JPH034858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a two-dimensional light distribution measuring device for a light source, which can measure the light distribution of a light source, etc. in real time.

(Prior Art) Since the light distribution characteristics of a light source are important criteria for selecting the light source, manufacturers of light sources often describe the orientation characteristics of the light source in specifications and the like.

However, measuring this light distribution characteristic required considerable work.

An example of conventional light distribution measurement will be briefly described with reference to FIG.

Conventional light distribution measurement, as shown in Figure 4,
A photodetector 2 such as a photomultiplier tube or a photodiode is placed at a position sufficiently distant from the light source 1 to be measured.

Then, by moving the photodetector 2 itself on a concentric circle with respect to the light source 1 to be measured, measurements are taken at each position, and the light distribution of the light source is measured one-dimensionally and discretely.

Note that by rotating the light source 1 by 90 degrees around its optical axis and performing similar measurements, the three-dimensional light distribution can be estimated.

(Problems to be Solved by the Invention) In order to obtain highly accurate measurement data using the measurement method described above, it is necessary to measure the number of times to meet the accuracy.

Furthermore, since the photodetector needs to be sufficiently far away from the light source to be measured, a large space is required.

Furthermore, there is a problem in that a measurement chamber must be provided to block light other than the light source to be measured. Moreover, when considering reproducibility,
It has the disadvantage of being prone to errors. Furthermore, the basics of the measurement method mentioned above are only one-dimensional, and two-dimensional.
In order to obtain dimensional data, it is necessary to perform the one-dimensional measurement multiple times.

In any case, the method described above requires a very large amount of time when measuring the light distribution because the measurement is performed at each location.

More importantly, since each point cannot be measured simultaneously, if the luminous flux emitted from the light source to be measured is unstable, measurement becomes virtually impossible.

The invention of a radiation angle distribution measuring device disclosed in Japanese Patent Application Laid-Open No. 59-120932 proposes simultaneous measurement of radiation angle distribution.

In the present invention, the light source to be measured is placed on the front focal plane of the objective lens, and the light beam after passing through the objective lens is made into a parallel light beam and is incident on the image detection element.

This device solves the problems caused by time lag. However, this device is applicable only to a light source to be measured that has an extremely small light emitting area, such as a laser diode that is not a surface emitting type.

In the case of a light source with a large light emitting area, the light beam after passing through the objective lens will contain various angular components.

In addition, in this optical system, if the positional relationship between the objective lens and the light source to be measured changes, the optical path after passing through the objective lens changes, and the illuminance distribution on the image detection element changes, so the light source to be measured changes. A movable or optical path switchable condensing lens is used as an auxiliary means for adjusting the position to always be constant in the axial direction and in a plane perpendicular to the optical axis. In any case, if the positional relationship between the objective lens and the light source to be measured is not maintained correctly, or if the light source is difficult to maintain, good measurement results cannot be obtained.

A first object of the present invention is to provide a light source that can measure the light distribution of a light source in real time, which can solve all the problems of the conventional method.
An object of the present invention is to provide a dimensional light distribution measuring device.

A second object of the present invention is to further perform image processing on the measurement data to obtain data that can be used to more quantitatively evaluate the characteristics of a light source.
An object of the present invention is to provide a dimensional light distribution measuring device.

(Means for Solving the Problems) In order to achieve the first object, the two-dimensional light distribution measuring device for a light source according to the present invention includes a collimator lens system in which the light source to be measured is arranged near the front focal position. a relay lens system that re-images the intensity distribution image of the light source to be measured generated on the rear focal plane of the collimator lens system; a television imaging device that captures the re-imaged image; It consists of an output device that outputs the output of the television imaging device.

In order to achieve the second object, the two-dimensional light distribution measuring device for a light source according to the present invention includes a collimator lens system in which the light source to be measured is arranged near the front focal position, and a rear focal point of the collimator lens system. a relay lens system that re-images the intensity distribution image of the light source to be measured generated on the surface; a television imaging device that captures the re-imaged image; and a television imaging device that captures the output of the television imaging device into another image. The image processing apparatus is comprised of an image processing device that converts the image into an image, and an output device that outputs the output of the image processing device.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 is a layout diagram showing an embodiment of the first two-dimensional light distribution measuring device according to the present invention.

Of the light emitted from the light emitting point placed near the front focal point of the collimator lens system 3, a beam parallel to the optical axis is focused by the collimator lens system 3 on the rear focal point position on the optical axis.

In addition, the collimated light flux emitted from the light emitting point at a certain angle is moved by the collimator lens system 3 to a position on the back focal plane corresponding to the angle emitted from the light source 4 to be measured, in proportion to the intensity in the emitted direction. An aerial image 5 showing a two-dimensional intensity distribution is formed.

In the present invention, the light source 4 to be measured is arranged near the front focal point of the collimator lens system 3 in order to form the distribution of the light on the rear focal plane of the collimator lens system 3.

When the light source 4 to be measured is a semiconductor laser or the output end of an optical fiber, the aerial image 5 showing the two-dimensional intensity distribution generated on the rear focal plane of the collimator lens system 3 is based on the structure of each light source. It shows an intensity distribution corresponding to the transverse mode of the light emission pattern originating from , and is generally called a far-field pattern.

A relay lens system 8 is provided to refocus the aerial image 5 showing this two-dimensional intensity distribution onto the effective size of the imaging surface 7 of the television imaging device 6.

When the video signal obtained from the television imaging device 6 is guided to the television monitor 9, a two-dimensional light distribution image of the light source 2 to be measured proportional to the aerial image 5 showing the two-dimensional intensity distribution is displayed on the television monitor 9. can be observed.

In the embodiment described above, it is preferable that the collimator lens system 3 has the following relationship between the incident angle θ of the light beam and its image height h.

h=f·θ...(1) For that purpose, it is preferable to use an f·θ lens.

However, the actual collimator lens system 3 does not necessarily satisfy the above condition (1).

According to the second configuration of the present invention, the problems such as the distortion can be solved even if the normal collimator lens system 3 is used.

FIG. 2 is a layout diagram showing an embodiment of the second configuration. light source 4, collimator lens system 3, aerial image 5,
The arrangement and function of the relay lens system 8 and the television imaging device 6 are the same as in the embodiment previously described with reference to FIG.

As mentioned above, the collimator lens system 3 has the above-mentioned (1)
The relay lens system 8 does not satisfy the formula and can also have distortion.

However, these are known individually and can be collectively quantified as distortion of the optical system.

Furthermore, when considering the entire system, scanning distortion of the imaging system may also be considered, but this is also known.

Therefore, this amount is stored in advance in the storage device 10 in correspondence with the image.

The image processing device 11 can refer to the contents of the storage device 10, process the video signal, and obtain data from which all positional distortions of the entire system have been removed.

By digitally converting the data from which all distortions of the entire system have been removed and inputting it into the output digital storage device, two-dimensional light distribution measurement data of the light source can be obtained by reading out this data.

Further, the information can be displayed on the television monitor 9 similarly to the embodiment described above.

In this example device, the data subjected to the distortion correction is further subjected to image processing to convert it into an isoluminance line curve as shown on the monitor 9 in FIG. It can be converted into three-dimensional perspective view representation data as shown in FIG.

Various modifications can be made to the embodiments described in detail above within the scope of the present invention.

The image processing described above can be performed selectively, and it is also possible to perform equal brightness display or stereoscopic display without correcting distortion.

Furthermore, the optical axis of the light source to be measured does not necessarily have to coincide with the optical axis of the optical system.

By recording the inclination, it is possible to obtain data that cannot be obtained if the inclination is aligned with the optical axis of the optical system.

(Effects of the Invention) As described above in detail, the two-dimensional light distribution measuring device for a light source according to the present invention includes a collimator lens system in which the light source to be measured is arranged near the front focal position;
a relay lens system that re-images the intensity distribution image of the light source to be measured generated on the rear focal plane of the collimator lens system; a television imaging device that captures the re-imaged image; It consists of an output device that outputs the output of the imaging device.

Therefore, the two-dimensional light distribution of the light source can be measured in real time.

Since it can be measured in real time, it is also possible to easily measure the two-dimensional light distribution of light sources with fluctuations in intensity, which could not be measured using conventional methods.

What kind of fluctuations there are can also be observed on the monitor.

More importantly, in the optical system of the present invention, if aberrations other than distortion of the collimator lens system are completely corrected, the light source to be measured can be moved from the front focal point of the collimator lens system in the optical axis direction or Even if the light beam is shifted in the direction perpendicular to
It is to focus on one point at the position of f·tanθ. Therefore, geometrically, even if the light source to be measured is placed at a position away from the front focus of the collimator lens system, there will be no effect on the measurement results.

Furthermore, since the optical system can be made small, the influence of external light can be avoided by covering the light source to be measured and the optical system with a simple hood.

Therefore, there is no need to consider the use of a darkroom as in the conventional method.

Note that if the light source 4 to be measured is placed accurately at the front focal position of the collimator lens system 3, the collimator lens system 3 will function as a Fourier transform optical system, and the aerial image 5 generated at the rear focal position will be located at the front focal position of the collimator lens system 3. Since it is a Fourier diffraction image of the light source 4, the emission distribution characteristics of the optical axis can be analyzed.

Next, the second configuration of the present invention includes, in addition to the above configuration,
The image processing apparatus includes an image processing apparatus that converts the output of the television imaging apparatus into another image.

Therefore, by processing the output of the television imaging device, it becomes possible to display equal brightness or stereoscopic display, which is easier to understand intuitively.

Next, since the distortion of the entire system is known, image processing can be performed with reference to that data.

As a result, there is no need to use expensive f/theta lenses.

[Brief explanation of drawings]

FIG. 1 is a layout diagram for explaining an embodiment of a first configuration of a two-dimensional light distribution measuring device according to the present invention. FIG. 2 is a layout diagram for explaining an embodiment of the second configuration of the two-dimensional light distribution measuring device according to the present invention. FIG. 3 is a graph showing a display example of an output image processed by the embodiment apparatus having the second configuration. FIG. 4 is a layout diagram showing a conventional light distribution measuring method. 3... Collimator lens system, 4... Light source to be measured, 5
... Aerial image, 6... Television imaging device, 8... Relay lens system, 9... Television monitor, 10... Storage device, 11... Image processing device, 12... Output data storage device.

Claims (1)

[Scope of Claims] 1. A collimator lens system in which the light source to be measured is arranged near the front focal position, and re-imaging the intensity distribution image of the light source to be measured generated on the back focal plane of the collimator lens system. a relay lens system, a television imaging device that captures the re-imaged image;
A two-dimensional light distribution measuring device for a light source, comprising an output device that outputs the output of the television imaging device. 2. The two-dimensional light distribution measuring device of a light source according to claim 1, wherein the output device is a television monitor. 3. The two-dimensional light distribution measuring device for a light source according to claim 1, wherein the light source to be measured is a laser diode, a light emitting end of an optical fiber, or the like. 4 a collimator lens system in which the light source to be measured is arranged near the front focal position; a relay lens system that re-images the intensity distribution image of the light source to be measured generated on the rear focal plane of the collimator lens system; a television imaging device that captures the re-imaged image;
A two-dimensional light distribution measuring device for a light source, comprising an image processing device that converts the output of the television imaging device into another image, and an output device that outputs the output of the image processing device. 5. The two-dimensional light distribution measuring device of a light source according to claim 4, wherein the image processing device is a device that includes processing for correcting distortion of an optical system. 6. The two-dimensional light distribution measuring device of a light source according to claim 4, wherein the image processing device is an image processing device that converts the output of the television imaging device into isobright line image data. 7. The two-dimensional light distribution measuring device for a light source according to claim 4, wherein the image processing device is an image processing device that converts the output of the television imaging device into a perspective stereoscopic view.