CN104916198A - Self-focusing lens light-concentrating principle simulation demonstration device and experimental method - Google Patents

Abstract

The invention provides a self-focusing lens light-concentrating principle simulation demonstration device. A base is equipped with a transparent water tank with water inside. The right outer side face of the transparent water tank is provided with a white paint layer. The back base outside the transparent water tank is provided with a semiconductor refrigeration chip bracket which is provided with a semiconductor refrigeration chip immersed in the water. The distance between the lower surface of the semiconductor refrigeration chip and the bottom of the water tank is at least 70mm. The front side face of the semiconductor refrigeration chip is a hot face and is perpendicular to a horizontal plane. The laser bracket of a semiconductor laser is installed at the left side on the base outside the transparent water tank. The divergent laser beam with the divergent angle of 15 degrees to 20 degrees emitted by the semiconductor laser goes through the bottom center of the semiconductor laser to be projected to the white paint layer to form a round light spot. The structure of the simulation demonstration device is simple, the speed of establishing a refractive index symmetry decreasing gradient change light-concentrating area is fast, a gradient temperature field direction is stable, a demonstration effect is obvious and intuitive, and the device can be used as an optical demonstrations and experimental instrument.

Description

Self-focusing lens light concentrating principle simulation demonstration device and experimental method

technical field

The invention belongs to the technical field of experimental teaching demonstration instruments, and in particular relates to a self-focusing lens light-gathering principle simulation demonstration device.

Background technique

The concentration of light energy is one of the basic problems in the field of optics and its related technical applications. Concentrating methods are divided into reflective concentrating method and trans-refractive concentrating method. The basic method of reflection and concentrating light is to use concave mirrors to condense light. Concave mirrors are divided into spherical concave mirrors and parabolic concave mirrors, which are widely used. The main element used in the catadioptric concentrating method is the concentrating lens. Concentrating lenses are basic components in scientific research, applied optics, laser processing, optical communication, solar energy utilization and other fields. The Fresnel lens invented by French physicist Fresnel in 1822 has been widely used due to its unique structure and characteristics, and has long been a basic optical element. As we all know, the Fresnel lens is only a deformation of the traditional convex lens geometry in structure, and it still belongs to the transmission-refraction method. It is not difficult for students to understand its principle.

The self-focusing rod lens invented in the 1960s, due to its unique optical characteristics and the characteristics of perfect combination with semiconductor lasers 1 and optical fibers, has been used in optical information such as optical fiber communication, optical fiber sensing, optical instruments, and medical instruments. It has been widely used in transmission and detection. The light-gathering principle of the self-focusing lens is based on the curved transmission of light in a material with a gradient change in refractive index. However, the size of the self-focusing lens that can be manufactured at present is still small, and it is difficult to intuitively see the light in the self-focusing lens. Tracks increase the difficulty for students to understand. Therefore, it is of great significance to develop an experimental demonstration device for the light concentrating principle of the self-focusing lens.

Contents of the invention

A technical problem to be solved by the present invention is to provide a self-focusing lens light-gathering principle simulation demonstration device with reasonable design, simple structure and intuitive demonstration effect.

Another technical problem to be solved by the present invention is to provide an experimental method for simulating a demonstration device using the principle of self-focusing lens light collection.

The technical solution adopted to solve the above technical problems is: a transparent water tank with water inside is installed on the base, a white paint layer is sprayed on the right outer surface of the transparent water tank in the length direction, and a semiconductor refrigeration chip is arranged on the rear base outside the transparent water tank. Bracket, semiconductor cooling chip bracket is provided with a semiconductor cooling chip immersed in water, the distance from the lower surface of the semiconductor cooling chip to the bottom of the water tank is at least 70mm, the front side of the semiconductor cooling chip is a hot surface or a cold surface, and is perpendicular to the horizontal plane, on the base A laser bracket with a semiconductor laser is installed on the left side outside the upper transparent water tank. The divergent laser beam emitted by the semiconductor laser with a divergence angle of 15° to 20° passes directly under the semiconductor refrigeration sheet and is projected on the white paint layer to form a circular spot. .

The geometric shape of the transparent water tank and the semiconductor refrigeration sheet of the present invention is a cuboid, and the hot surface of the semiconductor refrigeration sheet is parallel to the long side wall of the transparent water tank.

The central line of the divergent light beam with a divergence angle of 15° to 20° of the emitted light of the semiconductor laser of the present invention is in the same plane as the central plane of the thickness of the semiconductor refrigerating sheet.

The best divergence angle of the emitted light of the semiconductor laser of the present invention is 18°, and the center line of the divergent light beam is in the same plane as the center plane of the thickness of the semiconductor refrigerating sheet.

The experimental method of using the above-mentioned self-focusing lens concentrating principle to simulate the demonstration device consists of the following steps:

1) Adjust the outgoing light direction and divergence angle of the semiconductor laser to 15°~20°, so that the laser beam emitted by the semiconductor laser passes directly under the semiconductor refrigeration sheet and projects on the white paint layer. Observe the circle on the white paint layer at this time. The uniformity of the brightness of the shaped spot;

2) Turn on the power supply of the semiconductor refrigeration chip, and observe the vertical bright light band formed in the circular light spot on the white paint layer and the brightness change on both sides of the vertical bright light band.

In the present invention, the energized semiconductor refrigerating sheet is suspended vertically in the water, and the thin layer of cold flow generated by the continuous heat absorption of the cold surface of the semiconductor refrigerating sheet migrates to the bottom of the water tank. The gradient temperature field formed by the exchange, the law of symmetrical and decreasing change of the refractive index of water formed on both sides of the cold flow thin layer is similar to the law of radial change of the self-focusing lens refractive index, and the necessary refractive index for demonstrating the principle of self-focusing lens light collection is established. Spotlight area with symmetrical decreasing gradient change. At the same time, when the divergent laser beam passes through the water refractive index symmetrical decreasing change area formed on both sides of the cold flow thin layer along the length direction of the semiconductor refrigeration sheet, the light rays on both sides of the cold flow are deflected to the cold flow thin layer to form the concentrating effect. , to realize the simulation and visual demonstration of the principle of self-focusing lens light collection. The self-focusing lens focusing principle simulation demonstration device with this structure has a simple structure, fast speed of establishing a symmetric refractive index gradient change focusing area in water, stable gradient temperature field direction, obvious and intuitive demonstration effect, and can be used as an optical demonstration and laboratory apparatus.

Description of drawings

Fig. 1 is a schematic structural diagram of Embodiment 1 of the present invention.

Fig. 2 is a photograph of a circular light spot when the peltier 4 is not powered.

FIG. 3 is a photo of a vertical bright light band formed on the circular light spot after the semiconductor cooling chip 4 is energized.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

Example 1

In Fig. 1, the self-focusing lens concentrating principle simulation demonstration device of the present embodiment is connected by a semiconductor laser 1, a transparent water tank 2, a semiconductor cooling chip support 3, a semiconductor cooling chip 4, a white paint layer 5, a laser bracket 6, and a base 7 constitute.

A transparent water tank 2 is placed on the base 7, and the transparent water tank 2 is made of plexiglass, and can also be made of quartz glass. The geometric shape of the transparent water tank 2 is a cuboid, and the transparent water tank 2 is filled with water. A white paint layer 5 is sprayed on the side, and the white paint layer 5 is used to display the shape of the projected spot. On the rear base 7 outside the transparent water tank 2, a semiconductor refrigeration sheet support 3 is placed, and a semiconductor refrigeration sheet 4 is suspended on the semiconductor refrigeration sheet support 3. The semiconductor refrigeration sheet 4 is immersed in water, and the geometric shape of the semiconductor refrigeration sheet 4 is a cuboid. The front side of refrigerating sheet 4 is a thermal surface, by switching the power supply connection polarity of semiconductor refrigerating sheet 4, also can make the front side of refrigerating sheet 4 be cold surface, the hot surface of refrigerating sheet 4 is perpendicular to horizontal plane, the hot surface and The front side wall of the transparent water tank 2 is parallel, and the upper surface is parallel to the horizontal plane. The distance from the lower surface of the semiconductor refrigeration sheet 4 to the bottom of the transparent water tank 2 is 70mm, and the specific distance from the lower surface of the semiconductor refrigeration sheet 4 to the bottom of the water tank should be specific according to the height of the glass water tank. Sure.

On the left side of the transparent water tank 2 on the base 7, a laser support 6 is placed, and a semiconductor laser 1 is installed on the laser support 6. The semiconductor laser 1 can rotate on the support of the semiconductor laser 1, and the semiconductor laser 1 is used to generate laser light. The outgoing light direction and the divergence angle are adjustable, and the divergence angle of the outgoing light of the semiconductor laser 1 in this embodiment is 18°. The center line of the divergent light beam is in the same plane as the central plane of the thickness of the semiconductor refrigeration sheet 4, and the semiconductor laser 1 emits a divergent laser beam. Passing directly below the semiconductor refrigeration chip 4, the circular light spot is formed by projecting on the white paint layer 5.

The experimental method steps of using the self-focusing lens concentrating principle of the present embodiment to simulate the demonstration device are as follows:

1. Adjust the outgoing light direction and divergence angle of the semiconductor laser 1 to be 18°, so that the laser beam emitted by the semiconductor laser 1 passes directly below the semiconductor cooling plate 4 and projects on the white paint layer 5. Observe this on the white paint layer 5 When the uniformity of the circular spot, as shown in Figure 2. It can be seen from Figure 2 that when the water temperature in the transparent tank is uniform, the circular light spots formed are uniform.

2. Turn on the power supply of the semiconductor refrigerating sheet 4, and observe the vertical bright light band formed in the circular light spot on the white paint layer 5 and the brightness change on both sides of the vertical bright light band, as shown in FIG. 3 . It can be seen from Figure 3 that a vertical bright light band is formed on the circular light spot, and the brightness on both sides of the vertical bright light band drops significantly, indicating that the light on both sides of the vertical bright light band gathers toward the vertical bright light band, and the mechanism of this phenomenon and self-focusing are analyzed The similarity of lens concentrating principle.

Example 2

On the rear base 7 outside the transparent water tank 2, a semiconductor refrigeration sheet support 3 is placed, and a semiconductor refrigeration sheet 4 is suspended on the semiconductor refrigeration sheet support 3, and the semiconductor refrigeration sheet support 3 and the semiconductor refrigeration sheet 4 are immersed in water, and the semiconductor refrigeration sheet 4 The geometric shape is a cuboid, the front side of the semiconductor refrigeration sheet 4 is a hot surface, the hot surface of the semiconductor refrigeration sheet 4 is perpendicular to the horizontal plane, the hot surface is parallel to the front side wall of the transparent water tank 2, and the upper surface is parallel to the horizontal plane, and the semiconductor refrigeration sheet 4 is lowered. The distance from the surface to the bottom of the transparent tank 2 is 70mm. Other components and the coupling relationship of the components are the same as in Embodiment 1. A laser bracket 6 is placed on the left side of the transparent water tank 2 on the base 7, and a semiconductor laser 1 is installed on the laser bracket 6. The divergence angle of the semiconductor laser 1 outgoing light in this embodiment is 15°, and the center line of the divergent light beam is in line with the semiconductor cooling plate 4. The central plane of the thickness is in the same plane, and the divergent laser beam emitted by the semiconductor laser 1 passes directly under the semiconductor cooling chip 4 and is projected on the white paint layer 5 to form a circular spot. Other components and the coupling relationship of the components are the same as in Embodiment 1.

The experimental method steps of using the self-focusing lens concentrating principle of the present embodiment to simulate the demonstration device are as follows:

In step 1, adjust the outgoing light direction and divergence angle of the semiconductor laser 1 to be 15°, the laser beam that makes the semiconductor laser 1 exit passes directly below the semiconductor refrigeration sheet 4, and is projected on the white paint layer 5, on the white paint layer 5 Observe the uniformity of the brightness of the circular spot at this time. Step 2 is the same as Example 1.

Example 3

On the rear base 7 outside the transparent water tank 2, a semiconductor refrigeration sheet support 3 is placed, and a semiconductor refrigeration sheet 4 is suspended on the semiconductor refrigeration sheet support 3, and the semiconductor refrigeration sheet support 3 and the semiconductor refrigeration sheet 4 are immersed in water, and the semiconductor refrigeration sheet 4 The geometric shape is a cuboid, the front side of the semiconductor refrigeration sheet 4 is a hot surface, the hot surface of the semiconductor refrigeration sheet 4 is perpendicular to the horizontal plane, the hot surface is parallel to the front side wall of the transparent water tank 2, and the upper surface is parallel to the horizontal plane, and the semiconductor refrigeration sheet 4 is lowered. The distance from the surface to the bottom of the transparent tank 2 is 80mm. Other components and the coupling relationship of the components are the same as in Embodiment 1. A laser bracket 6 is placed on the left side of the transparent water tank 2 on the base 7, and a semiconductor laser 1 is installed on the laser bracket 6. The divergence angle of the semiconductor laser 1 outgoing light in this embodiment is 20°, and the centerline of the divergent light beam is in line with the semiconductor cooling plate 4. The central plane of the thickness is in the same plane, and the divergent laser beam emitted by the semiconductor laser 1 passes directly under the semiconductor cooling chip 4 and is projected on the white paint layer 5 to form a circular spot. Other components and the coupling relationship of the components are the same as in Embodiment 1.

The experimental method steps of using the self-focusing lens concentrating principle of the present embodiment to simulate the demonstration device are as follows:

In step 1, adjust the outgoing light direction and divergence angle of the semiconductor laser 1 to be 20 °, the laser beam that makes the semiconductor laser 1 exit passes directly below the semiconductor refrigeration sheet 4, and is projected on the white paint layer 5, on the white paint layer 5 Observe the uniformity of the brightness of the circular spot at this time. Step 2 is the same as Example 1.

The working principle of the present invention is as follows:

After the semiconductor refrigerating sheet 4 immersed in water is energized, the cold surface of the semiconductor refrigerating sheet 4 absorbs heat continuously, and the water in contact with the cold surface is absorbed and cooled. Surface is in the water of normal temperature state and replenishes to the cold surface of semiconductor refrigeration sheet 4 again, has cold water to flow to the water below semiconductor refrigeration sheet 4 constantly on the cold surface of formation semiconductor refrigeration sheet 4 with this. The cold water flowing downward along the cold surface of the semiconductor refrigeration sheet 4 forms a thin layer of cold flow in the water. At the same time, the thin layer of cold flow exchanges heat with the water on both sides, forming a symmetrical direction and cold flow on both sides of the thin layer of cold flow. A positive gradient temperature field perpendicular to the thin layer. The density of water above 4°C is inversely proportional to the temperature, and the greater the density of water, the greater the refractive index, that is, the lower the water temperature, the higher the refractive index, forming a symmetrical refractive index from large to small on both sides of the cold flow thin layer Gradient change area. Since the light is always deflected to the region with a large refractive index during the transmission process, the laser beam passing through the cold flow thin layer longitudinally produces deflection in different directions in the positive gradient temperature field that is symmetrical and opposite in direction on both sides of the cold flow thin layer. The divergent laser beam is gathered in the middle, and the mechanism of this light-concentrating phenomenon is exactly the same as that of the self-focusing lens, so as to realize the intuitive demonstration of the light-condensing principle of the self-focusing lens.

Claims (5)

1. A self-focusing lens concentrating principle simulation demonstration device, characterized in that: a transparent water tank (2) with water inside is set on the base (7), and a white paint layer is sprayed on the right outer surface of the transparent water tank (2) (5), the rear base (7) outside the transparent water tank (2) is provided with a semiconductor refrigeration sheet support (3), and the semiconductor refrigeration sheet support (3) is provided with a semiconductor refrigeration sheet (4) immersed in water. The distance from the lower surface of the chip (4) to the bottom of the water tank is at least 70mm, the front side of the semiconductor cooling chip (4) is a hot or cold side, and is perpendicular to the horizontal plane, and the left side outside the transparent water tank (2) on the base (7) A laser bracket (6) with a semiconductor laser (1) is installed on the side, and the divergent laser beam emitted by the semiconductor laser (1) with a divergence angle of 15° to 20° passes directly under the semiconductor cooling plate (4) and is placed on the white paint layer. (5) The upward projection forms a circular spot. 2. The self-focusing lens concentrating principle simulation demonstration device according to claim 1, characterized in that: the geometric shape of the transparent water tank (2) and the semiconductor cooling chip (4) is a cuboid, and the semiconductor cooling chip (4) The hot surface of the transparent tank (2) is parallel to the length of the side wall. 3. The self-focusing lens concentrating principle simulation demonstration device according to claim 1, characterized in that: the center line of the divergent beam with the divergence angle of the emitted light of the semiconductor laser (1) being 15°-20° and the semiconductor refrigeration The center planes of the thickness of the sheet (4) are in the same plane. 4. The self-focusing lens concentrating principle simulation demonstration device according to claim 1, characterized in that: the center line of the divergent beam with the divergence angle of the emitted light of the semiconductor laser (1) is 18° and the semiconductor cooling chip (4 ) thickness of the central plane in the same plane. 5. an experimental method using the self-focusing lens concentrating principle simulation demonstration device according to claim 1, is characterized in that being made up of following steps: 1) Adjust the outgoing light direction and divergence angle of the semiconductor laser (1) to 15° to 20°, so that the laser beam emitted by the semiconductor laser (1) passes directly under the semiconductor cooling sheet (4) and is projected on the white paint layer (5 ), observe the uniformity of the brightness of the circular spot on the white paint layer (5); 2) Turn on the power supply of the semiconductor cooling chip (4), and observe the vertical bright light band formed in the circular light spot on the white paint layer (5) and the brightness changes on both sides of the vertical bright light band.