Small high-brightness strip-shaped light source

Abstract

The utility model relates to a small high-brightness strip-shaped light source which comprises a white laser light source module, a light beam collimation module, a light beam expansion module, a heat dissipation module and a circuit module. The white laser light source module comprises a laser diode module, an optical lens 1, a diffusion sheet and a wavelength conversion sheet which are arranged in sequence; the laser diode module located on the heat dissipation module is driven by the circuit module to generate blue laser, the blue laser is focused through the optical lens 1, then is dodging through the diffusion sheet and then enters the wavelength conversion sheet to convert the blue laser into white laser, the white laser is collimated through the light beam collimation module, and finally emergent light spots are expanded into strip-shaped light spots through the light beam expansion module. The light source is applied to the field of machine vision light sources, and has the advantages of small light source size, high brightness and large light spot length-width ratio.

Description

Technical Field

[0001] The utility model relates to the field of machine vision light sources, and particularly to a small-sized high-brightness bar light source. Background Technique

[0002] Bar light sources are widely used in machine vision to provide the required illumination. Currently, bar light sources are mainly composed of high-density LED arrays, and their huge volume often brings many inconveniences to practical applications. Especially when the workpiece to be irradiated is ultra-slender, the problem is particularly prominent. The narrow width of such workpieces does not match the wide-width output of the light source, resulting in light spilling out of the workpiece edge, and the edge light seriously interfering with the precise detection of the workpiece surface. In addition, in the precision detection pursuing coaxial illumination, the huge volume of traditional bar light sources forces the size of the semi-transparent and semi-reflective mirror to increase sharply, bringing great challenges and inconveniences to manufacturing.

[0003] In view of this, there is an urgent need in the industry for a light source that integrates small volume, high brightness, and large aspect ratio light spots. The introduction of white laser technology provides a new idea for this problem. This technology relies on a laser diode to excite a fluorescent material, and cleverly converts monochromatic laser into white light output. Its unique advantages are small optical expansion and high energy density. Small optical expansion ensures good collimation of the light in the width direction of the light source; high energy density enables the light source to output higher luminous flux compared with mainstream LED light sources, and at the same energy level, its luminous point area is more compact, thus abandoning the traditional array mode of splicing multiple LEDs, greatly promoting the optimization and compactification of the optical system design, and opening up new possibilities for the precise detection of slender workpieces. Summary of the Utility Model

[0004] To solve the above problems, the core of the utility model is to adopt a method of combining a white laser light source with a cylindrical lens, a wavy lens, a Powell lens, and a free-form surface lens to generate a high-brightness light spot with a large aspect ratio, and at the same time make the volume of the light source as small as possible to be suitable for the lighting method of coaxial illumination.

[0005] The utility model is realized through the following technical solutions:

[0006] A small-sized high-brightness bar light source includes a white laser light source module, a beam collimation module, a beam expansion module, a heat dissipation module, and a circuit module; the white laser light source module includes a laser diode module, an optical lens 1, a diffuser, and a wavelength conversion sheet arranged in sequence; the laser diode module located on the heat dissipation module is driven by the circuit module to generate blue laser, which is focused by the optical lens 1, then homogenized by the diffuser and irradiated on the wavelength conversion sheet to convert the blue laser into white laser, and the white laser is collimated by the beam collimation module and finally the outgoing light spot is expanded into a bar light spot by the beam expansion module.

[0007] Further, the laser diode module is composed of one or two or more identical laser diodes, and its emission wavelength is between 430 nm and 470 nm, which is determined according to the required illuminance of the irradiation surface and the size of the width of the irradiation surface.

[0008] Further, the optical lens 1 has a diameter between 4 mm and 60 mm and a focal length between 2 mm and 100 mm. It is a biconvex lens, and both the front and rear surfaces are aspherical. Its function is to collect the blue laser emitted by the laser diode module and focus it.

[0009] Further, the diffusion angle of the diffusion sheet is between 0.5° and 10°, and the thickness is between 0.3 mm and 2.0 mm. The laser is homogenized by the diffusion sheet to improve the tolerance of the wavelength conversion sheet. The angle and thickness of the diffusion sheet need to be determined according to the allowable light-emitting surface size of the white laser light source module. The larger the diffusion angle, the larger the light spot, and the greater the light energy allowed on the wavelength conversion sheet.

[0010] Further, the wavelength conversion sheet converts the laser with a wavelength between 430 nm and 470 nm into white light with a wavelength between 500 nm and 700 nm. The principle is that the blue laser excites the fluorescent layer on the wavelength conversion sheet to generate yellow light, and the yellow light combines with the unabsorbed blue light to turn into white laser. The color temperature of the light source is controlled by controlling the thickness of the fluorescent layer.

[0011] Further, the beam collimation module includes an optical lens 2 and an optical lens 3. Its main function is to collimate the white laser on the wavelength conversion sheet, so as to enable the subsequent shaping module.

[0012] Further, the beam collimation module has an adjustment structure, which can slightly adjust the distance between the optical lens 3 and the optical lens 2, and finely adjust the spot width at the specified working distance.

[0013] Further, the optical lens 2 has a diameter between 6 mm and 20 mm and a focal length between 4 mm and 15 mm. It is a biconvex lens, and its function is to collect the white laser of the wavelength conversion sheet and initially reduce the divergence angle of the light source.

[0014] Further, the optical lens 3 has a diameter between 10 mm and 40 mm and a focal length of 15 mm to 150 mm. It is a plano-convex lens, and its function is to collimate the white laser together with the optical lens 2. The better the collimation, the smaller the spot width of the light source at the specified working distance.

[0015] Further, the optical lens 3 can be a doublet lens. An aperture stop is added between the optical lens 2 and the doublet lens to form the principle of Köhler illumination to homogenize the light source. The doublet lens can also eliminate the chromatic dispersion caused by white light, making the critical part of the light spot clearer and without color spots. The doublet lens and the aperture stop are used in combination in occasions with high lighting requirements.

[0016] Further, the beam expander module can be one or a combination of a wavy lens, a cylindrical lens, a Powell lens, and a free-form lens.

[0017] Further, the beam expander module can be a wavy lens with an aperture diameter between 4 mm and 40 mm and a designed angle of 90 - 140°. Its function is to expand the collimated beam into a long strip in the length direction and remain basically unchanged in the width direction. When the aperture diameter of the optical lens 3 is larger than that of the wavy lens, an aperture stop needs to be added between the aspherical lens 3 and the wavy lens to block stray light and prevent a circular spot from appearing in the middle of the expanded long-strip light spot.

[0018] Further, the size of the heat dissipation module changes according to the number of laser diodes. The more the number of laser diodes, the larger the size of the radiator. A cooling fan can also be added to dissipate heat to ensure the stable operation of the laser diode module.

[0019] Further, the circuit module controls the lighting and extinguishing of the laser diode and also includes adjustment buttons to adjust the energy of the light source to meet different energy lighting requirements.

[0020] The utility model has the following beneficial effects:

[0021] (1) Small volume: Only a single light source is used, and the volume is much smaller than that of an array-type LED. Also, a large semi-transmissive and semi-reflective mirror is not required for coaxial illumination. (2) Large aspect ratio of the light spot: A white laser light source is used, with a small optical extension, good collimation, a relatively narrow width, and a large expansion angle, so that the light spot can be made longer. (3) High brightness: A white laser light source is used, with a high energy density, and the illuminance is higher under the same illumination area. Description of the Drawings

[0022] Figure 1 It is a block diagram of a small-sized high-brightness bar light source system.

[0023] Figure 2 It is a schematic structural diagram of a small-sized high-brightness bar light source with a single laser diode using a wavy lens, where 1, laser diode module; 2, optical lens 1; 3, diffuser; 4, wavelength conversion sheet; 5, optical lens 2; 6, optical lens 3; 7, wavy lens; 8, metal housing.

[0024] Figure 3The theoretical spot diagram simulated by LightTools for Example 1.

[0025] Figure 4 Schematic diagram of the structure of a small high-brightness bar light source with 8 laser diodes using a doublet lens, where 1 is the laser diode module; 2 is the optical lens 1; 3 is the diffuser; 4 is the wavelength conversion wheel; 5 is the optical lens 2; 6 is the doublet lens; 7 is the wavy lens; 8 is the metal housing; 9 is the aperture.

[0026] Figure 5 The theoretical spot diagram simulated by LightTools for Example 2.

[0027] Figure 6 Schematic diagram of the structure of a small high-brightness bar light source with a single laser diode using a cylindrical lens, where 1 is the laser diode module; 2 is the optical lens 1; 3 is the diffuser; 4 is the wavelength conversion sheet; 5 is the optical lens 2; 7 is the cylindrical lens; 8 is the metal housing..

[0028] Figure 7 The theoretical spot diagram simulated by LightTools for Example 3.

[0029] Figure 8 Schematic diagram of the structure of a small high-brightness bar light source with a single laser diode using a free-form lens, where 1 is the laser diode module; 2 is the optical lens 1; 3 is the diffuser; 4 is the wavelength conversion sheet; 7 is the free-form lens; 8 is the metal housing.

[0030] Figure 9 Schematic diagram of the free-form lens model in Example 4.

[0031] Figure 10 The theoretical spot diagram simulated by LightTools for Example 4. Detailed implementation manners

[0032] To more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments and the accompanying drawings. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0033] Refer to Figure 1 For the block diagram of the small high-brightness bar light source system, with a white laser light source as the core, the light source is collimated as much as possible through the beam collimation module, and then expanded into a bar-shaped spot through the beam expansion module. The heat dissipation module ensures the stable operation of the white laser light source. While the circuit module powers the light source, it can adjust the output of the light source to meet the lighting requirements of different occasions.

[0034] Example 1: Refer to Figure 2Schematic diagram of a small-sized high-brightness strip light source structure using a single laser diode with a wavy lens. A single laser diode is used, with an emission wavelength of 450 nm and a light power of 5 W. The aperture of the optical lens 1 is 6.33 mm and the focal length is 4.05 mm. The light is focused onto a diffuser sheet. The diffusion angle of the diffuser sheet is 5°, and its thickness is 0.7 mm. The color temperature of the wavelength conversion sheet is 6500 K. The shape of the light-emitting surface on the wavelength conversion sheet is close to circular, with a diameter of approximately 0.5 mm. The aperture of the optical lens 2 is 6.5 mm and the focal length is 4.2 mm. The white laser light on the wavelength conversion sheet is collected as much as possible and then passes through the optical lens 3 with an aperture of 15 mm and a focal length of 10.5 mm to collimate the white laser light, with a beam width of 10 mm. A wavy lens with a diameter of 14 mm and a clear aperture of 10 mm and a designed angle of 90° is used. Refer to Figure 3 At 120 cm, the spot width is 6.2 cm, the length is 220 cm, and the average illuminance is 9751 lux.

[0035] Example Two: Refer to Figure 4 Schematic diagram of a small-sized high-brightness strip light source structure using eight laser diodes with a doublet lens. The number of laser diodes is eight, and the light power is 44 W. The aperture of the optical lens 1 is 16 mm and the focal length is 28 mm. The blue light emitted by the laser diodes is focused onto a diffuser sheet. The diffusion angle of the diffuser sheet is 1.5° and the thickness is 0.7 mm. The diffuser sheet homogenizes the incident laser light and reaches the wavelength conversion sheet. Here, the wavelength conversion sheet is driven by a motor to rotate, improving the bearing capacity of the wavelength conversion sheet. Its light-emitting surface is close to circular, with a diameter of 0.4 mm. The aperture of the optical lens 2 is 10 mm and the focal length is 8 mm. The doublet lens has an aperture of 40 mm and a focal length of 110 mm. A diaphragm with a diameter of 6 mm is added between the optical lens 2 and the doublet lens to form a Köhler illumination structure to homogenize the spot. The doublet lens can also reduce the chromatic aberration caused by white light and improve the light source performance. The wavy lens is a circular shape with a diameter of 38 mm and a designed angle of 120°, closely attached to the light outlet of the doublet lens. Refer to Figure 5 At 100 cm, the spot width is 5 cm, the spot length is 197 cm, and the average illuminance is 25789 lux.

[0036] Example Three: Refer to Figure 6 Schematic diagram of a small-sized high-brightness strip light source structure using a cylindrical lens. The light source part is the same as that in Example One. The aperture of the optical lens 2 is 6 mm and the focal length is 6 mm. The cylindrical lens has an aperture of 20 mm, a focal length of 20 mm, and a length of 20 mm. The light in the width direction is collimated, and the light in the length direction still diverges at the original angle. Refer to Figure 7 At 80 cm, the spot width is 5.0 cm, the spot length is 120 cm, and the illuminance is 7458 lux.

[0037] Example Four: Refer to Figure 8, which is a schematic diagram of a small high-brightness strip light source using a free-form surface lens. The white laser light source part is the same as that in the second embodiment. The light emerging from the wavelength conversion sheet directly passes through the free-form surface lens for shaping. Refer to Figure 9 is a schematic diagram of the free-form surface lens model. The material is PMMA. It is collimated in the width direction and still propagates at the original divergence angle of the white laser in the length direction. Refer to Figure 10 At 80 cm, the spot diameter is 5.0 cm, the spot length is 270 cm, and the illuminance is 15782.4 lux.

[0038] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the drawings are only examples and do not limit the present invention. The object of the present invention has been fully and effectively achieved. The function and structural principle of the present invention have been shown and explained in the embodiments. Without departing from the said principle, any deformation or modification of the embodiments of the present invention is possible.

Claims

1. A small high-brightness strip light source, comprising a white laser light source module, a beam collimation module, a beam expansion module, a heat dissipation module, and a circuit module; the white laser light source module comprises a laser diode module, an optical lens 1, a diffuser, and a wavelength conversion plate arranged in sequence; the laser diode module located on the heat dissipation module is driven by the circuit module to generate a blue laser, which is focused by the optical lens 1, and then uniformed by the diffuser and incident on the wavelength conversion plate to convert the blue laser into a white laser, the white laser is collimated by the beam collimation module, and finally the emitted light spot is expanded into a strip light spot by the beam expansion module.

2. A small high brightness bar light source according to claim 1, characterized in that: The laser diode module is composed of one or two or more identical laser diodes, and the laser wavelength generated by the module is between 430nm and 470nm.

3. A small high brightness bar light source according to claim 1, characterized in that: The optical lens 1 is a biconvex lens with an aperture of 4-60 mm and a focal length of 2-100 mm.

4. A small high brightness bar light source according to claim 1, characterized in that: The diffusion angle of the diffusion sheet is between 0.5° and 10°, and the thickness is between 0.3mm and 2.0mm.

5. The small high-brightness bar light source according to claim 1, characterized in that: The wavelength conversion sheet converts monochromatic laser light with a wavelength between 430nm and 470nm into white light with a wavelength between 500nm and 700nm.

6. The small high-brightness bar light source according to claim 1, characterized in that: The beam collimation module includes an optical lens 2 and an optical lens 3 .

7. A small high brightness bar light source according to claim 6, characterized in that: The aperture of the optical lens 2 is between 6 and 20 mm, and the focal length is between 4 and 15 mm.

8. The small high-brightness bar light source according to claim 6, characterized in that: The aperture of the optical lens 3 is between 10-40 mm, and the focal length is between 15-150 mm.

9. The small high-brightness bar light source according to claim 1, characterized in that: The light beam expansion module is a combination of one or more of a wave lens, a cylindrical mirror, a Powell lens, and a free-form surface lens.

Images