JPS6239692B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light beam detection device, and more particularly, to a light beam detection device using an image sensor.

When performing optical measurements using conventional image sensors, the larger the ratio of measurement range to resolution, the more it was necessary to install a large number of image sensors in parallel. For example, as shown in FIG. 1, when the width A of the light beam, especially its lower end position, changes due to the displacement body M, three image sensors S1, S2, S3
are installed in parallel, and the drive pulse DP given to S1 is applied to S2,
S3 was shifted in series, and the outputs of the three image sensors S1, S2, and S3 were taken out as a serial pulse signal through an OR gate. The output waveform at that time is illustrated in FIG.

However, such a device in which image sensors are arranged side by side has the disadvantage that it is technically difficult to line up the plurality of image sensors with high accuracy, and the device is expensive.

An object of the present invention is to provide an inexpensive and highly accurate light beam detection device that utilizes one image sensor for multiple image sensors.

The device of the present invention irradiates a single image sensor with a plurality of superimposed lights using means for bending the optical path such as a mirror prism, and also includes a device for determining the pulse height of the output pulse of the image sensor. It is characterized by determining the number of times the images are superimposed, and having a function substantially equivalent to that of multiple image sensors arranged in parallel.

Examples of the present invention will be described below.

FIG. 3 shows the configuration of an embodiment of the present invention. One convex lens 3 and three mirrors 4, 5, and 6 are provided between the light source 1 and one image sensor 2. The three mirrors overlap in a direction perpendicular to the plane of the paper, and the first mirror 4 reflects the light beam in the range of θ ₁ so that it enters the entire light receiving range of the image sensor 2, and the second mirror 5 reflects the light beam in the range of θ ₂ so that it enters the entire light receiving range of the image sensor 2, and the third mirror 6 reflects the light beam in the range of θ 2
The light beam in the range of ₃ is reflected so as to be incident on the entire light receiving range of the image sensor 2. The level discrimination circuit 7 inputs the output pulse signal of the image sensor 2 and outputs a level output O ₁ , which indicates the degree of superimposition of the incident light.
Output O ₂ , O ₃ and fractional pulse count output O _N.

Figure 4 shows the optical beam width at each degree of superimposition, the output waveform c of the image sensor, and the level output O ₁ , O ₂ , O ₃
and the waveform of the fractional pulse count output O _N are shown. When the incident light is reflected only by the first mirror 4, the level output in () is O ₁ = 1, O ₂ = O ₃ = 0, and the incident light is reflected by the first mirror 4 and the second mirror 5. When the light is superimposed () the level output is O ₂
= 1, O ₁ = O ₃ = 0, and the incident light is the first and second
And when the reflected light from each of the third mirrors 4, 5, and 6 is superimposed, the level output of () is O ₃ = 1,
O ₁ =O ₂ =0.

FIG. 5 shows optical means of another embodiment of the invention. From the front toward the page, a prism 8 with a triangular cross section, a space without any prisms,
Three optical paths are formed by the prism 9 with an inverted triangular cross section, and the light beam in the range θ ₁ is refracted by the prism 8 and then enters the image sensor 2 via the convex lens 3, and the light beam in the range θ ₂ is refracted by the prism 8. directly enters the convex lens 3 without passing through any prism, and then enters the image sensor 2, and the range θ
₃ is refracted by the prism 9 and then enters the image sensor 2 via the convex lens 3.

FIG. 6 shows optical means of still another embodiment of the invention. Two half mirrors 11 and 12 are disposed between the light beam and the convex lens 3. Of the light reflected by the first half mirror 11, the light mainly in the range θ ₁ is reflected again by the mirror 13 and then enters the image sensor 2 via the convex lens 3. The light in the range θ ₃ is reflected again by the mirror 14 and then enters the image sensor 2 via the convex lens 3, and the light in the range θ ₂ passes through both the first and second half mirrors 11 and 12 and passes through the convex lens. incident on the image sensor 2.

FIG. 7 shows the configuration of an electron refractometer as an application example of the present invention. The principle of this refractometer is to determine the refractive index from the critical angle of total internal reflection. When the sample 22 is placed on the reference prism 21 and light is irradiated from the light source 23, the light emitted from the prism crosses the critical angle. The light and dark are divided into two, and the angle of the boundary between the light and dark changes depending on the refractive index. In the figure, 3
Heavy mirrors 24, 25, 26, convex projection lens 3
The arrangement of the image sensors 2 is the same as the embodiment described in FIG. 3, and a wide range of light beams can be reduced and irradiated onto one image sensor 2.

Of course, the present invention is not limited to the case where one image sensor is used, but also includes the case where a plurality of image sensors are used and the light beams are further superimposed.

According to the present invention, it is possible to utilize a plurality of expensive image sensors, resulting in great economic effects. In addition, the labor for accurately arranging and adjusting a plurality of image sensors in parallel is saved, and manufacturing is easy.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a conventional example, and FIG. 2 is an explanatory diagram of the operation of FIG. 1. FIG. 3 is a block diagram of an embodiment of the present invention, FIG. 4 is an explanatory diagram of the operation of FIG. 3, and FIGS. 5, 6, and 7 are block diagrams showing other embodiments of the present invention. 2... Image sensor, 3... Convex lens, 4,
5, 6...Mirror, 7...Level discrimination circuit, 8,
9...prism, 11,12...half mirror,
13, 14, 24, 25, 26...mirror.

Claims (1)

[Claims] 1. Optical means that reflects and refracts a light beam emitted from a single light source along different optical paths corresponding to multiple divided ranges, and a common image sensor that receives the light beams of the different optical paths in a superimposed manner. and a level determination device that determines the degree of superimposition of received light from the pulse height of the output pulse signal of the image sensor and counts the number of fractional pulse signals.