JPS60104235A - Optical axis measuring device - Google Patents

Abstract

PURPOSE:To detect a shift angle by photographing by a TV camera plural images obtained by extracting the light radiated from an optical system to be measured, through a half prism, etc. placed so as to be separated by a prescribed distance, and superposing and displaying its video signal on a display. CONSTITUTION:A half prism 13 and a total reflection prism 14 are placed on an optical axis of an optical system to be measured 10. Each light reflected by both the prisms is synchronized with a signal from a synchronizing signal generator 15 and picked up its image by A and B TV cameras. Each photographed video signal, etc. is inputted to an operating part 16, also sent to a display 16, and superposed and displayed. By using a circle A and B, various measurements of the optical system to be measured are executed easily. Time data in both ends of each circle in case of scanning in a shaped crossing the center of the circles A and B displayed on the display 17 is extracted, and shift angles theta, theta' of light radiated from the optical system to be measured are calculated by putting said data in a prescribed expression, and derived and displayed on an indicator 18. In this way, axial observation and axial measurement of various optical systems can be executed without injuring eyes by a laser light source.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to an optical axis measuring device, particularly an optical axis measuring device for measuring the axis of an optical system such as a CD (compact disc) device using a plurality of television cameras. It is related to the device.

(Technical background and problems) Optical system 1 For example, an optical system that includes a light source and a lens system must be adjusted in various ways, such as optical axis adjustment and distance adjustment, between the light source and lens system during assembly to maximize its performance. There is a need to do.

However, semiconductor lasers that emit strong coherent light are used as light sources for optical systems such as CDs, and in order to align the optical axes of CD optical systems, laser beams cannot be detected by human eyes as in the past. Direct observation would risk damaging one person's eyes. In order to avoid this risk, it is difficult to align the optical axis because the direction of the light emitted from the optical system cannot be determined by simply photographing the light emitted from the optical system such as a CD with a television camera. death.

Another problem is that it is difficult to align the convergence or parallel irradiation of the light emitted from the optical system to a predetermined state.

(Object and Structure of the Invention) An object of the present invention is to solve the above-mentioned problems, and to emit light emitted from the optical system to be measured 1, for example, an optical system of a CD, through a half prism or the like arranged at a predetermined distance. Photographed by multiple television cameras.

The objective is to measure the axis of the optical system to be measured by displaying video signals from each television camera on a display.

Therefore, the optical axis measuring device of the present invention includes at least one extractor that extracts a part of the light emitted from the optical system to be measured, and a television that converts the image of the light extracted by the extractor into an electrical signal. a camera, a display that superimposes video signals from the television camera extracted at at least two positions on the optical axis and displays the image in the form of a single image, and a position of each image based on the video signal from the television camera. a position detection section that detects the deviation angle of the light emitted from the optical system to be measured based on the signal from the position detection section; It is characterized by comprising a display device that displays the corner.

(Example of the invention) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an embodiment of the present invention, FIG. 2 is an explanatory diagram explaining one embodiment of the present invention shown in FIG. 1, FIG. 3 is another embodiment of the present invention, and FIG. FIG. 5 is an explanatory diagram illustrating another embodiment of the present invention. FIG. 5 shows a configuration diagram of one embodiment of the present invention.

In the figure, 10 is an optical system to be measured, 11 is a light source, 12 is a lens, 13 is a half prism, 14 is a total reflection prism, 15
1 is a synchronizing signal generator, and 16 is an arithmetic unit.

Reference numeral 17 indicates a display 518, and 19 indicates a key manual section.

In FIG. 1, reference numeral 11 in FIG. 3 is a light source that constitutes the optical system to be measured 10, and is, for example, a semiconductor laser or the like that emits strong coherent light used in CDs or the like. In order to accurately focus the light emitted from the light source 11 into a predetermined position 1, for example, a focus position recorded concentrically on the CD surface of a CD device, in the form of a minute spot, the light source 11 is It is necessary to accurately align the axes of the lens 12 and the lens 12.

One example of alignment is optical axis alignment, in which the optical axis of the light source 11 and the optical axis of Lenz ζ 12 are aligned. In order to perform the optical axis alignment, it is necessary to measure the deviation angle θ between the optical axis of the light source 11 and the optical axis of the lens 12. Therefore, as shown in FIG. 1, there is a distance in front of the optical system consisting of the light source 11 and the lens 12.
The half prism 13 and the total reflection prism 14 are arranged so as to coincide with the optical axis of the lens 12 with an interval of 131tL, and the light reflected by the nof prism 13 is captured by a television camera A. Photographed, total reflection prism 1
The light reflected by 4 is photographed by the B television camera.

The images taken by the A television camera and the B television camera are shown in circles A on the illustrated display f in FIG. 2 (C).
and is represented in the shape of circle B. The video signals from the A television camera and the B television camera when scanning on the straight line indicated by the arrow (■) passing through the center of the nucleus are shown in FIGS. 2(a) and 2(b), respectively. - The time difference between the center of the circle and the center of circle B (is determined by the following formula.

t = (T2 +74)/2. - (T L+'r3
)/, 2 where Tl to T4 represent the time at each point of circles A and B shown in FIG. 2, respectively. The time difference t is the first
As shown in the figure, this corresponds to the angle (deviation angle) θ at which the light source 11 is displaced from the optical axis, and from the scanning speed of the A television camera or the B television camera, etc., the half prism 13 and the total reflection prism 14 are is expressed as a distance difference l from the optical axis at each reflection position. Therefore, the deviation angle θ of the light source 11 with respect to the lens 12 as shown in FIG. 1 is measured as a value shown in the following formula.

θ-Arctan (n/L) Here, L is the distance between the half prism 13 and the total reflection prism 14.

Generally, when assembling an optical system, it is necessary to adjust the optical axes of the light source 11 and the lens 12 so that the deviation angle θ becomes zero. Alternatively, the light source 11 may be fixed and the lens 12 may be moved to adjust the deviation angle θ to zero.
Alternatively, the adjustment may be made by moving both.

Figure 3 shows the alignment of the optical system between light source 11 and lens 1.
One example of measuring displacement from an optimal distance between two is shown.

Both the light source 11 and the lens 12 have the same optical axis.
If the distance between them is aligned.

In this embodiment, a parallel light beam having a disk-shaped cross section is emitted from the lens 12. On the other hand, if the distance between the two is not aligned, the diameter of the cross section of the emitted light will be sequentially expanded or decreased as the lenses 12 move away from each other. For example, as shown in FIG. 3, when the diameter of the cross section of the emitted light increases with a shift angle θ.

The images taken by TV camera A and TV camera B are shown as circles A and B, respectively, on the illustrated display in Figure 4 (C).
It can be expressed as concentric circles. The video signals from television camera A and television camera B when scanning on the straight line indicated by the arrow (■) passing through the center of the nucleus are shown in FIGS. 4(a) and 4(b), respectively.

The time difference t' corresponding to the difference between the diameter of circle B and the diameter of circle A is determined by the following formula.

t" = (T4-TI)'-(T3-T2) where T
I to T4 represent time differences at each point of circles A and B shown in FIG. 4, respectively.

The time difference t' corresponds to the displacement of the position of the light source 11 from the focal position of the lens 12, as shown in FIG. It can be expressed as a distance l' corresponding to the difference in diameter of the emitted light that reaches the reflection position of the half prism 13 and the total reflection prism 14 from the scanning speed of the A television camera or the B television camera, etc. Therefore, the deviation angle θ' of the emitted light emitted from the lens 12 shown in FIG. 3 is not shown in the formula below, but is measured as a value.

θ' = Arctan (ρ'/2L) where L is the distance between the half prism 13 and the total reflection prism 14. Furthermore, if the focal length of the lens 12 is determined, the lens 12
The displacement at the focal point position can be measured.

The distance between the light source 11 and the lens 12 is adjusted by adjusting the distance between the light source 11 and the lens 12 when assembling the optical system so that the deviation angle θ' becomes zero.

In addition, Fig. 2 (a), (b) or Fig. 4 (a).

(b) The times TO to T4 shown are determined by detecting the changing position by differentiating the signal scanned or extracted from the position indicated by the arrow ■ in Fig. 2 (c) or Fig. 4 (c), and It can be measured by counting the synchronization signal or reference clock signal.

In FIG. 5, 10 in FIG. 2 is the optical system to be measured,
It is composed of a light source 11 such as the semiconductor laser described above and a lens 12. A half prism 13 and a total reflection prism 14 are arranged on the optical axis of the optical system 10 to be measured, and the light reflected by both prisms is synchronized with a signal from a synchronization signal generator 15 and sent to a television camera A and The video signals and the like taken by the B television camera are respectively input to the calculation unit 16 and sent to the display 17, where they are displayed in a superimposed manner as shown in the figure.

Various measurements of the optical system to be measured can be easily performed using the illustration A and the circle B superimposed on the display 17.

Furthermore, as explained using FIG. 2 and FIG.
Extract the time data (To to T4) at both ends of each day when scanning across the center of Calculate it. Then, the values of the deviation angles θ, θ′, etc. are displayed on the display 18.

In addition, instructions for various corrections of the optical system to be measured 10, deviation angles θ, θ
Instructions for displaying "" are given by the key human power section 19.

(Effects of the Invention) As explained above, according to the present invention, a plurality of images extracted from the light emitted from the optical system to be measured through a half prism etc. arranged a predetermined distance apart are photographed by a television camera. , to superimpose and display the video signal from the television camera on the display 17, detect the deviation angle, perform predetermined calculations, and execute axis measurement of the optical system to be measured;
This allows you to intuitively observe the degree of axis measurement.

It can be measured in the form of quantitative numbers. Also.

Even if the optical system to be measured uses a semiconductor laser as a light source, there is no danger of damaging the human eye, and axis observation and axis measurement of various optical systems can be performed.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the present invention, FIG. 2 is an explanatory diagram explaining one embodiment of the present invention shown in FIG. 1, FIG. 3 is another embodiment of the present invention, and FIG. FIG. 5 is an explanatory diagram illustrating another embodiment of the present invention. FIG. 5 shows a configuration diagram of one embodiment of the present invention. In the figure, 10 is an optical system to be measured, 11 is a light source, 12 is a lens, 13 is a half prism, 14 is a total reflection prism, 15
1 is a synchronizing signal generator, and 16 is an arithmetic unit. Reference numeral 17 represents a display, 18 a display, and 19 a key manual section. Patent Applicant: Alps Electric Co., Ltd. Representative Patent Attorney Hiroshi Mori 1) (3 others)

Claims (1)

[Claims] at least one extractor for extracting a portion of the light emitted from the optical system to be measured; a television camera for converting an image of the light extracted by the extractor into an electrical signal; and at least two positions on the optical axis. a display that superimposes video signals from the television camera extracted in and displays the image in the form of an image; a position detection section that detects the position of each image based on the video signal from the television camera; A deviation angle calculation section that calculates the deviation angle of light emitted from the optical system to be measured based on a signal from the optical system to be measured, and a display that displays the deviation angle based on the signal from the deviation angle calculation section. Optical axis measuring device 6