JP2808221B2 - Light distribution characteristic measuring device for vehicle lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the light distribution characteristics of a vehicle lamp using an illuminometer.

[0002]

2. Description of the Related Art For example, a headlamp for a vehicle is required to have a performance of illuminating a relatively distant place, and at the same time, a performance of not giving glare to a driver of an oncoming vehicle. It is stipulated in JIS from the point of view.

In order to measure such characteristics, conventionally, for example, a screen provided with a hole near the center is prepared, a light receiver is arranged on one side of the screen, and a lamp for measurement is arranged on the opposite side. ing. Then, the lamp is mechanically moved in the horizontal direction by a minute distance and temporarily stopped, and then the output of the light receiver is measured. The movement of the minute distance is repeated to move the lamp to a predetermined position in the horizontal direction.

After that, the lamp is slightly moved in the vertical direction, and the light distribution characteristics in the horizontal direction are measured again. The light distribution characteristics can be measured by repeating the operation.

[0005]

The light distribution characteristics of a required area can be measured by performing such a measurement. However, since the measurement is stopped after moving a small distance, the waiting time until the light distribution becomes stable is measured. For example, it takes several hours to measure the light distribution characteristics of one lamp, depending on the required measurement accuracy. For this reason, there is a problem that even if it is desired to measure a delicate part again or to measure and compare the light distribution characteristics of different types of lamps, it is not easy to perform because the measurement time is too long. .

[0006] The present invention has been made in view of such a situation, and is intended to reduce the measurement time by continuously moving a lamp.

[0007]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention rotates continuously in the horizontal direction within the light distribution characteristic measuring range, and when the rotation reaches an end in the horizontal direction. A turntable that moves slightly in the vertical direction, a position detection device that generates a position signal of the turntable, a memory that stores the illuminance measurement result corresponding to the horizontal position, and light distribution from the horizontal position signal and the illuminance measurement result And a data processing device for obtaining characteristics.

[0008]

The turntable is continuously rotated in the horizontal direction, and the illuminance measurement result is stored together with the position signal. When the measurement in the horizontal direction is completed, the turntable is slightly moved in the vertical direction and then continuously rotated in the horizontal direction again. If this is repeated, the light distribution measurement range will be swept, so after the measurement of the predetermined range is completed, data processing of the data in the light distribution characteristic measurement range is performed based on both stored data, and the light distribution characteristic is changed. can get.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, a lamp 1 to be measured is mounted on a turntable 2, and the turntable 2 is driven by a motor control device 3. That is, the rotary table 2 is configured to be continuously rotatable in the horizontal direction within the light distribution characteristic measurement range by the motor control device 3, and to be finely movable in the vertical direction at the end in the horizontal direction.

The motor control device 3 is provided with a position detecting device 4 for generating a position signal for detecting the position of the turntable 2 when the turntable 2 is rotated in the horizontal and vertical directions. The resulting signal is supplied to the address signal generator 5 and converted into an address signal.

In this example, the position signal detecting device 4 is
It is composed of a pulse encoder that generates a pulse when rotates, and a counter that counts the pulse. However, an error occurs if the previous count value remains in the counter at the start of measurement. For example, if "7" remains in the counter as the previous data and a trigger signal is generated at 10 counts, a trigger is generated when three pulses are generated at the start of the next measurement, and the measurement position is determined. Will deviate from the original.

In order to prevent such a situation, in this embodiment, if the pulse of the encoder stops for 50 ms or more,
That is, the counter is automatically cleared when 50 ms or more elapses after the turntable 2 stops.

On the other hand, since the light of the lamp illuminates the screen 6, the light passing through the hole 6 a provided substantially at the center of the screen 6 is received by the light receiver 7 and converted into an electric signal, and is amplified by the low noise amplifier 8. Then, the voltage value is measured by the ultrahigh-speed voltmeter 9. The response speed of the low-noise amplifier 8 and the ultra-high-speed voltmeter is configured to have a performance that can sufficiently follow the level change of the signal output from the light receiver 7. In this case, there may be a case where only a device whose response speed cannot follow the signal level change can be obtained. In this case, although a detailed description of the procedure is omitted, a true light distribution pattern is restored by performing a Fourier transform and an inverse Fourier transform using a measured signal, an impulse response of a measurement system, and a transfer function of the system. Can be.

The signal output from the ultra-high-speed voltmeter 9 is supplied to the memory 10 together with the address signal generated from the address signal generator 5 and measured by the ultra-high-speed voltmeter 9 at the address specified by the address signal of the memory 10. The set value is stored.

Therefore, the rotary table 2 is controlled by the motor control device 3.
Is driven in the horizontal and vertical directions, so that the illumination area on the screen 6 projected by the lamp 1 is swept in the horizontal and vertical directions, and accordingly, the holes 6a of the screen 6 change the light distribution range of the projected image. The result is similar to moving. Then, the light passing through the hole 6a is detected by the light receiver 7, and the result is stored in the memory 10 corresponding to the detected position.

The data supplied to the memory 10 is stored therein, read out by the data processing device 11, output to the output device 12 as a light distribution characteristic curve, and displayed on the display device 13. The light distribution characteristics of the output device 12 are stored in a floppy disk or a hard disk inside the output device 12, and are printed on a recording paper.

Therefore, the measurer can measure while checking the light distribution characteristic printed on the recording paper or the light distribution characteristic displayed on the display device 13, and the measurement result is irrational for some reason. Even in this case, it is possible to immediately notice and perform re-measurement.

Further, since the measurement itself is performed without stopping the turntable 2, there is no need to wait for the shaking of the turntable 2 due to inertia to stop. In the past, a measurement time of several hours was required. The measurement can be sufficiently performed in about several minutes, and re-measurement can be easily performed. FIG. 2 shows a measurement example of the light distribution characteristics printed on the recording paper, and FIG.
3 shows the light distribution characteristics displayed.

FIG. 3 shows the illuminance distribution by lines connecting the portions of equal illuminance, but by setting the internal structure of the display device 13 as appropriate, the range of the range sandwiched by the adjacent equal illuminance lines is the same. As the luminance, the boundary of the portion where the illuminance changes can be clearly displayed. FIG. 4 is an example,
Areas sandwiched between adjacent equal illuminance lines are indicated by hatching. With this display method, adjacent hatched areas can be clearly distinguished.

When reading data from the memory 10, an address signal is supplied to the memory 10 for reading. In this case, data writing and reading cannot be performed at the same timing, but data writing may be performed intermittently, and thus data reading may be performed at a timing when data writing is not performed. .

In this case, the data reading does not necessarily need to be performed with the same precision as the data writing. If very fine precision is not required, the data may be read with a coarser precision than at the time of writing. That is, instead of using all of the address signals used at the time of writing, the address signal may be read out by skipping the address every other or every other address.

In this device, since the lamp 1 sweeps the projected image illuminating the screen 6 horizontally and vertically, not only the necessary light distribution characteristic measurement range but also the illuminance data around it is measured. I have. However, the portion outside the light distribution characteristic measurement range has low illuminance, and that portion is originally unnecessary, so the measurement result is compared with the threshold value, and if it is less than the predetermined value, it is not displayed or printed. ing. However, if it is desired to know the surrounding characteristics for some reason, it is possible to obtain the characteristics expanded to a desired range by appropriately changing the threshold level.

[0023]

As described above, according to the present invention, since the turntable is continuously moved, the measurement can be performed in an order of magnitude shorter than that of the conventional one, so that detailed data can be measured. Alternatively, the light distribution characteristics of the lamp can be measured with various degrees of freedom, for example, the characteristics of the lamp can be compared with various lamps.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a printing result of light distribution characteristics.

FIG. 3 is a diagram illustrating light distribution characteristics displayed on a display device.

FIG. 4 is a diagram illustrating another example of the light distribution characteristics displayed on the display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lamp 2 turntable 3 motor controller 4 position detector 5 address signal generator 6 screen 7 light receiver 8 low noise amplifier 9 ultrafast voltmeter 10 memory 11 data processor 12 output device 13 display device

Claims (2)

(57) [Claims] 1. A light distribution characteristic measuring device for a vehicle lamp, which illuminates an illuminometer with a lamp and measures the light distribution characteristics of the lamp while moving the lamp within the light distribution characteristic measurement range. A rotating table that continuously rotates in one direction and repeats an operation of fine-moving control in a direction perpendicular to the rotating direction when reaching an end in the rotating direction, and a position of the rotating table. A position detection device that generates a position signal; a memory that stores an illuminance measurement result corresponding to the position of the turntable; and a data processing device that obtains light distribution characteristics from the position signal and the illuminance measurement result. A light distribution characteristic measuring device for a vehicle lamp, comprising: 2. A light distribution characteristic measuring device for a vehicle lamp, which illuminates an illuminometer with a lamp and measures the light distribution characteristics of the lamp while moving the lamp within the light distribution characteristic measurement range. A rotary table that is continuously rotated in one direction, and at the end of the rotary direction, is finely controlled in a direction perpendicular to the rotary direction, and a position that generates a position signal indicating the position of the rotary table. A detection device, a memory for storing an illuminance measurement result corresponding to the position of the turntable, a data processing device for obtaining a light distribution characteristic from the position signal and the illuminance measurement result, and displaying the obtained light distribution characteristic. A light distribution characteristic measuring device for a vehicle lamp, comprising: