KR20050000692A - Optical system applying pulse type laser diode - Google Patents

Abstract

PURPOSE: An optical system equipped with a pulse type laser diode is provided to prevent an optical alignment from being easily misaligned and to prevent a size of a system from being enlarged. CONSTITUTION: An optical system equipped with a pulse type laser diode includes a first beam divider(3). The first beam divider(3) reflects light having a predetermined wavelength and allow light having other wavelength to pass through. A transmitting and receiving lens is disposed at a front portion of the first beam divider(3) in order to transmit a laser and to receive light dispersed from an object. A second beam divider(5) allows a visible light to pass through and reflects the laser. A first mirror is provided to reflect a pulse type laser towards the first beam divider(3).

Description

Optical system employing a pulsed laser diode {Optical system applying pulse type laser diode}

The present invention relates to an optical system, and more particularly to an optical system for measuring the distance and the speed of a desired object using a pulsed laser.

Techniques for measuring the distance and speed of a desired object using pulsed lasers are well known and commercially available.

1 is a view showing the configuration of a general optical system for a range finder.

Referring to FIG. 1, the optical system includes a laser 12, beam expanders 13-1 and 13-2 for reducing the divergence angle of the laser light, a lens 14 and a sensor for collecting scattered light and entering the sensor. 16). The light monitoring device includes a lens 15 having a long focal length and a CCD 17. In the far field, when the three lenses are aligned in the same direction, they are aimed at almost the same target, but they are facing different parts at close range.

Even in the case of a general laser, the divergence angle of the laser is several m rad, so the beam size increases at a long distance, thereby reducing the amount of light received by the sensor.

Because of this problem, the laser beam is generally enlarged using a beam magnifier consisting of two lenses and irradiated into the atmosphere. The receiving optical system receives the light scattered back from the object and scattered back in the direction of the laser in the direction of the laser and sends it to the sensor, which requires another large-diameter lens. Therefore, the transmitting optical system including the laser and the receiving optical system are naturally separated and the two axes do not coincide, so that the scattered signal at a short distance makes it difficult for the optical axis to enter the sensor. In addition, it is expensive in terms of commercialization because two large diameter lenses must be used.

In addition, if several objects exist at the same time, only a certain target is to be measured and if the speed distance of the object is to be measured separately, a monitoring system is required.In this case, a CCD camera with a long focal length lens and a long focal length lens can be distinguished. The same new system is needed. In other words, each optical system required for transmission, reception, and monitoring is required. In the case of using an independent optical system, there is a problem in that the alignment of the optical system is easily broken, as well as a cost problem, so that in actual use, the alignment is often inconvenient.

In order to solve this problem, even when using a polarizer as a beam splitter, the pulsed high output diode laser is generally non-polarized and has a disadvantage in that the signal size is reduced because only some polarized light is emitted from the light scattered from the object.

And although there is an example using other specially designed optical system, there is no device to obtain the advantages as the present invention by utilizing the spatial characteristics of the laser for transmission and reception and monitoring.

In the prior art related to the present invention

1) "laser range finder", Tatsumi Kenji, Publication number (58102108A)

2) "Laser measuring device", Japan Electric Corporation, Patent application publication number (特 開平 7-35860)

3) "laser distance measurement instrument", Asakawa yoshohiro, and JP7035860.

It is therefore an object of the present invention to provide a method for solving the above problems of the prior art.

Another object of the present invention is to provide an optical system which can easily prevent the optical alignment from collapsing, to compensate for the disadvantage of increasing the size of the system, and to reduce the manufacturing cost.

1 is a view showing the configuration of a general optical system,

2 is a view showing the configuration of a single optical system according to an embodiment of the present invention,

3 is a diagram illustrating a configuration of the beam splitter shown in FIG. 2.

<Explanation of symbols for the main parts of the drawings>

1 pulsed diode laser 2 prism (or mirror)

3: special coating first beam splitter 4: large-diameter lens

5: special coating second beam splitter 6: alternative lens

7: eye or CCD 8: prism (or mirror)

8 mirror or prism 9 sensor 10 amplifier 11 computer

12: pulsed diode laser 13: beam expander

14: large-diameter lens for reception 15: large-diameter lens for monitoring

16: sensor 17: CCD camera

18: surface transmitting laser light 19: surface reflecting laser light

The present invention for achieving the objects of the present invention as described above

A first beam splitter that reflects light of a wavelength corresponding to a predetermined laser and transmits another wavelength, a transmission / reception lens positioned in front of the first beam splitter, transmitting a laser, and receiving scattered light from an object; And a second beam splitter that transmits visible light of the light received from the lens and reflects the laser. Here, the transceiving lens is a large-diameter lens, and means a lens that is responsible for transmitting and receiving light.

In addition, the embodiment according to the present invention further comprises a first mirror for reflecting the pulsed laser light to the first beam splitter.

Another embodiment according to the present invention further includes an input lens for inputting visible light transmitted by the second beam splitter to a monitoring device, and a second mirror for inputting a laser reflected by the second beam splitter to a sensor. . Herein, the input lens is an alternative lens, and means a lens that is responsible for inputting light to the monitoring device.

In addition, the first beam splitter and the second beam splitter are characterized in that the laser beam reflecting surface 19 is coated on the center and the laser beam transmitting surface 18 is coated on the outside.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the following, the principles of the present invention will first be described, and then embodiments according to the principles of the present invention will be described.

Principle of the Invention

The principle of the present invention is to prevent the effect of collapsing optical alignment easily, to compensate for the disadvantage of oversizing the system, and to reduce the manufacturing cost, a large diameter lens which is a key component of the CCD camera and the transmission / reception optical system as one lens. To cope.

In addition, the present invention, by utilizing the beam characteristics of the elongated semiconductor laser, unlike the shape of a general laser having a spatial shape of a spherical shape, has proposed a specially manufactured first beam splitter (3) unlike the conventional method through which the transmission laser Reflects and vice versa the device which transmits. In addition, a second beam splitter manufactured by the same method (5) was placed near the focal plane of the same lens to separate the light incident to the sensor and the CCD so as to transmit visible light and reflect laser light. The reflected signal is once again reflected from the mirror and input to the sensor.

The visible light transmitted from the second beam splitter 5 is directly incident on the CCD or the position and the coating are performed so that the image is formed on the surface of the CCD sensor by the lens 6.

<Example>

When measuring the distance / speed of a desired object by using a pulsed laser, measure the distance by measuring the time interval between the pulse signal scattered from the desired object and the two pulse signals scattered from the laser transmitter at high speed, and then again After this, the distance is measured to find the difference between the two distances and divided by time to measure the speed. For this purpose, the laser should operate with high repetition rate and the divergence angle should be as small as possible.

2 is a view showing the configuration of a single optical system for measuring distance / speed according to an embodiment of the present invention.

Referring to FIG. 2, the pulsed diode 1 generates a pulsed laser, and the first mirror 2 reflects the pulsed laser to the first beam splitter 3. The first beam splitter 3 reflects light of a wavelength corresponding to a predetermined laser and transmits other wavelengths. The large-diameter lens 4 is located in front of the first beam splitter 3, transmits a laser, and receives light scattered from the object. The second beam splitter 5 transmits visible light of the light received from the large-diameter lens 4 and reflects the laser. The alternative lens 6 inputs the visible light transmitted by the second beam splitter to the CCD camera 7. The second mirror 8 inputs the laser reflected by the second beam splitter to the sensor. The amplifier 10 amplifies the output of the sensor and inputs it to the computer 11.

Specific features of the single optical system having the configuration as described above are as follows.

Transmitted / received lenses (ie, large-diameter lenses) are transmitted through a first mirror (2) for reflecting a pulsed laser and a first beam splitter (3) for reflecting only light of a wavelength corresponding to the laser and transmitting light of other wavelengths. It enters into (4). Although the size of the incident light is increased, the divergence angle is small, so there is no spread of light even in a long distance.

The special beam splitter, that is, the first beam splitter 3 and the second beam splitter 5, is configured as shown in FIG. The structure is coated with a laser beam reflecting surface 19 at the center and a laser beam transmitting surface 18 at the outside. Since the shape of the pulsed diode laser is elongated up / down or left and right, the center portion of the laser wavelength is reflected at 45 degrees and the remaining portion is coated to transmit at all wavelengths.

The light scattered from the object is scattered in all directions, and since the incident light in the lens direction is spherical, most of the light passes through the outer surface 18 of the first beam splitter 3 and a part of the center surface 19 is scattered. Will be incident to and reflected. The transmitted light is reflected by the second beam splitter 5 having the same optically-transmissive reflectivity in the state where the size is reduced again and is incident on the sensor. On the other hand, since the light used for the monitor is the wavelength of the visible light region, the light is transmitted through the beam splitter 5 to form an image on the CCD sensor surface with the lens 6 again.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. For example, in the configuration of the present invention, the monitoring device or the mirror except for the essential components can be replaced by any number of components of the equivalent range. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention has an advantage of complementing the shortcomings of the optical system for distance / speed measurement composed of several lenses.

In addition, since the range finder constructed according to the principles of the present invention is composed of the same lens, the alignment is stable, the size of the system is small, and there is no need to use multiple expensive large diameter lenses. In addition, because the same optical system is configured, the beam alignment is stable, and the product quality can be improved.

Claims (5)

In an optical system employing a pulsed laser diode, A first beam splitter that reflects light of a wavelength corresponding to a predetermined laser and transmits other wavelengths; A transmission / reception lens positioned in front of the first beam splitter and transmitting a laser and receiving scattered light from an object; And a second beam splitter for transmitting visible light of the light received from the lens and reflecting the laser. The method of claim 1, And the first mirror reflecting a pulsed laser to the first beam splitter. The method of claim 1, An input lens for inputting visible light transmitted by the second beam splitter to a monitoring device; The optical system according to claim 2, further comprising a second mirror for inputting a laser reflected by the second beam splitter to a sensor. In an optical system employing a pulsed laser diode, A first mirror 2 reflecting the pulsed laser to the first beam splitter, A first beam splitter (3) which reflects light of a wavelength corresponding to a predetermined laser and transmits other wavelengths; A large-diameter lens 4 positioned in front of the first beam splitter and transmitting a laser and receiving scattered light from an object; A second beam splitter 5 for transmitting visible light of the light received from the lens and reflecting the laser; An alternative lens 6 for inputting visible light transmitted by the second beam splitter to a monitoring device; And a second mirror (8) for inputting a laser reflected by the second beam splitter to a sensor. The method according to any one of claims 1 to 4, The first beam splitter and the second beam splitter The optical system, characterized in that the laser light reflecting surface (19) is coated on the center, the laser light transmitting surface (18) is coated on the outside.