PM indicate portions through which light does not pass, and the other portions indicate portions through which light passes.
Therefore, position marks indicating the positions of the respective centers on side AB are defined as boundaries that change from black to white or from white to black. Then, the position detection sensor PDS detects this position mark as an edge change from on (ON) to off (OFF) or from off (OFF) to on (ON). Further, the position mark plate PM has wide sections PM1 and PM2 at both ends thereof, which are wider than the light-transmitting portion PMa and the non-light-transmitting portion PMb,
The colors of the wide sections PM1 and PM2 are contrasted. That is, the wide sections PM1 and PM2 are added to the light-transmitting portion PMa and the light-opaque portion PMb, which are arranged alternately, as a light-transmitting portion and a non-light-transmitting portion. These wide sections PM1 and PM2 are
This is done to determine whether the optical sensor array Sm exists before the starting point or after the ending point. Note that the position mark on the position mark plate PM and the signal S _PDS of the position detection sensor PDS may be captured by reflection of light.

Next, the operation of the embodiment shown in FIG. 4 will be explained. That is, according to this embodiment, when the "white" striped pattern of the position mark plate PM comes to the position detection sensor PDS, and when the "black" ON signal of the position detection sensor PDS signal S _PDS comes, An OFF signal is output. Therefore, assuming that the optical sensor array Sm is moved from A to B on side AB, ON-OFF
Light intensity sensor s ₁ to _{s n} at the rising edge of the signal pulse
If the amount of light is collected instantaneously and then repeated sequentially, m×n pieces of data can be collected.

In addition, the device shown in this embodiment has an optical sensor array Sm
It is possible to move from one position to another by the rotation of the motor that drives it, and by rotating the motor forward and backward, it can move from the start point to the end point, or from the end point to the start point, or continuously reciprocate. The optical sensor Column Sm
When moving from B to A on side AB, the signal S of the position detection sensor _PDS is ON-OFF.
Light intensity sensor s ₁ to _{s n} at the falling edge of the signal pulse
By instantly collecting the amount of light, m×n pieces of data can be collected.

That is, by scanning the optical sensor array Sm to positions ˜n, m×n pieces of light amount data within the rectangle ABCD are sampled. By employing such a sampling method, it is advantageous in terms of cost, accuracy, etc., compared to, for example, the case where the following sampling method is employed. That is, as another sampling method, m×n of the virtual screen SC ₁ in FIG.
A possible method is to sample the light amount data within the rectangle ABCD (see FIG. 4) by fixing m×n individual light amount sensors at different positions in a matrix. However, if such a sampling method is adopted, it is possible to omit the drive unit for moving the optical sensor array Sm, but the output from the light amount sensor (which will be described later) (the current and voltage change depending on the amount of light, i.e. m×n amplifiers are required to amplify the light intensity signal (obtained by photoelectric conversion). In other words, when such a sampling method is adopted, compared to using an array of optical sensors, more light amount sensors are required, and accordingly, more amplifiers are required. On the other hand, the method of moving the optical sensor array is simplified by reducing the number of components such as the light amount sensor and the amplifier, which promotes total cost reduction. Furthermore, since there are fewer light amount sensors, variations in photoelectric conversion characteristics among the light amount sensors are small, and the optical axis detection accuracy, which will be described later, is improved.

In addition, the positions of the boundaries from black to white, which correspond to the respective centers of the position marks on the position mark board PM, are located in the angle and distance relationship determined from Figure 3 a and b, as described above. There is. Furthermore, the central axis of the optical sensor array Sm and the center of the position detection sensor PDS coincide.

Next, the wide section on the position mark board PM
To explain PM1 and PM2, the square shape
In order to collect ABCD data in an orderly manner,
The first stop position of the optical sensor array Sm needs to be on or outside the side AB. To do this, it is necessary to determine the position of the optical sensor array Sm before data collection, and this is done as follows.

First, move the optical sensor array Sm in the direction from side B to side A, and when the pulse width of the signal S _PDS of the position detection sensor PDS, in this case, the OFF time exceeds tb, the position on side AB The drive signal for the optical sensor array Sm is turned OFF as the sensor is outside. In addition, when the optical sensor array Sm moves from A to B on the side AB and stops the optical sensor array Sm after collecting data, the ON time of the signal S _PDS of the position detection sensor PDS is longer than tw. When the position detection sensor PDS
When the number of rising pulses of the signal S _PDS becomes n or more, it is assumed that the optical sensor array Sm is out of position, and the drive signal for the optical sensor array Sm is turned off. Note that the position detection sensor PDS is designed to always move at a constant speed.

Note that the optical sensor array Sm is structured so that it can be moved freely manually except during data sampling, so immediately before data sampling or after turning on the power,
Using the method described above, the optical sensor array Sm is moved outside the position on the side AB and stopped.

Based on the data collected in this way,
Proceed with processing judgment. However, the plane of the virtual screen SC ₁ on which the reduced light distribution pattern shown in FIG. 2 is projected and the horizontal line H and vertical line V shown in FIG. 4 are in the same plane.

FIG. 5 is a perspective view showing the structure of an embodiment of the optical axis detection device for an automobile headlamp according to the present invention. In the figure, 1 is a front panel fixed to a condenser lens 2 (corresponding to condenser lens L in Fig. 2) that condenses the light from the headlamp HL, and 3 is a front panel that is approximately 45mm along the optical axis of the condenser lens 2. A half mirror 4 is installed at an angle of 45 degrees to the optical axis of the half mirror 3, and each of the half mirrors 3 and 4 can be adjusted freely on a mirror mount 5 via a spring (not shown). configured to be retained. 6 is a display panel, and this display panel 6 includes a light distribution measurement start switch (S/SW) 7 and a switch (RL/SW) for informing a separate microcomputer of the left and right sides of the car's headlamp HL.
8. Switch (H/SW) that transmits the height of headlamp HL from the ground to the microcomputer 9
and various switches such as the continuous switch (C/SW) 9', the luminous intensity 10 of the optical axis of the reduced light distribution pattern, the horizontal angle 11 of the optical axis or the edge of the high luminous intensity band, the vertical angle 12, etc. A display section for displaying information is provided. 13 is a level provided on the upper surface of the measuring section.

Then, the head lamp is
It is configured to condense the light from HL and obtain a pattern similar to that 10 meters away, and also includes half mirror 3,
The optical axis is bent by using a mirror 4, etc. to make it more compact. Further, the signal from the light amount sensor is processed by an electronic circuit, and the result is displayed as a numerical value or on a lamp, and the light amount sensor is configured to move within the range of the pattern by a drive mechanism described later.

FIG. 6 is a diagram showing details of the light receiver section in FIG. 5,
This figure shows the specific configuration of FIG. 4, which shows an example of a means for moving the aforementioned optical sensor array Sm to collect light amount data.

In FIG. 6, reference numeral 14 denotes an optical sensor array, and this optical sensor array 14 corresponds to the optical sensor array Sm in FIG.
This optical sensor array 14 includes light amount sensors 15(1), 15(2), . . . corresponding to the light amount sensors _s1 to _sn in FIG.
15(m) fixed to a sensor holder,
It is fixed to sliders 17, 17' via a bracket 16. 18, 18' are brackets 19,
A guide rail fixed to the chassis 20 via a guide rail 19' holds the sliders 17, 17' slidably. Here, there are m light quantity sensors 15.

An L-shaped fitting 21 is protruded from the slider 17 and engages with a belt 24 driven by a motor 22 and a pulley 23, and is engaged with a belt 24 driven by a motor 22 and a pulley 23.
8'. Also,
A photo sensor 25 corresponding to the position detection sensor PDS shown in FIG. 4 is fixed to the lower surface of the slider 17'.
Signal plate 26 (fourth signal plate) fixed to chassis 20
(corresponding to the position mark plate PM in the figure).

In addition, in the figure, H indicates a horizontal line, and V indicates a vertical line.

FIG. 7 is a block diagram showing the basic configuration of a processing section that processes data obtained by the data sampling means for the reduced light distribution pattern shown in FIGS. 4 and 6. FIG. In the figure, HL is a headlamp, and L is a condensing lens.
On the HV plane, it is possible to obtain a light distribution that is similar to the 10 meter light distribution. And this optical sensor row
Sm has m light amount sensors s ₁ to s _n arranged at regular intervals on a straight line, and each sensor can capture the light amount at m locations on the straight line.

LA is an optical amplifier that amplifies the output (light amount signal) of the optical sensor array Sm, and is composed of m independent amplifiers LA ₁ to LA _n for each of the light amount sensors s ₁ to _{s n} . SCN is a scanning section, and this scanning section SCN has a function to time-divide m amplified light intensity signals sent out from the optical amplifier LA and send them to the analog-to-digital converter AD, and this time-division operation is performed by the microcomputer MPU. It is configured to be controlled by command α from . The analog-digital converter AD has a function of converting the analog quantity sent from the scanning unit SCN into a digital quantity, and is also configured to be controlled by command β from the microcomputer MPU. has been done.

The PDS is a position detection sensor directly connected to the optical sensor array Sm, and is configured to read the position mark (~position of side AB) on the fixed position mark plate PM by the movement of the optical sensor array Sm. (See Figure 4). The position detection signal σ is then input to the microcomputer MPU.
DRV is a drive unit for moving the optical sensor array Sm as shown in FIG. 4, and is configured to operate in response to command γ from the microcomputer MPU.

SW is a switch group for providing information on the operation of the device, and this switch group SW includes light distribution measurement start switches S, SW, continuous switches C, SW for continuous operation of optical sensor array Sm, and automobile headlights. A microcomputer separates the left and right sides of the HL.
Consists of switches RL and SW to inform the MPU, and switches H and SW to inform the microcomputer MPU of the height of the head lamp HL from the ground.
The information is relevant at the time of the light distribution determination criteria. The microcomputer MPU is a memory circuit MEM for storing programs and light amount data for executing the operation of the optical axis detection device according to the present invention.
It consists of an input/output circuit (I/O) that transmits data and instructions to and from the outside, and a central processing unit (CPU) that controls these.

DP is a display panel that displays the results after light distribution measurement. For example, the luminous intensity of the optical axis of the reduced light distribution pattern, the horizontal angle and vertical angle of the optical axis or the edge of the high luminous intensity band, etc. are displayed using digital numbers or a pointer meter, and these three values are displayed. It is configured to display pass/fail results compared to standard values using lamps.

Next, the operation of the embodiment shown in FIG. 7 will be explained with reference to FIG. 2, FIG. 4, and FIG. 5. First, aiming (optical axis adjustment) of the headlamp HL.
To do this, first align the lamp shaft O- as shown in Figure 2.
So that O' and the axis P-O ₁ of the device are in the same straight line,
Directly face the device and turn on the headlamp HL. After this, measurement is started by pressing the light distribution measurement start switch (start switch) S, SW in Fig. 7, the collected light amount data is stored in the memory circuit MEM in the microcomputer MPU, and processed according to the purpose. After doing so, the results are displayed on the display panel DP.

Next, the means by which the microcomputer MPU stores the light quantity data of the reduced light distribution pattern will be explained.

First, when the start switches S and SW are pressed, the microcomputer MPU activates the optical sensor array Sm.
By transmitting the command γ to the drive unit DRV, the optical sensor array Sm begins to linearly translate in the direction from A to B on the side AB shown in FIG. This movement causes the position detection sensor to
When the PDS captures the position mark on the position mark plate PM (see FIG. 4), the position detection signal σ is input to the microcomputer MPU.

On the other hand, _the amount of light captured by the light amount sensors s _{1 to s n at} the positions on the side AB shown in FIG _.
is converted into an amplified light amount signal.

Therefore, the amount of light captured by the light amount sensors s ₁ to _{s n} is determined by the position detection signal σ detected by the microcomputer.
At the same time as the input to the MPU, the microcomputer MPU gives a command α to the scanning unit SCN to sequentially switch from the first to the mth scan unit, and receives the command β from the microcomputer MPU each time to input the command α into the analog-to-digital converter AD. becomes a digital quantity, and the memory circuit in the microcomputer MPU
They are stored sequentially in MEM.

In this way, m pieces of light intensity data have been acquired at the position on the side AB, and after a while, the position detection sensor PDS captures the position mark on the position mark plate PM due to the movement of the optical sensor array Sm. m of the position on side AB by the above method
Stores light amount data.

This series of operations is repeated n times, and when the optical sensor array Sm reaches the position shown in Fig. 4, the memory circuit
The MEM can store n×m pieces of total light amount data.

Also, if you turn on the continuous switches C and SW and press the start switches S and SW, the optical sensor array Sm
makes a reciprocating motion from the starting point to the ending point and from the ending point to the starting point,
Data on the optical axis, luminous intensity, and judgment signal are displayed moment by moment on the display panel DP for each scan.

Next, based on the light intensity data collected as described above, the microcomputer MPU executes a program to calculate the direction angle of the optical axis and the edge of the high luminosity band, and calculates the reference value pre-stored in the memory circuit MEM. It is compared with the standard values specified by switches H, SW, RL, and SW, and the results are displayed on the display panel DP. Therefore, when the measurer looks at the displayed value on the display panel DP or the judgment lamp, the head lamp HL
You can see the measurement results at a glance, including pass/fail depending on the mounting position.

Next, an example of a method of processing light amount data will be explained. Here, how to determine the optical axis of the traveling beam and how to calculate the optical axis direction angle will be explained using FIG. 8. In the figure, W indicates the reduced light distribution pattern of the headlamp HL on the HV plane of the horizontal line H and the vertical line V, the rectangle ABCD indicates the range of light amount data stored in the microcomputer MPU, and the straight line O- O ₁ −O′ indicates the lamp axis. First, a reduced light distribution pattern W is projected on the HV plane, and the light amount data within the rectangle ABCD has already been stored. From this light amount data, a point M having the highest luminous intensity is found, and an isoluminous curve N having a value of n% of this maximum luminous intensity is drawn. This isoluminance curve N becomes a certain luminous band whose optical axis can be determined, and its geometric center O ₂ is determined, and O
−O ₂ is defined as the optical axis. The optical axis O- _O2 determined in this way matches human visual perception. next,
How the optical axis O- _O2 is inclined with respect to the lamp axis O- _O1 is expressed by an angle with respect to the lamp axis O- _O1 .

That is, the distance between the sensors on the virtual screen _SC1 on which the reduced light distribution pattern is projected is replaced by an angle using the calculation equation using the relational expression between the reduction rate and the distance determined as shown in FIG. Therefore, in FIG. 3, since the light sensor array Sm has the light quantity sensors s ₁ to s _n arranged on a straight line at a certain interval, the light quantity sensors s _{1 to} s n at the ~ position of the optical sensor array Sm Each point ~s _n is determined by an angle with respect to the lamp axis O-O ₁ -O'. Therefore,
All m x n measurement points are on the lamp axis O-
It is given by the angle with O ₁ −O′. And m×n
Since the individual measurement light amount data is stored in the memory circuit MEM, the aforementioned geometrical center _O2 is calculated by the microcomputer MPU and expressed as an angle, and the optical axis O- _O2 is aligned with the lamp axis O- It is possible to detect which direction it is tilted with respect to O ₁ .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, transparent portions and non-transparent portions are arranged alternately, and the widths of the transparent portions and non-transparent portions are larger than the width of the transparent portions and non-transparent portions. A position mark plate is provided with a wide section, and one and the other of the wide sections are added as a light-transmitting section and a non-light-transmitting section. A position detection sensor that moves simultaneously with the sensor array and detects the width of the light-transmitting portion and non-light-transmitting portion of the position mark plate as its output signal width as it moves; The amount of light is collected by the optical sensor array at each boundary between the transparent part and the non-transparent part of the position mark plate, which is detected as an edge change from one side to the other, and the starting point and the starting point for moving the optical sensor array are collected. Since the end point is determined in the wide section detected based on the output signal width of the position detection sensor, it is possible to collect the light intensity data of the similarly reduced light distribution pattern in an orderly manner. By instantaneously collecting the light quantities of the light quantity sensors s ₁ to s _n , it is possible to collect m×n pieces of data, so the practical effect is extremely large. Further, according to the present invention, JIS,
The irradiation direction can be determined without depending on the SAE or European light distribution pattern, or whether it is a driving beam or a passing beam, and it is also possible to measure light distribution at a short distance of 10 meters from the headlight. Since measurements can be made, there are no problems due to distance from the headlight, and excellent effects such as not requiring a large space for measurement equipment can be achieved. Since the method uses a method to process data in an appropriate manner, it is extremely effective in that it is possible to make judgments that suit visual perception.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an example of a conventional headlight tester for inspecting the irradiation direction of automobile headlamps, and Fig. 2 is a diagram showing a means for reducing a 10-meter pattern to a short distance, which is used to explain the present invention. FIG. 3 is an explanatory diagram of the axis of the headlamp and the rotation angle of the headlamp in a plane perpendicular to the center line of the headlamp used to explain the present invention. FIG. 4 shows an example of the data sampling means for the light distribution pattern. FIG. 5 is a perspective view showing the structure of an embodiment of the optical axis detection device for an automobile headlamp according to the present invention, and FIG. 6 is an explanation showing the structure of the light receiver section in the embodiment of FIG. 5. 7 are block diagrams showing the basic configuration of the processing section of the present invention, and FIG. 8 illustrates an example of how to determine the optical axis of a traveling beam and how to calculate the angle of the optical axis direction in order to explain the present invention. FIG. HL...Headlamp (headlight), L...Condenser lens, SC ₁ ...Virtual screen, Sm...Light sensor array, s ₁ to s _n ...Light level sensor, PM...Position mark plate, PDS... ...Position detection sensor.

Claims (1)

[Claims] 1 The light distribution pattern of automobile headlamps is similarly reduced using a condensing lens to create a reduced light distribution pattern, and a light sensor array in which multiple light intensity sensors are arranged at regular intervals on a straight line is In a device that collects the light intensity of a large number of points over the entire surface of the reduced light distribution pattern by translational movement, and detects the optical axis of an automobile headlamp based on the collected light intensity data, The translucent portions and non-transparent portions are arranged alternately, and a wide section is provided at both ends thereof, the width being wider than the translucent portion and the non-transparent portion. A position mark plate which is added as a part and a non-light transmitting part is arranged so that its center coincides with the center axis of the optical sensor array, and moves simultaneously with the optical sensor array, and as the position mark plate is moved, the position mark plate is added as a non-transparent part. A position detection sensor that detects the width of the light-transmitting part and the non-light-transmitting part of the plate as the width of its output signal, and the position detected as an edge change from one side to the other side of the output signal of this position detection sensor. The amount of light is collected by the optical sensor array at each boundary between the transparent portion and the non-transparent portion of the mark plate, and the output signal width of the position detection sensor is used to determine the starting point and end point for moving the optical sensor array. an optical axis detection device for an automobile headlamp, comprising control means for performing detection in the wide section based on the above.